scholarly journals Influence of MIG/MAG Welding Process on Mechanical and Pitting Corrosion Behaviors on the Super-Duplex Stainless Steel SAF 2507 Welded Joints

2018 ◽  
Vol 09 (02) ◽  
pp. 228-245 ◽  
Author(s):  
Bruno Leonardy S. Lopes ◽  
Samuel F. Rodrigues ◽  
Eden S. Silva ◽  
Gedeon S. Reis ◽  
Waldemir dos P. Martins ◽  
...  
2021 ◽  
Vol 413 ◽  
pp. 127095
Author(s):  
Oriana Palma Calabokis ◽  
Yamid Núñez de la Rosa ◽  
Carlos M. Lepienski ◽  
Rodrigo Perito Cardoso ◽  
Paulo César Borges

2010 ◽  
Vol 658 ◽  
pp. 380-383 ◽  
Author(s):  
Ying Han ◽  
De Ning Zou ◽  
Wei Zhang ◽  
Jun Hui Yu ◽  
Yuan Yuan Qiao

Specimens of 2507 super-duplex stainless steel aging at 850°C for 5 min, 15 min and 60 min were investigated to evaluate the pitting corrosion resistance in 3.5% NaCl solution at 30°C and 50°C. The results are correlated with the microstructures obtained with different aging time. The precipitation of σ phase remarkably decreases the pitting corrosion resistance of the steel and the specimen aged for 60 min presents the lowest pitting potential at both 30°C and 50°C. With increasing the ambient temperature from 30°C to 50°C, the pitting potential exhibits a reduction tendency, while this tendency is less obviously in enhancing the ambient temperature than in extending the isothermal aging duration from 5 to 60 min. SEM analysis shows that the surrounding regions of σ phase are the preferable sites for the formation of corrosion pits which grew up subsequently. This may be attributed to the lower content of corrosion resistance elements in these regions formatted with σ phase precipitation.


Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 294
Author(s):  
Shuang Liu ◽  
Chaohua Yue ◽  
Xi Chen ◽  
Qiuhua Zhu ◽  
Yiyou Tu

The pitting corrosion resistance of S32750 super duplex stainless steel, annealing treated at temperatures of 950–1200 °C for 20–60 min, was investigated using potentiodynamic polarization tests. The results show that the volume fractions of ferrite in the S32750 duplex stainless steel increased from 48.9% to 68.4% as annealing temperatures increased from 950 to 1200 °C. The pitting potential of the sample increased first and then decreased from an annealing temperature of 950 to 1050 °C, and the highest pitting potential was observed after annealing at 1050 °C for 35 min. The pitting corrosion resistance of S32750 stainless steel is due to the combination of pitting resistance equivalent number (PREN) value, phase fraction and grain boundary area fraction, and the imbalance of corrosion potential.


Author(s):  
A. Arunmani ◽  
T. Senthilkumar

In engineering industries and heavy manufacturing plants, fatigue life of joints plays a pivotal role in determining the overall life span of the welded joint. In this paper, an advanced fusion joining technique, namely activated tungsten inert gas welding, was used for joining UNS S32750 super duplex stainless steel, with ZnO as activation flux. For the enhancement of fatigue resistance of joints, important welding process parameters were fluctuated according to a developed central composite design model. Empirical relationships were developed between the process parameters and the fatigue strength of the joints, which was correlated with the number of cycles to failure (NCF). Using analysis of variance, the significance of the developed fatigue model was ascertained. Using response surface methodology, optimization of process parameters for enhancement of fatigue resistance was done. It was observed that at the optimized activated tungsten inert gas weld process parameters of travel speed of welding torch at 69.85 mm/min, weld current at 125.20 A, and shielding gas flow rate at 14.77 L/min, a high fatigue life of 7.66396 × 108 NCF was obtained and the model was validated to very high predictability. Microstructural variations in the fatigue-tested specimens were evaluated for identifying the grain modifications.


2013 ◽  
Vol 746 ◽  
pp. 467-472 ◽  
Author(s):  
In June Moon ◽  
Bok Su Jang ◽  
Jin Hyun Koh

The purpose of this study was to investigate the effect of heat treatment (930°C, 1080°C, 1230°C) followed by quenching on the pitting corrosion resistance, sigma phase precipitation, and microstructural change of a super duplex stainless steel (UNS S32750) welds made by gas tungsten arc (GTA). Based on the microstructural examination, the σ phase was formed in welds heat treated at 930°C while there were little σ phases formed in welds experienced the relatively fast cooling from 1080°C and 1230°C. Accordingly, the most weight loss due to pitting corrosion occurred in the as received base and weld metals heat treated at 930°C. It was confirmed that the pitting corrosion occurred in the phase boundaries of ferrite/sigma and austenite/sigma.


2021 ◽  
Vol 63 (9) ◽  
pp. 791-796
Author(s):  
Lei Tian ◽  
Zhanqi Gao ◽  
Yongdian Han

Abstract To investigate the influence of post-weld heat treatment on the microstructure and corrosion properties of super duplex stainless steel welded joints, multi-layer multi-pass welding of 2507 super duplex stainless steel by tungsten argon arc welding was performed using an ER2594 welding wire. The microstructures of the welded joints before and after post-weld heat treatment at 1150 °C, 1170 °C and 1190 °C were observed, and the mechanical and corrosion properties were tested. The post-weld heat treatment changed the austenite content and morphology of the welded joint and improved the corrosion resistance of different parts of the weld metal. The choice of various solution heat treatment temperatures affected the change in austenite content in the weld zone and the degree of diffusion and homogenization of the alloy elements. After post-weld heat treatment at 1170 °C, the two-phase ratios in each area of the weld were the most suitable and uniform, and the overall mechanical and corrosion properties of the joint were more uniform.


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