Application of design of experiments in gas nitriding of steels

Abstract

This work deals with the application of Design of Experiments (DoE) method in Gas Nitriding surface thermochemical treatment of steels. The main contribution herein lies in modeling the Gas Nitriding of steels in order to compare factors effects on the Nitrided Layer (NL) depth as well as optimizing this latter for a certain value, without having to perform expensive and exhaustive experimental procedures. By applying the technique of Linear Regression on Gas Nitriding experimental data of the steel 35CrMo12, a full factorial design of three factors with three levels was created. The model was then successfully validated through statistical analysis. The results revealed that the nitriding temperature has the greatest influence on the NL depth, followed by potential, and then time. The promising part of employing Design of Experiments is establishing a mathematical equation of NL depth as function of temperature, time and potential, as this would optimize and facilitate experimental procedures. It is envisaged that this work would be the main driver for several research projects in Gas Nitriding modeling utilizing Design of Experiments.