| 摘要 |
Provided is a high-strength steel sheet having excellent shape-retaining properties, which contains predetermined quantities of C, Si, Mn, P, S, Al, N, and O, and contains a residual austenite phase of between 5% and 20% by volume fraction in a range between 1/8 and 3/8 of the thickness of the steel sheet. The quantity of solid solution C contained in the residual austenite phase is between 0.80% and 1.00% by mass, the quantity of solid solution Si (WSi γ) is 1.10 or more times the average Si quantity (WSi*), and the quantity of solid solution Mn (WMn γ) is 1.10 or more times the average Mn quantity (WMn*). When the frequency distribution is measured with respect to the sum of the ratio of the measured Si value (WSi) to the average Si quantity (WSi*) and the ratio of the measured Al value (WAl) to the average Al quantity (WAl*) at a plurality of measurement areas having a diameter of 1 μm or less in the range between 1/8 and 3/8 of the thickness of the steel sheet, the mode value of the frequency distribution is between 1.95 and 2.05 and the kurtosis is at least 2.00. |
