COLD ROLLED STEEL SHEET EXCELLENT IN BALANCE AMONG BAKING HARDENABILITY, DUCTILITY, AND NATURAL AGING CHARACTERISTIC AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To provide a cold rolled steel sheet free from problems of deteriora tion in surface characteristic and shape, surface roughing, etc., and excellent in a balance among baking hardenability, ductility, and natural aging characteris tic and its production. ;SOLUTION: This cold rolled steel sheet has a composition consisting of, by weight, 0.001-0.008% C, ≤0.3% Si, ≤1.5% Mn, ≤0.1% P, ≤0.015% S, ≤0.1% Al, ≤0.005% N, 0.003-0.06% Nb, 0.004-0.14% V, and the balance essentially Fe and satisfying inequalities 0.0002≤C-(12/93)Nb≤0.002(wt.%) and V≥0.55Nb+ 0.001(wt.%).;COPYRIGHT: (C)1997,JPO