Effect of post-weld heat treatment on microstructure evolution and pitting corrosion behavior of UNS S31803 duplex stainless steel welds

2012 ◽  
Vol 62 ◽  
pp. 42-50 ◽  
Author(s):  
Ziying Zhang ◽  
Zhiyu Wang ◽  
Yiming Jiang ◽  
Hua Tan ◽  
Dong Han ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Corrosion Behavior ◽  
Microstructure Evolution ◽  
Pitting Corrosion ◽  
Post Weld Heat Treatment ◽  
Steel Welds ◽  
Weld Heat

Effect of post-weld heat treatment on thermal diffusivity in UNS S32304 duplex stainless steel welds

2017 ◽  
Vol 2 (88) ◽  
pp. 49-58
Author(s):  
E.G. Betini ◽  
C.S. Mucsi ◽  
T.S. Luz ◽  
M.T.D. Orlando ◽  
M-N. Avettand-Fènoël ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Thermal Diffusivity ◽  
Duplex Stainless Steel ◽  
Welding Process ◽  
Austenite Phase ◽  
Shielding Gas ◽  
Heat Treated ◽  
Steel Welds ◽  
Weld Heat

Purpose: The thermal diffusivity variation of UNS S32304 duplex stainless steel welds was studied after pulsed GTA welding autogenous process without filler addition. This property was measured in the transverse section of thin plates after welding process and post-heat treated at 750°C for 8 h followed by air-cooling. Design/methodology/approach: The present work reports measurements of thermal diffusivity using the laser-flash method. The thermal cycles of welding were acquired during welding by means of k-type thermocouples in regions near the weld joint. The used shielding gas was pure argon and 98% argon plus 2% of nitrogen. The temperature profiles were obtained using a digital data acquisition system. Findings: It was found an increase of thermal diffusivity after welding process and a decrease of these values after the heat treatment regarding the solidified weld pool zone, irrespective of the welding protection atmosphere. The microstructure was characterized and an increase of austenite phase in the solidified and heat-affected zones was observed for post-weld heat-treated samples. Research limitations/implications: It suggests more investigation and new measurements about the influence of the shielding gas variation on thermal diffusivity in the heat-affected zone. Practical implications: The nuclear industry, especially, requests alloys with high thermal stability in pipes for power generation systems and safe transportation equipment’s for radioactive material. Thus, the duplex stainless steel grades have improved this stability over standard grades and potentially increase the upper service temperature reliability of the equipment. Originality/value: After heat treatment, the welded plate with 98%Ar plus 2%N2 as shielding gas presented a thermal diffusivity closer to the as received sample. By means of 2%-nitrogen addition in shielding gas during GTAW welding of duplex stainless steel may facilitate austenite phase reformation, and then promotes stability on the thermal diffusivity of duplex stainless steels alloys.

Effect of post-weld heat treatment on microstructure and corrosion properties of multi-layer super duplex stainless steel welds

2021 ◽  
Vol 63 (9) ◽  
pp. 791-796
Author(s):  
Lei Tian ◽  
Zhanqi Gao ◽  
Yongdian Han
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Welded Joints ◽  
Post Weld Heat Treatment ◽  
Super Duplex Stainless Steel ◽  
Corrosion Properties ◽  
Austenite Content ◽  
Mechanical And Corrosion Properties ◽  
Weld Heat

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.

scholarly journals Effect of the Addition of Nickel Powder and Post Weld Heat Treatment on the Metallurgical and Mechanical Properties of the Welded UNS S32304 Duplex Stainless Steel

2016 ◽  
Vol 21 (2) ◽  
pp. 197-208 ◽  
Author(s):  
Ali Tahaei ◽  
Argelia Fabiola Miranda Perez ◽  
Mattia Merlin ◽  
Felipe Arturo Reyes Valdes ◽  
Gian Luca Garagnani
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Nickel Powder ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
Gtaw Process ◽  
Welding Properties ◽  
Weld Heat

Abstract In this research, the effect of the addition of nickel powder and the application of a post weld heat treatment (PWHT) on the welding properties of the UNS S32304 lean duplex stainless steel were investigated in order to improve the microstructure and mechanical properties. Nickel powder was directly poured inside the joint gap and mixed with the filler metal during the Gas Tungsten Arc Welding (GTAW) process; moreover, the solution heat treatment was performed at 1100 °C for 10 min. The joints were characterized by optical microscopy (OM) and the evolution of the phase percentages in the different zones was studied by means of the image analysis technique. Tensile and hardness tests were carried out on the joints in order to evaluate the improvement of the mechanical properties. The results showed that both the addition of nickel powder during the welding process and the post weld heat treatment made it possible to improve the mechanical properties of the weld joints. PWHT had the best effect in restoring the equal percentage of ferrite and austenite compared to the addition of nickel powder.

Effect of Post Weld Heat Treatment on Mechanical Properties of 17-4-PH Stainless Steel Welds

2015 ◽  
Vol 830-831 ◽  
pp. 181-184
Author(s):  
A. Sam Prabhakar ◽  
M. Agilan ◽  
T. Venkateswaran ◽  
D. Sivakumar ◽  
P.G. Venkatakrishnan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Stainless Steel ◽  
Heat Treatment Condition ◽  
Post Weld Heat Treatment ◽  
Thick Sheet ◽  
Gas Tungsten Arc ◽  
Gtaw Process ◽  
Steel Welds ◽  
Weld Heat

Precipitation hardening stainless steel (17-4-PH) of 3 mm thick sheet was welded by gas tungsten arc welding (GTAW) process using a matching composition filler wire of ER 630. The welds were subjected to various post weld heat treatment (PWHT) cycles viz., H900, H1025 and H1150. Tensile properties (UTS, 0.2% YS, and % EL.), hardness survey across the weld and detailed optical microscopy have been carried-out on as-welded and after different PWHT conditions samples. Results showed that H900 heat treatment condition attained higher mechanical properties than H1025 and H1150.

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