US3482951A - Porcelain enameled aluminum articles - Google Patents

Porcelain enameled aluminum articles Download PDF

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Publication number
US3482951A
US3482951A US654537A US3482951DA US3482951A US 3482951 A US3482951 A US 3482951A US 654537 A US654537 A US 654537A US 3482951D A US3482951D A US 3482951DA US 3482951 A US3482951 A US 3482951A
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United States
Prior art keywords
alloy
sheet
clad
porcelain
cladding
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Expired - Lifetime
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US654537A
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English (en)
Inventor
Dean S Hubbell
Ernest E Howlett
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HH Robertson Co
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HH Robertson Co
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23D—ENAMELLING OF, OR APPLYING A VITREOUS LAYER TO, METALS
    • C23D3/00—Chemical treatment of the metal surfaces prior to coating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
    • Y10T428/12597—Noncrystalline silica or noncrystalline plural-oxide component [e.g., glass, etc.]
    • Y10T428/12604—Film [e.g., glaze, etc.]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12736—Al-base component

Definitions

  • Porcelain enameled articles are prepared from a clad aluminum sheet having a core of heat treatable aluminous alloy and having as the cladding material a high siliconcontent aluminous alloy.
  • the porcelain enameled articles can be successfully prepared without requiring the extensive precleaning and chromating which is mandatory for prior art application of porcelain enamel coatings to aluminous sheets. Spall resistance of the porcelain enamel coating is excellent.
  • This invention relates to porcelain enamel coated articles having an aluminous substrate.
  • Porcelain enamel coatings have been applied experimentally to virtually every known aluminum alloy. Successful commercial products have been achieved only with a limited number of aluminum alloys, e.g., in sheet form, Alloys 1100, 3003 and 6061; in extrusions, Alloy 6061; in castings, Alloys 43, 344 and 356. (Recommended Processing Methods for Porcelain Enamel on Aluminum Alloys, Aluminum Division, Porcelain Enamel Institute, Inc., fourth edition, 1960); Alloys 3S, 52S, 51S and 43 (U.S. Patent 2,719,796); aluminum-magnesium-silicon alloys coated with pure aluminum (German Patent 1,096,149).
  • the porcelain enamel industry has for several years used a clad aluminum alloy sheet as a substrate for receiving a porcelain enamel coating for interior and exterior applications.
  • clad sheets include a core of 6061 alloy and a cladding of lxxx alloy.
  • Such clad alloy sheets can be enameled without darkening or discoloring, permitting application of light pastel colors in a single coat.
  • Those clad aluminum alloy sheets, described in U.S. Patent 3,205,051 at times are prone to a defect known as spalling in which the porcelain enamel loses its bond with the substrate when exposed to the atmosphere.
  • U.S. Patent 3,149,001 describes a substrate for porcelain enamel coatings comprising an aluminous alloy having 0.3 to 1.0% magnesium, 1.0 to 2.2% silicon. These alloys are useful in porcelain enameling so long as a proper pretreatment with acid deoxidizer or chromate is applied.
  • the present porcelain enameled articles are prepared by applying a coating of porcelain enamel slip to a clad aluminum sheet having a core of heat treatable aluminum alloys such as 6061 alloy or 7104 alloy and having a clad surface of aluminum-silicon alloy having a silicon-content from about 1.5 to 15%, but preferably from about 3 to 8% silicon.
  • a typical useful cladding alloy is 4043.
  • a preferred clad aluminum sheet includes a cladding of 4043 alloy on a core of 6061 alloy. The total cladding alloy thickness should constitute about 4 to 15% of the total Vsheet thickness.
  • the cladding alloy may contain other alloying metals and impurities such as copper, magnesium, iron, chromium, manganese, and zinc.
  • the maximum content of such other alloying metals and impurities is about 2%,
  • the magnesium content should be less than 0.1%.
  • the copper content should be less than 0.4%. If the impurity content is as high as 2%, iron should be the principal impurity.
  • This clad aluminous sheet has the desirable properties:
  • the cladding for enameling purposes may be applied on one side only. Preferably the cladding is applied on both sides of the core alloy.
  • the cladding should constitute between 4 and 15% of the sheet thickness on each side preferably about 6-8% of the total thickness.
  • the cladding should have a minimum thickness of 0.002 inch each.
  • FIGURES 1 through 6 inclusive are cross-sectional representations of clad-aluminum sheets and coated cladaluminum sheets according to the present invention.
  • the clad aluminum sheet 10 includes a core 11 of heat treatable aluminous alloy and a cladding 12 of a high-silicon alloy which constitutes 4 to 15 of the total sheet thickness.
  • a porcelain enamel coating 13 is applied to the cladding 12 by familiar heating processes.
  • the opposed surface as seen in FIGURE 3, may be coated with a protective coating 14 such as paint, organic enamel, or even porcelain enamel.
  • the alu-minous sheet 10' is clad on both sides, as seen in FIGURE 4.
  • the core 11' of heat treatable alloy is clad with the high-silicon alloy 12 and with a further alloy 15 Iwhich is preferably the same as the highsilicon alloy 12.
  • a further alloy 15 I which is preferably the same as the highsilicon alloy 12.
  • the second cladding surface 15 may itself be covered with a protective coating 16 of paint, organic enamel, or even porcelain enamel.
  • the present clad sheeting can be successfully coated with porcelain enamel Without requiring the extensive pretreatment.
  • the vitreous enamels which can be used are the relatively low melting point frit compositions which are readily available and which can be used at relatively low temperatures of aluminum porcelainizing-e.g. 850 to 1050 F. These enamels are normally prepared by the enameler from dry vitreous frits which are milled with water and other additives such as opacifiers, stabilizers and the like to form an aqueous slurry, called a porcelain enamel slip.
  • the aqueous slurry is applied to the sheet by spraying in most commercial applications. Occasionally a single coat of porcelain enamel is applied to the metal sheet. In other instances, second coat of porcelain enamel is required in order to achieve satisfactory color uniformity, especially when a light-colored porcelain enamel is desired.
  • U.S. Patent 3,205,051 describes a clad 4aluminum sheet which permits application of light-colored porcelain enamel coatings in a single pass through a porcelain enameling oven.
  • extensive precleaning and chromating must be carried out with the lxxx-clad aluminum sheets.
  • the present invention can achieve single-pass porcelain enameling with medium and dark colors.
  • two coats may be necessary for color uniformity.
  • Sheet A Clad sheets identified as sheet A were Iprepared by applying a 5 percent clad coating of 4043 alloy to one side of a core of 6061 alloy .by hot rolling the two alloys to a final sheet thickness of 0.080 inch.
  • Sheet B Clad sheets identified as sheet B were prepared by applying a 5 percent clad coating of 4043 alloy to one side of a core of 6061 alloy by hot rolling to a thickness of 0.125 inch. Thereafter the sheets were further cold rolled to a final thickness of 0.050 inch.
  • Sheet C A special cladding alloy I was prepared containing 5.02 percent silicon, 0.11 percent copper, 0.34 percent iron and impurities less than 0.01 percent. The alloy I was clad to one side only of a core of 6061 alloy. The cladding was 4 percent of the final sheet thickness, 0.050
  • Sheet D Two porcelain enamel slip formulations S-1 and S-2 were prepared as set forth in Table I.
  • the slip S-2 was milled to a neness of 0.2 percent retained on 325 mesh.
  • the slip was sprayed at specilic gravity 2.04.
  • the coated specimens were fired for l0 to 15 minutes at 545 to 550 C. (l010 to 1020" E).
  • the porcelain enameled aluminum samples were exposed in 5 percent ammonium chloride for 96 hours at 20 C. No. spalling was observed on any of the samples of sheets C or D including those which had been heat-treated and those which had not been heat-treated.
  • a clad aluminum sheet identified herein as sheet E was prepared using a 6061 alloy core and 1100 alloy cladding on one side only.
  • the 1100 alloy had the following analysis:
  • Copper 0.01 percent; iron 0.29 percent; silicon 0.10 percent; balance aluminum.
  • a clad aluminum sheet identied herein as sheet F was prepared by applying to one side only of 6061 alloy core a clad containing 5 percent silicon, 0.10 percent copper, 0.32 percent iron, balance aluminum. This cladding alloy is identified herein as alloy II. The cladding thickness for sheets E and F was 0.0024 inch average.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Cookers (AREA)
  • Coating With Molten Metal (AREA)
  • Insulated Metal Substrates For Printed Circuits (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)
  • Glass Compositions (AREA)
US654537A 1967-07-19 1967-07-19 Porcelain enameled aluminum articles Expired - Lifetime US3482951A (en)

Applications Claiming Priority (1)

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US65453767A 1967-07-19 1967-07-19

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US3482951A true US3482951A (en) 1969-12-09

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US (1) US3482951A (forum.php)
BE (1) BE718308A (forum.php)
DE (1) DE1758620A1 (forum.php)
FR (1) FR1603349A (forum.php)
GB (1) GB1169157A (forum.php)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3690062A (en) * 1970-01-30 1972-09-12 Suwa Seikosha Kk Hard watch case
US3726082A (en) * 1970-01-13 1973-04-10 Citizen Watch Co Ltd Watch case
US3773477A (en) * 1968-12-27 1973-11-20 Aluminum Co Of America Clad aluminum base alloy
US3825993A (en) * 1971-05-27 1974-07-30 Aluminum Co Of America Method of providing article from clad aluminum base alloy
US3850585A (en) * 1970-10-05 1974-11-26 Reynolds Metals Co Composite article
US3893823A (en) * 1972-12-18 1975-07-08 Reynolds Metals Co Cladding system
USRE28527E (en) * 1970-01-13 1975-08-26 Watch case
US5306526A (en) * 1992-04-02 1994-04-26 Ppg Industries, Inc. Method of treating nonferrous metal surfaces by means of an acid activating agent and an organophosphate or organophosphonate and substrates treated by such method
US5516586A (en) * 1991-06-11 1996-05-14 Sprayforming Developments Method for protecting a metal surface
US6258418B1 (en) 1998-06-24 2001-07-10 Ronald A. Rudder Method for producing diamond-tiled cooking utensils and other workpieces for durable stick-resistant surfaces
US10926319B2 (en) 2014-12-22 2021-02-23 Novelis Inc. Clad sheets for heat exchangers

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005010568A1 (de) 2005-03-04 2006-09-07 Braun Gmbh Haarformgerät

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2932584A (en) * 1958-02-28 1960-04-12 Robertson Co H H Enameling of aluminum alloys
US3149001A (en) * 1962-04-05 1964-09-15 Aluminum Co Of America Enameled aluminous metal product
US3205051A (en) * 1962-05-25 1965-09-07 Robertson Co H H Light-colored porcelain-enameled aluminum articles and clad-aluminum sheets therefor
US3377145A (en) * 1964-11-09 1968-04-09 Aluminum Co Of America Enamelled aluminum composite base

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2932584A (en) * 1958-02-28 1960-04-12 Robertson Co H H Enameling of aluminum alloys
US3149001A (en) * 1962-04-05 1964-09-15 Aluminum Co Of America Enameled aluminous metal product
US3205051A (en) * 1962-05-25 1965-09-07 Robertson Co H H Light-colored porcelain-enameled aluminum articles and clad-aluminum sheets therefor
US3377145A (en) * 1964-11-09 1968-04-09 Aluminum Co Of America Enamelled aluminum composite base

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3773477A (en) * 1968-12-27 1973-11-20 Aluminum Co Of America Clad aluminum base alloy
US3726082A (en) * 1970-01-13 1973-04-10 Citizen Watch Co Ltd Watch case
USRE28527E (en) * 1970-01-13 1975-08-26 Watch case
US3690062A (en) * 1970-01-30 1972-09-12 Suwa Seikosha Kk Hard watch case
US3850585A (en) * 1970-10-05 1974-11-26 Reynolds Metals Co Composite article
US3825993A (en) * 1971-05-27 1974-07-30 Aluminum Co Of America Method of providing article from clad aluminum base alloy
US3893823A (en) * 1972-12-18 1975-07-08 Reynolds Metals Co Cladding system
US5516586A (en) * 1991-06-11 1996-05-14 Sprayforming Developments Method for protecting a metal surface
US5306526A (en) * 1992-04-02 1994-04-26 Ppg Industries, Inc. Method of treating nonferrous metal surfaces by means of an acid activating agent and an organophosphate or organophosphonate and substrates treated by such method
US6258418B1 (en) 1998-06-24 2001-07-10 Ronald A. Rudder Method for producing diamond-tiled cooking utensils and other workpieces for durable stick-resistant surfaces
US10926319B2 (en) 2014-12-22 2021-02-23 Novelis Inc. Clad sheets for heat exchangers

Also Published As

Publication number Publication date
DE1758620A1 (de) 1971-03-18
GB1169157A (en) 1969-10-29
BE718308A (forum.php) 1968-12-31
FR1603349A (en) 1971-04-05

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