Microstructural properties controlling hydrogen environment embrittlement of cold worked 316 type austenitic stainless steels

Austenitic stainless steels with three different nickel contents were cold worked to various forming degrees at various temperatures to obtain a wide variety of cold worked microstructures. Dislocation density analyses using the Williamson-Hall method provide first indications that strain hardening using technically relevant cold forming parameters increases the susceptibility of austenitic stainless steels to hydrogen environment embrittlement mainly by creating a microstructure with a “critical” amount of dislocations. Although an effect of prior-existing martensite may not be totally excluded, this effect seems to be minor compared to the effect of dislocation substructure. Macroscopic residual stresses have no significant influence on the susceptibility of cold worked austenitic stainless steels to hydrogen environment embrittlement in tensile tests.