METHOD FOR IMPROVING QUALITY OF INNER SURFACE OF HOT SEAMLESS STEEL TUBE AND MANDREL MILL

摘要

PURPOSE:To improve the quality of inner surface and to reduce the expense for repairing the inner surface. CONSTITUTION:A head 9 providing a high pressure water jetting nozzle is inserted into a tube stock 2 to be rolled. The oxide scale of the inner surface of the tube stock 2 to be rolled is removed by moving either one side or both sides of the head 9 and the tube stock 2 to be rolled in the axial direction of the tube stock. The tube stock 2 to be rolled that the oxide scale is removed is rolled with the mandrel mill 1.