232 Influence of Hydrogen on Fatigue Crack Tip Plasticity of Austenitic Stainless steels

Abstract

The influence of hydrogen on fatigue crack tip plasticity of an austenitic stainless steel, SUS304, was investigated after exposing it to high-pressure hydrogen gas environment. The fatigue crack growth rate in the hydrogen-charged specimen was accelerated and hydrogen decreased the crack tortuosity and the crack opening displacement. Slip bands were lower and more discrete in the hydrogen-charged specimen than in the uncharged specimen. The hydrogen-charged specimen had less asperity along the crack on its surface compared with the uncharged specimen. These results suggest that hydrogen caused slip localization at crack tip and accordingly the acceleration in crack growth rate.