| 摘要 |
PROBLEM TO BE SOLVED: To provide a working method where, in a thin steel sheet having the tensile strength of≥590 MPa, the crack resistance of the end parts worked by blanking or cutting is improved, to provide a high strength thin steel sheet, and to provide a component composed thereof. SOLUTION: In the working method for a high strength steel thin sheet having excellent crack resistance, when a thin steel sheet having the tensile strength of≥590 MPa is subjected to blanking or cutting, using a cutting blade having a level difference part which is continuously reduced by 0.01 to 3.0 mm than the radius of curvature or width of the blade heel from the blade heel toward the direction of the end parts in the blade edge, and whose height lies within the range of 1/2 of the sheet thickness in the tin steel sheet to 100 nm, the blanking or cutting is performed. By this working method, the high strength steel thin sheet in which the residual stress in the end faces worked by blanking or cutting is the tensile stress of≤500 MPa or the residual stress of compression can be obtained. COPYRIGHT: (C)2007,JPO&INPIT
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