METHOD FOR MANUFACTURING HOT-EXTRUDED SEAMLESS STEEL TUBE HAVING EXCELLENT INNER SURFACE QUALITY

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing a hot-extruded seamless steel tube having excellent inner surface quality. SOLUTION: In the method for manufacturing the hot-extruded seamless stainless steel tube having excellent inner surface quality, hot-extrusion is performed by setting the angleθof inclination of a die to be 10-50°from the perpendicular in the extruding rear end direction. In the method for manufacturing the hot-extruded seamless steel tube having excellent inner surface quality, the angleθof inclination is set to 20-50°. Unevenness of an inner surface of the steel tube is eliminated, and the quality can be improved. COPYRIGHT: (C)2005,JPO&NCIPI