Flow channel forming section and heat exchanger

Abstract

The present invention provides a heat exchanger that can reduce the environmental impact during the manufacturing process, suppress deformation during brazing heating, and facilitate the formation of brazed joints between components. [Solution] The heat exchanger 1 has a first flow path 11 and a plurality of flow path forming sections 2 arranged at intervals from each other, and a second flow path 12 formed between the flow path forming sections 2. The flow path forming section 2 has a first outer wall section 21 which constitutes the portion of the outer wall of the first flow path 11 that faces one of the two second flow paths 12 adjacent to the flow path forming section 2, a second outer wall section 22 which constitutes the portion that faces the other second flow path 12b, and a support section 23 which is arranged between both ends in the width direction of the flow path forming section 2 and is connected to both the first outer wall section 21 and the second outer wall section 22. The first outer wall section 21 and the second outer wall section 22 are made of an aluminum alloy plate 3 having a specific chemical composition.

Description

Technical Field

[0001] The present invention relates to a heat exchanger, a method for manufacturing the same, an aluminum alloy plate for forming a flow path, a tube material for a heat exchanger, and an outer wall material for a flow path of a heat exchanger.

Background Art

[0002] A heat exchanger may have a structure in which a first flow path through which a first heat transfer medium flows and a second flow path through which a second heat transfer medium flows are alternately arranged. For example, Patent Document 1 describes a radiator having a structure in which tubes and fins are alternately laminated. The tube in Patent Document 1 is composed of an aluminum alloy clad material including a core material, a sacrificial anode material laminated on a first surface of the core material, and a brazing material laminated on a second surface of the core material. Further, brazed joints made of the brazing material of the clad material are formed in gaps between edges of the clad material in the tube and in gaps between the tube and the fins.

[0003] On the other hand, in recent years, a single-layer aluminum alloy material configured to generate a small amount of molten liquid by heating and be brazed to a mating material has been proposed. As this type of aluminum alloy material, for example, Patent Document 2 describes an aluminum alloy material containing 1.0 to 5.0% by mass of Si and 0.01 to 2.00% by mass of Fe, with the balance being Al and unavoidable impurities.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, from the perspective of reducing the environmental impact during the manufacture of heat exchangers, it has become desirable to reuse the scraps generated during the manufacturing process of heat exchangers as casting raw materials. However, since the core material, sacrificial anode material, and brazing material in the clad material described in Patent Document 1 have different chemical compositions, the chemical composition of the molten metal obtained by melting the scraps of the clad material is different from that of the core material, sacrificial anode material, and brazing material. Therefore, when reusing the clad material described in Patent Document 1 as casting raw materials, it is necessary to use a large amount of new aluminum ingots, etc., in order to adjust the chemical composition of the molten metal to the desired range, and there are limits to the reduction of the environmental impact.

[0006] On the other hand, the aluminum material described in Patent Document 2 is configured to generate a small amount of molten material when heated, and therefore has a tendency to lose strength during brazing heating. As a result, when a tube is made using the aluminum material described in Patent Document 2, the tube easily deforms during brazing heating, making it difficult to form brazed joints in the gaps between the edges of the aluminum material in the tube or in the gaps between the tube and the fins.

[0007] This invention has been made in view of the above background, and aims to provide a heat exchanger, a method for manufacturing the same, an aluminum alloy plate for forming flow channels, a tube material for the heat exchanger, and an outer wall material for the flow channels of the heat exchanger, which can reduce the environmental burden in the manufacturing process, suppress deformation during brazing heating, and facilitate the formation of brazed joints between components. [Means for solving the problem]

[0008] One aspect of the present invention is a heat exchanger having a first flow path, a plurality of flow path forming sections arranged at intervals from each other, and a second flow path formed between the flow path forming sections, wherein a heat transfer medium in the first flow path and a heat transfer medium in the second flow path are configured to perform heat exchange, The aforementioned flow channel forming section is The outer wall portion of the first channel, which constitutes the portion of the first channel facing one of the two second channels adjacent to the channel forming portion, The outer wall portion of the first channel, which is the portion of the second channel that faces the other of the two second channels adjacent to the channel forming portion, It has a support portion that is positioned between both ends in the width direction of the flow channel forming portion and is connected to both the first outer wall portion and the second outer wall portion, The heat exchanger is made of an aluminum alloy plate in which the first outer wall portion and the second outer wall portion are composed of a chemical composition containing Si (silicon): 1.5% to 3.0% by mass, Fe (iron): 0.05% to 0.6% by mass, Mn (manganese): 0.3% to 2.0% by mass, with the remainder being Al (aluminum) and unavoidable impurities. [Effects of the Invention]

[0009] The flow path forming portion of the heat exchanger has a first outer wall portion and a second outer wall portion made of the aluminum alloy plate. Since the aluminum alloy plate is composed of a single layer of aluminum alloy having the specific chemical composition, molten metal having the same chemical composition as the original aluminum alloy plate can be easily obtained by melting the scraps of the aluminum alloy plate generated during the manufacturing process of the aluminum alloy plate and the manufacturing process of the heat exchanger obtained using the aluminum alloy plate. Furthermore, since the first outer wall portion and the second outer wall portion are components with a high mass ratio among the heat exchanger, the environmental burden during the manufacturing process of the heat exchanger can be easily reduced by constructing the first outer wall portion and the second outer wall portion from the aluminum alloy plate.

[0010] Furthermore, the flow channel forming section has a support section positioned between its two ends in the width direction and connected to both the first outer wall section and the second outer wall section. By providing the support section between the two ends in the width direction of the flow channel forming section in this way, the rigidity of the flow channel forming section can be increased. As a result, deformation of the first outer wall section and the second outer wall section during brazing can be suppressed, and the state in which the first outer wall section and the second outer wall section are in contact can be easily maintained during brazing heating.

[0011] And since the aluminum alloy plate has the specific chemical composition, a small amount of molten liquid can be generated by heating. Therefore, brazing joints can be easily formed between the first outer wall portion and the second outer wall portion by the molten liquid generated from the aluminum alloy plate.

[0012] Therefore, according to the above aspect, it is possible to provide a heat exchanger that can reduce the environmental load in the manufacturing process, suppress deformation during brazing heating, and easily form brazing joints between component parts.

Brief Description of the Drawings

[0013] [Figure 1] FIG. 1 is a front view of the heat exchanger in Example 1. [Figure 2] FIG. 2 is a partially enlarged view of FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view taken along the arrow III-III in FIG. 2. [Figure 4] FIG. 4 is a partial cross-sectional view showing the main part of the heat exchanger in Example 2. [Figure 5] FIG. 5 is a partial cross-sectional view showing the main part of the heat exchanger in Example 3. [Figure 6] FIG. 6 is a perspective view of the aluminum alloy plate constituting the flow path forming portion in Example 3. [Figure 7] FIG. 7 is a partial cross-sectional view showing the main part of the heat exchanger in Example 4. [Figure 8] FIG. 8 is a perspective view of the aluminum alloy plate constituting the flow path forming portion in Example 4. [Figure 9] FIG. 9 is a perspective view of the mini-core test body in Experimental Example 1. [Figure 10] FIG. 10 is an explanatory view of the natural electrode potential measuring device in Experimental Example 1.

Modes for Carrying Out the Invention

[0014] (Heat Exchanger) The heat exchanger has a plurality of flow path forming portions arranged at intervals from each other. The flow path forming portion has a first outer wall portion, a second outer wall portion, and a first flow path formed by a space surrounded by the first outer wall portion and the second outer wall portion. Further, a second flow path is formed between adjacent flow path forming portions. Therefore, the first flow path and the second flow path in the heat exchanger are alternately arranged, and the heat exchanger is configured to be able to perform heat exchange between the heat transfer medium in the first flow path and the heat transfer medium in the second flow path.

[0015] The flow path forming portion has a first outer wall portion, a second outer wall portion, and a support portion. The specific shape of the flow path forming portion is not particularly limited and can take various forms. For example, the flow path forming portion may be a flat tube having an oval or rectangular cross-sectional shape in a cross-section perpendicular to its extending direction. Further, the flow path forming portion may have a shape in which the first flow path and the support portion are alternately continuous in the width direction. Furthermore, the flow path forming portion may have a shape in which two flat plates are laminated on each other.

[0016] The first outer wall portion and the second outer wall portion are composed of an aluminum alloy plate having the specific chemical component. The first outer wall portion and the second outer wall portion may be composed of a common aluminum alloy plate or may be composed of separate aluminum alloy plates.

[0017] More specifically, for example, by bending a single aluminum alloy plate into a cylindrical shape and joining the end faces thereof by brazing, a flow path forming portion in which the first outer wall portion and the second outer wall portion are composed of a common aluminum alloy plate can be obtained. Also, for example, by preparing an aluminum alloy plate constituting the first outer wall portion and an aluminum alloy plate constituting the second outer wall portion and joining the end faces of these aluminum alloy plates through brazing, a flow path forming portion in which the first outer wall portion and the second outer wall portion are composed of separate aluminum alloy plates can be obtained. The more detailed configuration of the aluminum alloy plates constituting the first outer wall portion and the second outer wall portion will be described later.

[0018] The support portion of the channel forming section is positioned between both ends of the channel forming section in the width direction and is connected to both the first outer wall section and the second outer wall section. By providing the support portion connected to both the first and second outer wall sections at the aforementioned specific position, the rigidity of the channel forming section can be structurally increased. Therefore, even when the channel forming section is compressed in the direction of alignment between the first and second channels during brazing heating, deformation of the channel forming section can be suppressed.

[0019] Furthermore, the aforementioned "between both ends in the width direction of the flow channel forming section" refers to a position in the width direction of the flow channel forming section that can support the load applied to the central part of the first outer wall section and the central part of the second outer wall section. More specifically, for example, if the flow channel forming section has one first flow channel, the support section should be positioned between one end and the other end of the first flow channel in the width direction of the flow channel forming section. Also, for example, if the flow channel forming section has multiple first flow channels, the support section should be positioned between the first flow channel located at one end in the width direction of the flow channel forming section and the first flow channel located at the other end.

[0020] The specific form of the support portion is not particularly limited, and various forms can be taken as long as the rigidity of the flow path forming portion can be increased. For example, the flow path forming portion may have one support portion or two or more support portions. From the viewpoint of distributing the load applied to the flow path forming portion and further increasing the rigidity of the flow path forming portion, it is preferable that the flow path forming portion has multiple support portions.

[0021] While the arrangement of the support members is not particularly limited, it is preferable that at least one support member be located in the center of the flow channel forming section in the width direction, from the viewpoint of more easily increasing the rigidity of the flow channel forming section.

[0022] The support portion may be made of an aluminum alloy plate common to at least one of the first outer wall portion and the second outer wall portion. That is, at least one of the first outer wall portion and the second outer wall portion and the support portion may be provided on the same aluminum alloy plate. When the first outer wall portion and / or the second outer wall portion and the support portion are provided on a common aluminum alloy plate, a part of the aluminum alloy plate can be made to protrude by press working or the like to form a protruding portion, and this protruding portion can be joined to the mating material by brazing to form the support portion. In this case, various shapes such as dimple shape or groove shape can be adopted for the shape of the support portion. Alternatively, for example, the support portion can be formed in the center of the flow channel forming portion in the width direction by folding back both ends in the width direction of the aluminum alloy plate and joining them to the center in the width direction.

[0023] Furthermore, the support portion may be made of an aluminum material different from the aluminum alloy plates that constitute the first and second outer walls. In this case, the rigidity of the flow channel forming portion can be increased by joining the support portion to the first and second outer walls via brazing. When the support portion is made of an aluminum material different from the first and second outer walls, the form of the aluminum material constituting the support portion is not particularly limited. For example, the support portion may be made of a single layer of aluminum. In this case, the chemical composition of the aluminum material can be appropriately selected from known aluminum and aluminum alloys according to the desired strength, corrosion resistance, etc. Furthermore, the aluminum material constituting the support portion may have the same chemical composition as the aluminum alloy plates that constitute the first and second outer walls.

[0024] Furthermore, the support portion may be composed of a clad material comprising, for example, a core material and a layer material laminated on the core material. In this case, the chemical composition of the core material can be appropriately selected from known aluminum and aluminum alloys according to the desired strength, corrosion resistance, etc. The layer material may be, for example, a brazing material or a sacrificial anode material.

[0025] When the support portion is made of an aluminum material different from the aluminum alloy plates that constitute the first and second outer walls, the shape of the support portion is not particularly limited and can take various shapes such as columnar or wall-shaped. From the viewpoint of increasing the rigidity of the flow channel forming portion and performing heat exchange more efficiently, it is preferable that the support portion be an inner fin. As an inner fin, for example, a corrugated fin having a wavy cross-sectional shape in a cross section perpendicular to the extension direction can be used. A corrugated fin has multiple peaks that abut against the first and second outer walls, respectively. Therefore, by using a corrugated fin as an inner fin, the load applied to the first and second outer walls can be distributed to these peaks. As a result, the rigidity of the flow channel forming portion can be further increased.

[0026] The heat exchanger preferably has an outer fin provided in the second flow path, and the outer fin is joined to the first outer wall and the second outer wall by brazing. By providing an outer fin in the second flow path, the spacing between adjacent flow path forming parts is more easily maintained. Therefore, in this case, deformation of the flow path forming parts during brazing can be more easily suppressed. In addition, by providing an outer fin in the second flow path, the heat exchange efficiency of the heat exchanger can be further improved.

[0027] The outer fins may be made of aluminum or an aluminum alloy. Preferably, the natural electrode potential of the outer fins is lower than the natural electrode potential of the first outer wall, the second outer wall, and the fillet of the brazed joint joining these outer walls to the outer fins. In this case, the outer fins function as sacrificial anodes for the first outer wall, the second outer wall, and the brazed joint, suppressing corrosion of these parts over a long period. As a result, the corrosion resistance of the entire heat exchanger can be further improved.

[0028] In the heat exchanger, the outer fins that can function as sacrificial anodes may be made of an aluminum alloy containing, for example, Zn: 0.5% by mass or more and 6% by mass or less.

[0029] As the outer fin, for example, a corrugated fin having a wavy cross-sectional shape in a cross-section perpendicular to the extension direction can be used. The corrugated fin has multiple peaks that abut the flow channel forming section. Therefore, by using a corrugated fin as the outer fin, the load applied to the flow channel forming section can be distributed to these peaks. As a result, deformation of the flow channel forming section during brazing can be suppressed more effectively.

[0030] The heat exchanger can be applied to a variety of uses. For example, the heat exchanger may be configured as an automotive heat exchanger installed in an automobile, such as a radiator, condenser, evaporator, heater core, oil cooler, intercooler, chiller, or battery cooler. The heat exchanger may also be configured as an air conditioning system heat exchanger incorporated into, for example, the indoor or outdoor unit of an air conditioning system. Furthermore, the heat exchanger may be configured as a heat exchanger incorporated into heavy machinery.

[0031] (Method of manufacturing a heat exchanger) The heat exchanger is manufactured by assembling components of the heat exchanger, including a flow path forming section, to create an assembly. The assembly is obtained by heating and brazing under conditions such that the time required to reach 575°C from 450°C is between 4 minutes and 15 minutes, and the time required to reach 615°C from 575°C is between 5 minutes and 40 minutes.

[0032] The assembly includes at least a channel forming section. The assembly may also include components other than the channel forming section, as needed, such as a header tank for distributing the heat transfer medium to the first channel or for merging the heat transfer medium that has flowed out of the first channel, and outer fins placed between the channel forming sections. When assembling the assembly, flux may be applied to the parts to be brazed, as needed. As the flux, for example, fluoride-based fluxes such as KAlF4, K2AlF5, K2AlF5·H2O, K3AlF6, AlF3, KZnF3, and K2SiF6, cesium-based fluxes such as Cs3AlF6, CsAlF4·2H2O, and Cs2AlF5·H2O, and chloride-based fluxes, which are compounds used as fluxes for aluminum brazing, can be used.

[0033] The components used in the assembly may be pre-etched. By etching the components and removing at least a portion of the oxide film present on their surfaces, brazed joints can be formed more easily during the subsequent brazing heating process. In particular, when attempting to form brazed joints using so-called flux-free brazing, which does not use flux during brazing, it is preferable to pre-etch the components.

[0034] The etching method is not particularly limited; for example, a method involving contact with an acid or alkali can be employed. In etching, the oxide film present on the surface of the component may be completely removed, or only a portion of the oxide film may be removed. Furthermore, after etching is complete, post-treatment such as rinsing with water or removal of smut may be performed as needed.

[0035] After fabricating the assembly, the assembly is heated and brazed under conditions such that the time required to reach 575°C from 450°C is between 4 and 15 minutes, and the time required to reach 615°C from 575°C is between 5 and 40 minutes. The aluminum alloy plate having the specified chemical composition has a liquid phase ratio of 5% to 35% by mass when heated under the specified conditions. Therefore, by heating the assembly under the specified conditions, deformation of the flow path forming portion can be suppressed while generating a small amount of molten material from the aluminum alloy plate. Consequently, by heating the assembly under the specified conditions, a brazed joint can be formed between the aluminum alloy plate and the components in contact with it, thereby obtaining a heat exchanger.

[0036] From the viewpoint of suppressing oxidation of components during brazing, it is preferable that the atmosphere during brazing be an inert gas atmosphere. As the inert gas, for example, nitrogen or argon can be used. The dew point of the inert gas is preferably -35°C or lower, more preferably -50°C or lower, and particularly preferably -60°C or lower. Furthermore, the oxygen concentration in the inert gas atmosphere is preferably 200 ppm by volume or lower, more preferably 100 ppm by volume or lower, even more preferably 10 ppm by volume or lower, and particularly preferably 5 ppm by volume or lower.

[0037] (Aluminum alloy plate) The first and second outer walls of the heat exchanger are made of a flow channel forming aluminum alloy plate (hereinafter referred to as "aluminum alloy plate") having a chemical composition containing Si: 1.5% to 3.0% by mass, Fe: 0.05% to 0.6% by mass, Mn: 0.3% to 2.0% by mass, with the remainder being Al and unavoidable impurities. The chemical composition of the aluminum alloy plate and the reasons for its limitations are described below.

[0038] ·Si: 1.5% by mass or more and 3.0% by mass or less The aluminum alloy sheet contains 1.5% by mass or more and 3.0% by mass or less of Si as an essential component. By setting the Si content in the aluminum alloy sheet to 1.5% by mass or more, a melt containing Al and Si is generated during brazing, and a brazed joint can be formed between the first outer wall portion and the second outer wall portion and the components that abut these outer walls. The Si content in the aluminum alloy sheet is preferably 1.7% by mass or more, more preferably 1.9% by mass or more, even more preferably 2.0% by mass or more, and particularly preferably 2.2% by mass or more. In this case, the amount of melt generated during brazing can be increased, and the brazing performance can be further improved. If the Si content is less than 1.5% by mass, the amount of melt generated during brazing will be insufficient, which may lead to a deterioration in brazing performance.

[0039] On the other hand, if the Si content is excessively high, the amount of melting of the aluminum alloy sheet during brazing will increase, which may lead to a decrease in the strength of the aluminum alloy sheet. As a result, the assembly may become more prone to deformation during brazing. From the viewpoint of avoiding such problems, the Si content should be 3.0 mass% or less. From a similar viewpoint, it is preferable that the Si content be 2.8 mass% or less.

[0040] In determining the preferred range for the Si content in the aluminum alloy sheet, the upper and lower limits of the Si content mentioned above can be arbitrarily combined. For example, the preferred range for the Si content in the aluminum alloy sheet may be 1.7% by mass or more and 3.0% by mass or less, 1.9% by mass or more and 3.0% by mass or less, 2.0% by mass or more and 3.0% by mass or less, or 2.2% by mass or more and 2.8% by mass or less.

[0041] • Fe (iron): 0.05% by mass or more, 0.6% by mass or less The aluminum alloy sheet contains 0.05% by mass or more and 0.6% by mass of Fe as an essential component. Fe is dispersed as a precipitate in the aluminum alloy sheet and has the effect of suppressing the decrease in strength of the aluminum alloy sheet at high temperatures. By setting the Fe content to 0.05% by mass or more, this effect can be fully obtained. From the viewpoint of more effectively suppressing the decrease in strength of the aluminum alloy sheet at high temperatures, it is preferable that the Fe content be 0.10% by mass or more. If the Fe content is less than 0.05% by mass, it may lead to a decrease in the strength of the aluminum alloy sheet at high temperatures, and the assembly may become more prone to deformation during brazing. In addition, in this case, it becomes necessary to use high-purity metal as the raw material for the aluminum alloy sheet, which may lead to an increase in the material cost of the aluminum alloy sheet.

[0042] On the other hand, if the Fe content is excessively high, coarse intermetallic compounds are more likely to form during the manufacturing process of the aluminum alloy sheet, which may lead to a decrease in the manufacturability of the aluminum alloy sheet. In this case, the crystal grains of the Al matrix are more likely to be refined due to recrystallization during brazing. As a result, the grain boundary density of the Al matrix increases, which may make the aluminum alloy sheet more prone to buckling. These problems can be easily avoided by keeping the Fe content in the aluminum alloy sheet to 0.6 mass% or less.

[0043] ·Mn: 0.3 mass% or more and 2.0 mass% or less The aluminum alloy sheet contains 0.3% to 2.0% by mass of Mn as an essential component. Mn forms an Al-Mn-Si intermetallic compound in the aluminum alloy sheet, improving its strength through dispersion strengthening. In addition, Mn dissolves in the Al matrix, improving the strength of the aluminum alloy sheet through solid solution strengthening.

[0044] By setting the Mn content in the aluminum alloy sheet to 0.3% by mass or more, the strength of the aluminum alloy sheet can be improved through dispersion strengthening and solid solution strengthening. Furthermore, the aforementioned dispersion strengthening and solid solution strengthening can suppress the decrease in strength, buckling, and deformation of the aluminum alloy sheet during brazing. As a result, deformation of the assembly during brazing can be suppressed. If the Mn content is less than 0.3% by mass, the effect of Mn on improving strength will be reduced, and the assembly may become more susceptible to deformation during brazing.

[0045] On the other hand, if the Mn content is excessively high, coarse intermetallic compounds are more likely to form during the manufacturing process of the aluminum alloy sheet. If rolling is performed while these coarse intermetallic compounds are present, there is a risk of pinhole formation. To avoid this problem, the Mn content should be 2.0% by mass or less.

[0046] In addition to the essential components mentioned above, the aluminum alloy plate may contain, as an optional component, one or more elements selected from the group consisting of Cu (copper): 0.8% by mass or less, Zn (zinc): 6.0% by mass or less, Ti (titanium): 0.3% by mass or less, Mg (magnesium): 0.2% by mass or less, V (vanadium): 0.3% by mass or less, Zr (zirconium): 0.3% by mass or less, Cr (chromium): 0.3% by mass or less, Bi (bismuth): 0.1% by mass or less, Ni (nickel): 0.6% by mass or less, Sn (tin): 0.3% by mass or less, In (indium): 0.3% by mass or less, Sr (strontium): 0.1% by mass or less, Na (sodium): 0.1% by mass or less, Sb (antimony): 0.3% by mass or less, and Ca (calcium): 0.5% by mass or less.

[0047] ·Cu: 0.8% by mass or less The aluminum alloy sheet may contain, as an optional component, 0.8% by mass or less of Cu. Cu has the effect of improving the strength of the aluminum alloy sheet by solid dissolving in the Al matrix. Furthermore, Cu is easily concentrated in the brazed joint formed after brazing and has the effect of nourishing the potential of the brazed joint.

[0048] By increasing the Cu content in the aluminum alloy sheet to more than 0% by mass, the strength of the aluminum alloy sheet can be further improved, the potential of the brazed joint can be nourished, and the corrosion resistance of the brazed joint can be further improved. From the viewpoint of more reliably obtaining these effects, the Cu content in the aluminum alloy sheet is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.3% by mass or more.

[0049] On the other hand, by setting the Cu content to 0.8% by mass or less, more preferably 0.7% by mass or less, the amount of melting of the aluminum alloy plate during brazing can be easily adjusted to an appropriate range. As a result, deformation of the assembly during brazing can be suppressed more easily.

[0050] In determining the preferred range of Cu content in the aluminum alloy sheet, the upper and lower limits of Cu content mentioned above can be arbitrarily combined. For example, the preferred range of Cu content in the aluminum alloy sheet may be 0% by mass or more and 0.8% by mass or less, 0.05% by mass or more and 0.8% by mass or less, 0.1% by mass or more and 0.8% by mass or less, 0.1% by mass or more and 0.7% by mass or less, or 0.3% by mass or more and 0.7% by mass or less.

[0051] The total amount of Fe and Cu in the aluminum alloy sheet is preferably greater than 0.65 mass%, more preferably 0.68 mass% or more, and even more preferably 70 mass% or more. In this case, the strength of the aluminum alloy sheet can be further improved. As a result, deformation of the assembly during brazing can be suppressed more easily. On the other hand, the total amount of Fe and Cu in the aluminum alloy sheet may be 1.4 mass% or less, 1.2 mass% or less, 1.0 mass% or less, or 0.80 mass% or less.

[0052] In determining a preferred range for the sum of Fe and Cu content in the aluminum alloy sheet, the upper and lower limits of the sum of Fe and Cu content mentioned above can be arbitrarily combined. For example, a preferred range for the sum of Fe and Cu content may be greater than 0.65 mass% and 1.4 mass% or less, greater than 0.65 mass% and 1.2 mass% or less, 0.68 mass% or more and 1.0 mass% or less, 0.68 mass% or more and 1.0 mass% or less, or 0.70 mass% or more and 0.80 mass% or less.

[0053] ·Zn: 6.0% by mass or less The aluminum alloy plate may contain 6.0% by mass or less of Zn as an optional component. Zn has the effect of lowering the potential of the aluminum alloy plate. Therefore, by adding 6.0% by mass or less of Zn to the aluminum alloy plate, the potential balance between the aluminum alloy plate and other components can be more easily maintained within an appropriate range. As a result, the corrosion resistance of the entire heat exchanger can be further improved.

[0054] From the viewpoint of further improving the corrosion resistance of the heat exchanger, it is preferable that the aluminum alloy plate contains Cu: 0.1% to 0.8% by mass and Zn: 1.0% by mass or less. In this case, the natural electrode potential of the brazed joint formed between the aluminum alloy plate and other components can be appropriately nourished, improving the self-corrosion resistance of the brazed joint. Therefore, by joining the aluminum alloy plate to a component that can function as a sacrificial anode for the aluminum alloy plate, such as an outer fin, via such a brazed joint, the joined state can be maintained for a long period of time. As a result, the corrosion resistance of the entire heat exchanger can be further improved.

[0055] From the viewpoint of more reliably obtaining the effects described above, the Cu content in the aluminum alloy sheet is preferably 0.2% by mass or more and 0.8% by mass or less, more preferably 0.3% by mass or more and 0.8% by mass or less, and even more preferably 0.4% by mass or more and 0.8% by mass or less. From a similar viewpoint, the Zn content in the aluminum alloy sheet is preferably 0.7% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.3% by mass or less.

[0056] The preferred ranges for Cu content and Zn content mentioned above can be combined in any way. For example, the aluminum alloy sheet may contain Cu: 0.2% to 0.8% by mass and Zn: 0.7% by mass or less, or Cu: 0.3% to 0.8% by mass and Zn: 0.5% by mass or less, or Cu: 0.4% to 0.8% by mass and Zn: 0.3% by mass or less.

[0057] ·Mg: 0.2% by mass or less The aluminum alloy sheet may contain, as an optional component, 0.2% by mass or less of Mg. Mg has the effect of destroying the oxide film present on the surface of the aluminum alloy sheet and on the surface of the components joined to the aluminum alloy sheet. Therefore, by adding 0.2% by mass or less of Mg to the aluminum alloy sheet, the assembly can be brazed by so-called flux-free brazing, which does not use flux. From the viewpoint of further improving the brazing performance in flux-free brazing, the Mg content in the aluminum alloy sheet is preferably 0.005% by mass or more and 0.2% by mass or less.

[0058] On the other hand, in the so-called flux brazing method, which uses flux for brazing, the flux used for brazing reacts with Mg, which can lead to a deterioration in brazing properties. From the viewpoint of more easily avoiding such problems, it is preferable that the Mg content in the aluminum alloy sheet is 0.05% by mass or less.

[0059] ·Ti: 0.3% by mass or less, V: 0.3% by mass or less The aluminum alloy sheet may contain, as an optional component, one or two elements from Ti: 0.3% by mass or less and V: 0.3% by mass or less. Ti and V have the effect of improving the strength of the aluminum alloy sheet by solid dissolving in the Al matrix. Furthermore, Ti and V are distributed in layers within the aluminum alloy sheet and have the effect of suppressing the progression of corrosion in the thickness direction of the aluminum alloy sheet. On the other hand, if the Ti content or V content becomes excessively high, coarse precipitates are more likely to form during the manufacturing process of the aluminum alloy sheet, which may lead to a decrease in plastic workability.

[0060] By setting the Ti content and V content in the aluminum alloy sheet to preferably 0.3% by mass or less, and more preferably 0.2% by mass or less, the strength and self-corrosion resistance of the aluminum alloy sheet can be further improved while avoiding the formation of coarse precipitates.

[0061] ·Zr: 0.3% by mass or less The aluminum alloy sheet may contain 0.3% by mass or less of Zr as an optional component. Zr increases the strength of the aluminum alloy sheet before and after brazing, and also coarses the grain size after brazing, thereby improving its resistance to high-temperature buckling and brazing properties. On the other hand, if the Zr content in the aluminum alloy sheet is excessively high, coarse precipitates tend to form during the manufacturing process of the aluminum alloy sheet.

[0062] By keeping the Zr content in the aluminum alloy sheet within the specified range, the strength of the aluminum alloy sheet before and after brazing can be further improved while avoiding the formation of coarse precipitates. In this case, deformation of the assembly during brazing can be more effectively suppressed, and the brazing properties can be further improved.

[0063] ·Cr: 0.3% by mass or less The aluminum alloy sheet may contain 0.3% by mass or less of Cr as an optional component. Cr has the effect of improving the strength of the aluminum alloy sheet by solid dissolving in the Al matrix. Furthermore, when an aluminum alloy sheet containing Cr is heated, Al-Cr intermetallic compounds precipitate in the aluminum alloy sheet. These precipitates have the effect of coarsening the crystal grains after heating. On the other hand, if the Cr content in the aluminum alloy sheet is excessively high, coarse precipitates tend to form during the manufacturing process of the aluminum alloy sheet.

[0064] By keeping the Cr content in the aluminum alloy plate within the specified range, it is possible to improve the strength of the aluminum alloy plate while avoiding the formation of coarse precipitates, and to coarse the crystal grains after heating.

[0065] ·Bi: 0.1% by mass or less The aluminum alloy sheet may contain, as an optional component, 0.1% by mass or less of Bi. Bi has the effect of improving the fluidity of the molten metal produced by brazing heating. In addition, Bi has the effect of weakening the oxide film present on the surface of the aluminum alloy sheet and on the surface of the components joined to the aluminum alloy sheet. Therefore, by adding 0.1% by mass or less of Bi to the aluminum alloy sheet, brazing of the assembly can be performed by flux-free brazing. From the viewpoint of further improving the brazing properties in flux-free brazing, it is preferable that the aluminum alloy sheet contains both 0.1% by mass or less of Bi and 0.2% by mass or less of Mg.

[0066] ·Ni: 0.6% by mass or less The aluminum alloy sheet may contain 0.6% by mass or less of Ni as an optional component. Ni forms intermetallic compounds in the aluminum alloy sheet, improving the strength of the brazed aluminum alloy sheet through dispersion strengthening. On the other hand, if the Ni content is excessively high, coarse intermetallic compounds are more likely to form in the aluminum alloy sheet, which may lead to a deterioration in plastic workability. In this case, it may also lead to a decrease in the self-corrosion resistance of the aluminum alloy sheet. By setting the Ni content in the aluminum alloy sheet to 0.6% by mass or less, these problems can be avoided while further improving the strength of the brazed aluminum alloy sheet.

[0067] ·Sn: 0.3% by mass or less, In: 0.1% by mass or less The aluminum alloy plate may contain, as an optional component, one or two elements from among Sn: 0.3% by mass or less and In: 0.1% by mass or less. Sn and In have the effect of lowering the natural electrode potential of the aluminum alloy plate. By setting the content of Sn and In in the aluminum alloy plate within the specified range, the natural electrode potential of the aluminum alloy plate can be more easily adjusted to a desired range.

[0068] ·Sr: 0.1% by mass or less, Na: 0.1% by mass or less, Sb: 0.3% by mass or less, Ca: 0.5% by mass or less The aluminum alloy sheet may contain, as an optional component, one or more elements selected from the group consisting of Sr: 0.1% by mass or less, Na: 0.1% by mass or less, Sb: 0.3% by mass or less, and Ca: 0.5% by mass or less. These elements have the effect of refining the Si particles in the aluminum alloy sheet and uniformly dispersing the Si particles on the surface of the aluminum alloy sheet. Since Si particles serve as the starting point for melt formation, uniformly dispersing Si particles on the surface of the aluminum alloy sheet allows for the uniform formation of melt on the surface of the aluminum alloy sheet, making it easier to form a brazed joint between the aluminum alloy sheet and the component in contact with it. Preferably, the content of Sr, Na, Sb, and Ca is 0.05% by mass or less for each element.

[0069] From the viewpoint of ensuring brazing properties and more effectively suppressing deformation of the assembly during brazing, it is preferable that the aluminum alloy sheet contains Si: 1.5% to 3.0% by mass, Fe: 0.05% to 0.6% by mass, Mn: 0.3% to 2.0% by mass, Cu: 0% to 0.8% by mass, and Zn: greater than 0% to 6.0% by mass, with the remainder being Al and unavoidable impurities. From a similar viewpoint, it is preferable that the aluminum alloy sheet contains Si: 1.5% to 3.0% by mass, Fe: 0.05% to 0.6% by mass, Mn: 0.3% to 2.0% by mass, Cu: 0.1% to 0.8% by mass, and Zn: greater than 0% to 6.0% by mass, with the remainder being Al and unavoidable impurities. From a similar viewpoint, it is preferable that the aluminum alloy sheet contains Si: 1.5% to 3.0% by mass, Fe: 0.05% to 0.6% by mass, Mn: 0.3% to 2.0% by mass, Cu: 0.1% to 0.8% by mass, and Zn: greater than 0% to 1.0% by mass, with the sum of the Fe and Cu content exceeding 0.65% by mass and being 1.4% by mass or less, and the remainder consisting of Al and unavoidable impurities.

[0070] From a similar viewpoint, it is even more preferable that the aluminum alloy sheet contains Si: 1.5% to 2.8% by mass, Fe: 0.05% to 0.6% by mass, Mn: 0.3% to 2.0% by mass, Cu: 0.3% to 0.7% by mass, and Zn: greater than 0% to 6.0% by mass, with the sum of the Fe and Cu content being 0.68% to 1.0% by mass, and the remainder consisting of Al and unavoidable impurities. Furthermore, it is particularly preferable that the aluminum alloy sheet contains Si: 1.5% to 2.8% by mass, Fe: 0.05% to 0.6% by mass, Mn: 0.3% to 2.0% by mass, Cu: 0.3% to 0.7% by mass, Zn: greater than 0% to 6.0% by mass, and Sr: 0.1% by mass or less, with the total content of Fe and Cu being 0.68% to 1.0% by mass, and the remainder being Al and unavoidable impurities.

[0071] Other elements Furthermore, the aluminum alloy sheet may contain elements such as Ag, B, Be, Cd, Co, Ga, Ge, Hg, Li, Mo, P, Pb, and Y as unavoidable impurities. The content of these elements as unavoidable impurities is usually 0.05% by mass or less for each element. Preferably, the total amount of unavoidable impurities contained in the aluminum alloy sheet is 0.15% by mass or less.

[0072] Thickness The thickness of the aluminum alloy plate can be appropriately set according to the application and performance of the heat exchanger, the pressure of the heat transfer medium, etc. For example, the thickness of the aluminum alloy plate may be between 0.03 mm and 5.0 mm.

[0073] ·Manufacturing method The method for manufacturing the aluminum alloy sheet can take various forms. For example, the aluminum alloy sheet may be manufactured by a continuous casting method, or by rolling an ingot obtained by DC casting.

[0074] As a continuous casting method, twin-roll continuous casting and rolling methods and twin-belt continuous casting methods can be employed. When producing the aluminum alloy sheet using the twin-roll continuous casting and rolling method, it is preferable to set the casting speed to 0.5 m / min or more and 3 m / min or less. In the twin-roll continuous casting and rolling method, setting the casting speed to 0.5 m / min or more allows for a sufficiently high cooling rate during casting, making it easy to refine the second phase particles in the aluminum alloy sheet. Furthermore, setting the casting speed to 3 m / min or less allows for sufficient cooling and solidification of the molten metal during casting.

[0075] Furthermore, the temperature of the molten metal during casting is preferably between 650°C and 800°C, and more preferably between 680°C and 750°C. By setting the temperature of the molten metal preferably above 650°C, and more preferably above 680°C, the formation of large crystals in the molten metal can be avoided. Also, by setting the temperature of the molten metal preferably below 800°C, and more preferably below 750°C, the molten metal can be sufficiently cooled and solidified during casting.

[0076] The thickness of the cast sheet obtained by the continuous casting method is preferably 2 mm to 10 mm, and more preferably 4 mm to 8 mm. By making the thickness of the cast sheet preferably 2 mm or more, and more preferably 4 mm or more, sound cast sheets can be stably manufactured. Furthermore, by making the thickness of the cast sheet preferably 10 mm or less, and more preferably 8 mm or less, it becomes easier to wind the cast sheet onto a roll after casting.

[0077] The cast sheet obtained by the continuous casting method may be used as is as the aluminum alloy sheet. Alternatively, the thickness and temper can be adjusted by cold rolling, heat treatment, etc., of the cast sheet to obtain an aluminum alloy sheet with a desired thickness and temper. The aluminum alloy sheet may have a temper represented by temper symbols O, H1n, or H2n, for example. From the viewpoint of suppressing erosion during brazing, it is preferable that the aluminum alloy sheet has a temper represented by temper symbols H1n or H2n.

[0078] Furthermore, when producing the aluminum alloy sheet by rolling the ingot obtained by DC casting, the casting speed is preferably 20 mm / min or more and 100 mm / min or less, and more preferably 30 mm / min or more and 80 mm / min or less. In DC casting, by setting the casting speed preferably to 20 mm / min or more, more preferably to 30 mm / min or more, the cooling rate during casting can be sufficiently increased, and the second phase particles in the aluminum alloy sheet can be easily refined. Also, by setting the casting speed preferably to 100 mm / min or less, more preferably to 80 mm / min or less, the molten metal can be sufficiently cooled and solidified during casting.

[0079] When producing a slab by DC casting, the slab thickness is preferably 600 mm or less, and more preferably 500 mm or less. In this case, the cooling rate during casting can be sufficiently increased, making it easy to refine the second phase particles in the aluminum alloy plate.

[0080] After producing an ingot by DC casting, an aluminum alloy sheet with a desired thickness can be obtained by rolling the ingot. Hot rolling and cold rolling can be appropriately combined during the rolling process. Furthermore, heat treatments such as homogenization and annealing can be performed as needed between the start and completion of rolling to adjust the quality of the aluminum alloy sheet. The aluminum alloy sheet may have a quality represented by, for example, quality symbols O, H1n, or H2n. From the viewpoint of suppressing erosion during brazing, it is preferable that the aluminum alloy sheet has a quality represented by quality symbols H1n or H2n.

[0081] (Tubing material for heat exchangers) A tube material for a heat exchanger can be obtained by forming the aluminum alloy plate. The shape of the tube material for a heat exchanger can take various forms. For example, a tube material for a heat exchanger having a cylindrical shape can be obtained by forming the aluminum alloy plate into a cylindrical shape. The tube material for a heat exchanger may be, for example, a flat tube having an oval cross-sectional shape in a cross section perpendicular to its extending direction. In this case, for example, it is preferable that a convex portion is formed on at least one of the two opposing flat plate portions of the flat tube, and the tip of the convex portion abuts against the other flat plate portion. By brazing such a tube material, a support portion including a convex portion and a brazed joint that joins the convex portion and the flat plate portion can be formed on the tube material.

[0082] Furthermore, for example, by folding both ends of the aluminum alloy plate in the width direction toward the center, a heat exchanger tube material having a substantially B-shaped cross-sectional shape in a cross section perpendicular to the extending direction can be obtained. The tube material obtained in this way has a flat plate portion originating from the central part in the width direction of the aluminum alloy plate, and folded portions formed by folding both ends of the aluminum alloy plate in the width direction toward the central part. The tip of the folded portion faces the flat plate portion. By brazing a heat exchanger tube material having such a shape, a brazed joint can be formed between the flat plate portion and the tip of the folded portion, and a support portion including the tip of the folded portion and the brazed joint can be formed on the tube material. Therefore, with this tube material, deformation of the heat exchanger during brazing heating can be easily suppressed.

[0083] (Outer wall material for heat exchanger flow channels) Furthermore, by forming the aluminum alloy plate, a heat exchanger channel wall material can be obtained that constitutes the outer wall of the channel for the heat transfer medium in the heat exchanger. The channel wall material may have, for example, a plurality of grooves and connecting parts that connect adjacent grooves. Two such channel wall materials can be superimposed so that a space is formed between the grooves of one channel wall material and the grooves of the other channel wall material, and the connecting parts of one channel wall material and the connecting parts of the other channel wall material are in contact, and then brazed, thereby forming a channel for the heat transfer medium in the space surrounded by the grooves. Moreover, by brazing in this manner, a support part including a connecting part and a brazed joint that joins the connecting parts can be formed between adjacent channel sections. Therefore, the channel wall material makes it easy to suppress deformation of the heat exchanger during brazing heating.

[0084] Furthermore, the channel wall material may have, for example, a flat plate portion and a peripheral edge portion provided around the flat plate portion, and the peripheral edge portion may be bent so as to protrude from the flat plate portion in one direction in the thickness direction of the flat plate portion. By overlapping a plurality of channel wall materials having such a shape so that their peripheral edges abut each other, a channel for a heat transfer medium can be formed between the channel wall materials. It is also preferable that a convex portion is formed on the flat plate portion of the channel wall material having such a shape, and that the convex portion is configured to abut the flat plate portion of the adjacent channel wall material. By brazing after overlapping such channel wall materials, a support portion including the convex portion and a brazed joint that joins the convex portion and the flat plate portion can be formed. [Examples]

[0085] (Example 1) An embodiment of the heat exchanger described above will be explained with reference to Figures 1 to 3. As shown in Figures 1 and 2, the heat exchanger 1 of this example has a first flow path 11, a plurality of flow path forming sections 2 arranged at intervals from each other, and a second flow path 12 formed between the flow path forming sections 2, and is configured so that the heat transfer medium in the first flow path 11 and the heat transfer medium in the second flow path 12 can exchange heat. As shown in Figures 2 and 3, the flow path forming section 2 has a first outer wall section 21 which constitutes the portion of the outer wall of the first flow path 11 that faces one of the two second flow paths 12 (12a, 12b) adjacent to the flow path forming section 2, a second outer wall section 22 which constitutes the portion of the outer wall of the first flow path 11 that faces the other second flow path 12b of the two second flow paths 12 adjacent to the flow path forming section 2, and a support section 23 which is arranged between both ends in the width direction of the flow path forming section 2 and is connected to both the first outer wall section 21 and the second outer wall section 22. The first outer wall portion 21 and the second outer wall portion 22 are made of an aluminum alloy plate 3 having a chemical composition containing Si: 1.5% to 3.0% by mass, Fe: 0.05% to 0.6% by mass, Mn: 0.3% to 2.0% by mass, with the remainder being Al and unavoidable impurities.

[0086] Specifically, the heat exchanger 1 in this example is a so-called parallel flow type heat exchanger, as shown in Figure 1, having a laminate 10 in which flow channel forming sections 2 and outer fins 13 are alternately stacked, and headers 14 positioned at both ends of the flow channel forming section 2 in the extending direction of the laminate 10. Although not shown in the figure, a brazed joint is formed between the flow channel forming section 2 and the header 14, and the flow channel forming section 2 and the header 14 are joined via the brazed joint.

[0087] As shown in Figure 3, the flow path forming section 2 in the heat exchanger 1 of this example has a flattened tube 24 and inner fins 25 arranged inside the flattened tube 24. The flattened tube 24 has an oval cross-sectional shape in a cross section perpendicular to its extending direction. A first flow path 11 is formed inside the flattened tube 24. The flattened tube 24 in this example is made of, for example, a single aluminum alloy plate 3, and the end faces of the aluminum alloy plates 3 are joined together via brazing 241.

[0088] As shown in Figure 2, a second flow path 12 is formed between adjacent flattened tubes 24 in the heat exchanger 1. Outer fins 13 are also arranged in the second flow path 12. The outer fins 13 in this example are corrugated fins having a fin top portion 131 that abuts against the flow path forming portion 2 and a fin intermediate portion 132 that connects adjacent fin top portions 131. As shown in Figure 2, a brazed joint 133 is formed between the flattened tubes 24 and the fin top portions 131 of the outer fins 13, and the flattened tubes 24 and the outer fins 13 are joined via the brazed joint.

[0089] As shown in Figures 2 and 3, the first outer wall portion 21 of the flow path forming section 2 in the heat exchanger 1 of this example is composed of the portion of the outer wall of each flat pipe 24 that faces one of the two second flow paths 12 (12a, 12b) facing the flat pipe 24, namely the second flow path 12a. The second outer wall portion 22 of the flow path forming section 2 is composed of the portion of the outer wall of each flat pipe 24 that faces the other of the two second flow paths 12 that face the flat pipe 24, namely the second flow path 12b.

[0090] As shown in Figure 3, the inner fin 25 in this example is a corrugated fin having a first fin top 251 that abuts against the first outer wall 21, a second fin top 252 that abuts against the second outer wall 22, and a fin intermediate portion 253 that connects the first fin top 251 and the second fin top 252. The first fin top 251 is joined to the first outer wall 21 via a brazing joint 254. Similarly, the second fin top 252 is joined to the second outer wall 22 via a brazing joint 255. The fin height of the inner fin 25, that is, the height from the first fin top 251 to the second fin top 252, can be appropriately set from a range of, for example, 1 mm to 50 mm. In addition, the fin pitch of the inner fin 25, that is, the distance from any first fin top 251 to the first fin top 251 located next to that first fin top 251, can be appropriately set from a range of, for example, 1 mm to 50 mm.

[0091] In this example, the inner fin 25 is connected to both the first outer wall portion 21 and the second outer wall portion 22 via brazed joints 254 and 255. Therefore, the support portion 23 of the flow path forming portion 2 includes the inner fin 25, the brazed joint 254 that joins the inner fin 25 to the first outer wall portion 21, and the brazed joint 255 that joins the inner fin 25 to the second outer wall portion 22. The flow path forming portion 2 in this example can be obtained, for example, by placing the inner fin 25 inside the cylinder of a tubularly bent aluminum alloy plate 3, and then brazing the aluminum alloy plate 3 and the inner fin 25 together.

[0092] The flow path forming section 2 of the heat exchanger 1 in this example has a first outer wall section 21 and a second outer wall section 22 made of aluminum alloy plate 3. Since the aluminum alloy plate 3 is composed of a single layer of aluminum alloy having the specific chemical composition described above, molten metal having the same chemical composition as the original aluminum alloy plate 3 can be easily obtained by melting the scraps of aluminum alloy plate 3 generated during the manufacturing process of the heat exchanger 1. Furthermore, since the first outer wall section 21 and the second outer wall section 22 are components with a high mass ratio within the heat exchanger 1, constructing the first outer wall section 21 and the second outer wall section 22 from aluminum alloy plate 3 makes it easy to reduce the environmental burden during the manufacturing process of the heat exchanger 1.

[0093] Furthermore, the flow channel forming section 2 has an inner fin 25 as a support section 23, which is positioned between its two ends in the width direction and joined to both the first outer wall section 21 and the second outer wall section 22. By providing the support section 23 between the two ends in the width direction of the flow channel forming section 2 in this way, the rigidity of the flow channel forming section 2 can be increased. As a result, deformation of the first outer wall section 21 and the second outer wall section 22 during brazing is suppressed, and the state in which the first outer wall section 21 and the second outer wall section 22 are in contact can be easily maintained during brazing heating.

[0094] Furthermore, the aluminum alloy plate 3 that constitutes the flattened tube 24 in the flow channel forming section 2 has the aforementioned specific chemical components, and therefore can generate a small amount of molten material when heated. Consequently, the molten material generated from the aluminum alloy plate 3 can be used to easily form brazed joints between the components of the heat exchanger 1.

[0095] Furthermore, the heat exchanger 1 has outer fins 13 provided in the second flow path 12, and the outer fins 13 are joined to the first outer wall portion 21 and the second outer wall portion 22 by brazing 133. By providing the outer fins 13 in the second flow path 12 in this way, the spacing between adjacent flow path forming portions 2 is more easily maintained. As a result, deformation of the flow path forming portions 2 during brazing can be more easily suppressed. In addition, by providing the outer fins 13 in the second flow path 12, the heat exchange efficiency of the heat exchanger 1 can be further improved.

[0096] As described above, the heat exchanger 1 in this example can reduce the environmental burden during the manufacturing process, suppress deformation during brazing heating, and easily form brazed joints between components.

[0097] (Example 2) In this example, an example of another embodiment of the flow path forming section will be described. In addition, among the reference numerals used in this embodiment and subsequent embodiments, the same reference numerals used in previously described embodiments will represent the same components as those in the previously described embodiments unless otherwise specified. Specifically, the heat exchanger 102 in this example is a so-called parallel flow type heat exchanger having a laminate 10 in which flow path forming sections 202 and outer fins 13 are alternately stacked, and headers (not shown) arranged at both ends in the longitudinal direction of the flow path forming sections 202 in the laminate 10.

[0098] The channel forming section 202 in this example is made of a single aluminum alloy plate 3 and has a substantially B-shaped cross-section in a cross-section perpendicular to the direction of extension. More specifically, the channel forming section 202 is formed by folding both ends of the aluminum alloy plate 3 in the width direction toward the center, and has a flat plate portion 26 originating from the central part of the aluminum alloy plate 3 in the width direction, and two folded portions 27 connected to the flat plate portion 26 at both ends of the channel forming section 202 in the width direction.

[0099] The tip 271 of the folded portion 27 abuts against the flat plate portion 26 at the center in the width direction of the flow channel forming portion 202, and a brazed joint 272 is formed between the tip 271 of the folded portion 27 and the flat plate portion 26. Furthermore, the space enclosed by the flat plate portion 26 and the folded portion 27 in the flow channel forming portion 202 constitutes the first flow channel 11. The flow channel forming portion 202 in this example can be obtained, for example, by forming the folded portion 27 by folding both ends in the width direction of the aluminum alloy plate 3 toward the center, and then brazing the tip 271 of the folded portion 27 to the flat plate portion 26.

[0100] A second flow channel 12 is formed between adjacent flow channel forming sections 202 in the heat exchanger 102. An outer fin 13 is also arranged in the second flow channel 12. The outer fin 13 is joined to the flow channel forming section 202 via brazing (not shown).

[0101] In this example, the first outer wall portion 21 of the flow path forming portion 202 in the heat exchanger 102 is composed of folded portions 27 of each flow path forming portion 202, and the second outer wall portion 22 is composed of a flat plate portion 26. Furthermore, the support portion of the flow path forming portion 202 includes a brazed joint 262 that joins the tip 271 of the folded portion 27 and the flat plate portion 26, and is located in the center in the width direction of the flow path forming portion 202. The configuration of other parts of the heat exchanger 102 in this example is the same as the configuration of the corresponding parts in the heat exchanger 1 of Embodiment 1.

[0102] The heat exchanger 102 in this example can achieve the same effects as the heat exchanger 1 in Example 1.

[0103] (Example 3) In this example, another example of the flow channel forming section will be described. The heat exchanger 103 in this example is a so-called parallel flow type heat exchanger, as shown in Figure 5, having a laminate 10 in which flow channel forming sections 203 and outer fins 13 are alternately stacked, and headers (not shown) arranged at both ends in the extending direction of the flow channel forming sections 203 in the laminate 10.

[0104] In this example, the flow channel forming section 203 consists of a space enclosed by a first outer wall section 21 and a second outer wall section 22, and has a plurality of first flow channels 11 arranged at intervals in the width direction of the flow channel forming section 203. Support sections 23 are provided between adjacent first outer wall sections 21 and between adjacent second outer wall sections 22.

[0105] As shown in Figure 6, the channel forming section 203 is composed of two aluminum alloy plates 303 (303a, 303b) each having a plurality of grooves 31 and connecting portions 32 that connect adjacent grooves 31. The aluminum alloy plates 303 constituting the channel forming section 203 have the specific chemical composition described above. As shown in Figure 5, the channel forming section 203 in this example can be obtained, for example, by overlapping two aluminum alloy plates 303 so that the grooves 31 face each other, and then joining the connecting portions 32 together via brazing (not shown).

[0106] A second flow channel 12 is formed between adjacent flow channel forming sections 203 in the heat exchanger 103. An outer fin 13 is also arranged in the second flow channel 12. The outer fin 13 is joined to the flow channel forming section 203 via brazing (not shown).

[0107] In this example, the first outer wall portion 21 of the flow path forming portion 203 in the heat exchanger 103 is made up of a groove portion 31 of one of the two aluminum alloy plates 303 (303a, 303b) that make up the flow path forming portion 203. The second outer wall portion 22 of the flow path forming portion 203 is made up of a groove portion 31 of the other aluminum alloy plate 303b that makes up the flow path forming portion 203. The support portion 23 of the flow path forming portion 203 includes a connecting portion 32 of the two aluminum alloy plates 303 and a brazed joint that joins the connecting portions 32 together, and is located between both ends of the flow path forming portion 203 in the width direction. The configuration of the other parts of the heat exchanger 103 in this example is the same as the configuration of the corresponding parts in the heat exchanger 103 of Embodiment 1.

[0108] The heat exchanger 103 in this example can achieve the same effects as the heat exchanger 1 in Example 1.

[0109] (Example 4) In this example, an example of a plate-type heat exchanger will be described. As shown in Figure 7, the heat exchanger 104 in this example has a plurality of flow channel forming sections 204, each comprising two plates 28 (28a, 28b) made of aluminum alloy plates 3 having the specific chemical composition, and a first fin 15 interposed between these plates 28, as well as a second fin 16. The flow channel forming sections 204 and the second fin 16 are stacked alternately, making it a so-called plate-type heat exchanger.

[0110] The flow channel forming section 204 in this example has two plates 28: a first plate 28a and a second plate 28b. The first flow channel 11 of the flow channel forming section 204 is composed of a space enclosed by the first plate 28a and the second plate 28b. As shown in Figure 8, the plate 28 is composed of an aluminum alloy plate 304 having a flat plate portion 281 and a peripheral edge portion 282 provided around the flat plate portion 281. The peripheral edge portion 282 of the aluminum alloy plate 304 is bent so as to protrude from the flat plate portion 281 in one direction in the thickness direction of the flat plate portion 281. Also, as shown in Figure 7, the peripheral edge portion 282 of the first plate 28a and the peripheral edge portion 282 of the second plate 28b are joined via a brazing joint 283.

[0111] In this example, the first fin 15 is a corrugated fin having a first fin top 151 that abuts against the flat portion 281 of the first plate 28a, a second fin top 152 that abuts against the flat portion 281 of the second plate 28b, and a fin intermediate portion (not shown) connecting the first fin top 151 and the second fin top 152. The first fin top 151 is joined to the flat portion 281 of the first plate 28a via a brazing joint 153. Similarly, the second fin top 152 is joined to the flat portion 281 of the second plate 28b via a brazing joint 154.

[0112] The flow channel forming portion 204 in this example can be obtained, for example, by brazing the peripheral edge portion 282 of the first plate 28a and the peripheral edge portion 282 of the second plate 28b while the first fin 15 is sandwiched between the flat plate portion 281 of the first plate 28a and the flat plate portion 281 of the second plate 28b.

[0113] In the heat exchanger 104 of this example, the peripheral edge 282 of the second plate 28b of each flow path forming section 204 is joined to the peripheral edge 282 of the first plate 28a of the adjacent flow path forming section 204 via a brazing joint 284. The space enclosed by the second plate 28b of each flow path forming section 204 and the first plate 28a of the adjacent flow path forming section 204 constitutes the second flow path 12.

[0114] The second channel 12 is equipped with a second fin 16, which is a corrugated fin having the same shape as the first fin 15. A brazed joint 162 is formed between the channel forming portion 204 and the fin top portion 161 of the second fin 16, and the channel forming portion 204 and the second fin 16 are joined via the brazed joint 162.

[0115] In this example, the first outer wall portion 21 of the flow path forming portion 204 in the heat exchanger 104 includes the flat plate portion 281 of the first plate 28a. The second outer wall portion 22 of the flow path forming portion 204 also includes the flat plate portion 281 of the second plate 28b. The support portion 23 of the flow path forming portion 204 includes the first fin 15, a brazed joint 153 that joins the first fin 15 to the flat plate portion 281 of the first plate 28a, and a brazed joint 154 that joins the first fin 15 to the flat plate portion 281 of the second plate 28b.

[0116] The heat exchanger 104 in this example can achieve the same effects as the heat exchanger 1 in Example 1.

[0117] (Experimental Example 1) In this example, we present an example of a mini-core test specimen 105 having the shape shown in Figure 9, which was prepared and its brazing properties evaluated. The mini-core test specimen 105 has a flow channel forming section 205 comprising a first outer wall section 21, a second outer wall section 22, and an inner fin 25 as a support section 23, and outer fins 13 joined to the outer surface of the first outer wall section 21 and the outer surface of the second outer wall section 22 in the flow channel forming section 205, respectively.

[0118] The channel forming section 205 in this example has a cylindrical shape consisting of two aluminum alloy plates 305 (305a, 305b) having the specific chemical composition described above. The first outer wall portion 21 of the channel forming section 205 is provided on one of the two aluminum alloy plates 305a, and the second outer wall portion 22 is provided on the other aluminum alloy plate 305b.

[0119] The aluminum alloy plate 305 has a flat portion 33 located in the center in its width direction, and side ends 34 located at both ends in the width direction and connected to the flat portion 33. The side ends 34 are bent so as to protrude to one side in the thickness direction of the flat portion 33. In addition, the side end 34 of one of the two aluminum alloy plates 305a and the side end 34 of the other aluminum alloy plate 305b are joined via brazing (not shown).

[0120] The inner fin 25 is positioned between the first outer wall portion 21 and the second outer wall portion 22. In this example, the inner fin 25 is a corrugated fin made of an aluminum alloy plate having the specific chemical composition described above, and has a first fin top portion 251 that abuts against the first outer wall portion 21 and a second fin top portion 252 that abuts against the second outer wall portion 22. The first fin top portion 251 is joined to the first outer wall portion 21 via brazing (not shown). The second fin top portion 252 is joined to the second outer wall portion 22 via brazing (not shown).

[0121] Furthermore, the outer fin 13 in this example is a corrugated fin made of an aluminum alloy plate having the specific chemical components mentioned above, and the fin top portion 131 of the outer fin 13 is joined to either the first outer wall portion 21 or the second outer wall portion 22 via brazing 133.

[0122] Table 1 shows the aluminum alloy plates A1 to A7 used to prepare the mini-core test specimen 105. The method for preparing these aluminum alloy plates is as follows, for example.

[0123] [Aluminum alloy sheets A1 and A5] Aluminum alloy sheets A1 and A5 are obtained by producing cast sheets using a continuous casting method, and then rolling the cast sheets. Specifically, first, cast sheets with the chemical composition shown in Table 1 are produced using a twin-roll continuous casting and rolling method. The temperature of the molten metal during casting can be appropriately set from, for example, within the range of 650°C to 800°C. The casting speed can also be appropriately set from, for example, within the range of 0.5 mm / min to 2.0 mm / min. The thickness of the cast sheet is not particularly limited, but is, for example, 6 mm.

[0124] Subsequently, rolling and heat treatment are carried out in appropriate combinations according to the desired thickness and temper. For example, to obtain an aluminum alloy sheet with a thickness of 0.20 mm and tempered to H14 material, a cast sheet is cold-rolled to produce a rolled sheet with a thickness of 0.250 mm. Next, the rolled sheet is held at a temperature of 370°C for 3 hours for intermediate annealing. Then, the rolled sheet after intermediate annealing is further cold-rolled to a thickness of 0.200 mm. By doing so, aluminum alloy sheets A1 and A5 having the chemical composition, thickness, and temper shown in Table 1 can be obtained. In Table 1, the continuous casting method is abbreviated as "CC". Also, "Bal." in Table 1 is a symbol indicating the remainder.

[0125] [Aluminum alloy sheets A2-A4 and A6-A7] Aluminum alloy sheets A2-A4 and A6-A7 are obtained by producing ingots by DC casting and then rolling the ingots. Specifically, first, ingots with the chemical composition shown in Table 1 are produced by DC casting. After homogenization treatment by holding these ingots at a temperature of 500°C for 8 hours, hot rolling is performed to produce rolled sheets with a thickness of 3 mm. The initial temperature of the ingot in the hot rolling process can be, for example, 480°C. Note that the holding temperature and holding time in the homogenization treatment are not limited to the above-described configuration. Furthermore, hot rolling can also be performed without homogenization treatment.

[0126] Subsequently, the rolled sheet obtained by hot rolling is subjected to rolling and heat treatment in an appropriate combination according to the desired thickness and temper. For example, to obtain an aluminum alloy sheet with a thickness of 0.20 mm and tempered to H14 material, the rolled sheet is cold-rolled to a thickness of 0.250 mm. Next, the rolled sheet is held at a temperature of 370°C for 3 hours for intermediate annealing. Then, the rolled sheet after intermediate annealing is further cold-rolled to a thickness of 0.200 mm. By doing so, aluminum alloy sheets A2-A4 and A6-A7 having the chemical composition, thickness, and temper shown in Table 1 can be obtained. Note that in Table 1, DC casting is abbreviated as "DC".

[0127] [Method for preparing minicore test specimen 105] To prepare the mini-core test specimen 105, first, the components of the mini-core test specimen 105 are made by press-forming an aluminum alloy plate. Next, these components are degreased using acetone, and then flux is applied to the surface of the components. After that, the components made of aluminum alloy plates are assembled in the combinations shown in Table 2 to create an assembly. The assembly thus obtained is compressed in the stacking direction between the outer fin 13 and the flow channel forming portion 205, and brazed by heating under conditions such that the time required to reach 575°C from 450°C is between 4 minutes and 15 minutes, and the time required to reach 615°C from 575°C is between 5 minutes and 40 minutes. As a result, test specimens S1 to S8 shown in Table 2 can be obtained.

[0128] Note that test specimens R1 to R4 shown in Table 2 are for comparison with test specimens S1 to S8. Test specimens R1 to R4 have the same configuration as test specimens S1 to S8, except that they do not have inner fins 25. The method for manufacturing test specimens R1 to R4 is the same as the method for manufacturing test specimens S1 to S8, except that the inner fins 25 are not placed between the first outer wall portion 21 and the second outer wall portion 22.

[0129] [Evaluation of brazing properties] The method for evaluating brazing properties using the mini-core test specimen 105 is as follows. First, the inner fin 25 is removed from the mini-core test specimen 105 after brazing, and the length of the fillet of the brazed joint formed between the first outer wall portion 21 and the inner fin 25 and the length of the fillet of the brazed joint formed between the second outer wall portion 22 and the inner fin 25 are measured.

[0130] Then, the ratio of the length of the fillet actually formed to the length of the fillet when all the fin tops 251 and 252 of the inner fin 25 are joined to the first outer wall portion 21 and the second outer wall portion 22 is calculated. This ratio is expressed as a percentage and is taken as the joining ratio of the inner fin 25. Specifically, the length of the fillet when all the fin tops 251 and 252 of the inner fin 25 are joined to the first outer wall portion 21 and the second outer wall portion 22 is obtained by multiplying the number of fin tops 251 and 252 of the inner fin 25 by the length of the inner fin 25 in the extending direction.

[0131] Furthermore, the outer fin 13 is removed from the brazed mini-core test specimen 105, and the fillet length of the brazed joint 133 formed between the first outer wall portion 21 and the outer fin 13 and the fillet length of the brazed joint (not shown) formed between the second outer wall portion 22 and the outer fin 13 are measured. Then, the bonding ratio of the outer fin 13 is calculated using the same method as the method for calculating the bonding ratio of the inner fin 25.

[0132] In Table 2, the "Inner Fin Bonding Rate" and "Outer Fin Bonding Rate" columns are marked with the symbol "A" if the bonding rate is 90% or higher, "B" if it is 50% or higher but less than 90%, and "C" if it is less than 50%.

[0133] [Table 1]

[0134] [Table 2]

[0135] As shown in Tables 1 and 2, the first outer wall portion 21 and the second outer wall portion 22 of test specimens S1 to S8 are both made of aluminum alloy plate 305 having the specific chemical composition described above. Furthermore, these test specimens have inner fins 25 as support portions 23. As a result, deformation during brazing is suppressed in these test specimens, and brazed joints can be easily formed at any position between the inner fins 25 and the flow channel forming portion 205, and between the outer fins 13 and the flow channel forming portion 205.

[0136] In contrast, since test specimens R1 to R4 do not have inner fins 25 as support parts 23, the flow channel forming part 205 deforms easily during brazing. As a result, the tops of the outer fins 13 separate from the flow channel forming part 205 during brazing, making it difficult to form a brazed joint between the flow channel forming part 205 and the outer fins 13.

[0137] (Experimental Example 2) In this example, we present an example of evaluating the corrosion resistance of a mini-core test specimen 105 having the shape shown in Figure 9. The aluminum alloy plates A8 to A10 used to prepare the mini-core test specimen 105 in this example have the chemical composition and thickness shown in Table 3. The method for preparing aluminum alloy plates A8 to A10 is the same as the method for preparing aluminum alloy plates A1 to A7 in Experimental Example 1, except that the chemical composition and thickness during casting were changed as shown in Table 3.

[0138] The method for fabricating the mini-core test specimen 105 in this example is the same as the method for fabricating the mini-core test specimen 105 in Experimental Example 1, except that the components of the mini-core test specimen 105 were fabricated using aluminum alloy plates A8 to A10, and these components were assembled in the combinations shown in Table 4.

[0139] [Measurement of natural electrode potential] Table 4 shows the natural electrode potential of the outer fin 13, the natural electrode potential of the outer surface of the first outer wall portion 21, and the natural electrode potential of the fillet of the brazed joint formed between the outer fin 13 and the first outer wall portion 21 in the mini-core test specimen 105 (test specimens S9-S10) of this example. The method for measuring these natural electrode potentials is as follows. First, the inner fin 25, the second outer wall portion 22, and the outer fin 13 joined to the second outer wall portion 22 are removed from the mini-core test specimen 105. Next, a test specimen is prepared by cutting the first outer wall portion 21 and the outer fin 13 joined to it to an appropriate size. Then, the portion of the test specimen other than the potential measurement area M of the natural electrode potential is covered with sealant.

[0140] Subsequently, the natural electrode potential of the potential measurement region M is measured as follows. The measuring device 4 shown in Figure 10 is used to measure the natural electrode potential. The measuring device 4 includes a first container 41 for immersing the test piece T in a solution, a second container 42 for immersing the reference electrode 44 in a solution, a salt bridge 43 for electrically connecting the solution in the first container 41 and the solution in the second container 42, and an electrometer 54 for measuring and recording the potential of the potential measurement region M relative to the reference electrode 44. In Figure 10, the shape of the test piece T is schematically shown.

[0141] The measurement of the natural electrode potential is performed as follows: First, a 5% NaCl aqueous solution, whose pH has been adjusted to 3 using acetic acid, is prepared in the first container 41, and a saturated NaCl aqueous solution is prepared in the second container 42. Then, the solution in the first container 41 and the solution in the second container 42 are electrically connected via a salt bridge 43. The temperature of each solution is set to room temperature.

[0142] Next, the test specimen T and the reference electrode 44 are electrically connected to the electrometer 54. For example, a saturated calomel electrode (so-called SCE) can be used as the reference electrode 44.

[0143] In this state, while stirring the solution in the first container 41, the potential measurement region M of the test piece T is immersed in the solution, and at the same time, the reference electrode 44 is immersed in the saturated NaCl aqueous solution in the second container 42. This allows the natural electrode potential (unit: mV vs SCE) of the potential measurement region M, with the reference electrode 44 as the reference, to be measured. The arithmetic mean of the natural electrode potentials from 20 hours to 24 hours after the start of measurement is then taken as the natural electrode potential of the potential measurement region M.

[0144] [Evaluation of corrosion resistance] The method for evaluating the corrosion resistance of the mini-core test specimen 105 is as follows. First, a SWAAT test is performed according to the method compliant with ASTM-G85-A3. The SWAAT test period is 500 hours. After the test, the mini-core test specimen 105 is visually inspected to determine whether or not the outer fin 13 has peeled off and whether or not through holes have formed in the channel forming section 205. If the outer fin 13 has not peeled off and no through holes have formed in the channel forming section 205 after the SWAAT test, the corrosion resistance is judged to be good, and "Good" is written in the "Corrosion Resistance" column of Table 5. If at least one of the above occurs after the SWAAT test, such as peeling of the outer fin 13 or the formation of through holes, the corrosion resistance is judged to be insufficient, and "Poor" is written in the "Corrosion Resistance" column of Table 5.

[0145] [Table 3]

[0146] [Table 4]

[0147] [Table 5]

[0148] As shown in Tables 3 and 4, the first outer wall portion 21 and the second outer wall portion 22 in test specimen S9 are made of aluminum alloy plate A8 containing Cu: 0.1% to 0.8% by mass and Zn: 1.0% by mass or less. By joining the first outer wall portion 21 and the second outer wall portion 22, which are made of such aluminum alloy plate, to the outer fin 13, as shown in Table 4, the natural electrode potential of the outer fin 13 can be made lower than the natural electrode potential of the first outer wall portion 21, the natural electrode potential of the second outer wall portion 22, and the natural electrode potential of the fillet of the brazed joint joining these outer walls to the outer fin 13. In a heat exchanger having such a natural electrode potential, as shown in Table 5, the outer fin 13 functions as a sacrificial anode for the first outer wall portion 21, the second outer wall portion 22, and the brazed joint, so that peeling of the outer fin 13 and the formation of through holes in the first outer wall portion 21 and the second outer wall portion 22 can be suppressed over a long period of time.

[0149] In contrast, as shown in Tables 3 and 4, the first outer wall portion 21 and the second outer wall portion 22 in test specimen S10 do not contain Cu, but have a relatively high Zn content. Therefore, in test specimen S10, as shown in Table 4, the natural electrode potential of the fillet of the brazed joint joining the outer wall portion and the outer fin 13 is lower than the natural electrode potential of the first outer wall portion 21, the natural electrode potential of the second outer wall portion 22, and the natural electrode potential of the outer fin 13. As a result, as shown in Table 5, the outer fin 13 is more likely to peel off prematurely. Furthermore, the peeling off of the outer fin 13 makes it easier for through holes to form prematurely in the first outer wall portion 21 and the second outer wall portion 22.

[0150] Although embodiments of the heat exchanger and its manufacturing method have been described above based on the examples and experimental cases, the specific embodiments of the heat exchanger and its manufacturing method according to the present invention are not limited to those of the examples, and the configuration can be modified as appropriate without impairing the spirit of the present invention.

[0151] For example, in Example 1, an example was shown in which the flattened tube of the flow channel forming section was made from a single aluminum alloy plate. However, the flattened tube can also be constructed by joining two aluminum alloy plates so that a space is formed inside them. Furthermore, in Example 1, an example was shown in which an inner fin was provided as a support part. However, a support part can also be formed by making a part of the first outer wall and / or the second outer wall of the flattened tube protrude toward the other outer wall and joining them to the other outer wall via brazing.

[0152] In addition, the heat exchanger may take the following forms, for example: [1] to [8].

[0153] [1] A heat exchanger having a first flow path, a plurality of flow path forming sections arranged at intervals from each other, and a second flow path formed between the flow path forming sections, wherein a heat transfer medium in the first flow path and a heat transfer medium in the second flow path are configured to perform heat exchange, The aforementioned flow channel forming section is The outer wall portion of the first channel, which constitutes the portion of the first channel facing one of the two second channels adjacent to the channel forming portion, The outer wall portion of the first channel, which is the portion of the second channel that faces the other of the two second channels adjacent to the channel forming portion, It has a support portion that is positioned between both ends in the width direction of the flow channel forming portion and is connected to both the first outer wall portion and the second outer wall portion, A heat exchanger in which the first outer wall portion and the second outer wall portion are made of an aluminum alloy plate having a chemical composition containing Si: 1.5% to 3.0% by mass, Fe: 0.05% to 0.6% by mass, Mn: 0.3% to 2.0% by mass, with the remainder being Al and unavoidable impurities.

[0154] [2] The heat exchanger according to [1], wherein at least one of the first outer wall portion and the second outer wall portion and the support portion are made of a common aluminum alloy plate. [3] The heat exchanger according to [1], wherein the support portion is made of an aluminum material different from the aluminum alloy plates that constitute the first outer wall portion and the second outer wall portion, and the support portion is joined to the first outer wall portion and the second outer wall portion by brazing. [4] The heat exchanger according to [3], wherein the support portion is an inner fin.

[0155] [5] The heat exchanger according to any one of [1] to [4], wherein the heat exchanger has outer fins provided in the second flow path, and the outer fins are joined to the first outer wall portion and the second outer wall portion by brazing. [6] The heat exchanger according to [5], wherein the natural electrode potential of the outer fin is less virtuous than the natural electrode potential of the first outer wall portion, the second outer wall portion, and the fillet of the brazed joint that joins these outer wall portions to the outer fin.

[0156] [7] The heat exchanger according to any one of [1] to [6], wherein the aluminum alloy plates constituting the first outer wall and the second outer wall further contain one or more elements selected from the group consisting of Cu: 0.8 mass% or less, Zn: 6.0 mass% or less, Mg: 0.2 mass% or less, Ti: 0.3 mass% or less, V: 0.3 mass% or less, Zr: 0.3 mass% or less, Cr: 0.3 mass% or less, Bi: 0.1 mass% or less, Ni: 0.6 mass% or less, Sn: 0.3 mass% or less, In: 0.1 mass% or less, Sr: 0.1 mass% or less, Na: 0.1 mass% or less, Sb: 0.3 mass% or less, and Ca: 0.5 mass% or less. [8] The heat exchanger according to any one of [1] to [7], wherein the aluminum alloy plates constituting the first outer wall and the second outer wall further contain Cu: 0.1% by mass or more and 0.8% by mass or less and Zn: more than 0% by mass and 1.0% by mass or less.

[0157] Furthermore, the method for manufacturing the heat exchanger may take the form described in [9] below, for example.

[0158] A method for manufacturing a heat exchanger as described in any one of [9], [1], to [8], The components of the heat exchanger, including the flow path forming section, are assembled to create an assembly. A method for manufacturing a heat exchanger, comprising heating the assembly and brazing it under conditions such that the time required to reach 575°C from 450°C is 4 minutes or more and 15 minutes or less, and the time required to reach 615°C from 575°C is 5 minutes or more and 40 minutes or less.

[0159] Furthermore, the aluminum alloy plate for forming the flow channel can take the following forms, for example:

[10] to

[12] .

[0160]

[10] A flow channel forming aluminum alloy plate used to form the outer wall of the flow channel of a heat transfer medium in a heat exchanger, An aluminum alloy plate for forming flow channels, having a chemical composition in which Si: 1.5% to 3.0% by mass, Fe: 0.05% to 0.6% by mass, Mn: 0.3% to 2.0% by mass, and further containing as an optional component one or more elements selected from the group consisting of Cu: 0.8% or less by mass, Zn: 6.0% or less by mass, Mg: 0.2% or less by mass, Ti: 0.3% or less by mass, V: 0.3% or less by mass, Zr: 0.3% or less by mass, Cr: 0.3% or less by mass, Bi: 0.1% or less by mass, Ni: 0.6% or less by mass, Sn: 0.3% or less by mass, In: 0.1% or less by mass, Sr: 0.1% or less by mass, Na: 0.1% or less by mass, Sb: 0.3% or less by mass, and Ca: 0.5% or less, with the remainder being Al and unavoidable impurities.

[0161]

[11] A flow channel forming aluminum alloy plate used to form the outer wall of the flow channel of a heat transfer medium in a heat exchanger, An aluminum alloy plate for forming flow channels, having a chemical composition in which Si: 1.5% to 3.0% by mass, Fe: 0.05% to 0.6% by mass, Mn: 0.3% to 2.0% by mass, Cu: 0.1% to 0.8% by mass, Zn: greater than 0% and 6.0% by mass, and further containing as an optional component one or more elements selected from the group consisting of Mg: 0.2% or less by mass, Ti: 0.3% or less by mass, V: 0.3% or less by mass, Zr: 0.3% or less by mass, Cr: 0.3% or less by mass, Bi: 0.1% or less by mass, Ni: 0.6% or less by mass, Sn: 0.3% or less by mass, In: 0.1% or less by mass, Sr: 0.1% or less by mass, Na: 0.1% or less by mass, Sb: 0.3% or less by mass, and Ca: 0.5% or less, with the remainder being Al and unavoidable impurities.

[0162]

[12] The aluminum alloy plate for forming flow channels according to

[11] , wherein the sum of the Cu content and Fe content in the aluminum alloy plate is greater than 0.65 mass%.

[0163] Furthermore, the tube material for the heat exchanger may take the following forms

[13] to

[14] .

[0164] A tube material for a heat exchanger, composed of an aluminum alloy plate for flow channel formation as described in any one of

[13] ,

[10] , to

[12] .

[14] The tube material for a heat exchanger according to

[13] , wherein the tube material has a flat portion derived from the central part in the width direction of the aluminum alloy plate and folded portions obtained by folding both ends of the aluminum alloy plate in the width direction toward the central part, and the tip of the folded portion faces the flat portion.

[0165] Furthermore, the outer wall material of the flow path for the heat exchanger may take the following forms

[15] to

[16] .

[0166] A heat exchanger channel outer wall material composed of an aluminum alloy plate for forming channel described in any one of

[15] ,

[10] to

[12] , wherein the channel outer wall material has a plurality of grooves and connecting parts that connect adjacent grooves. A heat exchanger channel outer wall material comprising an aluminum alloy plate for forming channel described in any one of

[16] ,

[10] to

[12] , wherein the channel outer wall material comprises a flat plate portion and a peripheral edge portion provided around the flat plate portion, and the peripheral edge portion is bent so as to protrude from the flat plate portion in one direction in the thickness direction of the flat plate portion. [Explanation of Symbols]

[0167] 1, 102~104 heat exchanger 11 First channel 12 Second flow path 2. 202-204 Flow channel forming section 21 First outer wall 22 Second outer wall section 23 Support part 3,303 Aluminum alloy plate

Claims

1. A heat exchanger comprising a first channel, a plurality of channel forming sections arranged at intervals from each other, and a second channel formed between the channel forming sections, configured such that a heat transfer medium in the first channel and a heat transfer medium in the second channel can exchange heat, The aforementioned flow channel forming section is The outer wall portion of the first channel, which constitutes the portion of the first channel facing one of the two second channels adjacent to the channel forming portion, The outer wall portion of the first channel, which is the portion of the second channel that faces the other of the two second channels adjacent to the channel forming portion, It has a support portion that is positioned between both ends in the width direction of the flow channel forming portion and is connected to both the first outer wall portion and the second outer wall portion, A heat exchanger in which the first outer wall portion and the second outer wall portion are made of an aluminum alloy plate having a chemical composition containing Si: 1.5% by mass or more and 3.0% by mass or less, Fe: 0.05% by mass or more and 0.6% by mass or less, Mn: 0.3% by mass or more and 2.0% by mass or less, with the remainder being Al and unavoidable impurities.

2. The heat exchanger according to claim 1, wherein at least one of the first outer wall portion and the second outer wall portion and the support portion are made of a common aluminum alloy plate.

3. The heat exchanger according to claim 1, wherein the support portion is made of an aluminum material different from the aluminum alloy plates constituting the first outer wall portion and the second outer wall portion, and the support portion is joined to the first outer wall portion and the second outer wall portion by brazing.

4. The heat exchanger according to claim 3, wherein the support portion is an inner fin.

5. The heat exchanger according to claim 1, wherein the heat exchanger has an outer fin provided in the second flow path, and the outer fin is joined to the first outer wall portion and the second outer wall portion by brazing.

6. The heat exchanger according to claim 5, wherein the natural electrode potential of the outer fin is less valuable than the natural electrode potential of the first outer wall portion, the second outer wall portion, and the fillet of the brazed joint that joins these outer wall portions to the outer fin.

7. The heat exchanger according to claim 1, wherein the aluminum alloy plates constituting the first outer wall portion and the second outer wall portion further contain one or more elements selected from the group consisting of Cu: 0.8 mass% or less, Zn: 6.0 mass% or less, Mg: 0.2 mass% or less, Ti: 0.3 mass% or less, V: 0.3 mass% or less, Zr: 0.3 mass% or less, Cr: 0.3 mass% or less, Bi: 0.1 mass% or less, Ni: 0.6 mass% or less, Sn: 0.3 mass% or less, In: 0.1 mass% or less, Sr: 0.1 mass% or less, Na: 0.1 mass% or less, Sb: 0.3 mass% or less, and Ca: 0.5 mass% or less.

8. The heat exchanger according to claim 1, wherein the aluminum alloy plates constituting the first outer wall portion and the second outer wall portion further contain Cu: 0.1% by mass or more and 0.8% by mass or less and Zn: more than 0% by mass and 1.0% by mass or less.

9. A method for manufacturing a heat exchanger according to any one of claims 1 to 8, The components of the heat exchanger, including the flow path forming section, are assembled to create an assembly. A method for manufacturing a heat exchanger, comprising heating the assembly and brazing it under conditions such that the time required to reach 575°C from 450°C is 4 minutes or more and 15 minutes or less, and the time required to reach 615°C from 575°C is 5 minutes or more and 40 minutes or less.

10. An aluminum alloy plate for forming flow channels, used to form the outer wall of the flow channel of a heat transfer medium in a heat exchanger, An aluminum alloy plate for forming flow channels has a chemical composition comprising Si: 1.5% to 3.0% by mass, Fe: 0.05% to 0.6% by mass, Mn: 0.3% to 2.0% by mass, and further containing as an optional component one or more elements selected from the group consisting of Cu: 0.8% or less by mass, Zn: 6.0% or less by mass, Mg: 0.2% or less by mass, Ti: 0.3% or less by mass, V: 0.3% or less by mass, Zr: 0.3% or less by mass, Cr: 0.3% or less by mass, Bi: 0.1% or less by mass, Ni: 0.6% or less by mass, Sn: 0.3% or less by mass, In: 0.1% or less by mass, Sr: 0.1% or less by mass, Na: 0.1% or less by mass, Sb: 0.3% or less by mass, and Ca: 0.5% or less, with the remainder being Al and unavoidable impurities.

11. An aluminum alloy plate for forming flow channels, used to form the outer wall of the flow channel of a heat transfer medium in a heat exchanger, Si: 1.5 mass% or more and 3.0 mass% or less, Fe: 0.05 mass% or more and 0.6 mass% or less, Mn: 0.3 mass% or more and 2.0 mass% or less, Cu: 0.1 mass% or more and 0.8 mass% or less, Zn: 0 Contains more than 6.0 mass% by mass, and further includes optional components: Mg: 0.2 mass% or less, Ti: 0.3 mass% or less, V: 0.3 mass% or less, Zr: 0.3 mass% or less, Cr: 0.3 mass% or less. Below is an aluminum alloy plate for forming flow channels, having a chemical composition containing one or more elements selected from the group consisting of Bi: 0.1% by mass or less, Ni: 0.6% by mass or less, Sn: 0.3% by mass or less, In: 0.1% by mass or less, Sr: 0.1% by mass or less, Na: 0.1% by mass or less, Sb: 0.3% by mass or less, and Ca: 0.5% by mass or less, with the remainder being Al and unavoidable impurities.

12. The aluminum alloy plate for forming flow channels according to claim 11, wherein the sum of the Cu content and Fe content in the aluminum alloy plate is greater than 0.65% by mass.

13. A tube material for a heat exchanger, comprising an aluminum alloy plate for forming flow channels as described in any one of claims 10 to 12.

14. The tube material for a heat exchanger according to claim 13, wherein the tube material has a flat portion derived from the central part in the width direction of the aluminum alloy plate and folded portions obtained by folding both ends of the aluminum alloy plate in the width direction toward the central part, and the tips of the folded portions face the flat portion.

15. A flow channel outer wall material for a heat exchanger, comprising an aluminum alloy plate for forming flow channels as described in any one of claims 10 to 12, wherein the flow channel outer wall material for a heat exchanger has a plurality of grooves and connecting portions that connect adjacent grooves.

16. A flow channel outer wall material for a heat exchanger, comprising an aluminum alloy plate for forming flow channels as described in any one of claims 10 to 12, wherein the material has a flat plate portion and a peripheral edge portion provided around the flat plate portion, and the peripheral edge portion is bent so as to protrude from the flat plate portion in one direction in the thickness direction of the flat plate portion.

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