| 摘要 |
PROBLEM TO BE SOLVED: To provide a high strength steel sheet having excellent chemical treatment property and corrosion resistance after electrodeposition even when the content of Si or Mn is high, and a manufacturing method therefor.SOLUTION: There is provided a manufacturing method of a high strength steel sheet where a heating process is conducted with a temperature in a firing furnace: rate of temperature rise of 7°C/s or more in a temperature range of 450°C to A°C and steel sheet maximum arrival temperature in the firing furnace of 600°C to 700°C, steel passing time in the temperature range of 600°C to 700°C of a steel sheet temperature of 30 seconds to 10 minutes and a dew point in atmosphere of the temperature range of 600°C to 700°C of the steel sheet temperature of -40°C or less when the steel sheet containing, by mass%, C:0.03 to 0.35%, Si:0.01 to 0.50%, Mn:3.6 to 8.0%, Al:0.01 to 1.0%, P≤0.10%, S≤0.010% and the balance Fe with inevitable impurities is continuous fired. However A:500≤A≤600. |
