CN110290882B - Aluminum extruded flat multi-hole tube having excellent brazeability and method for manufacturing the same - Google Patents

Aluminum extruded flat multi-hole tube having excellent brazeability and method for manufacturing the same Download PDF

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Publication number
CN110290882B
CN110290882B CN201880011508.8A CN201880011508A CN110290882B CN 110290882 B CN110290882 B CN 110290882B CN 201880011508 A CN201880011508 A CN 201880011508A CN 110290882 B CN110290882 B CN 110290882B
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aluminum
tube
brazing material
billet
mass
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CN110290882A (en
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中村真一
山下尚希
熊谷英敏
永尾诚一
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Uacj Corp Extrusion Processing
UACJ Corp
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Uacj Corp Extrusion Processing
UACJ Corp
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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
    • B23K1/0008—Soldering, e.g. brazing, or unsoldering specially adapted for particular articles or work
    • B23K1/0012—Brazing heat exchangers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00—Extruding metal; Impact extrusion
    • B21C23/22—Making metal-coated products; Making products from two or more metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C25/00—Profiling tools for metal extruding
    • B21C25/02—Dies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
    • B21C37/15—Making tubes of special shape; Making tube fittings
    • B21C37/151—Making tubes with multiple passages
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • F28F21/089—Coatings, claddings or bonding layers made from metals or metal alloys
    • 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
    • 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
    • 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
    • F28D1/0535—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 the conduits having a non-circular cross-section
    • F28D1/05366—Assemblies of conduits connected to common headers, e.g. core type radiators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F2255/00—Heat exchanger elements made of materials having special features or resulting from particular manufacturing processes
    • F28F2255/16—Heat exchanger elements made of materials having special features or resulting from particular manufacturing processes extruded

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Materials Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Metallurgy (AREA)
  • Geometry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Extrusion Of Metal (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Abstract

Provided is a method for manufacturing an aluminum extruded flat porous tube, wherein excellent outer surface brazeability is effectively improved simply and inexpensively, and the tube is advantageously manufactured. In the aluminum extruded flat porous tube 10 formed by simultaneous extrusion using the aluminum tube main body material and the brazing material formed of the Al — Si based aluminum alloy, the brazing material is exposed over the entire region of the tube outer peripheral wall portion or at least a part of the flat portion in the tube outer peripheral wall portion, thereby forming the brazing material portion 18.

Description

Aluminum extruded flat multi-hole tube having excellent brazeability and method for manufacturing the same
Technical Field
The present invention relates to an aluminum extruded flat multi-hole tube having excellent brazeability and a method for manufacturing the same, and more particularly, to an aluminum extruded flat multi-hole tube for a heat exchanger, which can be suitably used as a heat transfer tube of a heat exchanger (particularly, an automobile heat exchanger such as an automobile air conditioner) and has stable and uniform brazeability by stably and inexpensively providing a brazing material portion to an outer peripheral portion of the aluminum extruded flat multi-hole tube brazed to a fin, and a method for favorably manufacturing the same.
Background
Conventionally, an aluminum extruded flat perforated tube having a flat cross-sectional shape as a whole, which is obtained by extrusion processing of an aluminum material, is used as a refrigerant passage tube of an automotive heat exchanger, a refrigerant flows in the refrigerant passage tube, while an aluminum fin is attached and fixed by brazing in a direction perpendicular to the refrigerant passage tube to configure a heat exchanger, and then air as a heat exchange fluid flows along the fin to perform heat exchange between the refrigerant and the air. Conventionally, an aluminum fin formed of a brazing sheet coated with an Al — Si alloy brazing material is used, and the aluminum fin is joined by brazing to such an aluminum extruded flat multi-hole tube by flux brazing, or fluxless brazing such as vacuum brazing or atmosphere brazing.
However, in recent years, thinning of the aluminum fin material has been demanded from the viewpoint of weight reduction of the aluminum heat exchanger, and in this case, contrary to the conventional art, further thinning of the fin material can be expected if the fin material can be changed from a brazing sheet to a bare material (bare material) and the tube is coated with a brazing material. However, no method for stably and inexpensively coating an aluminum extruded flat multi-hole tube with a brazing material on an industrial scale is currently established.
For this reason, as a method for coating an aluminum extruded flat multi-hole tube with a brazing material, the following methods (Japanese patent application laid-open No. 6-504485 and Japanese patent application laid-open No. 7-308795) have been proposed: the aluminum extruded flat porous tube obtained by dipping the tube in a mixture of flux and silicon metal powder or coating the mixture on the tube, heating and drying the tube to form a state in which the mixture is coated on the outer surface of the tube, and combining the tube with a bare material and heating the tube in a brazing furnace to alloy the tube and form an Al — Si molten brazing flux (japanese: molten ろう) on the joint surface of the tube and the tube, thereby brazing the tube. However, these methods have problems that the coating and coating operation is troublesome, the cost is high, uniform coating is difficult, and adhesion of Si powder is likely to be insufficient, and uniform and stable brazing bonding is difficult. Further, a technique of thermally spraying brazing material on an aluminum extruded flat and porous tube has also been proposed (japanese patent application laid-open No. 2002-172485), but this technique also has a problem that it is difficult to achieve uniform coating, and it is necessary to introduce new equipment, etc., which increases the cost. In order to solve these problems, it is considered effective to use an extruded flat porous tube stably and uniformly covered with a brazing material on the outer surface.
On the other hand, as the extruded flat and porous tube, a tube obtained by extruding aluminum or an aluminum alloy through a branched hole is generally used, and a technique of covering a brazing material in the extrusion process of such an aluminum extruded flat and porous tube is proposed in japanese patent application laid-open No. 10-258356. However, the covered brazing material layer is entangled in both end portions of the aluminum extruded flat multi-hole tube, and there is a problem that entanglement failure of the brazing material layer is likely to occur. In order to solve this problem, jp-a-10-197175 also proposes to form projections on both side edges of the pipe, but since it is necessary to provide projections on both side edges of the aluminum extruded flat perforated pipe, there is a problem that versatility is extremely low due to restrictions on shape and the like.
Further, jp 63-97309 a proposes a method of manufacturing a clad pipe in which a brazing material layer is coated on an outer surface flat portion of a peripheral wall portion by simultaneously performing extrusion processing using a composite billet composed of an aluminum core material forming material and a skin material forming material (which is formed of an Al — Si-based aluminum brazing alloy material), but such a clad pipe has problems such as the following: when the positions of the port holes of the split dies and the composite billet are slightly displaced due to the influence of metal flow (metal flow) of the skin material forming material, the brazing material layer is entangled in the welded portion, and entanglement failure occurs.
Documents of the prior art
Patent document
Patent document 1: japanese Kohyo publication Hei 6-504485
Patent document 2: japanese laid-open patent publication No. 7-308795
Patent document 3: japanese laid-open patent publication No. 2002-
Patent document 4: japanese laid-open patent publication No. 10-258356
Patent document 5: japanese laid-open patent publication No. 10-197175
Patent document 6: japanese laid-open patent publication No. 63-97309
Disclosure of Invention
Problems to be solved by the invention
Under the above circumstances, the present inventors have conducted intensive studies in order to join another aluminum member such as an aluminum fin to the outer peripheral portion of an aluminum extruded flat multi-hole tube obtained by extrusion processing of an aluminum material and to stably and inexpensively provide an Al — Si based brazing material layer for forming a molten brazing agent to the outer surface of the multi-hole tube, and as a result, have found that an aluminum brazing material formed of an Al — Si based alloy can be favorably exposed to the outer peripheral portion of the tube of the obtained aluminum extruded flat multi-hole tube by using a general aluminum tube base material and an aluminum brazing material formed of an Al — Si based alloy as the extruded aluminum materials and simultaneously performing thermal extrusion processing of them, and further found that by providing a predetermined front plate in front of the extrusion direction of a composite billet (which is obtained by combining a thermally extruded aluminum tube base material and an aluminum brazing material formed of an Al — Si based alloy), the present inventors have found that the brazing material layer can be easily and inexpensively exposed to a uniform brazing material layer and can be formed without causing the entanglement failure, because the brazing material layer can be applied to all of the extruded flat and porous tubes which are generally used.
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an aluminum-extruded flat perforated tube having excellent outer surface brazeability, which is obtained by extrusion processing of an aluminum material and has a flat cross-sectional shape as a whole, simply and inexpensively, and to provide a method for advantageously producing the aluminum-extruded flat perforated tube that can exhibit such excellent characteristics.
Means for solving the problems
In order to solve the above-described problems, the present invention is an aluminum extruded flat porous tube having excellent brazeability, which is an extruded tube having a flat cross-sectional shape as a whole obtained by extrusion processing of an aluminum material, and having a plurality of flow passages extending independently in parallel to a tube axis direction and arranged in a longitudinal direction of the flat cross-sectional shape with an internal partition wall portion extending in the tube axis direction interposed therebetween,
the aluminum extruded flat porous tube is formed by extrusion processing using an aluminum tube main body material and an aluminum brazing material formed of an Al-Si based aluminum alloy as the aluminum material, wherein the aluminum brazing material is exposed over the entire region of a tube outer peripheral wall portion or at least a part of a flat portion in the tube outer peripheral wall portion to form a brazing material portion, and the brazing material portion is present at a ratio of 50% or more and 100% or less of a circumferential length of the tube outer peripheral wall portion in a tube cross section, while the brazing material portion located in the tube outer peripheral wall portion is present at a ratio of 90% or less of a thickness of the tube outer peripheral wall portion.
In a preferred embodiment of the aluminum extruded flat multi-hole tube having excellent brazeability of the present invention, as the aluminum brazing material, an aluminum alloy containing 1.0 to 13.0 mass% of Si, and further containing one or more of 1.4 mass% or less of Mn, 0.05 to 0.30 mass% of Cr, 0.05 to 0.30 mass% of Zr, 0.05 to 0.30 mass% of Ti, and 0.0001 to 0.1 mass% of Sr, with the balance being aluminum and unavoidable impurities is used; on the other hand, as the aluminum pipe main body material, an aluminum alloy containing 0.7 mass% or less of Cu and 1.4 mass% or less of Mn, further containing one or more of 0.05 to 0.30 mass% of Cr, 0.05 to 0.30 mass% of Zr, 0.05 to 0.30 mass% of Ti, and 0.0001 to 0.1 mass% of Sr, and the balance being aluminum and unavoidable impurities is used.
In addition, according to one preferable embodiment of the aluminum extruded flat porous tube having excellent brazeability of the present invention, as the aluminum material for the extrusion processing, a composite billet composed of the aluminum pipe main body material and the aluminum brazing material is used.
In another preferred aspect of the present invention, the composite billet has an integral core-sheath structure including a core billet made of the aluminum pipe body material and a sheath billet made of the aluminum brazing material and positioned around the core billet.
In addition, in one of advantageous aspects of the aluminum extruded flat perforated pipe having excellent brazeability of the present invention, the extruded pipe is formed by extrusion processing of the aluminum material using a split flow die.
In order to advantageously produce the aluminum extruded flat and porous tube of the present invention, the present invention also provides a method for producing an aluminum extruded flat and porous tube having excellent brazeability, characterized in that a composite billet made of an aluminum pipe body material and an aluminum brazing material (made of an Al — Si-based aluminum alloy) and a front plate made of the same material as the aluminum pipe body material are used, the front plate is configured such that the diameter of the front plate is 90% or more and 100% or less with respect to the diameter of the composite billet, the thickness of the front plate is 5% or more and 30% or less with respect to the diameter of the composite billet, the front plate is disposed on the front side in the extrusion direction of the composite billet, and the front plate and the composite billet are extruded together using a split die.
Further, in the method for producing an aluminum extruded flat multi-hole tube according to the present invention, it is preferable that the composite billet has an integral core-sheath structure including a core billet formed of the aluminum pipe body material and a sheath billet formed of the aluminum brazing material and positioned around the core billet.
The present invention is also directed to an aluminum heat exchanger, which includes the aluminum extruded flat and porous tube of the present invention and an aluminum external fin brazed to an outer surface of the aluminum extruded flat and porous tube.
ADVANTAGEOUS EFFECTS OF INVENTION
Thus, in the aluminum extruded flat multi-hole tube configured as the present invention, the brazing material layer made of the aluminum brazing material is present in the entire region of the outer peripheral portion of the tube or in part of at least the flat portion of the outer peripheral portion of the tube, and the brazing material layer is not involved in both end edge portions of the extruded flat multi-hole tube, and therefore, the tube can be advantageously used as a heat transfer tube of a heat exchanger (a radiator, a heater, or the like) having an effective brazing property on the outer surface side of the tube.
Further, the aluminum extruded flat and porous tube of the present invention is composed of the aluminum tube main body material and the aluminum brazing material, and is directly formed by simultaneous extrusion processing of these 2 materials, so that the characteristics of the tube can be ensured by the aluminum tube main body material, and the brazeability can be effectively exhibited by the aluminum brazing material, and thus, there is also an advantage that the degree of freedom in designing the intended extruded flat and porous tube can be favorably improved.
Further, according to the method for producing an aluminum extruded flat perforated pipe having excellent brazeability of the present invention, since the predetermined front plate is simultaneously extruded from the split dies in a state where the front plate is disposed in front of the composite billet composed of the aluminum pipe main body material and the aluminum brazing material (which is formed of an Al — Si-based aluminum alloy) in the extrusion direction, the entrainment of the aluminum brazing material into the aluminum pipe main body material can be effectively suppressed or prevented, and thereby the following aluminum extruded flat perforated pipe can be advantageously obtained: the obtained extruded flat multi-hole tube was free from the entanglement of the brazing material layer into both end edge portions thereof, and had stable quality in terms of brazeability.
Further, in the case of an aluminum heat exchanger constructed by using the aluminum extruded flat multi-hole tube of the present invention, assembling it with an aluminum outer fin (bare fin), and joining them by brazing heating, by using the extruded flat multi-hole tube exposed with the aluminum brazing material, brazing fixation of the aluminum outer fin can be advantageously achieved, and the objective heat exchanger can be obtained simply and inexpensively.
Drawings
Fig. 1 is a cross-sectional explanatory view schematically showing an example of the aluminum extruded flat multi-hole tube of the present invention, (a) shows the entire view, (b) shows a part of the widthwise central portion thereof enlarged, and (c) shows an explanatory view showing a part of the widthwise end portions of an example in which the brazing material portion has a different exposure ratio enlarged.
Fig. 2 is an explanatory view of a composite material used in the examples, wherein (a) and (b) are views showing a cross section and a longitudinal section thereof, respectively, and (c) is an explanatory view showing a longitudinal section of the composite material in a state where a front panel is provided.
Fig. 3 is an explanatory view of a single blank used in the example, and (a) and (b) are views showing a cross section and a longitudinal section thereof, respectively, and (c) is an explanatory view showing a longitudinal section of the single blank in a state where a front plate is provided.
Detailed Description
Hereinafter, in order to explain the present invention more specifically, representative embodiments of the present invention will be described in detail with reference to the drawings.
First, fig. 1 schematically shows an example of an aluminum extruded flat perforated pipe of the present invention in a cross-sectional view in a direction perpendicular to the longitudinal direction (pipe axis direction) thereof. Here, as shown in fig. 1(a), the flat multi-hole tube 10 of the present invention is an extruded tube of an aluminum material having a flat cross-sectional shape as a whole, and includes a plurality of rectangular flow paths 12 extending independently in parallel to the tube axis direction, and the plurality of flow paths 12 are arranged at predetermined intervals in the longitudinal direction (the left-right direction in the drawing) of the flat shape as the tube width direction. The opposing upper and lower surfaces of the flat multi-hole tube 10 are flat surfaces, and external fins (not shown) such as plate fins and corrugated fins are used as bare fins, and are attached to the upper and lower surfaces by brazing, and can be used as a heat exchanger. The cross-sectional shape of the flow channel 12 is here a rectangular shape, but various shapes such as a known circular shape, an elliptical shape, a triangular shape, or a combination thereof may be employed.
In the flat multi-hole tube 10 having such a structure of the present invention, as is apparent from fig. 1(a) to (c), the periphery of the flow path 12 including the inner partition wall 16 located between the adjacent flow paths 12, 12 is made of a normal aluminum tube main body material, and on the other hand, a layer of a brazing material 18 made of an aluminum brazing material is present in at least a part of the flat portion (which provides the flat surface) of the tube outer peripheral wall portion 14 over the entire circumference of the tube outer peripheral wall portion 14, and the brazing material 18 is exposed to the outer surface (here, the entire outer peripheral surface) of at least a part of the tube outer peripheral wall portion 14. Thus, the extruded flat multi-hole tube 10 exhibiting excellent brazeability can be obtained by disposing the brazing material portions 18 on the tube outer peripheral wall portion 14 and passing the brazing material component of the aluminum brazing material constituting the brazing material portions 18.
Further, as described above, the brazing material portion 18 is exposed on the outer surface side of the tube outer peripheral wall portion 14 of at least a part of the flat portion (flat surface) of the entire tube circumferential length L in the cross section of the flat multi-hole tube 10, and is preferably configured to be exposed in a range corresponding to 50% or more and 100% or less of the entire tube circumferential length L, and is favorably 60% or more, more favorably 70% or more. As a result, the brazing material of aluminum contributing to brazing is stably and uniformly exposed to the outer peripheral surface of the flat multi-hole tube 10 and the brazing material portions 18 are exposed to a predetermined region of the entire tube peripheral length L, and particularly, as shown in fig. 1(a), the most preferable state is a case where the brazing material portions 18 are present over the entire tube peripheral length L. If the exposed area is less than 50% of the circumferential length L of the tube outer peripheral wall portion 14, defects such as fin non-joining and fin peeling may occur during brazing heating. Note that the thickness of the exposed region of the brazing material part 18 does not need to be the same throughout the entire circumference L of the tube, and the brazing material part 18 may be exposed at different exposure ratios of the thicknesses, as shown in fig. 1(c), for example. Further, it is preferable that such brazing material portions 18 are continuously exposed over the entire circumference L of the tube, but any of the following cases may be used: exposed in a locally discontinuous state; or exposed to a predetermined length at a plurality of positions in the circumferential direction of the pipe so as to extend in the pipe axial direction.
In the flat multi-hole tube 10 having such a structure, as shown in fig. 1(a), the brazing material portion 18 is exposed over the entire circumference of the outer peripheral portion of the tube outer peripheral wall portion 14 or at least a part of the flat portion (here, over the entire circumference), and a normal aluminum tube main body material is present in the portion where the brazing material portion 18 is not exposed, that is, around the flow channel 12 including the inner partition wall portion 16 located between the adjacent flow channels 12, 12. Here, as shown in the drawing, the tube outer peripheral wall portion 14 constitutes the outer peripheral wall of the flat perforated tube 10 and functions as an outer partition wall portion of each flow channel 12. In the case where the brazing material portion 18 formed in the tube outer peripheral wall portion 14 is located in the tube outer peripheral wall portion 14 as shown in fig. 1(b), the thickness Ta thereof is present at a ratio of 90% or less, preferably 80% or less of the thickness Ts of the tube outer peripheral wall portion 14, and as the lower limit thereof, is present at a ratio of preferably 1% or more, more preferably 5% or more. That is, Ta.ltoreq.0.9 XTs and Ta.gtoreq.0.01 XTs are preferred. When the brazing material portion 18 exceeds 90% of the thickness Ts of the tube outer peripheral wall portion 14, the brazing material portion 18 melts during brazing heating, and the thickness of the tube outer peripheral wall portion 14 becomes too thin, which causes a problem such as a decrease in the pressure resistance of the flat multi-hole tube 10. Thus, the brazing material portion 18 is configured to be positioned on the outer surface side of the tube outer peripheral wall portion 14, so that the aluminum brazing material is exposed and present on the outer surface of the tube outer peripheral wall portion 14, and the outer surface brazeability can be favorably exhibited.
In the flat multi-hole tube 10 of the present invention, as described above, an Al — Si based aluminum alloy is used as the material of the aluminum brazing material constituting the brazing material portion 18, but it is advantageous to use an aluminum alloy containing 1.0 to 13.0 mass% of Si, 1.4 mass% or less of Mn (excluding 0 mass%), 0.05 to 0.30 mass% of Cr, 0.05 to 0.30 mass% of Zr, 0.05 to 0.30 mass% of Ti, and 0.0001 to 0.1 mass% of Sr, with the balance being aluminum and unavoidable impurities (e.g., Cu, Zn, Fe, etc.). Here, if the content of Si exceeds 13.0 mass%, the melting point is drastically lowered, and the base material may be melted during brazing heating. When the content of Si is less than 1.0 mass%, the brazeability is lowered. When the Mn content exceeds 1.4 mass%, there is a problem that deformation resistance during extrusion increases, and high-speed extrusion is difficult, and a pick-up (pick-up) phenomenon may occur during high-speed extrusion. Further, Cr, Zr, Ti and Sr are alloy components for increasing the grain size after brazing to improve brazeability, and when the content thereof is less than the above-specified range, the effect of adding these alloy components is insufficient, while when the content thereof is more than the above-specified range, coarse compounds in the extrusion material obtained by casting are significantly generated, thereby causing a problem of lowering the extrudability thereof. The lower limit of the alloy component Mn that is preferably contained in the Al — Si based aluminum alloy is generally about 0.1 mass%.
In the flat multi-hole tube 10 of the present invention, as the aluminum tube main body material constituting at least a part of the tube outer peripheral wall portion 14 and being a material other than the aluminum brazing material, an aluminum material conventionally used in the production of a flat multi-hole tube by extrusion processing can be used as it is, and for example, an a 1000-series pure aluminum material, an a 3000-series aluminum alloy material, or the like, which are known in JIS, can be suitably used, and further, in order to increase the potential thereof, a predetermined amount of Cu may be contained in these materials. Among these, as a material of the aluminum pipe main body material, it is advantageous to use an aluminum alloy containing 0.7 mass% or less (excluding 0 mass%) of Cu and 1.4 mass% or less (excluding 0 mass%) of Mn, and further containing at least one of 0.05 to 0.30 mass% of Cr, 0.05 to 0.30 mass% of Zr, 0.05 to 0.30 mass% of Ti, and 0.0001 to 0.1 mass% of Sr, with the balance being aluminum and unavoidable impurities (e.g., Si, Fe, Zn, etc.). Here, if the Cu content exceeds 0.7 mass%, there is a problem that deformation resistance during extrusion increases, and high-speed extrusion is difficult, and a pickup phenomenon may occur during high-speed extrusion. When the Mn content exceeds 1.4 mass%, the deformation resistance during extrusion increases, and high-speed extrusion is difficult, as in the case of Cu, and a pickup phenomenon may occur during high-speed extrusion. Further, Cr, Zr, Ti and Sr are alloy components for increasing the grain size after brazing to improve brazeability, and when the content thereof is less than the above-specified range, the effect of adding these alloy components is insufficient, while when the content thereof is more than the above-specified range, coarse compounds in the extrusion material obtained by casting are significantly generated, thereby causing a problem of lowering the extrudability thereof. In these alloy components, the lower limit of Cu is usually favorably 0.1 mass%, and the lower limit of Mn is usually favorably 0.1 mass%.
In the aluminum brazing material and the aluminum pipe main body material constituting the flat multi-hole pipe 10, the total content of aluminum and inevitable impurities (which are impurities including various elements such as Fe and Zn naturally contained in the material when the material is manufactured) which are the balance other than the above alloy components is limited to a range which is generally recognizable, and is controlled to be 0.5 mass% or less, preferably 0.3 mass% or less.
Further, the flat porous tube 10 of the present invention as described above is manufactured by using the above-described aluminum tube main body material and aluminum brazing material as the aluminum material for extrusion processing and simultaneously extruding these materials, and these aluminum tube main body material and brazing material are generally used using a composite billet of a core-sheath structure or a combination of a plurality of billets. Specifically, a composite preform of the following structure was used: an aluminum pipe body material having an optimized cross-sectional shape such as a circular shape, an oval shape, an elliptical shape, a rectangular shape, a half moon shape, a crescent shape, a polygonal shape, etc. and having an optimized cross-sectional dimension is disposed on an inner surface (central portion) of an aluminum brazing material, and these are joined and integrated by welding or the like, whereby a sheath portion composed of the above brazing material blank is formed around a core portion formed of the pipe body material blank.
In the production of the above-described composite material, various known means can be appropriately employed, and for example, the target composite material can be formed by the following method: a method in which a through hole having a predetermined size is formed in the center of a billet made of an aluminum brazing material to form a sheath billet, and a core billet made of an aluminum pipe body material is inserted into the through hole to be integrated; and a method of manufacturing such a sheath blank in a form of being divided into two halves, and then disposing a core blank in a hollow portion of the sheath blank divided into two halves, and fixing and integrating the whole by welding or the like in such a form; and so on.
Fig. 2(a) and (b) show an example of such a composite material, and here, the composite material 20 has the following structure: a cylindrical billet (sheath billet) 14 for brazing material is integrally disposed outside the cylindrical billet (core billet) 22 for tube body material.
In addition, the composite billet 20 can be subjected to hot extrusion processing by using a die having a plurality of extrusion ports (so-called split die) similar to the conventional production of an extruded flat multi-hole pipe, and the target extruded flat multi-hole pipe 10 can be obtained by applying the hot extrusion processing method, and in this case, the composite billet 20 is arranged and subjected to hot extrusion processing as follows: in a die having vertical extrusion ports arranged so as to correspond to the plurality of flow paths 12 of the flat multi-hole tube 10, the longitudinal direction of a predetermined cross-sectional shape of a tube main body material (22) arranged inside the composite billet 20 is made to coincide with the longitudinal direction of the extrusion ports of the die. By adopting the extrusion form of the composite billet 20 by the split segmented die, the brazing material (24) in the composite billet 20 can be efficiently distributed to the outer peripheral portion of the flat shape of the obtained flat perforated tube 10, and the brazing material portion can be favorably exposed on the tube outer peripheral surface.
However, when the above-described composite billet 20 is subjected to hot extrusion from a split die assembly by a conventional method to produce the intended flat multi-hole tube 10, the outer billet 24 of the composite billet 20 is entangled with the inner billet 22 of the tube body material, and the brazing material portion 18 in the formed flat multi-hole tube 10 easily enters the aluminum tube body material constituting the tube outer peripheral wall portion 14, so that corrosion occurs at the entering portion of the brazing material portion 18 during use of the fin material as a heat exchanger by brazing, and there is a possibility of causing leakage of fluid.
Thus, in the present invention, a method of extrusion processing from a split flow die in a form in which a predetermined disk-shaped front plate 26 is integrally disposed on the extrusion direction front end side (front side) of the composite billet 20 as shown in fig. 2(c) is advantageously employed, whereby the entanglement of the brazing material portions 18 at both end edge portions of the formed extruded flat multi-hole tube 10 can be effectively suppressed or prevented.
That is, in the extrusion process using such a front plate 26, the extrusion process is performed in a state where a circular or annular front plate 26 made of the same material as the aluminum pipe body material is fixed to the front end portion of the composite billet 20 by welding or the like, and the diameter of the front plate 26 is set to be in a range of 90% to 100% with respect to the diameter of the composite billet 20. If the diameter of the front plate 26 is larger than 100% of the diameter of the composite material 20, the composite material 20 may be hooked and may not be extruded when inserted into a container. Further, if the diameter of the front plate 26 is smaller than 90% of the diameter of the composite billet 20, the metal of the billet 22 for the aluminum pipe main body material positioned on the rear surface, the oxide film or foreign matter present on the outer surface layer of the billet, or the brazing material metal of the billet 24 for the brazing material, etc. are preferentially extruded from the gap during the extrusion process, and there is a possibility that a defective winding into both end portions of the extruded flat perforated pipe 10 occurs. The thickness of the front plate 26 is preferably 5% or more and 30% or less with respect to the diameter of the composite material 20. Among them, the ratio of 10% to 25% is most preferable. When the thickness of the front plate 26 is less than 5%, the range of the residual (dead metal) remaining in the container cannot be sufficiently filled with the front plate material, and there is a possibility that a poor entanglement of the brazing material layer into both end edge portions of the extruded flat multi-hole tube 10 occurs, and when the thickness of the front plate 26 exceeds 30%, the material ratio of the front plate 26 becomes too high, and there is a problem that the amount of the product to be discarded becomes large before the brazing material stably covers the outer surface of the extruded flat multi-hole tube 10.
As described above, the aluminum extruded flat multi-hole tube of the present invention can be suitably used as a refrigerant flow path member in a heat exchanger. In the case where the aluminum extruded flat multi-hole tube of the present invention is used as a refrigerant passage tube, for example, a heat exchanger is configured to have a structure including: a pair of aluminum header tanks (header tanks) disposed at a distance from each other; a plurality of aluminum extruded flat perforated pipes which are arranged in parallel with each other with a space in the longitudinal direction of the header tanks with the width direction thereof facing the ventilation direction, between the two header tanks, and both ends of which are connected to the two header tanks; aluminum corrugated fins as external fins disposed between adjacent flat perforated tubes and outside the flat perforated tubes at both ends thereof, and brazed to these flat perforated tubes; and aluminum side plates which are disposed outside the corrugated fins at both ends and are brazed to the fins. Of course, it goes without saying that the aluminum extruded flat multi-hole tube of the present invention may be used as a refrigerant passage tube in various known heat exchangers other than the heat exchanger having such a structure.
In addition, as is well known, in the case of a pair of header tanks in a heat exchanger, refrigerant or coolant is distributed from one header tank to flow into flat perforated tubes, and the refrigerant or coolant flowing out of the flat perforated tubes is collected in the other header tank, and for example, it is known to use: a structure in which header plates (header plates) are brazed to face each other; a structure in which a plate is bent into a tubular shape and the overlapped ends are welded or brazed; and an extruded tube extruded in a tubular shape; and so on.
While representative embodiments of the present invention have been described in detail, it should be understood that these are merely exemplary and that the present invention should not be construed as being limited to the specific descriptions of such embodiments.
The present invention can be implemented by adding various alterations, modifications, improvements, and the like to the embodiments based on the knowledge of those skilled in the art, and it is needless to say that such embodiments fall within the scope of the present invention as long as they do not depart from the gist of the present invention.
Examples
Hereinafter, the present invention will be described more specifically by showing representative examples thereof, but it should be understood that the present invention is not limited to such examples.
First, as materials for producing various flat multi-hole tubes, various aluminum brazing material billets a to R having a composition shown in table 1 below and various aluminum tube main body material billets a to o having a composition shown in table 3 below were cast, and then, these billets were combined in various ways to produce various composite billets B1 to B32 shown in table 5 below, and further, these composite billets were subjected to hot extrusion processing, respectively, thereby obtaining various flat multi-hole tubes T1 to T32 corresponding to these composite billets shown in table 5 below. In addition, the same operation was carried out, and billets S to AA for aluminum brazing material having the composition shown in table 2 below and billets p to u for aluminum pipe body having the composition shown in table 4 below were cast, and then, these billets were combined in various ways to produce various composite billets B33 to B52 and single billet B53 shown in table 6 below, and further, these composite billets and single billets were subjected to hot extrusion processing, respectively, to thereby obtain various flat porous pipes T33 to T53 corresponding to these billets shown in table 6 below.
Then, using the thus obtained various flat multi-hole tubes T1 to T53, the following (1) evaluation of presence or absence of entanglement failure of the brazing material layer, (2) measurement of length of the poor covering portion, (3) measurement of formation range of the brazing material portion, and (4) evaluation of failure at the time of assembling the heat exchanger core were carried out, respectively.
[ Table 1]
Figure BDA0002164011540000141
Contains inevitable impurities
[ Table 2]
Figure BDA0002164011540000151
Contains inevitable impurities
[ Table 3]
Figure BDA0002164011540000161
Contains inevitable impurities
[ Table 4]
Figure BDA0002164011540000171
Contains inevitable impurities
[ Table 5]
Figure BDA0002164011540000181
[ Table 6]
Figure BDA0002164011540000191
Specifically, first, in order to form the brazing material portions 18, the alloy components were adjusted to provide the aluminum brazing material billets a to R shown in table 1 and the aluminum brazing material billets S to AA shown in table 2, respectively, and the billets were prepared by a conventional method
Figure BDA0002164011540000192
Various DC cast billets. On the other hand, DC cast billets were produced in the same manner as described above so as to provide billets a to o for aluminum pipe main body shown in table 3 and billets p to u for aluminum pipe main body shown in table 4 by adjusting the alloy components for forming the pipe main body, and the obtained billets were formed into cylinders having a predetermined size in a circular size range of 5mm to 85 mm.
Further, a through hole into which the processed tube body material billet can be inserted is formed in the center of the cross section of the brazing material billet, the tube body material billet is inserted into the through hole, and the brazing material billet and the tube body material billet are fixed and joined by MIG welding at both end surfaces in the longitudinal direction thereof, and the composite billets B1 to B32 and B33 to B52 shown in table 5 and table 6 are respectively manufactured into an integrated composite billet 20 having the cross sectional form shown in fig. 2. The extrusion billet B53 shown in table 6 is a single billet shown as 30 in fig. 3 formed only from a billet for a tube body material. In fig. 2 and 3, 22 and 32 are blanks for the tube main body material, and 24 is a blank for the brazing material.
Next, as shown in fig. 2(c) or 3(c), a disk-shaped front plate 26 having various dimensions (both diameter and thickness are shown as percentages with respect to the diameter of the composite billet) shown in tables 5 and 6 was fixed to the extrusion direction front end face of the obtained composite billet 20 or single billet 30 by fusion, the billet-front plate assembly was heated to 500 ℃ by a billet heater, and then hot extrusion was performed from the front plate 26 side using an extrusion port having rectangular holes (6 flow paths) for forming 6 holes and a split die similar to the conventional one, whereby flat porous pipes T1 to T32 and T33 to T53 (entire thickness: 2.0mm, width in the flat direction: 16mm, wall thickness of the pipe outer peripheral wall portion and partition wall portion: 0.25mm) of the 6 holes shown in tables 5 and 6 corresponding to the respective extrusion billets were produced. When the flat multi-port tube T48 was produced by hot extrusion using the composite billet B48, the billet clogged in the container, and therefore, the hot extrusion could not be performed, and thus the production could not be performed.
(1) Evaluation of defective roll-in of brazing material layer
The 6-hole flat multi-hole tubes (10) thus obtained were cut at a position of 1/2 in the extrusion longitudinal direction, and the cross sections thereof were observed. Specifically, the microstructure of the cross section is photographed at a magnification of 25 times, and the state of entanglement of the brazing material part (18) at both end edge parts of the flat multi-hole tube (10) is examined to evaluate the presence or absence of entanglement failure. Further, the case where the solder portion (18) was not confirmed at either of both end edge portions was evaluated as "o", and the case where the solder portion (18) was confirmed at the end edge portion side was evaluated as "x".
Tables 7 and 8 below show the results of evaluating the above-described defective entanglement of the brazing material portions (18) with respect to the flat multi-hole tubes T1 to T32 and the flat multi-hole tubes T33 to T53, respectively. Note that, the flat perforated tube T48 was not evaluated because the hot extrusion process was terminated halfway.
The results of this cross-sectional observation are: in the flat multi-hole tubes T1 to T32 obtained by the above extrusion processing, no trouble of entanglement of the brazing material portion (18) in the tube end edge portion was observed in any of them.
On the other hand, in the flat multi-hole tubes T33, T34 and T53 obtained by using the composite billets B33 and B34 and the single billet B53 and performing the hot extrusion processing by the split combined die, since billets of conventional alloys containing no brazing material component or pure Al-based alloys were used, there was no brazing material portion (18) and no trouble of entanglement of the brazing material portion (18) was observed at both tube end portions. In the flat multi-hole tubes T35 to T47, T50, and T52, the entanglement of the brazing material portion (18) was similarly not observed. However, in both of the flat perforated tubes T49 and T51: a trouble of rolling in the brazing material part (18) occurs at both end edge parts. From these cases, it was found that: since the diameter and thickness of the used front plate are insufficient, an oxide film or foreign matter on the surface layer of the billet for the tube body located on the rear side in the extrusion direction preferentially flows in, and a metal such as a brazing material of the billet for the brazing material preferentially flows in, and thus a defective entrainment of the brazing material portion (18) occurs at both end portions in the width direction of the flat multi-hole tube.
(2) Length measurement of poorly covered section
The lengths of the poor coating portions were measured using the flat multi-hole tubes T1 to T32 and T33 to T53 obtained above, respectively. Note that, since the flat multi-hole tubes T33, T34, and T53 were formed of conventional alloys or pure Al alloys without using billets containing brazing material components, no brazing material portions (18) were formed, and further, the flat multi-hole tube T48 was not evaluated because it could not be manufactured due to suspension of the hot extrusion process.
Specifically, the flat perforated tubes T1 to T32 and T33 to T53 were subjected to cross-sectional observation over the entire length thereof at a pitch of 1.0m in the extrusion direction after the respective hot extrusion processes, and the length of the poor covering portion (only the portion of the front plate material, the portion where the coverage is excessively large due to the influence of the front plate material) was measured. In the measurement of the length of the poor coating portion, a case where the length of the poor coating portion is 15m or less was evaluated as "o", and a case where the length exceeds 15m was evaluated as "x", and the results are shown in tables 7 and 8 below.
[ Table 7]
Figure BDA0002164011540000221
[ Table 8]
Figure BDA0002164011540000231
From the results shown in table 7, it was confirmed that the lengths of the poor coating portions of the flat multi-hole tubes T1 to T32 were all 15m or less, and the entanglement of the brazing material layer was effectively suppressed.
On the other hand, in the flat multi-hole tubes T33, T34, and T53, since each of the tubes was obtained using a billet containing no brazing material component, the existence of any poor coating portion was not found, and in the flat multi-hole tubes T35 to T47 and T52, although a poor coating portion was confirmed, the length of the poor coating portion was 15m or less. However, the flat perforated tubes T49 to T51 confirmed that the length of the poor coating portion exceeded 15m, and particularly, the flat perforated tube T51 confirmed that the poor coating portion was present over the entire length (about 60m) up to the extrusion tail of the completion of the extrusion.
(3) Measurement of Forming Range of solder portion
The 6-hole flat multi-hole tubes (10) obtained above were cut at a position of 1/2 in the extrusion length direction, and the cross sections thereof were observed. That is, the formation range of the solder part (18) is measured by measuring the area of the solder part (18) with a ruler using a photograph obtained by photographing the microstructure of the cross section at a magnification of 25 times. In the measurement of the formation range of the brazing material portion (18), a case where the formation range of the brazing material portion (18) is 100% or less and 50% or more of the circumferential length L of the outer peripheral portion of the tube is evaluated as "", and a case where the formation range is less than 50% of the circumferential length is evaluated as "×". The thickness of the brazing material portion (18) in the outer peripheral wall portion (14) of the tube is 90% or less of the thickness of the outer peripheral wall portion (14) of the tube, and the thickness exceeding 90% is evaluated as (. smallcircle.).
In tables 9 and 10 below, the results of measuring the formation ranges of the above-described brazing material portions (18) for the flat multi-hole tubes T1 to T32 and T33 to T53 are shown as the value at which the circumferential length of the brazing material portions (18) exposed to the outer peripheral portion of the tube becomes minimum and the maximum thickness of the brazing material portions (18) in the outer peripheral wall portion (14) of the tube.
[ Table 9]
Figure BDA0002164011540000251
[ Table 10]
Figure BDA0002164011540000261
The results of this cross-sectional observation confirmed: in the flat multi-hole tubes T1 to T32 obtained by the extrusion processing, the brazing material part (18) formed by the brazing material blank is exposed in a proportion of 50% to 100% of the circumference L of the outer circumference of the tube. Further, it was found that the thickness of the brazing material portion (18) formed in the outer peripheral wall portion (14) of the tube was present in a range of 90% or less of the thickness of the outer peripheral wall portion (14) of the tube, and was exposed to the outer surface of the tube. In addition, it was confirmed that the flat multi-hole tube (10) obtained by the hot extrusion was stable in the outer surface of the outer peripheral portion of the tube in the brazing material portion (18) formed of the brazing material billet in the extrusion length direction.
On the other hand, in the flat multi-hole tubes T33, T34 and T53 obtained by hot extrusion processing using the split dies using the composite billets B33 and B34 and the single billet B53, since billets made of conventional alloys containing no brazing material component or pure Al-based alloys are used, there is no brazing material portion (18), and therefore, exposure of the outer surface of the tube is not observed. In addition, in the flat multi-hole tube T51 obtained using the composite billet B51 shown in table 6, the exposed portion of the brazing material portion (18) was 100% of the outer peripheral portion circumference L of the tube, and the thickness of the outer peripheral wall portion (14) of the tube was 93% at the thickest portion. In addition, in the flat multi-hole tubes T35 to T47, T49, T50, and T52 obtained by using the composite blanks B35 to B47, B49, B50, and B52 shown in table 6 and using the above method, the exposed portions of the brazing material portions (18) are all 50% or less of the outer peripheral portion circumference L of the tube, and the thickness of the outer peripheral wall portion (14) of the tube is 10 to 20% at the thickest portion. Note that, regarding the flat multi-hole tube T48, the composite billet B48 shown in table 6 was plugged at the time of hot extrusion processing, and the target flat multi-hole tube was not obtained, and therefore, evaluation was not performed.
(4) Evaluation of failure in assembling Heat exchanger core
The flat multi-hole tubes T1 to T32 and T33 to T53 obtained above were used as test materials, and the occurrence of defects in the production of a heat exchanger core was evaluated by attaching fins to the respective flat multi-hole tubes and performing brazing heating.
Specifically, bare fins 80 μm thick corrugated to a size of 3mm in fin pitch and 7mm in fin height were attached to each of the flat porous tubes T1 to T32 and T33 to T53, and when they were used as heat transfer tubes in a heat exchanger, heat treatment of 600 ℃x3 minutes was performed by heating for fin joining, and brazing was performed to form a heat exchanger core, and then the fins joined to the flat porous tubes in each heat exchanger core were cut and removed by a cutter, and the joining condition of the fins and the occurrence condition of defects in the flat porous tubes were visually confirmed.
Tables 11 and 12 below show the results of verifying the state of fin junction of the heat exchanger core after brazing and the occurrence of defects in the flat multi-hole tubes, respectively, when the heat exchanger core was produced using the flat multi-hole tubes T1 to T32 and T33 to T53 as test materials.
[ Table 11]
Kind of flat perforated pipe Bad conditions in core body manufacturing Evaluation of
T1 Is not confirmed to ○
T2 Is not confirmed to ○
T3 Is not confirmed to ○
T4 Is not confirmed to ○
T5 Is not confirmed to ○
T6 Is not confirmed to ○
T7 Is not confirmed to ○
T8 Is not sureRecognize that ○
T9 Is not confirmed to ○
T10 Is not confirmed to ○
T11 Is not confirmed to ○
T12 Is not confirmed to ○
T13 Is not confirmed to ○
T14 Is not confirmed to ○
T15 Is not confirmed to ○
T16 Is not confirmed to ○
T17 Is not confirmed to ○
T18 Is not confirmed to ○
T19 Is not confirmed to ○
T20 Is not confirmed to ○
T21 Is not confirmed to ○
T22 Is not confirmed to ○
T23 Is not confirmed to ○
T24 Is not confirmed to ○
T25 Is not confirmed to ○
T26 Is not confirmed to ○
T27 Is not confirmed to ○
T28 Is not confirmed to ○
T29 Is not confirmed to ○
T30 Is not confirmed to ○
T31 Is not confirmed to ○
T32 Is not confirmed to ○
[ Table 12]
Kind of flat perforated pipe Bad conditions in core body manufacturing Evaluation of
T33 The fins are not engaged ×
T34 The fins are not engaged ×
T35 Melting of parent material ×
T36 The fins are not engaged ×
T37 The situation that the fins are not jointed is more ×
T38 The situation that the fins are not jointed is more ×
T39 The situation that the fins are not jointed is more ×
T40 The situation that the fins are not jointed is more ×
T41 The situation that the fins are not jointed is more ×
T42 The situation that the fins are not jointed is more ×
T43 The situation that the fins are not jointed is more ×
T44 The situation that the fins are not jointed is more ×
T45 The situation that the fins are not jointed is more ×
T46 The situation that the fins are not jointed is more ×
T47 The situation that the fins are not jointed is more ×
T48 Can not be extruded -
T49 Through hole from roll part ×
T50 The situation that the fins are not jointed is more ×
T51 Through hole from roll-in part and peripheral wall part ×
T52 The situation that the fins are not jointed is more ×
T53 The fins are not engaged ×
From the results in table 11, it is understood that the flat multi-hole tubes T1 to T32 did not have any fin bonding failure in the heat exchanger core after brazing heating, and did not have any failure in the flat multi-hole tubes. Therefore, it was found that the flat multi-hole tubes T1 to T32 each exhibited a favorable fin joining form due to the presence of the brazing material portion (18), and were excellent as flat multi-hole tubes for brazing.
In contrast, in all of the flat multi-hole tubes T33, T34, and T53 shown in table 12, only the conventional material containing no brazing material component and the material made of a pure Al alloy were used, and therefore, the fins were not joined to the heat exchanger core after brazing heating. In addition, since the Si content as the brazing material component was 0 mass%, the fins were not joined to the flat multi-hole tube T36. In addition, in the flat multi-hole tube T35 shown in table 12, since the Si content was 14.0 mass% and the content thereof was large, the brazing material portion (18) was melted during brazing heating, and through holes were found in the base material due to the melting. In addition, the flat perforated tubes T37 to T47, T50, and T52 were found to have wide unjoined portions although some of the fins were joined. In the flat multi-hole tubes T49 and T51, the brazing material layer was found to be insufficiently entangled in the corners at both ends, and the brazing material portions (18) were found to melt during brazing heating, resulting in through-holes. In particular, in the flat multi-hole tube T51, the tube outer peripheral wall portion (14) was also melted in addition to the defective portion of entanglement of the brazing material layer generated in both end portions of the flat multi-hole tube, and a through-hole was found by the melting.
Description of the reference numerals
10 flow path of flat multi-hole tube 12
14 outer peripheral wall 16 inner partition wall
18 brazing material part 20 composite blank
22-pipe body material billet 24 brazing material billet
26 front plate 30 single blank
Blank 34 front plate for 32-tube body material

Claims (10)

1. An aluminum extruded flat porous tube having excellent brazeability, which is an extruded tube having a flat cross-sectional shape as a whole obtained by extrusion processing of an aluminum material, and which has a plurality of flow paths extending independently in parallel to the tube axial direction and arranged in the longitudinal direction of the flat cross-sectional shape with an internal partition wall portion extending in the tube axial direction interposed therebetween,
the aluminum extruded flat multi-hole tube is formed by extrusion processing using an aluminum tube main body material and an aluminum brazing material formed of an aluminum alloy containing 1.0 to 13.0 mass% of Si, one or two or more of 1.4 mass% or less of Mn, 0.05 to 0.30 mass% of Cr and 0.05 to 0.30 mass% of Ti, one or two or more of 0.05 to 0.30 mass% of Zr and 0.0002 to 0.1 mass% of Sr, with the balance being aluminum and unavoidable impurities,
the aluminum brazing material is exposed over the entire area of the tube outer peripheral wall portion or at least a part of the flat portion in the tube outer peripheral wall portion to form a brazing material portion, and the brazing material portion is present at a ratio of 50% or more and 100% or less of the circumference of the tube outer peripheral wall portion in the tube cross section, while the brazing material portion located at the tube outer peripheral wall portion is present at a ratio of 90% or less of the thickness of the tube outer peripheral wall portion.
2. The aluminum extruded flat multi-hole tube having excellent brazeability as claimed in claim 1, wherein said aluminum tube body material is formed of an aluminum alloy containing 0.7 mass% or less of Cu, 1.4 mass% or less of Mn and 0.0002 to 0.1 mass% of Sr, and further containing one or two or more of 0.05 to 0.30 mass% of Cr, 0.05 to 0.30 mass% of Zr and 0.05 to 0.30 mass% of Ti, with the balance being aluminum and inevitable impurities.
3. The aluminum extruded flat porous tube having excellent brazeability as claimed in claim 1 or 2, wherein the extruded aluminum material is a composite billet composed of the aluminum tube main body material and the aluminum brazing material.
4. The aluminum extruded flat porous tube with excellent brazeability as claimed in claim 3, wherein said composite billet has an integral core-sheath structure comprising a core billet formed of the aluminum tube main body material and a sheath billet formed of the aluminum brazing material located around the core billet.
5. The aluminum extruded flat perforated pipe having excellent brazeability as claimed in claim 1 or 2, wherein the extruded pipe is formed by extrusion processing of the aluminum material using a split flow die assembly.
6. The aluminum extruded flat perforated tube having excellent brazeability as claimed in claim 3, wherein the extruded tube is formed by extrusion processing of the aluminum material using a split-flow segmented die.
7. The aluminum extruded flat perforated tube having excellent brazeability according to claim 4, wherein the extruded tube is formed by extrusion processing of the aluminum material using a split-flow die assembly.
8. A method for producing an aluminum extruded flat multi-hole tube having excellent brazeability, which is the method for producing the aluminum extruded flat multi-hole tube described in any one of claims 1 to 7,
the method comprises using a composite billet composed of an aluminum pipe body material and an aluminum brazing material, and a front plate made of the same material as the aluminum pipe body material, wherein the aluminum brazing material is formed of an Al-Si-based aluminum alloy, the front plate is arranged on the front side in the extrusion direction of the composite billet so that the diameter of the front plate is 90% or more and 100% or less with respect to the diameter of the composite billet, and the thickness of the front plate is 5% or more and 30% or less with respect to the diameter of the composite billet, and the front plate and the composite billet are extruded together using a split die.
9. The method for manufacturing an aluminum extruded flat porous tube excellent in brazeability as claimed in claim 8, wherein said composite billet has an integral core-sheath structure comprising a core billet formed of the aluminum tube main body material and a sheath billet formed of the aluminum brazing material located around the core billet.
10. An aluminum heat exchanger, characterized by comprising the aluminum extruded flat multi-hole tube as recited in any one of claims 1 to 7, and an aluminum external fin brazed to an outer surface of the aluminum extruded flat multi-hole tube.
CN201880011508.8A 2017-02-13 2018-02-08 Aluminum extruded flat multi-hole tube having excellent brazeability and method for manufacturing the same Active CN110290882B (en)

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CN118080852B (en) * 2024-04-19 2024-08-13 上海华峰铝业股份有限公司 Extrusion device and preparation method of aluminum alloy self-brazing filler metal plate

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