Case Depth Evaluation of Induction Hardened Steel Using Barkhausen Noise Technique

Abstract

Barkhausen noise (BHN) measurement is one of electromagnetic testing methods that is suitable for ferromagnetic materials. It has a sensitivity to different material properties such as microstructure, composition, residue stress, hardness, etc. which can also be used to determine the hardness case depth of a hardened layer. The measurement is intriguing because of its time and cost-effectiveness. The aim of this work was to study and select a suitable method to evaluate and predict the hardness case depth of induction hardened S50C steel based on Barkhausen noise measurement. Signal processing of BHN signal was performed and extracted features were validated with the actual hardness case depth according to the destructive method of Vickers hardness and metallography in order to achieve the most accurate hardness case depth evaluation model. The results showed that the hardness case depth prediction model could be used to indicate the hardness case depth of induction hardened steel significantly at the correlation coefficient (R) of 0.97 and root mean squares error of estimation (RMSEE) of 3.56%.