Nitrogen surface enrichment of austenitic stainless steel ISO 5832-1

Austenitic stainless steels, although highly resistant to general corrosion, are susceptible to localized pitting or crevice corrosion. Corrosion resistance and mechanical properties could be enhanced by adding nitrogen to the alloy in solid solution. The methods currently in use involve fusion and solidification of the material, which may often be a deterrent, from the cost–benefit analysis stand point. In this article, the solution heat treatment after plasma nitriding (SHTPN) is presented as a new method to increase the surface nitrogen content in the solid state. The results obtained demonstrated the efficiency of this technique, by which the achieved thickness of the nitrided steel reaches up to 200 μm with 0.45 wt% of nitrogen.