WO2019081690A1 - Procédé de brasage amélioré et pièces revêtues de flux - Google Patents

Procédé de brasage amélioré et pièces revêtues de flux

Info

Publication number
WO2019081690A1
WO2019081690A1 PCT/EP2018/079366 EP2018079366W WO2019081690A1 WO 2019081690 A1 WO2019081690 A1 WO 2019081690A1 EP 2018079366 W EP2018079366 W EP 2018079366W WO 2019081690 A1 WO2019081690 A1 WO 2019081690A1
Authority
WO
WIPO (PCT)
Prior art keywords
flux
parts
equal
aluminum
anyone
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/EP2018/079366
Other languages
English (en)
Inventor
Ulrich Seseke-Koyro
Andreas Becker
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Solvay SA
Original Assignee
Solvay SA
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
Application filed by Solvay SA filed Critical Solvay SA
Publication of WO2019081690A1 publication Critical patent/WO2019081690A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • 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°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 of 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
    • B23K1/00—Soldering, e.g. brazing, or unsoldering
    • B23K1/008—Soldering within a furnace
    • 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
    • B23K1/012—Soldering with the use of hot gas
    • 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
    • B23K1/20—Preliminary treatment of work or areas to be soldered, e.g. in respect of a galvanic coating
    • B23K1/203—Fluxing, i.e. applying flux onto surfaces
    • 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
    • B23K35/36—Selection of non-metallic compositions, e.g. coatings or fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
    • B23K35/3601—Selection of non-metallic compositions, e.g. coatings or fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest with inorganic compounds as principal constituents
    • 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
    • B23K35/36—Selection of non-metallic compositions, e.g. coatings or fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
    • B23K35/3601—Selection of non-metallic compositions, e.g. coatings or fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest with inorganic compounds as principal constituents
    • B23K35/361—Alumina or aluminates
    • 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
    • B23K35/36—Selection of non-metallic compositions, e.g. coatings or fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
    • B23K35/362—Selection of compositions of fluxes
    • 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
    • B23K35/36—Selection of non-metallic compositions, e.g. coatings or fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
    • B23K35/365—Selection of non-metallic compositions of coating materials either alone or conjoint with selection of soldering or welding materials
    • 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
    • B23K2101/00—Articles made by soldering, welding or cutting
    • B23K2101/04—Tubular or hollow articles
    • B23K2101/14—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
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/08—Non-ferrous metals or alloys
    • B23K2103/10—Aluminium or alloys thereof

Definitions

  • the invention concerns a process for brazing parts of aluminum or aluminum alloys and parts of aluminum or aluminum alloy, partially or completely coated with a flux coating based on fluoroaluminate flux, wherein the flux load on the coated areas of the parts is equal to or greater than 1 g/m 2 and equal to or lower than 4.5 g/m 2 , relative to the dry weight of the flux.
  • Brazing of aluminum parts can be performed utilizing fluxes based on alkali metal fluoroaluminates. Fluxes of this type are generally considered to be noncorrosive. See for example, US patent 3,971,501 which applies a flux based on KA1F 4 and K 3 A1F 6 .
  • Aluminum alloys e.g. Al alloys with minor amounts of Mg
  • fluxes containing KA1F 4 , KA1F 4 and K 2 A1F 5 and/or K 2 A1F 5 H 2 0, optionally containing cesium fluoroaluminate, are used for brazing.
  • US patent application publication 2017/0036286 describes applying a flux which comprises KAIF 4 or CSAIF 4 or both as major constituent.
  • US patent application publication 2017/0072515 discloses a flux which is high in KA1F 4 and low in K 3 A1F 6 .
  • WO 2015/158767 discloses a flux which comprises KAIF 4 or CSAIF 4 or both as major constituent and certain metal salt additives, e.g. Li 3 AlF 6 , CaF 2 , CaC0 3 , MgF 2 , MgC0 3 , SrF 2 , SrC0 3 , BaF 2 , and BaC0 3 .
  • WO 2011/098120 discloses the addition of Li salts, e.g.
  • the flux can be applied in dry form, e.g. by kinetic spraying onto metal substrates as disclosed in US patent 6,949,300, or in a wet form, mostly suspended in water or an organic liquid, optionally together with additives such as binders, thickeners, suspension stabilizers, antifoaming agents, surfactants and thixotropic agents.
  • additives such as binders, thickeners, suspension stabilizers, antifoaming agents, surfactants and thixotropic agents.
  • solder metal or solder metal alloy or a precursor thereof e.g. zinc, silicon, germanium, copper, aluminum-silicon alloy.
  • a precursor of potassium fluoroaluminate may be used, e.g. K 2 SiF 6 , a potassium fluorozudie, or a potassium
  • the present invention solves this problem by providing the process of the present invention and by providing aluminum parts coated in a novel manner.
  • the invention in one aspect, provides a process for brazing of parts of aluminum or aluminum alloys wherein one or more parts to be brazed are fully or partially coated with a flux coating comprising at least one fluoroaluminate flux, wherein the parts fully or partially coated with a flux coating comprising at least one fluoroaluminate flux are assembled and brazed, with the proviso that the flux load on the coated areas of the parts is equal to or greater than 1 g/m2 and equal to or lower than 4.5 g/m2, relative to the dry weight of the flux in relation to the surface area of the coated part of the part.
  • the flux load is equal to or greater than 1 g/m 2 and equal to or lower than 4g/m 2 .
  • the invention concerns a part or parts of aluminum or aluminum alloy, partially or completely coated with a flux coating comprising at least one fluoroaluminate flux, with the proviso that the flux load on the coated areas of the parts is equal to or greater than 1 g/m 2 and equal to or lower than 4.5 g/m 2 , relative to the dry weight of the flux in relation to the surface area of the coated part of the part.
  • the flux load is equal to or greater than 1 g/m 2 and equal to or lower than 4g/m 2 .
  • the flux load on the coated areas of the parts is equal to or greater than 1 g/m 2 and equal to or lower than 4.5 g/m 2 , relative to the dry weight of the flux in relation to the surface area of the coated part of the part.
  • the flux load can be equal to or higher than 1 g/m 2 , equal to or higher than 1.5 g/m 2 or equal to or higher than 2 g/m 2 . In some aspects, loads of equal to or higher than 3 g/m 2 can be advantageous.
  • the flux load can be equal to or lower than 4.5 g/m 2 , equal to or lower than 4.0 g/m 2 or equal to or lower than 3.5 g/m 2 . In some aspects, loads of equal to or lower than 3 g/m 2 can be advantageous. Loads of equal to or higher than 1 g/m 2 and equal to or lower than 4g/m 2 can be preferred.
  • the at least one fluoroaluminate flux is selected from the group consisting of potassium fluoroaluminate fluxes, potassium fluoroaluminate and cesium fluoroaluminate fluxes, potassium fluoroaluminate and potassium fluorozudie fluxes, potassium fluoroaluminate and Si and optionally cesium fluoroaluminate containing fluxes, and potassium fluoroaluminate and potassium hexafluorosilicate containing fluxes.
  • Cesium fluoroaluminates are often selected from the group consisting of CsAlF 4 , CS 2 AIF 5 , CS 3 AIF 6 or mixtures of two or three thereof.
  • the presence of one or more cesium fluoroaluminates in a flux can improve the brazing properties, such as melting range of the flux, and/or the ability of the flux to enable brazing of aluminum parts or aluminum alloy parts comprising magnesium.
  • the content of K 3 AIF 6 in the fluoroaluminate flux is low.
  • the content of K 3 AIF 6 in the flux load is equal to or lower than 5%, preferably equal to or lower than 1% by weight.
  • these terms include the instances in which K 3 AIF 6 in the fluoroaluminate flux is absent, i.e. 0% by weight.
  • the flux comprises KA1F 4 .
  • the fluoroaluminate flux comprises KA1F 4 and at least one other flux selected from the group consisting of cesium
  • the fluoroaluminate flux comprises KA1F 4 in an amount equal to or more than 50% by weight, relative to the dry weight of the flux load.
  • the flux comprises more than 80% by weight of KA1F 4 , relative to the dry weight of the flux load. Very good brazing results are achieved with the most preferred flux if the flux comprises equal to or more than 85% by weight of KA1F 4 , and even equal to or more than 95% by weight of KA1F 4 .
  • the fluoroaluminate flux consists of KAIF 4 , i.e. the loaded flux consists of KAIF 4 .
  • the term "consists of KAIF 4" intends to relate to KAIF 4 including impurities in trace amounts of up to 1% by weight, preferably up to 0.5 % by weight, relative to the dry weight of the flux load.
  • the fluoroaluminate flux comprises KAIF 4 in an amount of less than 100% by weight relative to the dry weight of the flux load, the balance to 100% by weight relative to the dry weight of the flux load being at least one other flux selected from the group consisting of potassium
  • the flux load in the coating comprises equal to or more than 85 % by weight, and even equal to or more than 95% by weight of KAIF 4 relative to the dry weight of the flux load, the balance to 100% by weight, relative to the dry weight of the flux load, being at least one other flux selected from the group consisting of potassium fluoroaluminate, cesium fluoroaluminate, potassium fluorozudie, potassium fluorostannate and potassium hexafluorosilicate, wherein cesium fluoroaluminates are preferred.
  • cesium fluoroaluminates are present in the flux, generally at least one cesium
  • fluoroaluminate selected from the group consisting of CsAlF 4 , CS 2 AIF 5 and CS 3 AIF 6 , this often is added in an amount of 0.5 to 5 % by weight relative to the dry weight of the flux load.
  • Particularly preferred fluxes are fluxes consisting of from 85% to 99.5% by weight of KA1F 4 , and 0.5 to 15% by weight of at least one cesium fluoroaluminate selected from the group consisting of CsAlF 4 , CS 2 AIF 5 and CS 3 AIF 6 or mixtures of two or three of the foregoing.
  • the flux coating can, in one aspect, comprise at least one compound selected from the group consisting of LiF and Li 3 AlF 6 . Such compounds can enhance the corrosion resistance of brazed parts.
  • the flux coating consists of the flux load. Preferred aspects of the constituents of flux load are given above.
  • composition or "flux composition” are used.
  • the term “fiux load” refers to the dry weight of the flux consisting of fluxing active components on the coated areas of the coated parts. If nothing but flux is contained in the coating, then “fiux load” and “coating” are identical.
  • the coating may further comprise additives. For simplification, the additives are calculated by reference to the flux set at 100%) by weight, relative to the dry weight of the flux load. Thus, if it is stated that 20% by weight of silicon is added, then the coating contains 16.67% by weight of silicon, and the balance to 100% by weight of the coating is constituted by the flux load. This takes into consideration that either, a mixture of flux and additive may be applied to the parts, or that additives and flux may be applied sequentially to the parts.
  • the content of cesium in the mixture composed of fluoroaluminate flux, in particular the monopotassium fluoroaluminate is given is weight % of the Cs present in the flux mixture.
  • a content of 10 % by weight of cesium corresponds to a content of 17.75 % by weight of CsAlF 4 in the mixture.
  • the weight% content of Cs is then 10%.
  • composition or “flux composition” generally refers to a composition comprising the flux and at least a solvent.
  • composition or “flux composition” refer to a mixture of flux, solvent and optionally other additives before they are applied to form a coating.
  • any percentages are referred to the total composition set to 100% by weight.
  • the coating comprises the flux load and at least one additive.
  • additives are known. Additives improve or simplify the brazing process, they modify the way of the application of the flux, or they modify the properties of the brazed parts, e.g. the properties of the brazed parts in view of corrosion stability after brazing and during storage or use of the brazed parts.
  • Additives of this kind can be selected from the group consisting of solder metal (also denoted as filler metal), e.g. zinc, mixtures of silicon and aluminum, solder metal alloy, especially alloys based on aluminum and silicon, optionally also containing zinc or other metals, solder metal alloy precursors, e.g. silicon, germanium or copper as described in US patent 5, 100,0486.
  • Solder metal from Al-Si alloy or Si as solder metal precursor are especially preferred. Flux coatings comprising such additives allow the brazing of uncladded aluminum parts or aluminum alloy parts.
  • the solder metal or solder metal precursors, if present in the flux load, are added preferably in an amount of 2 to 30 % by weight relative to the dry flux load set as 100% by weight.
  • the coating comprises at least one compound selected from the group consisting of LiF and L1 3 AIF 6 .
  • LiF and/or L1 3 AIF 6 are preferably present in an amount which corresponds to 80 per mol to 120 % per mol of K 2 AIF 5 or its hydrate or a precursor forming it (e.g. potassium fluorozudie) during brazing in the coating.
  • Metal salts of metals of the main group or sub groups of the periodic system of the elements for example, halides, nitrates, carbonates or oxides of zirconium, niobium, lanthanum, yttrium, cerium, titanium, strontium, indium, tin, antimony, or bismuth as described in US patent application publication No. 2007-0277908 can be added to improve the surface properties of the brazed parts. These additives can be added preferably in an amount of equal to or less than 3 % by weight of the total dry weight of the flux load (set as 100% by weight).
  • additives modify the way of application of the flux and are especially suitable to allow wet applications, such as spraying or painting.
  • Preferred additives are solvents, binders, thickeners, suspension stabilizers, antifoaming agents, surfactants and thixotropic agents.
  • solvent includes the expression “suspension agent”.
  • Preferred solvents are deionized water, mono-, di- or tribasic aliphatic alcohols, especially those with 1 to 4 carbon atoms, e.g. methanol, ethanol, isopropanol, or ethylene glycol, or glycol alkyl ethers, wherein alkyl preferably denotes linear or branched aliphatic CI to C4 alkyl.
  • Non-limiting examples are glycol monoalkyl ethers, e.g. 2-methoxy ethanol or diethylene glycol, or glycol dialkylethers, for example, dimethyl glycol (dimethoxy ethane). Mixtures comprising two or more of the liquids are also suited very well. Isopropanol or mixtures containing isopropanol are especially suitable as solvent.
  • Binders improve, for example, the adhesion of the flux mixture after their application on the parts to be brazed.
  • Suitable binders can be selected for example from the group consisting of organic polymers. Such polymers are physically drying (i.e., they form a solid coating after the liquid is removed), or they are chemically drying (they may form a solid coating e.g. under the influence of chemicals, e.g. oxygen or light which causes a cross linking of the molecules), or both.
  • Suitable polymers include polyolefmes, e.g. butyl rubbers, polyurethanes, resins, phthalates, polyacrylates, polymethacrylates, vinyl resins, epoxy resins, nitrocellulose, polyvinyl acetates or polyvinyl alcohols.
  • Flux compositions containing water as liquid and water-soluble polymers, for example, polyurethane, or polyvinyl alcohol as binder are especially suitable because they have the advantage that, during the brazing process, water is evaporated instead of possibly flammable organic liquids.
  • Other additives are, for example, suspension stabilizers, surfactants, especially nonionic surfactants, e.g. Antarox BL 225, a mixture of linear C8 to CIO ethoxylated and propoxylated alcohols, thickeners, e.g. methyl butyl ether, thixotropic agents, e.g. gelatine or pectines, or a wax as described in EP-A 1808264.
  • Percentages here relate to the total weight of the compositions including flux and, if present, at least one component selected from binders, solvents, thickeners, suspension stabilizers, antifoaming agents, surfactants and thixotropic agents.
  • the total content of the flux, and if present, brazing additives, e.g. solder metal, solder metal alloy, solder precursor, and metal salts, improving the brazing or surfaces properties, e.g. cesium compounds, Li compounds, alkaline earth metal salts, rare metal salts, in the total composition generally is equal to or greater than 1 % by weight, more preferably equal to or greater than 5 % by weight, especially preferably, equal to or greater than 10 % by weight of the total flux composition.
  • the total content of the flux, and if present, brazing additives in the composition is equal to or lower than 70 % by weight. Preferably, it is equal to or lower than 50 % by weight.
  • the binder if present, is preferably equal to or greater than 1 % by weight of the total flux composition.
  • the binder if present, is generally contained in an amount equal to or lower than 30 % by weight, preferably equal to or lower than 25 % by weight of the total composition.
  • the thixotropic agent if present, is preferably contained in an amount of equal to or greater than 1 % by weight of the total flux composition. Generally, if present, it is contained in an amount equal to or lower than 20 % by weight, preferably equal to or lower than 10 % by weight.
  • the thickener if present, is preferably contained in an amount of equal to or greater than 1 % by weight, more preferably equal to or greater than 5 % by weight of the total flux composition.
  • thickener if present, is contained in an amount equal to or lower than 15 % by weight, more preferably equal to or lower than 10 % by weight of the total composition.
  • each of suspension stabilizers, antifoaming agents or surfactants, if present is preferably equal to or lower than 2 % by weight of the composition.
  • the solvent is the balance to 100% by weight.
  • wet coatings especially those comprising a solvent
  • the flux load such that after drying, the specific flux load is obtained.
  • the formation of fully or partially coated parts of aluminum or aluminum alloys can be performed according to well-known manners.
  • a dry method can be used, e.g. by applying electrostatic power and/or plasma.
  • the fully or partially coated parts of aluminum or aluminum alloys can also be produced according to wet methods.
  • the flux is dispersed a solvent forming a composition; other additives may be suspended, or are dissolved according to their solubility.
  • Such compositions can be applied by painting, printing or spraying onto the parts to be coated, or the parts can be immersed into the suspension with subsequent drying to remove the solvent. Drying can be performed immediately before brazing, or, if desired, beforehand to provide coated parts for the shelf, intended for later brazing.
  • Polyvinyl alcohol is very suitable as water-soluble package for the flux as described in US patent application publication 2006/0231162. Such packages can be handled without dust formation, and after addition of water, they form a suspension in water including a flux and the water soluble polymer as binder.
  • the coating may be formed sequentially.
  • solder metal, a solder metal alloy or a solder metal alloy precursor can be applied to the parts separately from the flux coating, e.g. by plating the parts with solder metal, solder metal alloy or solder metal precursor before formation of the coating.
  • the flux load after drying (if drying is necessary) must be in the specific range of the invention.
  • the parts are assembled with fully or partially coated parts of aluminum or aluminum alloys according to the present invention and/or other metal parts, in particular parts of aluminum or aluminum alloys, and brazed.
  • the fully or partially coated parts of aluminum or aluminum alloys and optionally other parts to be joined by brazing are assembled (before or after drying if coated according to a wet process) and usually heated to about 560°C to about 610°C. This can be done in an inert gas atmosphere, e.g. in a nitrogen or argon atmosphere.
  • the brazed parts can be subjected to a heat treatment after brazing.
  • the process according to the present invention allows for brazing of parts with an exceptionally low loading of flux. It was surprisingly found that satisfactory to good brazing results can be achieved by this process.
  • the reduction to such low loads leads to a higher economic value of the process, less waste, less cleaning of brazed parts, less formation of by-products such as post braze residues.
  • the corrosion resistance of parts can benefit from lower flux loads. Interactions of post braze residues with liquids, such as cooling liquids in heat exchangers, can lead to formation of solids, and thus may impact the lifetime and efficiency of heat exchanger devices and other equipment comprising brazed parts. Reduction of flux load can lead to the reduction of the impact of post braze residue due to reduced formation of solids.
  • the preferred fluxes according to the present invention in particularly fluxes with a high content of KAIF 4 , for example equal to or more than 85% by weight of KAIF 4 , display a particularly high activity during the brazing process which accounts for the possibility of using a flux load as defined in the present specification.
  • the invention further concerns the a process or parts of aluminum of aluminum alloy, wherein a solder metal alloy is applied to the aluminum or aluminum alloy parts to be brazed, and wherein the metal alloy is an alloy comprising or consisting of Al and Si.
  • the solder metal alloy or a solder metal alloy precursor can be applied in addition to the flux coating.
  • the invention further concerns brazed parts obtained by the process according to the present invention, or obtained by brazing the parts according to the present invention.
  • KAIF 4 was dry-mixed in a turbular mixer with CsAlF 4 or a
  • CS 2 AIF 5 /CSAIF 4 15:85 blend The mixtures contained 5, 10 and 15 % Cs (as CsAlF 4 or Cs 2 AlF 5 /CsAlF 4 blend).
  • the flux composition was applied as a dry powder "pile" in the center of a 50 x 50 mm coupon of Al 1050 with flux loads of 1 or 2 mg on the coupon.
  • the coupons were subjected to a CAB heating cycle with a heating rate of 30°C per minute up the peak temperature of 600°C and stopped, followed by cooling down to room temperature. After completion of the heating cycle, the coupons were inspected visually, and the solidified flux residue (circle type) was determined in mm 2 as given in the illustration 1. For each flux and loading, the experiment was repeated three times, one sample was done only once. The average of each set of three experiments is listed in the following table Table 2: Determination of spreading behavior
  • Example 2 Brazing experiments Aluminum parts in the form of a 25x25 mm coupons Al 3003 (0.4 mm thickness, with 10 % 4343 AlSi clad alloy ) were coated with a flux sample, the flux sample was mixed with a few drops of isopropanol to create a uniform flux layer on the coupon.
  • a stainless steel wire of 0,33 mm in diameter was place on the coupon and on to it an aluminum (Al 1050) angle (overall length of 40 mm) was positioned such that the end of the angle with its two legs lay on the wire. By this, the angle's legs were not in contact with the coupon, whereas the tip of the V-shape of the angle was in contact with the coupon.
  • the Brazing Setup is depicted in illustration 2.
  • the distance between the end of the legs to the wire was 1 mm.
  • This setup created an interspace between angle and coupon, which enhanced the possibility to judge the formation of joints in the brazing procedure, as the interspace fills with filler in the brazing process when brazing is successive.
  • the specimen was then brazed a laboratory furnace under CAB conditions with a heating rate of 30°C/ minutes up to 605 °C, with a holding time at peak temperature of
  • the flux of example 1.3 gave a 10% better brazing result than the flux of example 1.1.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Nonmetallic Welding Materials (AREA)

Abstract

L'invention concerne des pièces en aluminium, par exemple des pièces nécessaires pour des échangeurs de chaleur, qui sont brasées à l'aide d'une charge de faible flux, la charge de flux sur les zones revêtues des pièces étant supérieure ou égale à 1 g/m2 et inférieure ou égale à 4,5 g/m2. Les flux préférés comprennent une quantité substantielle de KAIF4. Un autre aspect de l'invention concerne des pièces revêtues d'une telle charge de faible flux.
PCT/EP2018/079366 2017-10-27 2018-10-26 Procédé de brasage amélioré et pièces revêtues de flux Ceased WO2019081690A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
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WO2025261048A1 (fr) * 2024-06-18 2025-12-26 广州汉源微电子封装材料有限公司 Flux, et son procédé de préparation ainsi que son utilisation

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US4689092A (en) 1985-01-11 1987-08-25 Kabushiki Kaisha Toyota Chuo Kenkyusho Brazing flux
US5100486A (en) 1989-04-14 1992-03-31 The United States Of America As Represented By The United States Department Of Energy Method of coating metal surfaces to form protective metal coating thereon
EP0936024A1 (fr) * 1997-05-06 1999-08-18 Showa Aluminum Corporation Composition de fondant servant au brasage d'un materiau d'aluminium et procede de brasage d'un materiau d'aluminium
EP1187699A1 (fr) * 1999-04-22 2002-03-20 Corus Aluminium Walzprodukte GmbH Materiau composite en feuille pour brasage
WO2003089176A2 (fr) * 2002-04-22 2003-10-30 Alcoa Inc. Feuille de brasage enrobee
US6949300B2 (en) 2001-08-15 2005-09-27 Delphi Technologies, Inc. Product and method of brazing using kinetic sprayed coatings
US20060231162A1 (en) 2003-12-17 2006-10-19 Solvay Fluor-Gmbh Fluxing agent
EP1808264A1 (fr) 2006-01-11 2007-07-18 Akzo Nobel Coatings International B.V. Composition de flux de soudure comportant un lubrifiant
WO2007080160A1 (fr) * 2006-01-11 2007-07-19 Akzo Nobel Coatings International B.V. Composition de fondant pour brasage comprenant un lubrifiant
US20070277908A1 (en) 2004-03-20 2007-12-06 Solvay Fluor Gmbh Non-Corrosive Auxiliary Agents For Soldering Aluminium
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EP2070638A1 (fr) * 2007-12-11 2009-06-17 Solvay Fluor GmbH Procédé pour le brasage de pièces en titane et en aluminium et pièces pouvant être obtenus par ce procédé
WO2009127707A1 (fr) * 2008-04-18 2009-10-22 Solvay Fluor Gmbh Procédé anticorrosion pour pièces en aluminium brasées au fluoroaluminate
WO2011098120A1 (fr) 2010-02-10 2011-08-18 Solvay Fluor Gmbh Flux formant un résidu de brasage insoluble
WO2015158767A2 (fr) 2014-04-16 2015-10-22 Solvay Sa Procédé de brasage d'alliages d'aluminium et flux
US20170072515A1 (en) 2014-03-11 2017-03-16 Solvay Sa Flux for brazing
EP3231545A1 (fr) * 2014-12-11 2017-10-18 UACJ Corporation Procédé de brasage

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3971501A (en) 1975-04-09 1976-07-27 Alcan Research And Development Limited Method of brazing aluminum
US4689092A (en) 1985-01-11 1987-08-25 Kabushiki Kaisha Toyota Chuo Kenkyusho Brazing flux
US5100486A (en) 1989-04-14 1992-03-31 The United States Of America As Represented By The United States Department Of Energy Method of coating metal surfaces to form protective metal coating thereon
EP0936024A1 (fr) * 1997-05-06 1999-08-18 Showa Aluminum Corporation Composition de fondant servant au brasage d'un materiau d'aluminium et procede de brasage d'un materiau d'aluminium
EP1187699A1 (fr) * 1999-04-22 2002-03-20 Corus Aluminium Walzprodukte GmbH Materiau composite en feuille pour brasage
US6949300B2 (en) 2001-08-15 2005-09-27 Delphi Technologies, Inc. Product and method of brazing using kinetic sprayed coatings
WO2003089176A2 (fr) * 2002-04-22 2003-10-30 Alcoa Inc. Feuille de brasage enrobee
US20060231162A1 (en) 2003-12-17 2006-10-19 Solvay Fluor-Gmbh Fluxing agent
US20070277908A1 (en) 2004-03-20 2007-12-06 Solvay Fluor Gmbh Non-Corrosive Auxiliary Agents For Soldering Aluminium
EP1808264A1 (fr) 2006-01-11 2007-07-18 Akzo Nobel Coatings International B.V. Composition de flux de soudure comportant un lubrifiant
WO2007080160A1 (fr) * 2006-01-11 2007-07-19 Akzo Nobel Coatings International B.V. Composition de fondant pour brasage comprenant un lubrifiant
DE102008009695A1 (de) * 2007-03-02 2008-09-04 Behr Gmbh & Co. Kg Halbzeug, insbesondere extrudiertes Profilrohr
EP2070638A1 (fr) * 2007-12-11 2009-06-17 Solvay Fluor GmbH Procédé pour le brasage de pièces en titane et en aluminium et pièces pouvant être obtenus par ce procédé
WO2009127707A1 (fr) * 2008-04-18 2009-10-22 Solvay Fluor Gmbh Procédé anticorrosion pour pièces en aluminium brasées au fluoroaluminate
WO2011098120A1 (fr) 2010-02-10 2011-08-18 Solvay Fluor Gmbh Flux formant un résidu de brasage insoluble
US20170072515A1 (en) 2014-03-11 2017-03-16 Solvay Sa Flux for brazing
WO2015158767A2 (fr) 2014-04-16 2015-10-22 Solvay Sa Procédé de brasage d'alliages d'aluminium et flux
US20170036286A1 (en) 2014-04-16 2017-02-09 Solvay Sa Process for brazing of aluminum alloys and a flux
EP3231545A1 (fr) * 2014-12-11 2017-10-18 UACJ Corporation Procédé de brasage

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2025261048A1 (fr) * 2024-06-18 2025-12-26 广州汉源微电子封装材料有限公司 Flux, et son procédé de préparation ainsi que son utilisation

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