Effect on microstructure and properties of super duplex stainless steel welds when using backing gas containing nitrogen and hydrogen

Westin, Elin M.; Johansson, Mikael; Bylund, L.-Å.; Pettersson, Rachel

doi:10.1007/s40194-014-0120-4

Cited by 25 publications

(7 citation statements)

References 13 publications

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“…Review of other studies (Refs. 11,13,(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25), which describe the impact of nitrogen in DSS welding, revealed a strong emphasis on explaining nitrogen solubility, solidstate ferrite-to-austenite phase transformations, and gas…”

Section: Literature Review Problem Statementsmentioning

confidence: 99%

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Weldability of Duplex Stainless Steels - Thermal Cycle and Nitrogen Effects

2019

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Section: Literature Review Problem Statementsmentioning

confidence: 99%

“…This finding can be important when using nitrogen or nitrogen-containing mixtures as backing gas (Refs. 13,32,33) and requires more attention in the case of multipass welding, where the root pass is continuously reheated.…”

Section: Pseudo-nitriding Simulations In a Gleeble ® Physical Simulatmentioning

confidence: 99%

Weldability of Duplex Stainless Steels - Thermal Cycle and Nitrogen Effects

2019

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“…For DSS etching different etchant solutions are available (see Table 1); however, Beraha's reagent is widely used for phase selective color etching [26][27][28]. Beraha's reagent paints the ferrite phase dark and the austenite phase remains light.…”

Section: Introductionmentioning

confidence: 99%

Development and Comparison of Quantitative Phase Analysis for Duplex Stainless Steel Weld

Varbai

Pickle

Májlinger

2018

Period. Polytech. Mech. Eng.

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In duplex stainless steels the ideally 1:1 ratio of austenite-to-ferrite phases ensures the outstanding mechanical and corrosion properties compared to other, conventional stainless steel grades. However, this phase balance can be easily shifted to a mostly austenitic or mostly ferritic microstructures, depending on the welding process and heat input. In order to determine the phase ratio, several methods are available to use, such as Feritscope measurements, ASTM E562 manual point count method (on metallographic images) or quantitative image analysis. From these methods, Feritscope measurements cannot be applied to determine phase quantification in the narrow heat affected zone of duplex stainless steel welds – because of the very limited heat input. The manual point count method is very dependent of the assessor and cannot be automated. In this paper a histogram-based image analyzing process was developed, using Beraha's etchant solution. The results were compared to Feritscope measurements and a very good correlation (R2 = 0.9995) was found. This method will give the ability to easily and automatically measure phase ratio in weld metal, heat affected zone or in subsurface regions of multi-pass welds.

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“…Nitrogen can be added to the shielding and backing gases to avoid this occurring. The effects of using nitrogen in the shielding and/or backing gas has been investigated by various authors who have reported an increased resistance to pitting corrosion by increased austenite formation and lower levels of chromium nitrides in the weld metal microstructure [3,[6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…Charpy V-Notch (CVN) tests across a range of low temperatures showed consistent high impact energy values for the weld metal specimens down to-100°C. Westin et al [7] investigated the effects on mechanical and microstructural properties of superduplex (25Cr) welded material using different gas mixtures on 16 mm thick 25Cr base material. The root and cold passes were welded with the GTAW process and flux-cored wire used for filling the joint.…”

Section: Introductionmentioning

confidence: 99%

Effect of nitrogen in backing gas on duplex root weld properties of heavy-walled pipe

Sales¹,

Westin

Colegrove

2016

Weld World

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Duplex stainless steels are increasingly used for offshore subsea components as the technology allows for deeper recovery of oil & gas reserves. Alloy UNS S31803 (EN 1.4462 / UNS S32205) combines high strength with good resistance to pitting and crevice corrosion. This grade is alloyed with nitrogen and has good weldability. For heavy-walled process piping intended for subsea sour service, the properties of the root pass are of high importance. For this reason, the effect of using nitrogen in the backing gas was investigated. Test pieces were manually welded with the gas tungsten arc welding (GTAW) process using ER2209 filler wire. Tensile, bending and hardness testing was carried out and showed acceptable results across all specimens. Higher contents of nitrogen in the backing gas showed more austenite formation and a significant increase in pitting corrosion resistance when compared with pure argon. With Ar + 2% N 2 , there was no pitting, but a small weight loss of 1.7 g/m 2 was measured. 10% N 2 was required to pass both the corrosion tests ASTM G48 Method A (4 g/m 2 ) and ASTM A923 (1 g/m 2 ). The highest average impact toughness was achieved with pure nitrogen as the backing gas.Heavy-walled pipe used for the collection of hydrocarbons subsea are increasingly exposed to harsh conditions and the internal root welds are exposed to high levels of H 2 , H 2 S, and CO 2. The expectation for a lengthy service

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Effect on microstructure and properties of super duplex stainless steel welds when using backing gas containing nitrogen and hydrogen

Cited by 25 publications

References 13 publications

Weldability of Duplex Stainless Steels - Thermal Cycle and Nitrogen Effects

Weldability of Duplex Stainless Steels - Thermal Cycle and Nitrogen Effects

Development and Comparison of Quantitative Phase Analysis for Duplex Stainless Steel Weld

Effect of nitrogen in backing gas on duplex root weld properties of heavy-walled pipe

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