Comparative Study on Hydrogen Embrittlement Susceptibility in Heat-Affected Zone of TP321 Stainless Steel

摘要

TP321 stainless steel is widely used in hydrogenation refining pipes owing to its excellent performance of creep resistance and high-temperature resistance. In this study, the thermal simulation tests were carried out for the welding heat-affected zone (HAZ) of TP321 stainless steel at the temperatures of 1300 °C, 1100 °C, and 850 °C. Slow strain tensile tests were conducted under the condition of electrolytic hydrogen charging (EHC), and the metallographic microstructure of the cracks as well as the morphology of the fractures were analyzed in detail. The result showed that hydrogen could change the fracture mode of the tensile specimen. Hydrogen significantly decreased the plastic deformation capability of HAZ and the reduction of area after the fracture decreased by 58%, 41%, and 45% at 1300 °C, 1100 °C, and 850 °C, respectively. The existence of 8 ferrite was considered to be the main reason for the aggravation of hydrogen-induced plasticity loss.