| 摘要 |
An object is to provide a high-strength steel sheet having excellent phosphatability and excellent corrosion resistance after electrodeposition coating has been performed, even in the case where the contents of Si and Mn are high and to provide a method for manufacturing the steel sheet. A method for manufacturing a high-strength steel sheet, the method including, when a steel sheet having a chemical composition containing, by mass%, C: 0.03% or more and 0.35% or less, Si: 0.01% or more and 0.50% or less, Mn: 3.6% or more and 8.0% or less, Al: 0.01% or more and 1.0% or less, P: 0.10% or less, S: 0.010% or less, and the balance being Fe and inevitable impurities is annealed by using a continuous annealing method, performing a heating process at a heating rate of 7°C/sec. or more in a temperature range in the annealing furnace of 450°C or higher and A°C or lower, controlling the maximum end-point temperature of a steel sheet in the annealing furnace to be 600°C or higher and 700°C or lower, controlling the traveling time of the steel sheet in a steel sheet temperature range of 600°C or higher and 700°C or lower to be 30 seconds or more and 10 minutes or less, and controlling the dew point of the atmosphere in a steel sheet temperature range of 600°C or higher and 700°C or lower to be -40°C or lower, where A: 500 ‰¤ A ‰¤ 600. |
