Controlling the grain size and carbide precipitation for superior yield strength and hydrogen embrittlement resistance in 301 austenitic stainless steel

Abstract

This study aimed to enhance the yield strength and hydrogen embrittlement resistance of AISI 301 stainless steel through the grain refinement and carbide control. Cryogenic rolling coupled with reversion annealing treatment in low temperature were conducted for grain size reduction and formation of fine precipitates. Yield strength significantly increased with grain refinement, while susceptibility to hydrogen embrittlement was also improved with carbide formation. These carbides were identified as Cr-rich precipitates, which were formed near the grain boundaries to hinder the hydrogen diffusion during hydrogen charging and tensile test. It mitigated the occurrence of hydrogen-induced crack mainly initiated and propagated along the grain boundaries, thereby enhancing the hydrogen embrittlement resistance. These finding highlights the significance of grain refinement and precipitate control as effective strategies for enhancing the mechanical properties and hydrogen embrittlement resistance of 301 stainless steel. Local segregation of hydrogen was minimized through the effective control of grain size and fine precipitates. It resulted in enhancement of hydrogen embrittlement resistance as well as the yield strength, overcoming the typical trade-off relationship of strength and hydrogen embrittlement susceptibility.