Patent ID: 8460481

Claim:
A high-strength cold rolled steel sheet having very good balance between hole expansibility and ductility, and also excellent in fatigue resistance, characterized in: comprising, in mass %, C: 0.05% to 0.20%, Si: 0.3 to 2.0%, Mn: 1.3 to 2.6%, P: 0.001 to 0.03%, S: 0.0001 to 0.01%, Al: 2.0% or less, N: 0.0005 to 0.0100%, O: 0.0005 to 0.007%, and a balance of iron and unavoidable impurities; and having a steel sheet structure composed mainly of, in vol %, ferrite: greater than 50% and hard structure: 5% or greater, wherein said hard structure is composed of bainite, martensite, and residual austenite, and 50% or greater, in vol %, of the entire hard structure has a crystal orientation difference between some ferrite adjacent to hard structure and the hard structure of less than 9°, and a maximum tensile strength of 540 MPa or greater, wherein said crystal structure orientation difference is a value composed of both a [1-1-1] crystal orientation difference and a crystal orientation difference in the direction normal to the (110) plane.