Depending on the application, there are various process options, with the aim of achieving the desired properties.
During the Stainihard® process the surface will be enriched with nitrogen and carbon in a special way. With austenitic stainless steel this is not easily possible. Nitrogen and carbon diffuse at a low temperature (<450°C) in the product surface. The result is a very high surface hardness (1200-1400HV0.05) without negatively affecting the corrosion resistance!
The Stainihard® layer is an expanded austenite zone (also called S-phase). This zone consists of the relevant stainless-steel material with a supersaturation of nitrogen and carbon. Because of this supersaturation, compressive stresses arise. This increases the hardness considerably, without negatively affecting the corrosion resistance. The reason is, with Stainihard® NC the formation of chromium nitride (CrN) and / or chromium carbide (CrC) is suppressed (expanded austenite). This in contrast to the classical nitriding processes such as salt bath and plasma nitriding, where the corrosion resistance will decrease considerably as a result of the formation of this chromium nitride and carbides!
The depth of this expanded austenite layer formed by Stainhard is partly dependent on the chosen stainless-steel material, the deformation degree and the surface condition.