Stress-induced failure of high-strength steels in environments containing hydrogen sulphide

Abstract

The pre-cracked cantilever beam test is a sensitive means of evaluating the relative susceptibilities of different steels to stress-Induced failure in H₂S-containing environments. This, test indicated that a 12Ni 5Cr.3Mo maragmg stee1 is considerably more resistant to stress-induced crackining than the low-alloy steels 0Ni 1Cr 2Mo and 2Ni 1Cr 3Mo. For low-alloy steels with no applied potential the failure appears to be caused predominantly by hydrogen embrittlement. Impressed anodic or cathodic potentials have no effect on the time to Failure of low-alloy steels where as a zone of immunity exists for maraging steel with Impressed potentials Within the approximate range −0·6 to −1·0 V. This suggests that the maraging steel is less susceptible to hydrogen embrittlement than the quenched and tempered low-alloy steels. Permeability studies indicate that stress-induced failure is related to the ability of the steel to transmit hydrogen and to the nature of hydrogen traps in the steel.