THIN STEEL SHEET SUPERIOR IN COLD DELAYED AGING PROPERTY AND BAKE HARDENING PROPERTY

摘要

PROBLEM TO BE SOLVED: To provide a thin cold-rolled steel sheet superior in cold delayed aging properties and bake hardening properties.;SOLUTION: The thin steel sheet superior in the cold delayed aging properties and the bake hardening properties comprises, by mass%, 0.001-0.2% C, 0.0001-0.2% N, 0.002-0.3% C+N, 0.001-0.1% Si, 0.01-1% Mn, 0.001-0.1% P, 0.05% or less S, 0.001-0.1% Al, 0.001-0.1% Ti, 0.001-0.1% Nb, and the balance Fe with unavoidable impurities, and comprises ultrafine precipitates with diameters of 1-10 nm therein, so as to be as dense as 1×10¹⁷/cm³ or higher. In addition, the thin steel sheet preferably contains, by mass%, one or more of 0.005-0.25% Mo, 0.005-1.0% Cr, and 0.005-1.0% W.;COPYRIGHT: (C)2003,JPO