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US3768149A - Treatment of metal articles - Google Patents

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US3768149A
US3768149A US00302204A US3768149DA US3768149A US 3768149 A US3768149 A US 3768149A US 00302204 A US00302204 A US 00302204A US 3768149D A US3768149D A US 3768149DA US 3768149 A US3768149 A US 3768149A
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Prior art keywords
alloy
burrs
aluminum
refrigerant
plates
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US00302204A
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O Swaney
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Lockheed Martin Tactical Systems Inc
Maxar Space LLC
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Philco Ford Corp
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Assigned to LORAL AEROSPACE CORP. A CORPORATION OF DE reassignment LORAL AEROSPACE CORP. A CORPORATION OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: FORD AEROSPACE CORPORATION, A DE CORPORATION
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
    • B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
    • B23P15/26—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass heat exchangers or the like
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/03—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with plate-like or laminated conduits
    • F28D1/0308—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with plate-like or laminated conduits the conduits being formed by paired plates touching each other
    • F28D1/0325—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with plate-like or laminated conduits the conduits being formed by paired plates touching each other the plates having lateral openings therein for circulation of the heat-exchange medium from one conduit to another
    • F28D1/0333—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with plate-like or laminated conduits the conduits being formed by paired plates touching each other the plates having lateral openings therein for circulation of the heat-exchange medium from one conduit to another the plates having integrated connecting members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F3/00—Plate-like or laminated elements; Assemblies of plate-like or laminated elements
    • F28F3/02—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations
    • F28F3/025—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations the means being corrugated, plate-like elements
    • F28F3/027—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations the means being corrugated, plate-like elements with openings, e.g. louvered corrugated fins; Assemblies of corrugated strips
    • 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
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S72/00—Metal deforming
    • Y10S72/70—Deforming specified alloys or uncommon metal or bimetallic work
    • 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
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/4935—Heat exchanger or boiler making
    • 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
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/4998—Combined manufacture including applying or shaping of fluent material
    • Y10T29/49982—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.]
    • Y10T428/12736—Al-base component
    • Y10T428/12764—Next to Al-base component

Definitions

  • a fin and plate type heat exchanger made by a vacuum brazing process comprises dish-shaped plates positioned in confronting relation to form refrigerant passages therebetween, and in back-to-back relation to form air passages therethrough.
  • Heat exchange fins are disposed in the air passages and extend between the backs of adjacent plates.
  • Spacer fins are disposed in the refrigerant passages between the plates to serve as structural reinforcing members and to afford turbulent flow of the refrigerant to enhance heat exchange.
  • the spacer fins Prior to assembly and brazing, the spacer fins are formed by lancing and convoluting a thin blank, such as aluminum plate, from which burrs must be removed.
  • the blank is coated with a clad, such as an alloy of aluminum, magnesium and silicon, prior to lancing and convoluting, so that, in the brazing operation, the clad alloy forms a low melting temperature eutectic alloy with the material of the burrs effectively dissolving them, and leaving a smooth surface upon solidification.
  • a clad such as an alloy of aluminum, magnesium and silicon
  • This invention relates to the treatment of metals, and especially to a novel method for removing burrs from stamped metal articles. While of broader applicability, the method has particular utility in the fabrication of so-called fin and plate type heat exchangers useful in the field of refrigeration.
  • heat exchangers of this type have been the source of contaminants arising from dislodgement of burrs and the like primarily from the lanced and convoluted internal spacer plate positioned in the refrigerant passages. For rather obvious reasons such plates have become known as turbulator plates.
  • the invention has as a general objective the provision of a novel method for removing burrs from metal articles.
  • the invention contemplates a method for removing burrs and the like from lanced and convoluted sections formed in a blank sheet of metal, comprising the steps of: coating said blank sheet with an alloy of said metal having a melting temperature below the melting temperature of said metal; forming said lanced and convoluted sections; and elevating the temperature of said coated metal sheet to a value sufficient to melt said coating and effectively to dissolvesaid burrs by formation of a eutectic alloy of said metal burrs with said coating. Subsequently, said metal sheet is permitted to cool,
  • Such a process offers numerous advantages over heretofore known deburring operations involving use of abrasives, chemicals, heat, and the like. Such prior art operations tend not to be uniformly effective and require an additional, final cleaning step. In contrast, the process contemplated by my invention achieves consistently uniform results, and is inexpensive since it is carried out concurrently with a final vacuum brazing step in assembling a heat exchanger.
  • FIG. 1 is a perspective showing of elements of a heat exchanger assembled fortreatment in accordance with the method contemplated by my invention
  • FIG. 2 is a fragmentary sectional view taken generally along the line indicated by arrows 2-2 applied to FIG. 1, and illustrating to particular advantage the lanced and convoluted spacer plate from which burrs are to be removed in accordance with principles of my invention;
  • FIG. 3 is a fragmentary sectional view taken generally along the line indicated by arrows 3-3 as applied to FIG. 1, and illustrating further structural features of elements of the assembly on which the method is performed,
  • FIG. 4 is an enlarged showing of a portion of the section illustrated in FIG. 2, and further illustrating the nature and locations of metal burrs to be removed;
  • FIG. 5 is an elevational showing, partly in section, of the heat exchangers positioned within a low pressure vacuum furnace operable to braze the heat exchangers, in achievement of teachings of the invention.
  • a heat exchanger 10 of the fin and plate type includes a plurality of dish-shaped plates 11 positioned in confronting relation to form refrigerant passages therebetween and in back-to-back relation to form air passages therethrough.
  • Plates 11 include oppositely dished, end portions 21 also confronting one another, provided with apertures 22 and cooperably disposed to form refrigerant flow headers for the aforementioned passages.
  • Inlet and outlet ports 23, 24 are provided in bracket means 25 extending over and affixed to the end-most plates 11.
  • Sinuous heat exchange fins 12 are disposed in the air passages and extend between backs of plates 1 l, and between end-most plates 11 and bracket means 25.
  • Spacer fin elements 13 are disposed in the refrigerant-passages between plates 11, both to serve as structural members and to afford turbulent flow of the refrigerant for improved heat exchange.
  • Spacer fin elements 13 are fabricated by forming lanced and convoluted sections in somewhat staggered array, as seen at 14 (FIGS. 2, 3 and 4), in a thin blank such as aluminum plate, to form a plurality of tortuous refrigerant flow paths.
  • convoluted sections 14 enhance turbulent flow of the refrigerant, with consequent improvement in the heat exchange relationship between the refrigerant and plates 11, as air is caused to flow between plates 11, and over fins 12, to give up heat to the refrigerant.
  • burrs 15 In the course of fabrication by lancing and convoluting the blank, numerous burrs 15, such as are shown in FIG. 4, are formed on the cut metal and must be removed, since in the course of operation of a heat exchanger of this type it has been found that burrs 15 become dislodged by the flowing refrigerant and are carried through the refrigerant flow circuit as contaminants. It is the removal of these burrs to which the invention is particularly directed.
  • this potential problem is readily met by coating a suitable blank comprising a flat aluminum sheet having overall dimensions preferably of the order described, with an alloy of aluminum, magnesium, and silicon prior to the lancing and convoluting operation, so that during the brazing operation to be described in connection with FIG. 5, the coating will form a low melting temperature eutectic alloy with the material of the burrs l5, effectively dissolving them and leaving a smooth surface upon solidification.
  • vacuum brazing is performed in a conventional vacuum furnace 16 provided with a heater element 17 connected to a source of energy l8 capable of affording an internal environmental temperature in the order of 1,l F. to 1,200 F., and vacuum pumping system 19 capable of producing a vacuum in the range from about 1 X torr to about 1 X 10' torr.
  • heat exchangers 10 held in sub-assembled form as illustrated in FIG. 1, are placed on suitable supporting means, such as shelf or rack 20, within furnace 16.
  • suitable supporting means such as shelf or rack 20
  • each of the elements of the heat exchanger, including the fin spacer element 13 will have been clad with a fluxless brazing alloy of a preferred composition comprising 7 percent silicon, 2 to 3 percent magnesium, and a balance of aluminum.
  • the brazing alloy has a melting temperature in the range from about l,070 F. to about 1,130 F.
  • the fin spacer blank comprises a sheet of 3003 aluminum, having a melting temperature in the range from about 1,198 to about l,205 F, which, of course, is above the melting temperature of the brazing alloy.
  • the sub-assemblied heat exchangers 10 as described are placed in furnace l6, and the pressure is reduced to a vacuum preferably of about 1 X 10 torr, and the temperature is elevated preferably to about 1,l30 F, to melt the brazing alloy.
  • This pressure and temperature environment is held for about three minutes, and in particular accordance with the invention, the alloy on spacer 10 melts and forms a eutectic solution with the burrs of aluminum, effectively dissolving the burrs and leaving a smooth surface.
  • the vacuum is then removed, the oven heater deenergized, and the heat exchanger sub-assemblies 10 permitted to cool in preparation for such further processing as may be necessary.
  • a method of manufacturing a metal sheet having lanced and convoluted sections, which sheet is free of burrs and the like comprising the steps of: providing a blank sheet coated with an alloy of said metal having a melting temperature below the melting temperature of said metal; forming said lanced and convoluted sections; and heating said coated metal sheet after such forming to a temperature sufficient to melt said coating and to effect formation of a eutectic alloy of said metal burrs with said alloy coating, effectively dissolving said burrs and leaving smooth surfaces on said lanced and convoluted sections.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Pressure Welding/Diffusion-Bonding (AREA)

Abstract

A fin and plate type heat exchanger made by a vacuum brazing process comprises dish-shaped plates positioned in confronting relation to form refrigerant passages therebetween, and in backto-back relation to form air passages therethrough. Heat exchange fins are disposed in the air passages and extend between the backs of adjacent plates. Spacer fins are disposed in the refrigerant passages between the plates to serve as structural reinforcing members and to afford turbulent flow of the refrigerant to enhance heat exchange. Prior to assembly and brazing, the spacer fins are formed by lancing and convoluting a thin blank, such as aluminum plate, from which burrs must be removed. The blank is coated with a clad, such as an alloy of aluminum, magnesium and silicon, prior to lancing and convoluting, so that, in the brazing operation, the clad alloy forms a low melting temperature eutectic alloy with the material of the burrs effectively dissolving them, and leaving a smooth surface upon solidification.

Description

United States Patent [1 1 Swaney, Jr.
[ TREATMENT OF METAL ARTICLES [75] Inventor: Omer'William Swaney,Jr.,
Richmond, Ind.
[73] Assignee: Philco-Ford Corporation,
Philadelphia, Pa.
[22] Filed: Oct. 30, 1972 [21] Appl. No.: 302,204
Related US. Application Data [62] Division of Ser. No. 124,747, March 16, 1971,
v Primary Egaminer-Richard B. Lazarus Attorney-Carl H. Synnestvedt 57 ABSTRACT A fin and plate type heat exchanger made by a vacuum brazing process comprises dish-shaped plates positioned in confronting relation to form refrigerant passages therebetween, and in back-to-back relation to form air passages therethrough. Heat exchange fins are disposed in the air passages and extend between the backs of adjacent plates. Spacer fins are disposed in the refrigerant passages between the plates to serve as structural reinforcing members and to afford turbulent flow of the refrigerant to enhance heat exchange. Prior to assembly and brazing, the spacer fins are formed by lancing and convoluting a thin blank, such as aluminum plate, from which burrs must be removed. The blank is coated with a clad, such as an alloy of aluminum, magnesium and silicon, prior to lancing and convoluting, so that, in the brazing operation, the clad alloy forms a low melting temperature eutectic alloy with the material of the burrs effectively dissolving them, and leaving a smooth surface upon solidification.
m a mii Praise i es.
TREATMENT OF METAL ARTICLES This is a division of application Ser. No. 124,747, filed Mar. 16, 1971 and now abandoned.
BACKGROUND OF THE INVENTION This invention relates to the treatment of metals, and especially to a novel method for removing burrs from stamped metal articles. While of broader applicability, the method has particular utility in the fabrication of so-called fin and plate type heat exchangers useful in the field of refrigeration.
In refrigeration apparatus, such as automobile airconditioners, vacuum brazed fin-and-plate heat exchanger assemblies have exhibited a number of advantages, particularly economy of fabrication and efficiency of operation. However heat exchangers of this type have been the source of contaminants arising from dislodgement of burrs and the like primarily from the lanced and convoluted internal spacer plate positioned in the refrigerant passages. For rather obvious reasons such plates have become known as turbulator plates.
It has been proposed to overcome these difficulties by resort to special deburring operations. However these are inherently costly and time consuming. I have discovered that the need for such special deburring operations can be eliminated by fabricating the turbulator plates from a suitably clad material, for example making them of sheet aluminum coated or clad with an aluminum-magnesium-silicon alloy. This virtually eliminates problems arising from burr-type contaminants, since during the subsequent vacuum brazing operation, when the heat exchangers are assembled, the alloy coating advantageously melts and forms a eutectic alloy with the aluminum burrs, effectively dissolving them and leaving a smooth surface upon solidification of the alloy coating.
It will therefore be appreciated that the invention has as a general objective the provision of a novel method for removing burrs from metal articles.
It is a further, and more specific objective of the invention to provide an improved method for deburring metal articles, which method can be carried to completion utilizing vacuum brazing techniques. Specifically the invention contemplates eliminating burrs formed during the manufacture of evaporator turbulator plates.
SUMMARY OF THE INVENTION In achievement of the foregoing as well as other general objectives and advantages of the invention, the invention contemplates a method for removing burrs and the like from lanced and convoluted sections formed in a blank sheet of metal, comprising the steps of: coating said blank sheet with an alloy of said metal having a melting temperature below the melting temperature of said metal; forming said lanced and convoluted sections; and elevating the temperature of said coated metal sheet to a value sufficient to melt said coating and effectively to dissolvesaid burrs by formation of a eutectic alloy of said metal burrs with said coating. Subsequently, said metal sheet is permitted to cool,
leaving smooth surfaces on said lanced and convoluted sections.
Such a process offers numerous advantages over heretofore known deburring operations involving use of abrasives, chemicals, heat, and the like. Such prior art operations tend not to be uniformly effective and require an additional, final cleaning step. In contrast, the process contemplated by my invention achieves consistently uniform results, and is inexpensive since it is carried out concurrently with a final vacuum brazing step in assembling a heat exchanger.
The manner in which the objectives and advantages of the invention may best be achieved will be more fully understood from a consideration of the following description, taken in light of the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective showing of elements of a heat exchanger assembled fortreatment in accordance with the method contemplated by my invention;
FIG. 2 is a fragmentary sectional view taken generally along the line indicated by arrows 2-2 applied to FIG. 1, and illustrating to particular advantage the lanced and convoluted spacer plate from which burrs are to be removed in accordance with principles of my invention;
FIG. 3 is a fragmentary sectional view taken generally along the line indicated by arrows 3-3 as applied to FIG. 1, and illustrating further structural features of elements of the assembly on which the method is performed,
FIG. 4 is an enlarged showing of a portion of the section illustrated in FIG. 2, and further illustrating the nature and locations of metal burrs to be removed; and
FIG. 5 is an elevational showing, partly in section, of the heat exchangers positioned within a low pressure vacuum furnace operable to braze the heat exchangers, in achievement of teachings of the invention.
DESCRIPTION OF THE PREFERRED PRACTICE OF THE INVENTION With more detailed reference to FIGS. 1, 2, and .3, ,a heat exchanger 10, of the fin and plate type, includes a plurality of dish-shaped plates 11 positioned in confronting relation to form refrigerant passages therebetween and in back-to-back relation to form air passages therethrough. Plates 11 include oppositely dished, end portions 21 also confronting one another, provided with apertures 22 and cooperably disposed to form refrigerant flow headers for the aforementioned passages. Inlet and outlet ports 23, 24 are provided in bracket means 25 extending over and affixed to the end-most plates 11. Sinuous heat exchange fins 12 are disposed in the air passages and extend between backs of plates 1 l, and between end-most plates 11 and bracket means 25. Spacer fin elements 13 are disposed in the refrigerant-passages between plates 11, both to serve as structural members and to afford turbulent flow of the refrigerant for improved heat exchange.
Spacer fin elements 13 are fabricated by forming lanced and convoluted sections in somewhat staggered array, as seen at 14 (FIGS. 2, 3 and 4), in a thin blank such as aluminum plate, to form a plurality of tortuous refrigerant flow paths. In operation, convoluted sections 14 enhance turbulent flow of the refrigerant, with consequent improvement in the heat exchange relationship between the refrigerant and plates 11, as air is caused to flow between plates 11, and over fins 12, to give up heat to the refrigerant.
The assembly dealt with thus far, and in the following paragraphs, is described in terms of its orientation of elements forthe brazing operation, and no clamping or holding means for these elements, such as a strong back," or the like, will be described, since such structures are well known in this art and need not be shown for an understanding of the invention.
In the course of fabrication by lancing and convoluting the blank, numerous burrs 15, such as are shown in FIG. 4, are formed on the cut metal and must be removed, since in the course of operation of a heat exchanger of this type it has been found that burrs 15 become dislodged by the flowing refrigerant and are carried through the refrigerant flow circuit as contaminants. It is the removal of these burrs to which the invention is particularly directed.
The importance of the need for removal of the burrs will be more fully appreciated when it is considered that in a typical blank of aluminum about 9% in. long X 3% in. wide and 0.012 in. thick, there are formed about 64 convoluted rows each having about 23 convolutions. These convolutions 14 cooperate to provide an effective spacer thickness of about 0.080 in., and each convolution acts as a potential source of contaminants by virtue of the nature of its formation by lancing.
As will be more fully explained in what follows, this potential problem is readily met by coating a suitable blank comprising a flat aluminum sheet having overall dimensions preferably of the order described, with an alloy of aluminum, magnesium, and silicon prior to the lancing and convoluting operation, so that during the brazing operation to be described in connection with FIG. 5, the coating will form a low melting temperature eutectic alloy with the material of the burrs l5, effectively dissolving them and leaving a smooth surface upon solidification.
With reference to FIG. 5, vacuum brazing is performed in a conventional vacuum furnace 16 provided with a heater element 17 connected to a source of energy l8 capable of affording an internal environmental temperature in the order of 1,l F. to 1,200 F., and vacuum pumping system 19 capable of producing a vacuum in the range from about 1 X torr to about 1 X 10' torr.
In carrying out the process, heat exchangers 10, held in sub-assembled form as illustrated in FIG. 1, are placed on suitable supporting means, such as shelf or rack 20, within furnace 16. Prior to such sub-assembly, each of the elements of the heat exchanger, including the fin spacer element 13, will have been clad with a fluxless brazing alloy of a preferred composition comprising 7 percent silicon, 2 to 3 percent magnesium, and a balance of aluminum. The brazing alloy has a melting temperature in the range from about l,070 F. to about 1,130 F. The fin spacer blank comprises a sheet of 3003 aluminum, having a melting temperature in the range from about 1,198 to about l,205 F, which, of course, is above the melting temperature of the brazing alloy.
The sub-assemblied heat exchangers 10 as described are placed in furnace l6, and the pressure is reduced to a vacuum preferably of about 1 X 10 torr, and the temperature is elevated preferably to about 1,l30 F, to melt the brazing alloy. This pressure and temperature environment is held for about three minutes, and in particular accordance with the invention, the alloy on spacer 10 melts and forms a eutectic solution with the burrs of aluminum, effectively dissolving the burrs and leaving a smooth surface. The vacuum is then removed, the oven heater deenergized, and the heat exchanger sub-assemblies 10 permitted to cool in preparation for such further processing as may be necessary.
I claim:
1. A method of manufacturing a metal sheet having lanced and convoluted sections, which sheet is free of burrs and the like, comprising the steps of: providing a blank sheet coated with an alloy of said metal having a melting temperature below the melting temperature of said metal; forming said lanced and convoluted sections; and heating said coated metal sheet after such forming to a temperature sufficient to melt said coating and to effect formation of a eutectic alloy of said metal burrs with said alloy coating, effectively dissolving said burrs and leaving smooth surfaces on said lanced and convoluted sections.
2. The method according to claim 1, and characterized in that said metal comprises essentially aluminum, and said alloy comprises essentially aluminum and silicon.
3. The method according to claim 1, and characterized in that said metal comprises an alloy of about 98.8 percent aluminum and 1.2 percent manganese, and said alloy coating comprises about 7 percent silicon, 2 to 3 percent magnesium, and a balance of aluminum.
4. The method according to claim 1, and characterized further by the inclusion of the step of subjecting said coated metal sheet to a vacuum as it is heated.
5. The method according to claim 4, and further characterized in that said vacuum is in the order of from about 1 X 10 torr to 1 X 10 torr.
6. The method according to claim 2, wherein said alloy has a melting temperature in the range from about 1,070 F to about l,l30 F and heating to melt said coating is carried out at a temperature of about 1,1 30 F, said method characterized further in that said metal sheet is heated in the presence of a vacuum.

Claims (5)

  1. 2. The method according to claim 1, and characterized in that said metal comprises essentially aluminum, and said alloy comprises essentially aluminum and silicon.
  2. 3. The method according to claim 1, and characterized in that said metal comprises an alloy of about 98.8 percent aluminum and 1.2 percent manganese, and said alloy coating comprises about 7 percent silicon, 2 to 3 percent magnesium, and a balance of aluminum.
  3. 4. The method according to claim 1, and characterized further by the inclusion of the step of subjecting said coated metal sheet to a vacuum as it is heated.
  4. 5. The method according to claim 4, and further characterized in that said vacuum is in the order of from about 1 X 10 4 torr to 1 X 10 6 torr.
  5. 6. The method according to claim 2, wherein said alloy has a melting temperature in the range from about 1,070* F to about 1, 130* F and heating to melt said coating is carried out at a temperature of about 1,130* F, said method characterized further in that said metal sheet is heated in the presence of a vacuum.
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Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4402362A (en) * 1977-05-19 1983-09-06 Dubrovsky Evgeny V Plate heat exchanger
EP0203458A1 (en) * 1985-05-15 1986-12-03 Showa Aluminum Corporation Heat-exchanger of plate fin type
EP0234942A1 (en) * 1986-02-28 1987-09-02 Showa Aluminum Kabushiki Kaisha Plate type heat exchanger
US5078207A (en) * 1989-08-26 1992-01-07 Nippondenso Co., Ltd. Heat exchanger and fin for the same
WO1992015831A1 (en) * 1991-03-01 1992-09-17 Long Manufacturing Ltd. Optimized offset strip fin for use in compact heat exchangers
US5209289A (en) * 1991-12-02 1993-05-11 Robinson Fin Machines, Inc. Lanced ruffled turbulizer
EP1072783A1 (en) * 1999-07-30 2001-01-31 Denso Corporation Exhaust gas heat exchanger with tilted segment arrangement
US6213158B1 (en) 1999-07-01 2001-04-10 Visteon Global Technologies, Inc. Flat turbulator for a tube and method of making same
US20010011586A1 (en) * 2000-02-09 2001-08-09 Toru Yamaguchi Heat exchangers and fin for heat exchangers and methods for manufacturing the same
US6502447B2 (en) 1999-12-14 2003-01-07 Voss Manufacturing, Inc. Device and method for manufacturing turbulators for use in compact heat exchangers
US6729388B2 (en) * 2000-01-28 2004-05-04 Behr Gmbh & Co. Charge air cooler, especially for motor vehicles
US20040099408A1 (en) * 2002-11-26 2004-05-27 Shabtay Yoram Leon Interconnected microchannel tube
US7276046B1 (en) * 2002-11-18 2007-10-02 Biosynergy, Inc. Liquid conductive cooling/heating device and method of use
US20090095456A1 (en) * 2007-10-04 2009-04-16 Ktm Kuhler Gmbh Plate heat exchanger
US20100230085A1 (en) * 2008-05-23 2010-09-16 Dana Canada Corporation Turbulizers and method for forming same
US20130205776A1 (en) * 2010-08-26 2013-08-15 Modine Manufacturing Company Waste heat recovery system and method of operating the same
US20140311718A1 (en) * 2011-11-28 2014-10-23 Alfa Laval Corporate Ab Block-type plate heat exchanger with anti-fouling properties
US20180259267A1 (en) * 2017-03-10 2018-09-13 Cooler Master Co.,Ltd. Liquid cooling heat exchanger
US10422588B2 (en) 2014-08-21 2019-09-24 Trane International Inc. Heat exchanger coil with offset fins
US20200370834A1 (en) * 2017-11-27 2020-11-26 Dana Canada Corporation Enhanced heat transfer surface
US11193722B2 (en) * 2018-05-01 2021-12-07 Dana Canada Corporation Heat exchanger with multi-zone heat transfer surface

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US2821772A (en) * 1952-03-29 1958-02-04 Sawhill Tubular Products Inc Method of making fluid-tight heat exchange tubes

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* Cited by examiner, † Cited by third party
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US2821772A (en) * 1952-03-29 1958-02-04 Sawhill Tubular Products Inc Method of making fluid-tight heat exchange tubes

Cited By (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4402362A (en) * 1977-05-19 1983-09-06 Dubrovsky Evgeny V Plate heat exchanger
EP0203458A1 (en) * 1985-05-15 1986-12-03 Showa Aluminum Corporation Heat-exchanger of plate fin type
EP0234942A1 (en) * 1986-02-28 1987-09-02 Showa Aluminum Kabushiki Kaisha Plate type heat exchanger
US5078207A (en) * 1989-08-26 1992-01-07 Nippondenso Co., Ltd. Heat exchanger and fin for the same
AU663305B2 (en) * 1991-03-01 1995-10-05 Long Manufacturing Ltd. Optimized offset strip fin for use in compact heat exchangers
USRE35890E (en) * 1991-03-01 1998-09-08 Long Manufacturing Ltd. Optimized offset strip fin for use in compact heat exchangers
WO1992015831A1 (en) * 1991-03-01 1992-09-17 Long Manufacturing Ltd. Optimized offset strip fin for use in compact heat exchangers
US5209289A (en) * 1991-12-02 1993-05-11 Robinson Fin Machines, Inc. Lanced ruffled turbulizer
US6453711B2 (en) 1999-07-01 2002-09-24 Visteon Global Technologies, Inc. Flat turbulator for a tube and method of making same
US6213158B1 (en) 1999-07-01 2001-04-10 Visteon Global Technologies, Inc. Flat turbulator for a tube and method of making same
EP1072783A1 (en) * 1999-07-30 2001-01-31 Denso Corporation Exhaust gas heat exchanger with tilted segment arrangement
US6247523B1 (en) 1999-07-30 2001-06-19 Denso Corporation Exhaust gas heat exchanger
US6502447B2 (en) 1999-12-14 2003-01-07 Voss Manufacturing, Inc. Device and method for manufacturing turbulators for use in compact heat exchangers
US6729388B2 (en) * 2000-01-28 2004-05-04 Behr Gmbh & Co. Charge air cooler, especially for motor vehicles
EP1123763A2 (en) * 2000-02-09 2001-08-16 Sanden Corporation Heat exchangers and fins for heat exchangers and methods for manufacturing the same
US20010011586A1 (en) * 2000-02-09 2001-08-09 Toru Yamaguchi Heat exchangers and fin for heat exchangers and methods for manufacturing the same
US6901995B2 (en) * 2000-02-09 2005-06-07 Sanden Corporation Heat exchangers and fin for heat exchangers and methods for manufacturing the same
EP1123763A3 (en) * 2000-02-09 2002-09-11 Sanden Corporation Heat exchangers and fins for heat exchangers and methods for manufacturing the same
US7276046B1 (en) * 2002-11-18 2007-10-02 Biosynergy, Inc. Liquid conductive cooling/heating device and method of use
US20040099408A1 (en) * 2002-11-26 2004-05-27 Shabtay Yoram Leon Interconnected microchannel tube
US20050241816A1 (en) * 2002-11-26 2005-11-03 Shabtay Yoram L Interconnected microchannel tube
US8418752B2 (en) * 2007-10-04 2013-04-16 Mahle International Gmbh Plate heat exchanger having a turbulence generator
US20090095456A1 (en) * 2007-10-04 2009-04-16 Ktm Kuhler Gmbh Plate heat exchanger
US20100230085A1 (en) * 2008-05-23 2010-09-16 Dana Canada Corporation Turbulizers and method for forming same
US8151617B2 (en) * 2008-05-23 2012-04-10 Dana Canada Corporation Turbulizers and method for forming same
US20130205776A1 (en) * 2010-08-26 2013-08-15 Modine Manufacturing Company Waste heat recovery system and method of operating the same
US9267414B2 (en) * 2010-08-26 2016-02-23 Modine Manufacturing Company Waste heat recovery system and method of operating the same
US20140311718A1 (en) * 2011-11-28 2014-10-23 Alfa Laval Corporate Ab Block-type plate heat exchanger with anti-fouling properties
US10422588B2 (en) 2014-08-21 2019-09-24 Trane International Inc. Heat exchanger coil with offset fins
US20180259267A1 (en) * 2017-03-10 2018-09-13 Cooler Master Co.,Ltd. Liquid cooling heat exchanger
US20200370834A1 (en) * 2017-11-27 2020-11-26 Dana Canada Corporation Enhanced heat transfer surface
US11454448B2 (en) * 2017-11-27 2022-09-27 Dana Canada Corporation Enhanced heat transfer surface
US11193722B2 (en) * 2018-05-01 2021-12-07 Dana Canada Corporation Heat exchanger with multi-zone heat transfer surface

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