Is superior in hydroforming process characteristic, possesses strain aging characteristic the electric resistance welded tube null

摘要

PROBLEM TO BE SOLVED: To provide an electric resistance welded steel tube excellent in formability at hydroforming and having strain aging characteristic. ;SOLUTION: A hot rolled or cold rolled hoop stock, which has a composition consisting of 0.01-0.05% C, ≤1.0% Si, ≤3.0% Mn, ≤0.15% P, ≤0.015% S, ≤0.04% Al, 0.005-0.02% (and ≥0.003% in a state of solid solution) of N and the balance Fe with inevitable impurities and containing, if necessary, at least one kind selected from 0.005-0.040% Nb, 0.005-0.50% Ti, 0.005-0.020% B, 0.02-1.5% Cu, 0.02-1.0% Ni, 0.02-1.0% Cr, 0.02-1.0% Mo, 0.0020-0.02% Ca and 0.0020-0.02% REM, is formed into cylindrical shape and the resultant seam is subjected to electric resistance welding, followed by sizing at 0.3-10% drawing rate of outer peripheral length.;COPYRIGHT: (C)2001,JPO