Effects of Salt Bath Nitriding Process on AISI 309 Stainless Steel

Abstract

AISI309 stainless steel is a type of austenitic stainless steel that contains a high percentage of chromium and nickel, along with a small amount of manganese. It is designed to be used in high-temperature applications, such as in furnace parts and heat exchangers. Low temperature salt bath nitriding process was carried out on AISI 309 stainless steel at 550°C for time duration of 80, 160 and 240 minutes. The characteristics of the nitride surface were thoroughly assessed. The microstructure and phase components of the nitrided surface revealed a hardened layer of chromium nitride and iron nitride on the specimen surface. The case depth and the surface hardness were strongly influenced by the alloying components. To analyze the wear, a pin on disc machine was utilized and the wear test was carried out. From the wear test, wear loss were determined. Scanning electron microscopy revealed the variation between loss of material and the base material. A specimen which is untreated is kept aside and comparisons of results were done with nitrided samples.