Influence of Nitriding Treatment on Microstructure and Corrosion Behavior of 904L Stainless Steel

In order to explore the effective method to improve the strength of 904L super austenitic stainless steel (904LSS) without reducing its corrosion resistance, plasma nitriding and nitrocarburizing were used to nitride 904LSS, and the surface morphology, microstructure and corrosion resistance of 904LSS after nitriding treatment were studied. The results showed that the surface hardness of the samples was improved obviously after the two kinds of nitriding treatment, the surface hardness of the sample after plasma nitriding was higher than the one after nitrocarburizing. The nitrided layer after the two kinds of nitriding treatment was composed of compound layer and diffusion layer. The corrosion resistance of 904LSS decreased after the two kinds of nitriding treatment due to the precipitation of CrN in nitriding layer, the corrosion resistance of the sample after plasma nitriding was higher than the one after nitrocarburizing.