Hydrogen-induced cracking of weld metal of austenitic stainless steels

For 308L and 347L weld metals of austenitc stainless steels (ASS), hydrogen induced cracking (HIC) occurred during dynamically charging under constant load. The threshold stress intensity for HIC, K-IH, decreased linearly with the logarithm of the concentration of diffusible hydrogen C-0 in the weld metals and the rolled plate of type 304L ASS, i.e., K-IH=85.2-10.7lnC(0) (308L), K-IH=76.1-9.3InC(0)(347L), and K-IH=91.7-10.1InC(0)(304L). The fracture mode for HIC in the three type of ASS changed from ductile to brittle with the decrease in the applied stress intensity K-I or/and the increase in C-0. The boundary line between ductile and brittle fracture surfaces was K-I-54+25exp(-C-0/153)=0.