"Apparatus and method for detecting the progress of an ablation process on the surface of a cold rolled and / or hot rolled steel"

Means for detecting a progress of an ablation process on the surface of a cold rolled and / or hot-rolled steel with a magnetometer and an operably coupled to the magnetometers evaluation unit, wherein the evaluation unit is configured to compare the value determined by the magnetometer with a threshold value of a is a measure of the progress of the removal process.