High-strength cold-rolled steel sheet and plated steel sheet excellent in deep drawability, steel pipes excellent in workability, and production methods thereof

摘要

PPROBLEM TO BE SOLVED: To provide a steel sheet which has excellent deep drawability, to provide a steel tube which has excellent workability, and to provide their production methods. PSOLUTION: The high strength cold rolled steel sheet having excellent deep drawability has a composition comprising, by mass, 0.025 to 0.25% C, 0.001 to 3.0% Si, 0.01 to 3.0% Mn, 0.001 to 0.15% P, 0.05% S, 0.0005 to 0.010% N, 0.008% Al and 0.0005 to 0.010% B, and the balance iron with inevitable impurities, has a metallic structure comprising one or more kinds selected from bainite, austenite, martensite and pearlite by a volume ratio of 2%, and has a mean r value of 1.1. PCOPYRIGHT: (C)2004,JPO&NCIPI