Effect of H2 Gas Environment on Low Cycle Fatigue Crack Initiation and Damage Accumulation of 304 Stainless Steel

Abstract

Notched compact tension specimen of 304 stainless steel (0.8CT, notch tip radius of 1mm, thickness of 6mm) was low-cycle-fatigued at room temperature at stress ratio of -1 in 99.9999% H2 and in pure air at 1 and 0.1 Hz at apparent stress intensity factor of 34.4MPa . The H2 acceleration of both crack initiation and growth at notch is significant: 3-4 times faster than pure air. The accumulated plastic zone was analyzed by the recrystallization technique. It is shown that the accumulated plastic zone in H2 is smaller than in pure air.