High-strength hot-dip galvannealed steel sheet and method for producing same
AssigneeJfe Steel Corporation
InventorsSatoshi Maeda, Yoshiyasu Kawasaki, Yusuke Fushiwaki, Mai Aoyama
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Abstract
A method for producing a high-strength hot-dip galvannealed steel sheet, in which a high-strength steel sheet is used as a base material, includes a rolling step (x) of rolling a hot-dip galvannealed steel sheet with a coating layer having an Fe concentration of 8% to 17% by mass, and a heat treatment step (y) of heating the coated steel sheet which has been subjected to the rolling step (x) under the conditions satisfying the following formulae (1) and (2): (273+T)×(20+2×log10(t))≥8000 (1) 40≤T≤160 (2) where T: heating temperature (° C.) of the coated steel sheet, and t: holding time (hr) at the heating temperature T.
Claims15
A method for producing a high-strength hot-dip galvannealed steel sheet, in which a high-strength steel sheet is used as a base material, the method comprising:
- a rolling step (x) of rolling a hot-dip galvannealed steel sheet with a coating layer having an Fe concentration of 8% to 17% by mass;
- and
- a heat treatment step (y) of heating the coated steel sheet which has been subjected to the rolling step (x) under the conditions satisfying the following formulae (1) and (3):
- (273+T)×(20+2×log10(t))≥8000 (1)
- 60≤T≤120 (3)
- where T:
- heating temperature (° C.) of the coated steel sheet, and t:
- holding time (hr) at the heating temperature T.
Dependencies are inferred from the claim text.