| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high-strength steel sheet that exhibits excellent chemical convertibility and post-electrodeposition-coating corrosion resistance, even with a high Si content, and a manufacturing method therefor. <P>SOLUTION: When performing continuous annealing on a steel sheet that contains, by mass, 0.01 to 0.18% C, 0.4 to 2.0% Si, 1.0 to 3.0% Mn, 0.001 to 1.0% Al, 0.005 to 0.060% P, and at most 0.01% S, with the remainder comprising Fe and unavoidable impurities, during a heating process, the atmospheric dew point is set to be -40°C or lower and the temperature rising rate is set to be 7°C/s or more for the heating-furnace temperature range of 600°C to A°C (A: 650≤A≤780), and the atmospheric dew point is set to be -10°C or higher for the heating-furnace temperature range of >A°C and ≤B°C (B: 800≤B≤900). <P>COPYRIGHT: (C)2012,JPO&INPIT |
