Evaluation of wear-induced material loss in case-hardened steel

Case-hardened steels are frequently used in high-wear applications where friction between moving parts will slowly lead to erosion of the case. It is important to be able to characterize the case loss so that components can be replaced prior to failure. Results from previous and current studies indicate that it is possible to determine case depth using a combination of techniques including pulsed eddy current (PEC) and magnetic Barkhausen measurements. The challenges in determining case erosion are twofold: Firstly, the action of friction on a component will modify the near-surface microstructure, and secondly, the hardness depth profile will be very different to that of a newly hardened component. Despite these complications, we will show that it is possible, using a combination of eddy-current and magnetic techniques, to determine wear-induced material loss. We report here on measurements made after the multi-stage removal of material from the surface of a case-hardened steel disc and examine possibilities for a practical implementation of the measurement procedure.--This work was supported by the NSF Industry/University Cooperative Research program