HIGH-STRENGTH STEEL SHEET AND HIGH-STRENGTH GALVANIZED STEEL SHEET EXCELLENT IN SHAPE FIXABILITY,AND MANUFACTURING METHOD THEREOF

摘要

The present invention provides a high-strength steel sheet excellent in shape fixability. The high-strength steel sheet contains C, Si, Mn, P, S, Al, N, and O with predetermined contents, in which a retained austenite phase of 5 to 20% in volume fraction is contained, an amount of solid-solution C contained in the retained austenite phase is 0.80 to 1.00% in mass%, W Si³ is 1.10 times or more W Si* , W Mn³ is 1.10 times or more W Mn* , and when a frequency distribution is measured with respect to a sum of a ratio between W Si and W Si* and a ratio between W Al and W Al* , a mode value of the frequency distribution is 1.95 to 2.05, and a kurtosis is 2.00 or more.