HIGH-STRENGTH GALVANNEALED SHEET STEELS HAVING EXCELLENT SURFACE QUALITIES AND POWDERING RESISTANCE ANDMETHOD FOR MANUFACTURING THE SAME

摘要

The present invention relates to a steel sheet comprising, by weight%, 0.1 to 0.3% of C, 1 to 2.5% of Si, 2.5 to 10% of Mn, 0.001 to 0.5% of sol.Al, 0.04% or less of P, Ti: (48/14) * [N] to 0.1%, Ni: 0.005 to 0.5%, Sb: 0.01 to 0.07% %, Nb: not more than 0.1, B: not more than 0.005%, the balance Fe and other unavoidable impurities, and the cold-rolled steel sheet are formed by hot-dip galvanizing and alloying to form an alloyed plated layer, A high-strength alloyed hot-dip galvanized steel sheet excellent in surface quality and powdering property in a plating layer with a standard deviation of iron (Fe) content at 2 points is within 3%.