Effect of low temperature on hydrogen-assisted crack propagation in 304L/308L austenitic stainless steel fusion welds

摘要

Effects of low temperature on hydrogen-assisted cracking in 304L/308L austenitic stainless steel welds were investigated using elastic-plastic fracture mechanics methods. Thermally precharged hydrogen (140 wppm) decreased fracture toughness and altered fracture mechanisms at 293 and 223 K relative to hydrogen-free welds. At 293 K, hydrogen increased planar deformation in austenite, and microcracking of 8-ferrite governed crack paths. At 223 K, low temperature enabled hydrogen to exacerbate localized deformation, and microvoid formation, at austenite deformation band intersections near phase boundaries, dominated damage initiation; microcracking of ferrite did not contribute to crack growth.