WO2018147375A1 - Aluminum extruded flat perforated pipe exhibiting excellent brazing properties and outer-surface corrosion resistance, and aluminum heat exchanger obtained using same - Google Patents

Abstract

The present invention provides an aluminum extruded flat perforated pipe exhibiting excellent brazing properties and outer-surface corrosion resistance in the pipe outer-circumferential section thereof. An aluminum extruded flat perforated pipe 10 formed by simultaneously extruding an aluminum pipe main body material and a more electrochemically basic sacrificial anode/brazing material comprising an Al-Si-Zn-based aluminum alloy, wherein a sacrificial anode/brazing material section 18 is formed by exposing the sacrificial anode/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 excellent in brazing and outer surface anticorrosion properties, and aluminum heat exchanger using the same

TECHNICAL FIELD The present invention relates to an aluminum extruded flat multi-hole tube excellent in brazing properties and outer surface anticorrosion properties and an aluminum heat exchanger using the same, and more particularly, a heat exchanger, particularly a heat exchanger for an automobile such as a car air conditioner. Aluminum extruded flat multi-hole tube for heat exchangers with excellent outer surface anticorrosion properties while using a brazing material component on the outer surface of the tube to which the fins are brazed and joined. It is related with the aluminum heat exchanger obtained by this.

Conventionally, extruded flat multi-hole pipes with a flat cross-sectional shape as a whole obtained by extrusion processing of aluminum materials have been used as refrigerant passage pipes in automotive heat exchangers, and refrigerant flows through the refrigerant passages. On the other hand, a heat exchanger is constructed by assembling and brazing aluminum fins clad with an aluminum brazing material in a direction perpendicular to the refrigerant passage tube, and heat is produced along the fins. By flowing air as an exchange fluid, heat exchange is performed between the refrigerant and the air.

As such an extruded flat multi-hole tube, one obtained by extruding a billet of aluminum or aluminum alloy is usually used. For example, JP-A-6-142755 (Patent Document 1). JP-A-5-222480 (Patent Document 2), WO2013 / 125625 (Patent Document 3) and the like have revealed a flat multi-hole tube having a cross-sectional shape.

By the way, in the flat multi-hole tube obtained by extrusion processing used as a heat transfer tube of such a heat exchanger, as described above, to braze and join the fin for heat exchange to the outer surface However, it is necessary to use brazing fins clad with brazing material. However, the outer surface of the flat multi-hole tube is not subjected to anticorrosion treatment, so there is a problem that corrosion is caused. is doing. And if the corrosion hole etc. which penetrate a pipe wall arise by the progress of such corrosion, the function as a heat exchanger will be lost at all. That is, when penetration due to corrosion occurs during use of such a refrigerant passage tube, refrigerant leakage occurs, and the function as a heat exchanger cannot be achieved.

Therefore, in such a heat exchanger, in order to prevent corrosion of the outer surface of the extruded flat multi-hole tube, conventionally, Zn is adhered to the surface of the extruded flat multi-hole tube in advance by a method such as spraying or painting. The Zn diffusion layer formed on the tube surface layer acts as a sacrificial anode for the tube layer deeper than the Zn diffusion layer by brazing heating, and corrodes in the tube thickness direction. Is suppressed, and the penetrating life of the tube is extended. In this case, the extruded flat multi-hole tube requires a Zn adhesion process such as spraying and coating of Zn after being extruded, and then a fluoride-based flux coating process necessary for brazing or heat. Since a flux coating process is required for the entire core after being assembled to the exchanger core, there is a problem that causes an increase in manufacturing cost. Further, since the extruded flat multi-hole tube is not provided with a brazing material, brazing fins clad with the brazing material are required for the fin material to be assembled. This also leads to an increase in cost compared to the case of using a bare fin material in which the brazing material is not clad.

Therefore, as one of the above-described extruded flat multi-hole tubes, an aluminum alloy having a specific component composition is used singly as disclosed in the above-mentioned JP-A-5-222480 (Patent Document 2). Thus, it has been proposed to produce a flat multi-hole tube having an appropriate anti-corrosion property by extrusion, but the flat multi-hole tube itself does not have brazing properties and has an outer surface. Not only is the anti-corrosion property sufficient, but it can not only fully meet the recent demands for high anti-corrosion properties and cost reduction, but also the tube obtained from the fact that the entire tube is made of a specific aluminum alloy. There is also a problem that the characteristics are limited by an aluminum alloy having such a specific alloy composition.

In JP-A-63-97309 (Patent Document 4), 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 used simultaneously. There has been proposed a method of manufacturing a clad tube in which a brazing filler metal layer is clad on the outer surface flat portion of the tube peripheral wall by extrusion, but such a clad tube has no sacrificial anode effect. The outer surface did not have anticorrosive properties.

JP-A-6-142755 JP-A-5-222480 WO2013 / 125625 JP-A-63-97309

Under such circumstances, the inventors of the present invention have made extensive studies in order to advantageously improve the brazing property and outer surface corrosion resistance of the outer periphery of the aluminum extruded flat multi-hole tube obtained by extrusion processing of an aluminum material. Aluminum extrusion obtained by simultaneously performing hot extrusion using a normal aluminum tube body material and a predetermined sacrificial anode / brazing material made of an Al—Si—Zn-based aluminum alloy as the aluminum material to be processed A sacrificial anode / brazing material portion made of such an Al—Si—Zn-based aluminum alloy can be advantageously exposed on the outer periphery of the flat multi-hole tube to form a sacrificial anode / brazing material portion, and Due to the presence of the sacrificial anode / brazing material part, effective brazing properties can be obtained, and the sacrificial anode effect that can be exhibited makes aluminum It was found that may also impart excellent outer surface corrosion resistance to the tube outer periphery of the flat multi-hole tubes out.

Therefore, the present invention has been completed based on such knowledge, and the problem to be solved is an aluminum extrusion flattened shape which is obtained by extrusion processing of an aluminum material and exhibits a flat cross-sectional shape as a whole. The object of the present invention is to provide an aluminum extruded flat multi-hole tube that effectively imparts excellent brazing properties and excellent outer surface anticorrosive properties at the outer periphery of the multi-hole tube. An object of the present invention is to provide a useful aluminum heat exchanger obtained by using the heat exchanger.

In the present invention, in order to solve the problems as described above, an extruded tube having an overall flat cross-sectional shape obtained by extrusion processing of an aluminum material, the tube shafts independently of each other. An aluminum extruded flat multi-hole pipe having a plurality of flow paths extending in parallel to the direction and arranged in the longitudinal direction of a flat cross-sectional shape, and the aluminum material as the aluminum material And a sacrificial anode / brazing material made of an Al—Si—Zn-based aluminum alloy that is electrochemically less basic than the aluminum tube body material, and the outer peripheral wall portion of the tube The sacrificial anode / brazing material is exposed to the entire region or at least a part of the flat portion of the outer peripheral wall of the tube to form a sacrificial anode / brazing material portion. The aluminum extruded flat multi-hole tube having excellent brazing properties and the outer surface corrosion resistance, characterized the door, it is to its gist.

According to one of the preferred embodiments of the aluminum extruded flat multi-hole tube excellent in brazing property and outer surface anticorrosion property according to the present invention, the sacrificial anode / brazing material contains Si: 1.0 to 13.0 mass. % And Zn: 0.1 to 7.0% by mass, with the balance being aluminum and an aluminum alloy that is an inevitable impurity, while the aluminum tube body material is Cu: 0.7% by mass or less and Mn: 1.4% by mass or less, and the balance is made of aluminum and an aluminum alloy that is an inevitable impurity.

Moreover, according to one of the desirable embodiments of the aluminum extruded flat multi-hole tube according to the present invention, the aluminum alloy constituting the sacrificial anode / brazing material further contains Mn: 1.4 mass% or less, Cr: 0.05 One or two of ˜0.30 mass%, Zr: 0.05 to 0.30 mass%, Ti: 0.05 to 0.30 mass%, and Sr: 0.0001 to 0.1 mass% Contains the above.

Furthermore, according to another desirable aspect of the present invention, the aluminum alloy constituting the aluminum tube main body material further contains Cr: 0.05 to 0.30 mass%, Zr: 0.05 to 0.30 mass%. , Ti: 0.05 to 0.30% by mass and Sr: 0.0001 to 0.1% by mass or more.

In addition, in one of the advantageous embodiments of the aluminum extruded flat multi-hole tube according to the present invention, the sacrificial anode / brazing material portion located on the outer peripheral wall portion of the tube has a thickness of the outer peripheral wall portion of the tube. It is made to exist in the ratio below%.

Further, in the aluminum extruded flat multi-hole tube according to the present invention, advantageously, the sacrificial anode / brazing material portion is 50% or more and 100% or less of the circumference of the tube outer peripheral wall portion in the tube cross section. It is configured to exist in proportion.

Furthermore, in another desirable aspect of the aluminum extruded flat multi-hole tube according to the present invention, the potential difference between the sacrificial anode / brazing material and the aluminum tube body material is 5 mV or more and 300 mV or less. preferable.

Furthermore, in another preferable aspect of the aluminum extruded flat multi-hole tube according to the present invention, the extruded aluminum material is composed of the aluminum tube main body material and the sacrificial anode / brazing material. A composite billet will be used.

In addition, in another preferred embodiment of the present invention, the composite billet is composed of a core billet made of the aluminum tube main body material and the sacrificial anode / brazing material located around the core billet. It has an integral core-sheath structure composed of a sheath billet.

In the aluminum extruded flat multi-hole tube according to the present invention, the extruded tube is generally formed by extrusion processing of the aluminum material using a port hole die.

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, the Al—Si—Zn-based aluminum alloy is formed over the entire outer periphery of the tube, or at least a part of the flat portion of the outer periphery of the tube. Since the sacrificial anode / brazing material portion composed of the sacrificial anode / brazing material is exposed and made to exist, it exhibits excellent brazing properties, and by the sacrificial anode effect of the sacrificial anode / brazing material, The outer surface anticorrosion can be effectively enhanced, and as a result, it is advantageously used as a heat exchanger tube for heat exchangers such as radiators and heaters, which have excellent brazing and outer surface anticorrosion properties on the tube outer surface side. It was to get.

Moreover, the aluminum extruded flat multi-hole tube according to the present invention is composed of an aluminum tube main body material and a sacrificial anode / brazing material made of an Al—Si—Zn-based aluminum alloy, and is formed by simultaneous extrusion of these two materials. Therefore, the characteristics as a tube are ensured by the aluminum tube body material, while the brazing property and the external corrosion resistance are effectively exhibited by such a specific sacrificial anode / brazing material. Thus, the design flexibility of the target extruded flat multi-hole tube can be advantageously increased.

Furthermore, in an aluminum heat exchanger constituted by assembling an aluminum extruded flat multi-hole tube according to the present invention and an aluminum outer fin and joining them by brazing heating, the aluminum extruded flat multi-hole The excellent anticorrosive properties of the outer surface of the tube can also advantageously increase the anticorrosion properties as a heat exchanger.

It is sectional explanatory drawing which shows typically an example of the aluminum extrusion flat multi-hole pipe | tube according to this invention, Comprising: (a) shows the whole figure, (b) expands a part of the width direction center part. (C) is an explanatory view showing, in an enlarged manner, a part of the end portion in the width direction of an example in which the sacrificial anode / brazing material portion is present in the pipe outer peripheral wall portion at different thicknesses. . It is explanatory drawing which shows the cross section of the composite billet used in the Example. It is explanatory drawing which shows the cross section of the single billet used in the Example.

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. Further, the corresponding upper surface and lower surface of the flat multi-hole tube 10 are respectively flat surfaces, and outer fins (not shown) such as plate fins and corrugated fins can be described later, as in the prior art. In addition, it can be used as a heat exchanger by being attached by a brazing joint technique. 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 various shapes. is there.

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 a normal aluminum tube body material is present around the flow path 12 including the portion 16, a flat surface that provides at least the flat surface in the tube outer peripheral wall portion 14 of the entire circumference of the tube outer peripheral wall portion 14. A sacrificial anode / brazing material portion 18 composed of a sacrificial anode / brazing material made of an Al—Si—Zn-based aluminum alloy is present in a part of the portion, and the sacrificial anode / brazing material portion 18 is formed into a tube. At least a part of the outer surface of the outer peripheral wall portion 14 (here, the entire outer peripheral surface) is exposed. Further, as shown in FIG. 1A, the sacrificial anode / brazing material portion 18 is preferably 50% or more, more preferably 60%, of the circumferential length L of the pipe outer peripheral wall portion 14. %, More preferably 70% or more, and 100% or less. If the sacrificial anode / brazing material portion 18 is present in an area of less than 50% of the circumferential length L of the tube 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. The Thus, by arranging the sacrificial anode / brazing material portion 18 so as to be exposed on the surface of the pipe outer peripheral wall portion 14, an effective brazing property can be obtained by the brazing material component of the sacrificial anode / brazing material, and sacrificing. By the sacrificial anode effect due to the sacrificial anode component contained in the anode / brazing material, corrosion proceeds preferentially in the sacrificial anode / brazing material portion 18, so that materials other than the sacrificial anode / brazing material portion are effective. Thus, the effect of suppressing or preventing the generation of through-holes that cause coolant leakage at an early stage due to corrosion is advantageously exhibited.

Further, as shown in FIG. 1B, the sacrificial anode / brazing material portion 18 located on the tube outer peripheral wall portion 14 has a thickness Ta of 90% or less of the thickness Ts of the tube outer peripheral wall portion 14. It is preferably configured as described above, and particularly desirably, it is allowed to be present at a ratio of 80% or less, and the lower limit thereof is preferably 1% or more, more preferably 5% or more, It will be made to exist. That is, Ta ≦ 0.9 × Ts, and Ta ≧ 0.01 × Ts is preferable. When the thickness Ta of the sacrificial anode / brazing material portion 18 exceeds 90% of the thickness Ts of the outer peripheral wall portion 14 of the pipe, the corrosion of the sacrificial anode / brazing material portion 18 is reduced. As the thickness becomes too thin, the pressure resistance strength of the flat multi-hole tube 10 is reduced, or when the sacrificial anode / brazing material portion 18 is melted during brazing, a through-hole is generated in the outer peripheral wall portion 14. To come up with.

Further, the sacrificial anode / brazing material portion 18 is exposed on the outer surface of the outer peripheral wall portion 14 of the flat multi-hole tube 10 as shown in FIG. 18 is desirably continuously exposed over the entire circumference of the pipe on the outer surface of the pipe outer peripheral wall portion 14, but the exposure ratio in the circumferential direction of the sacrificial anode / brazing material portion 18 in the pipe axis direction. May be different from each other, partially discontinuous in the pipe circumferential direction or the pipe axis direction, or exposed in a form extending in the pipe axis direction at a plurality of positions in the pipe outer circumference direction at a predetermined length. There is no problem. In the present invention, advantageously, such a sacrificial anode / brazing material portion 18 is always exposed to the outer surface of the tube outer peripheral wall portion 14 in an arbitrary cross section of the flat multi-hole tube 10. Will be adopted.

As described above, the sacrificial anode / brazing material portion 18 is exposed over at least 50% or more of the peripheral length L of the tube outer peripheral wall portion 14, so that the brazing property and the anticorrosive property due to the sacrificial anode effect are exhibited. In particular, in the most preferable state, as shown in FIG. 1A, the sacrificial anode / brazing material portion 18 has a circumferential length L of the tube outer peripheral wall portion 14. It exists when it exists over the full length. It is not necessary for the sacrificial anode / brazing material portion 18 exposed on the outer surface of the tube to have the same thickness in the tube circumferential direction. For example, as shown in FIG. It is also possible for the sacrificial anode / brazing material portion 18 to be present at different thickness ratios.

In the flat multi-hole tube 10 according to the present invention, an Al—Si—Zn-based aluminum alloy is advantageously used as the material of the sacrificial anode / brazing material constituting the sacrificial anode / brazing material portion 18. In this case, an aluminum alloy containing Si: 1.0 to 13.0 mass% and Zn: 0.1 to 7.0 mass% with the balance being aluminum and inevitable impurities is used. Here, Si is a brazing filler metal component, and when its content exceeds 13.0% by mass, the melting point rapidly decreases, and there is a concern that the base metal is melted during brazing heating. Moreover, when Si content becomes less than 1.0 mass%, the problem that brazing property falls will be raised. Furthermore, Zn is a sacrificial anode material component, and if its content exceeds 7.0% by mass, the melting point decreases, and there is a concern that the base material is melted during brazing heating, while the Zn content If the amount is less than 0.1% by mass, it is difficult to sufficiently exhibit the sacrificial anode effect.

In the Al—Si—Zn-based aluminum alloy as described above, Mn: 1.4% by mass or less (not including 0% by mass), Cr: 0.05 to 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 one or more of them may be contained. It will be. Here, if the content of Mn 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 a pickup phenomenon may occur at high-speed extrusion. Occurs. In addition, 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, On the other hand, when the content of these alloy components is more than the above specified range, the generation of coarse compounds in the extrusion material obtained by casting becomes remarkable. This causes problems such as deterioration of the extrudability. Note that the lower limit of Mn, which is an alloy component suitably contained in such an Al—Si—Zn-based aluminum alloy, is generally about 0.1% by mass.

Further, in such a flat multi-hole tube 10, an aluminum tube main body material which is a material other than the sacrificial anode / brazing material that is exposed by constituting at least a part of the outer peripheral wall portion 14 of the tube is conventionally extruded. Aluminum materials used in the manufacture of flat multi-hole pipes can be used as they are, for example, JIS-named A1000 series pure aluminum materials, A3000 series aluminum alloy materials, etc. can be used. In order to make the potential noble, it is 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. ), And the balance is aluminum and an aluminum alloy with inevitable impurities. 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. Furthermore, when 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 a pickup phenomenon may occur at high-speed extrusion. 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. .

Further, such an aluminum alloy for a pipe body material containing Cu and Mn also contains Cr: 0.05 to 0.30 mass%, Zr: 0.05 to 0.30 mass%, Ti: 0 It is desirable that one or two or more of 0.05 to 0.30% by mass and Sr: 0.0001 to 0.1% by mass are contained. Here, the added Cr, Zr, Ti, and Sr are alloy components that coarsen the crystal grain size after brazing and improve the brazing property, respectively, and their contents are defined above. When the content is less than the range, the effect of adding these alloy components becomes insufficient. On the other hand, when the content of the alloy components exceeds the specified range, generation of coarse compounds in the extrusion material obtained by casting is remarkable. Therefore, problems such as a decrease in extrudability are caused.

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

By the way, the sacrificial anode / brazing material used in the present invention is electrochemically lower than the aluminum tube body material. Therefore, the potential difference between these materials exceeds 0 mV, but is preferably in the range of 5 mV to 300 mV. When this potential difference is 5 mV or more, the sacrificial anode effect is surely easily exhibited even in a more severe corrosive environment. On the other hand, when the potential difference exceeds 300 mV, the sacrificial anode effect becomes prominent, and problems such as severe corrosion consumption of the sacrificial anode / brazing material are caused. As described above, since the sacrificial anode / brazing material portion 18 is lower in potential than the internal partition wall portion 16 made of the aluminum tube main body material, the peripheral wall portion of the flow path 12, and the like, an effective sacrificial anode effect can be exhibited. Thus, the corrosion resistance of the outer peripheral surface of the pipe can be expressed more advantageously.

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 the sacrificial anode / brazing material as the aluminum material to be extruded, and simultaneously extruding these materials. However, the aluminum tube main body material and the sacrificial anode / brazing material are generally used in combination of a composite billet having a core-sheath structure or a plurality of billets. Specifically, the billet made of the sacrificial anode / brazing material has a cross-sectional shape such as a circular shape, an oval shape, an elliptical shape, a rectangular shape, a half-moon shape, a crescent shape, or a polygon shape, and a cross-sectional dimension. By placing billets made of optimized aluminum tube body material, joining them together by welding or the like, and integrating them, the sacrificial anode / brazing material billet around the core portion made of aluminum tube body material billet A composite billet having a structure in which a sheath portion made of is formed is used. In this composite billet, various known means can be employed, for example, a sheath billet is formed by providing a through-hole of a predetermined size at the center of a billet made of a sacrificial anode / wax material, and In addition to a method in which a core billet made of an aluminum tube main body material is inserted into the through-hole and integrated, the sheath billet is produced in the form of being divided into two, and in the space of the split sheath billet, In the form in which the core billet is arranged, the target composite billet can be formed by a method of fixing the whole by welding or the like and integrating them.

Furthermore, a hot extruding technique is applied to such a composite billet using a die having a plurality of extrusion ports, a so-called port hole die, as in the case of manufacturing a conventional extruded flat multi-hole tube. Thus, the target extruded flat multi-hole tube can be obtained. At that time, a die having a long extrusion port arranged to correspond to a plurality of flow paths of the flat multi-hole tube In contrast, the composite billet is disposed so that the longitudinal direction of the predetermined cross-sectional shape of the aluminum tube main body material disposed inside the composite billet coincides with the longitudinal direction of the extrusion port of the die. Inter-extrusion is performed. By adopting the extrusion form for the port hole die of such a composite billet, the sacrificial anode and the brazing material in the composite billet can be effectively distributed to the flat outer periphery of the obtained flat multi-hole tube. -The brazing material portion can be advantageously exposed to the outer peripheral surface of the pipe.

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, it can be used an aluminum extruded flat multi-hole tube according the present invention is of course 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 U for the sacrificial anode and brazing material having the component compositions shown in Table 1 below and various components having the component compositions shown in Table 3 below. After billets a to q for aluminum tube main body were cast, various billets B1 to B37 shown in Table 5 below were prepared by various combinations of these billets, and then the composite billets were respectively hot extruded. By processing, various flat multi-hole tubes T1 to T37 corresponding to these composite billets shown in Table 5 below were obtained. Similarly, various sacrificial anode / brazing material billets V to AF having the component compositions shown in Table 2 below and various aluminum tube main body billets r to w having the component compositions shown in Table 4 below are cast. Then, various billets B38 to B54 and a single billet B55 shown in Table 6 below are prepared by combining these billets in various combinations, and then the composite billet and the single billet are respectively subjected to hot extrusion. As shown in Table 6 below, various flat multi-hole tubes T38 to T55 corresponding to these billets were obtained.

Thereafter, using the various flat multi-hole tubes T1 to T55 thus obtained, the following (1) measurement of the formation range of the sacrificial anode / brazing material part, (2) potential measurement, (3) evaluation of anticorrosion on the outer surface, And (4) The defect evaluation at the time of core preparation was implemented, respectively.

Specifically, for the formation of the sacrificial anode / brazing material portion 18, first, the sacrificial anode / brazing material billets A to U shown in Table 1 and the sacrificial anode / brazing material billet V shown in Table 2 are used. Each of the alloy components was adjusted so as to give .about.AF, and various DC cast billets of 90 mm.phi. Were prepared according to a conventional method. On the other hand, in order to form the tube body part, the alloy components were adjusted to give the tube body material billets a to q shown in Table 3 and the tube body material billets r to w shown in Table 4, A billet produced in the same manner as described above was molded and processed 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 center of the cross section of the sacrificial anode / wax material billet, and the pipe body material billet is inserted into the through hole. Further, the billet for the sacrificial anode / brazing material and the billet for the tube body material are fixed and joined to each other in the longitudinal direction by MIG welding, and each of the extrusion (composite) billets B1 shown in Table 5 is used. ~ B37 were fabricated as an integral composite billet 20 having a cross-sectional configuration as shown in FIG. In the same manner, extrusion billets B38 to B54 and B55 each consisting of the billet combinations shown in Table 6 were produced.

The extrusion billet B55 is a single billet shown as 30 in FIG. 2 and 3, reference numerals 22 and 32 are billets for tube main body materials, and reference numeral 24 is a billet for sacrificial anode and brazing material.

Subsequently, the composite billet 20 or the single billet 30 thus obtained was heated to 500 ° C. with a billet heater and then provided with an extrusion port for forming eight rectangular holes (eight flow paths). Are subjected to hot extrusion using the same porthole dies as shown in Table 5 and Table 6 and 8-hole flat multi-hole tubes T1 to T37 and T38 to T55 (total thickness: 2.0 mm, flat direction) , The thickness of the outer peripheral wall portion of the pipe and the wall thickness of the inner partition wall portion: 0.25 mm).

(1) Measurement of formation range of sacrificial anode / brazing material portion Various flat multi-hole pipes (10) thus obtained were cut at a half position in the longitudinal direction of the extrusion, and the cross section was observed. . That is, the sacrificial anode / brazing material part (18) is formed by measuring the area of the sacrificial anode / brazing material part (18) with a ruler using a photograph of the cross-sectional microstructure taken at a magnification of 25 times. Range was measured. In the measurement of the formation range of the sacrificial anode / brazing material portion (18), the formation range of the sacrificial anode / brazing material portion (18) is 50% or less of the circumference L of the outer peripheral wall portion of the pipe. When it was above, it was evaluated as (◯), and when it was less than 50% of the tube outer peripheral wall circumferential length L, it was evaluated as (×). Further, when the thickness of the sacrificial anode / brazing material portion (18) in the outer peripheral wall portion (14) is 90% or less of the thickness of the outer peripheral wall portion (14) (◯), when the thickness exceeds 90% Evaluation was made as (×).

Tables 7 and 8 below show the results of measuring the formation range of the sacrificial anode / brazing material portion (18) for the flat multi-hole tubes T1 to T37 and the flat multi-hole tubes T38 to T55. As the value at which the circumference of the sacrificial anode / brazing material portion (18) exposed to the portion becomes the minimum, the maximum thickness of the sacrificial anode / brazing material portion (18) in the outer peripheral wall portion (14) is shown. .

As a result of the cross-sectional observation, the sacrificial anode / brazing material portion (18) comprising the sacrificial anode / brazing material billet is formed on all the outer peripheral wall lengths of the flat multi-hole tubes T1 to T37 obtained by the extrusion process. It was confirmed that was exposed at a ratio of 50% or more and 100% or less of the circumference of the pipe outer peripheral wall. Further, the thickness of the sacrificial anode / brazing material portion (18) formed on the outer peripheral wall portion (14) is in a range of 90% or less of the thickness of the outer peripheral wall portion (14). It was confirmed that the sacrificial anode / brazing material part (18) was exposed.

Further, in the flat multi-hole tube (10) obtained by hot extrusion in this way, in the longitudinal direction of extrusion, the sacrificial anode / brazing material portion (18) formed by the sacrificial anode / brazing material billet. ) Was also stably exposed on the outer surface of the pipe outer peripheral wall.

On the other hand, flat multi-hole tubes T38, T39, and T55 obtained by hot extrusion using a port hole die using composite billets B38 and B39 and a single billet B55 have sufficient contents of Si and Zn. Since no billet or billet for the sacrificial anode / brazing material is used and the billet is made of a conventional alloy, there was no exposed portion of the sacrificial anode / brazing material portion (18). Further, the flat multi-hole tube T40 obtained by the above method using the composite billet B40 shown in Table 6 is such that the exposed portion of the sacrificial anode / brazing material portion (18) is 100% of the peripheral length of the outer peripheral wall portion of the tube. The thickness of the outer peripheral wall portion (14) was 93% at the thickest part. Further, the flat multi-hole tubes T41 to T54 obtained by the above method using the composite billets B41 to B54 shown in Table 6 are all exposed parts of the sacrificial anode / brazing material part (18). The wall peripheral length L was less than 50%, and the thickness of the pipe outer peripheral wall (14) was 10 to 20% at the thickest part.

(2) Potential measurement Using the flat multi-hole tubes T1 to T37 and flat multi-hole tubes T38 to T55 obtained above, the potentials of the tube body material and the sacrificial anode / brazing material were measured. The flat multi-hole tubes T38, T39 and T55 basically use no sacrificial anode / brazing material billet, and are a conventional alloy and a pure Al alloy, so the sacrificial anode / brazing material portion (18) is Not formed.

Specifically, brazing heating for fin bonding when the flat multi-hole tubes T1 to T37 and flat multi-hole tubes T38 to T55 are used as heat transfer tubes in a heat exchanger is assumed. Then, after heat treatment at 600 ° C. for 3 minutes, they were cut in a length of 40 mm in the longitudinal direction of extrusion. In this heat treatment, since melting was observed in the flat multi-hole tube T40, subsequent evaluation could not be performed. Next, the test material for measuring the potential of the tube body material is for measuring the potential on one side of the cut end surface while leaving the exposed surface of the tube body material of 10 mm × 10 mm at the center in the width direction of the inner surface on one side of the peripheral wall. All the parts except for the part connecting the lead wires were masked with silicone resin to be electrically insulated. In addition, the test material for measuring the potential of the sacrificial anode / brazing material part (18) (sacrificial anode material) is a sacrificial anode / brazing material part (10 mm × 10 mm) at the center in the width direction of the flat outer flat part. 18) Except for the exposed surface of 18), all of the cut end surface except for the portion where the lead wire for potential measurement was connected was masked with silicone resin to be electrically insulated.

As a method for measuring the potential, a saturated KCl calomel electrode (SCE) is used as a reference electrode, while a 5% NaCl aqueous solution adjusted to pH 3 with acetic acid is used as a test solution. A method of measuring each potential after immersing the test material in the solution for 24 hours while stirring at room temperature was employed.

The results of the potential difference between the tube body material obtained by the above measurement and the sacrificial anode / brazing material are shown in Tables 9 and 10 below. When the potential difference between the tube body material and the sacrificial anode / brazing material is 5 mV or more and 300 mV or less (（), when the potential difference exceeds 0 mV and less than 5 mV, or exceeds 300 mV (◯), In the case of 0 mV, it evaluated as (x).

As is clear from the potential measurement results shown in Table 9, in the flat multi-hole tubes T1 to T37, the potential difference between the sacrificial anode / brazing material portion (18) and the tube main body material after the brazing heating is assumed as follows. 5 to 290 mV, all showing results having an effective sacrificial anode effect.

On the other hand, as shown in Table 10, when the flat multi-hole tubes T38 to T55 are used as test materials, the flat multi-hole tubes T38, T39 and T55 are basically composed of sacrificial anode and brazing material. Therefore, the potential difference was 0 mV because it was a flat multi-hole tube substantially composed only of the same tube body material as the conventional material.

Further, when the same potential measurement as described above was performed using the flat multi-hole tube T43 as a test material, the sacrificial anode / brazing material portion (18) of the flat multi-hole tube T43 contained 8% by mass of Zn. As a result, the potential difference between the sacrificial anode / brazing material portion (sacrificial anode material) and the tube body material after brazing heating was 355 mV or more.

(3) Evaluation of fin joint failure at the time of core production The flat multi-hole tubes T1 to T37 and flat multi-hole tubes T38 to T55 obtained above were used as test materials, and fins were assembled to each flat multi-hole tube. Then, brazing heating was performed, and the presence or absence of a fin joint failure during the production of the heat exchanger core was verified.

Specifically, 80 μm-thick bare fins 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 T37 and flat multi-hole tubes T38 to T55. Assuming brazing heating for fin bonding when used as a heat transfer tube in an exchanger, a heat exchanger core is formed by heat treatment at 600 ° C. for 3 minutes, and then each heat exchanger core The fins joined to the flat multi-hole tube were cut and removed with a cutter, and the joining state of the fins was confirmed.

In Tables 11 and 12 below, heat exchanger cores are manufactured using the flat multi-hole tubes T1 to T37 and the flat multi-hole tubes T38 to T55 as test materials, and fin bonding of the heat exchanger cores after brazing heating The results of verifying the defects are shown respectively.

As is clear from the results in Table 11, no flat joints T1 to T37 were found to have poor fin joints in the heat exchanger core after brazing heating. Accordingly, it was confirmed that these flat multi-hole tubes T1 to T37 all have good fin bonding due to the presence of the sacrificial anode / brazing material portion (18).

In contrast, the flat multi-hole tubes T38, T39, and T55 shown in Table 12 are basically made of a conventional material or a tube body material made of a pure Al alloy without using a sacrificial anode / brazing material. Since it was the flat multi-hole pipe | tube used, the fin was unjoined in the heat exchanger core after brazing heating. Further, since the flat multi-hole tube T41 has a Si content of 0% by mass, defective fin bonding was caused. Further, the flat multi-hole tube T40 shown in Table 12 has a Si content of 14.0% by mass, and the flat multi-hole tube T43 has a Zn content of 8.0% by mass. Therefore, the sacrificial anode / brazing material part (18) melted during brazing heating, and through holes due to melting were observed in the base material. On the other hand, in the heat exchanger core using the flat multi-hole tubes T42, T44 to T54, no fin joint failure was observed.

(4) Evaluation of outer surface anticorrosion properties The flat multi-hole tubes T1 to T37 and flat multi-hole tubes T38 to T55 obtained as described above were used as test materials, and SWAAT tests prescribed in ASTM-G85-Annex A3 were performed. Implemented and verified the effect of each outer surface anticorrosion. This SWAAT test evaluates the outer surface anticorrosion property by repeatedly applying an artificial seawater spray and a wet environment under constant temperature conditions. Further, the corrosion test period was a three-level period of 10 days, 20 days and 30 days, the case where there was no penetration was evaluated as (◯), and the case where there was penetration was evaluated as (x).

Specifically, brazing heating for fin bonding when the flat multi-hole tubes T1 to T37 and flat multi-hole tubes T38 to T55 are used as heat transfer tubes in a heat exchanger is assumed. After heat treatment at 600 ° C. for 3 minutes, they were cut to a length of 100 mm in the longitudinal direction of extrusion, and both ends of the cut end face where the flow channel was exposed were masked with silicone resin. Moreover, the test liquid used for the SWAAT test produced the artificial seawater by ASTM D1141, and added acetic acid to this artificial seawater, and adjusted it to pH3. In addition, the test conditions were 0.5 hour spray-wet 1.5 hour as one cycle, and this cycle was repeated to conduct an external surface anticorrosion evaluation test for three levels of 10 days, 20 days, and 30 days. did. Note that the flat multi-hole tubes T40 and T43 in which the melting of the base material was significantly observed at the time of brazing heating were excluded from the test target.

Then, for the test material for which the outer surface anticorrosion evaluation test was completed, after peeling the silicone sealant resin at both ends, the test material surface was put into a phosphoric acid chromic acid solution heated at a heater. The corrosion product was removed, and the presence or absence of through-holes on the surface of the test material was examined. Specifically, a highly penetrable colored flaw detection liquid is dropped into each flow path of the flat multi-hole tube, and the penetration hole is confirmed by a method of confirming the exudation of the flaw detection liquid from the inner surface of the flat multi-hole pipe. The presence or absence was examined. Furthermore, after embedding the test material whose through-holes were embedded with an embedding resin, the cross-section was made with water-resistant paper for the maximum corroded part, and further mirror-finished by buffing. The corrosion situation of the pipe outer peripheral surface of the material was observed. In the SWAAT test of the test material used in the above test, penetration did not occur after 20 days, and when penetration was observed after 30 days or when it did not penetrate (◎), penetration occurred after 10 days. When it did not occur and penetration was observed after 20 days, it was evaluated as (◯), and when penetration was observed after 10 days, it was evaluated as (x).

Tables 13 and 14 below evaluate the SWAAT test for 10, 20, and 30 days for flat multi-hole tubes T1 to T37 and flat multi-hole tubes T38, T39, T41, T42, and T44 to T55. The results are shown respectively.

As apparent from the results in Table 13, it was confirmed that the flat multi-hole tubes T1 to T37 had no through-holes penetrating the outer peripheral wall portion (14) in the evaluation after 10 days of the SWAAT test. Further, in the evaluation after 20 days, through holes penetrating the outer peripheral wall portion (14) were confirmed in the flat multi-hole tubes T11, T13 to T15, T18, T19, T21, T27, T29, and T31 to T37. . Furthermore, in the evaluation after 30 days, through holes penetrating the outer peripheral wall portion (14) of the flat multi-hole tube excluding T1, T16 and T20 were observed. Therefore, it was recognized that all of the flat multi-hole tubes T1 to T37 were effectively protected from the outer surface by the sacrificial anode effect due to the presence of the sacrificial anode / brazing material portion (18).

On the other hand, the flat multi-hole tubes T38, T39, T55 shown in Table 14 are flat multi-hole tubes using only the tube body material similar to the conventional material without using the sacrificial anode / brazing material. When the SWAAT test was carried out on the 10th, 20th and 30th, it was recognized that corrosion holes penetrating the outer peripheral wall of the pipe were formed in all the evaluations after the test. This is because the sacrificial anode / brazing material portion (18) does not exist on the outer peripheral wall of the tube as in the flat multi-hole tube according to the present invention, so the sacrificial anode effect cannot be obtained and the outer surface anticorrosion effect cannot be exhibited. As a result, it was recognized that penetration occurred early.

In addition, the flat multi-hole tubes T41, T42, T44 to T55 shown in Table 14 were subjected to the SWAAT test similar to the above on the 10th, 20th and 30th. It was observed that corrosion holes were generated. All of the through portions were confirmed in the region of the outer peripheral wall portion of the pipe where the sacrificial anode / brazing material portion (18) was not formed. This is because, like the flat multi-hole tubes T38, T39, T55, the sacrificial anode / brazing material portion (18) does not exist on the outer peripheral wall portion (14), so that the sacrificial anode effect cannot be obtained and the outer surface It was recognized that penetration occurred early because the anticorrosion effect could not be exhibited.

DESCRIPTION OF SYMBOLS 10 Flat multi-hole pipe 12 Flow path 14 Pipe outer peripheral wall part 16 Internal partition part 18 Sacrificial anode and brazing material part 20 Composite billet 22 Billet for pipe main body material 24 Billet for sacrificial anode and brazing material 30 Single billet 32 Billet for pipe main body material

Claims (11)

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 channels extending in parallel to the tube axis direction independently of each other, and these channels are flat Aluminum extruded flat multi-hole pipes arranged in the longitudinal direction of various cross-sectional shapes,
Formed by extrusion using the aluminum material as the aluminum material, and a sacrificial anode / brazing material made of an Al—Si—Zn-based aluminum alloy that is electrochemically less basic than the aluminum tube body material. The sacrificial anode / brazing material is exposed to the entire outer peripheral wall portion of the tube or at least a part of the flat portion of the outer peripheral wall portion of the tube to form the sacrificial anode / brazing material portion. An aluminum extruded flat multi-hole tube excellent in brazing and outer surface anticorrosive properties, characterized by having The sacrificial anode / brazing material contains Si: 1.0 to 13.0% by mass and Zn: 0.1 to 7.0% by mass, with the balance being aluminum and an aluminum alloy that is an inevitable impurity, The said aluminum tube main body material contains Cu: 0.7 mass% or less and Mn: 1.4 mass% or less, The remainder consists of aluminum and the aluminum alloy which is an unavoidable impurity, The claim 1 characterized by the above-mentioned. Aluminum extruded flat multi-hole tube with excellent brazing and outer surface anticorrosion properties. The aluminum alloy constituting the sacrificial anode / brazing material further includes Mn: 1.4 mass% or less, Cr: 0.05 to 0.30 mass%, Zr: 0.05 to 0.30 mass%, Ti: Brazing property according to claim 2, containing one or more of 0.05 to 0.30% by mass and Sr: 0.0001 to 0.1% by mass Aluminum extruded flat multi-hole tube with excellent outer surface corrosion resistance. The aluminum alloy constituting the aluminum tube main body material further includes Cr: 0.05 to 0.30 mass%, Zr: 0.05 to 0.30 mass%, Ti: 0.05 to 0.30 mass%, and The brazing property and the outer surface anticorrosion property according to claim 2 or 3, characterized by containing one or more of Sr: 0.0001 to 0.1% by mass Aluminum extruded flat multi-hole tube. The sacrificial anode / brazing material 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. An aluminum extruded flat multi-hole tube excellent in brazing properties and outer surface anticorrosion properties according to any one of the above items. 6. The sacrificial anode / brazing material portion is present at a ratio of 50% or more and 100% or less of the peripheral length of the outer peripheral wall portion of the tube in a cross section of the tube. An aluminum extruded flat multi-hole tube excellent in brazing properties and outer surface anticorrosion properties according to any one of the above items. The brazing property and outer surface corrosion prevention according to any one of claims 1 to 6, wherein a potential difference between the sacrificial anode / brazing material and the aluminum tube main body material is 5 mV or more and 300 mV or less. Aluminum extruded flat multi-hole tube with excellent properties. The brazing property and outer surface according to any one of claims 1 to 7, wherein the extruded aluminum material is a composite billet composed of the aluminum tube main body material and the sacrificial anode / brazing material. Aluminum extruded flat multi-hole tube with excellent corrosion resistance. 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 sacrificial anode / brazing material, which is located around the core billet. Item 9. An aluminum extruded flat multi-hole tube excellent in brazing property and outer surface anticorrosion property according to Item 8. The aluminum extrusion flatness excellent in brazing property and outer surface anticorrosion property according to any one of claims 1 to 9, wherein the extrusion tube is formed by extrusion processing of the aluminum material using a porthole die. Multi-hole tube. It is comprised including the aluminum extrusion flat multi-hole pipe of any one of Claim 1 thru | or 10, 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.

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