| 摘要 |
PROBLEM TO BE SOLVED: To provide a high strength cold rolled steel sheet having excellent bendability and a tensile strength of ≥1,180 MPa. SOLUTION: The high strength cold rolled steel sheet having excellent bendability has a componential composition containing, by mass, 0.10 to 0.15% C, 1.0 to 2.0% Si, 2.0 to 3.0% Mn, ≤0.030% P, ≤0.0050% S, 0.005 to 0.1% Al, ≤0.01% N, 0.005 to 0.050% Ti and 0.0001 to 0.0050% B, and has a structure including, by volume fraction, a bainite phase of 50 to 70%, a ferrite phase of 20 to 40%, a martensite phase of 1 to 10% and a retained austenite phase of ≤5%. COPYRIGHT: (C)2011,JPO&INPIT |
