HIGH-STRENGTH COLD-ROLLED STEEL SHEET HAVING EXCELLENT WORKABILITY AND IMPACT RESISTANCE, AND METHOD FOR MANUFACTURING SAME

摘要

A high-strength cold-rolled steel sheet having excellent ductility and stretch- flangeability, and a method for manufacturing the same are provided. The high-strength cold-rolled steel sheet having excellent workability and impact resistance comprises, by mass, 0.05-0.3% C, 0.3-2.5% Si, 0.5-3.5% Mn, 0.003-0.100% P, 0.02% or less S, 0.010-0.5% Al, with the balance being Fe and inevitable impurities, and has a structure comprising, by surface area, 20% or more ferrite, 10-60% tempered martensite and 0-10% martensite and, by volume, 3-15% residual austenite.