2008 Volume 57 Issue 11 Pages 1084-1090
This study aims to evaluate characteristics of hydrogen embrittlement cracking (HEC) of sensitized duplex stainless steel with simulated heat-affected zone (HAZ). The HEC of the steels, aged for 20hr at 650°C, 750°C and 800°C, were studied using a testing machine which can control the stress intensity factor, K, for the precracked compact type (CT) specimens subjected to hydrogen charging. Fracture mechanisms were studied by acoustic emission (AE) method in conjunction with metallographic observation. Fracture toughness, Kc, for the steel aged at 650°C was higher than those of others. The steel aged at 650°C, with hardened ferrite phase, suffered hydrogen-induced brittle cracks in front of main crack, while austenite phase exhibited ductile fracture. For the steels aged at 750°C and 800°C, both the ferrite and sigma phase suffered hydrogen-induced microcracks.
