Nitrocarburising of AISI 316 Stainless Steel at Low Temperature

In this study, a low-temperature salt bath nitrocarburising method was used to modify the surface of AISI 316 stainless steel. The results showed that nitrogen and carbon atoms were coinstantaneously diffused into the austenite lattice during the nitrocarburising treatment. A supersaturated solid solution with nitrogen and carbon atoms, which has a face centre tetragonal structure, was formed. Moreover, the surface hardness of salt bath nitrocarburised AISI 316 reached 900 HV0.05 which was four times the hardness of the untreated sample. By adjusting treating time and treating temperature, both the surface hardness and the corrosion resistance of the stainless steel were enhanced. Overall, a nitrocarburised layer having the advantages of high hardness, favourable hardness gradient and excellent corrosion resistance was obtained on AISI 316 stainless steel surface by using low-temperature salt bath nitrocarburising.