Abstract
The effect of internal hydrogen on ductility of stainless steels, JIS-SUS304 and JIS-SUS316L, was investigated via slow strain-rate tensile tests at the temperature ranged from room temperature (RT) to 77 K. In both steels, the degree of hydrogen embrittlement (HE) was maximized at 193 K and few impacts of hydrogen on the ductility was obtained at 77K. The fracture surface morphologies are linked with the HE degree in order for the discussion of the unique HE mechanism at cryogenic temperature range.