Method for producing zinc coated steel sheet
AssigneeNKK Corporation
InventorsMasaki Abe, Satoru Ando, Toyofumi Watanabe, Yukimitsu Shiohara
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Abstract
A method for producing zinc coated steel sheet comprises the steps of: forming a Ni--P alloy coating layer containing P of 8 to 15 wt. % on at least one surface of a steel sheet; heat-treating the steel sheet coated with the alloy layer in a non-oxidizing atmosphere to form an Fe--Ni--P diffused alloy layer at an interface of the steel sheet and the alloy coating layer; and zinc coating the steel sheet coated with the diffused alloy layer to form a zinc coating layer.
Claims56
A method for producing a zinc coated steel sheet, comprising the steps of:
- forming a Ni--P alloy coating layer containing P of 8 to 15 wt. % on at least one surface of a steel sheet;
- heat-treating the steel sheet coated with the alloy coating layer in a non-oxidizing atmosphere at a maximum temperature of 500.degree. to 800.degree. C. and a holding time of 1 to 30 seconds to form an Fe--Ni--P diffused alloy layer at an interface of the steel sheet and the alloy coating layer;
- and
- hot-dip galvanizing the steel sheet coated with the diffused alloy layer to form a hot dip galvanized coating layer.
A method for producing a zinc coated steel sheet, comprising the steps of:
- forming a Ni--P alloy coating layer containing P of 8 to 15 wt. % on at least one surface of a steel sheet;
- heat-treating the steel sheet coated with the alloy layer in a non-oxidizing atmosphere at a maximum temperature of 500.degree. to 800.degree. C. and a holding time of 1 to 120 seconds to form an Fe--Ni--P diffused alloy layer at an interface of the steel sheet and the alloy coating layer;
- and
- zinc-electroplating the steel sheet coated with the diffused alloy layer to form a zinc electroplated layer.
A method for producing a zinc coated steel sheet, comprising the steps of:
- forming a Ni--P alloy coating layer containing P of 8 to 15 wt. % on at least one surface of a steel sheet;
- cold-rolling the steel sheet coated with the alloy coating layer;
- heat-treating the cold-rolled steel sheet in a non-oxidizing atmosphere at a maximum temperature of 500.degree. to 850.degree. C. and a holding time of 1 to 120 seconds to form an Fe--Ni--P diffused alloy layer at an interface of the steel sheet and the alloy coating layer;
- and
- zinc-coating the steel sheet coated with the diffused alloy layer to form a zinc coating layer.
Dependencies are inferred from the claim text.