ALLOYED HOT-DIP GALVANIZED STEEL SHEET HAVING EXCELLENT FORMABILITY AND POST-ADHESION DETACHMENT RES

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The galvannealed steel sheet includes : a steel sheet; a galvannealed layer which is formed on at least one surface of the steel sheet and contains includes an amount equal to or more than 0.05 mass% and equal to or less than 0.5 mass% of Al, an amount equal to or more than 6 mass% and equal to or less than 12 mass% of Fe, and optionally an amount equal to or less than 2 mass% of at least one kind of Pb, Sb, Si, Fe, Sn, Mg, Mn, Ni, Cr, Co, Ca, Cu, Li, Ti, Be, Bi, and rare earth elements as needed, and the balance composed of Zn and inevitable impurities; and a mixed layer which is formed on a surface of the galvannealed layer and includes a composite oxide of Mn, Zn, and P and an aqueous P compound, wherein the composite oxide contains includes an amount equal to or more than 0.1 mg/m2 and equal to or less than 100 mg/m2 of Mn, an amount equal to or more than 1 mg/m2 and equal to or less than 100 mg/m2 of P, and Zn, and has so that a P/Mn ratio is of equal to or higher than 0.3 and equal to or lower than 50, and wherein the total size of an area of the mixed layer in which an attached amount of Pamount of P adhesionP attached is equal to or more than 20 mg/m2 is equal to or higher than 20% and equal to or lower than 80% of a surface area of the mixed layer.