GMAW-STT process
The GMAW-STT process
- An advanced welding process Ing. Fred Neessen, EWE, Lincoln Smitweld B.V., The Netherlands Ferry Naber, EWT, Lincoln Electric Europe B.V.
Abstract Inverter based technology combined with modern Arc Wave Form Control ™ created the base for the new GMAW process, the so-called STT ® process. Details of this process are described. Increased productivity, high weld metal quality, almost no spattering and low fume emission are the main features which led to attractive applications. They include, in particular, one side root pipe welding and sheet metal welding such as applied in cladding of reactor vessels of flue gas desulphurisation components of power plants. Details of the welding procedures and the verification of the quality aspects are reported.
Introduction The welding of the root layer in pipe girth welds and butt welds in sheet material, determines the quality and economy of the operation in many applications. Assuming optimal welding consumables, it is correct to say that weld quality depends on the welder's control of the arc and heat supply as well as the effects of dilution of the parent material. The economy of the welding operation is strongly influenced by the time of completion of the welds. Particularly for pipe welds, further economic benefits are obtained when the root is immediately ready for the high efficiency fill procedures. In conventional pipe welding in (petro) chemical industry and oil & gas piping systems GTAW is a common method. The process is time consuming and the corrosion properties of the weldments do not always comply with the requirements. In sheet welding GMAW or SMAW may be applied. These processes may cause problems in terms of dilution and spattering. A modification of the GMAW, the Surface Tension Transfer ™ (STT ®), has been invented and launched recently (1). The process applications are diverse. Pipe welding in many material grades has been developed as the major application in Europe. But the process is extremely attractive for sheet welding as well. Sheet cladding, or wall papering, of large internal reactor surfaces is another productive method successfully applied in electric power plant absorbers in the USA (2). In this paper, the new welding process is introduced. Furthermore, a number of applications of the new process with the associated approval testing are described.
Lincoln Smitweld B.V.,Nijmegen, The Netherlands, October 2003
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GMAW-STT process
GMAW-STT In the surface tension transfer mode the arc current is electronically controlled to meet the instantaneous requirements of the arc during the entire process. STT uses a new generation of inverterbased power sources without a constant current (CC) or constant voltage (CV) setting. In the conventional GMAW short arc mode high currents occur at the moment of pinching of the fused droplet. The Figure 1. Conventional GMAW / CO2 welding frequent exploding of the fuse generates a high level of spatter (Figure 1). Reducing the current causes arc instability due to the relative long time of arc shorting. These two factors oppose producing both a stable arc and low spatter in the regular short arc mode. The STT results in a low spatter level (Figure 2.). The approach is different in several ways from the short arc proFigure 2. GMAW-STT fillet welding cess. From the front of the machine (Figure 3.) the welder controls the wire feed speed and independently the background and peak currents. In addition a hot start and a switch for high heat conductivity materials and stainless steel respectively is available. In the most recently marketed STT equipment (STT II), the tail of the slope from peak to back current can be influenced to provide more energy when required.
Figure 3. The Invertec STT II power source
Figure 4 illustrates the arc behaviour and the related current / voltage level in repeating cycles. The current at the initial short is reduced immediately. The low-level current is maintained for a short period of time so that the surface tension forces can begin to transfer the droplet to
Lincoln Smitweld B.V.,Nijmegen, The Netherlands, October 2003
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GMAW-STT process
the puddle. A high level of pinch current is then applied to speed up the transfer of the fused drop. The "necking down" or squeezing of the shorted electrode is monitored. When a specific value is reached, the pinch current is quickly reduced to a low value before the fuse separates. When the short breaks, it does so at a low current, producing very little spatter. Following this, the arc is re-established and a high current (peak current) is applied. The formed plasma is boosted (Plasma Boost) and the momentary pulse of current causes the arc to broaden, melting a wide surface area. This action eliminates cold lapping and promotes good fusion. The time of maintaining high currents is short enough to prevent boiling of the metal at the wire electrode tip which limits the fume emission substantially in comparison with open arc GMAW. The STT process produces a relatively high level of pinch current for arc stability while reducing spatter through precise current control. During the plasma boost the current is at a high level, melting the electrode and the work piece. This boost (up to 450A) greatly influences the deposit rate. This high current arc period cause a pressure in the arc, which pushes down the surface of the weld puddle. A controlled reduction of the current to the level of the “background current” reduces puddle agitation and premature shorting, consequently providing a smoother Figure 4. Wire electrode current and voltage wave weld bead appearance. forms for a typical STT welding cycle The minimum background current is required to maintain the fluidity of the molten droplet and, by compensating for the loss of energy through the base material, provide for proper fusion into the side-walls of the joint. Together with the peak current it eliminates cold lapping, an essential difference from the GMAW process in the short arc mode. As with most welding processes STT uses an open joint gap except for thin sheet and pipe wall thickness. This assures the supply of filler material, which is, for example, required in duplex stainless steel. Simple measures are available to keep sufficient backing gas when one side pipe welding is executed. A comparison of available welding processes with the objective to reach optimal heat control and dilution as well as an almost complete reduction of spattering indicates a number of attractive arguments for the application of GMAW-STT welding. Other advantages such as low fume emission, in comparison with regular GMAW, and an improved weld metal microstructure with consequently better corrosion properties are important arguments in the welding process selection.
Pipe welding applications Girth welds in pipes with a wide variety (Figure 5) of most representative material grades have been tested for root weld properties by customers, institutes and our laboratories. High alloyed pipe materials were available in sizes ø 100 600 mm (4" - 24") with the wall thickness ranging between 2 - 20 mm. In the high strength transport pipe steel API 5L Grade X80, a common size of OD 40" having Lincoln Smitweld B.V.,Nijmegen, The Netherlands, October 2003
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GMAW-STT process
a wall thickness of 14.7 mm was tested. Welding was executed with the power source INVERTEC STT, in combination with the wire feeder LN 742. The gun was positioned at ~2h (pos. PG or 3Gdown) when welding a rotating pipe. With the pipe in a fixed position welding was done in all positions (pos. PG or 5/6Gdown). Typical welding procedures records include the completion of the weld either in one pass (up to 3.5 mm wall thickness) or in multi-layers, using processes such as SMAW, FCAW or SAW for the fill passes. Appendices 1 shows a welding procedure qualification record reported for welding duplex stainless pipe material in a rotating pipe set-up with efficient SAW for the fill and cap layers.
Figure 5. Pipe materials tested on GMAW-STT root welding WPQ
Base material
Material
Size
UNS
Welding
Number Number Ø [mm] t [mm] consumable
Shielding
Backing Ref. gas
LM
EN 10208: L355
114
3.6
LNM 26
Ar + 20% CO2
None
4
TWI
API 5L: X80
1016
14.8
LA 90
Ar + 20% CO2
None
5
168
11
LNM 12
Ar + 15% CO2
None
6
100
3
LNM 316LSi
Ar + 2% CO2
Ar
7
LNM 4462
Ar + 2% CO2
Ar
8
LPD710 DIN 17175: 15Mo3 DO90 STT08 (DM32) STT13
AISI 316L
1.4430
22% Cr DSS
1.4462
S31803
250
15
1.4501
S32760
280
22
LNM Zeron 100X Ar + 2% CO2
Ar
9
1.4547
S31254
215
3.5
LNM NiCro 60/20
Ar + 28% He + 2% CO2
Ar
10
15
LNM Zeron 100X Ar + 2% CO2
Ar
11
25% Cr SDSS
(DM78) (Zeron 100X) STT14 STT20
Alloy 254 (6% Mo) Super Austenitic X80 11Cr Super Martensitic
Welding practices / observations The welding parameter settings include background current, peak current and wire feed speed. Appropriate welding consumables were selected for the various base materials. The wire diameter varied between 0.8 to 1.2 mm with the size ø1.0 mm preferred for most applications, including vertical down welding of pipes with a wall thickness of 2-6 mm. It is important to note that the bevel preparation is just a V-joint with an open gap (except with wall thickness <3 mm). Simple methods to avoid excessive loss of the protective backing gas from the internal pipe area are needed. The use of Al-adhesive tape is effective due to the fact that the weld and HAZ internal surfaces are not as hot as with GTAW. Also the positioning of the welder and the gun require careful attention. It is essential that the arc is always directed perpendicular to the weld pool surface. Shielding gases influence the welding characteristics substantially. The mixed gases Ar + 2%CO2 and Ar + 28-38He + 2%CO2 perform well in most materials. When applying Ni-base filler material to fully austenitic material the Ar gas mixture with 28%He and 2% H2 proved to be very suitable due to better wetting resulting from its hotter arc and the cleaning action of the hydrogen. (This shielding gas cannot be used in duplex and super duplex material!) In most cases a stable arc setting can easily be found. Arc and weld pool control is surprisingly easy. Fusion to the pipe wall is virtually assured with a correct background current setting. The start / stop soundness is provided with smooth taper end grinding of just the run-on and run-off part of the weld end. The power source is equipped with a hot start facility, which increases the background current Lincoln Smitweld B.V.,Nijmegen, The Netherlands, October 2003
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GMAW-STT process
10% for 1-7 seconds. This hot start ensures proper fusion of the weld start. With the correct setting very attractive welds are made. The profile at both face and back are smooth. The weld thickness is such that the weld is complete in wall thickness up to 3.5 mm. In heavier pipes the root run has a thickness of 4-5 mm which allows further completion with any suitable welding process including SAW. The heat input of the root welding cannot be determined by classic calculations, using the current and voltage and welding speed. For the GMAW STT process an electronic integrator has been designed which allows the welding engineer to read the supplied energy over the period of arc time. Typically values of 1300-1800 J/s (or W) are measured in root welds in heavy pipes. For the duplex stainless steel fixed pipe qualifications welding speeds of 1,5-3,5 mm/s have been used. The heat input (HI) range is rather stable in the range of 0,5-0,8 kJ/mm. This is significantly lower than possible with the GTAW process. For that process the HI-level is typically 0.8-2.0 kJ/mm. The efficiency of this welding process is very attractive. Deposit rates are consistently on the level of 1.0-1.2 kg/h for ø1.0 mm and 1.3-2.2 kg/h for ø1.2 mm wire. This compares with 0.4-0.8 kg/h with GTAW under similar conditions. This higher deposit rate is evidenced by the higher welding speed (GTAW-STT: 90-160 mm/min; GTAW 30-40 mm/min) and root weld thickness. A consequence of the efficient use of energy is lesser overheating of the weld pool and droplet surface. Metal vaporisation is directly dependent on this surface temperature. Compared to GMAW short arc a significantly lower fume emission (approx. 50%) has been measured.
Testing The quality of the test welds has been verified with the appropriate methods. The following paragraphs give a summary of the various test programmes. Visual inspection of all welds showed a smooth wetting action at the back with a regular appearance and positive penetration without undercutting. Figure 6 to 8 shows a collection of pictures of the various root welds. In addition to the root appearance, other quality aspects such as root bend capability and macro-structures are shown. Where Ar backing gas is applied to prevent oxidation, it has been noted that under most circumstances a brighter back weld bead has been obtained, when compared to GTAW welds. It is obvious that the open weld gap requires a sufficient backing gas supply (15-25 l/min) after the normal purging of the internally exposed pipe volume. Root welds provide sufficient contrast on X-rays to reveal cracking, undercutting, suck back effects and porosity. Also spattering on the side of the weld, if present, is easily visible. GMAW-STT, executed under correct parameter setting and manipulation of the gun were defect free. Only an incorrect preparation of the start / stops and a setting of a too low background current may cause rejection due to pinholes or lack of fusion respectively. Root bend testing has been used to verify the correct fusion to the base material. The bend tests in sound X-ray tested welds confirmed the positive results. Figure 6 shows the result of (root) bend testing.
Lincoln Smitweld B.V.,Nijmegen, The Netherlands, October 2003
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GMAW-STT process
Figure 6. GMAW-STT weld in pipe X2CrNiMoN 22-5-3
a) b)
Macro section
c)
Bend specimen
Root appearance
Figure 7. GMAW-STT root weld in X2CrNiMoCuWN 25-7-3 (Zeron 100)
a)
b)
Macro section
c)
Root appearance
Micro-structure root
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GMAW-STT process
Figure 8. One side Super martensitic Cr-steel welding
Macro section Pittting corrosion testing according ASTM G48A, with the Na-EDTA modified solution (11) to stabilise the FeCl3-solution at the higher temperatures, ranks in particular the duplex and super-duplex weldments in their resistance to pitting corrosion (the critical pitting temperature -CPT- temperature) in Cl- containing media like process liquids and seawater cooling systems related to oil & gas production equipment and transport pipe lines. The test reacts severely on unwished transformation products, such as sigma phase and secondary austenite in the weld metal structure. Regular CPT-requirements for 22%Cr-duplex stainless weld metal are +23 ºC (12) and for 25%Cr-superduplex weldments +35ºC (13). With regular GTAW weldments these requirements are considered severe. In 6%Mo-alloyed stainless steel Alloy 254 the requirement of 40 ºC is not critical as long as the base material HAZ is not deteriorated. Figure 9 shows the results obtained in GMAW-STT test welding qualifications. The test results have been verified and confirmed on subsequent welds. Without exceptions GMAW-STT weldments, even with a multi-layer SMAW or SAW fill; pass the ASTM G48A pitting corrosion criteria with exceptional margins. The apparent sound structure of the root weld seems to be the determining factor. Figure 6 shows internal root run appearance and the associated structure (macro and microstructure) of a root run in super-duplex stainless steel Zeron 100 with 25 9 4 NL (LNM Zeron 100X) weld metal. Microstructure of GMAW-STT weld metal can be characterised as clean (no inclusions) with a sound solidification structure. Slag inclusions and undesired transformation products are almost non-existent (Figure 7c). Hardness measurements obtained with the GMAW-STT welding process with its low heat input verify the advantage of the process when applied to the referred high strength, low alloyed and duplex / super-duplex materials have been verified in the root area. Figure 10 lists the measured hardness in base material / HAZ and root weld metal. No critical hardness levels have been observed in the reported test welds. Lincoln Smitweld B.V.,Nijmegen, The Netherlands, October 2003
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GMAW-STT process
Chemical composition determination of the root weld metal is particularly relevant for weldments in regular X2 CrNiMo 17-10-2 as well as in duplex and super-duplex stainless steel. Figure 11 shows the composition of the pipe, the filler material and the root weld metal. The weld metal is found to be on the level expected, taking the dilution with the base material into account. In particular no loss of N is observed. This may explain the very good corrosion properties of these duplex and super-duplex weldments. The ferrite number FN, in addition, has been determined with the Fisher Ferritscope, calibrated with IIW secondary standards.
Figure 9. ASTM G48A Pitting corrosion test results WPQ
Base material
Weldmetal
according EN
EN 1600
Test temp.
Results
[°C] 23 No pitting
24 STT 08
X2CrNiMoN 22-5-3
G 22 9 3 N L
26 No pitting in weld;
30
Pitting in base metal and HAZ
35 37.5 STT 13
X2CrNiMoCuWN 25-7-4
G 25 9 4 N L
No pitting
40 42.5 45
Pitting in HAZ
35 STT 14
X1CrNiMoCuN 20-18-7
G NiCr21Mo9Nb
40
No pitting
45 50
Figure 10. Hardness in butt welds WPQ
Weldmetal
Base material
Trade name
EN class.
Harness HV10
Welding position
BM
HAZ
Weld
LM
L355
LNM 26
G 3 Si
2G
129 - 144
124 - 138
183 - 185
TWI
API 5L: X80
LA 90
G 4 Mo
3G
225 - 235
210 - 232
230 - 240
LPD710
15Mo3
LNM 12
G 2 Mo
1G
155 - 158
193 - 210
192 - 199
STT08
22% Cr DSS
LNM 4462
G 22 9 3 N L
1G
236 - 248
264 - 288
260 - 278
STT13
25% Cr SDSS
LNM Zeron 100X
G 25 9 4 N L
1G
241 - 243
248 - 264
257 - 258
STT20
X80 11Cr SMSS
LNM Zeron 100X
G 25 9 4 N L
1G
224 - 254
258 - 281
292 - 314
Lincoln Smitweld B.V.,Nijmegen, The Netherlands, October 2003
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GMAW-STT process
Figure 11. Chemical composition and Ferrite in GMAW-STT weld metal WPQ
DO 90
STT08
STT13
STT14
STT20
Base material
X2CrNiMo CuWN 25-7-4
X1CrNiMo CuN 20-17-6
X80 11Cr SMSS
Ferrite
Position
C
Cr
Ni
Mo
Cu
W
N
FN
~%
Pipe
0.025
17.2
10.6
2.1
0.22
-
0.04
0
0 -
X2CrNiMo 17LNM 316LSi 11-2
X2CrNiMoN 22-5-3
Chemical composition
Welding consumable
LNM 4462
LNM Zeron 100X
LNM NiCro 60/20
LNM Zeron 100X
Wire
0.014
18.2
11.6
2.7
0.11
-
0.04
-
Weld
0.023
18.0
11.2
2.5
0.17
-
0.04
7.6
7
Pipe
0.025
22.2
5.2
3.1
0.25
-
0.18
60
43
Wire
0.015
22.9
8.7
3.3
0.12
-
0.15
-
-
Weld
0.023
22.6
7.9
3.2
0.17
-
0.17
70
59
Pipe
0.029
25.1
6.5
3.8
0.63
0.70
0.24
65
48
Wire
0.016
25.2
9.2
3.7
0.64
0.58
0.23
-
-
Weld
0.028
24.8
8.5
3.9
0.62
0.60
0.22
55
40
Pipe
0.019
19.7
16.9
6.0
0.61
0.1
0.17
0
0 -
Wire
0.012
21.5
65.2
8.8
0.01
-
0.03
-
Weld
0.010
21.4
55.8
9.0
-
-
0.08
0
0
Pipe
0.015
10.7
1.7
0.05
0.5
-
0.01
-
-
Wire
0.018
25.1
9.5
3.75
0.77
0.66
0.23
-
-
Weld
0.017
23.5
8.2
3.3
0.62
0.49
0.14
49
36
Sheet welding Sheet cladding with stainless or Ni-base alloys of large surfaces is a well-known technique. The sheets are cut in sizes ranging in surface between 6 to 360 dm2. The sheet follows the curve of the wall of the vessel is welded locally (plug or slot welds) and at the sheet edges to the low alloyed pressure vessel steel. Plate thickness varies between 1.5 and 3 mm. A common problem is to avoid excessive dilution of the base material and overheating of the sheet. Deep arc penetration and too much heat input with an unbalanced heat flow are known to destroy the quality of the weld and HAZ and can cause uncontrollable sheet distortion or warpage. It is essential that the welds be without any porosity or lack of fusion. Otherwise, the corrosive medium attacks the vessel behind its protective clad. In addition, spattering associated with the conventional GMAW process causes time consuming cleaning including not wished grinding. Studies for projects, such as the Ni –alloy cladding of the TVA Plant in Cumberland, Tennessee (2) and the AISI 304L sheet cladding of a crystaliser reactor vessels (3) showed the attractive characteristics of the STT process for these applications. In the power plant absorber, a component of a flue gas desulphurisation (FGD) system of the TVA plant, the wall with numerous inlets (nozzles) needs to be protected against the aggressive moistened SO2, which forms H2SO4 in the flue gas atmosphere. The material selection depended upon the particular area in the absorber. Nickel alloys such as NiCr21Mo14W (Alloy C22) and NiMo16CrW (Alloy C276) were selected for the most corrosive areas. Welding has been executed with an AWS A 5.14 ER NiCrMo-4 filler wire. The sheet edge welds to the base material (Figure 12) and the overlap weld (Figure 13) in the Ni-alloys itself were welded with single runs which, thanks to the excellent heat control of the STT process, exhibited preferred quality (no defects, superior structure) and no distortion. The fabricator, Williams Union Boiler, documented substantial labour savings due to the increased travel speeds, decreased repair time and lesser clean-up work. Lincoln Smitweld B.V.,Nijmegen, The Netherlands, October 2003
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GMAW-STT process
Figure 12. Fillet weld on site of Nickel-alloy sheet material to substrate
Conclusions The GMAW-STT process proves to be attractive for welding the root pass in pipes with dimensions from OD > 100mm and wall thickness of > 2mm. The unique process characteristics provide advantages over the other suitable process considered. When compared with GMAW in short arc mode the advantages are: • almost no spattering • sound sidewall wetting and no lack of fusion • low fume emission In comparison with GTAW for pipe welding of all stainless steel grades, the following major advantages can be mentioned: • low heat input, providing a preferred microstructure (in particular in duplex and super- duplex stainless steel) with improved corrosion resistance • no loss of major alloying elements, including nitrogen, has been found • substantially increased productivity Sheet cladding (wallpapering) proves to be another successful application of the GMAW-STT process. Low dilution of the base metal, a key for good weld metal quality, and the avoidance of spattering together with the increased productivity provide unique benefits. The process can be learned quickly by experienced welders without any difficulty. In the relatively short period of time since its introduction at the Schweissen und Schneiden exhibition (Sept. 1993) the Lincoln GMAW-STT process has already successfully been applied in many important projects in industries such as oil & gas installations, chemical plants, power generation and automotive constructions all over the world. Lincoln Smitweld B.V.,Nijmegen, The Netherlands, October 2003 10
GMAW-STT process
Acknowledgement The publication has been made possible by the kind permission of the referred companies. Invaluable contributions have been received from colleagues, at Lincoln Smitweld at the Lincoln Electric Company.
Figure 13. Lap weld in alloy C22 with wire type ERNiCrMo-4, diameter 1.2 mm
References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.
E. K. Stava: A new, low spatter arc welding machine, The Fabricator (1994), Vol. 24, No. 2 D. Dodson: New welding process improves quality and speed for nickel wallpapering of electric power plant absorbers, to be published Company Esscher, The Hague, The Netherlands, private communication Lincoln Smitweld Reportage (1995), No.2, Lasunie Made verlaagt laskosten door STT The Welding Institute: tests under supervision of TWI, 1996 Schelde MT Consulting: STT lassen, rapportage van bevindingen, rep.no. 95.015/LDP710, 1995 Lincoln Smitweld: WPR DO 90, 1995 Lincoln Smitweld: WPR STT 08, 1995 Lincoln Smitweld: WPR STT 13, 1996 Lincoln Smitweld: WPR STT 14, 1996 NAM Groningen Long Term Project, private communications (STT20) International Institute of Welding, doc. II-1270-95 Clyde Petroleum, Spec. 9253/0000/S/L/0002 Statoil Spec. R-SF-360, rev. 0 L. van Nassau, The GMAW-STT process. An advanced welding process for root pipe and sheet welding. Doc. LSW 0165
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GMAW-STT process
Welding Procedure Approval Record Procedure Specification Base material Welding processes Manual or machine
WPAR : Rev. :
Appendix 1 Page 1 / 4 P 2000.06 0
Ref. WPQ :
Test Results
X 80 - 11Cr (Fabrique De Fer) 66151 A: GMAW-STT B: SAW Manual and machine
Radiographic-ultrasonic Examination:
N.D
All-weld-metal tension test ø 6 mm Rp0.2 / Rp1.0 Yield point [Mpa] : 696 / 754 PA (1G) Tensile strength [Mpa] : Rm Welding position 869 Filler metal (trade) 1:LNM Zeron 100X 2:LNS Zeron 100X Elongation, A5 [%] : 26 P 2000 EN 760: A AF 2 63 DC Flux Reduction, Z [%] : 56 Test temp. [°C]: see table Impact tests Filler metal classific. EN 12072: G/S 25 9 4 N L ISO-V [Joule] Size of specimen: 10 x 10 x 55 mm Flow [l/min] - 20°C - 30°C 15 Shielding gas [l/min] 98 Ar + 2% CO2 av. av. 89 81 Backing (gas) [l/min] Argon 4.0 STT: 10 Clw 88 88 90 89 78 75 97 49 Gouge method N.A. SAW: 10 Fl 89 118 85 35 72 40 178 78 Fl + 2 180 198 155 40 120 75 Current / polarity DC + Preheat temp. [°C] RT Interpass temp. [°C] max. 130 Chemical composition Postheat treatment N.A. Welder's name Dirk Ritsema Tiny Bouwmans C Mn Si P S Cr Ni Mo Cu N O 0.015 1.60 0.18 0.022 0.001 10.65 1.65 0.05 0.45 0.01 Laboratory Test No. Base Remarks : LNM Zeron 100X Batch Weld LNS Zeron 100X Batch 1627343 P 2000 Batch F 7037
Welding Procedure Pass Consumable Welding Current No. index Ø [mm] Ampere Volts 1
A1
BC: 80 PC:275 Stick-out for SAW is 20mm 2 B2 2.4 275 3 B2 2.4 360 4 B2 2.4 400 5 B2 2.4 375
Joint Detail
1.0
CTOD testing Speed H.I. Notch Temp. [mm/min] [kJ/mm] location [°C]
CTOD value [mm]
Fracture mode
(0.6 - 0.8) 14 - 16 120 (WFS = 485 cm/min)
28 28 29 28
500 500 500 500
0.92 1.21 1.39 1.26
Ferrite Content (FN) weld metal Magne Gage Filling layers
Root
Hardness see sketch Test type : Vickers and HRc Load:10 kg BM HAZ WM Face Mid Root Weld 1 2 3 4 HRc Sketch
HAZ
BM
5
We hereby, certify that the statements in this record are correct. Project NAM, Groninger Long Term Manufacturer or Contractor Lincoln Smitweld bv Authorized by Leo van Nassau Issued by Fred Neessen Date 22 January 1998
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