MANUFACTURE OF CLAD STEEL TUBE

摘要

PROBLEM TO BE SOLVED: To reduce thickness deviation of a metallic internal tube in the manufacture of a clad steel tube with a press roll piercer. SOLUTION: When the clad steel tube is manufactured by inserting a metallic internal tube into the through hole which is provided on a billet having a rectangular cross section and over the entire length of the billet and rolling the billet that the boundary part between the billet and the metallic internal tube is joined at least at the end face of a side which is bitten with a rolling mill with the press roll piercer, the ratio Dp/Din of the diameter Dp of the plug of the piercer to the inside diameter Din of the metallic internal tube satisfies 1.4<=Dp/Din<=1.7.