Effect of Process Parameters on Gas Nitriding of Grey Cast Iron

Abstract

Gas nitriding process parameters have significant effects on the nitriding layer of material. In the present work, a series of gas nitriding experiments on pearlitic grey cast iron specimens were carried out at different temperatures. To study the influence of nitriding process parameters on the nitriding layer, the numerical simulations of nitriding processing are performed, which take into account the threshold value of nitriding potential. The results show that the numerical simulations, incorporating the nitriding potential’s threshold value, can accurately predict the case depth and nitrogen concentration profile. The nitriding layer increases with increasing nitriding time and temperature, whereas the nitrogen concentration on the surface decreases with increasing temperature. Besides, the results also reveal that the nitriding potential nearly has no effect on the case depth, whereas it has great influence on nitrogen concentration on the surface and chemical composition of the compound layer.