METHOD AND EQUIPMENT FOR REMOVING DEFECT ON PLATE MATERIAL SURFACE FOR ELECTRIC WELDED TUBE WITH GROOVE IN INNER SURFACE

摘要

PROBLEM TO BE SOLVED: To reduce occurrence of a defective product and to improve a gurantee accuracy of the quality of a product by using a marking device of the defective position on a plate material to give the mark and cutting off the marked defective position. SOLUTION: An optical sensor 4 is arranged at the position in a reflecting direction after hitting projecting light onto the surface of the plate material 1, i.e., at the position in the lower part of a flood lamp 2. At the time of reflection by hitting the projecting light onto the surface of the plate material 1, the optical sensor 4 detects fine shadow caused by the reflecting light at the defective position of hole, flaw, defective shape, discoloring, etc., on the surface of the plate material 1. The sensor 4 and a recording device 5 are connected in order to record the detected result and the detected defective position over the whole length of travelling plate material is recorded in the recording device 5. By this method, since the defective position can be cut off, the development of the defective product is reduced and the gurantee accuracy to the quality of the product is improved.