ELECTROMAGNETO OSCILLATION HEAD FOR CRACK DETECTION OF METAL EDDY CURRENT

摘要

PURPOSE:To enable accurate inspection with small size, by providing pin shape core for detection winding the detection pin coil, and implanting a number of pin shape cores on the end surface of permanent magnet incorporated at the end of external circumference of the coil. CONSTITUTION:AC current flows to the pin shape core 2 for detection winding the detection pin coil 3 at the center of the holders 4, 5 before and after and contained inside the oscillation head 1. Further, the ring permanent magnet 8 is incorporated in the end of external circumference of the pin coil 3 and a number of pin shape cores 9 are implanted at the end surface in circular shape. The magnetic flux from the cores 9 penetrates in straight line from the sharp tip concentratingly and with repulsion each other to completely magnetize the inspected material to the deep part. Further, the AC magnetic field by the pin shape core 2 for detection is concentratedly penetrated from the tip, then the skin effect of inspected material is not subjected and it penetrates to the deep part of the inspected material, enabling to produce eddy current internally. Accordingly, the crack detection for ferromagnetic substance can be made with a small voltage, small sized and light weight unit.