Method of manufacturing a small steel plate variation of yield stress and residual stress

摘要

PPROBLEM TO BE SOLVED: To provide a steel sheet whose characteristic distribution such as yield stress and residual stress is controlled. PSOLUTION: The steel sheet which is as-rolled or acceleratingly cooled and straightened so that the absolute value of the residual stress parameter η which is defined by formula (1) is ≤ 3.0 MPa when cutting at least one part from the steel sheet and also the variation of the ferritic grain diameter of the steel sheet is within the range of ( the average value in the measured region ± 1.5 μm ). Where, the area of the whole steel sheet is expressed by S (mmSP2/SP), the area of the minute region by s (mmSP2/SP), the value of the residual stress in the longitudinal direction of the steel sheet or the residual stress in the width direction in the minute region by σ (MPa) and the corrected total cutting region by Ω (mmSP2/SP). PCOPYRIGHT: (C)2005,JPO&NCIPI