Patent ID: 8717013

Claim:
A method of use of a device for detecting manufacture-related or operation-related damage sites in a test specimen made of ferromagnetic material, comprising the steps of: providing a test specimen made of ferromagnetic material; providing a device for detecting manufacture-related or operational-related damage sites in said test specimen, comprising a magnetization unit, which generates a constant magnetic field, wherein said magnetization unit has at least one yoke with width in the direction of a relative motion, said yoke having arms; a first sensor set back from said magnetization unit in the direction of relative motion, which first sensor detects defect sites on the basis of the influence of said defect sites on induced eddy currents; at least one second sensor, for measuring at least one member selected from the group consisting of induced eddy currents and magnetic leakage flux, disposed between said arms of said yoke of said magnetization unit; and at least one third sensor, which is set ahead of said magnetization unit in the direction of relative motion, for measuring at least one member selected from the group consisting of induced eddy currents and magnetic leakage flux; exposing said test specimen to said magnetic field generated by said magnetization unit in order to magnetize said test specimen; moving said magnetization unit and said test specimen relative to one another to induce eddy currents in said test specimen; utilizing said at least one second sensor to measure at least one member selected from the group consisting of the induced eddy currents and magnetic leakage flux; utilizing said at least one third sensor to measure at least one member selected from the group consisting of the induced eddy currents and magnetic leakage flux; and utilizing said first sensor to detect defect sites in said test specimen, based on the influence of said defect sites on the induced eddy currents.