Abstract: The invention relates to a mobile carrier system for at least one sensor element for testing test objects having convex surfaces. The system is provided for testing test objects that are at least made of ferromagnetic material. For this purpose, two first rollers are attached to a frame, the rotational axes of which are oriented parallel to each other and at a distance from each other. The distance of the two first rollers can be varied, and one of the two first rollers is attached to a carriage, which can be moved perpendicularly to the rotational axes of the two first. rollers. A drive for raising and lowering the first rollers is present on the two first rollers. Two pairs of second rollers are attached to the frame between the two first rollers. At least one pair of the second rollers comprises a rotary drive.

Abstract: The present invention relates to methods for non-destructive quantitative determination of the internal microstresses of type II and/or III which are based on subtraction of the maximum values of the load stress dependency of the maximum Barkhausen noise amplitudes on a test piece before and after hardening of the test piece in specific thermal hardening states. The present invention hence enables independent determination of the internal microstress of type II or III, simultaneous and resolved determination of the internal microstresses of type II and III and also determination of the sum of both types of internal microstresses.