| 摘要 |
The purpose of the present invention is to provide a high-strength steel sheet having exceptional chemical conversion treatment properties and post-electrodeposition-coating corrosion resistance even when the Si or Mn content is high, as well as a method for manufacturing the high-strength steel sheet. A method for manufacturing a high-strength steel sheet comprising continuously annealing a steel sheet containing, by mass%, 0.03-0.35% of C, 0.01-0.50% of Si, 3.6-8.0% of Mn, 0.01-1.0% of Al, 0.10% or less of P, and 0.010% of S, the balance being Fe and unavoidable impurities. In the heating process during continuous annealing, the temperature increase rate is 7ºC/s or greater in a temperature zone in which the temperature inside the annealing furnace is 450ºC to AºC, the maximum temperature achieved by the steel sheet in the annealing furnace is 600-700ºC, the transit time of the steel sheet in a temperature zone in which the temperature of the steel sheet is 600-700ºC is 30 seconds to 10 minutes, and the dew point in an atmosphere having a temperature zone in which the temperature of the steel sheet is 600-700ºC is -40ºC or less. A is within a range of 500 to 600 inclusive. |
