Detection of surface defects on continuously cast metal semi-products by generating and detecting eddy currents at the surface of the metal product

摘要

Detection of surface defects on a continuously cast metal semi-product uses a surface defect sensor for eddy currents with separated emitters and receivers. The sensor incorporates at least one line of at least three contiguous and controllable measuring cells. Each measuring cell is able to generate eddy currents at the surface of the metal product and, alternately, detect the eddy currents on the same surface. The method includes a stage of control of first and second cells of the same line, the first cell being controlled to generate the eddy currents at the surface of the metal product and the second cell being controlled to detect the eddy currents generated by the first and of which the circulation at the surface has been modified by the presence of surface defects. The first and second cells are separated from each other by at least one inactive measuring cell. An independent claim is also included for a system for the detection of surface defects in a continuously cast metal semi-product by this method.