Mechanical Properties of Nitrogen-Alloyed High Strength Austenitic Stainless Steel for Automotive Applications

For potential applications in automotive structural parts, metastable austenitic stainless steels provide important technical merits in material properties such as strength-to-weight ratio, strain hardening capacity, strain rate sensitivity, fatigue resistance and formability. Nitrogen-alloyed AISI 200 series metastable steels are promising in this application as they are more economical solution with better mechanical properties compared to conventional 300 series steels. It has been shown that additional solution strengthening can be obtained by nitrogen alloying, maintaining the strain hardening capacity and high ductility of metastable steel. Moreover, nitrogen-alloyed steel shows effective strengthening by grain refining, providing alternative way to temper the steel in addition to conventional cold working.