Filing Information

Inventor(s)	Ralph W. Leonard ·
Assignee(s)	United States Steel Corporation ·  View assignee updates
Attorney/Agent(s)	Arthur J. Greif ·
Primary Examiner	Sadie L. Childs ·
Application Number	US6439157
Filing date	11/04/1982
Issue date	06/26/1984
Predicted expiration date	12/02/2001
U.S. Classifications	428/653  · 427/399  ·
International Classifications	B32B 1510  ·
Kind Code	A
International Classifications	427329;374.4;328;376.5;399;376.8;405;406;433;436;431 ·
Related U.S. Application Data	This application is a continuation-in-part of application Ser. No. 326,732, filed Dec. 2, 1981 and now abandoned.

Patent Family

Abstract

Hot-dip coated steel articles having a coating containing about 55% aluminum, 43% zinc, 2% silicon, are known to exhibit an optimum combination of general corrosion resistance, more durable than zinc coatings; while providing more galvanic protection to cut edges and areas of mechanical damage than hot-dip aluminum coatings. It has now been found that coatings containing 12 to 24% zinc, up to 4% silicon, balance aluminum, provide galvanic protection equal to or superior to such known coatings, while providing enhanced general corrosion resistance, approaching that of aluminum coatings.

Independent Claims | See all claims (16)

1. 1. In the method for producing corrosion-resistant coatings, metallurgically bonded to ferrous-base articles, which comprises dipping a clean surface of said article into a molten bath containing aluminum and zinc for a period at least sufficient to form an aluminum-zinc coating thereon with an interfacial alloy layer having a thickness greater than about 0.01 mils, said layer resulting from the reaction of the ferrous surface with the bath, removing the coated surface from said bath and cooling the molten layer adhering thereto,the improvement for producing a coating which provides a superior combination of general and sacrificial corrosion resistance, which comprises using a bath consisting essentially of 12 to 24% zinc, 0.3 to 4% silicon, 0.3 to 3.5% iron and the balance aluminum.
2. 6. In the method for producing corrosion-resistant coatings, metallurgically bonded to steel sheet, which comprises dipping a clean surface of said sheet into a molten bath containing aluminum and zinc for a period of 0.5 to 10 seconds and sufficient to form an aluminum-zinc coating thereon with an interfacial alloy layer having a thickness of 0.01 to 0.2 mils, said layer resulting from the reaction of the ferrous surface with the bath, removing the coated surface from said bath and cooling the molten layer adhering thereto,the improvement for producing a coating which provides a superior combination of general and sacrificial corrosion resistance, which comprises using a bath consisting essentially of 12 to 24% zinc, 0.3 to 4% silicon, 0.3 to 3.5% iron and the balance aluminum.
3. 11. In the method for producing corrosion-resistant coatings metallurgically bonded to ferrous-base articles, which comprises dipping a clean surface of said article into a molten bath containing aluminum and zinc for a period at least sufficient to form an interfacial layer having a thickness greater than about 0.01 mils, said layer resulting from the reaction of the ferrous surface with the bath, removing the coated surface from said bath and cooling the molten layer adhering thereto,the improvement for producing a coating which provides a superior combination of sacrificial and general corrosion resistance, which comprises using a bath consisting essentially of 12 to 18% zinc, less than 0.3% silicon, 0.3 to 3.5% iron, balance aluminum.