公开(公告)号：BRPI0607805A2

公开(公告)日：2009-06-13

申请号：BRPI0607805

申请日：2006-02-22

Applicant: SUMITOMO METAL IND

Inventor： NAKAIKE KOUJI ,  HIDAKA TAKAMICHI ,  IIDA SUMIO ,  KUSUDA HIROKI ,  SAKIYAMA MASAMI

IPC: B21B25/04 ,  B21B17/02

Abstract: A seamless tube is manufactured while effectively suppressing the occurrence of carburization in the seamless tube without interfering with operations. A seamless tube is manufactured by a step of washing at least a portion of a conveyor installed in a conveying step of a mandrel bar B which is situated from a lubricant applying device 7 to the entrance of a mandrel mill 8, a step of washing, on the upstream side of the lubricant applying device 7, a mandrel bar B which was used for elongation rolling, and a step of applying a non-graphite-based lubricant to the mandrel bar B with the lubricant applying device 7, wherein the conveyor and the mandrel bar B are each washed such that the amount of graphite C2 (g/m 2 ) adhering to the surface of the mandrel bar B before it is provided to elongation rolling and the amount of carbon C1 (g/m 2 ) contained in the organic binder of the applied lubricant satisfy Equation 1: 0.08 x C1 + 0.05 x C2 ‰ 3 and Equation 2: 3 ‰ C1 + C2 ‰ 50.