Surface hardening for austenitic stainless steels based on carbon solid solution

A novel low temperature carburising approach for austenitic stainless steels, the NV Pionite process, is described. The formation of a metal fluoride layer on the surface before carburising allows carbon to be introduced into the workpiece by, gas carburising at 450-500degreesC. Laboratory trials using 316 have been conducted. A single phase expanded austenite diffusion layer with surface microhardness of 810 HV0.05 and good corrosion properties is produced.