Abstract
In this study, hydrogen embrittlement of a new stainless steel, STH2, with reduced amounts of Ni and Mo has been examined with respect to the effects of tungsten inert gas (TIG) welding and cold rolling technologies. Tensile tests at -40℃ were conducted for specimens containing around 30 ppm hydrogen precharged by exposure in 10 MPa hydrogen gas at 300℃ after TIG welding and 20% cold rolling. Slow strain rate tensile (SSRT) properties were evaluated in high pressure hydrogen gas up to 70 MPa at -40℃ after 70% cold rolling. At -40℃, no significant elongation drop due to hydrogen charging was observed, and about 100% of relative elongation of specimens heat-treated in air with the same heat pattern was obtained. Elongation of 70% cold-rolled sheets increased with increasing hydrogen gas pressure up to 70 MPa more than in a 0.1 MPa N2 atmosphere. It was confirmed that STH2 even when subjected to TIG welding and cold rolling has excellent properties not only with respect to internal hydrogen of around 30 ppm but also in high pressure hydrogen gas.
