Effect of post-treated low-temperature plasma nitriding on the wear and corrosion resistance of 316L stainless steel manufactured by laser powder-bed fusion

Abstract

Due to the limited wear and corrosion properties of the austenitic stainless steel AISI 316 L, some applications require the benefits of nitriding. The aim of this work was to investigate whether the same positive effect of nitriding could be obtained for 316 L that was additive manufactured using the laser powder-bed fusion process and further solution treated at 1060 °C for 30 min, low-temperature plasma nitrided at 430 °C or both. This study was designed to better understand the additive-manufactured and solution-treated microstructures as well as developing a nitride and a diffusion layer. The comparison of the wear and corrosion resistance, the microhardness and the microstructure changes of the additive-manufactured steel in different post-treated conditions with a commercial steel was carried out. It was found that the post-treated low-temperature plasma nitriding improves the wear and corrosion resistance of the additive-manufactured samples. The obtained values are similar to the values of conventionally fabricated and nitrided 316 L. The solution treating itself (without further nitriding) did not have any significant impact on these properties. It was possible to explain the microstructure at the nano level as well as correlating the wear and corrosion properties.