US20190162492A1 - Aluminum alloy fin material, aluminum alloy brazing sheet, and heat exchanger - Google Patents

Aluminum alloy fin material, aluminum alloy brazing sheet, and heat exchanger Download PDF

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Publication number
US20190162492A1
US20190162492A1 US16/091,776 US201716091776A US2019162492A1 US 20190162492 A1 US20190162492 A1 US 20190162492A1 US 201716091776 A US201716091776 A US 201716091776A US 2019162492 A1 US2019162492 A1 US 2019162492A1
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Prior art keywords
aluminum alloy
fin material
fin
heating
thickness
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US16/091,776
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English (en)
Inventor
Tomohito Kurosaki
Junji Ninomiya
Yoshihiko Mizuta
Ryoko FUJIMURA
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UACJ Corp
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UACJ Corp
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Priority claimed from PCT/JP2017/015001 external-priority patent/WO2017179625A1/ja
Assigned to UACJ CORPORATION reassignment UACJ CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: FUJIMURA, RYOKO, KUROSAKI, Tomohito, NINOMIYA, JUNJI, MIZUTA, YOSHIHIKO
Publication of US20190162492A1 publication Critical patent/US20190162492A1/en
Abandoned legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
    • F28F21/08—Constructions of heat-exchange apparatus characterised by the selection of particular materials of metal
    • F28F21/081—Heat exchange elements made from metals or metal alloys
    • F28F21/084—Heat exchange elements made from metals or metal alloys from aluminium or aluminium alloys
    • 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
    • C22C21/02—Alloys based on aluminium with silicon as the next major constituent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
    • B22D11/003—Aluminium alloys
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
    • B22D11/049—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds for direct chill casting, e.g. electromagnetic casting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16—Controlling or regulating processes or operations
    • B22D11/22—Controlling or regulating processes or operations for cooling cast stock or mould
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D21/00—Casting non-ferrous metals or metallic compounds so far as their metallurgical properties are of importance for the casting procedure; Selection of compositions therefor
    • B22D21/002—Castings of light metals
    • B22D21/007—Castings of light metals with low melting point, e.g. Al 659 degrees C, Mg 650 degrees C
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K1/00—Soldering, e.g. brazing, or unsoldering
    • B23K1/0008—Soldering, e.g. brazing, or unsoldering specially adapted for particular articles or work
    • B23K1/0012—Brazing heat exchangers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
    • B23K35/0222—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape for use in soldering, brazing
    • B23K35/0233—Sheets, foils
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
    • B23K35/24—Selection of soldering or welding materials proper
    • B23K35/28—Selection of soldering or welding materials proper with the principal constituent melting at less than 950 degrees C
    • B23K35/286—Al as the principal constituent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
    • B23K35/24—Selection of soldering or welding materials proper
    • B23K35/28—Selection of soldering or welding materials proper with the principal constituent melting at less than 950 degrees C
    • B23K35/286—Al as the principal constituent
    • B23K35/288—Al as the principal constituent with Sn or Zn
    • 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
    • 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
    • C22C21/10—Alloys based on aluminium with zinc as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
    • C22F1/043—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys with silicon as the next major constituent
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/02—Tubular elements of cross-section which is non-circular
    • F28F1/022—Tubular elements of cross-section which is non-circular with multiple channels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
    • F28F1/24—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely
    • F28F1/32—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely the means having portions engaging further tubular elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
    • F28F21/08—Constructions of heat-exchange apparatus characterised by the selection of particular materials of metal
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
    • F28F1/24—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely
    • F28F1/32—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely the means having portions engaging further tubular elements
    • F28F1/325—Fins with openings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F2215/00—Fins
    • F28F2215/12—Fins with U-shaped slots for laterally inserting conduits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F2275/00—Fastening; Joining
    • F28F2275/04—Fastening; Joining by brazing

Definitions

  • the present disclosure relates to an aluminum alloy fin material, an aluminum alloy brazing sheet, and a heat exchanger.
  • brazing fins of which the skin materials are clad with Al—Si-based alloys have been commonly used as aluminum alloy fin materials having the function of being bonded to tubes by heating.
  • a skin material is melted and flows in the case of heating and bonding, and therefore, a sheet thickness is decreased according to the melting.
  • Patent Literature 1 discloses a fin materials having the function of being bonded by heating with a single-layer material but does not disclose suppression of a decrease in sheet thickness.
  • plural notch grooves opened to penetrate the same positions of the sheet-shaped fins are disposed along each of the end edges.
  • a structure is made in which collars are formed on the notch grooves so as to come in contact with a surface of a flat tube through which a heat-transfer fluid flows, and in which the flat tube is fit in the notch grooves. The tube is assembled, heated, and bonded in the state of extending in the direction of overlapping such sheet-shaped fins, whereby the heat exchanger is produced.
  • a decrease in sheet thickness due to the heating for bonding results in the deterioration of rigidity due to a decrease in the cross-sectional area of the fin.
  • a brazing fin having a decreased cladding ratio.
  • a decrease in cladding ratio in the fin material having a small sheet thickness precludes production of the fin material.
  • Patent Literature 1 Japanese Patent No. 5021097
  • An objective of the present disclosure is to provide an aluminum alloy fin material, an aluminum alloy brazing sheet, and a heat exchanger, which have a small decrease in the sheet thickness of the fin material, the low deterioration of bondability, and the low deterioration of rigidity in bonding and heating.
  • an aluminum alloy fin material according to a first aspect of the present disclosure is:
  • an aluminum alloy fin material including:
  • the aluminum alloy may further contain one or more selected from 0.01 to 2.00 mass % Fe, 0.05 to 2.00 mass % Mn, 0.05 to 6.00 mass % Zn, and 0.05 to 1.50 mass % Cu.
  • An aluminum alloy brazing sheet according to a second aspect of the present disclosure is:
  • an aluminum alloy brazing sheet including, as a skin material, the aluminum alloy fin material, the aluminum alloy fin material being clad on a core material including an aluminum alloy.
  • a heat exchanger according to a third aspect of the present disclosure is:
  • a heat exchanger including the aluminum alloy fin material, the aluminum alloy fin material being used in a fin.
  • a heat exchanger according to a fourth aspect of the present disclosure is:
  • a heat exchanger including the aluminum alloy brazing sheet, the aluminum alloy brazing sheet being used in a fin.
  • the aluminum alloy fin material, aluminum alloy brazing sheet, and heat exchanger according to the present disclosure have a small decrease in the sheet thickness of the fin material, the low deterioration of bondability, and the low deterioration of rigidity in bonding and heating. Specifically, since the rate of decrease in sheet thickness after the heating is less than that before the heating for bonding in the fin material, a clearance generated between the fin material and another member at the time of the heating for bonding can be suppressed. As a result, the fin material having high bondability and the brazing sheet using the fin material can be obtained. Since the less decrease in sheet thickness can result in the less deterioration of rigidity after the bonding, the thicknesses of the fin material and the brazing sheet can be reduced, and the weight of the heat exchanger using the fin material and the brazing sheet can be reduced.
  • FIG. 1 is a perspective view of a heat exchanger according to the present embodiment, which is used for evaluating bondability, and in which plate-shaped fin materials and flat tubes are combined;
  • FIG. 2 is a front view of the sheet-shaped fin in FIG. 1 .
  • the present inventors found that the deterioration of the bondability and rigidity of a fin material can be suppressed by controlling the rate of decrease in sheet thickness after bonding the fin material to a tube with respect to a sheet thickness before the bonding in order to solve the problems.
  • it was found that such suppression of the rate of decrease in sheet thickness is achieved by appropriately controlling particles included in a metal structure in the vicinity of a surface layer.
  • the aluminum alloy fin material according to the present embodiment includes an aluminum alloy containing 1.50 to 5.00 mass % Si with the balance of Al and inevitable impurities, and has the function of being bonded by heating with a single layer. Assuming that the thickness of the fin materials is represented by t, a cross section along a thickness direction is considered, which is divided into a cross section portion closer to one surface, from one surface to the half of the thickness t, and a cross section portion closer to the other surface, from the other surface to the half of the thickness t.
  • ⁇ D 2 is defined as the sum of cross-sectional areas ⁇ D 2 in the case of melting all the Si particles that are present in the range of the length W (the area of t ⁇ W) and satisfy D ⁇ L and L+D>0.04 t in the whole of both the one and other cross section portions (hereinafter referred to as “the whole cross section”).
  • This mathematical expression indicates a condition for allowing a melted Si particle to flow onto a surface when the Si particle is melted.
  • the Si particle When being melted, the Si particle reacts with a surrounding matrix and becomes a liquid phase having a spherical shape of which the diameter is about 2 times the diameter of the Si particle.
  • the flow of the liquid phase onto the surface requires that the radius of the liquid phase after the melting, that is, D, which is 1 ⁇ 2 of the diameter 2D of the liquid phase, is not less than the distance L from the surface to the center of the Si particle.
  • D the radius of the liquid phase after the melting
  • This mathematical expression indicates a condition for contributing to a decrease in sheet thickness by 8% or more when a Si particle is melted and flows onto a surface.
  • a Si particle having an equivalent circle diameter D at a distance L from a surface is melted, a distance from the surface to the deepest portion of a liquid phase is L+D.
  • L+D a distance from the surface to the deepest portion of a liquid phase
  • a sheet thickness of L+D is decreased in a site in which the liquid phase has been present.
  • a case in which a decrease L+D in sheet thickness allowed to locally occur due to such one Si particle is more than 4% of the thickness t of the whole cross section in one or the other surface side causes a total decrease in sheet thickness in both of the sides to be more than 8%.
  • a case in which a decrease L+D in sheet thickness allowed to locally occur due to one Si particle is 4% or less of the thickness t of the whole cross section makes a limited contribution to a decrease in sheet thickness. Accordingly, it is necessary to control Si particles in which L+D is more than 4% of the thickness t of the whole cross section in the one or other surface sides. In other words, only the Si particles satisfying L+D>0.04 t are regulated.
  • a decrease in sheet thickness in the one or other surface side is preferably 3% or less, and is more preferably controlled to 2% or less, with respect to the thickness t of the whole cross section, for effectively preventing the deterioration of bondability and rigidity.
  • ⁇ D 2 is low, a site in which a decrease in sheet thickness occurs in the whole cross section is limited.
  • ⁇ D 2 a site in which a decrease in sheet thickness occurs in the whole cross section is increased to decrease the sheet thickness in the whole fin.
  • the rate of ⁇ D 2 to the area (t ⁇ W) of the whole cross section described above is regulated to less than 8%, that is, the area of ⁇ D 2 is regulated to less than 0.08 tW.
  • the preferred range of ⁇ D 2 is 0 ⁇ D 2 ⁇ 0.06 tW.
  • the rate (%) of decrease in sheet thickness in the present embodiment is defined as a value obtained by discarding digits to the right of the decimal point of an actually determined numerical value.
  • Bondability is secured due to the presence of solid solution Si or Si particles satisfying L+D ⁇ 0.04 t even when ⁇ D 2 is almost zero, and the amount of liquid phase supplied from Si particles contributing to a decrease in sheet thickness is small.
  • the equivalent circle diameter D of a Si particle is typically about 0 to 10 ⁇ M, and is up to about 30 ⁇ m in a case in which a coarse crystallized product is present.
  • the case of 0 ⁇ m means that Si is completely solid-dissolved and is not present as Si particles.
  • the Si particle refers to: (1) pure Si; and (2) a Si particle containing a slight amount of an element such as Ca or P in part of pure Si.
  • the equivalent circle diameter D of the Si particle can be determined by observing a reflection electron image of a cross section with a scanning electron microscope (SEM). It is preferable to determine the equivalent circle diameter of the Si particle by image analysis of an SEM photograph.
  • the Si particle and other particles are distinguished from each other on the basis of the concentration difference of contrast by SEM-reflection electron image observation.
  • the element such as Ca or P contained in the Si particle can be more precisely specified by an electron probe micro analyzer (EPMA) or the like.
  • the cross section refers to a cross section along the thickness direction of an aluminum alloy material, and may be a cross section along an optional direction such as a cross section along a rolling direction or a cross section along a direction orthogonal to a rolling direction as long as being along the thickness direction.
  • the distance L from the surface layer of the fin material to the center of the Si particle is not more than the sheet thickness and is therefore less than the sheet thickness t.
  • L is determined by measuring a distance from the center of the Si particle to the surface layer of the fin material when the above-described equivalent circle diameter of the Si particle is determined. In such a case, the measurement can be performed by, for example, taking a photograph of an SEM image of a visual field from the surface layer of the fin material to the target Si particle and performing the analysis of the image.
  • the Si particle is not a uniaxial crystal, the intermediate position between the point closest to the surface layer of the fin material and the point farthest from the surface layer of the fin material in the Si particle is regarded as the center of the Si particle.
  • a fin material having a sheet thickness t of about 0.01 to 0.2 mm is preferred from the viewpoint of weight reduction and workability although t is not particularly limited.
  • a thin fin material of about 0.01 to 0.1 mm or a thick fin material of more than 0.1 mm and about 0.2 mm is used.
  • the sheet thickness t of the fin material is preferably measured with a micrometer. In such a case, in order to determine a difference before and after bonding and heating, the difference is evaluated with the arithmetic mean value of measurements of three or more sheet thicknesses at the same position before and after the heating for bonding for each sample.
  • the fin material of the present embodiment exhibits a bonding function with a single layer by melting a part of the material to generate a liquid phase at the time of bonding and heating.
  • Si particles in the material react with a surrounding matrix at the time of the bonding and heating, whereby a part of the liquid phase is generated.
  • melting of the Si particles results in a greater decrease in sheet thickness.
  • the present inventors found that a decrease in sheet thickness is suppressed by controlling the sizes of Si particles in a surface layer.
  • the fin material according to the present embodiment is basically used as a fin material having the function of being bonded by heating with a single layer. However, since the effect of suppressing a decrease in the sheet thickness of a surface layer can be similarly obtained even when a brazing fin is made by cladding the fin material according to the present embodiment on another material (core material), the fin material has an advantage that it is not necessary to decrease a cladding ratio. As described above, the fin material according to the present embodiment can also be used in the form of a clad material (brazing fin).
  • the fin material according to the present embodiment is used as a single-layered material.
  • the effect of suppressing a decrease in sheet thickness in the portion of the fin material according to the present embodiment can also be obtained according to the following description.
  • the aluminum alloy included in the fin material according to the present embodiment contains 1.50 to 5.00 mass % (hereinafter simply referred to as “%”) Si as an essential element with the balance of Al and inevitable impurities.
  • the aluminum alloy may further contain, as first selective additional elements, one or more selected from 0.01 to 2.00% Fe, 0.05 to 2.00% Mn, 0.05 to 6.00% Zn, and 0.05 to 1.50% Cu.
  • Si is an element that generates an Al—Si-based liquid phase and contributes to bonding.
  • the content of Si is less than 1.50%, it is impossible to generate a sufficient amount of liquid phase, the less bleeding of the liquid phase occurs, and the bonding becomes incomplete.
  • the content is more than 5.00%, the amount of generated liquid phase portion in the aluminum alloy material is increased, and therefore, the strength of the aluminum alloy material which is being heated is decreased, thereby precluding maintaining of the shape of a structure.
  • the number of Si particles present in the vicinity of the surface layer is also increased, and therefore, the sheet thickness is also significantly decreased. Accordingly, the content of Si is regulated to 1.50 to 5.00%.
  • the content of Si is preferably 1.50 to 3.50%, and more preferably 2.00 to 3.00%. Since the amount of bleeding liquid phase portion is increased with increasing the volume of the fin material and with increasing a heating temperature, the amount of liquid phase portion required at the time of the heating is adjusted according to the amount Si required depending on the structure of the produced structure and according to a heating temperature at the time of the bonding.
  • Fe has the effect of being slightly solid-dissolved in a matrix to improve strength and having the effect of being dispersed as a crystallized product or precipitate to prevent strength from decreasing particularly at high temperature.
  • a case in which the content of Fe is less than 0.01% not only prevents the above-described effects from being sufficiently obtained but also requires use of a high-purity base metal, thereby resulting in an increase in material cost.
  • a case in which the content of Fe is more than 2.00% results in, during casting, generation of a coarse intermetallic compound, which therefore causes cracking during working, thereby precluding the production of the fin material.
  • the content of Fe is set to 0.01 to 2.00%.
  • the content of Fe is preferably 0.20 to 1.00%.
  • Mn is an additional element that acts as an element which forms, together with Si and Fe, an Al—Mn—Si-based, Al—Mn—Fe—Si-based, or Al—Mn—Fe-based intermetallic compound, and is dispersed in an aluminum matrix to strengthen the fin material, or that acts as an element which is solid-dissolved in an aluminum matrix to strengthen the fin material, thereby improving strength.
  • the content of Mn is more than 2.00%, a coarse intermetallic compound is prone to be formed, and corrosion resistance is deteriorated.
  • the content of Mn is less than 0.05%, the above-described effects become insufficient. Accordingly, the content of Mn is set to 0.05 to 2.00%.
  • the content of Mn is preferably 0.10 to 1.50%.
  • Zn is an element that is effective in the improvement of corrosion resistance due to sacrificial protection action.
  • Zn has the action of being roughly uniformly solid-dissolved in a matrix and allowing natural-potential to be lower.
  • the sacrificial protection action of relatively suppressing the corrosion of a bonded tube can be exhibited by allowing the fin material according to the present embodiment to be baser.
  • the content of Zn is less than 0.05%, the effect of lower potential becomes insufficient.
  • the content of Zn is more than 6.00%, a corrosion rate is increased, self-corrosion resistance is deteriorated, and sacrificial protection action is also deteriorated.
  • the content of Zn is set to 0.05 to 6.00%.
  • the content of Zn is preferably 0.10 to 5.00%.
  • Cu is an element that has the effect of being solid-dissolved in a matrix and improving strength.
  • the content of Cu is more than 1.50%, corrosion resistance is deteriorated.
  • the content of Cu is less than 0.05%, the above-described effects become insufficient. Accordingly, the content of Cu is set to 0.05 to 1.50%.
  • the content of Cu is preferably 0.10 to 1.00%.
  • selective additional elements one or more selected from 0.05 to 2.00% of Mg, 0.05 to 0.30% of In, 0.05 to 0.30% of Sn, 0.05 to 0.30% of Ti, 0.05 to 0.30% of V, 0.05 to 0.30% of Cr, 2.00% or less of Ni, and 0.30% or less of Zr may be further contained as second selective additional elements, instead of or in addition to the first selective additional element described above.
  • Mg exhibits the action of age hardening due to Mg 2 Si after bonding and heating, and strength is improved by the age hardening.
  • Mg is an additional element that exhibits the effect of improvement in strength.
  • the content of Mg is more than 2.00%, Mg reacts with a flux, whereby a compound having a high melting point is formed, and therefore, bondability is significantly deteriorated.
  • the content of Mg is set to 0.05 to 2.00%.
  • the content of Mg is preferably 0.10 to 1.50%.
  • Sn and In show the effect of exhibiting sacrificial protection action.
  • the content of each of Sn and In is more than 0.30%, a corrosion rate is increased, and self-corrosion resistance is deteriorated.
  • the content of each of Sn and In is less than 0.05%, the above-described effects are small. Accordingly, the content of each of Sn and In is set to 0.05 to 0.30%, and is preferably 0.10 to 0.25%.
  • Ti and V exhibit the effects of not only being solid-dissolved in a matrix to improve strength but also being distributed in a layer form to prevent corrosion from proceeding in a sheet thickness direction.
  • the content of each of Ti and V is more than 0.30%, a coarse crystallized product is generated, thereby inhibiting moldability and corrosion resistance.
  • the content of each of Ti and V is less than 0.05%, the effects are small. Accordingly, the content of each of Ti and V is set to 0.05 to 0.30%, and is preferably 0.10 to 0.25%.
  • the content of Cr improves strength by solid solution strengthening and allows crystal grains after heating to be coarsened by the precipitation of an Al—Cr-based intermetallic compound.
  • the content of Cr is set to 0.05 to 0.30% or less, and is preferably 0.10 to 0.25%.
  • Ni is crystallized or precipitated as an intermetallic compound and exhibits the effect of improving strength after bonding by dispersion strengthening.
  • the content of Ni is set to 2.00% or less, and preferably 0.05 to 2.00%. When the content of Ni is more than 2.00%, a coarse intermetallic compound is prone to be formed, workability is deteriorated, and self-corrosion resistance is deteriorated.
  • Zr is precipitated as an Al—Zr-based intermetallic compound and exhibits the effect of improving strength after bonding by dispersion strengthening.
  • the Al—Zr-based intermetallic compound coarsens crystal grains during heating.
  • the content of Zr is set to 0.30% or less.
  • the content of Zr is preferably 0.05 to 0.30%.
  • a selective additional element one or more selected from 0.1000% or less of Be, 0.1000% or less of Sr, 0.1000% or less of Bi, 0.1000% or less of Na, and 0.0500% or less of Ca may be further contained as a third selective additional element, instead of the first selective additional element and second selective additional element described above or in addition to either or both thereof.
  • These elements exhibit the action of allowing bondability to be further favorable by improving the characteristics of a liquid phase by setting the elements in the ranges described above.
  • these trace elements can contribute to suppression of a decrease in sheet thickness by fine dispersion of Si particles. Bondability can be improved by improvement in the flowability of a liquid phase, and/or the like.
  • the preferred ranges of these elements, Be, Sr, Bi, Na, and Ca are 0.0001 to 0.1000%, 0.0001 to 0.1000%, 0.0001 to 0.1000%, 0.0001 to 0.1000%, and 0.0001 to 0.0500%, respectively.
  • Temper may be performed on an O material or may be performed on an H1n material or an H2n material.
  • the sizes of Si particles present in the vicinity of the surface layer are limited.
  • Coarse dispersed particles in a material are known to be greatly influenced by a cooling rate in casting. It is particularly known that since the rate of diffusion of dispersed particles containing Fe or Mn is low, a cooling rate in casting greatly influences the sizes of the dispersed particles, and the higher the cooling rate in the casting is, the finer the particles are.
  • Si particles are known to be finely generated during casting by a slight amount of an additional element such as Sr or Na.
  • the distribution of Si particles in the vicinity of the surface layer is important, and the distribution of the Si particles is relatively greatly affected by retention time at high temperature in a production step after casting because the rate of the diffusion of Si in Al is relatively high. Therefore, in any case of a DC casting method and a continuous casting method, when retention is performed at a temperature of 530° C. or more in a production step after casting, the time of the retention is set to 10 hours or less. In a still more preferred heating condition, a retention time in the case of performing retention at a temperature of 520° C. or more is set to 0 to 10 hours.
  • a retention time of 0 hour means that retention is stopped immediately after a predetermined retention temperature has been reached.
  • the restrictions of such heating conditions enable all Si particles that are present in the range of the length W in the whole cross section of the fin material and satisfy D ⁇ L and L+D>0.04 t to satisfy 0 ⁇ D 2 ⁇ 0.08 tW.
  • coarsening due to Ostwald growth significantly occurs.
  • the number of Si particles which satisfy D ⁇ L and L+D>0.04 t in the Si particles in the surface layer and the equivalent circle diameter of each Si particle are increased, whereby 0 ⁇ D 2 ⁇ 0.08 tW is not satisfied.
  • a method for producing the aluminum alloy material used in the present embodiment may be performed according to a usual method, and it is necessary to note the heating conditions described above.
  • An example of the production method in the case of DC casting will be described below.
  • the rate of casting a slab in casting is controlled as described below.
  • the casting rate influences a cooling rate and is therefore set to 20 to 100 min/min.
  • the casting rate is less than 20 mm/min, it is impossible to obtain a sufficient cooling rate, and crystallized products such as Si-based particles and an Al—Fe—Mn—Si-based intermetallic compound are coarsened.
  • the casting rate is more than 100 mm/min, an aluminum alloy material is not sufficiently solidified in casting, and it is impossible to obtain a normal ingot.
  • the casting rate is preferably 30 to 80 mm/min.
  • the casting rate can be adjusted depending on the composition of the produced alloy material in order to obtain the characteristic metal structure of the present embodiment.
  • the cooling rate depends on the cross-sectional shape of the slab, such as a thickness or a width, and a cooling rate of 0.1 to 2° C./s can be achieved in the center of an ingot by setting the casting rate to 20 to 100 mm/min as described above.
  • Such a cooling rate (0.1 to 2° C./s) in the center of an ingot enables the generation of coarse Si particles to be suppressed.
  • the thickness of the ingot (slab) in the DC casting is preferably 700 mm or less.
  • the thickness of the slab is more preferably 500 mm or less.
  • the slab cast by the DC casting method is subjected to a heating step prior to hot rolling, a hot rolling step, a cold rolling step, and an annealing step. Homogenization treatment may be performed after the casting and before the hot rolling.
  • the slab produced by the DC casting method is subjected to the heating step prior to the hot rolling, after the homogenization treatment or without being subjected to the homogenization treatment. It is preferable to perform the heating step according to a usual method so that a heating and retention temperature is in a range of 400 to 570° C., preferably 450 to 520° C., and a retention time is in a range of 0 to 15 hours, preferably 1 to 10 hours, and so that the retention time is not more than 10 hours when heating is performed to 530° C. or more.
  • a retention temperature of less than 400° C. results in the high deformation resistance of the slab in the hot rolling and may cause cracking to occur. In contrast, a retention temperature of more than 570° C. may cause melting to locally occur.
  • a retention time of 0 hours mean that the heating is ended immediately after the heating and retention temperature has been reached.
  • the hot rolling step includes a hot rough rolling stage and a hot finishing rolling stage.
  • a total rolling reduction in the hot rough rolling stage is set to 92 to 97%, and three or more passes at a rolling reduction of 15% or more are included in passes in the hot rough rolling.
  • a coarse crystallized product is generated in a final solidification portion in the slab produced by the DC casting method. Since a crystallized product is sheared and divided into small portions by rolling in a step of making a sheet material, the crystallized product is observed in a particle form after the rolling.
  • the hot rolling step includes: the hot rough rolling stage in which a sheet having a certain thickness is made from the slab; and the hot finishing rolling stage in which a sheet thickness of about several millimeters is achieved.
  • the coarse crystallized product can be finely divided by setting a total rolling reduction in the hot rough rolling stage to 92 to 97%, preferably 94 to 96%, and allowing the hot rough rolling stage to include three or more passes at a rolling reduction of 15% or more, preferably four or more passes at a rolling reduction of 20% or more.
  • Si particles and an Al—Fe—Mn—Si-based intermetallic compound which are crystallized products can be fragmented and can be allowed to be in an appropriate distribution state regulated in the present embodiment.
  • a total rolling reduction of less than 92% in the hot rough rolling stage results in the insufficient effect of the fragmentation of the crystallized product.
  • a total rolling reduction of more than 97% requires the small thickness of the finished sheet in the hot rough rolling, which is difficult for a facility.
  • a method in which the thickness of an original slab is increased to increase the total rolling reduction is also acceptable but is difficult because the thickness exceeds the upper limit value of the thickness of the slab.
  • a rolling reduction in each pass in the hot rough rolling stage also affects the distribution of the crystallized product, and the crystallized product is divided by increasing the rolling reduction in each pass. The case of less than three passes at a rolling reduction of 15% or more in passes in the hot rough rolling stage results in the insufficient effect of the fragmentation of the crystallized product.
  • a rolling reduction of less than 15% is not targeted because the rolling reduction is insufficient, and the crystallized product is not fragmented.
  • the upper limit of the number of passes at a rolling reduction of 15% or more is not particularly regulated but is preferably set to about ten in consideration of productivity and the like.
  • the hot-rolled material is subjected to the cold rolling step after the hot rolling step.
  • the conditions of the cold rolling step are not particularly limited.
  • An annealing step in which the cold-rolled material is annealed is performed during the cold rolling step. This intermediate annealing is performed under the conditions in the ranges of 250 to 450° C. and 1 to 5 hours, preferably 300 to 400° C. and 2 to 4 hours.
  • the rolled material is subjected to final cold rolling to achieve a final sheet thickness.
  • a working rate in the final cold rolling stage is preferably set to about 10 to 30%, more preferably about 12 to 25%.
  • the hot-rolled material may be worked to achieve a final sheet thickness in the cold rolling step and may be subjected to final annealing, or may be subjected to final annealing in an intermediate annealing step after the final cold rolling, similarly in the case of the H1n temper.
  • the continuous casting method is not particularly limited as long as being a method for continuously casting a sheet-shaped ingot, such a twin-roller-type continuous casting rolling method or a twin-belt-type continuous casting method.
  • the twin-roller-type continuous casting rolling method is a method in which molten aluminum is supplied between a pair of water-cooling rolls from a molten metal supply nozzle made of a refractory to continuously cast and roll a thin sheet.
  • a Hunter method, a 3C method, or the like is known as the method.
  • the twin-belt-type continuous casting method is a continuous casting method in which a molten metal is teemed between rotation belts that vertically face each other and are water-cooled to solidify the molten metal by cooling from a belt surface to make a slab, and the slab is continuously drawn from a side opposite to the teeming portion of the belts and wound in a coil form.
  • a Hazelett method or the like is known as the method.
  • a cooling rate in casting in the twin-roller-type continuous casting rolling method is several times to several hundred times higher than that in a semi-continuous casting method.
  • the cooling rate in the case of the semi-continuous casting method is 0.5 to 20° C./s
  • the cooling rate in the case of the twin-roller-type continuous casting rolling method is 100 to 1000° C./s. Therefore, there is a characteristic in that dispersed particles generated in casting are finely and highly densely distributed in comparison with the semi-continuous casting method.
  • the cooling rate in the case of the twin-roller-type continuous casting rolling method is preferably set to 100 to 1000° C./s, and more preferably set to 300 to 900° C./s.
  • a cooling rate of less than 100° C./s precludes obtainment of a metal structure of interest, while a cooling rate of more than 1000° C./s precludes stable production.
  • the rate of a rolled sheet cast by the twin-roller-type continuous casting rolling method is preferably 0.5 to 3 m/min and more preferably 1 to 2 m/min.
  • the casting rate influences a cooling rate.
  • the casting rate is less than 0.5 m/min, it is impossible to obtain such a sufficient cooling rate as described above, and a compound is coarsened.
  • the casting rate is more than 3 m/min, the aluminum alloy material is not sufficiently solidified between the rolls during the casting, and it is impossible to obtain a normal sheet-shaped ingot.
  • the temperature of the molten metal cast by the twin-roller-type continuous casting rolling method is preferably in a range of 650 to 800° C.
  • the temperature of the molten metal is the temperature of a head box just in front of the molten metal supply nozzle.
  • a molten metal temperature of less than 650° C. allows the dispersed particles of a coarse crystallized product to be generated in the molten metal supply nozzle and allows the dispersed particles to be mixed into the ingot, thereby causing the sheet to be cut in the cold rolling.
  • a molten metal temperature of more than 800° C. prevents the aluminum alloy material from being sufficiently solidified between the rolls in the casting, whereby it is impossible to obtain a normal sheet-shaped ingot.
  • the temperature of the molten metal is more preferably 680 to 750° C.
  • the sheet thickness of the sheet-shaped ingot cast by the twin-roller-type continuous casting rolling method is preferably 2 to 10 mm. In the range of the thickness, a homogeneous structure in which the solidification rate of the center of the sheet thickness is high is easily obtained. A sheet thickness of less than 2 mm results in the small amount of aluminum passed through a casting machine per unit time, thereby precluding stable supply of a molten metal in a sheet width direction. In contrast, a sheet thickness of more than 10 mm precludes winding by the rolls.
  • the sheet thickness of the sheet-shaped ingot is more preferably 4 to 8 mm.
  • annealing is performed at 250 to 550° C. for 1 to 10 hours, preferably at 300 to 500° C. for 2 to 8 hours, where a time for which retention at 530° C. or more is performed is in a range of 10 hours or less.
  • the annealing may be performed in any step, except the final cold rolling, in the production step after the casting. It is necessary to perform the annealing one or more times.
  • the upper limit of the number of times of the annealing is preferably three, more preferably two.
  • the annealing is performed for softening the material to facilitate the obtainment of desired material strength in the final rolling.
  • the size and density of the crystallized product and the precipitate in the material, and the amount of the solid solution of an added element can be optimally adjusted by the annealing.
  • tensile strength (TS) before brazing heating becomes high because the material is insufficiently softened.
  • High TS before brazing heating results in poor moldability and therefore in the deterioration of a core dimension, thereby resulting in the deterioration of durability.
  • the annealing is performed at a temperature of more than 550° C., the amount of heat input into the material during the production step is too large, and therefore, the crystallized product and the precipitate are coarsely and sparse distributed.
  • the coarsely and sparse distributed crystallized product and precipitate hardly include a solid-dissolved element and allow the amount of solid solution in the material to be inhibited from decreasing.
  • An annealing time of less than 1 hour allows the above-described effects to be insufficient, and an annealing time of more than 10 hours allows the above-described effects to be saturated and therefore results in economical disadvantage.
  • the fin material according to the present embodiment has the ability of being bonded by heating with a single layer and exhibits the function of generating a liquid phase in the material by heating and of bonding by the liquid phase.
  • a higher temperature at the time of heating results in formation of a larger amount of liquid phase and facilitates security of bondability.
  • the formation of a larger amount of liquid phase facilitates a decrease in the sheet thickness of the fin material and the deformation of the fin material. Therefore, it is important to manage the conditions of the heating for bonding.
  • the heating is performed for a time required for the bonding at a temperature which is not less than a solidus line in which a liquid phase is generated in the fin material according to the present embodiment, which is not more than a liquidus line, and which is less than a temperature at which the generation of the liquid phase in the fin material results in a decrease in strength, thereby making it impossible to maintain a shape.
  • liquid phase ratio the ratio of the mass of a liquid phase generated in the fin material to the total mass of the fin material.
  • a liquid phase ratio of more than 0% is required because it is impossible to perform the bonding unless the liquid phase is generated.
  • a liquid phase ratio of 5% or more is preferred.
  • a liquid phase ratio of more than 35% results in the excessively large amount of generated liquid phase, thereby causing the fin material to be greatly deformed at the time of the heating for bonding and making it impossible to maintain a shape.
  • a liquid phase ratio of 5 to 30% is preferred, and a liquid phase ratio of 10 to 20% is more preferred.
  • a time for which the liquid phase ratio is 5% or more is 30 to 3600 seconds. More preferably, the time for which the liquid phase ratio is 5% or more is 60 to 1800 seconds, resulting in further sufficient filling and reliable bonding.
  • the time for which the liquid phase ratio is 5% or more is less than 30 seconds, the liquid phase may be prevented from being sufficiently filled into a bond portion. In contrast, when the time is more than 3600 seconds, the deformation of the fin material may proceed.
  • the liquid phase moves only in the extreme vicinity of the bond portion, and a time required for the filling does not depend on the size of the bond portion.
  • a bonding temperature may be set at 580 to 640° C., and a retention time at the bonding temperature in this range may be set to 0 to 10 minutes, in the case of the above-described fin material according to the present embodiment.
  • 0 minutes mean that cooling is started immediately after the temperature of a member has reached a predetermined bonding temperature.
  • the above-described retention time is more preferably 30 seconds to 5 minutes.
  • the bonding temperature is more preferably set to 590 to 620° C.
  • the heating conditions may be adjusted depending on composition in order to allow the metal structure of the bond portion to be in a preferred state described later.
  • a liquid phase ratio regulated in the present embodiment can be typically determined by a lever rule on the basis of alloy composition and maximum attainment temperature using an equilibrium diagram.
  • a liquid phase ratio can be determined by using a lever rule with the use of the phase diagram.
  • a liquid phase ratio can be determined using equilibrium calculation phase diagram software.
  • a technique in which a liquid phase ratio is determined by a lever rule with the use of alloy composition and temperature is incorporated into the equilibrium calculation phase diagram software. Examples of the equilibrium calculation phase diagram software include Thermo-Calc, manufactured by Thermo-Calc Software AB.
  • the equilibrium calculation phase diagram software may also be used for simplification because the same result as the result of the determination of a liquid phase ratio by using a lever rule on the basis of the equilibrium diagram is given even if the liquid phase ratio is calculated using the equilibrium calculation phase diagram software.
  • a heating atmosphere in heat treatment is preferably a non-oxidizing atmosphere replaced with nitrogen, argon, or the like; or the like. Further favorable bondability can be obtained by using a non-corrosive flux. Further, heating and bonding can be performed in a vacuum and under reduced pressure.
  • Examples of a method for applying the non-corrosive flux include a method in which a member to be bonded is assembled, followed by sprinkling a flux powder on the member, and a method in which a flux powder is suspended in water, and the flux powder with water is spray-coated.
  • the adhesiveness of the coating can be enhanced by applying a flux powder mixed with a binder such as acryl resin.
  • non-corrosive fluxes used for obtaining the usual functions of the fluxes include: fluoride-based fluxes such as KAlF 4 , K 2 AlF 5 , K 2 AlF 5 .H 2 O, K 3 AlF 6 , AlF 3 , KZnF 3 , and K 2 SiF 6 ; and cesium-based fluxes such as Cs 3 AlF 6 , CsAlF 4 .2H 2 O, and Cs 2 AlF 5 .H 2 O.
  • fluoride-based fluxes such as KAlF 4 , K 2 AlF 5 , K 2 AlF 5 .H 2 O, K 3 AlF 6 , AlF 3 , KZnF 3 , and K 2 SiF 6
  • cesium-based fluxes such as Cs 3 AlF 6 , CsAlF 4 .2H 2 O, and Cs 2 AlF 5 .H 2 O.
  • a crystal particle diameter after bonding and heating is preferably set to 50 ⁇ m or more, and more preferably set to 200 ⁇ m or more, in order to suppress deformation (warpage or buckling) in the heating for bonding.
  • the crystal particle diameter is less than 50 ⁇ m, grain boundary sliding may occur, thereby resulting in significant deformation, in bonding and heating.
  • the crystal particle diameter is 50 ⁇ m or more, deformation in the heating for bonding is suppressed, and therefore, a clearance between the fin material and another member such as a tube is appropriately maintained, whereby bondability can be improved.
  • the upper limit value of the crystal particle diameter is not particularly limited but depends on alloy composition and a production method, and is about 2000 ⁇ m in the present embodiment.
  • the fin material according to the present embodiment has a feature in that a decrease in sheet thickness is suppressed by controlling a metal structure in the vicinity of a surface layer. Such an effect can also be obtained similarly in the case of cladding the fin material according to the present embodiment on another material.
  • a decrease in sheet thickness is up to 8% or less of the thickness of the clad fin material portion according to the present embodiment, thereby therefore achieving the less rate of the decrease in sheet thickness with respect to the sheet thickness of the whole clad material.
  • a cladding ratio is not particularly limited, and may be in a range enabling production. Specifically, the cladding ratio is about 2% to 98%, preferably about 5 to 95%, depending on the sheet thickness of the clad material.
  • clad materials include an aluminum alloy brazing sheet in which the fin material according to the present embodiment is clad as a skin material on one surface or both surfaces of a core material made of an aluminum alloy.
  • a core material made of an aluminum alloy.
  • plural notch grooves 16 opened to penetrate the same positions of a plate-shaped fin material are disposed at a predetermined spacing along each end edge of many sheet-shaped fins 12 which overlap one another at a predetermined spacing, as illustrated in FIGS. 1 and 2 .
  • Collars 20 are formed about the notch grooves 16 so as to come in contact with surfaces of flat tubes 14 including flow passages 15 through which a heat-transfer fluid is allowed to flow.
  • the flat tubes 14 are assembled in the state of extending in the direction of overlapping such sheet-shaped fins 12 by fitting each of the flat tubes 14 into each of the notch grooves 16 at the same positions, bonded, and heated, whereby a heat exchanger 10 is produced.
  • the heat exchanger may be produced by heating and bonding the fin material according to the present embodiment, worked in a wave (corrugated) shape, between the flat tubes which are arranged at a predetermined pacing so that flat portions face each other, and through which the heat-transfer fluid flows.
  • test materials having a thickness of 400 mm, a width of 1000 mm, and a length of 3000 mm were cast by a DC casting method using aluminum alloys having alloy compositions A1 to A23 set forth in Table 1.
  • a casting rate was set to 50 mm/min at a cooling rate set to 1° C./s.
  • “-” indicates a value that is not more than a detection limit, and “balance” includes inevitable impurities.
  • the ingot cast by the DC casting method was faced to have a thickness of 380 mm, then heated to a temperature of 480° C. in a heating and retention step prior to hot rolling, retained at the temperature for 5 hours, and then subjected to a hot rolling step.
  • the ingot was rolled to have a thickness of 3 mm.
  • a total rolling reduction in hot rough rolling in the hot rolling step was 92.5%, and three or more passes at a rolling reduction of 15% or more in each pass in the hot rough rolling were performed.
  • the rolled sheet was rolled to have thickness of 0.09 mm.
  • the rolled material was subjected to an intermediate annealing step at 380° C. for 2 hours and finally rolled to have a final sheet thickness of 0.07 mm in a final cold rolling stage, thereby obtaining a sample material.
  • a working rate in the final cold rolling stage was 22.2%.
  • the test material was subjected to the hot rolling step. In the hot rolling step, the test material was rolled to have a thickness of 3 mm.
  • a total rolling reduction in hot rough rolling in the hot rolling step was 92.5%, and three or more passes at a rolling reduction of 15% or more in each pass in the hot rough rolling were performed.
  • the rolled sheet was rolled to have thickness of 0.09 mm.
  • the rolled material was subjected to an intermediate annealing step at 380° C. for 2 hours and finally rolled to have a final sheet thickness of 0.07 mm in a final cold rolling stage, thereby obtaining a sample material.
  • a working rate in the final cold rolling stage was 22.2%.
  • an ingot with the component of A17 was also cast by a twin-roller-type continuous casting rolling method in a different manner from the manner described above.
  • the temperature of a molten metal cast by the twin-roller-type continuous casting rolling method was 650 to 800° C., and the thickness of a cast metal sheet was 6 mm.
  • a casting rate was set to 700 mm/min at a cooling rate set to 200° C./s.
  • the obtained sheet-shaped ingot was cold-rolled to 0.7 mm, subjected to intermediate annealing at 480° C. for 5 hours, then cold-rolled to 0.09 mm, subjected to the second annealing at 380° C. for 2 hours, and then cold-rolled to 0.070 mm, thereby obtaining a sample material.
  • C1, C2, and C3 in Table 1 are cast by a DC casting method in a manner similar to the manner for Al to A23 and subjected to a heating and retention step prior to hot rolling. Then, C1 and C3 were put on both surfaces of C2, respectively, at a cladding ratio of 10% and hot-clad-rolled to produce clad materials CL1 (C1/C2/C1) and CL2 (C3/C2/C3).
  • a hot clad rolling step the rolling was performed to achieve a thickness of 3 mm.
  • a total rolling reduction in hot rough rolling in the hot clad rolling step was 93.8%, and three or more passes at a rolling reduction of 15% or more in each pass in the hot rough rolling were performed.
  • the rolled sheet was rolled to have thickness of 0.09 mm. Further, the rolled material was subjected to an intermediate annealing step at 380° C. for 2 hours and finally rolled to have a final sheet thickness of 0.07 mm in a final cold rolling stage, thereby obtaining a sample material. A working rate in the final cold rolling stage was 22.2%.
  • productability in a production process was evaluated.
  • a case in which no problem occurred and a favorable sheet material or slab was obtained in the production process when the sheet material or slab was produced was evaluated as “good”, while a case in which cracking occurred in casting or a case in which the generation of a big crystallized product in the casting caused rolling to be precluded and productability was problematic was evaluated as “fair”.
  • the rate of decrease in the sheet thickness of the sample material in the case of heating at a temperature equivalent to a bonding and heating temperature was evaluated.
  • fin sheet thicknesses before and after the heating were measured with a micrometer.
  • the rate of decrease in sheet thickness was calculated with the arithmetic mean value of measured sheet thicknesses at the same three or more positions before and after the heating in order to measure a difference before and after the heating.
  • each sample material was cut to have a length of 100 mm and a width of 20 mm, a hole was made in one end in a longitudinal direction, a stainless steel wire was passed through the hole, and the sample material was heated to 600° C.
  • a decrease in sheet thickness set forth in Table 2 is defined as a value obtained by discarding digits to the right of the decimal point of an actually determined numerical value.
  • each test material was cut to have a width of 20 mm and a length of 100 mm, and a fin material including notches having a width of 2 mm and a length of 15 mm at a pitch of 10 mm was made by pressing.
  • collars were perpendicularly cut and raised to have a height of 0.5 mm in the notches of the fin material.
  • Such twenty fin materials were aligned in parallel at a pitch of 2 mm so that the positions of the notches were uniform.
  • Multi-port tubes having the composition of B1 set forth in Table 1 were inserted into the notches.
  • Such a multi-port tube was set to have a thickness of 1.98 mm, a width of 20 mm, and a length of 60 mm.
  • the twenty fins and the ten multi-port tubes were incorporated in combination into a stainless steel jig to produce a test piece (mini core).
  • the mini core produced as described above was dipped in a 10% suspension of a non-corrosive fluoride-based flux, dried, then heated to 600° C. in a nitrogen atmosphere, and retained for 3 minutes, thereby heating and bonding the fin materials and the multi-port tubes.
  • the corrosion resistance of the mini core produced as described above was evaluated.
  • a CASS test was conducted for 500 h to confirm the corrosion states of the multi-port tubes.
  • the depth of the corrosion of a maximum corrosion portion was measured by a focal method with a microscope, a depth of 50 ⁇ m or less was regarded as excellent, a depth of more than 50 ⁇ m and 150 ⁇ m or less was regarded as good, a depth of more than 150 ⁇ m and 300 ⁇ m or less was regarded as fair, and a depth of more than 300 ⁇ m was regarded as poor.
  • the results are set forth in Table 2.
  • the Si component in the fin material was less than 1.50%, and therefore, an insufficient liquid phase ratio and bad bondability were exhibited.
  • Comparative Example 3 the Si component in the fin material was more than 5.00%, therefore, the metal structure did not satisfy the regulations, and a decrease in sheet thickness of more than 8% and bad bondability were exhibited.
  • the Zn component in the fin material was more than 6.00%, and therefore, deteriorated self-corrosion resistance and bad corrosion resistance were exhibited.
  • an aluminum alloy fin material which has high bondability and high rigidity, of which the thickness can be reduced, and of which the reduction in the weight is achieved, a brazing sheet in which the aluminum alloy fin material is used, and a heat exchanger in which the fin material or the brazing sheet is used in a fin are provided as described above.

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US16/091,776 2016-04-12 2017-04-12 Aluminum alloy fin material, aluminum alloy brazing sheet, and heat exchanger Abandoned US20190162492A1 (en)

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JP2016079933 2016-04-12
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JP2017060744A JP6909028B2 (ja) 2016-04-12 2017-03-27 アルミニウム合金製フィン材及びこれを用いたアルミニウム合金製ブレージングシート、ならびに、当該フィン材又はブレージングシートをフィンに用いた熱交換器
PCT/JP2017/015001 WO2017179625A1 (ja) 2016-04-12 2017-04-12 アルミニウム合金製のフィン材、アルミニウム合金製のブレージングシート、および熱交換器

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JP7469072B2 (ja) * 2020-02-28 2024-04-16 株式会社神戸製鋼所 アルミニウム合金鍛造材及びその製造方法
JP7519238B2 (ja) 2020-09-02 2024-07-19 株式会社Uacj アルミニウム合金押出チューブ及び熱交換器
CN113174548B (zh) * 2021-03-16 2022-11-18 株式会社Uacj 一种钎焊用单层铝合金翅片材料及其制造方法
CN115927923B (zh) * 2022-11-30 2024-07-16 上海华峰铝业股份有限公司 一种单层可钎焊铝合金材料及其制造方法

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