Promoting austenite formation in laser welding of duplex stainless steel—impact of shielding gas and laser reheating

Baghdadchi, Amir; Hosseini, Vahid A.; Hurtig, Kjell; Karlsson, Leif

doi:10.1007/s40194-020-01026-7

Cited by 26 publications

(15 citation statements)

References 39 publications

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“…Baghdadchi et al reported that changing the shielding gas from argon to nitrogen can increase the austenite content from 22 to 39% in the weld metal and 33% in the HAZ in laser welding duplex stainless steel [31].…”

Section: Resultsmentioning

confidence: 99%

Prediction of Mechanical Properties as a Function of Welding Variables in Robotic Gas Metal Arc Welding of Duplex Stainless Steels SAF 2205 Welds Through Artificial Neural Networks

Payares-Asprino

2021

Advances in Materials Science

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Dual-phase duplex stainless steel (DSS) has shown outstanding strength. Joining DSS alloy is challenging due to the formation of embrittling precipitates and metallurgical changes during the welding process. Generally, the quality of a weld joint is strongly influenced by the welding conditions. Mathematical models were developed to achieve high-quality welds and predict the ideal bead geometry to achieve optimal mechanical properties. Artificial neural networks are computational models used to address complex nonlinear relationships between input and output variables. It is one of the powerful modeling techniques, based on a statistical approach, presently practiced in engineering for complex relationships that are difficult to explain with physical models. For this study robotic GMAW welding process manufactured the duplex stainless steel welds at different welding conditions. Two tensile specimens were manufactured from each welded plate, resulting in 14 tensile specimens. This research focuses on predicting the yield strength, tensile stress, elongation, and fracture location of duplex stainless steel SAF 2205 welds using back-propagation neural networks. The predicted values of tensile strength were later on compared with experimental values obtained through the tensile test. The results indicate <2% of error between observed and predicted values of mechanical properties when using the neural network model. In addition, it was observed that the tensile strength values of the welds were higher than the base metal and that this increased when increasing the arc current. The welds’ yield strength and elongation values are lower than the base metal by 6%, ~ 9.75%, respectively. The yield strength and elongation decrease might be due to microstructural changes when arc energy increases during the welding.

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Section: Resultsmentioning

confidence: 99%

Prediction of Mechanical Properties as a Function of Welding Variables in Robotic Gas Metal Arc Welding of Duplex Stainless Steels SAF 2205 Welds Through Artificial Neural Networks

Payares-Asprino

2021

Advances in Materials Science

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“…Rapid cooling will restrict the formation of austenite and disturb the optimal pha balance in DSS. In Amir Baghdadhi's experiments, laser reheating is used to avoid lo austenite fraction and nitride formation [25]. Compared with air, the cooling rate of t molten pool of underwater laser welding is faster and the temperature gradient is larg Therefore, in the experiment, the method of reducing the welding speed was used to i prove the welding heat input, and a microstructure similar to that in air was obtaine Figure 5 presents the microstructure of S32101 stainless steel welds under different shie ing gas compositions.…”

Section: Microstructural Characterizationmentioning

confidence: 99%

“…Rapid cooling will restrict the formation of austenite and disturb the optimal phase balance in DSS. In Amir Baghdadhi's experiments, laser reheating is used to avoid low austenite fraction and nitride formation [25]. Compared with air, the cooling rate of the molten pool of underwater laser welding is faster and the temperature gradient is larger.…”

Section: Microstructural Characterizationmentioning

confidence: 99%

Investigation on Microstructure and Properties of Duplex Stainless Steel Welds by Underwater Laser Welding with Different Shielding Gas

et al. 2021

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Taking S32101 duplex stainless steel as the research object, underwater laser wire filling welding technology was used for U-groove filling welding. The influence of different shielding gas compositions on the ferrite content, microstructure, mechanical properties and pitting corrosion resistance was studied by simulating a water depth of 15 m in the hyperbaric chamber. The results show that, under the same process parameters, the size and proportion of austenite in the weld when using pure nitrogen as the shielding gas are larger than those protected by other shielding gases. In a mixed shielding gas, the increase in nitrogen content has little effect on the strength and toughness of the weld. Regardless of the shielding gas used, the base metal was the weakest part of the weld. At the same time, intermetallic inclusions have an adverse effect on the impact toughness of the weld. The pitting corrosion resistance of the welds depends on the Cr2N content in the heat-affected zone. The precipitation and enrichment of Cr2N causes local chromium deficiency, which is the main factor for the weak pitting corrosion ability of the heat-affected zone. Pure nitrogen protection has a better corrosion resistance than other gas protection.

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“…The effect of mixing 2% nitrogen added 98% argon as backing gas for greater than 10 mm thickness, improving the corrosion resistance (Sales et al, 2016). Furthermore, several authors reported utilising nitrogen in the shielding and backing gas, leading to an increase of the austenite formation and lower chromium nitrides in the weld metal microstructure (Baghdadchi et al, 2020;Betini et al, 2019;Gozarganji et al, 2021;Liu et al, 2020;Matsunaga et al, 2013;Muthupandi et al, 2005). In contrast, the unbalance A/F transformation still occurred even with mixing a small percentage of nitrogen in argon for shielding gas or backing gas because the solubility and diffusion kinetics of atomic nitrogen in the solid-state is not in the liquid phase.…”

Section: Introductionmentioning

confidence: 99%

“…Although many studies on the detrimental phases such as chromium nitride and austenite precipitation in DSS while welding process has been reported (Baghdadchi et al, 2020;Betini et al, 2019;Gozarganji et al, 2021;Karlsson et al, 1995;Lippold & Kotecki, 2005;Liu et al, 2020;Matsunaga et al, 2013;Muthupandi et al, 2005;Ramirez et al, 2003), not much work has been done to simplify the DSS's welding method by reducing backing gas consumption. In this research, the authors simplified its method by varying sequences of backing gas.…”

Section: Introductionmentioning

confidence: 99%

Reduction of the Backing Gas Sequence as a Facile Method to Improve Corrosion Resistance in Duplex Stainless Steel (DSS) Weldment

Laksono¹,

Kurniyanto²,

Sadewa³

et al. 2021

JST

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Duplex stainless steel (DSS) is an important material used for corrosion resistance in various harsh environment plants such as petrochemical, offshore subsea component, and other chemical industries. An approximately equal amount of austenite and ferrite (A/F) ratio grants good mechanical properties and rust protection on. The detrimental intermetallic phase frequently occurs due to an unbalanced A/F ratio caused by the welding’s thermal cycle. Backing gas is commonly applicable in the field combined Gas Tungsten Arc Welding (GTAW) process. However, the use of backing gas to complete a single weld from root to cap joint required huge additional costs for consumables. Maintaining the thermal cycle in the welding parameter and GTAW process with ER2209 filler metal for DSS below 10 mm thick can reduce the backing gas sequence. The research aims to efficiently substitute full backing gas consumption, which meets a desirable quality in terms of corrosion resistance. The effect of backing gas reduction was studied. All specimens were tested by visua Vickers microhardness, metallography, ferrite content measurement, and electrochemical corrosion test. The visual test shows no defects beyond the range of the ASME IX acceptance and criteria. The evaluation comes from the ferrite scope and electrochemical corrosion test. The backing gas on the root weld shows a balance A/F ratio of around 38% ferrite content accepted in various standards. The backing gas sequence on the root until filler-pass obtained 0.04 mm/year, which is the desirable corrosion resistance and met the requirement of ASTM A932.

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Promoting austenite formation in laser welding of duplex stainless steel—impact of shielding gas and laser reheating

Cited by 26 publications

References 39 publications

Prediction of Mechanical Properties as a Function of Welding Variables in Robotic Gas Metal Arc Welding of Duplex Stainless Steels SAF 2205 Welds Through Artificial Neural Networks

Prediction of Mechanical Properties as a Function of Welding Variables in Robotic Gas Metal Arc Welding of Duplex Stainless Steels SAF 2205 Welds Through Artificial Neural Networks

Investigation on Microstructure and Properties of Duplex Stainless Steel Welds by Underwater Laser Welding with Different Shielding Gas

Reduction of the Backing Gas Sequence as a Facile Method to Improve Corrosion Resistance in Duplex Stainless Steel (DSS) Weldment

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