Effect of Hydrogen Charging on the Crack Propagation and Crack Branching in Delayed Failure of Ni-Cr-Mo Steel

Abstract

Delayed failure tests were carried out on Ni−Cr−Mo steel quenched and tempered at 673 K in aNaCI aqueous solution in hydrogen charging condition， and the crack branching as well as crack propagation behaviors were investigated．The crack propagation rate dα／d increases with increase in cathode charging current density， ゼ，and da／d云increases to a maximum and then decreases with increase in the increasing rate of stress intensity factor，左． The stress intensity factor at crack branching，1(IB， decreases to a