METHOD FOR IMPROVING SERVICE LIFE OF MANDREL BAR

摘要

PROBLEM TO BE SOLVED: To provide a method by which the service life of a mandrel bar is improved without bringing about the deterioration of the manufacturing efficiency and thickness accuracy of a seamless steel tube. SOLUTION: This method is a method by which the service life of the mandrel bar which is used for rolling with a mandrel mill is improved and which includes a first process for removing a material which is coagulated on the outer surface of the mandrel bar used for rolling and of which a tube stock is composed and a second process for forming an iron hydroxide film on the outer surface of the mandrel bar. COPYRIGHT: (C)2006,JPO&NCIPI