Method for coating a metal strip

• US 5,695,822 A
• Filed: 02/20/1996
• Issued: 12/09/1997
• Est. Priority Date: 04/05/1993
• Status: Expired due to Term

• Current Assignee: Revere Copper Products, Inc.
• Original Assignee: The Louis Berkman Company
• Inventors: Zamanzadeh, Mehrooz, Carey, Jay F. II
• Primary Examiner(s): UTECH, BENJAMIN L
• Application Number:
  US08/604,078
• Time in Patent Office: 658 Days
• Field of Search: 427/329, 427/331, 427/406, 427/433, 427/436
• US Class Current: 427/329
• CPC Class Codes: B32B 15/01 all layers being exclusively metallic making layered metal workpieces by pressure cladding B23K20/22; making coatings with a metallic material characterised by its composition C23C30/00
• CPC Class Codes: B32B 15/013 one layer being formed of an iron alloy or steel, another layer being formed of a metal other than iron or aluminium
• CPC Class Codes: C22C 13/00 Alloys based on tin
• CPC Class Codes: C22C 18/00 Alloys based on zinc
• CPC Class Codes: C23C 2/06 Zinc or cadmium or alloys based thereon
• CPC Class Codes: C23C 2/08 Tin or alloys based thereon
• CPC Class Codes: C23C 28/02 only coatings only including layers of metallic material
• CPC Class Codes: C23C 28/021 including at least one metal alloy layer
• CPC Class Codes: C23C 30/00 Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process C23C26/00, C23C28/00 take precedence
• CPC Class Codes: Y10S 428/939 Molten or fused coating
• CPC Class Codes: Y10T 428/12708 Sn-base component
• CPC Class Codes: Y10T 428/12715 Next to Group IB metal-base component
• CPC Class Codes: Y10T 428/12722 Next to Group VIII metal-base component
• CPC Class Codes: Y10T 428/12792 Zn-base component
• CPC Class Codes: Y10T 428/12799 Next to Fe-base component [e.g., galvanized]

Abstract

A corrosion-resistant metal strip and method for making the same which is essentially lead free and is not highly reflective. The coating on the metal strip is a two-phase metallic coating comprised of tin and zinc and a very low weight percentage of lead. The coating alloy may also include antimony, bismuth and copper to improve the coating process and/or improve the properties of the tin and zinc coating. A metal layer may also applied to the surface of the metal strip prior to applying the metallic alloy coating.

Claims

1. A method of producing a coated metal strip having corrosion-resistant properties comprising the steps of:

(a) providing a metal strip; and

,

(b) coating said metal strip with a corrosion-resistant alloy by passing said metal strip through a molten bath of said corrosion-resistant alloy such that the residence time of said metal strip in said molten bath is sufficient to deposit a layer of said alloy on the surface of said metal strip, said corrosion-resistant alloy comprising tin, zinc and a metal additive and the tin content plus the zinc content constituting a majority of said corrosion-resistant alloy, said zinc content at least about 10 weight percent of said corrosion-resistant alloy, said tin content at least about 15 weight percent of said corrosion-resistant alloy, and said metal additive selected from the group consisting of a stabilizer agent for inhibiting crystallization of said tin, a coloring agent for reducing the reflectivity of said corrosion-resistant alloy coating, a corrosion-resistant agent for enhancing the corrosion-resistant properties of said corrosion-resistant alloy coating and mixtures thereof.

2. A method as defined in claim 1, wherein said stabilizing agent includes at least an effective amount of metal selected from the group consistent of antimony, bismuth, copper and mixtures thereof.

3. A method as defined in claim 2, wherein said corrosion-resistant agent includes at least an effective amount of metal selected from the group consisting of antimony, bismuth, copper, magnesium, nickel, titanium and mixtures thereof.

4. A method as defined in claim 1, wherein said corrosion-resistant agent includes at least an effective amount of metal selected from the group consisting of antimony, bismuth, copper, magnesium, nickel, titanium and mixtures thereof.

5. A method as defined in claim 1, wherein said corrosion-resistant alloy includes said coloring agent, said coloring agent including at least an effective amount of copper.

6. A method as defined in claim 1, wherein said corrosion-resistant alloy includes said coloring agent, said coloring agent including at least an effective amount of copper.

7. A method as defined in claim 1, wherein said corrosion-resistant alloy includes said coloring agent, said coloring agent including at least an effective amount of copper.

8. A method as defined in claim 1, wherein said corrosion-resistant alloy includes said coloring agent, said coloring agent including at least an effective amount of copper.

9. The method as defined in claim 1, wherein the weight percentage of said tin content plus said zinc content of said corrosion-resistant alloy is at least about 80 weight percent.

10. The method as defined in claim 9, wherein the weight percentage of said tin content plus said zinc content of said corrosion-resistant alloy is at least about 90 weight percent.

11. A method as defined in claim 1, wherein said corrosion-resistant alloy includes up to about two weight percent of a additional additive selected from the group consisting of aluminum, manganese, silicon, cadmium, lead, iron, boron, carbon, chromium, molybdenum, vanadium and mixtures thereof.

12. The method as defined in claim 1, wherein said metallic alloy is a two-phase alloy of tin and zinc comprising:

space="preserve" listing-type="tabular">______________________________________ Tin 15-90% Zinc 10-85% Magnesium 0.0-2% Nickel 0.0-2% Copper 0.0-2% Titanium 0.0-1% Aluminum 0.0-2% Antimony 0.0-2% Bismuth 0.0-1.7% Iron 0.0-1% Lead 0.0-0.5%. ______________________________________

13. A method as defined in claim 1, including the step of controlling the thickness of said corrosion-resistant coating on each side of said metal strip to about 0.0001 to about 0.05 inch as said metal strip exits said molten bath.

14. The method as defined in claim 13, wherein thickness of said coating is about 0.001 to about 0.003 inch.

15. The method as defined in claim 1, wherein said residence time is about 0.08 to about 10 minutes.

16. The method as defined in claim 15, wherein said residence time is less than about one minute.

17. The method as defined in claim 1, including the step of applying an intermediate metal layer to the surface of said metal strip prior to passing said metal strip through said molten bath of said corrosion-resistance alloy.

18. The method as defined in claim 17, wherein said intermediate metal layer is selected from the group consisting of tin, chromium, nickel and copper.

19. The method as defined in claim 1, wherein said metal strip is a metal selected from the group consisting of carbon steel, stainless steel, copper, nickel alloys, tin, titanium and bronze.

20. The method as defined in claim 1, wherein the thickness of said metal strip is about 0.005 to about 0.1 inch.

21. The method as defined in claim 1, including the step of pre-heating said metal strip prior to passing said metal strip through said molten bath.

22. The method as defined in claim 1, including the step of pre-treating said metal strip to substantially remove oxides from the surface of said metal strip prior to passing said metal strip through said molten bath.

23. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin ≧

20% Zinc ≦

80%. ______________________________________

24. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin ≧

25% Zinc ≦

75%. ______________________________________

25. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin ≧

30% Zinc ≦

70%. ______________________________________

26. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin ≧

35% Zinc ≦

65%. ______________________________________

27. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin ≧

40% Zinc ≦

60%. ______________________________________

28. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin ≧

45% Zinc ≦

55%. ______________________________________

29. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin ≧

50% Zinc ≦

50%. ______________________________________

30. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin ≧

55% Zinc ≦

45%. ______________________________________

31. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin ≧

60% Zinc ≦

40%. ______________________________________

32. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin ≧

65% Zinc ≦

35%. ______________________________________

33. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin ≧

70% Zinc ≦

30%. ______________________________________

34. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin ≧

75% Zinc ≦

25%. ______________________________________

35. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin ≧

80% Zinc ≦

20%. ______________________________________

36. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin ≧

85% Zinc ≦

15%. ______________________________________

37. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin 20-90% Zinc 10-80% Aluminum 0.0-0.5% Antimony 0.0-2% Boron 0.0-0.01% Bismuth 0.0-1.5% Cadmium 0.0-0.1% Carbon 0.0-0.5% Chromium 0.0-0.5% Copper 0.0-2% Iron 0.0-1% Lead 0.0-0.5% Magnesium 0.0-0.4% Manganese 0.0-0.1% Molybdenum 0.0-0.1% Nickel 0.0-1% Silicon 0.0-0.5% Titanium 0.0-0.15% Vanadium 0.0-0.1%. ______________________________________

38. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin 20-65% Zinc 35-80% Aluminum 0.0-0.3% Antimony and/or 0.0-1% Bismuth Copper 0.0-1% Iron 0.0-0.6% Lead 0.0-0.5% Magnesium 0.0-0.4% Manganese 0.0-0.1% Nickel 0.0-0.7% Titanium 0.0-0.15% ______________________________________

and said tin content plus said zinc content is at least about 95 weight percent.

39. A method as defined in claim 1, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin 20-50% Zinc 50-80% Aluminum 0.0-0.3% Antimony and/or 0.005-0.5% Bismuth Cadmium 0.0-0.05% Copper 0.0-0.2% Iron 0.0-0.6% Lead 0.0-0.4% Magnesium 0.0-0.1% Manganese 0.0-0.05% Nickel 0.0-0.1% Silicon 0.0-0.1% Titanium 0.0-0.15% ______________________________________

said tin content plus said zinc content at least about 98 weight percent.

40. A method of producing a coated metal strip having corrosion-resistant properties comprising the steps of:

(a) providing a metal strip from a roll of metal strip;

(b) unrolling said metal strip from said roll;

(c) applying an intermediate metal layer to the surface of said metal strip; and

,

(d) coating said metal strip with a corrosion-resistant alloy by passing said strip through a molten bath of said corrosion-resistant alloy such that the residence time of said strip in said molten alloy is sufficient to deposit a layer of said alloy on the surface of said strip, said corrosion-resistant alloy comprising tin, zinc and a metal additive and the tin content plus the zinc content constituting a majority of said corrosion-resistant alloy, said zinc content at least about 10 weight percent of said corrosion-resistant alloy, said tin content at least 15 weight percent of said corrosion-resistant alloy, and said metal additive selected from the group consisting of a stabilizing agent for inhibiting crystallization of said tin, a coloring agent for reducing the reflectivity of said corrosion-resistant alloy, a corrosion-resistant agent for enhancing the corrosion-resistant properties of said corrosion-resistant alloy and mixtures thereof, said stabilizing agent including at least an effective amount of metal selected from the group consistent of antimony, bismuth, copper and mixtures thereof.

41. A method as defined in claim 40, wherein said corrosion-resistant agent includes at least an effective amount of metal selected from the group consisting of antimony, bismuth, copper, magnesium, nickel, titanium and mixtures thereof.

42. A method as defined in claim 41, wherein said coloring agent includes at least an effective amount of copper.

43. A method as defined in claim 40, wherein said coloring agent includes at least an effective amount of copper.

44. The method as defined in claim 40, wherein the weight percentage of said tin content plus the zinc content of said corrosion-resistant alloy is at least about 80 weight percent.

45. The method as defined in claim 41, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin 15-90% Zinc 10-85% Magnesium 0.0-2% Nickel 0.0-2% Copper 0.0-2% Titanium 0.0-1% Aluminum 0.0-2% Antimony 0.0-2% Bismuth 0.0-1.7% Iron 0.0-1% Lead 0.0-0.5%. ______________________________________

46. The method as defined in claim 40, wherein said intermediate metal layer is selected from the group consisting of tin, chromium, nickel and copper.

47. The method as defined in claim 40, wherein said metal strip is a metal selected from the group consisting of carbon steel, stainless steel, copper, nickel alloys, tin, titanium and bronze.

48. A method of producing a coated metal strip with a corrosive-resistant alloy comprising the steps of:

a) selecting a metal strip formed of a given metal and having an exposed surface and a thickness of less than about 0.20 inch;

b) unrolling said metal strip from a coil of said metal strip;

c) hot dip coating said metal strip with a corrosive-resistant coating by continuously passing said metal strip in a longitudinal direction at a speed through a molten bath of said corrosion-resistant alloy, said molten bath having a temperature of at least about 449°

F., said metal strip having a residence time in said molten bath of about 0.08 to about 10 minutes to deposit a substantially uninterrupted layer of said corrosion-resistant alloy, said layer of corrosion-resistant alloy having a substantially uniform thickness of at least about 0.0001 inch on each side of the exposed surface of said metal strip, said passing of said metal strip through said molten bath forming an intermetallic interface comprising an interface alloy constituting a heat created mixture of said given metal and said corrosion-resistant alloy and having a thickness of about 1 to about 10 microns, said corrosion-resistant alloy comprising at least about 15 weight percent tin, at least about 10 weight percent zinc and a metal additive, said tin content plus said zinc content at least about 80 weight percent, said metal additive selected from the group consisting of a stabilizing agent for inhibiting crystallization of said tin, a coloring agent for reducing the reflectivity of said corrosion-resistant alloy coating, a corrosion-resistant agent for enhancing the corrosion-resistant properties of said corrosion-resistant alloy coating and mixtures thereof, said stabilizing agent including at least an effective amount of metal selected from the group consisting of antimony, bismuth, copper and mixtures thereof, said corrosion-resistant agent including at least an effective amount of a metal selected from the group consisting of antimony, bismuth, copper, magnesium, nickel, titanium and mixtures thereof, and said coloring agent including at least an effective amount of copper.

49. The method as defined in claim 48, including the step of pre-treating said exposed surface of said metal strip to substantially remove oxides from said exposed surface.

50. The method as defined in claim 48, wherein said alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin 15-90% Zinc 10-85% Aluminum 0.0-2% Antimony 0.0-2% Bismuth 0.0-1.7% Copper 0.0-2% Lead 0.0-0.5% Iron 0.0-1% Magnesium 0.0-2% Nickel 0.0-2% Titanium 0.0-1%. ______________________________________

51. The method as defined in claim 48, including the step of applying an intermediate metal layer to said exposed surface of said metal strip prior to passing said metal strip through said molten bath.

52. The method as defined in claim 51, wherein said intermediate metal layer is selected from the group consisting of tin, chromium, nickel or copper.

53. A method as defined in claim 48, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin 20-90% Zinc 10-80% Aluminum 0.0-0.5% Antimony 0.0-2% Boron 0.0-0.01% Bismuth 0.0-1.5% Cadmium 0.0-0.1% Carbon 0.0-0.5% Chromium 0.0-0.5% Copper 0.0-2% Iron 0.0-1% Lead 0.0-0.5% Magnesium 0.0-0.4% Manganese 0.0-0.1% Molybdenum 0.0-0.1% Nickel 0.0-1% Silicon 0.0-0.5% Titanium 0.0-0.15% Vanadium 0.0-0.1%. ______________________________________

54. A method as defined in claim 48, wherein said corrosion-resistant alloy comprises:

space="preserve" listing-type="tabular">______________________________________ Tin 20-65% Zinc 35-80% Aluminum 0.0-0.3% Antimony and/or 0.0-1% Bismuth Copper 0.0-1% Iron 0.0-0.6% Lead 0.0-0.5% Magnesium 0.0-0.4% Manganese 0.0-0.1% Nickel 0.0-0.7% Titanium 0.0 0.15% ______________________________________

and said tin content plus said zinc content is at least about 95 weight percent.

55. A method as defined in claim 48, wherein said coating comprises:

space="preserve" listing-type="tabular">______________________________________ Tin 20-50% Zinc 50-80% Aluminum 0.0-0.3% Antimony and/or 0.005-0.5% Bismuth Cadmium 0.0-0.05% Copper 0.0-0.2% Iron 0.0-0.6% Lead 0.0-0.4% Magnesium 0.0-0.1% Manganese 0.0-0.05% Nickel 0.0-0.1% Silicon 0.0-0.1% Titanium 0.0-0.15% ______________________________________

and said tin content plus said zinc content at least about 98 weight percent.

56. The method as defined in claim 48, wherein said corrosion-resistant alloy comprises about 0.005 to about 1.6 weight percent copper.

57. The method as defined in claim 56, wherein said corrosion-resistant alloy comprises about 1.0 to about 1.5 weight percent copper.

58. The method as defined in claim 48, wherein said corrosion-resistant alloy comprises about 0.3 to about 1.0 weight percent nickel.

59. The method as defined in claim 58, wherein said corrosion-resistant alloy comprises about 0.7 weight percent nickel.

60. The method as defined in claim 48, wherein said corrosion-resistant alloy comprises about 0.1 to about 1.0 weight percent magnesium.

61. The method as defined in claim 60, wherein said corrosion-resistant alloy comprises about 0.1 to about 0.4 weight percent magnesium.

62. The method as defined in claim 48, wherein said corrosion-resistant alloy comprises about 0.01 to about 1.0 weight percent titanium.

63. The method as defined in claim 62, wherein said corrosion-resistant alloy comprises about 0.01 to about 0.5 weight percent titanium.

64. The method as defined in claim 63, wherein said corrosion-resistant alloy comprises about 0.01 to about 0.15 weight percent titanium.

65. The method as defined in claim 48, wherein said corrosion-resistant alloy comprises about 0.01 to about 1.0 weight percent aluminum.

66. The method as defined in claim 48, wherein said corrosion-resistant alloy comprises about 0.01 to about 0.5 weight percent aluminum.

68. The method as defined in claim 48, wherein said given metal is a metal selected from the group consisting of carbon steel, stainless steel, copper, nickel alloys, tin, titanium and bronze.

69. The method as defined in claim 68, wherein said given material is stainless steel.

70. The method as defined in claim 68, wherein said given material includes copper.

67. The method as defined in 66, wherein said corrosion-resistant alloy comprises 0.01 to about 0.3 weight percent aluminum.