WO2018147376A1

WO2018147376A1 - Aluminum extruded flat perforated pipe exhibiting excellent brazing properties, and method for producing same

Info

Publication number: WO2018147376A1
Application number: PCT/JP2018/004424
Authority: WO
Inventors: 中村　真一; 尚希山下; 英敏熊谷; 永尾　誠一
Original assignee: 株式会社Uacj; 株式会社Ｕａｃｊ押出加工
Priority date: 2017-02-13
Filing date: 2018-02-08
Publication date: 2018-08-16
Also published as: CN110290882B; CN110290882A; JPWO2018147376A1; DE112018000796T5

Abstract

The present invention effectively increases the excellent outer-surface brazing properties of an aluminum extruded flat perforated pipe, and provides a method for inexpensively, simply and advantageously producing the same. An aluminum extruded flat perforated pipe 10 formed by simultaneously extruding an aluminum pipe main body material and a brazing material comprising an Al-Si-based aluminum alloy, wherein a brazing material 18 section is formed by exposing the brazing material around the entirety of the pipe outer-circumferential wall section or at least part of the flat section of the pipe outer-circumferential wall section.

Description

Aluminum extruded flat multi-hole tube having excellent brazing properties and manufacturing method thereof

The present invention relates to an aluminum extruded flat multi-hole tube having excellent brazing properties and a method for producing the same, and in particular, it can be suitably used as a heat exchanger, in particular, a heat transfer tube of an automotive heat exchanger such as a car air conditioner. Aluminum extruded flat multi-holes for heat exchangers with stable and uniform brazing by providing a brazing material part stably and inexpensively to the outer peripheral part of an aluminum extruded flat multi-hole pipe to which fins are brazed and joined It relates to a tube and a method for producing it advantageously.

Conventionally, an aluminum extruded flat multi-hole tube having a flat cross-sectional shape as a whole obtained by extrusion processing of an aluminum material has been used as a refrigerant passage tube in an automobile heat exchanger, and refrigerant is introduced into the refrigerant passage tube. The heat exchanger is constructed by assembling and brazing and fixing aluminum fins in a direction perpendicular to the refrigerant passage tube while allowing air as a heat exchange fluid to flow along the fins. By flowing, heat exchange is performed between the refrigerant and the air. For such aluminum extruded flat multi-hole tubes, conventionally, aluminum fins made of a brazing sheet clad with an Al-Si alloy brazing material are used, and this is used for flux brazing or vacuum brazing. Alternatively, it is assembled by brazing and joining by fluxless brazing such as atmospheric brazing.

By the way, in recent years, from the viewpoint of reducing the weight of an aluminum heat exchanger, it has been required to reduce the thickness of the aluminum fin material. In this case, the fin material is changed from a brazing sheet to a bare material, contrary to the conventional case. If the brazing material can be coated, further thinning of the fin material can be expected. However, the present situation is that a method for stably and inexpensively coating a brazing material on an aluminum extruded flat multi-hole tube on an industrial scale has not been established.

Therefore, as a method applicable to the brazing material coating on the aluminum extruded flat multi-hole tube, after the aluminum extruded flat multi-hole tube is immersed in a mixture of flux and silicon metal powder, or the mixture is applied. , By heating and drying, the mixture is applied to the outer surface of an aluminum extruded flat multi-hole tube, combined with the bare material, and heated in a brazing furnace to be alloyed. In addition, a method of performing brazing by forming an Al—Si-based molten brazing on the joint surfaces (JP-A-6-504485, JP-A-7-308795) has been proposed, These methods are cumbersome to apply or coat, and are costly, uniform coating is difficult, and the adhesion of Si powder tends to be insufficient. There is a drawback that brazing is hard do. Furthermore, although a technique for spraying a brazing material onto an aluminum extruded flat multi-hole tube (Japanese Patent Laid-Open No. 2002-172485) has been proposed, it is very difficult to coat uniformly and it is necessary to introduce new equipment. There is a problem of high costs. In order to solve these problems, it is considered effective to use an extruded flat multi-hole tube whose outer surface is stably and uniformly clad with a brazing material.

On the other hand, as extruded flat multi-hole tubes, those obtained by port hole extrusion of aluminum or an aluminum alloy are usually used. JP-A-10-258356 discloses such an aluminum extruded flat multi-hole tube. A technique has been proposed in which a brazing material is clad in a hole tube during extrusion. However, there is a problem that the clad brazing filler metal layer is wound around both end edges of the aluminum extruded flat multi-hole tube, and the brazing filler metal layer is liable to be caught. In order to solve this problem, Japanese Patent Application Laid-Open No. 10-197175 also proposes forming protrusions on both side edges of the tube, but the protrusions on both side edges of the aluminum extruded flat multi-hole tube. Since there is a need to provide a shape restriction, there is a problem that the versatility is extremely low because the shape is restricted.

Further, in Japanese Patent Laid-Open No. 63-97309, a composite billet composed of an aluminum core material forming material and a skin material forming material made of an Al—Si based aluminum brazing alloy material is simultaneously extruded. A method of manufacturing a clad pipe in which a brazing filler metal layer is clad with respect to the outer flat part of the pipe peripheral wall part has been proposed. Even in such a clad pipe, the metal flow of the skin material forming material is proposed. When the position of the composite billet and the port hole of the port hole die is slightly shifted due to the influence, the brazing filler metal layer is caught in the welded part, and there is an inherent problem such as defective winding. Met.

JP-T 6-504485 Japanese Patent Laid-Open No. 7-308795 JP 2002-172485 A Japanese Patent Laid-Open No. 10-258356 Japanese Patent Laid-Open No. 10-197175 JP-A-63-97309

Under such circumstances, in order to join other aluminum members such as aluminum fins to the outer periphery of the aluminum extruded flat multi-hole tube obtained by extruding aluminum material, the present inventors As a result of intensive investigations to stably and inexpensively provide an Al-Si brazing filler metal layer that forms molten brazing on the surface, as an aluminum material to be extruded, an ordinary aluminum tube body material and an Al-Si alloy The aluminum brazing material made of Al—Si alloy is advantageously exposed to the outer peripheral portion of the obtained aluminum extruded flat multi-hole tube by simultaneously extruding the aluminum brazing material comprising It was found that the aluminum tube body material and Al-Si which are hot extruded By installing a predetermined front plate in the forward direction of the composite billet in combination with an aluminum brazing material composed of the above, a brazing material layer is effectively restrained from entraining at both ends of the extruded flat multi-hole tube. It can be applied to general extruded flat multi-hole pipes that are generally used, so it is found that it has excellent versatility, thereby exposing a uniform brazing material layer easily and inexpensively. It has been found that it can be formed without defects in its entrainment.

Therefore, the present invention has been completed based on such knowledge, and the problem to be solved is an aluminum extruded flat having an overall flat cross-sectional shape obtained by extrusion processing of an aluminum material. The object of the present invention is to provide an aluminum extruded flat multi-hole tube having excellent outer surface brazing properties at a simple and low cost, and another object is to provide aluminum that can exhibit such excellent characteristics. An object of the present invention is to provide a method for advantageously producing an extruded flat multi-hole tube.

In order to solve such problems, the present invention is an extruded tube having a flat cross-sectional shape as a whole obtained by extrusion of an aluminum material, and is independent of each other in the tube axis direction. Aluminum extrusion flat multi-holes having a plurality of flow paths extending in parallel and arranged in the longitudinal direction of a flat cross-sectional shape via internal partition walls extending in the tube axis direction. The tube is formed by extrusion using an aluminum tube main body material and an aluminum brazing material made of an Al-Si based aluminum alloy as the aluminum material, and at least over the entire outer peripheral wall portion of the tube. The aluminum brazing material is exposed to a part of the flat portion of the outer peripheral wall portion of the tube to form a brazing material portion, and the brazing material portion is crossed by the tube. 50% or more and 100% or less of the peripheral length of the outer peripheral wall portion of the pipe, while the brazing filler metal portion located on the outer peripheral wall portion of the pipe is 90% or less of the thickness of the outer peripheral wall portion of the pipe. Therefore, the gist of the present invention is an aluminum extruded flat multi-hole tube having excellent brazing characteristics characterized by being present in the above ratio.

According to one of the desirable embodiments of the aluminum extruded flat multi-hole tube having excellent brazing properties according to the present invention, the aluminum brazing material contains Si: 1.0 to 13.0% by mass, Further, Mn: 1.4 mass% or less, Cr: 0.05 to 0.30 mass%, Zr: 0.05 to 0.30 mass%, Ti: 0.05 to 0.30 mass%, and Sr: 0 An aluminum alloy containing one or more of 0.0001 to 0.1% by mass and the balance being aluminum and unavoidable impurities is used. On the other hand, the aluminum tube body material is Cu: 0.7 Containing 0.3% by mass or less and Mn: 1.4% by mass or less, Cr: 0.05 to 0.30% by mass, Zr: 0.05 to 0.30% by mass, Ti: 0.05 to 0.3%. 30% by mass and Sr: 0.0001- Containing one or more of .1 wt%, so that the aluminum alloy the remainder being aluminum and inevitable impurities is used.

Also, according to one of the preferred embodiments of the aluminum extruded flat multi-hole tube having excellent brazing properties according to the present invention, the aluminum material to be extruded is composed of the aluminum tube main body material and the aluminum brazing material. A composite billet will be used.

Furthermore, in another preferred embodiment of the present invention, the composite billet is a core billet made of the aluminum tube main body material, and a sheath billet made of the aluminum brazing material located around the core billet. Has an integral core-sheath structure.

In addition, in an advantageous aspect of the aluminum extruded flat multi-hole tube having excellent brazing properties according to the present invention, the extruded tube is formed by extrusion of the aluminum material using a porthole die. ing.

Further, in order to advantageously manufacture such an aluminum extruded flat multi-hole tube according to the present invention, in the present invention, a composite composed of an aluminum tube main body material and an aluminum brazing material made of an Al—Si based aluminum alloy is used. A front plate made of the same material as the aluminum tube body material is used together with the billet, and the diameter of the front plate is set to 90% or more and 100% or less with respect to the diameter of the composite billet, and the thickness of the front plate is further increased. The front plate is arranged on the front side in the extrusion direction of the composite billet, and the front plate and the composite billet are connected to the port hole die. The gist of the present invention is also a method for producing an aluminum extruded flat multi-hole tube having excellent brazing properties characterized by being extruded together.

Furthermore, in the method for producing an aluminum extruded flat multi-hole tube according to the present invention, advantageously, the composite billet is positioned around the core billet, the core billet made of the aluminum tube main body material. It has an integral core-sheath structure consisting of a sheath billet made of an aluminum brazing material.

And in this invention, it is comprised including the aluminum extrusion flat multi-hole pipe | tube according to this invention as mentioned above, and the aluminum outer fin brazed and joined to the outer surface of this aluminum extrusion flat multi-hole pipe | tube. The gist of the present invention is also an aluminum heat exchanger.

Thus, in the aluminum extruded flat multi-hole tube configured according to the present invention, a brazing material portion made of an aluminum brazing material is provided over the entire outer periphery of the tube or at least a part of the flat portion of the outer periphery of the tube. A heat exchanger that is exposed and has an effective brazing property to the outer surface side of the tube, such as a radiator and heater, without the brazing filler metal layer being wound around both ends of the extruded flat multi-hole tube. As a heat transfer tube, it can be advantageously used.

Moreover, the aluminum extruded flat multi-hole tube according to the present invention is composed of an aluminum tube main body material and an aluminum brazing material, and is formed directly by simultaneous extrusion of these two materials. The brazing performance can be effectively demonstrated in the aluminum brazing material while ensuring the characteristics of the aluminum tube main body material. There is also an advantage that can be advantageously increased.

Furthermore, according to the method for producing an aluminum extruded flat multi-hole tube having excellent brazing properties according to the present invention, the extrusion direction of a composite billet composed of an aluminum tube main body material and an aluminum brazing material made of an Al—Si based aluminum alloy Effectively suppresses or prevents the aluminum brazing material from being caught in the aluminum tube body material because it is extruded from the port hole die in a state where a predetermined front plate is disposed in front. The aluminum extruded flat multi-hole having a stable quality in terms of brazing without the brazing filler metal layer being wound around both ends of the extruded flat multi-hole tube thus obtained. The tube could be advantageously obtained.

In addition, in an aluminum heat exchanger constructed by assembling an aluminum extruded flat multi-hole tube according to the present invention and an aluminum outer fin (bare fin) and joining them by brazing heating, the aluminum By using an extruded flat multi-hole tube in which the brazing material is exposed, the brazing and fixing of the aluminum outer fin can be advantageously realized, and the intended heat exchanger can be obtained easily and inexpensively. .

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional explanatory drawing which shows typically an example of the aluminum extrusion flat multi-hole tube according to this invention, Comprising: (a) shows the whole figure, (b) expands a part of the width direction center part. (C) is explanatory drawing which expands and shows a part of width direction edge part in the example whose brazing | wax material part is a different exposure ratio. It is explanatory drawing about the composite billet used in the Example, (a) And (b) is a figure which shows the cross section and the longitudinal cross section, respectively, (c) is the state which installed the front board It is explanatory drawing which shows the longitudinal cross-section of a composite billet. It is explanatory drawing about the single billet used in the Example, (a) And (b) is a figure which shows the cross section and the longitudinal cross section, respectively, (c) is the state which installed the front board It is explanatory drawing which shows the longitudinal cross-section of a single billet.

Hereinafter, in order to clarify 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 multi-hole pipe according to the present invention in the form of a cross section that is a cross section perpendicular to the longitudinal direction (tube axis direction). Yes. The flat multi-hole tube 10 according to the present invention is an extruded tube of an aluminum material having a flat cross-sectional shape as a whole as shown in FIG. And a plurality of rectangular flow paths 12 extending in parallel with each other, and the plurality of flow paths 12 are arranged at predetermined intervals in a flat longitudinal direction (left-right direction in the drawing) that is a tube width direction. It is a structure that is damped. Note that the upper and lower surfaces of the flat multi-hole tube 10 facing each other are flat surfaces, and there are outer fins (not shown) such as plate fins and corrugated fins as bare fins. Used to be attached by a brazing joint technique and can be used as a heat exchanger. In addition, although the cross-sectional shape of the flow path 12 is a rectangular shape here, it is possible to adopt a known circular shape, an elliptical shape, a triangular shape, or a combination of these shapes. Is possible.

In the present invention, in the flat multi-hole tube 10 having such a structure, as is apparent from FIGS. 1A to 1C, the internal partition located between the

adjacent flow paths

12 and 12 is used. While the periphery of the flow path 12 including the portion 16 is made of a normal aluminum tube main body material, a flat surface that gives at least the flat surface of the tube outer peripheral wall portion 14 out of the entire circumference of the tube outer peripheral wall portion 14. A layer of a brazing filler metal portion 18 made of an aluminum brazing material is present in a part of the portion, and this brazing filler metal portion 18 is formed on at least a part of the outer peripheral surface of the pipe outer peripheral wall portion 14 (here, on the entire outer peripheral surface). ), It can be exposed. Thus, by arranging the brazing filler metal portion 18 on the pipe outer peripheral wall portion 14, the brazing filler metal component of the aluminum brazing material constituting the brazing filler metal portion 18 is used to exhibit excellent brazing properties. The flat multi-hole tube 10 can be obtained.

By the way, the brazing filler metal part 18 as described above is exposed on the outer surface side of at least a part of the pipe outer peripheral wall part 14 of the flat part (flat surface) of the total length L of the pipe in the cross section of the flat multi-hole pipe 10. The exposure range is desirably configured to be exposed in a range corresponding to 50% or more and 100% or less of the total circumference L of the tube, preferably 60% or more, and more preferably 70%. % Or more will be advantageously employed. As described above, the brazing filler metal portion 18 is exposed over a predetermined area of the entire circumference L of the pipe on the outer peripheral surface of the flat multi-hole pipe 10, so that the aluminum brazing material contributing to brazing is stable. In particular, as shown in FIG. 1A, the brazing filler metal portion 18 is present over the entire circumference L of the pipe as the most preferable state. Is the case. If the exposed area is less than 50% of the circumferential length L of the pipe outer peripheral wall portion 14, there is a concern that defects such as unbonded fins or peeling off of the fins may occur during brazing heating. Further, it is not necessary to make all the thicknesses of the exposed regions of the brazing filler metal portion 18 in the entire circumference L of the pipe, for example, as shown in FIG. It is also possible to expose the material part 18. Further, it is desirable that such a brazing filler metal portion 18 is continuously exposed with respect to the entire circumference L of the pipe, but is also partially discontinuous or at a predetermined length. Even if it is exposed in a form extending in the pipe axis direction at a plurality of positions in the pipe circumferential direction, there is no problem.

Further, in the flat multi-hole tube 10 having such a structure, as is apparent from FIG. 1 (a), the entire circumference of the outer peripheral portion of the tube outer peripheral wall portion 14, at least a part of the flat portion (here, all The brazing filler metal portion 18 is exposed, while the brazing filler metal portion 18 is not exposed, that is, the flow including the internal partition wall portion 16 located between the

adjacent flow paths

12 and 12. A normal aluminum tube body material is present around the path 12. Here, the pipe outer peripheral wall portion 14 constitutes the outer peripheral wall of the flat multi-hole tube 10 as shown in the figure, and functions as an external partition for each flow path 12. When the brazing filler metal portion 18 formed on the pipe outer peripheral wall portion 14 is positioned on the pipe outer peripheral wall portion 14 as shown in FIG. 1B, the thickness Ta is determined by the pipe outer peripheral wall. It is present at a ratio of 90% or less, desirably 80% or less of the thickness Ts of the portion 14, and the lower limit thereof is preferably 1% or more, more preferably 5% or more. It will be. That is, Ta ≦ 0.9 × Ts, and Ta ≧ 0.01 × Ts is preferable. When the brazing filler metal portion 18 exceeds 90% of the thickness Ts of the pipe outer peripheral wall portion 14, the brazing filler metal portion 18 melts during brazing heating, and the thickness of the pipe outer peripheral wall portion 14 becomes too thin. This causes problems such as a decrease in pressure resistance as the flat multi-hole tube 10. In this way, by configuring the brazing filler metal portion 18 to be positioned on the outer surface side of the pipe outer peripheral wall portion 14, the aluminum brazing material is exposed and present on the outer surface of the pipe outer peripheral wall portion 14. As a result, the outer brazing performance can be advantageously exhibited.

In the flat multi-hole tube 10 according to 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 filler metal portion 18, but Si: 1.0 to 13.0 mass%, Mn: 1.4 mass% or less (excluding 0 mass%), Cr: 0.05 to 0.30 mass%, Zr: 0.05 to Containing at least one of 0.30% by mass, Ti: 0.05-0.30% by mass and Sr: 0.0001-0.1% by mass with the balance being aluminum and inevitable impurities (for example, Cu, An aluminum alloy such as Zn or Fe is used. Here, when the Si content exceeds 13.0% by mass, the melting point rapidly decreases, and there is a concern that the base material is melted during brazing heating. Moreover, if content of Si is less than 1.0 mass%, brazing property will fall. Also, if the Mn content exceeds 1.4% by mass, there is a problem that deformation resistance at the time of extrusion increases and high-speed extrusion becomes difficult, and further, a pickup phenomenon may occur at high-speed extrusion. Arise. Further, Cr, Zr, Ti, and Sr are alloy components that coarsen the crystal grain size after brazing and improve brazeability, and when their content is less than the range specified above, these alloys On the other hand, if the content of the alloy components is more than the above specified range, the generation of coarse compounds in the extruded material obtained by casting becomes remarkable, so the extrudability of the components becomes insufficient. Causes a problem that decreases. Note that the lower limit of Mn, which is an alloy component preferably contained in such an Al—Si based aluminum alloy, is generally about 0.1% by mass.

In addition, in the flat multi-hole tube 10 according to the present invention, as the aluminum tube main body material that is a material other than the aluminum brazing material that constitutes at least a part of the outer peripheral wall portion 14 of the tube, a flat multi-hole tube by extrusion has been conventionally used. Aluminum materials used in the manufacture of hole tubes can be used as they are, for example, JIS-named A1000 series pure aluminum materials, A3000 series aluminum alloy materials, etc. can be used as appropriate. In order to make the potential noble, it is also possible to contain a predetermined amount of Cu. Among them, as the material of such an aluminum tube main body material, Cu: 0.7% by mass or less (not including 0% by mass) and Mn: 1.4% by mass or less (not including 0% by mass) are advantageous. In addition, Cr: 0.05 to 0.30 mass%, Zr: 0.05 to 0.30 mass%, Ti: 0.05 to 0.30 mass%, and Sr: 0.0001 to 0 An aluminum alloy containing at least one of 1 mass% and the balance being aluminum and inevitable impurities (for example, Si, Fe, Zn, etc.) will be used. Here, if the Cu content exceeds 0.7% by mass, there is a problem that deformation resistance at the time of extrusion rises, making high-speed extrusion difficult, and pickup phenomenon occurs at high-speed extrusion. The fear of doing. Further, when the content of Mn exceeds 1.4% by mass, there is a problem that, as in the case of Cu, the deformation resistance at the time of extrusion rises, making high-speed extrusion difficult, and at the time of high-speed extrusion. There is a risk of pickup phenomenon. Further, Cr, Zr, Ti, and Sr are alloy components that coarsen the crystal grain size after brazing and improve brazeability, and when their content is less than the range specified above, these alloys On the other hand, if the content of the alloy components is more than the above specified range, the generation of coarse compounds in the extruded material obtained by casting becomes remarkable, so the extrudability of the components becomes insufficient. Causes a problem that decreases. Further, among these alloy components, generally 0.1% by mass is advantageously employed as the lower limit value of Cu, and 0.1% by mass is generally advantageously employed as the lower limit value of Mn. .

Furthermore, in the aluminum brazing material and the aluminum tube main body material constituting the flat multi-hole tube 10 described above, the remaining aluminum other than the alloy components described above, and naturally contained in the production of the material, Fe Among the inevitable impurities composed of various elements such as Zn, the total content of these inevitable impurities is regulated within a generally recognized range, and is usually 0.5% by mass or less, preferably 0.3% by mass. % Is controlled to be a ratio of less than or equal to%.

Then, the flat multi-hole tube 10 according to the present invention as described above is manufactured by using the above-described aluminum tube main body material and aluminum brazing material as an aluminum material to be extruded, and simultaneously extruding these materials. However, the pipe body material and the brazing material are generally used in combination of a composite billet having a core-sheath structure or a plurality of billets. Specifically, aluminum having a cross-sectional shape such as a circle, an oval, an ellipse, a rectangle, a half moon, a crescent, a polygon, etc. on the inner surface (center) of the aluminum brazing material, and an optimized cross-sectional dimension. A composite of a structure in which a sheath part made of the brazing material is formed around a core part made of the pipe body material by arranging the pipe body material, joining them by welding or the like, and integrating them. Billets are used.

For manufacturing such a composite billet, various known means can be appropriately adopted. For example, a sheath billet is formed by providing a through-hole of a predetermined size at the center of a billet made of an aluminum brazing material. In addition, the core billet made of an aluminum tube main body material is inserted into the through-hole, and the sheath billet is produced in the form of being divided into two parts. In the form in which the core billet is disposed in the space, the target composite billet can be formed by a method of fixing the whole by welding or the like and integrating them.

FIGS. 2A and 2B show an example of such a composite billet, in which the composite billet 20 is outside the cylindrical tube body material billet (core billet) 22. In addition, a cylindrical brazing material billet (sheath billet) 14 is integrally disposed.

Further, the composite billet 20 is applied with a technique of hot extrusion using a die having a plurality of extrusion ports, a so-called porthole die, similar to the case of manufacturing a conventional extruded flat multi-hole tube, As a result, the target extruded flat multi-hole tube 10 can be obtained. At this time, the longitudinal pusher disposed so as to correspond to the plurality of flow paths 12 of the flat multi-hole tube 10 is obtained. With respect to the die having an outlet, the composite body so that the longitudinal direction of the predetermined cross-sectional shape of the pipe body material (22) disposed inside the composite billet 20 coincides with the longitudinal direction of the extrusion port of the die. The billet 20 is arranged and hot extrusion is performed. By adopting such an extrusion form of the composite billet 20 by the port hole die, the brazing material (24) in the composite billet 20 can be effectively distributed to the flat outer peripheral portion of the obtained flat multi-hole tube 10. Thus, the brazing material portion can be advantageously exposed to the outer peripheral surface of the pipe.

By the way, when the composite billet 20 as described above is hot-extruded from the port hole die according to a conventional method to produce the target flat multi-hole tube 10, the billet 24 for the brazing material outside the composite billet 20 is provided. The brazing material portion 18 in the flat multi-hole tube 10 formed by being wound around the inner tube body material billet 22 easily enters the aluminum tube body material constituting the tube outer peripheral wall portion 14. In addition, during use as a heat exchanger, there is a risk that corrosion will occur at the part where the brazing filler metal part 18 enters and leakage of fluid will be caused.

Therefore, in the present invention, as shown in FIG. 2C, a predetermined disk-shaped front plate 26 is integrally disposed on the front end side (front side) of the composite billet 20 in the extrusion direction. In this case, a method of extruding from a port hole die is advantageously employed, and thereby, the entrainment of the brazing filler metal portion 18 at both end edges of the extruded flat multi-hole tube 10 to be formed can be effectively suppressed or prevented. It became.

That is, in such an extrusion process using the front plate 26, a circular or annular front plate 26 made of the same material as the aluminum tube main body material is fixed to the tip of the composite billet 20 by welding or the like. In this state, the diameter of the front plate 26 is in the range of 90% or more and 100% or less 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 billet 20, problems such as being caught when the composite billet 20 is inserted into the container and being unable to be extruded are caused. Further, when the diameter of the front plate 26 is smaller than 90% of the diameter of the composite billet 20, it exists in the metal of the billet 22 for aluminum tube body material located on the rear surface and the outer surface of the billet from the gap during the extrusion process. There is a risk that the oxide film, foreign matter, or the brazing material metal of the billet 24 for brazing material is pushed out preferentially, and the entanglement of both ends of the extruded flat multi-hole tube 10 may be defective. Furthermore, it is desirable that the thickness of the front plate 26 be 5% or more and 30% or less with respect to the diameter of the composite billet 20. Among these, a ratio of 10% or more and 25% or less is optimal. When the thickness of the front plate 26 is less than 5%, the range of dead metal remaining in the container cannot be sufficiently filled with the front plate material, and the brazing to both end edges of the extruded flat multi-hole tube 10 is not possible. If the thickness of the front plate 26 exceeds 30%, the material ratio of the front plate 26 becomes too high and the outer surface of the extruded flat multi-hole tube 10 may be damaged. There are problems such as an increase in the amount of product cut until the brazing material is stably clad.

In addition, the aluminum extrusion flat multi-hole pipe | tube according to this invention as mentioned above can be used suitably as a refrigerant | coolant flow path member in a heat exchanger. And when using the aluminum extrusion flat multi-hole pipe according to the present invention as a refrigerant passage pipe, for example, a pair of aluminum header tanks arranged at a distance from each other, and a width direction ventilation direction between both header tanks Facing each other, a plurality of extruded aluminum flat multi-hole pipes arranged in parallel with each other at intervals in the longitudinal direction of the header tank and having both ends connected to both header tanks, and adjacent flat multi-hole pipes Between and between the flat multi-hole pipes at both ends and brazed to these flat multi-hole pipes, and aluminum corrugated fins as outer fins, and arranged outside the corrugated fins at both ends, In a structure comprising an aluminum side plate brazed to such fins, a heat exchanger will be configured. Of course, in addition to the heat exchanger of such structures, as the refrigerant tube in the heat exchanger of various known, that can be used aluminum extruded flat multi-hole tube according to the present invention, it is needless to say place.

Further, as is well known, a pair of header tanks in a heat exchanger distributes and flows refrigerant or coolant from one header tank to a flat multi-hole tube, while the other header tank is flat flat. For collecting refrigerant or coolant that has flowed out of the hole tube, for example, as is known, the header plate and the header plate are brazed facing each other, or the plate is bent into a tubular shape and stacked. In addition to what is constructed by welding or brazing the combined ends, an extruded tube or the like extruded into a tubular shape will be used.

The exemplary embodiments of the present invention have been described in detail above, but these are merely examples, and the present invention is interpreted in a limited manner by specific descriptions according to such embodiments. It should be understood that it is not done.

And this invention can be implemented in the aspect which added various change, correction, improvement, etc. based on the knowledge of those skilled in the art, and such an aspect does not deviate from the meaning of this invention. Needless to say, all of them belong to the category of the present invention.

Hereinafter, representative examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is not limited by the description of such examples. That should also be understood.

First, as materials for manufacturing various flat multi-hole pipes, various billets A to R for aluminum brazing material having the component composition shown in Table 1 below and various aluminum pipes having the component composition shown in Table 3 below. After each billet a to o for main body material is cast, the various billets B1 to B32 shown in Table 5 below are manufactured by combining the billets in various combinations, and then the composite billets are respectively hot extruded. As a result, various flat multi-hole tubes T1 to T32 corresponding to the composite billets shown in Table 5 below were obtained. Similarly, after casting aluminum brazing material billets S to AA having the component composition shown in Table 2 below and various aluminum pipe body billets p to u having the component composition shown in Table 4 below, Various billets B33 to B52 and a single billet B53 shown in the following Table 6 are prepared by combining these billets in various ways, and then the composite billet and the single billet are respectively subjected to hot extrusion processing to obtain the following Table 6 Various flat multi-hole tubes T33 to T53 corresponding to those billets shown in FIG.

Thereafter, using the various flat multi-hole tubes T1 to T53 thus obtained, the following (1) evaluation of the presence or absence of entrainment failure of the brazing material layer, (2) measurement of the length of the defective cladding, (3) brazing material The measurement of the formation range of the part and (4) defect evaluation at the time of assembling the heat exchanger core were carried out.

Specifically, first, in order to form the brazing filler metal portion 18, 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 are provided. Each of the alloy components was adjusted, and various DC cast billets of 90 mmφ were prepared according to a conventional method. On the other hand, the alloy components were adjusted to give the aluminum tube body material billets a to o shown in Table 3 and the aluminum tube body material billets p to u shown in Table 4 to form the tube body part. Then, a DC cast billet was produced in the same manner as described above, and the obtained billet was molded into a cylindrical body having a predetermined dimension within a circular dimension of 5 mm to 85 mm.

Then, a through-hole into which the processed pipe body material billet can be inserted is formed in the central portion of the cross-section of the brazing material billet, and the pipe body material billet is inserted into the through-hole. The billet for the brazing material and the billet for the pipe body material are fixed and joined to each other in the longitudinal direction by MIG welding, and the composite billets B1 to B32 and B33 to B52 shown in Tables 5 and 6, respectively. Was made as an integral composite billet 20 having a cross-sectional configuration as shown in FIG. The extrusion billet B53 shown in Table 6 is a single billet shown as 30 in FIG. In FIGS. 2 and 3, 22 and 32 are pipe body material billets, and 24 is a brazing material billet.

Next, as shown in FIG. 2 (c) or FIG. 3 (c), various dimensions (diameter and thickness) shown in Tables 5 and 6 are formed on the front end surface in the extrusion direction of the obtained composite billet 20 or single billet 30. The disk-shaped front plate 26 is fixed by welding, and the billet-front plate assembly is heated to 500 ° C. with a billet heater. After heating, by hot extrusion from the front plate 26 side using a port hole die similar to the conventional one provided with an extrusion port for forming six rectangular holes (six flow paths) 6-flat multi-hole tubes T1 to T32 and T33 to T53 shown in Table 5 and Table 6 corresponding to each extrusion billet (total thickness: 2.0 mm, width in the flat direction: 16 mm, tube outer peripheral wall Thickness of partition and partition: 0.25 The m), were prepared, respectively. In addition, when producing the flat multi-hole tube T48 by hot extrusion using the composite billet B48, the billet caused clogging in the container, so the hot extrusion cannot proceed, and therefore I could not do it.

(1) Evaluation of troubles involving entrainment of brazing material layer Various flat multi-hole pipes (10) of 6 holes thus obtained were cut at a half position in the longitudinal direction of the extrusion, and the cross section was observed. That is, using a photograph of the cross-sectional microstructure taken at a magnification of 25x, the state of entrainment of the brazing filler metal part (18) is examined at both end edges of the flat multi-hole tube (10), and whether or not there is an entrainment defect. Was evaluated. And, when the brazing filler metal part (18) is not confirmed from any of both end edges (◯), when the brazing filler metal part (18) is confirmed even on one side of the pipe edge part, (×), evaluated.

Tables 7 and 8 below show the results of evaluation of the problem of entrainment of the brazing material portion (18) in the flat multi-hole tubes T1 to T32 and the flat multi-hole tubes T33 to T53, respectively. The flat multi-hole tube T48 was not evaluated because the hot extrusion process was stopped in the middle.

As a result of such cross-sectional observation, in the flat multi-hole pipes T1 to T32 obtained by the above-described extrusion process, no trouble in entrainment of the brazing filler metal part (18) at the pipe edge was confirmed.

On the other hand, flat multi-hole tubes T33, T34, and T53 obtained by carrying out hot extrusion using a port hole die using the composite billets B33, B34 and the single billet B53 do not contain any brazing filler metal component. Since the billet of the conventional alloy or pure Al alloy is used, there is no brazing material portion (18), and the trouble of the brazing material portion (18) being caught at both pipe end edges is not present. It was not confirmed. Similarly, in the flat multi-hole tubes T35 to T47, T50, and T52, the entrainment of the brazing filler metal portion (18) was not recognized. However, in the flat multi-hole pipes T49 and T51, it was confirmed that a trouble of entrainment of the brazing filler metal part (18) was caused at both end edges. In any case, the diameter or thickness of the used front plate is insufficient, and the surface of the pipe body billet located on the rear side in the extrusion direction, such as an oxide film or foreign matter, or a metal such as a brazing filler metal brazing material is used. It was recognized that the entrainment failure of the brazing filler metal part (18) occurred at both edge portions in the width direction of the flat multi-hole tube by flowing in preferentially.

(2) Measurement of length of defective cladding portion Using the flat multi-hole tubes T1 to T32 and T33 to T53 obtained above, the length of the defective cladding portion was measured. The flat multi-hole tubes T33, T34, and T53 do not use a billet containing a brazing filler metal component and are made of a conventional alloy or a pure Al alloy, so that the brazing filler metal portion (18) is formed. In addition, the flat multi-hole tube T48 was not evaluated because it could not be manufactured due to the suspension of hot extrusion.

Specifically, flat multi-hole tubes T1 to T32 and T33 to T53 are subjected to cross-sectional observation over the entire length at a pitch of 1.0 m in the extrusion direction after each hot extrusion process, and defective cladding The length of the part (only the front plate material, the one where the cladding rate is too large due to the influence of the front plate material) was measured. In the measurement of the length of the defective clad part, when the length of the defective clad part is 15 m or less, it is evaluated as (◯), and when the length is more than 15 m, it is evaluated as (x). 7 and Table 8.

As is clear from the results shown in Table 7, in each of the flat multi-hole tubes T1 to T32, the length of the defective cladding portion is 15 m or less, and the entrainment of the brazing material layer is effectively suppressed. It has been confirmed that

On the other hand, in the flat multi-hole tubes T33, T34, and T53, all are obtained using a billet that does not contain a brazing filler metal component. Even in the flat multi-hole tubes T35 to T47 and T52, although the defective cladding portion was confirmed, the length of the defective cladding portion was 15 m or less. However, in the flat multi-hole tubes T49 to T51, it has been confirmed that the length of the defective clad portion exceeds 15 m. In particular, the flat multi-hole tube T51 has a total length (about 60 m) to the extrusion tail portion where the extrusion is completed. A defective clad portion was confirmed.

(3) Measurement of formation range of brazing filler metal part Various 6-hole flat multi-hole pipes (10) obtained above were cut at a half position in the extrusion longitudinal direction, and the cross section was observed. That is, by using a photograph of the cross-sectional microstructure taken at a magnification of 25 times, the area of the brazing filler metal portion (18) was measured with a ruler, thereby measuring the formation range of the brazing filler metal portion (18). In the measurement of the forming range of the brazing filler metal part (18), when the forming range of the brazing filler metal part (18) is 100% or less and 50% or more of the pipe outer peripheral part circumferential length L (◯). When it was less than 50% of the circumference, it was evaluated as (x). Moreover, when the thickness of the brazing filler metal part (18) in the pipe outer peripheral wall part (14) is 90% or less of the thickness of the pipe outer peripheral wall part (14), (◯), when it exceeds 90% (× ) And evaluated.

Tables 9 and 10 below show the results of measuring the formation range of the brazing filler metal part (18) for the flat multi-hole tubes T1 to T32 and T33 to T53, and the brazing filler metal part exposed to the outer peripheral part of the pipe It is shown as the value at which the circumference of (18) is the minimum and the maximum thickness of the brazing filler metal part (18) in the pipe outer peripheral wall part (14).

As a result of the cross-sectional observation, the brazing material portion (18) made of the billet for the brazing material is included in the circumferential length L of the outer circumference of the tube in all of the circumferential length of the outer circumference of the flat multi-hole tubes T1 to T32 obtained by the extrusion process. It was confirmed that it was exposed at a ratio of 50% to 100%. Further, the thickness of the brazing filler metal part (18) formed on the pipe outer peripheral wall part (14) is present in a range of 90% or less of the thickness of the pipe outer peripheral wall part (14), It was observed that it was exposed on the outer surface of the tube. Furthermore, in the flat multi-hole tube (10) obtained by hot extrusion in this way, in the longitudinal direction of the extrusion, the brazing material portion (18) formed by the billet for brazing material is the outer peripheral portion of the tube. It was also confirmed that it was stably exposed on the outer surface.

On the other hand, flat multi-hole tubes T33, T34, and T53 obtained by carrying out hot extrusion with a port hole die using the composite billets B33, B34 and the single billet B53 do not contain a brazing filler metal component. Since a billet made of a conventional alloy or a pure Al-based alloy is used, there is no brazing filler metal part (18), and therefore no exposure on the outer surface of the pipe was observed. Further, in the flat multi-hole tube T51 obtained using the composite billet B51 shown in Table 6, the exposed portion of the brazing filler metal portion (18) is 100% of the tube outer peripheral portion circumferential length L, and the tube The thickness of the outer peripheral wall (14) was 93% at the thickest part. Furthermore, the flat multi-hole tubes T35 to T47, T49, T50, and T52 obtained by the above method using the composite billets B35 to B47, B49, B50, and B52 shown in Table 6 are used for the brazing filler metal portion (18). The exposed portions were all 50% or less of the tube outer peripheral portion circumferential length L, and the thickness of the tube outer peripheral wall portion (14) was 10 to 20% at the thickest portion. The flat multi-hole tube T48 was not evaluated because the billet was clogged during the hot extrusion of the composite billet B48 shown in Table 6 and the intended flat multi-hole tube was not obtained.

(4) Evaluation of defects during assembly of heat exchanger cores Using the flat multi-hole tubes T1 to T32 and T33 to T53 obtained above as the test materials, fins are assembled to each flat multi-hole tube and brazed and heated. This was carried out and evaluated for the occurrence of defects during the production of the heat exchanger core.

Specifically, bare fins with a thickness of 80 μm corrugated into a fin pitch of 3 mm and a fin height of 7 mm are assembled to the flat multi-hole tubes T1 to T32 and T33 to T53, respectively. Assuming brazing heating for fin bonding when used as a heat transfer tube in a heat exchanger, after heat treatment at 600 ° C. for 3 minutes and brazing to form a heat exchanger core The fins joined to the flat multi-hole pipes of the respective heat exchanger cores were cut and removed with a cutter, and the joining state of the fins and the fault occurrence state of the flat multi-hole pipes were visually confirmed.

In Tables 11 and 12 below, heat exchanger cores are manufactured using flat multi-hole tubes T1 to T32 and T33 to T53 as test materials, and the state of fin bonding of the heat exchanger core after brazing and the flat The results of verifying the status of occurrence of defects in the hole tube are shown respectively.

As is apparent from the results in Table 11, the flat multi-hole tubes T1 to T32 showed no defective fin bonding in the heat exchanger core after brazing heating and no defects in the flat multi-hole tube. Accordingly, it is recognized that the flat multi-hole tubes T1 to T32 all exhibit a good fin joint form due to the presence of the brazing material portion (18) and are good as a flat multi-hole tube for brazing. It was.

On the other hand, the flat multi-hole tubes T33, T34, and T53 shown in Table 12 are all flat multi-hole tubes using only a conventional material that does not contain a brazing filler metal component and a material made of a pure Al-based alloy. Therefore, the fins were not joined in the heat exchanger core after brazing heating. Further, even in the flat multi-hole tube T36, since the content of Si as the brazing material component was 0% by mass, the fins were not joined. Furthermore, since the flat multi-hole tube T35 shown in Table 12 has a Si content of 14.0% by mass and a large content, the brazing filler metal part (18) is not heated during brazing heating. It melted, and through holes due to melting were observed in the base material. In addition, it was recognized that the flat multi-hole tubes T37 to T47, T50, and T52 had a wide unjoined portion although some fins were joined. Furthermore, in the flat multi-hole tubes T49 and T51, the brazing filler metal layer (18) melts at the time of brazing heating in the poorly entrained portion of the brazing filler metal layer recognized at both end corners, and a through hole is formed. Admitted. In particular, in the flat multi-hole tube T51, the pipe outer peripheral wall portion (14) was melted in addition to the poorly wound portion of the brazing material layer at both ends of the flat multi-hole tube, and through holes due to melting were observed.

DESCRIPTION OF SYMBOLS 10 Flat multi-hole pipe 12 Flow path 14 Pipe outer peripheral wall part 16 Internal partition part 18 Brazing material part 20 Composite billet 22 Billet for pipe body material 24 Billet for brazing material 26 Front plate 30 Single body billet 32 Billet for pipe body material 34 Front board

Claims

An extruded tube having a flat cross-sectional shape as a whole obtained by extrusion of an aluminum material, and having a plurality of channels extending in parallel with each other in the tube axis direction, and these channels are An aluminum extruded flat multi-hole tube arranged in the longitudinal direction of a flat cross-sectional shape through an internal partition extending in the tube axis direction,
The aluminum material is formed by extrusion using an aluminum tube main body material and an aluminum brazing material made of an Al—Si based aluminum alloy, and the entire region of the outer peripheral wall of the tube or at least the outer peripheral wall of the tube The aluminum brazing material is exposed to a part of the flat part of the part to form a brazing material part, and the brazing material part is 50% of the circumference of the pipe outer peripheral wall part in the pipe cross section. As described above, the brazing filler metal portion located on the outer peripheral wall portion of the pipe is present at a ratio of 90% or less of the thickness of the outer peripheral wall portion of the pipe, while being present at a ratio of 100% or less. An aluminum extruded flat multi-hole tube with excellent brazing properties.
The aluminum brazing material contains Si: 1.0 to 13.0% by mass, Mn: 1.4% by mass or less, Cr: 0.05 to 0.30% by mass, Zr: 0.05 to One or more of 0.30% by mass, Ti: 0.05-0.30% by mass and Sr: 0.0001-0.1% by mass, with the balance being aluminum and inevitable impurities On the other hand, the aluminum tube main body material contains Cu: 0.7% by mass or less and Mn: 1.4% by mass or less, and Cr: 0.05-0.30% by mass, Zr. : 0.05 to 0.30% by mass, Ti: 0.05 to 0.30% by mass, and Sr: 0.0001 to 0.1% by mass or more, and the balance being aluminum And an aluminum alloy that is an inevitable impurity Excellent aluminum extruded flat multi-hole tubes having brazeability according to claim 1, wherein.
The aluminum extruded flat multi-hole tube having excellent brazing properties according to claim 1 or 2, wherein the aluminum material to be extruded is a composite billet composed of the aluminum tube main body material and the aluminum brazing material. .
4. The composite billet has an integral core-sheath structure comprising a core billet made of the aluminum tube main body material and a sheath billet made of the aluminum brazing material located around the core billet. An aluminum extruded flat multi-hole tube having excellent brazing properties described in 1.
The aluminum extruded flat multi-hole tube having excellent brazing properties according to any one of claims 1 to 4, wherein the extruded tube is formed by extruding the aluminum material using a porthole die.
A method for producing an aluminum extruded flat multi-hole tube according to any one of claims 1 to 5,
A composite billet composed of an aluminum tube main body material and an aluminum brazing material made of an Al—Si based aluminum alloy is used, and a front plate made of the same material as the aluminum pipe main body material is used. 90% or more and 100% or less with respect to the diameter of the front plate, and the thickness of the front plate is set to be 5% or more and 30% or less with respect to the diameter of the composite billet. A method for producing an aluminum extruded flat multi-hole tube having excellent brazing properties, characterized in that the composite billet is disposed on the front side in the extrusion direction and the front plate and the composite billet are extruded together with a port hole die.
7. The composite billet has an integral core-sheath structure comprising a core billet made of the aluminum tube main body material and a sheath billet made of the aluminum brazing material located around the core billet. A method for producing an aluminum extruded flat multi-hole tube having excellent brazing properties as described in 1.
It is comprised including the aluminum extrusion flat multi-hole pipe of any one of Claim 1 thru | or 5, and the aluminum outer fin brazed and joined to the outer surface of this aluminum extrusion flat multi-hole pipe. An aluminum heat exchanger characterized by that.