OK TUBROD CORED WIRES PRODUCT BRIEF

Transcription

1 OK TUBROD CORED WIRES PRODUCT BRIEF 1999 EDITION

2 Index Click to page The cored wire process OK Tubrod cored wires Product characteristics OK Tubrod metal cored range OK Tubrod self-shielded range OK Tubrod flux cored range OK Tubrod stainless cored wires Robotic welding and cored wires Shielding gas Modes of weld metal transfer Operating conditions Welding techniques Electrode extension Deposition Data OK Tubrod estimating data Mechanical properties Welding procedure data Welding of stainless steel Welding of clad steel Welding of dissimilar steels Schaeffler diagram One sided welding and non fusible backing AWS classifications for cored wire European Standard EN 758: Cored wire alternatives to manual arc Cored wire fault finding Cored wire selection Welding equipment OK Tubrod submerged arc welding Submerged arc metal cored range Submerged arc flux cored range Operating conditions Welding equipment Welding techniques HV fillet joint data Selected welding procedures Electrogas welding Calculating electrode consumption Stress and energy units conversion Welding data tables Conversions and information

3 The cored wire process Main Features Fundamentally the process is MIG/MAG welding and utilises the same equipment as that for solid wire albeit of larger capacity in some cases. The important difference between MIG/MAG welding with solid wire and cored wire is performance in productivity, welding characteristics and weld metal integrity. Variations to suit a particular application or physical requirement are more easily achieved than with solid wire. This involves changes in the filling formulation and to percentage of fill in a similar way to that of manual arc electrodes. The coating formulation and thickness can have a significant effect, whereas little can be done with the electrode core wire alone to improve aspects of performance. Economics Whilst there are higher productivity processes available, such as submerged arc and robotics, cored wire semiautomatic MIG offers the fabricator a more flexible process with genuine increases in productivity for the least capital expenditure. Where solid wire is already in use this may only involve a change of accessories such as feed rolls and torch consumables. A move to cored wire MIG/MAG from the use of manual arc will obviously involve the purchase of new equipment but the undisputed increase in productivity will usually guarantee a return on capital invested in less than one year. Deposition The higher deposition rate from cored wires relies upon the I 2 R heating effect which is greater than with solid wires, at a given current. SOLID METAL CORED FLUX CORED With the solid wire the total cross section carries all of the current but with metal cored wires a partial amount is carried by the core and in the case of flux cored wire all of the current is conducted by the tube. Therefore the current density and hence heating effect ensures a higher burn-off rate from cored wires. Cored Wire Cross-sections Closed Butt - this type predominates in the Tubrod range lending itself to a wide variety of sizes and fill percentages between 18-33% depending on size required. Overlap - frequently the need arises to fill with the normal slag formers and a high percentage of additional allying elements. Stainless steel and hardsurfacing types are typical examples where this section is employed with fill percentages between 30-50%. The thinner wall section has the advantage of even higher current density and hence deposition rate. OK Tubrod cored wires The ESAB range consists of rutile and fully basic flux cored wires, some of which are self-shielded, and a range of metal cored wires. For general fabrication work the metal cored type could satisfy the majority of applications, so the need for three principal types may be questioned. There are a number of factors to be considered and can be summarised as follows:- Downhand Rutile Flux Cored Wires are easy to use with a smooth arc action giving excellent weld appearance with easy slag detachment. Positional Rutile Flux Cored Wires when used with Argon rich gas offer spray transfer welding with a high level of operator appeal. Basic Flux Cored Wires produce a higher and more consistent level of mechanical properties. They also produce radiographic standard deposits with ease when compared to both rutile and metal cored wires. Metal Cored Wires when used on good quality clean plate will produce very little slag-similar to that of solid wires. Self-Shielded Wires produce their own gas shield via decomposition in the arc of various elements within the core.

4 Product characteristics Rutile The rutile OK Tubrod wires may be subdivided into two types. They can be of the EXOT-1 type for high deposition downhand and HV operation, or the EX1T-1 for all positional welding. EX0T-1 Downhand and HV OK Tubrod and OK Tubrod come within this group for use with CO 2 shielding, whilst the OK Tubrod is designed for Ar + 20% CO 2, or CO 2 shielding gases. Sizes range from 1.2mm up to 2.4mm. Exceptionally smooth high current operating characteristics, giving low spatter and a regular weld appearance. Very high deposition rates. Slag removal is effortless and self releasing on HV fillets. Ideally suited to the mass production of heavy equipment in a wide variety of mild and medium tensile steels. DC electrode positive. Universally approved to Grade 2 by all major certification authorities. EX1T-1 All Positional OK Tubrod and OK Tubrod are included under this heading, together with a number of low alloy OK Tubrod wires which have a similar slag system. The majority may be used with either Ar + 20% CO 2, or CO 2, although the low alloy types benefit from the Ar rich gas in terms of improved operability. Sizes range from 1.2mm to 1.6mm. Low hydrogen quality weld metal. Universally approved to Grade 3. Smooth regular weld appearance with minimum spatter. Excellent slag release qualities. Consistent spray type transfer in any position for higher deposition. Ability to operate at one current setting in any position if required. Ideal for open butt joints in conjunction with ceramic backing. Basic OK Tubrod basic low hydrogen wires are in the EX1T-5 category for all position welding of mild, medium and high tensile steels, together with various low alloy versions. The high purity weld metal also ensures that they possess excellent sub-zero notch toughness. They are designed for either CO 2, or Argon + 20% CO 2 shielding gases. Outstanding deposit efficiency up to 90% at optimum currents, giving higher deposition rates than other flux cored wires. Thin slag cover which is very easily removed hence reducing the incidence of slag traps. Operate with DC electrode negative. The 1.2mm sizes are excellent for all positional welding using dip transfer. Hydrogen levels are lower than 5mls/100gms of weld metal generally less than 3mls/100gms. Recommended for single or multi-pass welding of heavy sections under conditions of restraint. Self Shielded Designed for on-site operation OK Tubrod (E71T-7) is for welding mild steel in all positions and OK Tubrod (E70T-4) for heavy deposition and/or high travel speeds in the flat and HV positions where impact properties are not required. Higher deposition than manual metallic arc electrodes. No requirement for special purpose welding equipment. Good clean weld appearance and easy slag removal. May be used with either flat or drooping characteristic power sources. For use with most structural steels with a nominal tensile strength of 510 N/mm 2. Metal Cored A wide range of OK Tubrod metal cored wires is available to suit a variety of applications from high speed general purpose welding to low temperature and high strength requirements. The metal core produces an exceptionally high recovery, enabling approximately 95% of the wire weight to be deposited as weld metal. Used in conjunction with argon rich gases containing 15/25% CO 2 weld deposits of smooth consistent finish with minimal spatter and slag are easily produced. Fume levels are significantly lower than those of conventional flux cored wires and approximately 50% less than high recovery iron powder manual arc electrodes. Weld metal savings of up to 30% can be achieved on single pass fillets through deep penetration which increases the effective throat thickness with a corresponding reduction in leg length of up to 20%. Further economies can be realised by a reduction in deposited weld metal through the use of smaller preparation angles. All OK Tubrod metal cored wires produce low hydrogen quality weld metal. Metal cored wires have the advantage in catering for the majority of downhand applications at one current setting.the only variable necessary is the travel speed which will determine the size of deposit. Note: All classifications referred to are AWS see page 53 and 54

5 OK Tubrod metal cored range OK Tubrod A metal cored tubular wire for welding mild and medium tensile steels with a nominal tensile strength of 510 N/mm 2. The wire produces a deep penetrating arc reducing the risk of fusion related defects often associated with solid wires. Slag levels are minimal, often allowing multi - pass welding without inter - pass de - slagging. Dip transfer positional welding is carried out with the 1.0mm 1.2mm and 1.4mm sizes. Shielding gas Ar + 20% CO 2 Classification AWS A/SFA E70C-3M EN 758:1997 T 42 0 M M 2 H10 Applications All general fabrication in mild and medium tensile steels, usually exceeding 3mm thick for semi-automatic operation. Thinner material may be welded with automation including robots. Welding data DC electrode negative Dia Welding Current Volts mm positions Amps 1.0 F.H.V.O F.H.V.O F.H.V.O F.H F.H Typical weld metal composition C Si Mn Mechanical properties - All weld metal specimens Typical Minimum Yield stress 470 N/mm N/mm 2 Tensile Strength 550 N/mm N/mm 2 Elongation 28% 22% Charpy V impact values Test temp Typical Minimum 0 O C 12OJ 47J Approvals ABS 2SA,2YSA BV SA2YMH DNV llyms HH LR 2S,2YS,H15 GL 2YHHS Co CDS 0115 DS E51 2M (H) DB TUV 4311 OK Tubrod A metal cored tubular wire formulated for use with both Ar/CO 2 mixtures or CO 2 shielding gases. All the attributes associated with the Ar rich shielded 14.0X range are retained using either gas, although the use of CO 2 will reduce overall fabrication costs. Improvements in productivity weld quality and reduced spatter are readily achieved when compared with solid wire under CO 2. It is especially suitable for fillet welding and has a high tolerance to primer. Shielding gas CO 2 or Ar + 20% CO 2 Classification AWS A/SFA E70C-6M, E70C-6C EN 758:1997 T 42 2 M M 1 H10 T 42 2 M C 1 H10 Applications All general fabrications of mild and medium tensile steels with a nominal tensile strength not exceeding 510 N/mm 2 using single or multi-pass techniques. Welding data DC electrode negative Dia Welding Current Volts mm positions Amps 1.0 F.H.V.O F.H.V.O F.H.V.O F.H F.H Typical weld metal composition C Si Mn Mechanical properties - All weld metal specimens Typical Minimum Yield stress 470 N/mm N/mm 2 Tensile strength 550 N/mm N/mm 2 Elongation 28% 22% Charpy V impact values Test temp Typical Minimum -20 O C 100J 54J Approvals CO 2 Ar+20%CO 2 ABS 3SA, 3YSA 3SA, 3YSA BV SA3YM SA3YM DNV 111YMS 111YMS LR 3S, 3YS 3S 3YS GL 3YS DS E51 3M(H) E513M(H) RINa SG52-3 SG52-3 DB TUV OK Tubrod A metal cored tubular wire particularly suited to the rapid welding of fillet and butt joints in the flat and horizontal positions. Slag levels are comparable to those of solid wire and so ensures that this wire is also ideally suited for robotic and automated production. The arc action is stable at all current levels which provides for an excellent weld appearance with absence of undercut and spatter. Shielding gas Ar + 20% CO 2 Classification AWS A/SFA E70C-6M EN 758:1997 T 42 2 M M 2 H10 Applications The spray transfer welding of repetitive fillet and butt joints in mass production situations. Industries that would benefit from such a wire will be shipbuilding, Structural steel, general fabrication, agricultural machinery, rolling stock and automotive components. Welding data DC electrode positive Dia Welding Current Volts mm positions Amps 1.2 F.H.V.O F.H.V.O F.H Typical weld metal composition C Si Mn Mechanical properties - All weld metal specimens Typical Minimum Yield stress 480 N/mm N/mm 2 Tensile strength 580 N/mm N/mm 2 Elongation 28% 22% Charpy V impact values Test temp Typical Minimum -20 O C 90J 54J Approvals ABS 3SA, 3YSA BV SA3 YM DNV 111YMS LR 3S.3YS GL 3YS DB

6 OK Tubrod A metal cored tubular wire containing Cu especially for the welding of Corten A & B and similar weathering steels or other high tensile structural steels with a tensile strength up to 510 N/mm 2. Shielding gas Ar + 20% CO 2 Metal Recovery 95% Classification AWS A/SFA E70C-GM EN 758:1997 T 42 0 Z M M 2 H10 Applications Bridge and general structural steelwork, ships and chimneys. Welding data DC electrode negative Dia Welding Current Volts mm positions Amps 1.2 F.H.V.O F.H.V.O F.H Typical weld metal composition C Si Mn Cu Mechanical properties - All weld metal specimens Typical Minimum Yield stress 470 N/mm N/mm 2 Tensile Strength 550 N/mm N/mm 2 Elongation 28% 22% Charpy V impact values Test temp Typical Minimum 0 O C 130J 54J Approvals DS E51 3M (H) OK Tubrod A metal cored tubular wire similar to with an addition of Mo for use on high tensile and quenched and tempered steels with tensile strengths up to 550 N/mm 2. Shielding gas Ar + 20% CO 2 Metal recovery 95% Classification AWS A/SFA E80C-G EN 758:1997 T 50 2 Z M M 2 H10 Applications Marine structures, heavy machinery and high strength applications requiring good notch ductility. RQT 500, 600 Hyplus 29 DUCOL W30 OX602 Welding data DC electrode negative Dia Welding Current Volts mm positions Amps 1.2 F.H.V.O F.H Typical weld metal properties C Si Mn Mo Mechanical properties - All weld metal specimens Typical Minimum Yield stress 580 N/mm N/mm 2 Tensile Strength 650 N/mm N/mm 2 Elongation 26% 22% Charpy V impact values Test temp Typical Minimum -20 O C 65J 47J OK Tubrod A metal cored tubular wire alloyed with nickel and molybdenum to provide extra high strength with good notch ductility down to -40 O C. A 1.2 and 1.4mm size is available to cater for out of position welding. Shielding gas Ar + 20% CO 2 Metal recovery 95% Classification AWS A/SFA E111T-G Applications Offshore jack-up structures and general structural fabrication of high tensile steels for low temperature service. RQT 700 T1 HY80 Q1N. Welding data DC electrode negative Dia Welding Current Volts mm positions amps 1.2 F.H.V.O F.H.V.O F.H Typical weld metal composition C Si Mn Ni Mo Mechanical properties - All weld metal specimens Typical Minimum Yield stress 750 N/mm N/mm 2 Tensile Strength 830 N/mm N/mm 2 Elongation 23% 15% Charpy V impact values Test temp Typical Minimum -40 O C 70J 47J Approvals DB TUV 4143 MRS 5YMS HH

7 OK Tubrod A metal cored tubular wire containing nickel for applications involving service down to -60 O C. Available in a range of sizes to maximise versatility including a positional capability with a high resistance to cracking on heavy plate. Shielding gas Ar + 20% CO 2 Metal Recovery 95% Classification AWS A/SFA E70C-G EN 758:1997 T Ni M M 2 H10 Applications All general fabrication and structural steelwork including offshore equipment where sub-zero impact properties are of prime importance. Welding data DC electrode negative Dia Welding Current Volts mm positions Amps 1.2 F.H.V.O F.H.V.O F.H Typical weld metal composition C Si Mn Ni Mechanical properties - All weld metal specimens Typical Minimum Yield stress 480 N/mm N/mm 2 Tensile Strength 580 N/mm N/mm 2 Elongation 28% 22% Charpy V impact values Test temp Typical Minimum -60 O C 90J 47J Approvals ABS 3SA,3YSA BV UPHH KV-60 DNV lll YMS HH NV 2-4, NV 4-4 LR 3S 5Y40S H15 GL 6YH10S DS E51 5M (H) MRS 5YMSHH -60 TUV 4298 OK Tubrod A metal cored tubular wire offering similar characteristics to Tubrod but containing 1%Ni for the attainment of good notch toughness down to -40 O C. It is produced in a wide range of sizes including a 1.0mm which is ideal for root passes when used for one sided welding. All sizes are capable of positional welding using the dip transfer mode. Shielding gas Ar + 20% CO 2 Metal Recovery 95% Classification AWS A/SFA E70C-G EN 758:1997 T Ni M M 2 H10 Applications All structural and general fabrication work requiring good charpy V notch properties down to -40 O C. Welding data DC electrode negative Dia Welding Current Volts mm positions Amps 1.0 F.H.V.O F.H.V.O F.H.V.O F.H Typical weld metal composition C Si Mn Ni Mechanical properties - All weld metal specimens Typical Minimum Yield stress 460 N/mm N/mm 2 Tensile Strength 550 N/mm N/mm 2 Elongation 26% 22% Charpy V impact values Test temp Typical Minimum -40 O C 100J 47J Approvals ABS 3SA,3YSA BV SA3YM HH KV-40 DNV IIIYMS HH LR 3S 4Y40S H15 DS E51 5M (H) OK Tubrod A metal cored tubular wire containing Ni and Mo for use on high tensile as well as quenched and tempered steels with a minimum yield strength of 550 N/mm 2. The composition also ensures that this wire can be used on applications requiring good notch toughness down to -40 O C. Shielding gas Ar + 20% CO 2 Metal Recovery 95% Classification AWS A/SFA E91T-G Applications Off-road contractors plant, rail rolling stock, marine and bridge structures and similar items where high strength and good notch toughness is required. RQT 500, 600 DUCOL W30 OX 602 Welding data DC electrode negative Dia Welding Current Volts mm positions amps 1.2 F.H.V.O Typical weld metal composition C Si Mn Mo Ni Mechanical properties - All weld metal specimens Typical Minimum Yield stress 620 N/mm N/mm 2 Tensile Strength 700 N/mm N/mm 2 Elongation 24% 20% Charpy V impact values Test temp Typical Minimum -40 O C 70J 47J

8 OK Tubrod self-shielded range OK Tubrod A self-shielded flux cored tubular wire designed for all-positional welding of mild and medium tensile steels. It can be used for single or multi-pass welding and is equally suitable for flat and drooping characteristic power sources. Classification AWS A/SFA E71T-7 EN 758:1997 T 38 Z W N 2 Applications On-site general fabrication and structural work, with steels having a nominal tensile strength not exceeding 510 N/mm 2 and no impact requirements. Welding data DC electrode negative Dia Welding Current Volts mm positions amps 1.2 F.H.V.O F.H.V.O Typical weld metal composition C Si Mn Mechanical properties - All weld metal specimens Typical Minimum Yield stress 450 N/mm N/mm 2 Tensile Strength 555 N/mm N/mm 2 Elongation 26% 22% OK Tubrod A self-shielded flux cored tubular wire designed for the single and multi-pass welding of mild and medium tensile steels in the flat and HV positions. Capable of high deposition rates, it is ideal for general fabrication work where atmospheric conditions have to be tolerated. Classification AWS A/SFA E70T-4 Applications Site welding of general and structural steelwork with steels not exceeding 510 N/mm 2 tensile strength. Welding data DC electrode positive Dia Welding Current Volts mm positions amps 1.6 F.H F.H Typical weld metal composition C Si Mn Mechanical properties - All weld metal specimens Typical Minimum Yield stress 440 N/mm N/mm 2 Tensile Strength 600 N/mm N/mm 2 Elongation 26% 22%

9 OK Tubrod flux cored range OK Tubrod A rutile flux cored tubular wire principally designed for rapid fillet welding in the HV position. It is characterised by a very thin slag cover which, together with special formulation, affords a high tolerance to shop primer and is seen as a particular benefit to shipbuilders. The rutile base provides for a flat, extremely attractive weld appearance. Shielding gas CO 2 Classification AWS A/SFA E70T-1 EN 758:1997 T 42 0 R C 3 H10 Applications All general fabrication of mild and medium tensile steels. It is especially suited to shipbuilding, structural steel work, bridges, dumper bodies, etc where fillet welding predominates Welding data DC electrode positive Dia Welding Current Volts mm positions amps 1.2 F.H F.H F.H Typical weld metal composition C Si Mn Mechanical properties - All weld metal specimens Typical Minimum Yield stress 510 N/mm N/mm 2 Tensile Strength 570 N/mm N/mm 2 Elongation 28% 22% Charpy V impact values Test temp Typical Minimum 0 O C 80J 54J Approvals ABS 2SA 2YSA BV SA2YM HH DNV IIYMS H10 LR 2S 2YS H10 GL 2YH10S OK Tubrod A rutile flux cored tubular wire designed especially for heavy deposition in the flat and horizontal positions on mild and medium tensile steels up to 510 N/mm 2 tensile strength. Slag removal is easy and generally self-releasing. The weld appearance is exceptional and spatter level minimal. Shielding gas CO 2 Classification AWS A/SFA E70T-1 EN 758:1997 T 42 0 R C 3 H10 Applications Mass production situations demanding heavy deposition such as contractors plant, bed plates and pit-props in steel thicknesses of 9mm upwards. Welding data DC electrode positive Dia Welding Current Volts mm positions amps 1.2 F.H.V.O F.H F.H F.H F.H Typical weld metal composition C Si Mn Mechanical properties - All weld metal specimens Typical Minimum Yield stress 520 N/mm N/mm 2 Tensile Strength 580 N/mm N/mm 2 Elongation 26% 22% Charpy V impact values Test temp Typical Minimum 0 O C 90J 47J Approvals ABS 2SA BV SA2,2YM DNV llyms LR 2S,2YS GL 2YS Co CDS 0880 DS E51 2R (H) DB TUV 4211 OK Tubrod A flux cored tubular wire intended for applications requiring the highest possible deposition rates and also suitability for fully mechanised welding. It has a high efficiency at 87% and can deposit in excess of 8kgs/hr at 450A. It is designed for welding mild and medium tensile steels having a nominal tensile strength of 500 N/mm 2 in both the flat and HV positions. Used with CO 2 shielding the arc action is extremely stable producing an attractive weld finish with self releasing slag and low spatter. Shielding gas CO 2 Classification AWS A E70T-1 EN 758:1997 T 42 0 R C 3 H10 Applications Repetition welding of >12mm plate where heavy deposition is important, using either single or multi-pass welding techniques. Welding data DC electrode positive Dia Welding Current Volts mm positions amps 2.4 F.H Typical weld metal composition C Si Mn Ni Mechanical properties - All weld metal specimens Typical Minimum Yield stress 510 N/mm N/mm 2 Tensile Strength 580 N/mm N/mm 2 Elongation 28% 22% Charpy V impact values Test temp Typical Minimum -20 O C 50J 27J

10 OK Tubrod A rutile flux cored tubular wire designed for high deposition welding in the flat and HV positions. It is characterised by an exceptional weld finish with minimal spatter and self releasing slag using either Argon rich or CO 2 shielding gases. Approved to grade 2 and manufactured in four sizes for maximum versatility, this wire is capable of single and multi-pass welding of fillet and butt joints in mild and medium tensile steels with a nominal tensile strength of 510 N/mm 2. Shielding gas Ar + 20% CO 2 or CO 2 Classification AWS A/SFA E70T-1M, E70T-1 EN 758:1997 T 42 0 R C 3 H10 T 42 0 R M 3 H10 Applications All general fabrication of medium to heavy sections where weld appearance and high weld metal integrity is important. This will include bogie frames for railway rolling stock, contractors plant, bedplates, structural steelwork, bridge construction and shipbuilding. Welding data DC electrode positive Dia Welding Current Volts mm positions Amps 1.2 F.H.V.O F.H F.H Typical weld metal composition C Si Mn Mechanical properties - All weld metal specimens Typical Minimum Yield stress 500 N/mm N/mm 2 Tensile Strength 560 N/mm N/mm 2 Elongation 28% 22% Charpy V impact values Test temp Typical Minimum 0 O C 70J 54J Approvals Ar + 20% CO 2 CO 2 ABS 2SA,2YSA 2SA,2YSA BV SA2YM SA2YM DNV IIYMS IIYMS LR 2S, 2YSH15 2S, 2YSH15 DS E51 3R(H) E51 3R(H) DB TUV OK Tubrod A rutile flux cored tubular wire for all positional welding using either Ar/CO 2 or CO 2 shielding gases. This wire is suitable for all mild and medium tensile structural steels with tensile strengths up to 510 N/mm 2. Running characteristics are exceptional, using the spray mode of transfer, and applies equally to both shielding gases. OK Tubrod is also universally approved to grade 3 by all major authorities. Shielding gas Ar + 20% CO 2 or CO 2 Classification AWS: A E71T-1M, E71T-1 EN 758:1997 T 46 2 P M 2 H10 T 46 2 P C 2 H10 Applications All general fabrication including multipositional welding of fillet and butt joints. This will include shipbuilding, selected offshore segments, automated pipe welding and heavy fabrication where rotation of the work to the downhand position is impractical. It is also excellent for one sided welding in conjunction with non-fusible backing. Welding data DC electrode positive Dia Welding Current Volts mm positions amps 1.2 F.H.V.O F.H.V.O F.H.V.O Typical weld metal composition C Si Mn Mechanical properties - All weld metal specimens Typical Minimum Yield stress 530 N/mm N/mm 2 Tensile strength 580 N/mm N/mm 2 Elongation 26% 22% Charpy V impact values Test temp Typical Minimum -20 O C 120J 54J Approvals Ar/CO 2 CO 2 ABS 3SA,3YSA 3SA,3YSA BV SA3YM SA3YM DNV lllyms lllyms LR 3S,3YS 3S,3YS GL 3YS 3YS Co CDS 1185 DS E51 3R(H) RINa SG 52.3 SG 52.2 DB MRS 3S 3YS 3S 3YS OK Tubrod A rutile flux cored tubular wire designed as a truly all-positional general purpose wire for welding mild and medium tensile steels up to 510 N/mm 2 tensile strength. Using either type of shielding gas the 1.2 and 1.4mm sizes can be used in the vertical position on spray transfer providing for maximum deposition and time savings. Weld pool control is easy both vertically up and downwards and slag removal is rapid. In addition all sizes are approved to Grade 3. Shielding gas Ar + 20% CO 2 or CO 2 Classification AWS A/SFA E71T-1M, E71T-1 EN 758:1997 T 46 2 P C 2 H10 T 46 2 P M 2 H10 Applications General purpose welding of large fabrications in situ. Ideal in situations where manipulation of the work is not practical. Welding data DC electrode positive Dia Welding Current Volts mm positions Amps 1.2 F.H.V.O F.H.V.O F.H.V.O Typical weld metal composition C Si Mn Mechanical properties - All weld metal specimens Typical Minimum Ar + 20%CO 2 Yield stress 520 N/mm N/mm 2 Tensile Strength 580 N/mm N/mm 2 Elongation 28% 22% Charpy V impact values Test temp Typical Minimum -20 O C 140J 54J Approvals CO 2 Ar + 20% CO 2 ABS 3SA,3YSA 3SA,3YSA BV SA3,3YM SA 3YM DNV lllyms lllyms LR 3S,3YS H15 3S,3YS H15 GL 3YHHS 3YHHS Co CDS 0390 CDS 0390 DS E51 3R(H) E51 3R(H) MRS 3YMSHH 3YMSHH DB TUV

11 OK Tubrod A rutile tubular wire for welding of structural steels with a nominal tensile strength of 550 N/mm 2 and in all positions. Particularly for use where good sub-zero toughness is required down to -40 O C. Shielding gas Argon + 20% CO 2 Classification AWS A/SFA E81T1-Ni1 EN 758:1997 T Ni P C 2 H5 (H10 1.6mm) T Ni P M 2 H5 (H10 1.6mm) Applications Areas of application are primarily in the offshore, structural steel and shipbuilding industries. Eminently suitable for open butt joints using non-fusible backing materials. Welding data DC electrode positive Dia Welding Current Volts mm positions Amps 1.2 F.H.V.O F.H.V.O F.H.V.O Typical weld metal composition C Si Mn Ni Mechanical properties - All weld metal specimens Typical Minimum Yield stress 560 N/mm N/mm 2 Tensile Strength 600 N/mm N/mm 2 Elongation 25% 22% Charpy V impact values Test temp Typical Minimum -40 O C 130J 75J Approvals Ar + 20% CO 2 CO 2 ABS 3SA,3YSA 3SA,3YSA BV SA 3YM SA 3YM HH DNV lllyms HH LR 3S, 4Y40S H15 3S, 3YS, H15 DS E51 5R(H) E51 5R(H) MRS 4YMSH(-40) TUV 5198 DB OK Tubrod A rutile all positional flux cored tubular wire containing 2.5% Ni for the welding of mild and medium tensile steels where good notch toughness down to -50 O C is required. Extra productivity is available via the use of the spray transfer mode when compared to the traditional basic types using short arc for vertical and overhead welding. Shielding gas Ar + 20% CO 2 Classification AWS A/SFA E81T1-Ni2 EN 758:1997 T Ni P M 2 H5 Applications All types of fabrication involving mild and medium steels having a minimum yield strength of 490 N/mm 2 and toughness requirements down to -60 O C. This will include shipbuilding and offshore fabrication. Welding data DC electrode positive Dia Welding Current Volts mm positions Amps 1.2 F.H.V.O Typical weld metal composition C Si Mn Ni Mechanical properties - All weld metal specimens Typical Minimum Yield stress 580 N/mm N/mm 2 Tensile Strength 620 N/mm N/mm 2 Elongation 24% 20% Charpy V impact values Test Temp Typical Minimum -50 O C 95J 50J Approvals DNV H NV E460 OK Tubrod A rutile type flux cored tubular wire especially formulated to produce high yield strength and good sub-zero fracture toughness with an all-positional welding capability using spray transfer. The weld metal composition is controlled to ensure a minimum yield strength of 550 N/mm 2 and good toughness down to -50 O C. Shielding gas Ar + 20% CO 2 Classification AWS A/SFA E81T1-Ni1 Applications General fabrication of high strength C-Mn and low alloy steels in all positions. Ideally suitable for quenched and tempered steels such as HY80 and Q1N. Welding data DC electrode positive Dia Welding Current Volts mm positions amps 1.2 F.H.V.O Typical weld metal composition C Si Mn Ni Mechanical properties - All weld metal specimens Typical Minimum Yield stress 620 N/mm N/mm 2 Tensile Strength 650 N/mm 2 Elongation 24% Charpy V impact values Test temp Typical Minimum -50 O C 95J 70J

12 OK Tubrod A fully basic flux cored tubular wire producing low hydrogen quality weld metal with a high resistance to cracking under conditions of restraint. A 1.2mm size is available for positional welding using the dip transfer mode, while the 1.6mm and 2.4mm sizes permit heavy deposition in the downhand position. The slag cover is thin and easily re-melted eliminating inter-run deslagging in some cases. Shielding gas Ar + 20% CO 2 or CO 2 Metal Recovery 90% Classification AWS A/SFA E71T-5M, E71T-5 EN 758:1997 T 42 3 B M 2 H5 T 42 3 B C 2 H5 Applications All general fabrication work involving the multi pass welding of heavy sections in tensile strength up to 510 N/mm 2. Welding data DC electrode negative Dia Welding Current Volts mm positions Amps 1.0 F.H.V.O F.H.V.O F.H.V.O F.H F.H F.H Typical weld metal composition C Si Mn Mechanical properties - All weld metal specimens Typical Minimum Yield stress 470 N/mm N/mm 2 Tensile Strength 550 N/mm N/mm 2 Elongation 30% 22% Charpy V impact values Test temp Typical Minimum -20 O C 135J 54J -30 O C 120J 47J Approvals CO 2 Ar + 20% CO 2 ABS 3SA,3YSA - BV SA3MH - DNV lllyms lllyms LR 3S,3YS H15 3S,3YS H15 GL 3YHHS 3YHHS Co CDS 0485 CDS 0485 DS E15 3B(H) E15 3B(H) MRS 3YMSHH DB TUV RINa SG52-3 SG52-3 OK Tubrod A fully basic flux cored tubular wire for the all position welding of mild and medium tensile steels including vertical down. It has particularly stable running characteristics at low current levels which enhances operability and minimises spatter. The arc action is such that penetration is good and together with the basic slag system ensures that this wire has a high tolerance to plate condition and shop primer. Shielding gas Ar + 20% CO 2 Classification AWS A/SFA E71T-5M EN 758:1997 T 42 3 B M 2 H5 Applications All general fabrication using either single or multi - pass techniques for fillet and butt joints where the combined effect of restraint and hydrogen must be minimised. Industries would include ship and bridge building, heavy pipe fabrication and marine structures. Welding data DC electrode negative Dia Welding Current Volts mm positions Amps 1.2 F.H.V.O F.H.V/D Typical weld metal composition C Si Mn Mechanical properties - All weld metal specimens Typical Minimum Yield stress 450 N/mm N/mm 2 Tensile Strength 550 N/mm N/mm 2 Elongation 30% 22% Charpy V impact values Test temp Typical Minimum -30 O C 130J 47J Approvals DNV III YMS H5 LR 3S 3YS H5 GL 3Y H5S OK Tubrod A fully basic flux cored tubular wire producing 1% Ni weld metal. It combines high strength with low temperature toughness for service down to -50 O C and has good CTOD performance. This applies to both the as-welded and stress relieved condition. Used with either mixed gas or CO 2 it has a high tolerance to plate condition with good operability and slag release. Shielding gas Ar + 20% CO 2 or CO 2 Classification AWS A/SFA E80T5-G EN 758:1997 T 46 5 Z B M 2 H5 Applications All structural and general fabrication where a minimum yield strength of 470 N/mm 2 is required and for service down to -50 O C. Applications will involve such steels as 450 EMZ which find popular use in the offshore industry. Welding data DC electrode negative Dia Welding Current Volts mm positions Amps 1.0 F.H.V.O F.H.O F.H.V Typical weld metal composition C Si Mn Ni Mechanical properties - All weld metal specimens Typical Minimum Yield stress 540 N/mm N/mm 2 Tensile strength 600 N/mm N/mm 2 Elongation 28% 22% Charpy V impact values Test temp Typical Minimum -50 O C 120J 47J

13 OK Tubrod A fully basic flux cored tubular wire containing approximately 2.5% nickel for welding a wide variety of structural work in all positions for service down to -60 O C. The scope for applications is increased further by the excellent CTOD performance at -10 O C. While the 1.6mm size will give most acceptable deposition rates in the flat and H.V. positions. The 1.2mm can be used in the vertical and overhead positions using dip transfer. Shielding gas CO 2 or Ar + 20% CO 2 Classification AWS A E70T5-G EN 758:1997 T Ni B M 2 H5 Applications All fabrication work involving thick sections under restraint and required for service at low temperatures. Offshore platforms, pressure vessels and bridges. Welding data DC electrode negative Dia Welding Current Volts mm positions Amps 1.2 F.H.V.O F.H Typical weld metal composition C Si Mn Ni Mechanical properties - All weld metal specimens Typical Minimum Yield stress 480 N/mm N/mm 2 Tensile Strength 570 N/mm N/mm 2 Elongation 30% 22% Charpy V impact values Test temp Typical Minimum -60 O C 100J 47J Approvals DNV lllyms HH NV2-4 NV4-4 LR 3S, 5Y40, H15 Co CDS 0551 TUV 4299 OK Tubrod A fully basic flux cored tubular wire for welding high strength steels for service at both ambient and sub-zero temperatures down to -50 O C. The weld metal has a minimum yield strength of 570 N/mm 2 and is ideal for situations involving high levels of restraint and where the deleterious effects of hydrogen must be avoided. Shielding gas Ar + 20% CO 2 Classification AWS A/SFA E90T5-K2 Applications A wide range of structures using high tensile steels such as HY80, OX540E, OX542, OX602, and DOMEX 480. Cranes, earth moving plant, and offshore marine jack-up type platforms are typical examples. Welding data DC electrode negative Dia Welding Current Volts mm positions Amps 1.2 F.H.V.O F.H Typical weld metal composition C Si Mn Ni Mechanical properties - All weld metal specimens Typical Minimum Yield stress 620 N/mm N/mm 2 Tensile strength 690 N/mm N/mm 2 Elongation 24% 17% Charpy V impact values Test temp Typical Minimum -50 O C 100J 70J OK Tubrod A fully basic flux cored tubular wire for the welding of high strength steels such as HY100. The weld metal contains 2.5% Ni giving the additional benefit of low temperature toughness down to -50 O C. This wire is capable of welding in all positions and uses the dip transfer mode for the vertical-up technique, which can be further enhanced by the synergic pulsed process. Shielding gas Ar + 20% CO 2 Classification AWS A/SFA E110T5-G Applications The fabrication of high tensile steels with a yield strength in the region of 700 N/mm 2. Such steels will include HY100, RQT701 and Weldex 812EM, all of which find applications in submarines, cranes, jack-up marine structures etc. Welding data DC electrode negative Dia Welding Current Volts mm priorities Amps 1.2 F.H.V.O F.H Typical weld metal composition C Si Mn Ni Mechanical properties - All weld metal specimens Typical Minimum Yield stress 750 N/mm N/mm 2 Tensile strength 820 N/mm N/mm 2 Elongation 21% 15% Charpy V impact values Test temp Typical Minimum -50 O C 80J 50J

14 OK Tubrod A fully basic flux cored tubular wire containing 1.25% Cr and 0.5% Mo designed for welding creep resisting steels of similar composition. High deposition rates are enhanced by the addition of metal powder to the core and the weld metal produced is of exceptional metallurgical quality. Shielding gas CO 2 or Ar + 20% CO 2 Classification AWS A/SFA E80T5-B2 Applications All creep resisting steels of similar composition and most commonly used in process plant and the power generation industry at service temperatures in the region of 500 O C. Recommendations for welding Preheating at O C is necessary followed by post weld heat treatment of O C. Welding data DC electrode negative Dia Welding Current Volts mm positions Amps 1.2 F.H.V.O F.H Typical weld metal composition C Si Mn Cr Mo Mechanical properties - All weld metal specimens Stress relieved (690 O C 1HR) Yield stress 570 N/mm 2 Tensile strength 670 N/mm 2 Elongation 22% OK Tubrod A fully basic flux cored tubular wire containing 2.25% Cr and 1.0% Mo for welding creep resisting steels of similar composition and intended for service at temperatures in the region of 600 O C. The weld metal produced is of low hydrogen and very high metallurgical and radiographic standard. A pre-heat and interpass temperature of 250 O C followed by a post weld heat treatment of 670 O C- 710 O C is essential for good results. The 1.2mm size is ideal for positional welding using the dip or controlled dip modes of transfer. Shielding gas CO 2 or Ar + 20% CO 2 Classification AWS A/SFA E90T5-B3 Applications Process and power generation plant and welded fabrication involving steels of similar composition for service at elevated temperatures. Boilers, pressure vessels and piping. Welding data DC electrode negative Dia Welding Current Volts mm positions Amps 1.2 F.H.V.O F.H Typical weld metal composition C Si Mn Cr Mo Mechanical properties - All weld metal specimens Stress relieved (690 O C 1HR) Yield stress 570 N/mm 2 Tensile strength 680 N/mm 2 Elongation 26%

15 OK Tubrod stainless cored wires Traditionally the most popular processes for the welding of stainless steels have been manual arc followed by MIG, TIG and submerged arc. Solid wire is faster than manual arc, but can lack appeal due to spatter levels, a heavily oxidised weld deposit or fusion defects related to low current positional welding using dip transfer. Obviously, the use of TIG and submerged arc will continue due to their particular attributes for certain applications. The rapidly developing range of cored wires, however, which include types for Duplex steels offer the fabricator a genuine opportunity for increased quality and productivity over solid wire MAG and manual arc electrodes. The benefits can be summarised as: Up to 30% increase in weld metal deposition rate over solid wire and four times that of manual arc, hence faster welding speeds which in turn reduce distortion. Two ranges of wires to permit welding of all the popular grades of stainless steels both for the downhand and out of position welding. Moisture regain is minimal ensuring that start porosity is eliminated. The rutile types are designed for use with Ar/CO 2 or CO 2 shielding gas. The latter serves to reduce gas costs and radiated heat is also significantly lower giving greater operator comfort. Individual batch testing of weld metal composition means that the most stringent of quality standards are met. OK Tubrod 14.2X Series The range of wires within the OK Tubrod 14.2X series have been especially designed to produce superior operability for all-positional welding applications. Regardless of position, the weld deposit will be flat, which is a quality provided by the faster freezing slag. In having a rutile based slag system they always operate in the spray transfer mode and can be used at high currents and hence give high deposition rates. Slag release problems do not exist even in V butt joints and when not totally self releasing, the slag can be removed with the very minimum of chipping. As can be expected from these types of wire, the spatter levels are almost non-existent allowing additional savings in cleaning time. This is afforded by the extremely stable arc action under spray transfer conditions which ensures that the maximum possible efficiency is being achieved from the wire. Across the two sizes and within their recommended current ranges, efficiency will vary from a minimum of 81.5% up to 84%. Two sizes, 0.9mm and 1.2mm are available for most wires within the OK Tubrod 14.2X series and together they can handle a very wide field of application. With regard to productivity, the 1.2mm types are in excess of three times faster than 3.2mm manual arc electrodes and almost twice as fast as 0.9mm solid wires in the vertical position. Refer to OK Tubrod deposition rates page 27. Productivity OK 14.2X OK 14.2X 6mm Vertical up Fillet Joint (6mm throat = 0.33kg weld metal/metre) Process Size Amps Kgs/Arc Arc Time Hour mins/m MMA AWS: E308L Solid Wire MIG (Dip Transfer) AWS: ER308L Cored Wire MIG/MAG OK (AWS E308LT-1) Length of completed joint per hour - Duty Cycle 20% MMA Solid MIG OK = 0.8 Metres = 1.3 Metres = 3.5 Metres OK Tubrod 14.3X Series It is not possible to produce a consumable that operates with equal performance in every situation and the OK Tubrod 14.3X range was introduced especially for welding in the flat and horizontal vertical positions. This range complements the OK Tubrod 14.2X range by designation and composition to produce an exceptional partnership for stainless steel welding. The OK Tubrod 14.3X series can in fact be used for vertical upwards welding, but their more fluid slag, which is for optimum downhand operation, does impose certain limitations. Single pass or narrow deposits are not possible using the vertical-up technique due to excessive heat build up. The weaving technique is excellent on thicker plate when there is greater heat sink and additional dissipation from the weaving. Single passes for fillet welding and the root areas of butt joints should be completed using the vertical downwards technique, but there is the attendant reduction in depth of penetration. This technique is restricted to the 1.2mm sizes, and can also be used to advantage for rapid welding of sheet material. The operability of the OK Tubrod 14.3X wires is exceptional combining extreme ease of use, high performance with regard to metal deposition and a weld appearance comparable to the latest generation of manual arc electrodes. As with rutile based C/Mn types the spray transfer mode is used at all acceptable current levels even down to 100A with the 1.2mm size. Such a facility affords high welding speeds, reduced operator fatigue, better fusion and a low risk of defects when compared to solid wire. Although normally used at higher current levels than the OK Tubrod 14.2X series, spatter is still virtually non-existent and the thin slag is generally self releasing leaving a bright smooth weld finish. This is an obvious advantage on fabrications where subsequent dressing and polishing is required, especially in the case of fillet joints. Moisture regain is not a problem as is sometimes the case with manual arc electrodes when start porosity can occur. In tests at 30 O C and a relative humidity of 80% OK Tubrod 14.2X and 14.3X wires gave an increase in moisture of 0.5% after four weeks. This compares with 0.7% after two weeks for moisture resistance manual electrodes and 3% for standard electrodes, Fig 1. Fig 1 Moisture absorption rate (%) Storage period - weeks 80%RH 30 O C 50%RH 20 O C

16 Productivity HV Fillet Joint (5mm throat = 0.25 kg weld metal/metre) OK 14.3X OK 14.3X Process Size Amps Kgs/Arc Arc Time 5mm Length of completed joint per hour - Duty Cycle 20% MMA Solid MIG OK Hour mins/m MMA AWS: E316L Solid Wire MIG AWS: ER316L Cored Wire MIG/MAG OK (AWS E316LT-1) = 2.08 Metres = 3.12 Metres = 4.64 Metres Shielding gases A variety of shielding gases can be used with the flux cored types due to the greater tolerance available, although the higher the CO 2 content the higher the carbon content and the lower the alloy and ferrite content. However, the changes are marginal with C increasing by 0.01% and Cr decreasing by 0.1% progressively between pure Ar through to pure CO 2. The influence of shielding gas on mechanical properties is also minimal to the extent that the changes may be disregarded. With regard to running characteristics the CO 2 content should not be less than 20% as a lower content will produce inferior arc manipulation. Product specifications Flux cored - All Positional All Weld Metal Results (Ar + 20% CO 2 Shielding Gas) Designation Sizes Chemical Mechanical Classification Polarity mm Composition Properties A Approvals & Shielding Gas OK Tubrod C 0.03 Yield 400 N/mm 2 E308LT1-4 DC+ TÜV 1.2 Mn 1.1 UTS 590 N/mm 2 Ar/CO 2 Co Si 0.7 Elong 45% Cr 19.5 Charpy V Ni O C 32J OK Tubrod C 0.03 Yield 475 N/mm 2 E316LT1-4 DC+ TÜV 1.2 Mn 1.3 UTS 615 N/mm 2 Ar/CO 2 Co Si 0.9 Elong 36% DNV Cr 18.5 Charpy V GL Ni O C 26J LR Mo 2.5 OK Tubrod C 0.03 Yield 460 N/mm 2 E309LT1-4 DC+ TÜV 1.2 Mn 1.3 UTS 590 N/mm 2 Ar/CO 2 Co Si 0.9 Elong 37% DNV Cr O C 40J LR Ni 12.5 GL OK Tubrod C 0.03 Yield 475 N/mm 2 E317LT1-4 DC+ Mn 1.2 UTS 630 N/mm 2 Ar/CO 2 Si 0.9 Elong 34% Cr O C 40J Ni 12.5 Mo 3.5 OK Tubrod C <0.04 Yield 612 N/mm 2 E2209T1-1 DC+ DNV Mn 0.9 UTS 824 N/mm 2 E2209T1-4 CO 2 RINa Si 0.9 Elong 33% Ar/CO 2 TÜV Cr 22.0 Charpy V Co Ni O C 56J GL Mo 3.0 LR N 0.15 OK Tubrod C <0.04 Yield 650 N/mm 2 E2553T0-4 DC+ Mn 0.9 UTS 820 N/mm 2 Ar/CO 2 Si 0.6 Elong 18% Cr 25.0 Charpy V Ni O C 55J Mo O C 39J N 0.24

17 Flux Cored - Downhand Metal Cored All Weld Metal Results (Ar + 20% CO2 Shielding Gas) Designation Sizes Chemical Mechanical Classification Polarity mm Composition Properties A Approvals & Shielding Gas OK Tubrod C 0.03 Yield 390 N/mm 2 E308LTO-1 DC+ LR 1.6 Mn 1.6 UTS 560 N/mm 2 E308LTO-4 CO 2 TÜV Si 0.4 Elong 39% Ar/CO 2 DB Cr 19.0 Charpy V Ni O C 44J -196 O C 32J OK Tubrod C 0.03 Yield 410 N/mm 2 E316LTO-1 DC+ LR 1.6 Mn 1.4 UTS 570 N/mm 2 E316LTO-4 CO 2 TÜV Si 0.4 Elong 33% Ar/CO 2 DB Cr 19.0 Charpy V Ni O C 40J Mo O C 32J OK Tubrod C 0.03 Yield 449 N/mm 2 E309LTO-1 DC+ LR 1.6 Mn 1.6 UTS 594 N/mm 2 E309LTO-4 CO 2 TÜV Si 0.4 Elong 32% Ar/CO 2 DB Cr 24.0 Charpy V Ni O C 42J OK Tubrod C 0.03 Yield 526 N/mm 2 E309MoLTO-1 DC+ LR 1.6 Mn 1.6 UTS 672 N/mm 2 E309MoLTO-4 CO 2 RINa Si 0.4 Elong 34% Ar/CO 2 TÜV Cr 23.0 Charpy V Ni O C 44J Mo 2.3 OK Tubrod C 0.04 Yield 460 N/mm 2 E347TO-1 DC+ Mn 1.6 UTS 610 N/mm 2 E347TO-4 CO 2 Si 0.4 Elong 41% Ar/CO 2 Cr 19.0 Charpy V Ni O C 56J Nb 0.5 OK Tubrod C 0.02 Yield 360 N/mm 2 EC308L DC+ TÜV 1.6 Mn 1.4 UTS 570 N/mm 2 Si 0.7 Elong 45% Ar/2%CO 2 Cr 19.0 Charpy V Ar/2%O 2 Ni O C 70J FN 8 OK Tubrod C 0.02 Yield 400 N/mm 2 EC316L DC+ TÜV 1.6 Mn 1.4 UTS 600 N/mm 2 Si 0.7 Elong 37% Ar/2%CO 2 Cr 18.0 Charp V Ar/2%O 2 Ni O 45J Mo 2.7 FN 8 OK Tubrod C 0.03 Yield 380 N/mm 2 EC309L DC+ 1.6 Mn 1.3 UTS 570 N/mm 2 Si 0.6 Elong 34% Ar/2%CO 2 Cr 23.0 Charpy V Ar/2%O 2 Ni O C 45J FN 15 OK Tubrod C 0.1 Yield 425N/mm 2 EC307 DC+ TÜV 1.6 Mn 6.0 UTS 625N/mm 2 Ar/2%CO 2 Si 0.7 Elong 40% Ar/2%O 2 Cr 18.0 Charpy V Ni O C 40J OK Tubrod C 0.03 Yield 600N/mm 2 EC2209 DC+ 1.6 Mn 0.7 UTS 780N/mm 2 Ar/2%CO 2 Si 0.7 Elong 27% Ar/2%O 2 Cr 22.0 Charpy V Ni O C 50J Mo 3.0 N 0.13

18 Consumable selection OK Tubrod EN No AISI DIN BS970 SS } X 10 CrNi ,304 X 5 CrNi S X 5 CrNi L,347 X 2 CrNi S X 2 CrNi X 10 CrNiNb S X 6 CrNiNb X 6 CrNiTi S X 6 CrNiTi S } X 2 CrNiMo X 2 CrNiMo S X 3 CrNiMo , 316L X 5 CrNiMo S X 2 CrNiMo Ti X 2 CrNiMo S X 6 CrNiMoTi X 6 CrNiMoTi S S31 } X 6 Cr ,410 X 7 Cr13 403S X 12 Cr ,430 X 10 Cr13 410S X 20 Cr X 20 Cr13 420S X 6 Cr X 6 Cr17 430S X 2 CrNiMo L X 2 CrNiMo X 6 CrNiNb , 321 X 10 CrNiNb S X 6 CrNiTi X 6 CrNiTi S } Buffer layers Dissimilar welding Difficult to weld steels Austenitic manganese steels Corrosion and wear resistance Armour steels Duplex steels including SAF 2205, FAL 223, AF22, NK Cr22, HY Resist 22/ Super Duplex steels including SAF 2507, UR52N+, XERON 100

19 Robotic welding and cored wires Metal cored Traditionally robots offered an increase in duty cycle and a reduction in cycle time but not an increase in welding speed. Solid wire was universally accepted for economy, restriking ability and so on, but actual arcing time remained the same as that with semi automatic MIG/MAG welding. The introduction of metal cored wires has presented the robot user with an opportunity to gain an even greater and quicker return on the comparatively high investment cost. The increase in productivity afforded by metal cored wires are not restricted to semiautomatic equipment and such wires can be readily adapted to robots with no modifications. However, since some applications may benefit from a larger size than 1.2mm which is the most popular size, the fitting of water cooled torches may be necessary. The same may apply to 1.6mm in circumstances where higher currents than those used with the same size of solid wire are envisaged. At the opposite end of the scale and until recently solid wire was the only practical solution with gauge material, for such items as automotive components, office furniture, etc. The availability of 1.0mm metal cored wire has now all but equalled the scope of solid wire but with the added benefits of improved quality with higher productivity. Cycle time and productivity A reduction of 1% in total cycle time can make an enormous difference to annual production figures and usually gives an extra half week of output. Once the robot is installed it would be difficult to make a reduction in handling time, i.e. positioning of the work and speed of Deposition/Speed Evaluation travel between weld runs. Therefore any increase in welding speed is vital, since in most cases welding time is at least 60% of the total cycle time. For example if a component has 320cm of 4mm throat fillet and a 1.2mm solid wire is achieving this at 60cm/min then 5.3 minutes of the cycle is actual arcing time. A change to 1.6mm metal cored wire can achieve welding speeds of 84cm/min for the same size of fillet, which will reduce arcing time to 3.8 minutes and hence total cycle time from 6.0 minutes to 4.5 minutes. This represents a saving of 25% and a theoretical gain of 12 weeks production in a year. Alternatively, the situation can be viewed in terms of metres of weld per year. A 1.2mm solid wire with an arc time of 1.6 min/m and operating at 60% duty cycle for an 1800 hr/yr will produce 40,500 metres of 4mm T fillet. This compares with 54,450 metres for OK Tubrod mm at a travel speed of 1.19 min/m or an additional 13,950 metres per year. Summary - 4mm T Fillet Wire Solid Metal 1.2mm cored 1.6mm Weld speed cms/min Arc time mins Total cycle time mins Metres of weld/yr 40,500 54,450 Flux cored wires With regard to flux cored wires as against metal cored wires, some operators and also manufacturers are sceptical of using these due partly to the possibility of poor arc initiation. This is caused by beads of slag on the wire tip, which form between weld runs and cause an insulating effect. There is also the question of deslagging the welds on completion of a component and in the case of basic types the higher levels of spatter which add a further cost dimension in cleaning time. This is not to say that flux cored wires should be disregarded completely for robotic use as they are being used successfully in a variety of cases. Flux cored wires deposit weld metal at a faster rate than metal cored or solid wires especially the rutile EX0T-1 for downhand operation and the EX1T-1 types where positional welding is involved. Provided that the operating parameters are correct the slag from rutile types is self releasing, or if not will generally fall off when cold or through vibration with subsequent handling. Spatter levels will be minimal and restriking can be assisted with a creep feed starting system. The choice therefore depends on the circumstances but flux cored wires would be best suited to joints where larger volumes of weld metal are specified and/or when long uninterrupted run lengths are required. Marathon Pacs Non productive time can be minimised further by the use of bulk packs in the form of the Marathon Pac. Unlike any other pack of similar proportions the drum is loaded using a special production technique which ensures that the wire is delivered straight. Solid Wire E70S-6 Wire Dia Fillet Size Amps Volts Travel Speed Wire Feed Deposition Arc Time mm T L cms/min cms/min Rate kgs/hr mins/m OK Tubrod

20 Shielding gas Other types of pack or the standard 16kg reels are such that the wire flicks or twists once per revolution. This is a particular disadvantage for robots when the wire has to be in a precise position relative to the joint every time. A Marathon Pac can therefore reduce the incidence of defects and also maintenance as wear on equipment is minimal. At a nominal weight of 200 kg this represents a saving of about 13 normal 15/16 kg reel changes which at 10 minutes each is 2 hours 10 minutes. Considering the example previously described with a 4.5 minute cycle, this represents a further 28 components. A 300 kg pack is also available and using the same example, the time saved will allow production of a further 41 components. The case in point 30% increase in welding speed higher burn off rates than solid wire faster welding speed greater return on investment Superior weld finish obtained from spray transfer mode max tolerance to plate condition varying from positive to negative polarity excellent fusion and wetting action minimises defects and risk of undercut, even at high travel speeds argon rich gas minimises spatter level and gives optimum deposit appearance No restriking problems with metal cored wire there are no restriking problems with either a hot or cold wire tip applies to single and multipass applications Tolerance to variances greater flexibility than solid wire: one current setting may be used for wider variety of weld sizes/travel speeds greater tolerance to fit-up variations than solid wire, which can be critical if defects are to be avoided Greater economy greater penetration allows a reduction in fillet size for a given material thickness, leading to further overall cost benefits Single pass gravity fillet joint mm wire, 8mm throat thickness. Welding speed - 40cm/min. Single pass HV fillet joint - 1.6mm wire, 3mm throat thickness. Welding speed - 120cm/min. C/Mn & low alloy wires A variety of shielding gases are now in regular use for the MIG/MAG cored wire process and normally involve CO 2, Ar, O 2, and He. CO 2 is the only gas for use singularly but can be found in mixtures of all the others to bring about various welding characteristics, although Ar is always the principle gas when mixtures are employed. CO 2 gas This gas is normally referred to as an active gas as it is not chemically inert, hence the term MAG. It is the least expensive gas, but does have disadvantages when compared to Ar based types. Advantages: inexpensive low heat radiation superior depth to width ratio lower levels of diffusible hydrogen in the weld metal Disadvantages: higher levels of spatter narrow voltage band - machine setting is critical The majority of the OK Tubrod flux cored wires may be used with CO 2 only and produce good results. The fully basic wires such as OK Tubrod and will, in fact, produce superior physical characteristics when used with CO 2 only. Argon/CO 2 mixtures The most popular gas mixture both for C/Mn solid wire and cored wire is that of Argon % CO 2 and although it is more expensive, generally by a factor of three, the advantages certainly justify its use. Advantages: reduced spatter through smoother arc action lower fume generation superior weld finish and profile ability to support a wide voltage range - machine setting less critical consistent and more favourable penetration, especially with cored wires faster welding speeds Disadvantages: greater radiated heat water cooling sometimes required

21 Modes of weld metal transfer With the exception of OK Tubrod it is essential that all of the OK Tubrod metal cored wires be used with Ar rich gases as the use of CO 2 will result in a serious deterioration in weld appearance with unacceptable levels of fume and spatter. With regard to flux cored wires, all except OK Tubrod and may be used with Ar + CO 2 mixtures to enhance operability with reduced spatter and fume levels, but penetration will be decreased. O 2 and He additions Although principally used for the MIG welding of stainless steel, the O 2 to promote good wetting and He for additional heat as well as cleaning effect, caution should be exercised with O 2, for use with C/Mn and low alloy wires. O 2 is often mixed with Ar and CO 2, on a basis of 80% Ar, 15% CO 2, 5% O 2. Such a mixture imparts very good wetting and reduces the droplet size and surface tension of the weld metal. However, O 2 does have the effect of decreasing alloy transfer across the arc and it is particularly important to be aware of this during welding low alloy steels when a matching composition is required or in the case of Mn when tensile strength is critical. Effect on weld shape 100% Ar The economic advantages to be gained from the use of cored wires are obvious, but consideration should be given to the modes of metal transfer to achieve the maximum benefit, especially as direct comparisons with solid wire are not necessarily applicable. The choice of consumable and size relative to the proposed application are important aspects to be considered in exploiting the advantage of the process. Dip transfer When using standard constant voltage power sources the dip transfer mode will only occur at currents generally below 200A, although will vary depending upon wire size and parameters selected. This method of metal transfer relies on a series of short circuits where the wire actually touches down into the weld pool and consequently the current rises and melts off the end of the wire. Fig 2. A tapped inductance is usually available which can be used to vary the surge of current such that the eruptions taking place immediately after short circuiting do not cause excessive spatter. The dip or short arc method is characterised by a cool arc and so is ideal for sheet material, root passes in open butt joints and especially positional welding, in thinner materials. Close attention to operator technique is required to ensure adequate fusion when positional welding on thicker material. Fig 2 Globular transfer Upon increasing current above 200 amps but again depending on the wire size, there will be a transition to globular transfer where the short circuiting does not occur at a regular frequency. Fig 3. The wire tip will overheat and large globules of molten metal will form. Apart from wandering within the arc, the droplets will not always be directed into the weld pool and so create excessive spatter on impact with the parent material or weld pool. Therefore this type of transfer should be avoided for both solid and all types of cored wires. Fig 3 Spray transfer The spray transfer mode is established where a constant arc gap is maintained and the droplets which are extremely fine are projected across the arc gap in free flight. Fig 4. The weld appearance is enhanced and the greater heat input and arc force ensures excellent side wall fusion and penetration with a reduced incidence of defects. This mode is usually employed in situations where maximum deposition rates are possible and desirable. There are no restrictions regarding the use of any OK Tubrod cored wires with this method. Fig 4 80% Ar + 20% CO 2 100% CO 2 Flow rate It is important that flow rate at the torch is maintained within litres per minute for flux cored wires and litres per minute for metal cored wires. The rutile E70T-1 and E71T-1 types of cored wires will not operate satisfactorily in dip transfer and so are restricted to spray transfer. This is not a handicap since although two types of rutile wire may be required for flat and vertical to maximise deposition, the OK Tubrod 15.14/15.15 types (E71T-1) can operate in all positions using spray transfer but will not be as fast as the OK Tubrod (E70T-1) in the flat position. Except for possibly the overhead position solid wire is confined to dip transfer for positional welding which, in comparison, is slow and liable to give fusion defects unless operator technique is of a consistent high quality. The metal cored OK Tubrod 14.XX wires and OK Tubrod fully basic E71T-5 wires in 1.0mm to 1.4mm are capable of positional welding but only in the dip transfer mode. Pulsed arc transfer Pulsed arc welding is a controlled method of spray transfer which enables the transfer of droplets by projecting them across the arc gap at a regular frequency. The frequency can be varied at the power source to suit a particular application, type and size of wire. On more advanced equipment the pulse peak current and duration as well as background current can be adjusted. The action is illustrated in Fig 5 and shows a typical wave form together with a diagrammatic view of cyclic events at the wire tip. During the intervals between pulses a background current

22 maintains an arc to keep the wire tip molten but no metal is transferred. In this way transfer of metal occurs at high current but the mean total welding current remains low, thus the heat input and deposition are more easily controlled than with dip transfer. Fig 5 CURRENT (AMPS) MODULATED DC WAVE FORM TIME (M' SECS) There is no advantage to be gained by using rutile wires with pulsed MIG but it will allow larger sizes of metal cored types to be used at lower current levels than is the case with conventional equipment. The main benefits are to be found with solid wire and in particular stainless steel and aluminium. Synergic MIG welding This process is a sophisticated form of pulsed arc MIG welding where pulse parameters, static and dynamic characteristics are optimised for a given consumable on a pre-programmed basis. This provides for one knob parameter control with improved fusion characteristics and reduced spatter. Synergic pulsed welding with tubular wires is more complicated than with solid wires. The thermal and electrical conductivity of cored wires vary considerably due to differing wall thickness and filling formulations. Those factors lead to a higher peak current requirement for cored wires than for the equivalent size of solid wire. Therefore, not all pulsed power sources available can be used with cored wire although many will operate satisfactorily with metal cored wires due to the lower peak currents required. In addition, power sources have to be pre-set for each type of consumable to be used. Since in the case of cored wires, different manufacturer s products will vary in wall thickness and flux formulation and change of supplier, albeit for a wire of the same classification will not necessarily exhibit satisfactory running. 5 5 PULSE TIME CAN BE VARIABLE Although fully basic wires produce the highest integrity weld metal, it is unlikely that their running characteristics will match those of the EX1T-1 or OK Tubrod 15.14/15.15 type wires for positional welding within the foreseeable future. However, depending on the application, the use of synergic pulsed MIG can compensate for the lack of operability with an attendant reduction in spatter and superior fusion characteristics. Operating conditions Polarity DC electrode positive is recommended for the rutile flux cored OK Tubrod wires since the use of the negative pole produces inferior running characteristics and can occasionally produce porosity. With the exception of OK Tubrod 14.00, 14.05, and which will operate on both DC electrode positive and negative polarity, the other OK Tubrod metal cored and basic flux cored wires benefit from the use of the negative polarity giving improved arc action and weld finish with reduced spatter. Voltage Arc voltage has a direct influence on the arc length which controls the weld shape, depth of penetration and spatter level. As the arc voltage is reduced the penetration increases and this is particularly important in V butt joints. An increase in voltage will result in a long arc length and increase the risk of porosity and undercut. When operating on dip transfer for positional welding at comparatively low currents the arc voltage should be kept at the highest practicable level to ensure adequate side wall fusion. Amperage The welding current is directly related to the wire feed speed. The higher the feed speed then the higher the amperage drawn from the power source in order to melt the additional wire going into the weld pool. With flux cored wires the amperage used is ideally in the top half of the range specified for a particular size, except when positional welding with 1.0mm, 1.2mm and 1.4mm wires, and when the dip transfer mode is used at current below 220 amps. OK Tubrod metal cored wires eliminate the need for current variations relative to plate thickness since one current setting for a given wire size will cater for 90% of flat and HV applications. The weld crosssection is controlled by the travel speed whereas solid wire would require considerable current resetting to achieve the same flexibility. Plate preparation Due to superior side wall fusion obtained particularly from the metal cored wires the combined angles of preparations can generally be reduced. A V butt joint for instance that would normally need a 60 O included angle for manual arc welding can be reduced to 45 O thereby saving plate and hence weld metal to fill the joint. Fig 6 60 o 45 o 35 o 50 o The higher level of deoxidants and higher current density available with cored wires allows them to be used where mill scale and primer have to be tolerated. This is particularly so with the metal and basic cored wires, since the rutile types are the least tolerant. However, in the case of primer the degree of success will depend on the type and thickness, but generally OK Tubrod basic wires will achieve porosity free welds at speeds 45% faster than solid wires and the OK Tubrod metal cored wires are approximately 35% faster. Recent advances in the development of the all positional rutile OK Tubrod types have also given added security when welding on primed plate. For optimum radiographic standards with flux cored wires, excessive rust and scale should be removed by grinding which will also serve to reduce slag formation to a minimum when using metal cored wires. Further economies can be achieved from a reduction in weld metal required on single pass fillet joints. The often greater depth of fusion can increase the effective throat thickness and

23 consequently allow a reduction in leg length by up to 20%. The savings in weld metal are considerable as can be seen from Fig 7a and 7b and some certification authorities will permit a reduction of 50% in weld dimensions for single pass fillets when produced fully automatically. Torch angles and manipulation Torch angles and manipulation Vertical but welds Fig 7a Solid wire 10 O 10/20 O 1st pass Fill & Cap Fill & Cap Preparation of root face A torch angle of 10 O above the horizontal may be used for root passes to assist arc stability and penetration control. Preparation with feather edges Vertical fillet welds 6mm 8mm Fig 7b Cored wire Single pass 10 O 10/20 O Triangular weave for single pass fillets. If necessary subsequent weld runs should be deposited using techniques similar to that for filling vertical butt joints. No weaving is necessary for single pass fillets when using OK Tubrod 15.14/15.15 Restrict vertical down technique to thin plate or leg lengths of 6mm maximum. May be used for first pass or multipass joints. 6mm 6mm

24 Welding techniques Torch angles Flux cored wires With OK Tubrod flux cored wires the torch angle has a significant effect on slag control and weld deposit profile. For both fillet and butt joints the recommended angle between the wire axis and the line of joint is between 60 O - 70 O and using a backhand technique i.e; pulling, with the wire pointing towards the completed weld. In this way the arc force prevents the slag from running in front of the weld pool and reduces the risk of slag traps. For HV fillets the wire tip should be directed toward the bottom plate at approximately 3mm from the line of the joint with a torch angle of 45 O from the vertical plate. In certain circumstances the forehand technique i.e: pushing, can be used to advantage. On small fillet welds where penetration is not of paramount importance, the higher welding speeds required are such that the molten slag is prevented from running ahead of the weld pool. This also has the advantage of producing a mitre fillet where as the backhand method tends to produce a more convex profile. Metal cored wires Maximum penetration is obtained using a backhand (pulling) technique with a torch angle of 70/80 O between the wire axis and the joint line. This will also serve to optimise gas coverage and is particularly relevant to multi-pass butt welds. For fillet and lap welds, superior weld appearance is achieved using a torch angle of 60/70 O, and a forehand technique (pushing). This results in a more even distribution of weld metal, accompanied by a reduction in penetration. Travel speed Travel speed has an important influence on penetration. For example when using a 1.6mm metal cored wire at 350A an increase in travel speed from 30cm/min to 60cm/min approximately doubles penetration beyond the root of a fillet. At speeds in excess of 80/100 cm/min penetration will decrease. Similarly a reduction in penetration will occur if the welding speed should fall to below 30cm/min, as the arc can impinge on the molten pool in preference to the base material. In addition, the use of slow travel speeds should be avoided when low temperature impact properties are required. While the joint may be filled in fewer passes, the individual weld deposits will be of a large cross-section and therefore impact resistance will be Flux cored wires Flux cored wire Metal cored wires Metal cored wire 45 O O 70 O 90 O O 90 O 45 O O 45 O O

25 reduced. Apart from this, in the case of flux cored wires, there is the obvious difficulty of slag control to be considered. Positional welding The majority of the OK Tubrod cored wires are capable of positional welding in the smaller sizes. However, the choice of consumable must be given careful consideration in relation to the proposed application because the various ranges require quite different manipulation techniques for optimum results. Rutile types This type of wire allows the use of the spray transfer mode in all positions including overhead and as such affords very high deposition rates. In addition, the exceptional fusion characteristics that result will have significant effect on the production of defect free welds, Fig 8a. This is particularly relevant when compared to solid wire which by necessity can only be used for positional welding in the dip transfer mode. The reduced depth of fusion involved together with the greater degree of skill and concentration demanded will increase the risk of fusion related defects Fig 8b. In such circumstances the use of nonfusible backing is recommended and this type of wire is eminently suitable for use with these materials and the speed of welding will be significantly higher. Fig 10a and 10b. Metal cored and fully basic types These two groups may be treated as one with regard to positional welding techniques. To maintain optimum control welding is limited to the 1.0mm, 1.2mm and 1.4mm sizes and is restricted to the dip transfer mode where greater welder skill is involved. The manipulation required is similar to that used for solid wire in that initial passes in the vertical position are completed using a triangular weave motion. This is to ensure that the weld profile remains flat and not peaked, which would otherwise occur leading to possible lack of fusion defects at the edges after further welding as in the case of multi-pass joints. The conventional straight weave may be used but only in circumstances when the face of the previous pass is wide enough such that the effect of heat sink will maintain a flat profile automatically. Whilst the dip transfer method is slow and often demanding in terms of operator concentration, the arc energy is greater than with solid wire and the possibility of defects, especially cold lapping is substantially reduced. The root pass in an open butt weld, where full penetration is required from one side, is always the most difficult regardless of welding process or position. The choice will depend on the thickness of material and degree of root penetration desired. Multi-pass joints should be completed on a similar basis to that of butt welds using the vertical up technique. Fig 10a Front face Fig 10b Rear face Fig 8a Fig 8b OK Tubrod types can achieve in excess of 3 kg/hr in the vertical position compared to manual arc at 1 kg/hr max and solid wire at approximately 2 kg/hr. The techniques required for vertical up welding are almost identical to those employed with manual arc Fig 9, both for fillet and butt joints. However, root passes in open butt welds where a uniform bead of penetration is required when welded from one side are not recommended. This is due to the high arc energy and fluidity of the weld pool as well as the need to maintain highly accurate joint preparations which is not considered practical. Fig 9 However, when using Tubrod metal and basic cored wires the use of dip transfer and vertical down welding can be used to good advantage. Excellent results can be achieved more easily, it is rapid and plate preparation costs can be reduced by dispensing with a root face. Fillet joints may be welded using either the vertical up or vertical down techniques.

26 Electrode extension This term describes the distance between the contact tip of the torch and the work piece, sometimes described as electrode stickout. The current conditions should be set for the job in hand but during welding it may be necessary to reduce the amount of heat in the weld pool to accommodate poor fit-up or out of position welding. An increase in the stickout length and the extra electrical resistance that results will produce a cooler less fluid weld pool. Similarly any decrease in electrode extension will have the effect of increasing welding current and the characteristic can be of benefit in controlling penetration; especially where inconsistent fit-up is encountered. When operating with dip transfer an extension of 12mm will suffice for most applications, whereas spray transfer produces a greater amount of radiated heat and should have an extension of approximately 20-30mm. During actual welding any large variation will produce an inconsistent weld deposit and excessive electrode extension will reduce for effectiveness of the gas shield. For a given wire feed rate any lengthening of the extension has the effect of reducing the amperage drawn from the power source. Increasing the wire feed speed to compensate for the current drop will result in a significant increase in weld metal deposition. Fig 11. DIP TRANSFER Contact tip protrudes beyond the shroud 10-12mm Extension SPRAY TRANSFER IMPROVED ACCESS USING SHORT SHROUD SPRAY TRANSFER Contact tip within the shroud 25-30mm Extension Fig 11 Electrode extension related to deposition rate Extension mm Wire feed m/min Current Amps Dep rate kg/hr

27 Deposition data OK Tubrod 14.00/14.12 OK Tubrod mm 1.6mm 8 1.4mm 1.6mm mm 6 Kgs/Hr 5 1.2mm 6 Kgs/Hr Polarity DC- Electrode Extension 1.2mm 1.4mm 20mm 1.6mm Electrode Extension 1.2mm 1.4mm 20mm 1.6mm Amps Amps OK Tubrod OK Tubrod mm 5 1.2mm 1.4mm 1.6mm Kgs/Hr 2.4mm Kgs/Hr 1.2mm 2 Electrode Extension 1.2mm 1.4mm 20mm 1.6mm Amps 2 1 Electrode Extension 1.2mm = 20mm 1.6mm 2.4mm = 25mm Amps OK Tubrod OK Tubrod 14.3X 10 9 Tubrod 14.3X Stainless Cored Wires mm 8 1.6mm 7 1.2mm 7 6 Kgs/Hr 6 Kgs/Hr 5 1.2mm Electrode Extension 1.2mm = 20mm 1.6mm = 25mm Amps Amps

28 OK Tubrod estimating data Metal cored wire Tubrod 14.0X Series Fillet welds Dia T L Amps Wire feed Volts Welding Arc time Wire weight Gas mm mm mm speed speed min/m kgs/m litres/m cm/min cm/min Butt welds 60 O Wire Weldfeed ing Arc Wire Dia. T Run speed speed time weight Gas mm mm No. Amps cm/min Volts cm/min min.m kgs/m litres/m T mm Root gap T 1.5mm Root face mm Root gap T T T O O O O Vertical O Overhead A B C 3.0mm gap 2.5mm 2.4mm A A A B C VERTICAL V/D V/U V/U V/U V/D V/U V/U V/U V/D V/U V/U V/U V/U OVERHEAD NOTES 1. Shielding gas flow rate litres/min. 2. Contact tip to work distance 25-30mm. 3. Pull the torch with an angle of 70 o to the line of the joint.

29 Flux cored wire Tubrod 15.XX Series L T OK Tubrod and 1.6mm fillet welds HV position Wire feed Welding Arc Wire Gas Dia T L Current speed Volts speed time weight litres/m mm mm mm amps cm/min cm/min min/m kgs/m L T OK Tubrod and 2.4mm fillet welds - downhand position Wire feed Welding Arc Wire Gas Dia T L Current speed Volts speed time weight litres/m mm mm mm amps cm/min cm/min min/m kgs/m OK Tubrod mm vertical up butt weld Wire Plate Run Amps feed Volts Welding Arc Wire Gas thickness No. speed speed time weight litres/m mm cm/min cm/min min/m kgs/m V/D V/U V/U V/U V/U 1.5mm 4/5mm 50 O 20mm OK Tubrod mm downhand butt weld Wire Plate Run Amps feed Volts Welding Arc Wire Gas thickness No. speed speed time weight litres/m mm cm/min cm/min min/m kgs/m / mm 60 O 2mm 45 O 45 O 1.5mm 1.5mm OK Tubrod mm downhand butt weld Wire Plate Run Amps feed Volts Welding Arc Wire Gas thickness No. speed speed time weight litres/m mm cm/min cm/min min/m kgs/m mm

30 OK Tubrod mm fillet welds - HV position Wire feed Welding Arc Wire Gas Dia T L Current speed Volts speed time weight litres/m mm mm mm amps cm/min cm/min min/m kgs/m For larger sizes refer to OK Tubrod below L T OK Tubrod fillet welds - HV position Wire feed Welding Arc Wire Gas Dia T L Current speed Volts speed time weight litres/m mm mm mm amps cm/min cm/min min/m kgs/m mm 50 O 3.0mm OK Tubrod mm downhand butt weld Wire Plate Run Amps feed Volts Welding Arc Wire Gas thickness No. speed speed time weight litres/m mm cm/min cm/min min/m kgs/m L T OK Tubrod 15.14/15.15 fillet welds Wire feed Welding Arc Wire Gas Dia T L Current speed Volts speed time weight litres/m mm mm mm amps cm/min cm/min min/m kgs/m Horizontal vertical Vertical up Vertical down /3mm 4.0mm 50 O 20mm OK Tubrod 15.14/ mm vertical up butt weld Wire Plate Run Amps feed Volts Welding Arc Wire Gas thickness No. speed speed time weight litres/m mm cm/min cm/min min/m kgs/m

31 OK Tubrod 15.14/ mm downhand butt weld Wire Plate Run Amps feed Volts Welding Arc Wire Gas thickness No. speed speed time weight litres/m mm cm/min cm/min min/m kgs/m mm 50 O 3.0mm 2.0mm 45 O 15 O OK Tubrod 15.14/ mm horizontal vertical butt weld Wire Plate Run Amps feed Volts Welding Arc Wire Gas thickness No. speed speed time weight litres/m mm cm/min cm/min min/m kgs/m mm 20mm 50 O OK Tubrod 15.14/ mm downhand butt weld Wire Plate Run Amps feed Volts Welding Arc Wire Gas thickness No. speed speed time weight litres/m mm cm/min cm/min min/m kgs/m /3mm 4mm 25mm 1.5mm OK Tubrod 15.14/ mm vertical up butt weld Wire Plate Run Amps feed Volts Welding Arc Wire Gas thickness No. speed speed time weight litres/m mm cm/min cm/min min/m kgs/m O

32 Mechanical properties For a variety of reasons fabricators are required to attain progressively higher charpy V notch properties from welded joints using C/Mn weld metal at low temperatures, typically -30 O C. The welding consumables have a significant role to play in producing high purity weld metal with controlled S and P levels but unless strict control of heat input and welding procedure are observed the desired results will not be achieved. The heat affected zone (HAZ) hardness will also have an effect although problems in this area cannot be attributed to the welding consumable. High HAZ hardnesses obviously reduce ductility, but under the influence of hydrogen which can be produced via the consumable, premature failure can result. Heat input This is expressed as kilojoules per mm (kj/mm) and is useful for predicting the welding parameters that may be required. The formula used to establish the heat input value is: HI(kJ/mm) = Arc Voltage x Amperage x 60 Welding Speed mm/min x 1000 In the case of C/Mn weld metal the heat input levels that can be relied upon to give good results with cored wires are between kj/mm. From this, therefore, the size of wire can be roughly determined together with the electrical parameters and travel speed that must be maintained. It can be seen in Fig 13 that -30 O C is the normal transition zone for C/Mn weld metal and also the effect of heat input in moving this transition to a more favourable position. The use of excessive heat input through the use of high amperage and slow travel speeds will produce large weld deposits that will certainly fill the joint rapidly. However, the welds will exhibit a very coarse dendritic structure characterised by low ductility and hence poor low temperature toughness. The heat affected zone The hardness of the heat affected zone, which is in the plate adjacent to the fusion zone, is not directly attributed to the consumable, but the welding activity will have an effect on the inter - pass temperature and therefore hardness. Welding is used to make joints and so cannot be viewed in isolation, therefore, it is necessary to be mindful of the effects of welding on the total joint. It may be that welding is taking place within the laid down procedure relating to run sequence and heat input (kj/mm) but the plate thickness and joint length can be such that, although a preheat may have been employed, heat is being taken away at a faster rate than it is being replaced by the welding. This cooling will lead to undesirable hardening of the heat affected zone so that although the weld metal toughness is good the HAZ will be comparatively brittle. In these cases it may be possible to review the welding parameters or as is generally the case continuous external heating will have to be incorporated. Conversely, if the heat input from welding causes a progressive increase in the interpass temperature, welding will have to stop periodically to maintain it within the defined limits. Most high yield C/Mn steels above 25mm thick will require a preheat of 150 O C with a maximum interpass temperature of 250 O C to ensure satisfactory results. Preheat levels can often be lower with cored wires since they are used at a higher heat input then solid wire or manual metallic arc. Hydrogen It is not proposed to make an in-depth study on the effect of hydrogen in the HAZ as it is already well documented, but comment is needed in relation to cored wires. Basic manual arc electrode coatings can be prone to moisture absorption often necessitating redrying before use. Advances in coating formulations have, however, dramatically improved their tolerance (i.e. Esab VacPac). Rutile electrodes cannot be used for high integrity welding since by nature they contain water bearing agents which are essential to their satisfactory running. Cored wires are not so susceptible as the core is completely enclosed which eliminates the need for re-drying before use. OK Tubrod fully basic wires will produce less than 5ml of diffusible hydrogen per 100g of weld metal and usually less than 3ml straight from the box and OK Tubrod metal cored wires will also produce typically less than 5ml. With the development of rutile based cored wires, use can be made of their attractive operability yet still maintain acceptable hydrogen levels which is not the case with their manual arc equivalents. However, the level of hydrogen produced is related to size of wire and current used. Fig mm up to 200A <5mls/100g 1.2mm A 5-7mls/100g 1.6mm A <10mls/100g Fig 12 Low alloy wires For test temperatures below -30 O C (-40 O C) it is necessary to revert to low alloy wires, usually Ni bearing for toughness and Mo for tensile strength or a combination of both. Typically the 2.5% Ni types will move the transition point to below -60 O C for the more severe applications. However, in the case of C/Mn steels for test temperatures at -40 O C and provided Ni is permissible, use can be made of Tubrod This wire contains 1% Ni and is rutile based, but if weld metal from rutile based wires have a higher oxygen level than that of fully basic types, this deficiency is certainly compensated for by the Ni. For temperatures in the region of -20 O C increases in productivity can also be achieved by increases in heat input and deposition rate. In this case the drop in toughness that would otherwise occur with C/Mn weld metal will be offset by the 1% Ni. Welding procedure In any welding procedure where low temperature toughness is required, the run sequence will decide the degree of structure refinement produced without necessarily adversely affecting productivity. Large welds and wide weaving should be avoided so the use of a split weave technique must be adopted as soon as practicable after completing the root. Fig 14a. This will ensure maximum grain refinement. Whilst the weld pass sequence in Fig 14b is described as unsatisfactory it may be used if unavoidable, but each layer using the broad weave technique must be as thin as possible. When welding in the vertical position, welding speed is slow and there is a tendency to produce larger weld deposits with attendant higher heat input than in other positions. It is particularly important to restrict their size Fig 14c since the charpy values achieved in the vertical position will generally be lower than the flat or horizontal vertical position Fig 15.

33 Typical transition curves Butt joint Low Heat Input 60 JOULE C/Mn + 2% Ni C/Mn High Heat Input Fig 13 TEMP O C Fig 14a Satisfactory Fig 14b Unsatisfactory Fig 14c Satisfactory Welding Preparation Wire No A V Mechanical properties position and pass dia Charpy V Bend test 120 O radius sequence mm J/ +0 _ O C J/-20 O C face root Flat (IG) ,105 75,67 OK OK ,105 71,71 Vertical up ,76 39,43 OK OK 1 (3G) ,74 39,39 Fig 15

34 Welding procedure data OK Tubrod O OK Tubrod mm Material: NQ-1 Thickness: 25mm Size Run Amps Volts mm No / Position: ASME 1X-1G 1 Transverse tensile test 808 N/mm 2 Fractured in plate Test Temp Centre line -20 O C O C Transverse tensile test 808 N/mm 2 Fractured in plate OK Tubrod Material: OX812E Thickness: 16mm Position: ASME 1X-1G 60 O Size Run Amps Volts Heat input mm No kj/mm Transverse tensile test 810 N/mm 2 Centre line Test Temp Centre line -20 O C O C OK Tubrod Material: OX 812E Thickness: 20mm Position: ASME 1X-1G 60 O Size Run Amps Volts Heat input mm No kj/mm Test Temp Centre line 0 O C O C O C O C

35 50 O OK Tubrod Material: NAXTRA 70 Thickness: 25mm Position: ASME 1X-1G Size Run Amps Volts No mm Transverse tensile 803 N/mm 2 Test Temp Cap -2mm -20 O C O C OK Tubrod OK Tubrod Material: BS E Thickness: 45mm Position: ASME 1X-3G Size Run Amps Volts Heat input mm No kj/mm / /3.0 CTOD performance (BS 5762) -10OC mm 45 O OK Tubrod Material: OX506 Thickness: 13mm Position: ASME 1X-2G Size Run Amps Volts mm No / / Test Temp Centre line -54 O C *Non-fusible backing O

36 1 2 3 OK Tubrod Material: USITEN 355N2 Thickness: 16mm Position: ASME 1X-3G 4 50 O Size Run Amps Volts mm No / Test Temp Centre line -54 O C OK Tubrod Material: EH2 Thickness: 30mm Position: ASME 1X-3G Size Run Amps Volts mm No O Test Temp Centre line -20 O C O C O C

37 OK Tubrod OK Tubrod Material: BS4360: 50E Thickness: 25mm Position: ASME 1X-1G Heat treatment: Stress relief 600 O C 1 1 /2 hrs Size Run Amps Volts mm No Solid Wire: Autrod mm Transverse tensile: UTS 579N/mm 2 fracture in plate Test Temp Weld Root -40 O C OK Tubrod mm Material: BS4360: 50D Thickness: 63mm Position: ASME 1X-1G Heat treatment: Stress relief 625 O C: 2 1 /2 hrs. Size Run Amps Volts Heat input mm No kj/mm MMA / Back groove 1 MMA / Test Temp Centre Line -10 O C O C O C CTOD performance (BS 5762) -10 O C mm OK Tubrod Material: BS4360: 50E Thickness: 25mm Position: ASME 1X-1G Heat treatment: Stress relief 600 O C 1 1 /2 hrs Run Size Amps Volts No mm Transverse tensile: UTS 562 N/mm 2 fracture in plate. 6mm Test Temp Centre line -20 O C

38 OK Tubrod mm Material: BS4360: 50D Thickness: 50mm Position: ASME 1X-1G Pre-heat: 100 O C lnterpass: 250 O C Size Run Amps Volts Heat input mm No kj/mm Longitudinal tensile test TS 595 N/mm 2 YS 529 N/mm 2 Test Temp Cap Root -30 O C O C O C O C CTOD performance BS OC mm OK Tubrod mm Material: BS4360 Thickness: 50mm Size Run Amps Volts Heat input mm No kj/mm Test Temp Weld Root -20 O C Position: ASME 1X-3G

39 OK Tubrod OK Tubrod mm Material: API: 5L X60 Thickness: 28mm Position: ASME 1X-6G Size Run Amps Volts Heat input mm No kj/mm Test Temp Centre line -40 O C OK Tubrod mm Material: RAEX 385 Thickness: 16mm Position: ASME IX-2G Size Run Amps Volts mm No Test Temp Centre line -20 O C O C O C OK Tubrod mm Material: RAEX 385 Thickness: 16mm Position: ASME IX-4G Size Run Amps Volts mm No Test Temp Centre line -20 O C O C O C

40 OK Tubrod mm Material: BS4360: 50D Thickness: 40mm Position: ASME 1X-2G Preheat: 100 O C lnterpass: 250 O C max Size Run Amps Volts Heat input mm No kj/mm /250 24/ / Test Temp Cap Root Root (back gouged) -30 O C O C O C OK Tubrod mm Material: BS4360: 50D Thickness: 50mm Position: ASME 1X-3G Preheat: 100 O C lnterpass: 250 O C max. Size Run Amps Volts Weld Heat mm No Speed Input mm/min kj/mm Back groove weld 2nd side Test Temp Cap Root -30 O C O C O C CTOD performance (BS 5762) - 10 O C mm OK Tubrod mm Material: BS4360: 50D Thickness: 40mm Position: ASME 1X: 3G Preheat: 100 O C lnterpass: 250 O C max Size Run Amps Volts Heat input mm No kj/mm / / Test Temp Cap Root Root (back gouged) -30 O C O C O C

41 OK Tubrod mm Material: BS4360: 50D Thickness: 50mm Position: ASME 1X-3G Preheat: 75 O C lnterpass Temp: 250 O C Max Size Run Amps Volts Heat input mm No kj/mm Back Grind Test Temp Cap 1 Cap 2 Root -40 O C (73) (86) (54) CTOD performance (BS5762) - 10 O C mm OK Tubrod OK Tubrod mm 0-1mm mm 12mm Material: CE:0.35% Thickness: 12mm Size Run Amps Volts Heat input mm No kj/mm Test Temp Weld -55 O C Position: ASME 1X-3G Pre-heat: 20 O C Interpass: 250 O C OK Tubrod mm Position: ASME 1X-3G Material: BS4360: 50D Pre-heat: 120 O C Thickness: 50mm Interpass: 180 O C Size Run Amps Volts Heat input mm No kj/mm Test Temp Cap -40 O C O C CTOD performance (BS 5762) -10 O C mm

42 OK Tubrod mm Material: BS4360: 50D Thickness: 20mm Position: ASME 1X-3G Pre-heat: None Interpass: 250 O C Size Run Amps Volts Heat input mm No kj/mm Longitudinal tensile test: TS 602 N/mm 2 YS 540 N/mm 2 Test Temp Cap Centre Line Root -40 O C O C OK Tubrod OK Tubrod mm Material: BS 4360: 50D Thickness: 63mm Position: ASME 1X-1G Size Run Amps Volts Heat input mm No kj/mm Side Side Stress relief 625 O C - 2.5HRS Test Temp Centre line -10 O C O C O C O C O C CTOD performance (BS5762) -10 O C mm OK Tubrod Side 1 Side 2 Material: BS4360: 50D Thickness: 63mm Size Run Amps Volts Heat input mm No kj/mm / / / Back groove / / / / CTOD performance (BS 5762) -10 O C mm Position: ASME 1X-1G Heat treatment: As welded

43 OK Tubrod OK Tubrod mm Material: BS4360: 55F Thickness: 50mm Position: ASME 1X-2G Pre-heat: 100 O C Interpass: 200 O C Size Run Amps Volts Heat input mm No kj/mm 1-3 MMA (E8016-G) Longitudinal tensile UTS 638 N/mm 2 YS 581 N/mm 2 Test Temp Cap Root -40 O C O C CTOD performance (BS 5762) -10 O C mm OK Tubrod mm Material: BS4360: 50D Thickness:50mm Size Run Amps Volts Heat input mm No kj/min Back groove Longitudinal tensile UTS 592 N/mm 2 YS 516 N/mm 2 Position: ASME 1X-2G Pre-heat: 100 O C Interpass: 250 O C Heat treatment: Stress relief, 600 O C 4 hrs Test Temp Cap Root -40 O C O C CTOD performance (BS 5762) -10 O C mm OK Tubrod OK Tubrod mm Material: HY80 Thickness: 30mm Position: ASME 1X-1G Pre-heat: 120 O C min Interpass: 150 O C max Size Run Amps Volts Heat input mm No kj/mm MMA (E9016-G) Longitudinal tensile: UTS 696 N/mm 2 YS 651 N/mm 2 Test Temp Cap -40 O C O C O C

44 OK Tubrod mm Material: HY80 Thickness: 30mm Position: ASME 1X-2G Pre-heat: 120 O C min Interpass: 150 O C max Size Run Amps Volts Heat input mm No kj/mm MMA (E9016 G) /9 1.4 Longitudinal tensile: UTS 675 N/mm 2 YS 619 N/mm 2 Test Temp Cap -40 O C O C O C OK Tubrod mm Material: Q1 (N) Thickness: 55mm Position: ASME 1X-2G Pre-heat: 120 O C Interpass: 150 O C Size Run Amps Volts Heat input mm No kj/mm MMA (E9016-G) /310 23/ Back groove /310 23/ All weld tensile: Side 1 UTS 735 N/mm 2 YS 683 N/mm 2 Side 2 UTS 756 N/mm 2 YS 710 N/mm 2 Test Temp Weld - Side 1 Weld - Side 2-50 O C OK Tubrod mm Material: HY80 Thickness: 30mm Position: ASME 1X-1G Pre-heat: 120 O C min Interpass: 150 O C max Size Run Amps Volts Heat input mm No kj/mm MMA (E9016-G) Longitudinal tensile: UTS 619 N/mm 2 YS 553 N/mm 2 Test Temp Cap -40 O C O C O C

45 OK Tubrod mm Material: Q2 (N) Thickness: 50mm Position: ASME 1X-2G Pre-heat: 120 O C min Interpass: 150 O C max Size Run Amps Volts Heat input mm No kj/mm Back Groove Longitudinal tensile Side 1 UTS 814 N/mm 2 YS 763 N/mm 2 Side 2 UTS 785 N/mm 2 YS 737 N/mm 2 Test Temp Side 1 Side 2-50 O C OK Tubrod mm Material: Q2 (N) Thickness: 50mm Position: ASME 1X- 1G Pre-heat: 120 O C Interpass: 150 O C max Size Run Amps Volts Heat input mm No kj/mm Back grind Longitudinal tensile: Side 1 UTS 737 N/mm 2 YS 702 N/mm 2 Side 2 UTS 757 N/mm 2 YS 700 N/mm 2 Test Temp Weld Side 1 Weld Side 2-40 O C O C O C

46 15 OK Tubrod mm OK Tubrod mm OK Tubrod mm Material: E32/A1S1 316 Position: ASME 1X-3G Clad Steel Pre-heat: - Thickness: 47mm Interpass: 150 O C max Size Run Amps Volts Heat input mm No kj/mm Side 1: OK Tubrod Side 2: OK Tubrod OK Tubrod OK Tubrod Transverse tensile: Fracture in plate Test Temp Side 1 (Cap - 2mm) Side 2 (Cap - 2mm incl S/S) -60 O C Bend Test Stainless + C/Mn C/Mn >120 O OK >120 O OK OK Tubrod OK Tigrod mm 2.4 mm Material: Duplex Grd S31803 pipe Thickness: 46mm-610mm O.D Position: ASME 1X-2G Pre-heat: 25 O C Interpass: 150 O C max Size Run Amps Volts Heat input mm No kj/mm GTAW FCAW Transverse tensile: 735 N/mm 2. Fracture in plate. Test Temp Weld Fusion LineRoot Fusion Line -30 O C O C Bend Test Side bends x 4 >120 O OK

47 Welding of stainless steel Types of stainless steel If chromium is added to carbon steel in amounts exceeding 12% it imparts corrosion and heat resistance and, as such, is the most important alloying element in stainless steel. The presence of chromium causes a film of chromium oxide to be formed on the surface of the steel which affords protection in corrosive environments. However, in less oxidising conditions such as those experienced during exposure to certain acids, insufficient oxygen is present for the protective film to form. Additions of 8-10% nickel will improve corrosion resistance in such circumstances and higher levels up to 15% will serve to maintain strength at elevated temperatures. Frequently molybdenum and smaller amounts of other elements are added to improve further corrosion and/or strength under specific conditions. The variety of stainless steels is enormous but, to simplify the situation, they can be categorised broadly into three main types: Martensitic 13% - 16% Cr These contain from 12% to a maximum of 16% chromium as the main alloying element, with carbon 0.3% maximum. In certain special applications the carbon in this class of steel may exceed 0.3%. These materials are capable of being hardened, consequently their welding presents difficulties unless special precautions are taken. Steels of this type are used for cutlery, spindles, shafts and applications requiring good resistance to corrosion and scaling at elevated temperatures up to approximately 800 O C. These steels harden when welded, so to reduce the hardness in the heat affected zone and avoid the danger of cracking, it is necessary to preheat to O C followed by slow cooling after welding. This should be followed, if possible, by a post-heat at O C. For ductile joints free from cracks, an austenitic stainless steel consumable is normally used. Weld metal or similar composition is usually employed for limited applications such as overlaying and minor attachments, etc. Ferritic 16% - 30% Cr Used where very high temperature scaling resistance is required. For example; furnace parts, oil burners, etc. Materials of this group are not hardened by heat-treatment, but are liable to brittleness caused by excessive grain growth at high temperatures above 115 O C. This results in a weld which is brittle at ordinary temperatures, though it may be quite tough at red heat at which it operates in service. Steels of this type do not harden when welded. Preheating to 200 O C is recommended to ensure safe handling while a post-heat treatment at 750 O C helps restore ductility by recrystallisation of the weld. For mildly corrosive applications and where the presence of nickel-bearing weld metal can be tolerated (these steels are frequently used in sulphurbearing atmospheres which attack nickel) an austenitic stainless steel wire is recommended. A weld of this type also provides a joint capable of deformation in further processing operations. Austenitic 19% Cr 9% Ni (+ Mo) The austenitic group represents the largest and most important range used in modern industry and contain a minimum of 18% Cr and 8% Ni. Their austenitic structure ensures that they are soft and ductile with excellent weldability. Welding techniques The welding techniques required for austenitic stainless steel are in many respects similar to those used for mild steels, except that various precautions are essential particularly with regard to distortion. Factors to be considered are: Poor heat conductivity - 1 /3 that of mild steel. Heat is not dissipated from the weld area so rapidly as with mild steel. High coefficient of expansion /2 times that of mild steel. Shrinkage stresses are increased and hence the risk of distortion. Table 1 Welding procedures Higher specific resistance - 5 times that of mild steel. Stainless steel can attain red heat more rapidly, therefore lower currents should be used to avoid overheating of the base material. Where possible a consumable that matches the composition of the base material should be used. However, fully austenitic weld metal is sensitive to hot cracking, so the weld metal will ideally contain 5-9% ferrite to prevent this. Duplex stainless steels The use of Duplex stainless steels is rapidly increasing in preference to the standard fully austenitic steels previously described. In comparison to, for example, a 316L material which will contain 5-9% ferrite, the Duplex steels contain 50% ferrite and 50% austenite, hence the term Duplex. The resulting micro structure produces the following advantages: Superior resistance to pitting corrosion. Higher tensile strengths permit the use of thinner sections and consequently reduce overall weight. Lower risk of stress corrosion cracking. Comparable weldability to the standard fully austenitic steels. Excellent mechanical properties in the temperature range -50 O C to 280 O C. Weld Process Consumables Dia. Weld Plate Heat Ferrite Charpy V Metal mm position thickness Input FN(AV) +20 C(J) A MMA OK /3.0 1G 9 mm B MMA OK G 13 mm C SAW OK G 13 mm D FCAW OK G 9 mm E FCAW OK G 13 mm OK Autrod was used with OK Flux OK Tubrod was used with CO 2 Shielding Gas.

48 Weldability The essential requirement during the fabrication and welding of Duplex steels is to maintain the balance of ferrite and austenite within the micro-structure to optimise service performance. This can be affected by: Dilution - Influenced by size of consumable relative to joint geometry and current used, which in turn affects weld metal composition. Heat Input It should be maintained between 0.5 and 2.5 kj/mm of weld deposit. Interpass Temperature - Indicating the maximum temperature between passes, it should not exceed 150 O C. Working Temperature - The material generally should not exceed 300 O C. Failure to observe these basic rules results in the formation of brittle phases, a reduction in corrosion resistance or mechanical properties or a combination of all three. It is the ferrite content that provides the strength and austenite the corrosion resistance and it is therefore vital that the balance between the two structures be maintained so far as possible. Dilution has a most marked effect which in turn can be exaggerated by an additional heat input. Manual metal arc will give the least dilution with minimal weld metal Ni loss and will consequently maintain austenite limits. The submerged arc process will lead to an increase in ferrite content and consequently a reduction in the austenite because of its comparatively higher dilution. It has been noted, however, that the submerged arc process does produce weld metal of excellent notch toughness, especially at room temperature, although this is believed to be attributed to the low O 2 content over-riding the effect of the increased ferrite. The precautions indicated may give the impression that the successful welding of Duplex steels is complex with a high risk of compromising the physical properties. This, in fact is not so, as good welding practice with any of the popular welding processes will ensure a heat input within the stipulated range of kj/mm. In selecting a suitable welding process productivity will be an obvious consideration so, if there are any doubts about projected heat input, it can be evaluated by reference to the formula on page 32. Of all the suitable processes when viewed in terms of flexibility, productivity, weld metal composition and mechanical properties, flux cored wires such as OK Tubrod and produce the most beneficial compromise. (Table 1). Super duplex stainless steels The most important elements in duplex steels are Cr, Ni, Mo and N and most super duplex types contain additions of Cu and W. It is the Cr Mo and N that impart the corrosion resistance and in particular resistance to pitting and crevice corrosion in chloride enriched environments. Duplex steels are classified according to their pitting corrosion resistance by a PRE N number calculated from the formula %Cr x %Mo + 16 x %Ni. The standard duplex steels will have a PRE N rating of between 25 and 38 whereas super duplex steels will exceed 40 - see Table 2. The higher value with super duplex steels is due to the higher alloy and N content and the much improved properties have extended their use considerably. Table 2 Examples of common duplex stainless steel grades Steel grade Classification Chemical composition (wt.%)* (Old UNS/New Cr Ni Mo N Cu W PRE N ** UNS/W.Nr) a) 23% Cr - Mo-free duplex stainless steels (=25) SAF2304 S / S / UR 35 N b) 22% Cr - Standard duplex stainless steels (30-36) SAF2205 UR 45 N S / S / AF c) 25% Cr - (0-2.5% Cu) Duplex stainless steels (32-40) Ferralium 255 S / S DP 3 S / S d) 25% Cr - Super duplex stainless steels (>40) SAF2507 S / S UR 52 N+ S / S Zeron 100 S / s

49 Consumables OK Tubrod rutile cored wire is recommended for the welding of super duplex steels and has a similar composition. The Ni content always over matches the base materials, as is also the case with OK Tubrod 14.27/37 to promote austenite during cooling. Table 3. Matching consumables or welding without filler (high dilution) will promote excessive ferrite and possibly embrittlement so this should be avoided unless post weld solution annealing is to be carried out. Wires over alloyed in Ni should, therefore, always be used on welded fabrications for service in the aswelded condition. Although corrosion resistance of duplex weld metals is generally more than adequate, it will normally be lower than that of unaffected base material. It will depend on the phase balance of ferrite and austenite which is affected by cyclic heating during welding, cooling rate and so on. The higher alloyed 25% Cr super duplex steels are especially sensitive and so heat input has to be controlled within closer limits if the higher corrosion resistance is to be maintained and embrittlement avoided. A range of kj/mm is advisable and the inter-pass temperature controlled within the range 100 O C-150 O C. If optimum mechanical properties are required the interpass temperature should be 100 O C max. Table 4. To improve corrosion resistance of weld deposits in standard 22% Cr duplex steels it is becoming increasingly popular to use super duplex consumables such as OK Tubrod which is quite acceptable. Shielding gas It is vital to maintain N levels if corrosion resistance is to be preserved. The shielding gas does have an affect on N content of the weld metal and, for example, in TIG welding N is frequently added from 1-3% to make up for losses and improve corrosion resistance. This is especially relevant in root areas where dilution will be high. With regard to flux cored wires, the rutile OK Tubrod types are recommended for use with Ar+20-25% CO 2. Welding of clad steel The use of a clad-material, consisting of a mild or low-alloy steel backing faced with stainless steel, combines the mechanical properties of an economic backing material with the corrosion resistance of the more expensive stainless facing. This facing usually consists of austenitic stainless steel of the 18/8 or 18/10 type, with or without additions of molybdenum, titanium and niobium, or a martensitic stainless steel of the 13% chromium type. The stainless steel cladding is normally 10 to 20% of total thickness. The welding material which is clad or lined with 13% Cr (martensitic) steels usually requires a preheat of 250 C and the use of an austenitic wire of appropriate type. Welding should be followed by a postheat treatment, though satisfactory results can be obtained without these precautions if, during welding, heat dissipation is kept to a minimum. This will help to temper the heat-affected zone by utilising the heat build-up from adjacent weld runs. The carbon steel backing should be welded first making sure that the carbon steel weld metal does not come into contact with the stainless cladding. This Closed Butt with Root Face Table 3 Typical chemical composition of all weld metals (wt%) Wire C Si Mn Cr Ni Mo N PRE N OK Tubrod 14.27/Ar + CO OK Tubrod 14.28/Ar + CO Table 4 Recommended heat input and interpass temperature for welding duplex and super duplex stainless steels Type Recommended heat Maximum interpass input* (kj/mm) temperature ( C) 23% Cr Mo-free duplex % Cr Standard duplex % Cr (0-2.5% Cu) duplex ** 25% Cr Super duplex ** * The heat input should be selected relative to the material thickness. ** A maximum interpass temperature of 100 C is recommended for optimum weld properties. Open Butt can be achieved in two ways, either by cutting the cladding away from both sides of the root, or welding with a close butt preparation and a sufficiently large root-face. The joint is then back grooved from the clad side to a sufficient depth to allow the deposition of a high alloy type weld metal, e.g: 309, to compensate for the dilution effect from the two dissimilar steels. Failure to do so will not only result in the depletion of alloy it could also render the clad side weld brittle. It is necessary to weld the cladding with a wire of matching composition to ensure continuity of corrosion resistance and physical requirements. For practical purposes it may be desirable to weld the joint totally from the clad side. In such circumstances

50 Complete welding from clad side Double V joint HV fillet joint welding of the joint should proceed in the normal manner until the carbon steel weld metal is one layer short of the cladding. The high alloy 309 weld metal should be employed for the area of interface with the cladding followed by capping of the joint with a consumable that matches the clad composition. Welding of dissimilar steels Situations frequently arise when it becomes necessary to weld an austenitic stainless steel to a mild or low alloy ferritic steel. In selecting a suitable electrode, the effect of dilution of the weld metal by the base material must be considered. The weld metal may be diluted from 20-50% depending on the welding technique used. Root runs in butt joints are the most greatly affected since all subsequent runs are only in partial contact with the base material and share dilution with neighbouring runs. If a mild or low alloy steel wire is used to weld stainless to mild steel, the pick-up of chromium and nickel from the stainless steel side of the joint could enrich the weld metal by up to 5% chromium and 4% nickel. This would result in a hardened crack sensitive weld. Austenitic stainless steel electrodes are, therefore, used for joining dissimilar metal combinations of stainless materials to mild and low alloy ferritic steels. However the correct type, which has sufficient alloying to overcome the effects of dilution from the mild or low alloy steel side of the joint, must be selected since if the weld metal does not start with an adequate alloy content the final weld may contain less than 17% chromium and 7% nickel. Weld metal with lower chromium and nickel contents are crack sensitive. Also if as a result of dilution the weld metal is incorrectly balanced with nickel and chromium, there may not be sufficient ferrite present in the weld metal to prevent fissuring and subsequent cracking taking place. For these reasons an austenitic stainless steel wire of the 20/9/3, 25/12 or 19/8/6 should be used. Their composition has been specially balanced to ensure that the total alloy content is adequate to accommodate dilution effects and which have a ferrite content sufficient to provide high resistance to hot cracking. Schaeffler diagram A useful method of assessing the general metallurgical characteristics of any stainless steel weld metal is by means of Schaeffler s diagram. The various alloying elements are expressed in terms of nickel or chromium equivalents, i.e. elements which like nickel tend to form austenite and elements like chromium which tend to form ferrite. By plotting the total values for the nickel and chromium equivalents on the Schaeffler diagram a point can be found indicating the main phases present in the stainless steel and this provides certain information as to its behaviour during welding. The diagram indicates that the comparatively low alloyed steels are hardenable since they contain the martensitic phase in the as-welded state. As the alloying elements increase, the austenite and ferrite phases become more stable and the alloy ceases to be quench hardenable. Steels with a relatively high level of carbon, nickel and manganese become fully austenitic ( Austenite area) while those with more chromium, molybdenum etc. tend to be fully ferritic ( Ferrite areas). There is also an important intermediate region of duplex compositions indicated as A + F on the diagram. In this region the welds contain both austenite and ferrite. This leads to the general classification of stainless steels into austenitic, ferritic, and martensitic, according to which phase is predominant. It is especially useful to determine the structure and hence physical characteristics of weld deposits when joining dissimilar steels by plotting the effects of dilution. The actual degree of dilution will depend on the application, plate preparation and thickness as well as the welding parameters used, but the following example will highlight some of the potential problems. Example: Imagine that a high quality C/Mn structural steel is required to be welded to an AISI 308 stainless steel. Experience has shown that a high alloy weld metal with ferrite should be adopted for this application but frequently 316L weld metal is used and this exercise will examine the dangers. Having calculated the Ni and Cr equivalents of the two steels they are plotted on the diagram and a line drawn from the C/Mn steel at point (A) to the 308 at point (B). It is assumed that equal amount of the base material will dilute the weld metal so a point is marked midway along the line (A), (B) and indicated by (C).

51 The Ni and Cr equivalents of the proposed weld metals, in this case 316L (OK Tubrod 14.31) and 309L (OK Tubrod 14.32), are now calculated and plotted on the diagram. A line is drawn from each weld metal equivalent to the midway point (C) on line (A), (B). The weld metals will also be diluted by approximately 30% so a point is marked 30% back from the weld metal plots toward the 50% steel dilution mark (C) and denoted (1) and (2). These indicate the structural condition of the weld metal from which a choice will be made. Steels Type Equivalents AISI 308 Ni 11.6% - Cr 19.0% BS D Ni 5.2% - Cr 0.45% Weld Metals Type Equivalents 316L Ni 14.62% - Cr 23.1% 309L Ni 15.25% - Cr 26.0% Assessment 1. The C/Mn structural steel to 308 stainless steel using 316L weld metal. The final composition of the weld is indicated by plot (1) which shows that it will be totally austenitic. This structure has a tendency toward hot cracking. In addition, if dilution is increased by up to 45%, such as may occur in root areas of open butt joints, there is a danger of martensitic formation within the austenite and this structure exhibits brittleness at normal temperatures. Clearly, therefore, a 316L weld metal is not the ideal choice in this case. 2. The C/Mn structural steel to 308 stainless steel using 309L weld metal. The weld metal composition in this case indicated by plot (2) will be of austenite plus approximately 5% ferrite which is eminently suitable for the application. The delta ferrite will prevent the risk of hot cracking and dilution can be increased by as much as 50% before there is any danger of martensitic formation. Constitution diagram for stainless steel weld metal 30 0% 5% 10% Martenisitic cracking below 400 o C Nickel equivalent = % Ni + 30 x % C x % Mn A F + M A + M Martensite C Austentite M + F 1 B A + M + F Chromium equivalent = % Cr + % Mo x % Si x % Nb 2 Tubrod (316L) Tubrod (309L) Ferrite A + F 20% 40% 80% 100% Percentage of Ferrite Austenite hot cracking above 1250 o C Brittleness after heat treatment at o C Ferrite high temperature brittleness

52 One sided welding and non fusible backing Combining the extra deposition available from cored wire with the use of nonfusible backing to permit one sided welding can result in considerable increases in productivity. The labour costs incurred with the application and removal of backing is more than recovered through considerably higher welding speeds over manual arc in particular. A wide variety of shapes and types are available Fig 16 and can be used with the majority of the Tubrod cored wires for welding in all positions. Fig 16 Penetration is controlled by the backing and not current control hence higher amperage can be used to maximise speed and deposition. Full fusion and smooth root penetration profile is achieved with no effort, thereby eliminating the need for backgouging and sealing runs. Plate fit-up and accuracy of edge preparation are not critical. Simplification of joint design is also possible realising further savings, for example, dispensing with the root face for butt welds. Very low moisture pick-up with ceramic types ensures low hydrogen weld metal and they can be rebaked if necessary. For added insurance glazed types are available for use in extreme conditions. Mechanical magnetic and adhesive type fixing methods cater for all common joint designs. To achieve full penetration in open butt welds in the flat position and without backing, it is necessary to use the dip transfer mode coupled with a high degree of vigilance on the part of the operator. Dip transfer also restricts the choice of wire types to fully basic E71T-5 OK Tubrod 15.00, or metal cored E70C OK Tubrod since rutile types only operate efficiently using spray transfer. The use of ceramic backing eliminates this problem, removing the restriction of choice and allowing the use of spray transfer. The root can, therefore, be completed in a fraction of the time and with minimal operator fatigue. With regard to positional welding and particularly the vertical position, fully basic and metal cored wires are limited to dip transfer throughout the joint. Ceramic backing can do little to improve welding speed in the root since both types of wire are capable of completing satisfactory full root penetration without backing using either the vertical up or downwards techniques. However, although the E71T-1 OK Tubrod type wires utilise the spray transfer mode, they are too fluid for adequate control in open butt situations without support. The use of ceramic backing will overcome this difficulty and permit perfect control at very high deposition rates of 3 kg/hr at 180A, in the case of 1.2mm. Fig 17. The higher arc energy available with cored wires also ensures that restarting and remelting of any crater defects is easily accomplished. A hot start device is therefore not required. Fig 17 Recommended edge preparations o Root gap Welding position: flat/vertical up Root gap 4-10mm Preferably 4-6mm o Root gap o Welding position: horizontal vertical Root gap 4-6mm Preferably 4-5mm

53 AWS classifications for cored wires Frequently working drawings specify consumable types to be used with designations taken from a classification system that has been formulated by a standards authority or society. For cored wires the most universally adopted system is that of the American Welding Society. This section is intended to provide the fabricator with a basic understanding of the AWS designations as they apply to Tubrod wires. The system divides cored wires into four sections as follows:- AWS A Carbon Steel Electrodes & Rods for Gas Shielded arc welding. AWS A AWS A AWS A Carbon Steel Electrodes for Flux Cored Arc Welding. Low Alloy Steel Electrodes for Flux Cored Arc Welding. Stainless Steel Electrodes for Flux Cored Arc Welding. Method of classification A This is a relatively new classification for solid wires and rods which now includes metal cored wires. E 70 C HZ N Y X Example: E70C - 6M - OK Tubrod E = Electrode 70 = Minimum UTS of 70,000 psi C = Metal Cored (composite electrode) 6 = Weld metal composition - A Table 2 M = 75% - 80% Argon + CO 2 Designates an electrode. Indicates the minimum tensile strength of deposited weld metal in units of 1000 psi. Indicates that the wire is composite i.e. tubular metal cored. Optional supplemented diffusible hydrogen designator. This suffix is only used when the phosphorous, vanadium and copper limits have been changed and indicates that the weld metal is suitable for nuclear reactor applications. Indicates the shielding gas for metal cored tubular wires. CO 2 shielding is indicated by C and 75% - 80% Argon plus CO 2 is indicated by M. Indicates the chemical composition of the weld metal. The use of the suffix GS will mean that the wire is intended for only single pass welding. Method of classification A E X X T X M Designates an Electrode. Indicates the minimum tensile strength of deposited weld metal in units of 10,000 psi. Indicates the primary position for which the electrode is designed. 0 = Flat and horizontal positions. 1 = All positions. Indicates a flux cored electrode. Indicates performance and usability capabilities. Indicates for use with mixed gas. Example: E71T-1M = Tubrod E = Electrode 7 = Minimum UTS of 70,000 psi 1 = All positions T = Flux cored electrode 1 = Electrode classified for use with CO 2 or may be used with Argon CO 2 mixtures to improve usability, especially for out of position welding. Designed for single and multipass welding and characterised by spray transfer, low spatter loss and a moderate volume of slag. Electrodes of this type are generally rutile bases and operate with DC electrode positive. M = Mixed gas ie. Ar + 20% CO 2 Note: the suffix M is omitted when the wire is designed for CO 2 only. If the wire is designed for mixed gas and CO 2 then both designations will apply, for example, E71T-1M, E71T-1.

54 Performance and Usability Capabilities - Tubrod Range T1 = Tubrod 15.12, and Characteristics described in example on previous page. T4 = Tubrod Self shielded electrode for single and multipass welding in the flat and horizontal vertical positions. Using DC electrode positive a globular type metal transfer is produced. T5 = Tubrod Designed for use with CO 2 (Argon based gases may be used as in T1) for single and multi-pass welding in the flat and horizontal positions. Electrodes of this group have a lime fluoride based slag and produce weld metal having improved impact properties and crack resistance in comparison to rutile types. T7 = Tubrod Self shielded for operation on DC electrode negative, the slag system is designed such that the smaller sizes can be used for all positional welding. Used for single and multi-pass welding. Note: Some electrodes are designed for all positions in the small sizes with flat and horizontal vertical in the larger sizes. The mandatory section of the specification allows dual classification for the primary positions for these types. An example is Tubrod mm - 1.4mm = E71T-5M 2.4mm - 3.2mm = E70T-5M Low Alloy A This specification is the same as that for carbon steel in respect to mechanical properties, welding positions, usability and performance data. The alloy content is shown by a suffix. Example: Tubrod = E81T1-Ni1. Listed below are the suffixes applicable to the Tubrod range. Ni1 - Nickel 0.80/1.10% Ni2 - Nickel 1.75/2.75% C.Mn Low temperature service K3 - Nickel 1.25/2.60% Molybdenum 0.25/0.65% High tensile steels A1 - Molybdenum 0.40/0.65% High tensile steels B2 - Chromium 1.00/1.50% Molybdenum 0.40/0.65% B3 - Chromium 2.00/2.50% Molybdenum 0.90/1.20% Creep resisting steels Stainless Steel A This classification which relates to stainless steel wires is quite easy to understand in that there are only three principal designations. The other parts such as E and T follow the standard pattern in other AWS specifications. The chemical composition is identified by internationally recognised AISI numbering system followed in some cases by an additional letter such as L for low carbon. This classification replaces the A and has been extended to include welding positions as follows: Indicates a welding electrode Designates weld metal composition Designates a cored wire Recommended welding positions 0 = Flat and Horizontal 1 = All positions Indicates shielding gas EXXXTX-X 1 = CO 2 3 = None 4 = 75-80%Ar+CO 2 5 = 100% Ar Example : OK Tubrod = E308LT1-4

55 European Standard EN 758: 1997 Tubular cored electrodes for metal arc welding with and without shielding gas of non-alloy and fine grain steels With the introduction of this new standard all EU countries are required to adopt EN 758 and withdraw all individual national standards previously used. In future the standards authorities within the countries which comprise the EU will publish EN 758 with their own prefix. Thus in Germany, for example, it will become DIN EN 857 and BS EN 758 in the UK. The only difference in the contents of the standards will be the language in which they are printed. Important: There are two significant differences between the EN standard and the AWS classification system A Firstly, the designation that relates to strength in the EN system is based on YIELD strength (or 0.2% proof) not the UTS of the deposited weld metal. Secondly, EN 758, although covering cored wires for the welding of non-alloy and fine grain steels up to 500 N/mm2 yield strength, does contain low alloy wires. A number of plain carbonmanganese steels are capable of high impact properties at -40 C and below but the toughness given by a wire of similar composition would be extremely procedure-sensitive. For such circumstances Ni and Mo bearing wires are included within this EN standard. In the AWS system, however, there is a separate standard for low alloy wires i.e. A Method of Classification EN 758 T Ni B M 4 H5 optional part hydrogen symbol welding position shielding gas core characteristics chemical composition impact properties strength and elongation tubular electrode standard number Compulsory Symbols Symbol for strength and elongation EN Symbol Yield strength Tensile strength Elongation % N/mm 2 N/mm min min min min min min min min min min Symbol for toughness EN Symbol Temperature for 47J, C Z no requirement A +20 C 0 0 C 2-20 C 3-30 C 4-40 C 5-50 C 6-60 C Symbol for alloy content Alloy symbol Mn Ni Mo No symbol Mo MnMo Ni Ni Ni Ni Mn1Ni NiMo Z Any other composition 1) If not specified : Mo<0.2, Ni<0.5, Cr<0.2, V<0.08, Nb<0.05, Cu<0.3 and for electrodes without a gas shield A1<2.0 2) Single values shown in the table are maximum values

56 Description of core Symbol EN 758 gas-shielded R P B M self-shielded U V W X Y Z S Rutile base, slow freezing slag Rutile base, fast freezing slag Basic slag Metal powder core Rutile or basic/fluoride Basic/fluoride, slow freezing slag Basic/fluoride, fast freezing slag Other types Shielding gas EN 758 Symbol M Argon mixture M2 C CO 2 N No shielding gas Optional symbols Welding position Symbol EN 758 Positions 0 (not used) 1 All positions 2 All positions except vertical down 3 Flat butt welds, flat & HV fillets 4 Flat butt & fillet welds 5 As for (3) and vertical down 9 (not used) Symbol for hydrogen content of deposited metal Symbol H5 H10 H15 Diffusible hydrogen, ml/100g deposited metal 5 max 10 max 15 max When the letter H is included in the classification the manufacturer shall state... what restrictions need to be placed on the conditions of storage and on current, arc voltage, electrode extension, polarity and shielding gas to remain within [the quoted] limit. Example : OK Tubrod = T Ni P M T = Tubular electrode 50 = Yield strength - min 500 N/mm2 6 = Toughness - min 47J at -60 C 2Ni = Alloy = 1.8% - 2.6% Ni P = Positional rutile M = Mixed gas

57 Cored wire alternatives to manual metal arc Metal Cored Wire Manual Arc AWS Metal Cored Wire AWS E6012 OK Tubrod E70C-3M E6013 OK Tubrod E70C-6M/6C E7024 OK Tubrod E706-6M E7016 E7018 E7028 } } } } } OK Tubrod E70C-3M OK Tubrod E70C-6M/6C OK Tubrod E70C-6M OK Tubrod E70C-GM E7016-A1 E7018-A1 OK Tubrod E80C-G E8016-G E8016-C3 OK Tubrod E70C-G E8016-C1 OK Tubrod E70C-Ni2 E9018 OK Tubrod E91TX-G E11018 OK Tubrod E111TX-K3 Note: The weld metal from some unalloyed E7016 manual arc electrodes are capable of high toughness at -40 o C and -50 o C. In similar circumstances select OK Tubrod Flux Cored Wire Manual Arc AWS Flux Cored Wire AWS E6012 E6013 E7024 } { } OK Tubrod OK Tubrod OK Tubrod OK Tubrod OK Tubrod OK Tubrod OK Tubrod OK Tubrod E70T-1 E70T-1M, E70T-1 E71T-1, E71T-1M E70T-1 E70T-1M, E70T-1 E7018 OK Tubrod E71T-5, E71T-5M OK Tubrod E71T-5M E7016 OK Tubrod E81T1-Ni1 E8016 G OK Tubrod E80T5-Ni1 E8016-C1 OK Tubrod E81T1-Ni2 OK Tubrod E70T5-G E8016-C3 OK Tubrod E81T1-Ni1 E9018 OK Tubrod E81T1-Ni1 OK Tubrod E90T5-K2 E8018-B2 OK Tubrod E80T5-B2 E9018-B3 OK Tubrod E90T5-B3 E11018 OK Tubrod E110T5-G } } } Note: Under certain conditions E7016 and E7018 manual arc electrodes may be substituted by OK Tubrod or OK Tubrod Where an E7016 is used for service at -40 o C select OK Tubrod

58 Cored wire fault finding FAULT POSSIBLE CAUSE REMEDY POROSITY Insufficient shielding gas Check recommended flow rate Excessive electrode extension Gas Nozzle too short Plate condition and impurities Equipment fault on gas control Reduce extension - refer to notes Replace Remove non-metallic substances Check for leaks and air ingestion POOR WIRE FEED Incorrect tip size Check and replace Damaged liner or tip Incorrect type, size and pressure of feed rolls Spool brake too tight Blocked liner Replace Refer to equipment manual Check tension and slacken if necessary Remove obstruction or replace SLAG INCLUSIONS Incorrect welder technique Refer to notes Direction of travel Refer to recommended technique UNDERCUT Travel speed too fast Reduce travel speed or check parameters Incorrect torch angle Voltage too high Refer to notes on torch angles Reduce voltage LACK OF PENETRATION Current too low Increase current Electrode extension too long for current being used Incorrect or inconsistent travel speed Torch angle or direction of travel Narrow joint preparation Roof face too large Refer to notes on electrode extension Adjust travel speed to suit desired degree of penetration Refer to welding techniques Modify preparation Modify preparation LACK OF FUSION Direction and speed of travel Refer to notes/illustrations Incorrect torch angle Incorrect parameters or torch manipulation Refer to notes/illustrations Check against recommended values for the wire in question and notes on torch manipulation EXCESSIVE SPATTER Dirty plate Clean plate - wire brush or grinding Voltage too high for amperage Shielding gas pressure too high poor current pick-up Check against recommended values Check against recommended flow rates Check size or replace worn contact tip

59 Cored wire selection Mild and Medium Tensile Steels Ambient Temps +20 O C/0 O C Metal cored high productivity Rutile flux cored general purpose Basic flux cored high mech props Rutile flux cored heavy deposition >4mm mm >8mm 1.6mm >12mm 2.4mm >4mm 1.2mm >6mm 1.4mm >8mm 1.6mm >4mm 1.2mm >8mm 1.6mm >12mm 2.4mm >4mm mm >12mm mm Ar+CO 2 Ar+CO 2 Ar+CO 2 CO 2 OK14.00 OK14.12 OK14.13 OK15.14 OK15.15 OK15.00 OK15.02 OK15.10 OK15.12 Ar+CO 2 CO 2 OK14.12 Easy to use. Max versatility. Minimal slag. One current setting. Very low fume. OK Grade 2. OK Grade 3. DC+, DC-. CO 2 OK15.14 Easy to use. All positions. Spray transfer. Ideal on ceramic. Excellent vert' up Grade 3 Low H 2 DC+. CO 2 OK15.00 OK15.02 Fully basic. Extra low H 2. High purity. X-ray quality. Grade 3. Tolerant to plate condition. DC-. OK15.18 Max deposition. Self deslagging. Excellent finish. High welder appeal. Grade 2. DC+.

60 Mild and Medium Tensile Steels Low Temperature Service -20 O C -30 O C (-40 O C) -60 O C 560 N/mm N/mm N/mm 2 Metal Rutile Basic Metal Rutile Basic Metal Rutile Basic OK OK OK OK OK OK OK OK OK OK OK OK OK High Yield and Low Alloy Steels Weathering O C High Yield Creep >550 N/mm 2 Resisting <12mm >12mm Metal Rutile Basic 0.5 Mo Metal Rutile OK OK Basic OK OK Ni can be used as sub for Cu -20 O C OK O C OK O C OK >700 N/mm 2-50 O C OK OK OK Cr 0.5 Mo If matching composition demanded Metal Rutile Basic Metal Basic OK Cr 1 Mo OK OK OK OK O C OK O C OK OK 15.22

61 Welding equipment When proposing to adopt cored wire welding it is essential to review all aspects of the total process in order to maximise the benefits. Large numbers of MIG equipment are operating in the various fields of metal fabrication, but the majority of these and particularly the earlier types were principly designed for use with solid wire. They produce excellent results in terms of reliability and electrical characteristics relative to this type of wire, but many are not mechanically suitable or electrically versatile enough to optimise the use of cored wires. Equipment considerations Output of existing equipment - does the power source have sufficient amperage capacity to fully utilise the current range of the proposed wire? The minimum will be around 350A for 1.0, 1.2mm wires and up to 600A for 2.4mm. The duty cycle of the proposed power source - is it sufficient? Ideally 60% should be the minimum for the largest size of wire likely to be used. The torch - is the duty cycle of this very important item high enough relative to the operating amperage and particularly in relation to argon rich gas if a change from CO 2 is envisaged? Liners - some users prefer teflon or nylon type liners when operating with solid wires. When welding with cored wires it is recommended that only the steel spiral type are used with an attendant reduction in friction and hence smoother feeding. Water cooling - could this be an advantage? Modern water cooled torches are smaller, more flexible with less weight and certainly less fatiguing from an operator s viewpoint. Polarity - does the power source have the facility for a change of polarity? Some types of cored wires benefit from the use of negative pole. Wire feeder - some units only have a single pair of drive rolls which although often satisfactory for 1.0 and 1.2mm wires will almost certainly lead to difficulties if attempts are made to use 1.6mm and 2.4mm sizes. For large sizes tandom and geared four roll drives are preferred. Feed rolls - smooth grooved rolls are satisfactory for the 10mm, 1.2mm and often 1.4mm but are not considered sufficiently positive for 1.6mm up to 3.2mm. The large sizes benefit from the use of knurled rolls which exert a good grip but with minimum pressure and consequently reduce the risk of crushing or distortion of the wire. Should fume extraction be considered? If the proposed wire is a large diameter flux cored type the volume of fume will be greater than that produced by solid wire. The investment in fume extraction is small compared to the enormous improvement in the working environment. Electronic control Modern MIG welding equipment embodies the most advanced electronic control systems and provides significant benefits in efficiency. When viewed against total welding costs (especially labour cost) and weighed against the increased productivity provided by cored wires, the cost of investment in new equipment is less than that for the consumables, and may be paid back in a few months. Automatic electronic feed back control maintains the wire feed at a constant level regardless of voltage conditions. When using dip transfer which is characterised by higher spatter levels than with spray transfer, the improved electronic controlled inductance systems can reduce this weld metal wastage by producing a smoother arc and metal transfer through precise control of peak short circuiting current. Thyristor controlled power sources ensure greater control of output at pre-set levels with steplessly variable voltage control so that parameters can be obtained to suit any application. They can also be controlled remotely. Wire feeders are available with creep starting facilities to assist arc initiation and some have preprogrammable selection once set. In addition this type has the facility to operate at long distances and a wider working radius. Some types also permit the use of 5Kg reels which allow greater portability and accessibility. Inverters The weight of a conventional MIG/MAG power source is directly related to the frequency of the mains supply. If, therefore, the frequency can be increased, the weight of the transformer will be reduced and it is this fundamental principle that is the basis of inverter power sources. The threephase AC supply is rectified to form a DC current and then convert back to AC by an inverter, but at a much higher frequency than that of the mains supply. It is then transformed and rectified again to provide a DC supply suitable for welding. The entire process is backed up by a control system that provides the power source with all the necessary static and dynamic properties. Apparent from the low weight and portability there are advantages to be gained from the exceptional welding characteristics provided by an extremely stable arc and minimal spatter loss. Compared to conventional thyristor controlled units, the starting time is almost halved and this relates to the time taken from initial strike to full arc stability. The inverter power sources is particularly beneficial to the jobbing fabricator because of its versatility. With the aid of various add-on units, including pulsing, they can be adapted for MIG/MAG, TIG and MMA which together with the advantage of stepless parameter control can cater for the widest possible range of materials.

62 OK Tubrod submerged arc welding Alloyed cored wires for use with the submerged arc welding process have been available for many years. Cored wires represent the least expensive means of producing a weld metal of complex composition compared with solid wire which may be unavailable, highly expensive or impossible to produce. Hard-surfacing wires are typical examples and to a lesser extent the low alloy joining wires, but the common advantage which is disregarded under such circumstances is productivity. It can be seen that the difference in deposition rate between gas shielded solid and cored wires will widen disproportionately upwards with increases in amperage in favour of cored wire. The normal current range for cored wire across the popular range of semi automatic sizes will be from 140A at the low end of a 1.2mm up to a maximum of 450A with a 2.4mm. In comparison an amperage of 450A with the submerged arc process would be considered low. The potential, therefore, for increased deposition rate with current levels in excess of 800A is enormous and can be up to 30% greater than that of solid wire of equivalent size and similar amperage. Consider the attributes of the OK Tubrod semiautomatic joining wires adapted for use with the submerged arc process in larger sizes. Summary of Benefits Deposition may be improved by up to 20% with the metal cored OK Tubrod 14.00S and up to 30% with the fully basic flux cored OK Tubrod 15.00S. The effect on productivity is, of course, dramatic, paving the way for considerable cost savings. The C/Mn wires will produce vastly superior mechanical properties than the standard S1 and S2 type solid wires commonly used throughout industry. Comparatively higher heat inputs, together with fewer passes, can be adopted leading to additional economies in total welding time. In addition, the integrity of OK Tubrod 15.00S weld metal is maintained after stress relief, even down to -30 C, which is a significant benefit. The OK Tubrod wires are universally approved to Grade 3 by all major certification authorities using both AC and DC. Apart from single wire operation they can be used successfully for twin wire, multi-power, single and two sided welding as well as fillet welding. kg/hr kg/hr They impose very few limitations with regard to their application, allowing a wide range of industries to enjoy the advantages afforded. An improved tolerance to plate condition with a process that is characterised by significant problems when solid wire is used. Shipbuilders, for example, have the need to weld over shop primers at high travel speeds without porosity. Deposition rate comparison OK 14.00S and OK OK flux Current (A) Deposition rate comparison OK 15.00S and OK OK flux S 2.4mm 14.00S 3mm 14.00S 4mm mm mm mm 15.00S 2.4mm 15.00S 3mm 15.00S 4mm mm mm mm Current (A) KG/HR Under such conditions the travel speed achieved with solid wire will generally be surpassed with cored wires, especially the fully basic OK Tubrod 15.00S. Apart from those for mild and medium tensile steels, wires are available for applications required for service down to -60 o C and low alloy types for high tensile single sided single pass butt welding, also with good sub-zero notch toughness. Twin wire deposition comparison OK Tubrod 14.00S + OK OK Tubrod 15.00S + OK OK Autrod OK AMPS 15.00S 2 x 2.4mm 14.00S 2 x 2.4mm x 2.5mm

63 OK Tubrod 14.00S A Metal cored wire designed specifically for use with submerged arc welding process in conjunction with OK flux. Classification (with OK flux) AWS A : F7A2-EC1 Applications OK Tubrod 14.00S is used for the welding of mild and medium tensile steels and is recommended for single and multi-pass fillet welding. Exceptional productivity can be achieved at deposition rates up to 20% higher than with the same size of solid wire at the same current. OK Tubrod 14.00S exhibits excellent mechanical properties compared with equivalent solid wires. This product is suitable for single and twin wire welding applications. OK Tubrod 14.00S can also be used with OK flux to give faster welding speeds together with superior weld appearance for fillet welding. Where toughness properties below 0 o C are required, then OK flux should be used. Welding data DC+ (Single wire) Diameter Current Amps Volts Typical weld metal composition (OK flux) C Si Mn Mechanical properties - All weld metal specimens Yield stress 450 N/mm 2 Tensile strength 530 N/mm 2 Elongation 30% Charpy V impact values Test temp Typical -20 o C 120J Approvals (with OK flux) ABS 3M, 3YM LR 3M, 3YM DNV IIIYM BV A3YM GL 3YM TUV Eignungsgeprüft DB OK Tubrod 14.02S A metal cored wire producing a 0.5% Mo weld metal for the submerged arc welding of high tensile steels. Designed for use with OK flux it can be used for high speed fillet welding as well as multi-pass butt joints. As an alternative to an S2Mo solid wire, it offers superior deposition rates and mechanical properties, especially notch toughness. Classification (with OK flux) AWS A : F7AZ-ECA4-A4 Applications All general fabrication of high tensile fine grained steels where submerged arc is appropriate. Boilers, pressure vessels in process plant are typical examples. A typical application within the power industry is the high speed fillet welding of tubes to fins. Suitable for service up to 500 o C. Welding data DC+ (Single wire) Diameter Current Amps Volts Typical weld metal composition (OK flux) C Si Mn Mo Mechanical properties - All weld metal specimens Yield stress (0.2% PS) 520 N/mm 2 Tensile strength 570 N/mm 2 Elongation 28% OK Tubrod 14.07S A metal cored wire for the submerged arc welding of 1.25Cr 0.5Mo type creep resisting steels. Used with OK fully basic flux the weld metal is of the highest metallurgical integrity for service temperatures up to 500 o C. The wire may also be used with OK flux for fillet welding applications. Classification (with OK flux) AWS A : F7AZ-ECB2-B2 Applications Steels of similar composition as used in steam boilers, process plant and piping, together with pressure vessels in the power generation industry. This product has been successfully used in tube to fin applications with OK flux. Preheating dependent on thickness up to 300 o C is essential followed by post weld heat treatment at o C. Welding data DC+ (Single wire) Diameter Current Amps Volts Typical weld metal composition (OK flux) C Si Mn P S Cr Mo Mechanical properties - All weld metal specimens Yield stress 620 MPa Tensile strength 700 MPa Elongation 26%

64 OK Tubrod 14.08S A metal cored wire for the submerged arc welding of 2.25Cr 1Mo type creep resisting steels, where creep strength at service temperatures up to 650 o C.is required. It is designed for use with OK flux for optimum creep rupture strength and minimum hydrogen levels but may also be used with OK flux for less critical applications. Applications Highly stressed components of similar composition and required for service at elevated temperatures. These will be found in the construction of process and petrochemical plant, as well as with power generation industry for turbines, pressure vessels and piping. Welding data DC+ (Single wire) Diameter Current Amps Volts Typical weld metal composition (OK flux) C Si Mn P S Cr Mo Mechanical properties - All weld metal specimens Yield stress 600 N/mm 2 Tensile strength 670 N/mm 2 Elongation 20% OK Tubrod 15.00S A basic flux cored wire especially formulated for use with the submerged arc process and OK flux. It produces high impact values from welded joints and compared to those of solid wire can utilise higher heat inputs and fewer passes. Classification (with OK flux) AWS A : F7A4-EC1 Applications OK Tubrod 15.00S is preferred when high integrity welded joints are required in mild and medium tensile steels. General fabrication, structural engineering and shipbuilding are the principal areas of application. The welding of primed plate at high speeds is of particular benefit. Deposition rates are up to 30% higher than solid wire for the equivalent size and the same current. This wire is suitable for single wire, twin arc and multi-power systems and can also be used with iron powder additions. Where optimal weld appearance and welding speed is required, OK flux can be used but is not recommended for applications below -20 o C. For optimum low temperature toughness down to -40 o C, OK flux can be successfully used. Where approvals and classifications are required OK flux must be used. Welding data DC+ (Single wire) Diameter Current Amps Volts Typical weld metal composition (OK flux) C Si Mn Mechanical properties - All weld metal specimens Yield stress 460 N/mm 2 Tensile strength 540 N/mm 2 Elongation 30% Charpy V impact values Test temp Typical -40 o C 130J Approvals (with OK flux) ABS 3M, 3YM LR 3M, 3YM DNV IIIYM BV A3YM GL 3YM DB TUV Eignungsgeprüft Co OK Tubrod 15.21S A basic flux cored wire used in conjunction with OK flux for the submerged arc welding of high tensile steels. The weld metal is alloyed with 0.5% Mo which allows a very wide range of applications including elevated temperatures up to 500 o C. The fully basic formulation ensures a very tough, high quality weld deposit. Classification (with OK flux) AWS A F7A2-ECA4-A4 Applications Typical examples are structural steelwork, pressure vessels and piping, cranes, contractors plant etc. It is also ideally suitable for the rebuilding of marine engine piston crowns. Welding data DC+ (Single wire) Diameter Current Amps Volts Typical weld metal composition (OK flux) C Si Mn P S Mo Mechanical properties - All weld metal specimens Yield stress 460 MPa Tensile strength 550 MPa Elongation 30% Charpy V impact values Test temp Typical -30 o C 120J

65 OK Tubrod 15.23S A basic cored wire for the submerged arc welding of 9% Cr creep resisting steels, in conjunction with OK low phosphorus fully basic agglomerated flux. This combination will provide a composition compatible with that of the base materials such as ASTM A335 grade P91. The formulation of the wire ensures excellent weldability with high productivity. Applications The principal areas of application are in the power generation and petrochemical industries for high temperature and pressure service. Piping, pressure vessels and turbine diaphragms are typical examples. A minimum preheat of 150 o C with a maximum interpass of 300 o C is required and post weld heat treatment at 760 o C is recommended. Welding data: DC+ (Single wire) Diameter Current Amps Volts Typical weld metal composition (OK flux) C Si Mn Cr Mo Ni Nb V N Mechanical properties - All weld metal specimens Yield stress (0.2% PS) 610 N/mm 2 Tensile strength 720 N/mm 2 Elongation 26% Charpy V impact values Test temp Typical +20 o C 50J OK Tubrod 15.24S A basic flux cored wire for the submerged arc welding of structural steels for service down to -50 o C. The weld metal contains a nominal 1% Ni and combines excellent low temperature toughness with a minimum yield of 450 N/mm 2 in both the as-welded and stress relieved conditions. Used with OK the mechanical properties are maintained at high heat inputs and the CTOD performance is impressive. Deposition rates can be up to 30% higher than with the equivalent size of solid wire at similar currents. Classification (with OK flux) AWS A : F8A6 EC-G Applications All structural steel applications, particularly offshore constructions and pressure vessels required for service down to -50 o C. Using a multipass technique the number of passes may be reduced in comparison to solid wire and the weld metal is equally dependable using single, twin wire or multi-power modes. Welding data DC+ (Single wire) Diameter Current Amps Volts Typical weld metal composition (OK flux) C Si Mn Ni Mechanical properties - All weld metal specimens Yield stress (0.2% PS) 530 N/mm 2 Tensile strength 620 N/mm2 Elongation 26% Charpy V impact values Test temp Typical -50 o C 130J OK Tubrod 15.25S A 2.5% Ni basic cored wire introduced for use with the submerged arc process in conjunction with OK flux. It is used for welded joints requiring charpy V values down to -60 o C combined with the minimum number of passes and high heat inputs. Classification (with OK flux) AWS A : F7A8-ECNi 2-Ni2 Applications General, structural and offshore fabrication together with shipbuilding are the main application areas where charpy V values down to -60 o C are required. It also has a high tolerance to shop primer when welding high speed fillets as well as single-sided, single pass butt joints. The wire has no mode limitations in that it can be used single wire, twin arc and multi-power. Welding data DC+ (Single wire) Diameter Current Amps Volts Typical weld metal composition (OK flux) C Si Mn Ni Mechanical properties - All weld metal specimens Yield stress 500 N/mm 2 Tensile strength 580 N/mm 2 Elongation 28% Charpy V impact values Test temp Typical -60 o C 120J

66 Operating conditions OK Tubrod 14.53S A metal cored wire designed especially for submerged arc welding of high dilution fine grained steels of up to 550 N/mm 2 yield strength, where excellent toughness is required to -60 o C. Used with OK flux it has a very high tolerance to heat input and performs well on both thick and thin plate. The results are achieved through controlled alloying and a chemical buffering system for the nucleation of acicular ferrite. As the wire is alloyed to match the parent material properties under conditions of high dilution, the allweld metal yield and tensile strengths exceed those of the base material. Classification AWS A F9A2-EC-G Applications All general fabrications and structural work where good sub-zero toughness is required from high dilution two-pass welding. Such applications will include LNG bulk carriers and ice-breaking ships. Welding data DC+ (Single wire) Diameter Current Amps Volts Typical weld metal composition (OK flux) C Si Mn Ni Mo Mechanical properties - All weld metal specimens Yield stress 0.2% 620 N/mm 2 Tensile strength 690 N/mm 2 Elongation 25% Charpy V impact values (all weld metal) Test temp Typical -30 o C 60J In a high dilution butt joint -60 o C 40J OK Tubrod 14.54S A metal cored tubular wire developed for submerged arc welding of structural steels, having a minimum yield strength 550 N/mm 2. Used with OK flux it has a very high tolerance to heat input variations, the weld metal producing 100J at -40 o C even at 6kJ/mm. With a nominal composition of 1.3 Ni, 0.5 Mo it also contains non-metallic additions to improve performance and reduce hydrogen levels. Applications All structural work involving high yield steels of not less than 550 N/mm 2. These steels will include NQ1, OX540E, OX542, OX602, SE500, DOMEX 480 and HY80. Typical examples involving these steels will be bridges, offshore jack-up structures, earth moving equipment and cranes. Classification AWS A F9A4-EC-G Welding data DC+ (Single wire) Diameter Current Amps Volts Typical weld metal composition (OK flux) C Si Mn Ni Mo Mechanical properties - All weld metal specimens Yield stress 0.2% 580 N/mm 2 Tensile strength 690 N/mm 2 Elongation 28% Charpy V impact values Test temp Typical -40 o C 130J The operation of OK Tubrod cored wires with the submerged arc process is similar to that of solid wire from a practical point of view. There are, however, various factors to keep in mind when selecting parameters, as the same amperage, voltage and speed used for a given size of solid wire will not necessarily be the same for the cored wire. The principal reason for this is the fact that the amperages used for submerged arc will cause the cored wire to burn off at a significantly faster rate. Prospective users will obviously want to capitalise on this feature yet maintain the weld deposit geometry achieved with solid wire. An appreciation of the effect of variables is, therefore, desirable. Voltage Fundamentally, variations in voltage have the same effect on cored wires and solid wires, in respect of weld deposit profile and surface appearance. For example increasing voltage for a given amperage will produce: A flat deposit of increased width in butt joints and a concave profile in the case of fillet joints. Less penetration in all situations. Increased flux consumption and in extreme cases the Mn content depending on the flux type. Improve tolerance to fit-up variances. Difficult slag removal especially in the root area of butt joints due to undercutting. A progressive reduction in voltage will have the opposite effect producing a narrower bead with excessive reinforcement and deeper penetration. It is the latter, very important, feature that differs in respect to cored wires in that for a given voltage the penetration will be less and will have to be kept in mind when establishing parameters and plate preparation. This is particularly important for square edge butt joints and will be discussed later. There are occasions, however, when making high speed HV fillet joints that a high reinforcement will require a reduction in voltage to flatten the weld. The need is usually recognised by a high reinforcement accompanied by intermittent undercut when, for example, establishing parameters for a 3mm T fillet at a travel speed in excess of 1 metre per minute. Conversely, if the profile has excessive reinforcement with continuous undercut it is normally an indication that increased voltage will smooth out the profile.

67 Amperage Cored wires in the OK Tubrod 14.XXS and 15.XXS series may be used with either DC+, DC- or AC. DC+, however, is the most popular current type and is the preferred choice for cored wires. A high deposition rate and superior penetration can be achieved with DC+. Solid wire will give a higher deposition rate in the medium current range than cored wires using DC- but this is not used for joining under normal circumstances. The benefit with DCpolarity is in surfacing applications where dilution with the base material is minimal but build-up is optimised. The third type of current used with submerged arc is AC but it has few advantages and is in the minority except for when it is used as a necessity in multi-wire situations. At low currents, with single wire operation, the arc has a tendency for instability, particularly with the more basic fluxes, although it can be used to advantage if arc blow becomes a problem with DC. This is a phenomena caused by an interaction of magnetic fields pushing the arc in differing directions and normally associated with fabrications of complex design. Penetration The depth of penetration per amp with OK Tubrod submerged arc wires will always be less than that achieved with solid wire. Due consideration must be given to this when establishing suitable parameters for the root area of joints and also for square edge butt joints. An increase in amperage or reduction in voltage will not produce the same depth of penetration as solid wire of equivalent size. Increased amperage with solid wire will give deeper penetration but with an attendant progressive reduction in width Fig 18 which results in an unacceptable depth to width ratio. Such a profile is highly susceptible to solidification cracking. Fig 18 It can be seen in Fig 19 that the penetration profile with cored wire has a much rounder appearance and as such has a superior depth to width ratio and is therefore highly resistant to cracking. A study of columnar crystal formation of both weld deposits clearly shows the difference in the angles of convergence in the center of the weld. The cored wire pattern of solidification is less inclined to promote center line segregation of harmful residual elements which causes the cracking, especially under conditions of restraint. Fig 19 The rounded penetration profile of the cored wire can also be turned to practical advantage in the case of the two sided square edge butt joints Fig 20. If the joint tracking and preparation are inconsistent then the finger type penetration shape of solid wire could miss in the middle resulting in an unwelded area. The shape of the cored wire penetration with its greater width will have a margin for error in this regard and eliminate expensive repairs. Fig 20 One sided welding on non consumable backing is becoming increasingly popular because of the savings in plate turning and welding of the second side. A wider gap is obviously required to ensure adequate penetration on the under side which also allows a reduction in the included angles and depth of preparation. This in turn saves weld metal to fill the joint. The softer less penetrating arc with its more favourable width will ensure superior tolerance to fit-up variances allowing better control and consistency of penetration with a more acceptable profile Fig 21. Fig 21 Submerged Arc Fluxes All OK Tubrod wires for submerged arc are specially formulated for use with the process i.e. with modified silicon and manganese contents, but they should not be viewed in isolation as in the case with MIG/MAG types. The wires with submerged arc must be considered in combination with a flux and the type chosen for a given physical characteristic might not necessarily produce satisfactory mechanical properties. Alternatively, the tensile and yield strength are as required but the charpy V toughness is not adequate. It can be seen for example that when OK Tubrod 15.25S is used with OK Flux which has a basicity index of 1.6 the impact properties at -50 o C will be an average of 72J. If, however, this wire was used in conjunction with OK Flux with a basicity index of 3.4 the impact properties at the same -50 o C will be an average of 150J. This combination also exhibits exceptional CTOD performance - see typical welding procedure page 77. A small increase in tensile strength will occur from around 510 N/mm 2 up to 560 N/mm 2 but this is not significant since most authorities specify a minimum level, not a maximum. In the case of general fabrication where the user often satisfies himself that a particular combination attains mechanical properties for the intended purpose, then there are few limitations on fluxes. A case for consideration would be mass produced items for the automotive industry where OK Tubrod 14.00S might be used with OK Flux