Rolling control method, rolling control apparatus and control program for a mandrel mill, and a method of manufacturing a seamless tube or pipe

摘要

In a rolling control method for a mandrel mill M having a plurality of grooved rolls including a finishing stand #i by moving the rolling positions of first grooved rolls installed in the finishing stand outwards when rolling a pierced blank S in the finishing stand #i, when rolling the pierced blank in the closest upstream stand #(i-2) to the finishing stand 4i having the same roll-reducing directions, the rolling positions of second grooved rolls installed m the upstream stand #(i-2) are also moved outwards, thereby making it possible to accurately roll a pierced roll for the entire length of a portion such as the end portions to a desired wall thickness when manufacturing a seamless tube using the mandrel mill.