Effects of DC plasma nitriding parameters on properties of DIN 1.2344 low alloy steel

The aim of this paper is optimizing of parameters can be affected to depth of nitrided layer for improving the corrosion resistance of DIN 1.2344 low alloy steel by plasma nitriding.In this study, DIN 1.2344 low alloy steel samples were plasma nitrided at 3 level temperatures (450, 500 and 550℃), 3 level time (2, 4, 6 hour) and in 2 level gas compositions (25%N2-75%H2 and 75%N2-25%H2). Diffusion zone was determined by optical microscopy. Phases formed in these layers were studied by X-ray diffraction method. The XRD pattern reveals that all specimens consist Fe3N, Fe2N and Cr2N phases.Results have shown that depth of diffusion zone increases byincreasing gas compositions from 25% N2 to 75% N2. In addition, thickness of this layer have increased by increasing temperature from 450℃ to 550℃, but It seems that by increasing nitriding time of 2 to 4 hour the depth of the white layer increased but by increasing to 6 hour the depth of this layer decreased sligthly. The optimun condition for plasma nitriding of DIN 1.2344 is 550℃, 4h and 75% N2.

Keywords:

DIN 1.2344 , Microhardness , Diffusion zone , Optimum