Flux Cored Wires for LNG Applications

Transcription

1 Metrode Welding Consumables Flux Cored Wires for LNG Applications Zhuyao Zhang, Mark Golding and Pierre Gerard 9 October 2013

2 Content Controlled ferrite flux cored wires for low carbon austenitic stainless steel piping systems 625 type nickel base flux cored wire for 9%Ni steel storage tanks

3 Content Main base alloys for LNG facilities Advantages of flux cored wire welding Flux cored wires for stainless steels Microstructure control δ ferrite Mechanical properties Flux cored wire for 9%Ni steel Choice of filler alloy NiCrMo-3 type nick base Mechanical properties Summary

4 Why LNG? Natural gas is mainly methane LNG is produced by cooling natural gas to -161 C at atmospheric pressure Remains liquid by autorefrigeration (cryogen) Liquefaction reduces volume by a factor of 600

5 Why LNG? Rapid increase in natural gas consumption: world consumption and forecast Ref: Energy Insightes

6 Why LNG? Cost of natural gas transportation LNG vs gas through pipelines Ref: Institute of Gas Technology

7 LNG transpiration and storage LNG transportation

8 LNG transpiration and storage Storage tank SS pipe work

9 Base alloys for LNG Main base alloys for LNG facilities

10 Base alloys for LNG Temp. C Base Alloys -50 CMn -60 CMn (+Ni) -75 3%Ni /5%Ni %Ni L L L/316L

11 Base alloys and consumables for LNG Temp. C Base Alloys Consumable -50 CMn -60 CMn (+Ni) Low alloy -75 3%Ni /5%Ni %Ni Ni-base L Control ferrite L L/316L Non-ferrite

12 Welding processes for site-construction Conventionally: GTAW + SMAW or GTAW + SAW in the case of LNG tank 2G joint

13 Base alloys and consumables for LNG Temp. C Alloy Consumable Solid Wire SMAW SAW -50 CMn 1Ni E8018-C3 (Tufmet 1Ni.B) CMn (+Ni) Low alloy 2Ni E8018-C1 (Tufmet 2Ni.B) %Ni 2Ni E8018-C2 (Tufmet 3Ni.B) /5%Ni Ni-base 82 ENiCrFe-3 (Nimrod 182KS) %Ni 625 or C276 ENiCrMo-6 (Nyloid 2) C276 or 625 wire + flux L ER308L(CF) Control ferrite L ER316L(CF) E308L-16 Ultramet 308LCF E Ultramet 316LCF E308L-15 Ultramet B308LCF E316L-15 Ultramet B316LCF L/316L Non-ferrite ER316MnNF (nil ferrite) E316L-16 (nil ferrite) E316L-16 (nil ferrite) --

14 Welding processes for site-construction Conventionally: GTAW + SMAW or GTAW + SAW in the case of LNG tank 2G joint Why flux cored wire?

15 Welding processes for site-construction Conventionally: GTAW + SMAW or GTAW + SAW in the case of LNG tank 2G joint Why flux cored wire? High productivity

16 Base alloys for LNG 10 8 FCAW (1.2mm) GMAW (1.2mm) SMAW Deposition Rate, kg/h Welding Current, A

17 Welding processes for site-construction Conventionally: GTAW + SMAW or GTAW + SAW in the case of LNG tank 2G joint Why flux cored wire? High productivity Possibility for fully automated welding

18 Automated welding mock up: 9%Ni steel + ENiCrMo-3 FCW

19 Welding processes for site-construction Conventionally: GTAW + SMAW or GTAW + SAW in the case of LNG tank 2G joint Why flux cored wire? High productivity Possibility for fully automated welding Good weld cosmetic profile particularly when involves nickel base filler

20 Welding 9%Ni steel with nickel base filler metal FCAW (3G) SMAW (3G) 9%Ni steel 9%Ni steel Ni base FCW Ni base SMAW

21 Welding processes for site-construction Conventionally: GTAW + SMAW or GTAW + SAW in the case of LNG tank 2G joint Why flux cored wire? High productivity Possibility for fully automated welding Good weld cosmetic profile particularly when involves nickel base filler Good weld metal integrity Excellent mechanical properties, particular low temperature impact toughness

22 Base alloys and consumables for LNG Temp. C Alloy Consumable Solid Wire SMAW FCAW -50 CMn 1Ni E8018-C3 (Tufmet 1Ni.B) E71T1-21 Metcore DWA55E -60 CMn (+Ni) Low alloy 2Ni E8018-C1 (Tufmet 2Ni.B) %Ni 2Ni E8018-C2 (Tufmet 3Ni.B) /5%Ni 82 ENiCrFe-3 (Nimrod 182KS) -- Ni-base ENiCrMo3T %Ni 625 or C276 ENiCrMo-6 (Nyloid 2) Supercore 625P L ER308L(CF) Control ferrite L ER316L(CF) E308L-16 Ultramet 308LCF E Ultramet 316LCF E308L-15 Ultramet B308LCF E316L-15 Ultramet B316LCF E308LT1-4 Supercore 308LCF E316LT1-4 Supercore 316LCF L/316L Non-ferrite ER316MnNF (nil ferrite) E316L-16 (nil ferrite) E316L-16 (nil ferrite) E316L-T1-4 Supercore 316NF

23 Base alloys and consumables for LNG Temp. C Alloy Consumable Solid Wire SMAW FCAW -50 CMn 1Ni E8018-C3 (Tufmet 1Ni.B) E71T1-21 Metcore DWA55E -60 CMn (+Ni) Low alloy 2Ni E8018-C1 (Tufmet 2Ni.B) %Ni 2Ni E8018-C2 (Tufmet 3Ni.B) /5%Ni 82 ENiCrFe-3 (Nimrod 182KS) -- Ni-base ENiCrMo3T %Ni 625 or C276 ENiCrMo-6 (Nyloid 2) Supercore 625P L ER308L(CF) Control ferrite L ER316L(CF) E308L-16 Ultramet 308LCF E Ultramet 316LCF E308L-15 Ultramet B308LCF E316L-15 Ultramet B316LCF E308LT1-4 Supercore 308LCF E316LT1-4 Supercore 316LCF L/316L Non-ferrite ER316MnNF (nil ferrite) E316L-16 (nil ferrite) E316L-16 (nil ferrite) E316L-T1-4 Supercore 316NF

24 Controlled ferrite FCW Controlled ferrite flux cored wires for low carbon austenitic stainless steel piping systems

25 Stainless in a LNG facility Typically 304L and 316L types Base materials have excellent cryogenic toughness Pressure equipment Pipe to connect plant and also connect plant to jetty

26 Stainless in a LNG facility Property requirements: Toughness For simplicity cryogenic Charpy tests are normally carried out at -196 C, liquid nitrogen temperature A common requirement is 0.38mm lateral expansion (ASME B31.3) Some European projects (TÜV) do have a minimum Charpy energy requirement, for example 40J/cm 2

27 Lateral Expansion, mm Stainless in a LNG facility LE=0.38mm Impact Energy, J

28 Stainless in a LNG facility Weld metal toughness Base materials are carefully processed. Weld metals are as-cast and do not necessarily achieve the required toughness. How to achieve weld metal impact properties? Solution annealing Fully austenitic consumables Gas shielded processes Specially designed Controlled Ferrite consumables

29 Stainless in a LNG facility Flux cored wires specially designed with controlled ferrite CF Design philosophy Control ferrite Control alloy content Flux system

30 Controlled ferrite FCWs for stainless steel in a LNG facility Ferrite control

31 Lateral Expansion, mm Ferrite control Ferrite & LE 308L weld Ferrite, FN 308L

32 Lateral Expansion, mm Ferrite control Ferrite & LE 308L & 316L welds Ferrite, FN 308L 316L

33 Lateral Expansion, mm Ferrite control Ferrite & LE 308L & 316L welds 308L 316L LE=0.38mm <5FN Ferrite, FN

34 Ferrite control Various standards have ferrite limits for stainless steels, for example: ASME III requires 5FN minimum; 3-10FN for service above 427 C. API 582 has 3FN minimum, it is noted that for cryogenic service lower FN may be required.

35 Lateral Expansion, mm Ferrite control 308L & 316L welds: ferrite control range Ferrite, FN 308L 316L LE=0.38mm

36 Ferrite control composition of the weld metals 308L weld composition: rutile SMAW, basic SMAW, rutile FCW Type C Mn Si Cr Ni Mo N AWS/ASME spec range Ultramet 308LCF (E308L-16) < Ultramet B308LCF (E308L-15) Supercore 308LCF (E308LT1-4)

37 Ferrite control composition of the weld metals 308L weld composition: rutile SMAW, basic SMAW, rutile FCW Type C Mn Si Cr Ni Mo N FN AWS/ASME spec range Ultramet 308LCF (E308L-16) < Ultramet B308LCF (E308L-15) Supercore 308LCF (E308LT1-4)

38 Ferrite control composition of the weld metals 308L weld composition: rutile SMAW, basic SMAW, rutile FCW Type C Mn Si Cr Ni Mo N FN AWS/ASME spec range Ultramet 308LCF (E308L-16) < Ultramet B308LCF (E308L-15) < Supercore 308LCF (E308LT1-4)

39 Ferrite control composition of the weld metals 316L weld composition: rutile SMAW, basic SMAW, rutile FCW Type C Mn Si Cr Ni Mo N FN AWS/ASME spec range Ultramet 316LCF (E316L-16) < Ultramet B316LCF (E316L-15) < Supercore 316LCF (E316LT1-4)

40 Nieq = Ni+35x%C+20x%N+0.25x%Cu Ferrite control composition of the weld metals First solidifying phase: A A A+F First solidifying phase: -F F+A F Creq = %Cr+%Mo+0.7x%Nb

41 Ferrite control & Suutala diagram P+S=~0.03wt% 308LCF range 308LCF & 316LCF range

42 Ferrite control & weld microstructure Supercore 308LCF weld cap 5FN measured Predicted ferrite WRC = 4FN weld mid 4FN measured

43 Controlled ferrite FCWs for stainless steel in a LNG facility Alloy control

44 Lateral expansion, mm Alloy control 308L weld High alloy LE=0.38mm Ferrite, FN

45 Lateral expansion, mm Alloy control 308L weld Medium alloy High alloy LE=0.38mm Ferrite, FN

46 Lateral expansion, mm Alloy control 308L weld Low alloy Medium alloy High alloy LE=0.38mm Ferrite, FN

47 Alloy control Composition balanced to achieve the optimised ferrite level. More critical for 316L than 308L. For 316L FCW it means that Mo is in the range %. The controlled FCWs conforms to AWS 308L and 316L specifications; but the 316L type does not meet the EN ISO specification (EN ISP A) because it requires 2.5%Mo minimum.

48 Controlled ferrite FCWs for stainless steel in a LNG facility Flux system

49 Controlled ferrite FCWs for stainless steel in a LNG facility For all-positional welding, fast freezing rutile flux system is used for the wires. Designations;- E308LT1-1/4 (Supercore 308LCF) R316LT1-1/4 (Supercore 316LCF) Low N 2 helps achieving good toughness: FCW ~0.03% SMAW (-15) ~0.08% SMAW (-16) ~0.04% SAW ~0.06%

50 Controlled ferrite FCWs for stainless steel in a LNG facility Mechanical properties

51 Lateral Expansion, mm Controlled ferrite FCWs mechanical properties 0,9 0,8 0,7 0,6 0,5 LE=0.38mm 0,4 0,3 0,2 0, Impact Energy, J 308L LE vs Impact

52 Lateral Expansion, mm Controlled ferrite FCWs mechanical properties 0,9 0,8 0,7 0,6 0,5 LE=0.38mm 0,4 0,3 0,2 0,1 308L SC308LCF Impact Energy, J LE vs Impact C

53 Controlled ferrite FCWs mechanical properties LE=0.38mm LE vs Impact C

54 Controlled ferrite FCWs mechanical properties Procedural effects on FCAW toughness -196 C Welding position, shielding gas and heat input Gas Position Heat Input kj/mm Charpy energy J Lateral expansion mm Ar-20%CO 2 1G %CO 2 1G Ar-20%CO 2 3G Ar-20%CO 2 3G %CO 2 3G

55 Controlled ferrite FCWs mechanical properties Consumable Supercore 308LCF Supercore 316LCF Specification, AWS A5.22 E308LT1-4 E316LT1-4 Specification, EN ISO A T 19 9 L P M 2 -- Shielding gas Ar-20%CO 2 Ar-20%CO 2 Tensile strength, MPa % Proof stress, MPa Elongation, % 4d d Reduction of area, % Impact properties -196 C: impact energy, J lateral expansion, mm

56 Controlled ferrite FCWs mechanical properties Process FCAW SMAW FCAW SMAW Consumable Supercore 308LCF Ultramet 308LCF Supercore 316LCF Ultramet 316LCF Specification, AWS A5.22 E308LT1-4 E308L-16 E316LT1-4 E316L-16 Specification, EN ISO 17633/EN 1600 T 19 9 L P M 2 E 19 9 L R Shielding gas Ar-20%CO 2 -- Ar-20%CO 2 -- Tensile strength, MPa % Proof stress, MPa Elongation, % 4d d Reduction of area, % Impact properties -196 C: impact energy, J lateral expansion, mm

57 Controlled ferrite FCWs mechanical properties FCAW SMAW SAW FCAW SMAW SAW Supercore 308LCF Ultramet 308LCF ER308LCF Supercore 316LCF Ultramet 316LCF ER316LCF E308LT1-4 E308L-16 ER308L E316LT1-4 E316L-16 ER316L T 19 9 L P M 2 E 19 9 L R 3 2 S 19 9 L S L Ar-20%CO 2 -- LA491 Ar-20%CO 2 -- LA

58 Controlled ferrite FCWs for stainless steel in a LNG facility Project examples

59 Controlled ferrite FCWs for stainless steel in a LNG facility SAGE terminal - UK First use of CF consumables, early 1990 s. ExxonMobil/Ralph M Parsons. 6G fixed pipe. SMAW. GTAW.

60 Controlled ferrite FCWs for stainless steel in a LNG facility Isle of Grain, UK First use of the CF flux cored wire. 304L pipe. 10mm wall thickness. 915mm OD.

61 Controlled ferrite FCWs for stainless steel in a LNG facility Isle of Grain, UK STT root FCAW fill & cap

62 Controlled ferrite FCWs for stainless steel in a LNG facility Isle of Grain, UK: Project procedure data Contractor Project Material Root welding process and consumable. Filling process and consumable. P M Associates UK Ltd Grain-LNG importation facility, Isle of Grain, UK 304L 36in Schedule 10S Lincoln STT GMAW LNM 304Si FCAW Supercore 308LCF Transverse tensile strength, MPa 621, 621 Weld impact properties -196 C: 10x7.5mm - impact energy, J 32, 29, 34 (32) - lateral expansion, mm 0.81, 0.70, 0.73 (0.75) HAZ impact properties -196 C: 10x7.5mm - impact energy, J 107, 74, 70 (84) - lateral expansion, mm 1.44, 1.02, 1.04 (1.17)

63 Content Controlled ferrite flux cored wires for low carbon austenitic stainless steel piping systems 625 type nickel base flux cored wire for 9%Ni steel storage tanks

64 LNG Tank Construction Storage tank

65 LNG Tank Construction Steel vapor barrier 304L cryogenic piping work Suspended Aluminum deck Concrete pre-stressed outer shell 9%Nickel steel inner tank Insulation

66 LNG Tank Construction: 9%Ni steel Steel vapor barrier 304L cryogenic piping work Suspended Aluminum deck Concrete pre-stressed outer shell 9%Nickel steel inner tank Insulation

67 Background of 9% Nickel steel Two principle types of 9% Nickel steel used to build LNG storage tanks: Double normalized + Tempered (NN+T) - ASTM A353 / A353M Quenched & Tempered (Q+T) - ASTM A553 / A553M Both NN+T & Q+T steel have a martesitic microstructure containing Nickel rich ferrite and stable high carbon Austenite provides good strength and low temperature impact toughness

68 Background of 9% Nickel steel Yield Strength: >430 MPa UTS: MPa Elongation: >35 % C Impact (CVN): J Lateral Expansion: >0.38mm Shear Fraction: >80 % CTOD: >0.30mm

69 LNG tank construction: 9%Ni steel 9%Nickel steel inner tank construction A: 9%Ni Inner tank 2G joint: 625 SAW or HAS C276 SAW B: 9%Ni Inner tank 3G joint: ENiCrMo-6 SMAW ENiCrMo3T1-4 FCAW

70 Nickel base FCW for 9%Ni steel LNG AWS A5.34:2007: ENiCrMo3T1-4 ISO 12153:2011: T Ni 6625 P M 2 Type C Mn Si Cr Ni Mo Nb+Ta Ti Fe Cu AWS/ASME spec range min ISO spec range min SC625P: typical * Single values are maximums

71 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P General features All position rutile flux cored wire Designed for either M21 or 100%CO2 shielding gases Diameter 1.2mm Minimal spatter Very stable arc Self releasing slag * Single values are maximums

72 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Operating parameters Polarity: DC+ Gas flow: litre/min ESO: 15-20mm Parameters: G/3F: ~25-26V ~ A (6-8m/min) 1G/2F: Metal recovery: 90% ~28-29V ~ A (8-10m/min) Very similar to welding with all-positional stainless steel FCWs * Single values are maximums

73 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Operability Semi-auto: Root pass (60 V) Full-auto: Capping (60 V) * Single values are maximums

74 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Operating parameters Optimum range

75 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Deposition rate ~4.5kg/h ~2.5kg/h

76 Deposition rate kg/h Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Deposition rates comparison: FCAW vs. SMAW 2,5 2,3 2,1 2,25 1,9 2,03 1,7 1,5 1,65 1,68 1,3 1,1 0,9 1,09 1,15 0,7 0,5 2.5 low 75A 2.5 high 90 A 3.2 low 130A 3.2 high 145A 4.0 low 150A 4.0 high 180A 160% Metal recovery & 99%Ni core wire

77 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Deposition rates comparison: FCAW vs. SMAW ~4.5kg/h ~2.5kg/h MMA high: ~2.25kg/h MMA low: ~1.1kg/h

78 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P All weld metal properties Tensile at ambient temperature: Position Rp0.2, MPa Rm, MPa A4, % A5, % Z, % All-weld 1G All-weld 3G Toughness:

79 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P All weld metal properties Tensile at ambient temperature: Position Rp0.2, MPa Rm, MPa A4, % A5, % Z, % All-weld 1G All-weld 3G AWS - - >690 > EN SIO - >420 >690 - >22-9%Ni steel weld typical: - > > Toughness:

80 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P All weld metal properties Toughness: Position RT J -100 C J -196 C J LE at -196 C mm All-weld PF/3G All-weld PF/3G %Ni steel weld metal typical requirement >0.38 Toughness:

81 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Hot cracking susceptibility test: T-joint test Test set-up (JIS Z ): Weld 2: Test weld 40 Weld 1: Restraining weld

82 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Hot cracking susceptibility test: T-joint test Test welds:

83 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Hot cracking susceptibility test: T-joint test Test welds: layer by layer dye penetration assessment Test weld Restraining weld Cross section of test weld (height=~5mm)

84 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Hot cracking susceptibility test: T-joint test Test welds: layer by layer dye penetration assessment Test Weld (top surface) Cross section of test weld (height=~5mm)

85 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Test Weld: (1.0mm below top surface) Test Weld: (2.5mm below top surface)

86 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Procedure test: 9%Ni 3G joints 1 3 Root on ceramic 2 Root on round ceramic Root on ceramic + seal weld

87 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Procedure test: joint 3 Weld metal microstructure Joint macro image Weld cap

88 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Procedure test: joint impact C Joint CLW CLW* HAZ HAZ* BM BM* (2/3) n.a. 165 n.a. - n.a. 74 (1/3) n.a. 136 n.a. - n.a. 71 (root) n.a. 96 n.a. - n.a. * 7,5mm sub size CVN values converted to full size values

89 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Procedure test: joint impact C Weld HAZ 79J 165J 71J 96J 74J 136J

90 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Procedure test: tensile properties AWS type and 9%Ni steel joints tensile properties Joint Position Rp0.2, MPa Rm, MPa A4, % A5, % Z, % AWS type coupon 1G AWS type coupon 3G %Ni joint All-weld 3G (2/3 thickness) %Ni X-weld tensile 3G (2/3 thickness) 3G (2/3 thickness) %Ni steel weld typical > >35

91 Nickel base FCW for 9%Ni steel LNG SUPERCORE 625P Procedure test: bend test side and transverse Face (transverse) Root (transvers)

92 FCWs for LNG applications All-positional flux cored wires are now available for applications of LNG facility constructions; FCW for 304L and 316L grade stainless steels are controlled ferrite 308L and 316L types; FCW for LNG storage tank 9%Ni steel is 625 type which enables full automated 3G welding; These flux cored wires demonstrated very good weldability; satisfactory strength; excellent cryogenic (-196 C) toughness. The impact properties are compatible and in most cases better than equivalent SMAW electrode welds; Benefiting from its nature of continuous welding and capability of fully automated welding, FCW process offers considerable advantages in producing weld joints with sound microstructure quality and low rate in defects; Applications of FCWs in the LNG construction offer significant productivity benefit, hence provide potential to substantially reduce the project cost. Summary

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