SKEW ROLLING METHOD OF SEAMLESS TUBE

PURPOSE:To prevent rear end contraction by retreating a plug at the point of time of rolling the predetermined part on the rear end side in the rolling direction of a base stock in the skew rolling of seamless tube. CONSTITUTION:At the point of time when the base stock is rolled to the preliminarily determined part on the rear end side of the base stock by a piercer 10 or the like with a disk shoe, the plug 13 is retreated, the wall thickness in the rear end part of hollow bloom is thickened and the outside and inside diameters at the position of the plug 13 where the thickness is determined are enlarged. In this way, the rear end contraction of the hollow bloom in the skew rolling of seamless tube with a piercer, elongater, etc., can be prevented. This method is specially useful when manufacturing seamless tube of a high alloy steel contg. >=5% Cr and also available when manufacturing thin seamless tube of common steel.