Mathematical Model of Prediction of Nitrogen Pickup in Nitriding Process of Low Carbon Ferromanganese

Abstract

Low carbon ferromanganese was nitrided through gas-solid reaction. The nitriding process has been carried out on lab scale at temperature range 800°C–950°C at different nitrogen pressures. Temperature, time, and partial nitrogen pressure of nitriding process of fine low carbon ferromanganese were investigated. Nitrogen content, in weight percent, was more than 9%. MATLAB software was used to derive mathematical model to predict nitrogen content as a function of temperature and nitrogen pressure. According to derived model, nitrogen content can be calculated by the following equation: N content,wt.%=(-30.8882+0.0326*T)/(1+e-((P+0.0038*T-8.4155)/(3.6374-0.0018*T))), where, T is nitriding temperature in K and P is nitrogen pressure in bar. The experimental results are in good agreement with the predicted results. The results showed that nitrogen content, at steady state, is mainly depending on temperature and pressure of nitriding process. MATLAB is a good tool to make precision mathematical model.