WO2019102915A1 - Ailette en aluminium à excellent caractère hydrophile après brasage, et échangeur de chaleur et son procédé de production - Google Patents

Ailette en aluminium à excellent caractère hydrophile après brasage, et échangeur de chaleur et son procédé de production Download PDF

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Publication number
WO2019102915A1
WO2019102915A1 PCT/JP2018/042108 JP2018042108W WO2019102915A1 WO 2019102915 A1 WO2019102915 A1 WO 2019102915A1 JP 2018042108 W JP2018042108 W JP 2018042108W WO 2019102915 A1 WO2019102915 A1 WO 2019102915A1
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WIPO (PCT)
Prior art keywords
brazing
tube
aluminum
heat exchanger
fin
Prior art date
Application number
PCT/JP2018/042108
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English (en)
Japanese (ja)
Inventor
翔 石上
淑夫 久米
Original Assignee
三菱アルミニウム株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2018144415A external-priority patent/JP7209487B2/ja
Application filed by 三菱アルミニウム株式会社 filed Critical 三菱アルミニウム株式会社
Priority to CN201880075212.2A priority Critical patent/CN111344530A/zh
Publication of WO2019102915A1 publication Critical patent/WO2019102915A1/fr

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    • 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
    • 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
    • B23K1/19—Soldering, e.g. brazing, or unsoldering taking account of the properties of the materials to be soldered
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
    • F24F1/06—Separate outdoor units, e.g. outdoor unit to be linked to a separate room comprising a compressor and a heat exchanger
    • F24F1/14—Heat exchangers specially adapted for separate outdoor units
    • F24F1/18—Heat exchangers specially adapted for separate outdoor units characterised by their shape
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B39/00—Evaporators; Condensers
    • 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
    • F28D1/04—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 tubular conduits
    • F28D1/053—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 tubular conduits the conduits being straight
    • 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
    • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • F28F13/18—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by applying coatings, e.g. radiation-absorbing, radiation-reflecting; by surface treatment, e.g. polishing
    • 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
    • F28F19/02—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings
    • F28F19/06—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings 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
    • 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

Definitions

  • the present invention relates to an aluminum fin and a heat exchanger excellent in hydrophilicity after brazing, and a method for producing the same.
  • Priority is claimed on Japanese Patent Application Nos. 2017-226238 filed on November 24, 2017, and Japanese Patent Application No. 2018-144415 filed in July 31, 2018, the contents of which are incorporated herein by reference. Is incorporated herein by reference.
  • a heat exchanger in which a copper tube and an aluminum fin are mechanically joined is widely used as a heat exchanger for air conditioning such as an air conditioner.
  • air conditioning such as an air conditioner.
  • Aluminum is excellent in lightness, processability and thermal conductivity, is recyclable, and is inexpensive.
  • Patent Document 1 As an example of this kind of air conditioning heat exchanger, as described in Patent Document 1 below, there is a fixed space between the first header manifold and the second header manifold arranged on the left and right.
  • a heat exchanger is known which is provided with a plurality of aluminum alloy flat tubes arranged side by side, and corrugated fins meandering vertically between the upper and lower flat tubes.
  • the heat transfer portion of the fin is disposed between flat tubes arranged in the upper and lower direction, the air passage is divided between the flat tubes, and the air flowing through the air passage and the flat tube Heat exchange is performed with the fluid flowing inside the
  • a flux composition consisting of a synthetic resin containing a polymer or copolymer of methacrylic acid ester as a main component, a flux for brazing, and an organic solvent in order to suppress retention of dew condensation water to an extruded porous flat tube made of aluminum alloy.
  • the flat tube for heat exchangers which covered the object on the surface is described in the following patent documents 2.
  • an object of the present invention is to provide an aluminum fin and a heat exchanger excellent in hydrophilicity after brazing and a method for producing the same.
  • the aluminum fin of the present invention is an aluminum fin to be brazed to an aluminum tube provided with a refrigerant flow channel inside, and is hydrophilic having a boehmite film with a thickness of 100 to 10000 ⁇ on at least one of the front and back surfaces. It is characterized by having a film.
  • the color value of the surface provided with the hydrophilic film is preferably L: 70 to 100, a: -3 to +5, b: -3 to +10.
  • the water contact angle after the brazing heat treatment is preferably 40 ° or less on the surface provided with the hydrophilic film.
  • the heat exchanger of the present invention can adopt a configuration in which any of the aluminum fins described above is brazed to a tube made of aluminum or an aluminum alloy.
  • a plurality of tubes made of aluminum or an aluminum alloy in which a plurality of the aluminum fins described above are arranged at predetermined intervals from one another and the plurality of aluminum fins are inserted or penetrated. May be brazed to the aluminum fin, and the plurality of tubes may be brazed individually to the header pipe.
  • a brazing coating containing Si powder and a Zn-containing flux is formed on the outer surface of the tube constituting the tube before brazing, and the brazing coating is used after the brazing.
  • a configuration in which the brazing material layer is formed can be adopted.
  • a method of manufacturing a heat exchanger according to the present invention is a method of manufacturing a heat exchanger by brazing a tube having a refrigerant flow passage inside to the aluminum fin described in any of the above, A brazed coating containing Si powder and a Zn-containing flux is formed on the outer surface of the tube constituting the tube, and Si and Zn in the brazed coating are diffused to the tube side by heat treatment at the time of brazing. It is characterized in that a sacrificial anode layer in which Zn is diffused on the outer surface side is formed.
  • the aluminum fin according to the present invention by forming a boehmite film of a specified thickness as a hydrophilic film before brazing, the aluminum fin can be provided with excellent hydrophilicity even after brazing. At the same time, it is possible to provide an aluminum fin having a beautiful appearance without causing discoloration on the surface of the hydrophilic film even through heating by brazing.
  • the heat exchanger according to the present invention since it is configured to be joined to the tube by brazing using an aluminum fin of a type in which a hydrophilic film is provided in advance corresponding to the precoated fin, the manufacture using a precoated fin It is possible to provide a heat exchanger that can be manufactured by the same process as the process, and is provided with aluminum fins to which good hydrophilicity is imparted even after brazing, and the appearance of the fins is also good.
  • FIG. 1 It is a perspective view showing a heat exchanger of a 1st embodiment.
  • FIG. 1 it is sectional drawing which took the cross section along the surface orthogonal to the length direction of a tube.
  • FIG. 1 it is sectional drawing which took the longitudinal cross section along the length direction of a tube, and shows the state before a brazing process.
  • FIG. 2 is a cross-sectional view of the heat exchanger shown in FIG. 1 taken along the longitudinal direction of the tube, showing a state after a brazing process.
  • It is a front view which shows the heat exchanger of 2nd Embodiment.
  • It is a partial expanded sectional view of the heat exchanger of 2nd Embodiment.
  • It is a fragmentary sectional view showing a heat exchanger assembly before brazing a heat exchanger of a 2nd embodiment.
  • FIG. 1 is a perspective view showing the heat exchanger 11 of the first embodiment.
  • the heat exchanger 11 of the first embodiment is used for applications such as heat exchangers for indoor and outdoor units in room air conditioners, outdoor units for HVAC (Heating Ventilating Air Conditioning), and heat exchangers for automobiles. Is an all-aluminum heat exchanger.
  • the heat exchanger 11 is parallel to and spaced from each other in the vertical direction between a pair of header pipes 14 and a pair of header pipes 14 disposed in parallel and spaced apart in the left and right direction as shown in FIG.
  • a plurality of flat type tubes 22 joined substantially at right angles to the header pipe 14 and the outer surface (upper surface or lower surface) 12b of the tube 12 constituting these tubes 22 are brazed to dissipate heat from the outside air
  • a plurality of fins (aluminum fins) 13 are provided.
  • a supply pipe 15 for supplying the refrigerant to the tube 22 is connected to the upper end of one of the pair of left and right header pipes 14 via the header pipe 14. Further, to the lower end portion of the other header pipe 14, a recovery pipe 16 for recovering the refrigerant passing through the tube 22 is connected.
  • the tube 22, the fins 13, the header tube 14, the supply tube 15, and the recovery tube 16 are all made of aluminum or an aluminum alloy.
  • FIG. 2 is a partial cross-sectional view of the heat exchanger 11 taken along the plane orthogonal to the longitudinal direction of the tube 22.
  • a plurality of (six in the present embodiment) refrigerant flow paths 12 a are formed in the inside of the tubular body 12 constituting the tube 22 along the width direction.
  • a plurality of notches 19 having a shape corresponding to the cross-sectional shape of the tube 22 are formed at predetermined intervals in the vertical direction.
  • the tubes 22 are respectively fitted in the notches 19 and fixed by brazing.
  • FIG. 3 and 4 are partial cross-sectional views of the heat exchanger 11 taken along the longitudinal direction of the tube 22 in the longitudinal direction, FIG. 3 shows the condition before the brazing step, and FIG. 4 is the brazing step Indicates the later state.
  • a plurality of fins 13 are arranged in parallel along the longitudinal direction of the tube 22, and the tube 22 is inserted into the notch 19.
  • the plurality of fins 13 are arranged in parallel parallel to each other at a constant distance.
  • the fin 13 has a bent portion 20 which is bent on one side in the thickness direction of the fin 13 along the outer surface 12 b of the tube 22 at the periphery of the notch 19.
  • the bent portion 20 can be formed, for example, by burring.
  • the tubes 22 and the fins 13 are arranged such that the tubes 22 pierce the plurality of fins 13 arranged at regular intervals, and the tubes 22 are fitted in the notches 19 of the fins 13 and fixed by brazing. .
  • the gap between the bent portion 20 formed in the notch portion 19 of the fin 13 and the upper surface or the lower surface of the tube 22 is preferably 10 ⁇ m or less.
  • the tube 22 is inserted through the notch 19.
  • the slit 13 is provided with a slit-like through hole, and the tube 22 is inserted through the through hole. It is good also as composition.
  • the fins 13 have a plate-like base 3 made of aluminum or an aluminum alloy, and a hydrophilic film 1 provided on the first surface 3 a and the second surface 3 b of the base 3.
  • the substrate 3 is made of an alloy mainly composed of a pure aluminum such as JIS 1050 series or an aluminum alloy of JIS 3003 series.
  • the base material 3 may be made of an aluminum alloy in which about 2% by weight of Zn is added to an aluminum alloy of JIS 3003 series.
  • the base material 3 is preferably made of a material that has a pitting potential of a weir more than the pitting potential of the tube 12 constituting the tube 22.
  • the corrosion of the tubular body 12 may lead to the leakage of the refrigerant.
  • the base material 3 is produced by melting an aluminum alloy having the above composition by a conventional method, and is processed through a hot rolling process, a cold rolling process, a pressing process and the like.
  • the manufacturing method of the base material 3 is not specifically limited in this invention, A well-known manufacturing method can be employ
  • the fins 13 have the hydrophilic film 1 on the first surface 3 a and the second surface 3 b of the base material 3 and the other peripheral surfaces.
  • the hydrophilic film 1 is a boehmite film having a thickness of about 100 ⁇ to 10000 ⁇ .
  • the boehmite film is a film formed by immersing aluminum or an aluminum alloy in high temperature water of 90 to 100 ° C. or holding it in pressurized steam.
  • High temperature water can be pure water, but may be water obtained by adding a small amount of ammonia water to pure water. Alternatively, deionized water may be used, and an additive such as triethanolamine may be added to adjust the pH to be weakly alkaline to promote growth of the boehmite film.
  • the boehmite film can also be obtained by applying an alkaline or neutral paint to the base material 3 of aluminum fin and drying and then washing with water or washing with water.
  • the hydrophilic film 1 made of a boehmite film is a film that can be called a precoat film formed on the base 3 of the fins 13 before the brazing process.
  • the boehmite film preferably exhibits the desired hydrophilicity after brazing, has no adverse effect on the brazeability, and has a thickness of 100 ⁇ to 10000 ⁇ as described above so as not to change color after brazing.
  • the thickness of the boehmite film is less than 100 ⁇ , the contact angle with water after repeated dry and dry tests after brazing worsens, and when the thickness of the boehmite film exceeds 10000 ⁇ , the brazing film described later is used. There is a problem that the brazability of the case is reduced.
  • the thickness of the boehmite film is preferably in the range of 1000 to 7000 ⁇ , more preferably 2000 to 5250 ⁇ , and still more preferably in the range of 2000 to 3500 ⁇ , in order to achieve the most excellent water contact angle and the excellent brazing property.
  • the tube 22 has a tube 12 and a brazing material layer 5 formed on the outer surface (upper surface or lower surface) 12 b of the tube 12.
  • the pipe body 12 is a flat multi-hole pipe in which a plurality of refrigerant channels 12a are formed inside as shown in FIG. Moreover, as a tube, the tube produced by bend
  • the pipe body 12 is made of, for example, an alloy mainly composed of a pure aluminum such as JIS 1050 series or an aluminum alloy of JIS 3003 series.
  • the tube body 12 is preferably made of a material that has a pitting potential that is nobler than the pitting potential of the base material 3 of the fillet 5A and the fin 3 formed through the brazing step. Thereby, the corrosion of the base material 3 of the fillet 5A and the fins 13 is started before the corrosion of the tubular body 12 is started, and the corrosion of the tubular body 12 can be delayed.
  • Si powder 1.0 to 5.0 g / m 2 and Zn-containing fluoride system on a part of the outer surface 12 b to which the fins 13 are joined.
  • the brazing material layer 5 of the tube 22 is located between the portion (facing surface 20 a) facing the tube 22 of the bent portion 20 of the fin 13 and the tube 22 .
  • the brazing material layer 5 is cooled after heating (brazing step) at around 600 ° C. to solidify in a state of being filled between the facing surface 20 a and the tube 22, and as shown in FIG. As a brazing material layer), the fins 13 and the tube 22 are joined by brazing.
  • the outer surface 12b of the tube 12 has flat surface (upper surface) 6A and back surface (lower surface) 6B, and first and second side surfaces 6C and 6D adjacent to the surface 6A and back surface 6B. It consists of The first side face 6C is located on the opening side of the notch 19 of the fin 13 and is open to the outside. The second side face 6D is located on the opposite side of the first side face 6C and is disposed so as to be surrounded by the notch 19.
  • the brazing material layer 5 is formed, as an example, in a region of the outer surface 12 b of the tube 12 in contact with the fins 13, that is, on the surface 6 A and the back surface 6 B of the tube 12.
  • Si and Zn contained in the brazing material layer 5 are diffused to the surface of the tube 12 at the brazing temperature on the surface 6A and the back surface 6B of the tube 12 after brazing, and the surface layer portion of the tube 12 is A sacrificial anode layer containing Si and Zn is formed.
  • the composition constituting the brazing material layer 5 will be described below.
  • ⁇ Si powder> The Si powder reacts with Al constituting the tube body 12 of the tube 22 to form a solder for joining the fins 13 and the tube 22, but at the time of brazing, the Zn-containing flux and the Si powder melt to form a solder.
  • the Zn in the flux uniformly diffuses in the wax solution and spreads uniformly on the surface of the tube 12. Since the diffusion rate of Zn in the liquid phase brazing liquid is significantly larger than the diffusion rate in the solid phase, this causes uniform Zn diffusion, and the Zn concentration in the surface direction of the surface of the tubular body 12 becomes substantially uniform.
  • Si is eutectic with Al to lower the melting point, so that Zn diffuses to the eutectic composition on the surface of the tube 12
  • a sacrificial anode layer of a predetermined thickness is formed on the surface of the tube 12. The formation of the sacrificial anode layer can improve the corrosion resistance of the tube 22.
  • Si powder application amount 1.0 to 5.0 g / m 2 > If the coating amount of Si powder is less than 1.0 g / m 2 , there is a possibility that the wax formation may be insufficient, and if the coating amount exceeds 5.0 g / m 2 , the melting amount of the tube increases and the tube Is not preferable because the wall thickness of the Therefore, the content of the Si powder in the brazing material layer 5 is preferably 1.0 to 5.0 g / m 2 .
  • ⁇ Si powder particle size Maximum particle size: D (99): 30 ⁇ m or less> If the particle size of the Si powder is 30 ⁇ m or less at D (99), it is possible to form a uniform sacrificial anode layer, but if it exceeds 30 ⁇ m, deep erosion locally occurs and a uniform sacrificial anode layer is formed. May not be able to form Therefore, the particle size of the Si powder is preferably 30 ⁇ m or less at the maximum particle size D (99).
  • D (99) is the particle size of the particle
  • the Zn-containing flux has an effect of forming a sacrificial anode layer composed of a Zn diffusion layer on the surface of the tubular body 12 at the time of brazing, and improving the pitting resistance.
  • the oxide film on the outer surface of the tubular body 12 is destroyed, spreading of the brazing, and promoting the wetting to improve the brazing property. Since this Zn-containing flux has a higher activity than a flux not containing Zn, good brazability can be obtained even using a relatively fine Si powder.
  • the Zn-containing flux one or more of KZnF 3 , ZnF 3 and ZnCl 2 can be used.
  • a non-Zn containing flux may be added to the Zn containing flux.
  • a fluoride-based flux or a potassium fluoroaluminate-based flux is a flux containing KAlF 4 as a main component, and various compositions to which additives are added are known. Examples thereof include those having a composition of K 3 AlF 6 + KAlF 4 , Cs (x) K (y) F (z), and the like.
  • a fluoride-based flux for example, a potassium fluoroaluminate-based flux
  • a fluoride to which a fluoride such as LiF, KF, CaF 2 , AlF 3 , or K 2 SiF 6 is added can also be used.
  • a fluoride-based flux for example, a potassium fluoroaluminate-based flux
  • a fluoride-based flux for example, a potassium fluoroaluminate-based flux
  • the coating amount of the Zn-containing fluoride flux is preferably 3.0 to 20.0 g / m 2 .
  • the Zn-containing fluoride flux can use KZnF 3 as an example.
  • the aforementioned non-Zn-containing flux can be added in addition to the Zn-containing flux.
  • the brazing material layer 5 can contain a binder in addition to the Si powder and the Zn-containing fluoride flux.
  • a binder acrylic resin can be mentioned suitably.
  • the binder functions to fix the Si powder and the Zn-containing flux necessary for forming the sacrificial anode layer on the surface 6A and the back surface 6B of the tube 12. However, if the coating amount of the binder is less than 0.5 g / m 2 , At the time of brazing, Si powder or Zn flux may fall out of the tube 12, and a uniform sacrificial anode layer may not be formed.
  • the coating amount of the binder exceeds 8.5 g / m 2 , the binder residue may deteriorate the brazing property, and a uniform sacrificial anode layer may not be formed. Therefore, the coating amount of the binder is preferably 0.5 to 8.5 g / m 2 .
  • the binder usually evaporates by heating at the time of brazing.
  • the method for forming the brazing material layer 5 comprising Si powder, flux and binder is not particularly limited in the present invention, and spray method, shower method, flow coater method, roll coater method, brush coating method, immersion method, static method It can be carried out by an appropriate method such as an electrocoating method.
  • the formation region of the brazing material layer 5 may be the whole or a part of the surface 6A, the back surface 6B, and the second side surface 6D of the tube 12.
  • the brazing material layer 5 is not formed on the first side face 6C in the tube body 12 of the present embodiment, the pipe body 12 may be partially formed on the first side face 6C depending on the application method. The present invention does not exclude such.
  • the tube 22 and the fins 13 are prepared.
  • the fins 13 have the hydrophilic film 1 formed on the entire surface including the first surface 3 a and the second surface 3 b of the base material 3.
  • a boehmite film having a thickness of 100 to 4000 ⁇ is formed on the entire surface of the fins 13 by the method of holding the fins 13 in the high temperature water described above.
  • the notch portion 19 and a bent portion 20 at the periphery thereof are formed in the fin 13.
  • a tube in which the brazing material layer 5 is formed in advance on a part of the outer surface 12 b of the tubular body 12 is prepared.
  • a plurality of fins 13 are arranged in parallel, and the tube 22 is inserted into the notch 19.
  • a brazing step of heating to a temperature above the melting point of the brazing material layer 5, for example, 580 to 620 ° C. is performed.
  • the brazing material layer 5 formed on the outer surface 12 b of the tube 12 melts and becomes brazing liquid.
  • the wax flows into the gap between the facing surface 20a of the bent portion 20 of the fin 13 and the outer surface 12b of the tube 12 by capillary force to fill the gap.
  • the brazing liquid solidifies and forms fillets 5A (brazing material layer).
  • the tube 22 and the fin 13 are joined by the fillet 5A.
  • the brazing material layer 5 is melted by heating to an appropriate temperature in an appropriate atmosphere such as an inert atmosphere.
  • an appropriate atmosphere such as an inert atmosphere.
  • the activity of the flux is increased, and in addition to the diffusion of Zn in the flux to the thickness direction of the brazing material (base 3 of the fin 13), the surfaces of both the brazing material and the brazing material Destroys the oxide film of the metal and promotes the wetting between the brazing material and the brazing material.
  • a portion of the aluminum alloy matrix constituting the tube body 12 of the tube 22 reacts with the composition of the brazing material layer 5 to be brazed, and the tube body 12 of the tube 22 and the fins 13 are brazed .
  • Zn in the flux is diffused by brazing to form a sacrificial anode layer which is wrinkled more than the inside of the tubular body 12.
  • ⁇ Effect >> According to the structure of this embodiment, good brazing is performed, and a fillet 5A (brazing material layer) of a sufficient size is formed between the tube body 12 and the fin 13.
  • the fillet 5A has a lower pitting potential than the tube 12 and the fins 13. Therefore, it can corrode preferentially as compared with the tube body 12 and the fins 13, and can delay pitting corrosion of the tube body 12 and the fins 13.
  • the hydrophilic film 1 made of a boehmite film remains, and the fins 13 can be provided with hydrophilicity.
  • the hydrophilic film 1 made of a boehmite film which has been subjected to the heat treatment process at the time of brazing is formed, so the hydrophilicity of the fin 13 can be increased.
  • the hydrophilic film 1 made of a boehmite film can maintain its hydrophilicity even through a heating process at a temperature of about 600 ° C. at the time of brazing. Therefore, the hydrophilic film 1 can be formed by a precoating process which is previously formed on the base material 3 of the fins 13 before the heat exchanger 11 is assembled. Since the process of forming a hydrophilic film by post coating after brazing is not necessary, the heat exchanger 11 with a simplified manufacturing process can be provided.
  • the brazing material layer 5 for brazing is provided on the outer surface such as the front surface or the back surface of the tube 22.
  • the brazing material layer 5 is omitted and the brazing of the tube 22 and the fins 13 is performed.
  • a placement bra may be placed around the portion to be joined and a brazed structure may be adopted using the placement bra.
  • the tube 22 and the fin 13 may be brazed and joined by melting the set wax by heating at the time of brazing and distributing the molten solder to the boundary portion between the tube 22 and the fin 13.
  • the fins 13 may be formed of a brazing sheet having a two-layer structure including a core layer and a brazing material layer, and the tube 22 may be configured without the brazing material layer.
  • the above-mentioned boehmite layer can be provided on one side or both sides of the core layer.
  • the fins 13 are formed from a brazing sheet of a three-layer structure (a core material + a three-layer structure with a brazing material layer on both sides provided with a boehmite layer) in which a brazing material layer provided with a boehmite layer on both surfaces of a core material layer It can also be done.
  • the core material is, by mass%, Mn: 0.5 to 2.0%, Si: 1.3% or less, Fe: 0.25% or less, Cu: 0.5%
  • the brazing material layer contains Si: 5.0-13.0% by mass%, the balance
  • a combination of Al and an aluminum alloy having a composition of unavoidable impurities can be exemplified.
  • FIG. 5 is a front view showing a second embodiment of a heat exchanger to which corrugated fins are applied.
  • the heat exchangers 30 according to the second embodiment are parallel to each other with the header pipes 31 and 32 disposed in parallel and spaced apart in the left and right direction and spaced apart from each other.
  • a plurality of flat tubes 33 joined at right angles to the header pipes 31 and 32 and corrugated fins (corrugated fins) 34 attached to the respective tubes 33 are mainly constituted.
  • the header pipes 31, 32, the tubes 33 and the fins 34 are made of an aluminum alloy.
  • the aluminum alloy which comprises the tube 33 can apply the aluminum alloy equivalent to the aluminum alloy which comprises the tube 22 of the heat exchanger 11 of 1st Embodiment.
  • the aluminum alloy which comprises the fin 34 can apply the aluminum alloy equivalent to the aluminum alloy which comprises the fin 13 of the heat exchanger 11 of 1st Embodiment.
  • a plurality of slits 36 are formed on the opposite side surfaces of the header pipes 31 and 32 at regular intervals in the longitudinal direction of each pipe, and the end of the tube 33 is inserted through the opposed slits 36 of the header pipes 31 and 32
  • a tube 33 is installed between the header pipes 31 and 32.
  • fins 34 are disposed between a plurality of tubes 33, 33 installed at a predetermined interval between the header pipes 31, 32, and these fins 34 are brazed to the front side or the back side of the tubes 33.
  • the first fillet portion 38 is formed of brazing material at a portion where the end of the tube 33 is inserted into the slit 36 of the header pipe 31, 32, and the tube 33 is formed relative to the header pipes 31, 32.
  • the second fillet portion 39 is formed by the brazing material generated in the portion between the apexes of the waves facing the front or back of the adjacent tube 33 and the surface of the tube 33
  • Corrugated fins 34 are brazed to the side and back side.
  • the fins 34 have a plate-like base made of aluminum or an aluminum alloy, and a hydrophilic film provided on the first side and the second side of the base. doing.
  • the hydrophilic film of this example is composed of a hydrophilic film equivalent to the hydrophilic film 1 applied in the previous embodiment.
  • the heat exchanger 30 of the present embodiment assembles the header pipes 31 and 32 with the plurality of tubes 33 and the plurality of fins 34 installed between them to form the heat exchanger assembly 41 as shown in FIG. , It is manufactured by heating and brazing.
  • the Zn diffused layer 42 is formed in the surface side and back surface side of the tube 33 by the heating at the time of brazing.
  • a brazing coating film 37 having the same composition as the brazing material layer 5 described above is applied on the front and back surfaces to which the fins 34 are joined.
  • the tube 33 is formed of a flat multi-hole tube equivalent to the tube 22 described above, and a plurality of refrigerant passages 33C are formed therein, and a flat surface (upper surface) 33A and a back surface (lower surface) 33B, and these surfaces 33A and a side surface adjacent to the back surface 33B.
  • the aluminum alloy constituting the header pipes 31 and 32 is preferably an Al-Mn based aluminum alloy.
  • Mn 0.05 to 1.50%
  • Cu 0.05 to 0.8%
  • Zr 0.05 to 0.15% as other elements. it can.
  • FIG. 7 is a heat exchanger assembly 41 which shows the state which assembled the header pipe 31, 32, the tube 33, and the fin 34 using the tube 33 which apply
  • FIG. 7 is a partial enlarged view of FIG. 6 and shows the state before heat brazing.
  • the tube 33 is inserted into and attached to a slit 36 provided at one end of the header pipe 31. Further, a brazing material layer 43 is provided on the surface side of the core material 31A of the header pipes 31, 32.
  • heat exchanger assembly 41 consisting of header pipes 31 and 32, tube 33 and fins 34 assembled as shown in FIG. 7 is heated to a temperature above the melting point of the brazing material in a heating furnace etc. and cooled after heating, After the material layer 43 and the coating film for brazing 37 melt and solidify, as shown in FIG. 6, the header pipe 31 and the tube 33, and the tube 33 and the fin 34 are respectively joined, and the heat of the structure shown in FIGS. The exchanger 30 is obtained. At this time, the brazing filler metal layer 43 on the inner peripheral surface of the header pipes 31 and 32 melts and flows near the slits 36 to form the first fillet portion 38 and the header pipes 31 and 32 and the tube 33 are joined. .
  • the coating films 37 for brazing on the front and back surfaces of the tube 33 are melted to become Al-Si brazing or Al-Si-Zn brazing, and flow near the fins 34 by capillary force to form the second fillet portion 39
  • the tube 33 and the fin 34 are joined.
  • the brazing material layer 43 provided on the surface of the header pipes 31 and 32 slightly remains on the surface after brazing.
  • the coating film 37 for brazing and the brazing material layer 43 are dissolved by heating to a suitable temperature in a heating furnace or the like in an appropriate atmosphere such as an inert atmosphere. Then, the activity of the flux increases, and Zn in the flux precipitates on the surface or lower surface of the brazing material (tube 33) and diffuses in the thickness direction, and the brazing material and the brazing material The oxide film on both surfaces is destroyed to promote wetting between the brazing material and the brazing material.
  • the conditions for brazing are not particularly limited.
  • the inside of the heating furnace is a nitrogen atmosphere, and the heat exchanger assembly 41 is heated to a brazing temperature (actual temperature) of 580 to 620 ° C. at a heating rate of 5 ° C./min or more, and the brazing temperature is 30 seconds or more
  • the temperature may be maintained and the cooling rate from the brazing temperature to 400 ° C. may be 10 ° C./min or more.
  • a region where Zn in the flux is diffused by brazing on the upper and lower surfaces of the tube 33, and a Zn diffusion layer 42 is formed on the surface or lower surface of the tube 33, and Zn is diffused on the surface or lower surface of the tube Is more wrinkled than the inner side in the thickness direction of the tube 33 (the area not receiving the diffusion of Zn).
  • the inner side in the thickness direction of the tube 33 indicates a region deeper in the thickness direction of the tube 33 than the surface region or the back surface region of the tube 33 in which the Zn diffusion layer 42 is formed.
  • a hydrophilic film composed of a boehmite film having a thickness of about 100 ⁇ to about 4000 ⁇ is formed on both surfaces of the fin 34. For this reason, hydrophilicity equivalent to the above-mentioned heat exchanger 11 can be acquired. That is, since the hydrophilic film which consists of a boehmite film which passed through the heat treatment process at the time of brazing is formed on the fin 34 after brazing shown in FIG. 5 and FIG. it can.
  • the hydrophilic film made of the above-described boehmite film can maintain its hydrophilicity even through a heating process at a temperature of around 600 ° C. at the time of brazing.
  • the hydrophilic coating can be formed by a precoating step which is preformed on the base of the fins 34 prior to assembly of the heat exchanger 30. Since the process of forming a hydrophilic film by post coating after brazing is not necessary, the heat exchanger 30 with a simplified manufacturing process can be provided. In addition, the heat exchanger 30 can obtain excellent corrosion resistance as in the heat exchanger 11 of the previous embodiment.
  • the brazing material layer 37 for brazing is provided on the outer surface such as the upper surface or the lower surface of the tube 33.
  • the material layer 37 may be omitted, and a structure may be adopted in which a braze is placed around the portion to be brazed to the tube 33 and the fin 34.
  • the tube 33 and the fin 34 may be brazed and joined by melting the setter by heating at the time of brazing and distributing the molten solder to the boundary portion between the tube 33 and the fin 34.
  • the fins 34 may be formed of a brazing sheet having a two-layer structure including a core layer and a brazing material layer, and the tube 33 may be configured without the brazing material layer 37.
  • the above-mentioned boehmite layer can be provided on both sides of the core material layer.
  • the fins 34 are formed of a brazing sheet having a three-layer structure (a core layer + a three-layer structure including a brazing material layer on both sides provided with a boehmite layer) in which a brazing material layer provided with a boehmite layer on both surfaces of the core material layer You can also
  • the core material is, by mass%, Mn: 0.5 to 2.0%, Si: 1.3% or less, Fe: 0.25% or less, Cu: 1.3%
  • Zn 4.0% or less and made of an aluminum alloy having a composition of balance Al and unavoidable impurities
  • the brazing material layer contains 5.0 to 13.0% by mass%, balance Al and A combination of an aluminum alloy having a composition of unavoidable impurities can be exemplified.
  • a tube aluminum alloy containing 0.3 to 0.5% by mass of Si, 0.2 to 0.4% by mass of Mn and the balance of unavoidable impurities and Al is melted, and the cross-sectional shape of this alloy is obtained. (Thickness 0.26 mm ⁇ width 17.0 mm ⁇ total thickness 1.5 mm), and was used as a flat tube for a heat exchanger aluminum alloy. Furthermore, a brazing material layer was formed on the surface (upper surface), the back surface (lower surface), and the second side surface of the tube.
  • the brazing material layer comprises 3 g of Si powder (D (99) particle size 10 ⁇ m), 6 g of Zn-containing flux (KZnF 3 powder: D (50) particle size 2.0 ⁇ m), 1 g of an acrylic resin binder, and 3- A solution consisting of a mixture of methoxy-3-methyl-1 butanol and 16 g of isopropyl alcohol was roll coated and dried.
  • a boehmite film is formed on a fin as a precoat film, and this fin is used to form a minicore test body of a heat exchanger, and brazing is performed using a brazing film. It has been found that it is possible to manufacture a heat exchanger which is excellent in hydrophilicity and excellent in brazeability without causing discoloration of the fin surface.
  • the contact angle value after the dry and dry cyclic test showed a range of 10 to 30 °.
  • the mini-core test piece of the example has excellent hydrophilicity which can maintain the contact angle on the surface of the fin at a low value even under a severe test environment in which 16 cycles of drying for 16 hours are performed after immersion in running water for 14 hours.
  • the brazing of aluminum is characterized in that the oxide film present on the aluminum surface during brazing heat treatment is weakened by the effect of the flux, and the brazing material that has melted the surface flows together to join a large number of places.
  • the comparative example No. 14 is an example in which an acrylic resin is used as a precoat film in place of the boehmite film
  • the comparative example of No. 15 is an example of using a polyvinyl alcohol as a precoat film in place of the boehmite film
  • No. 5 The comparative example of 16 is an example which was changed to the boehmite film and made carboxymethylcellulose the precoat film.
  • the comparative example of No. 17 was changed into the boehmite film
  • the comparative example of 18 is an example which was changed to the boehmite film and made lithium silicate the precoat film. Since these silicate films are materials that are more resistant to heating than the films of the above-mentioned resins, although the hydrophilicity after brazing is excellent, the film surface is discolored, so the color change is large, and the appearance as fins after brazing It resulted in the above problems.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Geometry (AREA)
  • Combustion & Propulsion (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Abstract

La présente invention concerne une ailette en aluminium brasée à un tube en aluminium et munie intérieurement d'un circuit d'écoulement d'agent de refroidissement ; ladite ailette en aluminium étant caractérisée en ce que sa surface avant et/ou sa surface arrière sont munies d'un film de revêtement hydrophile composé d'un film de revêtement en boehmite présentant une épaisseur comprise entre 100 et 10 000 Å.
PCT/JP2018/042108 2017-11-24 2018-11-14 Ailette en aluminium à excellent caractère hydrophile après brasage, et échangeur de chaleur et son procédé de production WO2019102915A1 (fr)

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JP2002139282A (ja) * 2000-10-31 2002-05-17 Mitsubishi Electric Corp 熱交換器、冷凍空調装置、熱交換器の製造方法
JP2004042482A (ja) * 2002-07-12 2004-02-12 Mitsubishi Alum Co Ltd 熱交換器用アルミニウム材料およびそれを用いた熱交換器
JP2004330233A (ja) * 2003-05-06 2004-11-25 Mitsubishi Alum Co Ltd 熱交換器用チューブ
JP2006176855A (ja) * 2004-12-24 2006-07-06 Mitsubishi Paper Mills Ltd 熱交換器用アルミニウムフィン材の製造方法
JP2012237476A (ja) * 2011-05-10 2012-12-06 Nippon Light Metal Co Ltd 熱交換器用プレコートフィン材及び熱交換器
JP2012237477A (ja) * 2011-05-10 2012-12-06 Nippon Light Metal Co Ltd アルミニウム又はアルミニウム合金からなる熱交換器
JP2013137153A (ja) * 2011-12-28 2013-07-11 Mitsubishi Alum Co Ltd プレコートフィン材を使用したオールアルミニウム熱交換器
JP2014014740A (ja) * 2012-07-06 2014-01-30 Sharp Corp 表面処理装置
JP2016099100A (ja) * 2014-11-26 2016-05-30 三菱アルミニウム株式会社 熱交換器、及び熱交換器の製造方法
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JPS54163362U (fr) * 1978-05-08 1979-11-15
JPS59100271A (ja) * 1982-11-27 1984-06-09 Mitsubishi Alum Co Ltd 熱交換器用フィンの製造方法
JP2002139282A (ja) * 2000-10-31 2002-05-17 Mitsubishi Electric Corp 熱交換器、冷凍空調装置、熱交換器の製造方法
JP2004042482A (ja) * 2002-07-12 2004-02-12 Mitsubishi Alum Co Ltd 熱交換器用アルミニウム材料およびそれを用いた熱交換器
JP2004330233A (ja) * 2003-05-06 2004-11-25 Mitsubishi Alum Co Ltd 熱交換器用チューブ
JP2006176855A (ja) * 2004-12-24 2006-07-06 Mitsubishi Paper Mills Ltd 熱交換器用アルミニウムフィン材の製造方法
JP2012237476A (ja) * 2011-05-10 2012-12-06 Nippon Light Metal Co Ltd 熱交換器用プレコートフィン材及び熱交換器
JP2012237477A (ja) * 2011-05-10 2012-12-06 Nippon Light Metal Co Ltd アルミニウム又はアルミニウム合金からなる熱交換器
JP2013137153A (ja) * 2011-12-28 2013-07-11 Mitsubishi Alum Co Ltd プレコートフィン材を使用したオールアルミニウム熱交換器
JP2014014740A (ja) * 2012-07-06 2014-01-30 Sharp Corp 表面処理装置
JP2016099100A (ja) * 2014-11-26 2016-05-30 三菱アルミニウム株式会社 熱交換器、及び熱交換器の製造方法
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