Detectability of Thermomechanical Surface Damages on Quenched and Tempered, Nitrided and Case-Hardened Steels by Barkhausen Noise Analysis

Magnetic Barkhausen noise analysis is an already industrially used method for the detection of grinding burn and offers several advantages over the established nital etching test with respect to objectivity, cost savings as well as occupational safety and environmental protection. Studies on the detectability of damages and influencing factors such as the condition of the surface zone prior to grinding have so far only existed in isolated cases and mostly limited to a few widely used case-hardened steels. For this reason, various steel grades used in particular in the aerospace sector were considered in this study. For one quenched and tempered, one nitrided and two case-hardened steels, the detectability of damages by means of Barkhausen noise and the influence of different heat treatment parameters were investigated. It was shown that the use of Barkhausen noise analysis is also possible on these steel grades and enables more reliable damage detection than nital etching.