Abstract:The fatiguecrackgrowth behaviors of AISI316Lstainlesssteel (SS) welds in air and gaseous hydrogen were evaluated, and further compared with the base plate. In air, the fatiguecrackgrowth rate (FCGR) of the weld after heat-treatment at 1050 oC/1 h was similar to that of the base metal. Furthermore, all specimens became susceptible to hydrogen-accelerated crackgrowth. Mainly quasi-cleavage fracture related with the strain-induced martensite accounted for the accelerated crackgrowth in hydrogen. A smaller amount of martensite in the weld was responsible for the decreased susceptibility to hydrogen-enhanced fatiguecrackgrowth relative to the base metal.