GALVANNEALED STEEL SHEET

摘要

PROBLEM TO BE SOLVED: To provide a galvannealed steel sheet having excellent sliding characteristics at press forming and also excellent chemical treatment properties. SOLUTION: In the galvannealed steel sheet; an iron-zinc alloy plating layer is provided to at least one side of a steel sheet; the surface of the above plating layer has a flat zone; an oxide layer of >=10 nm thickness is formed on the flat zone; and the ratio (atomic %) between Zn and Al in the surface layer of the above flat zone is made to 2.0-8.0. The area ratio of the above flat zone in the surface of the above iron-zinc alloy plating is made to 20-80%.