Nitrogen Alloyed Austenitic Ni-free Stainless Steel For Additive Manufacturing

Nitrogen alloyed austenitic nickel-free stainless steel (ANFSS) is one of the most promising group of materials for consumer and health care products. They can be used to substitute not only conventional AISI 316L, but also titanium and Co-Cr alloys. Previously the utilization of nitrogen alloyed materials has been limited due to high work hardening rate. Recent developments in powder metallurgy, e.g., additive manufacturing (AM), are offering economically feasible net shape manufacturing routes to go around machining related problems. In the present study a viable processing route for ANFSS powder is introduced. It includes gas atomization and AM of test specimens by laser- and sinter-based methods. Special attention is paid on controlling the nitrogen content in different processing steps. The results show that by proper selection of processing parameters, the nitrogen content can be kept in desired level, thereby controlling the mechanical properties of ANFSS alloys.