Abstract: 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, KIH, decreased linearly with the logarithm of the concentration of diffusible hydrogen C0 in the weld metals and the rolled plate of type 304L ASS, i.e., KIH=85.2-10.7ln C0 (308L),KIH=76.1-9.3ln C0(347L), and KIH=91.7-10.1ln C0(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 KI or/and the increase in C0. The boundary line between ductile and brittle fracture surfaces was KI-54+25exp(-C 0/153)=0.

Key words: Austenitic stainless steel, Hydrogen induced cracking, Fracture