| 摘要 |
<p>PURPOSE: A high-strength extremely low carbon steel sheet having excellent surface properties, a galvanized steel sheet and a manufacturing method thereof are provided to control the ratio of Si and Mn and the annealing temperature and dew point temperature appropriately. CONSTITUTION: A high-strength extremely low carbon steel sheet having excellent surface properties contains C of 0.001 to 0.005 weight%, Si of 0.1 to 1.5 weight%, Mn of 0.1 to 2.5 weight%, P of 0.01 to 0.1 weight%, Al of 0.01 to 0.07 weight%, Ti of 0.001 to 0.05 weight%, Nb of 0.001 to 0.05 weight%, B of 0.001 weight%, a remnant Fe and other impurities. The ratio of Si and Mn is 0.25 to 0.75.</p> |
