Electroplated corrosion resistant steels and method for manufacturing same

• US 4,407,900 A
• Filed: 10/08/1981
• Issued: 10/04/1983
• Est. Priority Date: 10/17/1980
• Status: Expired due to Fees

• Current Assignee: Klaus Schmidt
• Original Assignee: Klaus Schmidt
• Inventors: Iwai, Masatoshi, Kirihara, Shigeki
• Primary Examiner(s): Kaplan, G. L.
• Application Number:
  US06/309,782
• Time in Patent Office: 726 Days
• Field of Search: 204/43 Z, 204/41, 204/40, 428/659, 428/658
• US Class Current: 428/659
• CPC Class Codes: C25D 3/565 containing more than 50% by weight of zinc
• CPC Class Codes: C25D 5/14 two or more layers being of nickel or chromium, e.g. duplex or triplex layers
• CPC Class Codes: Y10T 428/12792 Zn-base component
• CPC Class Codes: Y10T 428/12799 Next to Fe-base component [e.g., galvanized]

Abstract

An electroplated corrosion resistant steel, having on a base steel a first plated layer of a Zn-Ni alloy containing 5-20% of Ni and a second electroplated layer of zinc containing 0.005-0.5% of Cr. A method for producing the high corrosion resistant steel material is also disclosed.

Claims

1. A steel material with a treated high corrosion resistant surface, comprising on a base steel a first plated layer of a Zn-Ni alloy consisting essentially of 5-20% of Ni and the balance Zn;

and a second electroplated layer consisting essentially of zinc containing 0.005-0.5% of Cr.

2. A steel material as defined in claim 1, wherein said first plated layer of the Zn-Ni alloy has a thickness greater than 1/20 of the total thickness of the two plated layers.

3. A steel material as defined in claim 1, wherein said second electroplated layer of Cr-containing zinc has a thickness greater than about 1 g/m².

4. A method for producing a steel material with a treated high corrosion resistant surface, comprising electroplating on said steel material a first layer of a Zn-Ni alloy consisting essentially of Zn and Ni in a first plating bath containing Zn and Ni wherein each concentration of Zn and Ni in said plating bath is over 20 g/l, respectively, and having a ratio of Zn concentration (g/l) to Ni concentration (g/l) in the range of 0.25-4, and electroplating on said first layer a second layer consisting essentially of Cr-containing zinc in a second electrogalvanizing bath with 0.1-10 g/l of Cr³⁺ and/or 0.05-0.5 g/l of Cr⁶⁺ content.

5. A method as defined in claim 4, wherein said first Zn-Ni alloy plating bath has a pH in the range of 1.5-3.5.

6. A method as defined in claim 4, wherein said first Zn-Ni alloy plating bath has a temperature in the range of 40°

-70°

C.

7. A method as defined in claim 4, wherein said second electrogalvanizing bath has a pH in the range of 2.5-3.5 when added with a Cr compound of Cr³⁺ and a pH in the range of 3.5-4.5 when added with a Cr compound of Cr⁶⁺.

8. A method as defined in claim 4, wherein said second electrogalvanizing bath has a temperature in the range of 40°

-70°

C.

9. A method as defined in claim 4, wherein said first Zn-Ni alloy plating bath has a temperature in the range of 50°

-60°

C.

10. A method as defined in claim 4, wherein said second electrogalvanizing bath has a temperature in the range of 50°

-60°

C.