Abstract
Austenitic stainless steels are critical in the modern economies with applications ranging from food processing and cryogenic machinery to medical implants and aerospace instrumentation. Tough, resistant to low-temperature embrittlement and many forms of corrosion, these steels are, nevertheless, prone to scratching and galling in service. Case hardening was found to be effective when combined with corrosive surface treatments or in low-pressure, direct plasma-ion discharges, but inhibited in simple atmospheric-pressure furnaces. This paper presents preliminary evaluation of new, rapid (3-4 hrs) nitriding and carbonitriding treatments at low- (500-565°C) and high- (1100°C) temperature ranges involving injection of high-voltage, electric arc-activated, N2-based, NH3 and hydrocarbon gas mixes to the conventional box furnace. Reported data includes characterization of stainless steel product layers using SEM-EDS, XRD, OM, Leco elemental analysis, and microhardness profiling, as well as laser gas analysis of the residual furnace atmosphere.
