High strength galvanized steel sheet having excellent surface qualities, plating adhesion, and formability, and method for manufacturing same

A method for a high strength galvanized steel sheet having excellent surface qualities, plating adhesion, and formability, the method comprising:

• forming a steel slab comprising 0.1-0.3 wt % of C, 1-2.5 wt % of Si, 2.5-8 wt % of Mn, 0.001-0.5 wt % of sol. Al, 0.04 wt % or less of P, 0.015 wt % or less of S, 0.02 wt % or less of N (excluding 0 wt %), 0.1-0.7 wt % of Cr, 0.1 wt % or less of Mo, (48/14)*[N] to 0.1 wt % of Ti, 0.005-0.5 wt % of Ni, 0.01-0.07 wt % of Sb, 0.1 wt % or less of Nb, and 0.005 wt % or less of B, with the remainder being Fe and other inevitable impurities;
• reheating the steel slab at a temperature of 1100-1300° C.;
• ultimately hot rolling the re-heated steel slab at a Ar3 transformation point or higher;
• coiling the hot rolled steel sheet at a temperature of 700° C. or lower;
• pickling and then cold rolling the coiled steel sheet;
• recrystallization annealing the cold rolled steel sheet at a dew point temperature of −60° C. to −20° C. and at a temperature of 750-950° C. for 5 to 120 seconds;
• cooling the annealed cold-rolled steel sheet to 200-600° C. at an average cooling rate of 2-150° C./s;
• reheating or cooling the cooled steel sheet to a temperature of (galvanizing bath temperature−20° C.) to (galvanizing bath temperature+100° C.);
• and
• plating the reheated or cooled steel sheet by dipping in a galvanizing bath maintained at a temperature of 450-500° C.