Active-Screen Plasma Nitriding of an Austenitic Stainless Steel Small Thin Rolled Plate

The purpose of this study is to clarify the mechanical properties of the expanded austenite (S phase) formed in austenitic stainless steel (ASS). A small thin rolled plate of SUS304 with 0.5 mm thickness was used as test sample. The test sample was nitrided by active screen plasma nitriding (ASPN) at low processing temperature of 400 °C and 450 °C during 4 h processing time. S phase was formed on the surface of the test sample. The surface hardness of ASPN sample was higher than that of untreated sample. Furthermore, tensile tests and fracture surface observations revealed that the tensile strength was also improved compared to untreated samples.