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US4456663: Hot-dip aluminum-zinc coating method and product

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Filing Information

Inventor(s) Ralph W. Leonard ·
Assignee(s) United States Steel Corporation ·
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 CodeA
International Classifications 427329;374.4;328;376.5;399;376.8;405;406;433;436;431 ·
Related U.S. Application DataThis application is a continuation-in-part of application Ser. No. 326,732, filed Dec. 2, 1981 and now abandoned.
16 Claims, No Drawings


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.

References Cited

U.S. Patent Documents

Document NumberAssigneesInventorsIssue/Pub Date
US2986808 Schnedler Jun 1961
US3058206 GEN ELECTRIC Mets Oct 1962
US3343930 BETHLEHEM STEEL CORP Borillo et al. Sep 1967
US3393089 BETHLEHEM STEEL CORP Borzillo et al. Jul 1968
US3782909 BETHLEHEM STEEL CORP Cleary et al. Jan 1974
US3860438 BETHLEHEM STEEL CORP Shoemaker Jan 1975
US3952120 Bethlehem Steel Corporation Horton et al. Apr 1976
US4171392 Inland Steel Company Sievert et al. Oct 1979

Foreign Patent Documents

Document NumberAssigneesInventorsIssue/Pub Date
DE2627433SIEMENS AGMar 1936
DE2634135ZIRCONAL PROCESSES LTDOct 1936

Other Publications

Zoccola et al., ASTM STP 646, S. K. Coburn Ed. American Society for Testing & Materials, 1978, pp. 165-184.
Gittings et al., Trans. ASM, 1951, vol. 4, pp. 587-610.

Patent Family

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