While the achievement of size and form tolerances is already state of the art for grinding, there are hardly any industrial solutions to identify thermo-mechanical process loads such as grinding burn. A system was developed, presented, and tested, which allows for the first time the in-process measurement of Barkhausen noise to indicate changes of the boundary zone’s state using a novel kind of sensor. The system enables tactile and non-contact measurement at sampling rates of up to 10 ms. During investigations on hardened shafts of 100Cr6, relevant influences on the in-process Barkhausen noise were identified and evaluated. Furthermore, cause-effect relationships between microstructural effects and the Barkhausen noise were detected.