Patent ID: 8079266

Claim:
A device for material testing of a test object including at least one surface and at least electrically conducting and ferromagnetic parts comprising: at least one electromagnetic ultrasonic transducer including at least one magnet and at least one eddy current coil; and wherein the at least one eddy current coil has at least one electrical strip conductor disposed at or parallel to a surface area of a ferromagnetic or electrically conductive rolling member for rolling on the at least one surface of the test object, with the surface area and the rolling member rolling over the at least one surface, the at least one magnet is integrated in the rolling member and moves jointly with the rolling member relative to the at least one surface to cause a magnetic field from the at least one magnet to penetrate at least into one area of the test object which is in contact with the rolling member when the rolling member rolls over the at least one surface, and the rolling member is a disk or cylinder having a circumferential edge around which the at least one electrical strip conductor of the eddy current coil is curved, the rolling member has an axis of rotation about which the rolling member rotates when rolling on the surface of the test object, and the at least one magnet is a bar permanent magnet which is attached asymmetrically and is rotatable about the axis of rotation of the rolling member so that a mass center of gravity of the bar permanent magnet lies outside the axis of rotation and a magnetic pole of the bar permanent magnet continually faces the circumferential edge of the rolling member during rolling contact with the surface of the test object.