| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a high strength cold rolled steel sheet and a high strength galvanized steel sheet which are inhibited from generating yield point elongation while having high ductility in a strength level of 440 MPa or more and less than 590 MPa without remarkable increase of manufacturing cost and alloy cost.SOLUTION: A high strength cold rolled steel sheet has a predetermined composition, a structure containing ferrite of, by a volume fraction, 85% or more, and a second phase of, by a volume fraction, 15% or less, and a tensile strength of 440 MPa or more and less than 590 MPa, wherein the second phase contains martensite of, by a volume fraction, 1% or more and less than 8%, and retained austenite of, by a volume fraction, 3% or more and less than 10%, a volume fraction of bainite being 1% or more and 5% or less, a volume fraction of pearlite being 0% or more and less than 2%, and a total volume fraction of the bainite and the pearlite being below the martensite volume fraction. |
