The investigation of wear and corrosion behavior of plasma nitrided DIN 1.2210 cold work tool steel

Abstract

Plasma nitriding process has been widely used to enhance the surface hardness, fatigue strength, wear and corrosion resistance of alloy steels. In this study, the effects of plasma nitriding temperature and time on the microstructure, surface hardness, wear and corrosion resistance of quenched and tempered DIN 1.2210 cold work tool steel were investigated. In this regard, the specimens were plasma nitrided at temperatures of 450°C and 550°C for 6h and 500°C for 3, 6 and 9h with the gas composition of 30% N2 and 70% H2. Optical microscopy, X-ray diffractions (XRD) and micro-hardness measurements were used to determine the microstructure and surface hardness. The wear and corrosion tests were performed by means of the pin-on-disk and potentiostat devices, respectively. XRD results illustrated that the compound layer was consisted of nitrided phases such as ε: Fe3N and γ′: Fe4N in all of nitriding conditions and increasing nitriding temperature reduced the amount of ε phase while amount of γ′ phase increased. Increasing the nitriding time resulted in an increment in the amount of ε and γ′ phases. In addition, plasma nitriding resulted in a significant increase in the surface hardness, wear and corrosion resistance of steel.