High-strength heavy plates. Weight savings combined with excellent weldability. voestalpine Grobblech GmbH

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1 High-strength heavy plates Weight savings combined with excellent weldability voestalpine Grobblech GmbH

2 High-strength and wear-resistant steels voestalpine Grobblech quantity trend Quantity wear-resistant high-strength Business year Weight reduction achieved by high-strength steels Weight [%] S355 S460 S550 S690 S960 Strength grade Energy and mobility change our world. We have the materials. Our expertise meets customer requirements in demanding branches. We follow the dynamics of the markets and offer solutions to our customers to increase their performance. This is the mission of voestalpine Grobblech. For innovative solutions we use our technological experience from the energy branch. Moreover we are on top in processing technology especially in thermomechanical rolling. The result: our high-strength and wear-resistant steels. 2

3 The market High-strength steels are a strategic niche of voestalpine Grobblech with strong growth. We promote thermomechanically rolled highstrength steels and have developed a highly advanced online accelerated cooling process. This aims in high-strength heavy plates with excellent weldability, very high toughness and good surface. Typical fields of application Mobile cranes Concrete pump trucks Vehicles and trailers Mining equipments High-pressure pipes Offshore platforms 3

4 High-strength steels... double size means double stress... Things get bigger often double size. If you double the size of a construction (double length, width and height), then weight increases by factor 8 while the cross section is raised by factor 4. Therefore the stress in the component material is doubled. x 2 l w h length width height specific weight Weight: (2 l x 2 w x 2 h) x = x 8 Cross-section: (2 l x 2 w) = x 4 Stress: weight / cross-section = x 2 Why high-strength steels? High-strength steels can bear higher stresses than normalstrength steels. For a given load respectively a fixed stress in the component high-strength steels lead to smaller cross-sections and therefore to reduced weight which results in decreasing costs. Higher strength Smaller cross section Reduced weight Reduced costs 4

5 Cost benefits Reduced steel weight leads to Reduced purchasing volume Reduced costs for transport, assembly and foundations Reduced costs during further processing, especially in welding Less filler material Less welding time Less expense for checking the welds S mm Reduced thickness 24 % S mm Reduced weld volume 42 % Reduced thickness leads to superproportionally reduced weld volume. What about high strength? min. Yield strength Delivery voestalpine (MPa) condition brand Standard 355 NR, TMCP Medium strength TMCP High strength 700 TMCP 700 Q+T 960 TMCP+T NR normalising rolled TMCP thermomechanical control process Q+T quenched and tempered T tempered 5

6 TMCP TMCP- (Thermomechanical Control Process) steels are fine grain steels with High strength combined with high toughness Excellent weldability Best formability High reliability in welded structures High toughness in the heat-affected zone (HAZ) High resistance against cold cracks TMCP-steels from voestalpine Grobblech are produced with Very pure steel (low S-, P-, tramp element level) Low carbon content and low carbon equivalent (CE) Microalloying High-quality processing during melting, casting, rolling and accelerated cooling Different rolling and cooling processes TM1 TM2 ACC DIC Rolling Cooling TM Thermomechanical rolling Temperature T Nr Ar 3 MAE ACC DIC T T Nr Ar 1 Accelerated cooling Direct intensive cooling Tempering Recrystallisation-stop-temperature End of phase transformation Ar 1 M s (+T) Ar 3 M S MAE Start of phase transformation Martensite-start-temperature Microalloying elements 6

7 N + air cooling TM + air cooling TM + ACC TM + DIC S355 alform 420 M alform 500 M alform 500 M alform 700 M alform 960 M CE IIW =0.41 CE IIW =0.33 CE IIW =0.41 CE IIW =0.41 CE IIW =0.43 CE IIW =0.55 The effect of finer grain: higher strength higher toughness better weldability and formability 50 μm 50 μm 50 μm 50 μm 50 μm 50 μm 1,100 The same yield strength Yield strength [MPa] 1, CE = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15 according to IIW Cooling rate TM TM+ACC N TM+DIC QT + Alloying elements + Microalloying elements level is possible on different CE levels depending on the delivery condition. Low carbon equivalent (CE) is most important for good weldability. N Normalising rolled QT Quenched and tempered TM Thermomechanically rolled 300 plate thickness ACC DIC Accelerated cooled Direct intensive cooled Carbon equivalent CE Heat treatment and forming No heat treatment Normalising deteriorates the microstructure of TMCP-steels and thereby their properties. Hot forming and stress relief annealing TMCP-steels are generally intended to cold forming. Hot forming and stress relief annealing is possible up to 580 C. Mechanical properties may change due to heat input. 7

8 Applications of TMCP-steels voestalpine Grobblech has been among the pioneers in the field of the development of TMCP-steels. We have invested in the most modern accelerated cooling line in Europe and operate a highly advanced cooling process. Some 500,000 tons of TMCP-steels we produce year by year with increasing tendency. TMCP is our daily business. Thermomechanically rolled steels are widely used in different applications: Oil and gas pipelines onshore and in deepwater Offshore platforms Bridge building and mining equipments Buildings and structural steel work Mobile cranes and vehicles 8

9 Production route of TMCP-steels Our plates run online through water no heat treatment LD-converter Vacuum-degassing Continuous casting Plate rolling Accelerated cooling Plate finishing 9

10 TMCP-steels provide best weldability Low risk of cold cracks Due to the low-alloyed chemical composition and the low carbon equivalent (CE) TMCP-steels are perfectly weldable. Especially the low carbon content results in excellent resistance against cold cracks after welding. 0.4 Risk of cold cracks Carbon content [%] ZONE II Depends on conditions ZONE III High under all conditions ZONE I* Safe under most conditions Carbon equivalent CE *High strength welding consumables may require additional care CE = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15 according to IIW Fabrication benefits of TMPC-steels Remarkable reduction or elimination of preheating Great savings in fabrication costs Improved working environment for operators Reliable welded joint Almost no additional repair welding even without preheating High heat input welding Major reduction of welding pass Far lower welding costs Much shorter fabrication time Easier surface cleaning due to thin, homogeneous scale 10

11 For information about welding of voestalpine high-strength heavy plates please choose a Brand and follow the link sequence described: Böhler Welding Welding consumables for high demanding industries > Industry Focus > voestalpine high-strength heavy plates T-PUT welding solutions at its best > Products > Product Search > voestalpine high-strength heavy plates We are the World of Welding Solutions. 11

12 Brands We offer special high-strength heavy plates as voestalpine brands according to our technical terms of delivery. TMCP Thermomechanically rolled fine-grain steels Steel grades: alform 700 M alform 960 M Online production by thermomechanical rolling and accelerated cooling directly after hot rolling no bottle-neck. Quenched & tempered Quenched and tempered fine-grain steels Steel grades: aldur 700 Q aldur 700 QL aldur 700 QL1 Offline production by conventional quenching and tempering: annealing with subsequent water-quenching and following tempering. The double heat treatment may lead to a bottle-neck. 12

13 Benefits High-strength alform -steels are thermomechanically rolled and accelerated cooled. These special grades of voestalpine provide: Excellent cold formability Smaller edging radius compared to standard steels of same strength Best weldability Due to low carbon content and carbon equivalent Reduced preheating or even no preheating necessary Clean surface due to thin, homogeneous secondary scale Wide range of steel grades and dimensions Steel grades: alform 700 M up to alform 1100 M Thickness: mm Width: 900-2,500 mm Products voestalpine produces and delivers hot-rolled high-strength alform -steels in form of: Hot-rolled wide strips Sheets of hot-rolled wide strips Heavy plates The different production routes result in specific advantages of the different products. The exact properties and guaranteed values of these products you will find in the technical terms of delivery at and Hot strip mill Heavy plate mill 13

14 alform 700 M and alform 960 M heavy plates Thermomechanically rolled high-strength fine-grain steels with a minimum yield strength of 700 MPa and 960 MPa. voestalpine special grades alform 700 M and alform 960 M are mainly used in branches with a high extension of manufacturing, when weight savings are the main goals to reach. This is typical in the field of mobile cranes, concrete pump trucks and vehicles. 14

15 Production process alform -steels are produced by thermomechanical rolling with accelerated cooling directly after the rolling process. Conventional quenching and tempering in heating furnace and quenching device is no longer necessary. This type of steel provides a fine-grained, homogeneous structure with high tensile strength and excellent toughness. Benefits alform -steels show benefits in comparison with conventional quenched and tempered steels as following: Best weldability because of low C-equivalent, low C-content, easy edge preparation, reduced or abolished preheating, high resistance against cold cracks because of high toughness in the heat-affected zone (HAZ). Best bending properties because of the very fine grained structure, smallest bending radius and insensibility against cracks during bending. Best surface because of a homogeneous, thin secondary scale which is easily to remove. No scale scarred from hardening process. Dimensions Steel grade Min. Max. Thickness alform 700 M 8 mm 60 mm alform 960 M 10 mm 15 mm Width Length 2,500 mm 12,750 mm Weight per order item 20 mt Weight per plate 11.7 mt You will find more information in our technical terms of delivery. Subject to change pursuant to further development. The current version is available at 15

16 Chemical composition The lean chemical composition is designed for best weldability. Therefore we provide very low carbon- and carbon equivalent values. Heat analysis Guaranteed values mass % C Si Mn P S Al ges. Cr Mo Ni V Nb Ti B Steel grades max. max. max. max. max. min. max. max. max. max. max. max. max. alform 700 M alform 960 M Carbon equivalent Comparison of values for carbon content and carbon equivalent Thickness C CEV 1) CET 2) Steel grades Values mm % % % alform 700 M typical alform 700 M typical S690QL max alform 960 M typical S960QL max ) CEV = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15 according to IIW 2) CET = C + (Mn+Mo)/10 + (Cr+Cu)/20 + Ni/40 according to SEW

17 As-delivered condition Plates of alform 700 M are delivered in a thermomechanically rolled condition with accelerated cooling. Plates of alform 960 M are delivered in a thermomechanically rolled condition with accelerated cooling and tempering. Mechanical properties Yield Tensile Fracture Notch Plate strength strength 1) elongation 1) impact thickness YS min. TS Ratio A5 min. energy 2) min. Steel grades Values mm MPa MPa YS/TS % J , alform 700 M guaranteed > , > , typical S690QL acc. to EN guaranteed , alform 960 M typical 12 1,020 1, S960QL acc. to EN , ) Tensile test in accordance with EN on transverse samples. 2) Notch impact bending test in accordance with EN on Charpy-V longitudinal samples at 40 C. The mean value from 3 individual sampels must fullfil the specified requirements. No individual value below 70% of the guaranteed mean value. For thicknesses < 10 mm, samples similar to Charpy-V with dimensions of 10 x 7.5 mm are tested. The guaranteed value is reduced in proportion to the sample cross-section. 17

18 Safety at overload alform 700 M provide a low ratio of yield strength to tensile strength. This aims in additional safety in case of overload. Stress strain curves (detail) Item 1 With beginning overload alform 700 M strengthens safety alform 700 M more, but with less elongation than S690QL. Item 2 Increasing overload reaches the tensile strength for Stress [MPa] 800 S690QL S690QL while alform 700 M is still strengthening. Item 3 While alform 700 M is still strengthening, the tensile strength of S690QL is already passed. 600 Elongation Excellent toughness alform 700 M provide excellent toughness down to very low temperatures. Skillfully welded this aims also in high toughness in the heat-affected zone (HAZ) for a reliable welded joint. Typical toughness-temperature curves alform 700 M Notch impact energy [J] S690QL Testing temperature [ C] 18

19 Optimal Welding Reduced preheating The very low carbon- and carbon equivalent values reduce the preheating temperature significantly or even make preheating not necessary. This saves fabrication costs and improves the working environment of the operator. Preheating 160 CEV CET Minimum preheating temperature [ C] S690QL alform 700 M % % alform 700 M S690QL Calculation according to SEW 088: welding: MAW arc energy: 1.0 kj/mm H-content: 3 ml/100g welding material Plate thickness [mm] Lower hardening Due to the lean chemical composition the hardening in the heat-affected zone (HAZ) during welding ist remarkable lower compared with conventional quenched and tempered steels. This results in lower risk of cold cracks and a reliable welded joint. Hardening in heat-affected zone [HAZ] 475 C Mn CEV CET Max. hardness in HAZ [HV10] S690QL % % % % S690QL S690QL alform 700 M alform 700 M MAW welding, 12 mm thickness Arc energy [kj/mm] 19

20 Best bending properties The fine-grained structure of alform -steels provides very good cold formability. We recommend a minimum die-radius of: 3 x plate thickness for alform 700 M (EN : 4 x) 4 x plate thickness for alform 960 M (EN : 5 x) 100 Bending performance (crack length / bending length) x 100 [%] measured inner radius / thickness Tests for alform 700 M: plate thickness of 10 mm, bending direction parallel to rolling direction Less scale on surface Due to the TMCP online-production with accelerated cooling alform -plates provide a thin homogeneous scale. This results in less scale during processing in the costumer s workshop. 10 mm 10 mm Q+T steel plates: Quenching & tempering leads to thick scale from the furnace. During levelling there is a risk of getting marks of impressed scale. alform -plates: TMCP provides thin homogeneous scale from hot rolling. The risk of scale impressions is reduced. 20

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22 aldur 700 Q, QL, QL1 Quenched and tempered high-strength fine-grain steels with a minimum yield strength of 700 MPa. Quenched and tempered high-strength aldur -steels are used in advanced welded constructions. Weight reduction and reliabilty in operation at low temperatures are very important goals. aldur -steels are mainly used for mobile cranes and vehicles, mining and high-pressure pipes as well as for offshore applications. 22

23 Production process aldur -steels are melted according to the LD process (oxygen top blowing process). The combination of high strength and good toughness is achieved by water quenching and tempering. Benefits Higher tensile strength in comparison with common structural steels result in weight reduction. In the field of mobile cranes and vehicles higher payloads are possible. Cost efficient constructions give additional benefit. Excellent weldability as a result of low carbon equivalents: high resistance against cold cracks in the heat affected-zone (HAZ), lower preheating temperatures in processing and high reliability of components due to high toughness in the welded seam. Toughness We offer 3 different grades of toughness Design temperature aldur 700 Q 20 C aldur 700 QL 40 C aldur 700 QL1 60 C Dimensions Min. Max. Thickness 12 mm 100 mm Width 3,000 mm Length 12,750 mm Weight per order item 20 mt Weight per plate 11.7 mt You will find more information in our technical terms of delivery. Subject to change pursuant to further development. The current version is available at 23

24 Steel grades Designation according Steel grades to EN Material number aldur 700 Q S690Q aldur 700 QL S690QL aldur 700 QL1 S690QL Chemical composition Heat analysis Guaranteed values Steel grades mass % C Si Mn P S Al tot. N Cr Ni Mo Cu V Nb Ti B Zr max. max. max. max. max. min. max. max. max. max. max. max. max. max. max. max. aldur 700 Q, QL, QL Carbon equivalent Depending on the analysis employed, the following carbon equivalents result for varying plate thicknesses. Carbon equivalent % plate thickness in mm Steel grades < 30 > 30 < 50 > 50 < 70 > 70 < 100 aldur 700 Q, QL, QL1 CEV 1) max. acc. EN CEV 1) standard value CET 2) standard value ) CEV = C + Mn/6 + (Cr + Mo +V)/5 + (Ni + Cu)/15, carbon equivalent according to IIW 2) CET = C + (Mn + Mo)/10 + (Cr + Cu)/20 + Ni/40, carbon equivalent according to SEW 088 As-delivered condition Plates of aldur 700 Q, QL and QL1 are delivered in water-quenched and tempered condition. Direct hardening after hot rolling is permitted. 24

25 Mechanical properties Mechanical properties at ambient temperature Yield strength YS Tensile stength TS Fracture elongation MPa, min. MPa A5 Material plate thickness in mm plate thickness in mm min. Steel grades number < 50 > 50 < 100 < 50 > 50 < 100 % aldur 700 Q aldur 700 QL aldur 700 QL Notch impact energy Notch impact enery AV Sample J, min. Steel grades direction testing temperature in C aldur 700 Q longitudinal aldur 700 QL longitudinal aldur 700 QL1 longitudinal Bending We recommend a minimum die-radius of 4 x plate thickness. 25

26 26 Our clients are our partners

27 Your partners for a successful business From left to right: Günther Reiter Quality guenther.reiter@voestalpine.com Wolfgang Reisinger Logistics wolfgang.r.reisinger@voestalpine.com Rupert Egger R&D rupert.egger@voestalpine.com Gerhard Nöbauer Production gerhard.noebauer@voestalpine.com Franz Thurn Sales franz.thurn@voestalpine.com Christian Fischer Marketing christian.fischer@voestalpine.com A product management team takes special care of high-strength steels and customers. International sales organisation Being close to the customer is about more than just physical presence it s about really being there when the he or she needs you. voestalpine Eurostahl GmbH supports its customers in their efforts to meet ever harder challenges as and when they need it. As a reliable partner, voestalpine Eurostahl opens the door for customers to the full range of voestalpine products and services. As the company s international sales organisation, voestalpine Eurostahl is the direct link between customers and the producing companies. Sales and distribution subsidiaries and representatives in twenty countries speak the voestalpine language and guarantee hassle-free, one-stop customer access to competent support and solutions. All foreign offices and contact partners will be found at 27

28 voestalpine Grobblech GmbH voestalpine-straße Linz, Austria T. +43/50304/ F. +43/50304/ grobblech@voestalpine.com May 2008 Edition