Microstructure and Properties of Lean Duplex Stainless Steel UNS S32101 Welded Joint by Hot Wire TIG Welding

2020 ◽  
Vol 993 ◽  
pp. 466-473
Author(s):  
Liang Liang Bao ◽  
Yong Wang ◽  
Tao Han
Keyword(s):  
Corrosion Resistance ◽  
Base Metal ◽  
Pitting Corrosion ◽  
Welded Joints ◽  
Welded Joint ◽  
Tig Welding ◽  
Hot Wire ◽  
Average Value ◽  
Pitting Corrosion Resistance ◽  
Temperature Heat

Lean duplex stainless steel UNS S32101 was welded by hot wire TIG welding and traditional TIG welding, and nice formed welds with no visible defects were obtained. Metallographic microstructure, phase ratio, mechanical properties and pitting corrosion resistance property of the welded joints were tested. Microstructure analysis showed that the hot wire TIG and traditional TIG welded joints had similar microstructures. The welded metal was composed of ferrite, grain boundary austenite (GBA), Widmanstatten austenite (WA), intragranular austenite (IGA). The high temperature heat affected zone (HTHAZ) consisted of ferrite, GBA and IGA. The low temperature heat affected zone (LTHAZ) had semblable microstructures with base metal. The phase ratio of welded joints was measured by manual point count method. The ferrite/austenite ratio of hot wire TIG welded metal was close to 1:1. The welded joints of hot wire TIG and traditional TIG had same hardness distribution. The hardness of hot wire TIG with an average value of 291 HV10 was a little higher than that of traditional TIG with an average value of 280 HV10. Charpy impact test at -40°C showed that the impact values of hot wire TIG and traditional TIG welded joints meet the standard requirements. The results of chemical weight loss method showed that the corrosion rate of hot wire TIG welded joint was less than 10 mdd. Potentiodynamic polarization method results showed that the pitting corrosion resistance of hot wire TIG welded joints was slightly lower than that of base metal. Solid solution treatment significantly increased the pitting corrosion resistance of welded joints and base metal. The hot wire TIG and traditional TIG had similar microstructure and properties under the same arc power, however the welding speed of hot wire TIG was 1.5 times higher than that of traditional TIG and the welding efficiency was greatly improved.

scholarly journals Corrosion Resistance and Mechanical Properties of TIG and A-TIG Welded Joints of Lean Duplex Stainless Steel S82441 / 1.4662

2016 ◽  
Vol 61 (2) ◽  
pp. 771-784 ◽  
Author(s):  
Z. Brytan ◽  
J. Niagaj
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Pitting Corrosion ◽  
Welded Joints ◽  
Heat Input ◽  
Filler Metal ◽  
Tig Welding ◽  
Lean Duplex Stainless Steel ◽  
Pitting Corrosion Resistance

Abstract This paper presents results of pitting corrosion resistance of TIG (autogenous and with filler metal) and A-TIG welded lean duplex stainless steel S82441/1.4662 evaluated according to ASTM G48 method, where autogenous TIG welding process was applied using different amounts of heat input and shielding gases like pure Ar and Ar+N2 and Ar+He mixtures. The results of pitting corrosion resistance of the welded joints of lean duplex stainless steel S82441 were studied in as weld conditions and after different mechanical surface finish treatments. The results of the critical pitting temperature (CPT) determined according to ASTM G48 at temperatures of 15, 25 and 35°C were presented. Three different surface treatment after welding were applied: etching, milling, brushing + etching. The influence of post weld surface treatment was studied in respect to the pitting corrosion resistance, basing on CPT temperature. Research on TIG welding of lean duplex stainless steel S82441/1.4662 showed a clear influence of the applied shielding gas mixtures, where the addition of 5 to 15% N2 to Ar virtually no effect on the level of resistance to pitting corrosion, only 5% N2 addition has a positive effect, while use of a mixture of 50% Ar + 50% He compared with welding at 100% Ar atmosphere, can significantly reduce the resistance to pitting corrosion. Definite good results were obtained during TIG welding with the participation of activation flux (A-TIG). The weld surface of lean duplex stainless S82441/1.4662 obtained in A-TIG welding without the addition of filler metal has a much lower tendency to pitting corrosion than traditional welds made by TIG method. Pitting corrosion resistance of welds made by A-TIG improved with the increase of the heat input in the tested range of welding current 100-200 A. It was also found that the intensity of the occurrence of pitting does not affect the method of cleaning welds after welding, but the mechanical removal of a thin surface layer of metal significantly reduces their intensity.

scholarly journals Microstructure, roughness, and corrosion resistance of X5CrNi18-10 austenite stainless steel welded joint

2021 ◽  
pp. 7-7
Author(s):  
Bojana Radojkovic ◽  
Bore Jegdic ◽  
Jovanka Kovacina ◽  
Sanja Stevanovic ◽  
Dunja Marunkic
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Weld Metal ◽  
Base Metal ◽  
Pitting Corrosion ◽  
Welded Joint ◽  
Electrochemical Testing ◽  
Limit Value ◽  
Before And After ◽  
Degree Of Sensitization

The influence of the microstructure of the X5CrNi18-10 stainless steel welded joint on its resistance to general, pitting, and intergranular corrosion was analysed. The structure of weld metal, heat affected zone (HAZ) and base metal before and after electrochemical testing was analysed using SEM/EDS. The influence of the roughness level of the welded joint on its resistance to the mentioned types of corrosion was examined as well. Although the degree of sensitization of HAZ was significantly lower than the limit value, HAZ showed a noticeably greater tendency to general and pitting corrosion than weld metal and base metal. Polishing has been shown to significantly improve the corrosion resistance of HAZ than in the case of other parts of the welded joint.

scholarly journals Testing of intergranular and pitting corrosion in sensitized welded joints of austenitic stainless steel

10.30544/274 ◽  
2017 ◽  
Vol 23 (2) ◽  
pp. 109-117 ◽  
Author(s):  
Bore V. Jegdic ◽  
Biljana Bobić ◽  
Milica Bošnjakov ◽  
Behar Alić
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Weld Metal ◽  
Base Metal ◽  
Pitting Corrosion ◽  
Heat Affected Zone ◽  
Intergranular Corrosion ◽  
Chromium Concentration ◽  
Pitting Corrosion Resistance

Pitting corrosion resistance and intergranular corrosion of the austenitic stainless steel X5Cr Ni18-10 were tested on the base metal, heat affected zone and weld metal. Testing of pitting corrosion was performed by the potentiodynamic polarization method, while testing of intergranular corrosion was performed by the method of electrochemical potentiokinetic reactivation with double loop. The base metal was completely resistant to intergranular corrosion, while the heat affected zone showed a slight susceptibility to intergranular corrosion. Indicators of pitting corrosion resistance for the weld metal and the base metal were very similar, but their values are significantly higher than the values for the heat affected zone. This was caused by reduction of the chromium concentration in the grain boundary areas in the heat affected zone, even though the carbon content in the examined stainless steel is low (0.04 wt. % C).

scholarly journals The Pitting Corrosion Behavior of the Austenitic Stainless Steel 308L-316L Welded Joint

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1258
Author(s):  
Jinshan He ◽  
Shiguang Xu ◽  
Wenxin Ti ◽  
Yaolei Han ◽  
Jinna Mei ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Statistical Analysis ◽  
Austenitic Stainless Steel ◽  
Passive Film ◽  
Pitting Corrosion ◽  
Welded Joint ◽  
Weld Zone ◽  
Electrochemical Tests ◽  
Pitting Corrosion Resistance

The pitting corrosion resistance of the austenitic stainless steel 308L-316L welded joint was investigated by electrochemical tests. It is found that the weld zone was the most critical for pits to initiate in the welded joint due to relatively instable passive film with few Mo and inhomogeneous passive film induced by multiple (Mn, Al, and Si) oxides and continuous network of 13.94 vol.% δ ferrites. By statistical analysis, 53.8% pits initiated at (Mn, Al, and Si) oxides, 23.0% in austenite, and 23.2% at interface between ferrite and austenite. In addition, heat-affected zone was prone to have pitting corrosion compared with the base metal since residual strain was much higher in the region.

Microstructure and Corrosion Resistance of Dissimilar Welded Joints between Duplex Stainless Steel and Austenitic Stainless Steel

2012 ◽  
Vol 570 ◽  
pp. 43-51
Author(s):  
Shao Gang Wang ◽  
Yan Li ◽  
Wei Guo Zhai
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Duplex Stainless Steel ◽  
Pitting Corrosion ◽  
Welded Joints ◽  
Microstructural Characterization ◽  
Optical Microscope ◽  
Dissimilar Metals ◽  
Pitting Corrosion Resistance

The dissimilar metals components of duplex stainless steels are more and more used in engineering fields recently. But the welding of dissimilar metals is more a challenge than that of similar metals. The joints of dissimilar metals between 2205 duplex stainless steel and 304 austenitic stainless steel were produced by tungsten inert gas arc welding (GTAW) with welding wire ER2209 and ER309, respectively. The microstructural characterization of welded joints is systematically analyzed by using optical microscope and X-ray diffractometer. The pitting corrosion resistance of the joints is evaluated by electrochemical test. Results show that the microstructure of joint consists of austenite and ferrite, and no detrimental phases precipitate in the weldment. The biphase ratio of austenite (γ) / ferrite (α) is adequate both in weld metal and heat-affected zone (HAZ), which is advantageous to the performance of welded joints. The weld metals have relatively lower pitting corrosion resistance compared with the 2205 base metal, and the pitting corrosion resistance of the joint produced with ER2209 is better than that of the joint with ER309 in chloride solution.

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