Process Parameters Optimization of Plasma Nitriding Depth of 1Cr11Ni2W2MoV Stainless Steel: Experimental and Simulation Studies

Using 1Cr11Ni2W2MoV stainless steel as the matrix material, the process parameter optimization of plasma nitriding depth was studied through experiments and numerical simulation calculations. In experimental research, two nitriding process parameters were tested to estimate the value of temperature and time. The microstructure exhibits an obvious nitrided layer composed by solid nitrogen atom α-Fe phase with a small amount of CrN and Fe4N phases. Based on the experimental results, four factors—nitriding time, nitriding temperature, atmospheric ratio, and nitriding pressure—were simulated by numerical simulation accompanied with orthogonal experimental design method. The results show that the trend in factors affecting the depth of the nitrided layer are: nitriding time > nitriding temperature > atmospheric ratio > nitriding pressure. The optimal process parameters for producing a maximum nitriding depth are nitriding temperature of 560°C with 16 h under 300 Pa nitriding pressure and atmospheric ratio 20%. An empirical formula was fitted for the relationship between the depth of the nitriding layer and the nitriding temperature and time: h2=3.812×109·e-11614/T·t\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$h^{{2}} = {3}{\text{.812}} \times {10}^{{9}} \cdot e^{{ - {11614/}T}} \cdot t$$\end{document}. Thus, this study opens an avenue to optimize plasma nitriding designing in stainless steel.