Process for manufacturing electro-galvanized steel sheet excellent in paint adherence
AssigneeNippon Kokan Kabushiki Kaisha
InventorsKazuo Matsudo, Takeshi Adaniya, Masaru Ohmura, Masahiro Shoji, Tsutomu Watanabe
Life of this patent
Estimating the term…
Abstract
In an acidic zinc sulfate and iron sulfate electro-galvanizing bath, of which a pH value has been adjusted to under 1.5, containing iron from 20 to 90 wt. % relative to the total amount of metals capable of being electro-deposited in said acidic electro-galvanizing bath, a steel sheet is subjected to an electro-galvanizing treatment, with an electric current having a current density of from 10 to 40 A/dm.sup.2 to form on said steel sheet an electro-galvanized layer in a weight of from 1 to 50 g/m.sup.2, containing iron from 5 to 35 wt. % relative to the total weight of the electro-galvanized layer.
Claims2
In a process for manufacturing a galvanized steel sheet, which comprises electro-galvanizing a steel sheet in an acidic galvanizing bath to form a galvanized layer excellent in paint adherence on the surface of said steel sheet;
- the improvement characterized by comprising:
- electro-galvanizing a steel sheet in an acidic zinc sulfate and iron sulfate galvanizing bath, with a pH value adjusted up to 1.5, containing iron of from 20 to 90 wt.% relative to the total amount of metals capable of being deposited in said galvanizing bath, with an electric current having a current density of from 10 to 40 A/dm.sup.2, to form on the surface of said steel sheet a galvanized zinc-iron layer, containing iron of from 5 to 35 wt.% relative to the total amount of said galvanized layer in an amount of from 1 to 50 g/m.sup.2 per side of said steel sheet.
In a process for manufacturing a galvanized steel sheet, which comprises electro-galvanizing a steel sheet in an acidic galvanizing bath to form a galvanized layer excellent in paint adherence on the surface of said steel sheet;
- the improvement characterized by comprising:
- electro-galvanizing a steel sheet in an acidic zinc sulfate and iron sulfate galvanizing bath, with a pH value adjusted up to 1.5, and containing iron and at least one of nickel, chromium and copper in an amount of from 20 to 90 wt.% relative to the total amount of metals capable of being deposited in said acidic galvanizing bath, with an electric current at a current density of from 10 to 40 A/dm.sup.2, to form on the surface of said steel sheet a galvanized layer containing iron of from 5 to 35 wt.% and at least one of nickel, chromium and copper of from 0.01 to 10 wt.% relative to the total amount of said galvanized layer, in an amount of from 1 to 50 g/m.sup.2 per side of said steel sheet.
Dependencies are inferred from the claim text.