MANUFACTURE OF LARGE DIAMETER SQUARE STEEL TUBE

摘要

PURPOSE:To accurately form a large diameter square steel tube with a low forming load. CONSTITUTION:A large diameter square steel tube 5 is manufactured as follows: the whole surface of a circular large diameter welded steel tube 1 manufactured by welding butt parts where are formed into a circular shape is heated by induction heating up to 500-1000 deg.C then formed by forming rolls 4 into a square shape. Further, in this manufacture, a temp. rising speed is regulated to >=100 deg.C/min and a heating time is regulated to <=10min.