Characterization of Plasma Nitrided X32CrMoV33 Die Steel

Abstract

In this study, nitriding behavior of plasma nitrided X32CrMoV33 die steel was investigated. Nitriding process was carried out at temperatures of 450, 500, and 550 degrees C for treatment time in the range of 2-32h. Depending on nitriding temperature and time, the thickness of compound layer ranged from 2 mu m to 15 mu m. The presence of '-Fe4N, epsilon-Fe2-3N, -Fe, and Cr2N phases formed in the compound layer was confirmed by XRD analysis. Using cross-sectional samples and a microhardness indenter, hardness depth profiles were also obtained; it was found that the hardness of compound layer was over 1000HV. Kinetic studies revealed that the effective diffusion coefficients for plasma nitrided X32CrMoV33 are approximately 40.3x10-14, 99.2x10-14, and 427x10-14m2s-1 for 450, 500, and 550 degrees C process temperatures, respectively. The activation energy for plasma nitrided X32CrMoV33 steel is 118.77kJ mol-1.