Behavior of Some Stainless Nitrided Austenite Steel Types to Corrosion and Abrasion

Résumé

By nitriding, stainless austenite steel types can become surface hardened. Hardness can be greater at more than 1000 HV₀₀₅ when the composition layer made of complex nitrides is obtained and more reduced till 500 HV₀₀₅ when a diffusion layer made of highly alloyed austenite including nitrogen is obtained. The tests in salt fog for resistance to corrosion show a decrease of this resistance to corrosion from Perfectly resistant materials (appreciation mark 1.1) to Very resistant materials (appreciation mark 2.1 or 2.2), for the nitrided steel types which form complex nitrides layers and which can keep the resistance to corrosion in the group of perfectly resistant materials or an insignificant decrease for the steel type that forms a diffusion layer. The tests for resistance to abrasion show a decrease of two or three times for mass losses this meaning a significant increase in resistance. This is as important as surface treatment and thickness of nitrided layer are bigger. The steel, the surface treatment, so the type of diffusion surface layer with austenite structure or the combinations with nitrides complex separations will be chosen depending on aggressive factors weight for corrosion and abrasion of the environment in which the product is working.