Composite aluminum foil for fin and fin and heat exchanger adopting same

Abstract

The invention discloses a composite aluminum foil for a fin, the fin adopting the composite aluminum foil and a heat exchanger, the composite aluminum foil material comprises a core layer, the core layer is made of aluminum or aluminum alloy, and the core layer comprises a first side face and a second side face which are oppositely arranged in the thickness direction of the core layer; the composite layers are arranged on at least one of the first side face and the second side face, the composite layers comprise at least one first composite layer and at least one second composite layer, and the first composite layers and the second composite layers are adjacently arranged in the width direction of the core layer. The content of Si in the material of the first composite layer is smaller than or equal to 1.2%, and the content of Si in the material of the second composite layer is larger than or equal to 5% and smaller than or equal to 12%. The composite aluminum foil and the fin are beneficial to reducing intergranular corrosion and improving corrosion resistance, the fin is applied to a heat exchanger, the corrosion resistance of the heat exchanger is improved, and the service life of the heat exchanger is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchange, and particularly relates to a composite aluminum foil for fins, a fin and a heat exchanger using the same. Background Art

[0002] In related technologies, aluminum alloy heat exchangers have been widely used. The heat exchanger includes heat exchange tubes and fins, and the fins are welded to the heat exchange tubes to enhance heat exchange with air. The corrosion resistance of the fins not only affects the heat exchange performance of the heat exchanger, but also is related to the service life of the heat exchanger, and is an important index of the fin performance. Summary of the Invention

[0003] On the one hand, the present invention provides a composite aluminum foil for fins and a processing method thereof. Applying the composite aluminum foil to the fins is beneficial to reducing intergranular corrosion and improving corrosion resistance.

[0004] On the other hand, the present invention also provides a fin, which is beneficial to reducing intergranular corrosion and improving corrosion resistance.

[0005] On yet another hand, the present invention also provides a heat exchanger. Applying the fin to the heat exchanger improves the corrosion resistance of the heat exchanger and is beneficial to extending the service life of the heat exchanger.

[0006] According to an embodiment of the first aspect of the present invention, a composite aluminum foil for fins is provided. The composite aluminum foil material includes: A core layer, the material of the core layer is aluminum or aluminum alloy, and the core layer includes a first side surface and a second side surface that are oppositely arranged in the thickness direction of the core layer; A composite layer, the composite layer is provided on at least one of the first side surface and the second side surface. The composite layer includes at least one first composite layer and at least one second composite layer. The first composite layer and the second composite layer are adjacent to each other along the width direction of the core layer. By mass percentage, the Si content in the material of the first composite layer is less than or equal to 1.2%, and the Si content in the material of the second composite layer is greater than or equal to 5% and less than or equal to 12%.

[0007] In this embodiment, the composite aluminum foil material is provided with a composite layer outside the core layer. The composite layer includes at least one first composite layer and at least one second composite layer. The first composite layer and the second composite layer are arranged adjacent to each other along the width direction of the core layer. The Si content in the first composite layer is less than or equal to 1.2%, and the Si content in the second composite layer is greater than or equal to 5% and less than or equal to 12%. The Si content at the second composite layer being greater than or equal to 5% and less than or equal to 12% facilitates welding connection with other components. While the Si content in the first composite layer is less than or equal to 1.2%, when this composite aluminum foil is applied to fins, while enabling welding with other components, reducing the Si content in the composite aluminum foil material is beneficial for reducing intergranular corrosion and improving corrosion resistance.

[0008] According to an embodiment of another aspect of the present invention, a method for processing a composite aluminum foil for fins is provided, including the following steps: Provide an aluminum foil, and the aluminum foil forms a core layer by at least melting, casting, and surface cutting; Form a raw material for the first composite layer by at least melting, casting, hot rolling, and cutting, and the Si content in the first composite layer is less than or equal to 1.2%; Form a raw material for the second composite layer by at least melting, casting, hot rolling, and cutting, and the Si content in the second composite layer is greater than or equal to 5% and less than or equal to 12%; Place the raw material of the first composite layer on the core layer, place the raw material of the second composite layer on the core layer. The first composite layer and the second composite layer form a composite layer, and use hot cladding rolling to integrate the stacked core layer and the composite layer, thereby forming a rolled material; Cold roll, anneal, and cut the rolled material, and process it as needed to form a composite aluminum foil.

[0009] In this embodiment, a composite aluminum foil with good corrosion resistance can be obtained through this processing method. Applying this composite aluminum foil to fins is beneficial for improving the corrosion resistance and reliability of the fins.

[0010] The present invention further provides a fin. The fin material includes the above-mentioned composite aluminum foil. The fin includes a plurality of through holes or through grooves, and the plurality of through holes or through grooves are arranged at intervals along the length direction of the fin. Along the width direction of the fin, near the through holes or through grooves, the fin material includes the second composite layer, and away from the through holes or through grooves, the fin material includes the first composite layer.

[0011] In this embodiment, the fin material includes the above-mentioned composite aluminum foil. The fins are formed by processing the above-mentioned composite aluminum foil as required. The fins include through holes or through slots, and the fins are connected to other components through the through holes or through slots. In the width direction of the fins, near the through holes or through slots, the fin material includes a second composite layer, and the Si content in the second composite layer is greater than or equal to 5% and less than or equal to 12%, which facilitates the welding of the fins to other components. Away from the through holes or through slots, the fin material includes a first composite layer, and the Si content in the first composite layer is less than or equal to 1.2%. Thus, while realizing the welding of the fins to other components, the Si content in the fins is reduced, which is beneficial to reducing intergranular corrosion and improving the corrosion resistance of the fins.

[0012] According to an embodiment of another aspect of the present invention, a heat exchanger is provided. The heat exchanger includes a first pipe, a second pipe, and a plurality of heat exchange pipes. The first pipe and the second pipe are arranged at intervals. One end of the heat exchange pipe is connected to the first pipe, and the other end of the heat exchange pipe is connected to the second pipe to connect the first pipe and the second pipe. The heat exchanger further includes fins, and the fins are the above-mentioned fins. The heat exchange pipes are adaptively installed in the through holes or the through slots, and the heat exchange pipes and the fins are welded through the second composite layer.

[0013] For the heat exchanger according to this embodiment, the fins of the embodiment of the present application are adopted. The heat exchange pipes are adaptively installed in the through holes or through slots. At the connection between the fins and the heat exchange pipes near the through holes or through slots, the fin material includes a second composite layer, and the Si content in the second composite layer material is greater than or equal to 5% and less than or equal to 12% to realize the welded connection between the fins and the heat exchange pipes. Away from the connection between the fins and the heat exchange pipes, the fin material includes a first composite layer, and the Si content in the first composite layer is less than or equal to 1.2%. Thus, while realizing the welding between the fins and the heat exchange, the Si content in the fins is reduced, the probability of intergranular corrosion is reduced, the corrosion resistance of the fins is improved, and further the corrosion resistance of the heat exchange pipes connected to the fins is improved, and the overall corrosion resistance of the heat exchanger is improved, which is beneficial to improving the service life of the heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic structural diagram of a composite aluminum foil according to an embodiment of the present application; Figure 2 is a schematic structural diagram of another composite aluminum foil according to an embodiment of the present application; Figure 3 is a schematic structural diagram of still another composite aluminum foil according to an embodiment of the present application; Figure 4 is a schematic structural diagram of yet another composite aluminum foil according to an embodiment of the present application; Figure 5 is a schematic structural diagram of yet another composite aluminum foil according to an embodiment of the present application; Figure 6 is a schematic structural view of another composite aluminum foil according to an embodiment of the present application; Figure 7a is a schematic structural view of a fin for a heat exchanger according to an embodiment of the present application; Figure 7b is Figure 7a a schematic structural view of the fin material in Figure 8 is a schematic structural view of a heat exchanger according to an embodiment of the present application; Figure 9 is a schematic partial structural view of a heat exchanger according to an embodiment of the present application; Figure 10a is a schematic structural view of another fin for a heat exchanger according to an embodiment of the present application; Figure 10b is Figure 10a a schematic structural view of the fin material in Figure 11 is a schematic partial structural view of another heat exchanger according to an embodiment of the present application; Figure 12a is a schematic structural view of another fin for a heat exchanger according to an embodiment of the present application; Figure 12b is Figure 12a a schematic structural view of the fin material in.

[0015] Reference numerals: Fin 1, core layer 11, composite layer 12, first composite layer 121, second composite layer 122, first layer 1221, second layer 1222, third composite layer 123; Heat exchanger 100, heat exchange tube 2, first tube 3, second tube 4. Detailed implementation manners

[0016] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention. All other technical solutions obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0017] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0018] It should be understood that the term "and / or" used herein is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this text generally represents an "or" relationship between the preceding and following associated objects.

[0019] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or fixture referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0020] For the composite aluminum foil and fins of the embodiments of the present invention, in addition to corrosion resistance, in order to meet the strength and processing and manufacturing performance required for components such as composite aluminum foil and fins, it is necessary to design their elemental composition and content. Next, the elemental composition and addition amount of the aluminum alloy material included in the composite aluminum foil and fins of the embodiments of the present invention will be described. And in the embodiments of the present invention, unless otherwise specified, the content of the alloying elements in the aluminum alloy material of the embodiments of the present invention refers to the mass content.

[0021] A composite aluminum foil according to an embodiment of the present invention, as Figures 1-6 shown, includes: a core layer 11, the material of the core layer 11 is aluminum or aluminum alloy, wherein the aluminum of the core layer 11 is commercially pure aluminum, and the aluminum alloy of the core layer 11 can be anti-rust aluminum, aluminum-zinc alloy and other aluminum alloys. The core layer 11 includes a first side surface and a second side surface oppositely arranged in the thickness direction of the core layer 11; the thickness direction of the core layer 11 is Figures 1-6 the up-and-down direction in

[0022] a composite layer 12, the material of the composite layer 12 is aluminum alloy, and the composite layer 12 is provided on at least one of the first side surface and the second side surface, that is, as Figure 1 shown, a composite layer 12 can be provided only outside the first side surface of the core layer 11, or a composite layer 12 can be provided only outside the second side surface of the core layer 11, or as Figure 2 shown, composite layers 12 are provided outside both the first side surface and the second side surface of the core layer 11, that is, composite layers 12 are provided outside both the upper side surface and the upper side surface of the core layer 11.

[0023] As Figures 1-6As shown, the composite layer 12 includes at least one first composite layer 121 and at least one second composite layer 122. The first composite layer 121 and the second composite layer 122 are arranged adjacent to each other in the width direction of the core layer 11, and the width direction of the core layer 11 is Figures 1-6 the left-right direction in Figure 1 . Figure 2 . Figure 4 and Figure 6 As shown in, in the width direction along the core layer 11, the composite aluminum foil may have one first composite layer 121 and one second composite layer 122, and the first composite layer 121 and the second composite layer 122 are arranged adjacent to each other; or as Figure 5 shown in, in the width direction along the core layer 11 of the composite aluminum foil, one first composite layer 121, one second composite layer 122, and one first composite layer 121 are arranged; or, it may also be as Figure 3 shown in, in the width direction along the core layer 11, one first composite layer 121, one second composite layer 122, one first composite layer 121, and one second composite layer 122 are arranged, and the first composite layer 121 and the second composite layer 122 are arranged at intervals. It can be understood that multiple first composite layers 121 and second composite layers 122 can be set according to the needs of the heat exchanger structure to be applied, and no limitation is made here.

[0024] By mass percentage, the Si content in the material of the first composite layer 121 is less than or equal to 1.2%, and the Si content in the material of the second composite layer 122 is greater than or equal to 5% and less than or equal to 12%.

[0025] Specifically, the materials of the first composite layer 121 and the second composite layer 122 are aluminum alloys. The Si content in the material of the first composite layer 121 is less than or equal to 1.2%. Si is the main impurity element in the raw material of aluminum alloy, and Si exists in the form of solid solution in Al, which has a certain solid solution strengthening effect on Al. However, excessive Si will increase the probability of intergranular corrosion and reduce the corrosion resistance of the aluminum alloy. Therefore, in the composite layer material where the welding area does not need to be realized, controlling the Si element content to be less than or equal to 1.2% can avoid intergranular corrosion caused by Si diffusion when Si is excessive and improve the corrosion resistance of the composite aluminum foil.

[0026] The Si content in the material of the second composite layer 122 is greater than or equal to 5% and less than or equal to 12%, which facilitates welding with other components while ensuring the corrosion resistance of the material. According to the Al-Si alloy phase diagram, when the Si content rate is less than 5%, the liquid phase is insufficient and effective welding cannot be carried out. Therefore, a composite aluminum foil with a Si content greater than 5% in the second composite layer 122 is selected for bonding. When the Si content is greater than 12%, too much Si is likely to form intergranular corrosion and reduce corrosion resistance. Optionally, the welding method can be brazing.

[0027] The composite aluminum foil material in the embodiments of the present application includes a core layer 11 and a composite layer 12. The composite layer 12 includes an interleaved structure of a first composite layer 121 with a Si content less than or equal to 1.2% formed in the width direction of the core layer and a second composite layer 122 with a Si content greater than or equal to 5% and less than or equal to 12%. When applying this composite aluminum foil to the fin 1, the heat exchange tube 2 of the heat exchanger 100 is connected to the second composite layer 122 in the composite layer material of the fin 1 by welding. In the area far from the heat exchange tube 2, the composite layer 12 material of the fin 1 uses the first composite layer 121 with a Si content less than or equal to 1.2%. The Si content in the material is reduced at the position where welding is not required, so that the overall Si content in the fin can be reduced while realizing the welding of the fin 1 with other components. Since Si is an element that increases the potential of the aluminum alloy, the Si enriched at the grain boundaries will cause corrosion to occur along the grain boundaries. Intergranular corrosion is a highly destructive corrosion mode that will cause the material to lose strength and lead to fragmentation and pulverization. The composite aluminum foil in this embodiment reduces the Si content on the premise of being able to achieve welding, reduces the probability of intergranular corrosion occurring, improves the corrosion resistance of the composite aluminum foil, and improves the reliability of the material.

[0028] In some embodiments, by mass percentage, the Si content in the material of the first composite layer 121 is 0.3 - 1.2%.

[0029] The content of Si element in the first composite layer 121 is 0.3 - 1.2%. Specifically, for example, 0.4%, 0.5%, 0.6%, 0.65%, 0.8%, 1.0%, 1.05%, 1.1%. Si is the main impurity element in the aluminum alloy raw material. Si exists in a solid solution form in Al and has a certain solid solution strengthening effect on Al. Si is an element that increases the potential of the Al alloy, but excessive Si will increase the probability of intergranular corrosion occurring and reduce the corrosion resistance of the aluminum alloy. Therefore, in the material of the area where welding does not need to be realized, controlling the content of Si element to be greater than or equal to 0.3% and less than or equal to 1.2% can avoid intergranular corrosion caused by Si diffusion when Si is excessive and improve the corrosion resistance of the composite aluminum foil.

[0030] Furthermore, the first composite layer 121 also includes Mn: 0.01-2.5%, Fe: 0.01-0.5%, Zn: 0.02-3.0%, Cu: 0.01-0.8%, and the remainder is Al and inevitable impurity elements, wherein the individual content of the inevitable impurity elements does not exceed 0.15%, and the total content does not exceed 0.5%.

[0031] Among them, the addition of Mn elements can reduce the adverse effects of Si on the corrosion of aluminum alloys to a certain extent and improve corrosion resistance. The content of Cu element is 0.01-0.8%. From the Al-Cu binary phase diagram, the maximum solid solubility of Cu in Al is 5.65% at a high temperature of 548°C. As the temperature decreases, the equilibrium solid solubility decreases, about 0.45% at 300°C, and about 0.1% at room temperature. During the solidification and subsequent processing and welding of the alloy, due to the limited high-temperature residence time and the influence of solidification rate, Cu usually cannot reach a complete equilibrium state in Al, and it is difficult to form a second phase precipitation even in the case of slight supersaturation. Cu can increase the strength of the alloy and improve the corrosion potential of the composite aluminum foil. The amount of Cu element added in the material of this application does not exceed 0.8%.

[0032] In some embodiments, the Si content in the material of the second composite layer 122 is 5.0-12.0% by mass.

[0033] The content of Si element in the second composite layer 122 is 5.0-12.0%, specifically, for example, 5.5%, 6%, 6.5%, 7%, 8%, 9%, 9.5%, 10%, 11%, and 11.5%; the content of Si element in the second composite layer 122 is 5.0-12.0%, which can reduce intergranular corrosion and improve the corrosion resistance of the alloy aluminum foil when welding is achieved.

[0034] Furthermore, the second composite layer 122 also includes Mn: 0.01-2.5%, Fe: 0.01-0.5%, Zn: 0.02-3.0%, Cu: 0.01-0.8%, and the balance is Al and inevitable impurity elements, wherein the individual content of the inevitable impurity elements does not exceed 0.15%, and the total content does not exceed 0.5%.

[0035] Among them, the addition of Mn elements can reduce the adverse effects of Si on the corrosion of aluminum alloys to a certain extent and improve corrosion resistance. The content of Cu element is 0.01-0.8%. From the Al-Cu binary phase diagram, the maximum solid solubility of Cu in Al is 5.65% at a high temperature of 548°C. As the temperature decreases, the equilibrium solid solubility decreases, about 0.45% at 300°C, and about 0.1% at room temperature. During the solidification and subsequent processing and welding of the alloy, due to the limited high-temperature residence time and the influence of solidification rate, Cu usually cannot reach a complete equilibrium state in Al, and it is difficult to form a second phase precipitation even in the case of slight supersaturation. Cu can increase the strength of the alloy and improve the corrosion potential of the composite aluminum foil. The amount of Cu element added in the material of this application does not exceed 0.8%.

[0036] In some embodiments, the thickness of the composite layer 12 accounts for 6%-15% of the thickness of the composite aluminum foil.

[0037] Specifically, the composite aluminum foil comprises a core layer 11 and a composite layer 12. The thickness of the composite layer disposed on one side of the core layer 11 accounts for 6%-15% of the thickness of the composite aluminum foil, for example, 6%, 8%, 10%, 12%, 15%, etc. Composite layer 12 contains Si, which facilitates welding with other components. When the thickness of composite layer 12 accounts for less than 6% of the thickness of the composite aluminum foil, the solder is insufficient, and the welding quality cannot be guaranteed when the composite aluminum foil is welded with other components. When the thickness of composite layer 12 accounts for more than 15% of the thickness of the composite aluminum foil, the Si content in the composite layer is too high, which easily causes intergranular corrosion. Therefore, setting the thickness of composite layer 12 to 6%-15% of the thickness of the composite aluminum foil allows the composite aluminum foil, when used in fins, to be welded to heat exchange tubes or other components of different sizes, thereby improving the applicability of the fin 1 and ensuring the reliability of welding the composite aluminum foil with other components.

[0038] In some embodiments, in order to achieve welding of both the first side and the second side of the composite aluminum foil, a composite layer 12 is provided on the first side and the second side of the core layer 11. At this time, the total thickness of the composite layer 12 accounts for 12%-30% of the thickness of the composite aluminum foil, which facilitates better welding of other components connected to the composite aluminum foil.

[0039] In some embodiments, the core layer 11 in the composite aluminum foil is mainly composed of alloy elements in the following mass percentage (wt.%) ranges: Mn: 0.20-2.5%, Fe: 0.01-0.5%, Si: 0.3-1.2%, Zn: 1.0-3.0%, Cu: 0.01-0.8%, Ti: 0.001-0.2%, and the balance is Al and unavoidable impurity elements. The individual content of the unavoidable impurity elements does not exceed 0.05%, and the total content does not exceed 0.3%.

[0040] Among them, the core layer 11 is the main material of the composite aluminum foil, and the core layer 11 can be an Al-Mn alloy. In the Al-Mn alloy, a certain amount of Mn can reduce the adverse effect of Si on the corrosion of the aluminum alloy to a certain extent; the solid solubility of Fe in Al is very low. When Fe exists alone in Al, it usually exists in the form of intermetallic compounds such as Al3Fe, which has a good strengthening effect on the alloy. However, due to the large difference in corrosion potential between Al3Fe and the Al matrix, pitting corrosion is easily induced. Taking into account the purity grade of the electrolytic aluminum raw materials and their influence on the corrosion resistance and extrusion properties of the alloy, the Fe content range of this application is between 0.01-0.5%.

[0041] The Ti element content is 0.001-0.2%. A certain amount of Ti is added to the composite aluminum foil. The Al (Ti) with high Ti content and the adjacent Al-based solid solution with low Ti content have different corrosion potentials due to the difference in microscopic composition. Adding an appropriate amount of Ti element can form a cross-distributed aluminum-based solid solution with high Ti content and low Ti content after rolling. This cross-distributed microstructure with different corrosion potentials improves the intergranular corrosion resistance of the composite aluminum foil.

[0042] The Al-Cu binary phase diagram shows that the maximum solid solubility of Cu in Al is 5.65% at 548°C. The equilibrium solid solubility decreases as the temperature decreases, reaching approximately 0.45% at 300°C and 0.1% at room temperature. Due to factors such as the limited high-temperature dwell time and solidification rate during alloy solidification and subsequent processing and welding, Cu typically does not reach a complete equilibrium state in Al. Even under slightly supersaturated conditions, it is difficult to form a second phase. Cu in the alloy increases strength and improves the corrosion potential of the composite aluminum foil. The amount of Cu added to the material of this application does not exceed 0.8%.

[0043] The Zn content ranges from 1.0% to 3.0%. The maximum solid solubility of Zn in aluminum reaches 83.1% at 381°C. The solid solubility decreases continuously with decreasing temperature, reaching approximately 32% at 277°C and 5.6% at 125°C. Because Zn has a certain solid solution strengthening effect on aluminum, higher Zn contents can reduce the alloy's extrusion performance. Furthermore, considering that Zn's effect on reducing the corrosion potential of aluminum is greatest when the Zn content is below approximately 3.00%, the Zn content in this application material does not exceed 3.00%. Since the fins used in composite aluminum foil must have a lower potential than the heat exchange tubes, at least 1% Zn is added to maintain a potential difference of at least 50 mV between the fins and the heat exchange tubes. The Zn content in this application material is not less than 1.00%.

[0044] Si is the main impurity element in the raw materials of electrolytic aluminum. Si exists in the form of solid solution in Al and has a certain solid solution strengthening effect on Al. However, Si is an element that raises the potential of the Al alloy. Excessive Si will reduce the corrosion resistance of the aluminum alloy. Therefore, the content of Si in the core layer 11 is lower than 1.2%.

[0045] Thus, through the setting of the material of the core layer 11, the overall material properties of the composite aluminum foil are improved. And through the setting of the composite layer 12, the Si content in the composite layer 12 is reduced. On the premise of enabling welding, the Si content in the material is reduced, the probability of intergranular corrosion is reduced, and the corrosion resistance of the composite aluminum foil is further enhanced.

[0046] In some embodiments, as Figures 4-6 shown, the second composite layer 122 includes a first layer 1221 and a second layer 1222. Along the thickness direction (up and down direction) of the core layer 11, the first layer 1221 and the second layer 1222 are located on the same side of the core layer 11, and the second layer 1222 is farther from the core layer 11 than the first layer 1221. The first layer 1221 includes a soldering flux.

[0047] Specifically, as Figure 4 and Figure 5 shown, the second composite layer 122 includes a first layer 1221 and a second layer 1222. The first layer 1221 and the second layer 1222 are located on the upper side and the lower side of the core layer 11. Or as Figure 6 shown, the first layer 1221 and the second layer 1222 are located on the lower side of the core layer 11. The second layer 1222 is farther from the core layer 11 than the first layer 1221, that is, the second layer 1222 is located at the outermost layer in the thickness direction of the core layer 11.

[0048] In some embodiments, the first layer 1221 includes a soldering flux and an Al-Si alloy, and the second layer 1222 includes an Al-Si alloy. Among them, the Al-Si alloy is consistent with the material of the second composite layer 122, and the soldering flux is added to the material of the first layer 1221. Optionally, the soldering flux can be a NOCOLOK soldering flux. The soldering flux can be soldering flux powder. After the Al-Si alloy and the soldering flux powder are mixed under high pressure, the first layer 1221 is formed, that is, the soldering flux mixed powder layer. The first layer 1221 and the second layer 1222 are roll-bonded to form the second composite layer 122.

[0049] The first layer 1221 of the second composite layer 122 of the composite aluminum foil includes a soldering flux. Mixing the soldering flux into the composite aluminum foil material avoids the process of separately spraying the soldering flux for welding when the composite aluminum foil is applied and needs to be welded to other components in the subsequent process, reducing the processing procedures. Moreover, when the soldering flux is mixed into the composite aluminum foil material, the soldering flux can be more evenly distributed in the material, which can improve the welding quality. On the other hand, only the second composite layer 122 material that needs to be welded includes the soldering flux, reducing the content of the soldering flux in the overall composite aluminum foil material.

[0050] In this embodiment, the second composite layer 122 includes a first layer 1221 and a second layer 1222. The first layer 1221 includes a soldering flux, and the second layer 1222 is located on the outermost layer in the thickness direction of the core layer 11. Since the second layer 1222 located on the outermost layer of the core layer does not contain a soldering flux, problems such as surface peeling and powder scattering of the composite aluminum foil after rolling can be avoided.

[0051] A dense oxide film is easily formed on the surface of aluminum and its alloys. The melting point of the oxide film is high. When the composite aluminum foil is applied to the fin 1, when the fin 1 and the heat exchange tube 2 are welded, when the temperature rises to 565 °C, the first layer 1221 inside the fin composite layer, that is, the soldering flux layer, begins to melt. The melted soldering flux diffuses to the outside of the fin 1. During the diffusion process, the oxide films on the surfaces of the fin and the heat exchange tube 2 are destroyed, and the fluidity of the solder in the second layer 1222, that is, the outermost solder layer without a soldering flux, is also enhanced. As the temperature continues to rise, the solder melts and flows to the weld to form a weld, and the fin 1 and the heat exchange tube 2 form a metallurgical bond.

[0052] It should be noted here that the second composite layer 122 includes a first layer 1221 and a second layer 1222. The first layer 1221 of the second composite layer 122 includes a soldering flux, while the first composite layer 121 does not include a soldering flux layer. In this way, when the composite aluminum foil is applied to the fin 1, there is no soldering flux residue on the surface of the fin 1. When the heat exchanger is applied, a large amount of soldering flux residue may cause problems such as soldering flux fragmentation, white powder blowing, and odor generation during use. With such a setting, the soldering flux residue can be significantly reduced, improving the appearance and reliability of the heat exchanger.

[0053] In some embodiments, along the thickness direction of the core layer 11, the first layer 1221 is at least one layer, the second layer 1222 is at least one layer, and the first layer 1221 and the second layer 1222 are arranged adjacent to each other.

[0054] Specifically, as Figure 4 and Figure 5 shown, there is 1 layer of the first layer 1221 and 1 layer of the second layer 1222 in the thickness direction of the core layer 11, as Figure 6As shown, there is 1 layer of the first layer 1221 and 2 layers of the second layer 1222 in the thickness direction of the core layer 11. The first layer 1221 and the second layer 1222 are arranged adjacent to and intersecting with each other in the thickness direction of the core layer 11. Of course, it can be understood that 2 or more first layers 1221 and 2 or more second layers 1222 can also be provided, which is not limited herein.

[0055] When a single layer of the first layer 1221 and a single layer of the second layer 1222 are provided, if the flux content in the single-layer first layer 1221 is too high, it may cause breakage during rolling and is not easy to process. On the other hand, if the single-layer first layer 1221 is on the inner side and the outermost side of the fin is the second layer 1222 without flux, the flux is not easy to precipitate to the outside of the composite aluminum foil, which is not conducive to welding. Setting multiple layers of the first layer 1221 and multiple layers of the second layer 1222 to be cross-laminated in the thickness direction of the core layer 11 can increase the fluidity of the solder, which is beneficial to improving the welding performance and making the flux mixed powder layer evenly distributed on the fin 1, enabling more uniform welding, effectively solving the problem of uneven flux flow, and improving the welding quality.

[0056] In some embodiments, the thickness of the first layer 1221 accounts for 5%-90% of the thickness of the second composite layer 122. The first layer 1221 includes an Al-Si alloy and a flux. When the content of the first layer 1221 is less than 5%, the amount of flux cannot meet the requirements and cannot achieve the welding requirements; when the content of the first layer 1221 accounts for more than 90% of the thickness of the composite layer 12, there is too much flux, and defects such as surface peeling and powder scattering may occur after rolling. Therefore, setting the thickness of the first layer 1221 to account for 5%-90% of the thickness of the second composite layer 122 can improve the welding effect between the fin and other components, and improve the welding quality and reliability when the composite aluminum foil is applied to the fin.

[0057] In some embodiments, the composite layer 12 includes a third composite layer 123. In the width direction of the core layer, the third composite layer 123 is located between the first composite layer 121 and the second composite layer 122, and the Si content in the material of the third composite layer 123 is 0.3-9%.

[0058] Specifically, when processing the composite aluminum foil, the first composite layer 121 and the second composite layer 122 are arranged adjacent to each other in the width direction of the core layer 11. During the rolling process of processing the composite aluminum foil, the adjacent first composite layer 121 and second composite layer 122 may cross and penetrate each other. Thus, a third composite layer 123 is formed in the transition zone between the first composite layer 121 and the second composite layer 122. The third composite layer 123 is in the Figure 3 structure as shown. The third composite layer 123 can be in an irregular shape, and a third composite layer 123 may also be formed in other embodiments (not shown in the figure).

[0059] The third composite layer 123 is a transition zone formed between the first composite layer 121 and the second composite layer 122. The Si content is between the Si contents of the first composite layer 121 and the second composite layer 122. The Si content in the material of the third composite layer 123 is 0.3 - 9%, and the Si content does not exceed the maximum Si content of the second composite layer 122. The overall Si content in the composite layer 12 of this composite aluminum foil decreases, and it has good corrosion resistance.

[0060] The embodiment of this application also discloses a processing method for the composite aluminum foil used for fins, including the following steps: providing an aluminum foil, and the aluminum foil forms the core layer 11 by at least melting, casting, and surface cutting; forming the raw material for the first composite layer 121 by at least melting, casting, hot rolling, and cutting, and the Si content in the first composite layer 121 is less than or equal to 1.2%; forming the raw material for the second composite layer 122 by at least melting, casting, hot rolling, and cutting, and the Si content in the second composite layer 122 is greater than or equal to 5% and less than or equal to 12%. First, prepare the raw materials for the core layer 11, the first composite layer 121, and the second composite layer 122.

[0061] Optionally, the core layer 11 is composed of alloy elements with the following mass percentage (wt.%) content ranges: Mn: 0.20 - 2.5%, Fe: 0.01 - 0.5%, Si: 0.3 - 1.2%, Zn: 1.0 - 3.0%, Cu: 0.01 - 0.8%, Ti: 0.001 - 0.2%, the content of each of the remaining alloy elements does not exceed 0.05%, the total content of the remaining alloy elements does not exceed 0.3%, and the balance is Al and unavoidable impurities. Optionally, the first composite layer 121 is composed of alloy elements with the following mass percentage (wt.%) content ranges: Si: 0.3 - 1.2%, Mn: 0.01 - 2.5%, Fe: 0.01 - 0.5%, Zn: 0.02 - 3.0%, Cu: 0.01 - 0.8%, the content of each of the remaining alloy elements does not exceed 0.15%, the total content of the remaining alloy elements does not exceed 0.5%, and the balance is Al and unavoidable impurity elements. Optionally, the second composite layer 122 is composed of alloy elements with the following mass percentage (wt.%) content ranges: Si: 5.0 - 12.0%, Mn: 0.01 - 2.5%, Fe: 0.01 - 0.5%, Zn: 0.02 - 3.0%, Cu: 0.01 - 0.8%, the content of each of the remaining alloy elements does not exceed 0.15%, the total content of the remaining alloy elements does not exceed 0.5%, and the balance is Al and unavoidable impurity elements.

[0062] Place the raw material of the first composite layer 121 on the core layer 11, place the raw material of the second composite layer 122 on the core layer 11, and use hot clad rolling to integrate the laminated core layer 11 and the composite layer 12, thereby forming a rolled material.

[0063] In this embodiment, the raw materials of the first composite layer 121 and the raw materials of the second composite layer 122 are alternately placed on the core layer 11. At this time, the first composite layer 121 and the second composite layer 122 are on the same layer above the core layer 11. The first composite layer 121 and the second composite layer 122 are arranged adjacent to each other along the width direction of the core layer. The thickness of the first composite layer 121 is the same as that of the second composite layer 122. The first composite layer 121 and the second composite layer 122 are alternately placed to form the composite layer 12.

[0064] In some embodiments, the first composite layer 121 can be one, two or more, and the second composite layer 122 can be one, two or more. During processing, the first composite layer 121 and the second composite layer 122 are alternately placed on the same layer of the core layer 11. For example, it can be: the first composite layer 121 and the second composite layer 122 are alternately placed, or the first composite layer 121, the second composite layer 122 and the first composite layer 121 are alternately placed, or the first composite layer 121, the second composite layer 122, the first composite layer 121, the second composite layer 122 and the first composite layer 121 are alternately placed, and it can be processed according to actual needs, which is not limited here.

[0065] Then, the laminated core layer 11 and the composite layer 12 are integrated by hot clad rolling to form a rolled material. It can be understood here that the composite layer 12 can be provided on both sides in the thickness direction of the core layer 11, or the composite layer 12 can be provided only on one side in the thickness direction of the core layer 11. When the composite layer 12 is provided on both sides in the thickness direction of the core layer 11, the composite layer 12, the core layer 11, and the composite layer 12 are arranged in sequence, and the laminated core layer 11 and the composite layer 12 are integrated by hot clad rolling to form a rolled material.

[0066] The rolled material is cold rolled, annealed, and cut, and processed as needed to form a composite aluminum foil. The rolled material is cold rolled, annealed, and cut, and then processed according to different product size requirements to form a two-layer or multi-layer composite aluminum foil.

[0067] According to the method for processing the composite aluminum foil for fins of this embodiment, a composite aluminum foil with good corrosion resistance can be obtained, and the processing is simple; this composite aluminum foil is used to process fins. When this fin is applied to a heat exchanger, while realizing the welding of the fin to other components, the Si content in the fin is reduced, the corrosion resistance of the fin is improved, which is beneficial to improving the corrosion resistance of the heat exchanger.

[0068] In some embodiments, the composite aluminum foil is processed according to the structural requirements of the fins, such as cutting, punching, or grooving according to the dimensions, so that it is processed into the required fins, which can meet the requirements of the heat exchanger and can be better connected to the heat exchange tube 2. Optionally, according to the structural needs of the fins, designs such as adding openings can also be added to improve the heat exchange capacity of the fins, or a reinforcing rib structure can be added to improve the pressure resistance of the fins, which is not limited herein.

[0069] In some specific embodiments, when forming the material of the second composite layer 122, the first layer 1221 containing a brazing agent is formed by at least melting, casting, hot rolling, and cutting. The first layer 1221 includes a brazing agent. The second layer 1222 is formed by at least melting, casting, hot rolling, and cutting. The second layer 1222 does not contain a brazing agent. The second layer 1222 is stacked on the first layer 1221, and / or the first layer 1221 is stacked on the second layer 1222 to form the second composite layer 122.

[0070] The first layer 1221 of the second composite layer 122 of the composite aluminum foil includes a brazing agent. Mixing the brazing agent in the composite aluminum foil material avoids the process of separately spraying the brazing agent for welding when the composite aluminum foil needs to be welded to other components in subsequent applications, reducing the processing steps; and mixing the brazing agent in the composite aluminum foil material, the brazing agent can be more evenly distributed in the material, which can improve the welding quality; on the other hand, only the second composite layer 122 material that needs to be welded includes a brazing agent, reducing the brazing agent content in the overall composite aluminum foil material.

[0071] It can be understood that, in order to meet the requirements of the fin material, multiple first layers 1221 and multiple second layers 1222 can be processed. The first layer 1221 and the second layer 1222 are arranged along the thickness direction of the core layer 11. In some embodiments, the first layer 1221 and the second layer 1222 are stacked and rolled to form the second composite layer 122; or, in some other embodiments, the first layer 1221, the second layer 1222, then the first layer 1221, and the second layer 1222 are stacked and rolled to form the second composite layer 122; or, in some other embodiments, the second layer 1222, the first layer 1221, and the second layer 1222 are stacked and rolled to form the second composite layer 122. Of course, the material of the second composite layer 122 can also adopt other multi-layer structures, which are not limited in this application. Arranging multiple first layers 1221 and multiple second layers 1222 in a stacked design in the thickness direction of the core layer 11 can increase the fluidity of the solder, which is beneficial to improving the welding performance, and make the brazing agent mixed powder layer evenly distributed on the composite aluminum foil, so that the fins using this composite aluminum foil can be more uniform when welded to other components, effectively solving the problem of uneven brazing agent flow and improving the welding quality.

[0072] It should be noted here that during the processing, when the first layer 1221 and the second layer 1222 are multi-layers, the second layer 1222 is located on the outermost side of the core layer 11 in the thickness direction of the core layer. Since the second layer 1222 does not contain a brazing agent, problems such as surface peeling and powder scattering after rolling of the composite aluminum foil can be avoided, which may affect the appearance and welding quality.

[0073] The present application also provides a fin. The fin material includes the above-mentioned composite aluminum foil. The fin includes a plurality of through holes or through grooves, and the plurality of through holes or through grooves are arranged at intervals along the length direction of the fin. In the width direction of the fin, near the through hole or through groove, the fin material includes a second composite layer, and away from the through hole or through groove, the fin material includes a first composite layer.

[0074] Specifically, the material of the fin 1 includes the above-mentioned composite aluminum foil. The fin 1 uses the above-mentioned composite aluminum foil as the raw material and is formed by processing the above-mentioned composite aluminum foil according to the structure requirements of the fin 1. The composite aluminum foil is formed by using the above-mentioned processing method of the composite aluminum foil. As Figures 7a-12b shown, the fin 1 includes a plurality of through holes 13 or through grooves 14. The through holes 13 or through grooves 14 of the fin are used to fit and install the heat exchange tube 2. The plurality of through holes 13 or through grooves 14 are arranged at intervals along the length direction of the fin 1. The length direction of the fin 1 is the y direction in the figure, that is, the up and down direction. The width direction of the fin 1 is the x direction in the figure, that is, the left and right direction. The thickness direction of the fin 1 is the z direction in the figure, and the thickness direction of the fin 1 is the same as the thickness direction of the core layer.

[0075] In the width direction x of the fin 1, near the through hole 13 or through groove 14 of the fin 1, the composite layer material of the fin 1 includes a second composite layer 122, and away from the through hole 13 or through groove 14, the composite layer material of the fin 1 includes a first composite layer 121. It can be understood that in the thickness direction z of the fin 1, the core layer material of the fin 1 is the same, and the material of the composite layer 12 is different near or away from the through hole 13 or through groove 14.

[0076] In this embodiment, at the through holes 13 or through grooves 14 of the fin 1, it is necessary to adapt and connect the heat exchange tube 2. The fin 1 needs to be connected to the heat exchange tube 2 by welding or other means. In order to realize the welding of the fin 1 and the heat exchange tube 2, the material of the fin 1 at the through holes 13 or through grooves 14 includes a second composite layer 122, and the Si content of the second composite layer 122 is greater than or equal to 5% and less than or equal to 12%, which is convenient for welding with the heat exchange tube 2. At the position of the fin far from the through holes 13 or through grooves 14, the fin 1 does not need to be welded to other components, and the fin material includes a first composite layer 121, and the Si content of the first composite layer 121 is less than or equal to 1.2%. Thereby, the Si content of the composite layer in the fin is reduced, and the intergranular corrosion caused by Si diffusion is reduced, improving the corrosion resistance of the fin. Thus, the design of the fin in this application can reduce the intergranular corrosion while realizing welding, improve the corrosion resistance of the fin. Further, after the corrosion resistance of the fin is improved, the fin is not easily damaged, avoiding the influence of the damage of the fin on the heat exchange on the air side of the heat exchanger. At the same time, after the corrosion resistance of the fin is improved, the protection of the heat exchange tube 2 connected to the fin is also enhanced, improving the heat exchange performance of the heat exchanger.

[0077] In some embodiments, such as Figure 7a , Figure 7b , Figure 10a , Figure 10b shown, along the width direction x of the fin 1, near the through hole 13, the composite layer 12 material in the thickness direction of the fin is the second composite layer 122. A plurality of through holes 13 are arranged at intervals along the length direction y of the fin. Along the length direction y of the fin, the composite layer material of the fin near the through hole 13 includes the second composite layer 122. At the position far from the through hole 13, the composite layer material of the fin includes the first composite layer 121, and the first composite layer 121 and the second composite layer 122 are arranged adjacent to each other in the width direction x of the fin 1.

[0078] In this embodiment, the fin material includes the composite layer 12 on both sides in the thickness direction of the fin 1. It can be understood that the composite layer 12 can also be included only on one side in the thickness direction of the fin. When there is a composite layer 12 only on one side in the thickness direction of the fin, the fin can be welded to the heat exchange tube connected thereto through the side with the composite layer 12, and the overall Si content of the composite layer is reduced, which can further improve the corrosion resistance of the fin. A plurality of through holes 13 of the fin 1 are arranged at intervals along the length direction y of the fin. Correspondingly, the first composite layer 121 and the second composite layer 122 arranged adjacent to each other in the width direction of the fin 1 also extend along the length direction y of the fin 1.

[0079] In some embodiments, such as Figure 12a and 12bAs shown, the fin 1 includes a plurality of through grooves 14. Near the through grooves 14, the fin 2 material includes a second composite layer 122. The plurality of through grooves 14 are arranged at intervals along the length direction y of the fin. In the length direction x of the fin, the fin material near the through grooves 14 includes the second composite layer 122. Away from the through grooves 14, the fin material includes a first composite layer 121. The first composite layer 121 and the second composite layer 122 are arranged adjacent to each other along the width direction x of the fin 1.

[0080] In this embodiment, the fin material on one side in the thickness direction of the fin 1 includes a composite layer 12. The fin can be welded to the heat exchange tube 2 connected thereto through the side with the composite layer 12, further reducing the overall Si content of the composite layer and further improving the corrosion resistance of the fin. It can be understood that the fin material on both sides in the thickness direction of the fin 1 can also include the composite layer 12. The plurality of through grooves 14 of the fin 1 are arranged at intervals along the length direction y of the fin. Correspondingly, the first composite layer 121 and the second composite layer 122 arranged adjacent to each other in the width direction of the fin 1 also extend along the length direction y of the fin 1.

[0081] In some embodiments, the fin 1 includes a first side edge 1a and a second side edge 1b arranged opposite to each other along the width direction of the fin. The material of the fin 1 at the first side edge 1a and / or the second side edge 1b includes the first composite layer 121.

[0082] Specifically, as Figure 7a 、 10a and Figure 12a shown, in the width direction x of the fin 1, that is, the left - right direction in the figure, the fin 1 includes a first side edge 1a and a second side edge 1b. The material of the fin 1 near the first side edge 1a and / or the second side edge 1b includes the first composite layer 121. It can be understood that the first composite layer 121 material can be included only near the first side edge 1a of the fin 1, or only near the second side edge 1b of the fin 1, or the first composite layer 121 material can be included near both the first side edge 1a and the second side edge 1b of the fin 1.

[0083] When the fin is applied to a heat exchanger, during the operation of the heat exchanger 100, air will flow through the heat exchanger along the width direction of the fin. On both sides of the width direction of the fin, especially on the windward side, the air volume is large and the heat transfer performance is better. Therefore, the corrosion resistance of the fin 1 on the windward side needs to be better. The fin 1 is arranged at a position close to the first side 1a or the second side 1b. The fin material includes the first composite layer 121. Alternatively, the fin includes the first composite layer 121 material at both the position close to the first side 1a and the second side 1b of the fin 1. The Si content in the first composite layer 121 is less than or equal to 1.2%. Thus, the intergranular corrosion of the fin 1 caused by the diffusion of Si elements at the first side 1a and / or the second side 1b can be reduced, and the corrosion or pulverization of the edge fins can be avoided, which affects the heat transfer performance of the heat exchanger, thereby improving the heat transfer performance and reliability of the heat exchanger.

[0084] In some embodiments, along the width direction of the fin, the distance between the edge of the through hole 13 or the through groove 14 on the fin and the edge of the adjacent first composite layer 121 is t, and the range of t is 0 - 10 mm.

[0085] Specifically, as Figure 7a , Figure 10a and Figure 12a shown, along the width direction x of the fin, that is, the left - right direction, the distance between the edge of the through hole 13 or the through groove 14 on the fin and the edge of the adjacent first composite layer is t, and the range of t is 0 - 10 mm. The through hole 13 or the through groove 14 on the fin is used to insert the heat exchange tube 2 and is welded to the fin 1. The fin material near the through hole 13 or the through groove 14 includes the second composite layer 122. Setting t > 0 enables the fin 1 to include a certain distance of the second composite layer 122 material in the width direction of the fin. The Si content of the second composite layer 122 material is greater than or equal to 5% and less than or equal to 12%, so as to realize the welding of the fin 1 and the heat exchange tube 2. When t > 10 mm, the width of the second composite layer 122 material in the width direction x of the fin is too large, which will cause the width of the first composite layer 121 material in the width direction x of the fin to be too small. And the Si content in the first composite layer 122 material is less than or equal to 1.2%, which will increase the Si content in the overall fin and is not conducive to improving the corrosion resistance of the fin. Therefore, setting 0 < t ≤ 10 mm is beneficial to further improve the corrosion resistance of the fin and the corrosion resistance of the heat exchanger while ensuring the welding quality.

[0086] Furthermore, at the through holes 13 or through grooves 14 near both sides of the fin 1 in the width direction, the materials of the adjacent first composite layers 121 are close to the first side 1a or the second side 1b. When t is greater than 10 mm, the width of the second composite layer 122 material in the width direction x of the fin is too large, and the dimensions of the fin 1 near the first side 1a or the second side 1b in its width are too small. In this way, the fin is prone to damage or fragmentation near the first side 1a or the second side 1b. The damage or fragmentation of the fin edge will affect the overall heat exchange performance of the heat exchanger. Therefore, setting t greater than 0 and less than or equal to 10 mm is beneficial to improving the welding quality, enhancing the corrosion resistance of the heat exchanger, and improving the heat exchange performance of the heat exchanger.

[0087] The following describes the fin for a heat exchanger according to a specific embodiment of the present invention.

[0088] As Figure 7a shown, the fin 1 includes a plurality of through holes 13. Three columns of through holes 13 are arranged along the width direction of the fin. The three columns of through holes 13 are spaced apart along the width direction of the fin 1, and the plurality of through holes 13 in each column are spaced apart along the length direction of the fin. In Figure 7a , the width direction of the fin 1 is the x direction, that is, Figure 7a the left - right direction in Figure 7a , and the length direction of the fin is the y direction, that is,

[0089] As Figure 7b shown, the material of the fin 1 includes a core layer 11 and a composite layer 12. The core layer 11 and the composite layer 12 are arranged along the thickness direction of the fin. Figure 7b The z direction in

[0090] is the thickness direction of the fin. Composite layers 12 are provided on both sides of the core layer 11 in the thickness direction. It can be understood that there may also be only a composite layer 12 on one side of the fin in the thickness direction. Figure 7b The left - right direction in

[0091] In the width direction of the fin, the fin material near the through hole 13 includes the second composite layer 122. The through hole 13 on the fin 1 facilitates the insertion of the heat exchange tube and is welded to the heat exchange tube. The fin material far from the through hole 13 includes the first composite layer 121. Thus, in the width direction of the fin, the first composite layer 121 and the second composite layer 122 of the composite layer 12 of the fin 1 are arranged adjacent to each other. And on both sides in the width direction of the fin 1, the fin material includes the first composite layer 121.

[0092] For ease of understanding, Figure 7b the different composite layer materials at different positions in the thickness direction z of the fin material in Figure 7a are marked. In this embodiment, the first composite layer 121, the second composite layer 122, the first composite layer 121, the second composite layer 122, the first composite layer 121, the second composite layer 122, and the first composite layer 121 of the fin composite layer 12 are arranged in sequence along the width direction of the fin. The multiple through holes 13 of the fin are arranged at intervals along the length direction of the fin. For ease of welding, the first composite layer 121 and the second composite layer 122 also extend along the length direction of the fin.

[0093] In the second composite layer material of the fin 1 at the through hole 13, the Si element is greater than or equal to 5% and less than or equal to 12%, which is convenient for welding with the heat exchange tube. In the first composite layer material far from the through hole 13, the Si element is less than or equal to 1.2%, reducing the overall Si content of the fin, which is beneficial to reducing intergranular corrosion and improving the corrosion resistance of the fin. At the same time, on both sides in the width direction (left and right direction) of the fin 1, the composite layer material of the fin 1 includes the first composite layer 121, and the Si element in the first composite layer 121 material is less than or equal to 1.2%, which is more beneficial to improving the corrosion resistance of the fin 1.

[0094] The following describes the fin for a heat exchanger according to another specific embodiment of the present invention.

[0095] As Figure 10a shown, the fin 1 includes multiple through holes 13. The multiple through holes 13 are arranged at intervals along the length direction y of the fin, and there is 1 row of through holes arranged in the width direction x of the fin.

[0096] As Figure 10b shown, the material of the fin 1 includes a core layer 11 and a composite layer 12. The core layer 11 and the composite layer 12 are arranged along the thickness direction z of the fin, Figure 10b where the thickness direction of the fin in

[0097] is the up and down direction. There are composite layers 12 on both sides in the thickness direction of the core layer 11. Of course, the composite layer 12 can also be located on one side in the thickness direction of the core layer 11. The composite layer 12 includes the first composite layer 121 and the second composite layer 122 arranged at intervals in the width direction of the fin.Figure 10b The width direction of the middle fin is the left - right direction. Along the width direction of the fin, the material of the fin near the through - hole 13 includes the second composite layer 122. The through - hole 13 on the fin 1 facilitates the insertion of the heat - exchange tube and is welded to the heat - exchange tube. The fin material far from the through - hole 13 of the fin 1 includes the first composite layer 121. Thus, in the width direction of the fin, the first composite layer 121, the second composite layer 122, and the first composite layer 121 of the fin 1 are arranged at intervals. On both sides in the width direction of the fin 1, the fin material includes the first composite layer 121.

[0098] For the sake of easy understanding, Figure 10b the different composite layer 12 materials at different positions in the thickness direction of the fin material in Figure 10a are marked. In this embodiment, the first composite layer 121, the second composite layer 122, and the first composite layer 121 of the fin composite layer 12 are arranged in sequence along the width direction of the fin. In the second composite layer material near the through - hole 13 of the fin 1, the Si element is greater than or equal to 5% and less than or equal to 12%, which is convenient for welding with the heat - exchange tube. In the first composite layer material far from the through - hole 13, the Si element is less than or equal to 1.2%. While achieving welding, the Si content is reduced, which is beneficial to reducing intergranular corrosion and improving the corrosion resistance of the fin.

[0099] The fin for a heat exchanger according to another specific embodiment of the present invention will be described below.

[0100] As Figure 12a shown, the fin 1 includes a plurality of through - slots 14. The plurality of through - slots 14 are arranged at intervals along the length direction of the fin. The length direction of the fin is the Figure 12a y - direction in

[0101] As Figure 12b shown, the material of the fin 1 includes a core layer 11 and a composite layer 12. The core layer 11 and the composite layer 12 are arranged along the thickness direction z of the fin. Figure 12b The thickness direction of the middle fin is the up - down direction. There is a composite layer 12 on one side in the thickness direction of the fin. When there is only a composite layer 12 on one side in the thickness direction of the fin, the fin can be welded to the heat - exchange tube connected to it through the side with the composite layer 12, and the overall Si content of the composite layer is reduced, which can further improve the corrosion resistance of the fin.

[0102] The composite layer 12 includes a first composite layer 121 and a second composite layer 122 arranged at intervals in the width direction of the fin. Figure 12bThe width direction of the middle fin is the left - right direction. Along the width direction of the fin, the material of the fin near the through - slot 14 includes the second composite layer 122. The through - slot 14 on the fin 1 facilitates the installation of the heat - exchange tube. The heat - exchange tube 2 is adaptively installed in the through - slot 14 and is welded to the fin 1. The fin material far from the through - slot 14 of the fin 1 includes the first composite layer 121. Thus, in the width direction x of the fin, the first composite layer 121, the second composite layer 122, and the first composite layer 121 of the fin 1 are arranged at intervals. On both sides of the fin 1 in the width direction (left - right direction), the fin material includes the first composite layer 121.

[0103] For ease of understanding, Figure 12b the different composite layer 12 materials at different positions in the thickness direction z of the fin material in Figure 12a are marked. In this embodiment, the first composite layer 121, the second composite layer 122, and the first composite layer 121 of the fin composite layer 12 are arranged in sequence. In the second composite layer material of the fin 1 near the through - slot 14, the Si element is greater than or equal to 5% and less than or equal to 12%, which is convenient for welding connection with the heat - exchange tube 2. In the first composite layer material far from the through - slot 14, the Si element is less than or equal to 1.2%. While achieving welding, the Si content is reduced, which is beneficial to reducing intergranular corrosion and improving the corrosion resistance of the fin.

[0104] In the related art, the heat - exchange tube and the fin are connected by the tube - expanding method. When tube - expanding, there is a gap between the heat - exchange tube and the fin, resulting in too large a thermal resistance between the heat - exchange tube and the fin, reducing the heat - exchange performance of the heat exchanger. In order to reduce the thermal resistance between the heat - exchange tube and the fin and improve the heat - exchange performance, the heat - exchange tube and the fin are connected by welding. When the heat - exchange tube and the fin are welded, generally, brazing is carried out with an Al - Si - based alloy solder. The Si enriched at the grain boundaries during welding will cause corrosion to proceed along the grain boundaries, resulting in intergranular corrosion, affecting the reliability of the material and the reliability and heat - exchange performance of the heat exchanger.

[0105] The embodiment of the present application discloses a heat exchanger, as Figure 8 shown, the heat exchanger 100 includes: a first tube 3, a second tube 4, and a plurality of heat - exchange tubes 2. The first tube 3 and the second tube 4 are arranged at intervals. One end of the heat - exchange tube 2 is connected to the first tube 3, and the other end of the heat - exchange tube 2 is connected to the second tube 4 to connect the first tube 3 and the second tube 4. Specifically, the first tube 3 and the second tube 4 are arranged at intervals, and the heat - exchange tubes 2 are connected between the first tube 3 and the second tube 4 to connect the first tube 3 and the second tube 4. The plurality of heat - exchange tubes 2 are arranged at intervals along the length direction of the fin.

[0106] The heat exchanger 100 further includes fins, and the fins adopt the above - mentioned fins, as Figures 7a-12bAs shown, the fin 1 includes a plurality of through holes 13 or through slots 14, and the plurality of through holes 13 or through slots 14 are arranged at intervals along the length direction of the fin 1. In the width direction of the fin 1, near the through holes 13 or through slots 14 of the fin 1, the composite layer material of the fin 1 includes a second composite layer 122, and away from the through holes 13 or through slots 14, the composite layer material of the fin 1 includes a first composite layer 121. The length direction of the fin 1 is the y direction in the figure, that is, the up and down direction, and the width direction of the fin 1 is the x direction in the figure, that is, the left and right direction.

[0107] The heat exchange tube 2 is adaptively installed in the through hole 13 or through slot 14, and the fin 1 and the heat exchange tube 2 are welded and connected through the second composite layer of the fin. Specifically, as Figure 7a and Figure 10a shown, the fin 1 includes a plurality of through holes 13, the heat exchange tube 2 is inserted into the through holes 13 of the fin 1 and is welded and connected to the fin 1; as Figure 11 and Figure 12a shown, the fin 1 includes a plurality of through slots 14, the heat exchange tube 2 is adaptively installed in the through slots 14, and the fin 1 and the heat exchange tube 2 are welded and connected. The fin 1 and the heat exchange tube 2 are welded and connected through the second composite layer 122 of the fin. Optionally, the welding method is brazing.

[0108] In this embodiment, near the through holes 13 or through slots 14 of the fin 1, it is necessary to adaptively connect the heat exchange tube 2, and the fin 1 needs to be connected to the heat exchange tube 2 by welding or other means. In order to realize the welding of the fin 1 and the heat exchange tube 2, the material of the fin 1 at the through holes 13 or through slots 14 includes a second composite layer 122, and the Si content of the second composite layer 122 is greater than or equal to 5% and less than or equal to 12%, which is convenient for welding with the heat exchange tube 2. Away from the through holes 13 or through slots 14 of the fin, the fin 1 does not need to be welded to other components, and the fin material includes a first composite layer 121, and the Si content of the first composite layer 121 is less than or equal to 1.2%, thereby reducing the Si content in the fin and avoiding intergranular corrosion caused by Si diffusion.

[0109] The heat exchanger of the present application uses the above-mentioned fins, which can reduce the Si content in the fins while realizing welding with the heat exchange tube, reduce the probability of intergranular corrosion, improve the corrosion resistance of the fins, further improve the corrosion resistance and reliability of the heat exchanger, and is beneficial to improving the service life of the heat exchanger. Further, after the corrosion resistance of the fins is improved, the fins are not easily damaged, avoiding the influence of the damage of the fins on the heat exchange on the air side of the heat exchanger and improving the heat exchange performance of the heat exchanger.

[0110] It can be understood that the heat exchanger can be provided with two rows or more rows of heat exchange tubes 2 in the width direction x of the fin, such as Figure 7aIn the illustrated embodiment, when multiple rows of heat exchange tubes 2 are provided, the fin 1 is provided with multiple rows of through holes 13 in the width direction x thereof. The composite layer material of the fin 1 in its width direction may include a first composite layer 121, a second composite layer 122, a first composite layer 121, a second composite layer 122, and a first composite layer 121 arranged alternately to adapt to different heat exchanger structures, which is not limited herein.

[0111] It should be noted that in the present invention, relative terms such as "first" and "second" are only used to distinguish one entity or unit from another entity or unit, and do not necessarily require or imply any actual relationship or order between these entities or units. And herein, the meaning of "a plurality" is at least two, unless otherwise specifically defined.

[0112] In the description of this specification, the description referring to terms such as "an embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0113] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A composite aluminum foil for fins, characterized in that, The composite aluminum foil material includes: a core layer, the material of the core layer being aluminum or aluminum alloy, the core layer including a first side and a second side oppositely arranged in the thickness direction of the core layer; a composite layer, the composite layer being provided on at least one of the first side and the second side, the composite layer including at least one first composite layer and at least one second composite layer, the first composite layer and the second composite layer being adjacently arranged along the width direction of the core layer, by mass percentage, the Si content in the material of the first composite layer being less than or equal to 1.2%, and the Si content in the material of the second composite layer being greater than or equal to 5% and less than or equal to 12%.

2. The composite aluminum foil for fins according to claim 1, characterized in that, By mass percentage, the Si content in the material of the first composite layer is 0.3 - 1.2%, and it further includes: Mn: 0.01 - 2.5%, Fe: 0.01 - 0.5%, Zn: 0.02 - 3.0%, Cu: 0.01 - 0.8%, Al and inevitable impurity elements.

3. The composite aluminum foil for fins according to claim 1, characterized in that, By mass percentage, the material of the second composite layer further includes: Mn: 0.01 - 2.5%, Fe: 0.01 - 0.5%, Zn: 0.02 - 3.0%, Cu: 0.01 - 0.8%, Al and inevitable impurity elements.

4. The composite aluminum foil for fins according to any one of claims 1-3, characterized in that, The thickness of the composite layer accounts for 6% - 15% of the thickness of the composite aluminum foil.

5. The composite aluminum foil for fins according to any one of claims 1-3, characterized in that, The second composite layer includes a first layer and a second layer. Along the thickness direction of the core layer, the first layer and the second layer are located on the same side of the core layer, the second layer is farther from the core layer than the first layer, and the first layer includes a soldering agent.

6. The composite aluminum foil for fins according to claim 5, characterized in that, Along the thickness direction of the core layer, the first layer is at least one layer, the second layer is at least one layer, and the first layer and the second layer are adjacently arranged.

7. The composite aluminum foil for fins according to any one of claims 1-3, characterized in that The composite layer further includes a third composite layer. In the width direction of the core layer, the third composite layer is located between the first composite layer and the second composite layer, and the Si content in the material of the third composite layer is 0.3 - 9%.

8. A processing method for composite aluminum foil for fins, characterized in that, It includes the following steps: Providing an aluminum foil, the aluminum foil forming the core layer by at least melting, casting, and surface cutting; Forming a raw material for the first composite layer by at least melting, casting, hot rolling, and cutting, with the Si content in the first composite layer being less than or equal to 1.2%; Forming a raw material for the second composite layer by at least melting, casting, hot rolling, and cutting, with the Si content in the second composite layer being greater than or equal to 5% and less than or equal to 12%; Placing the raw material of the first composite layer on the core layer, placing the raw material of the second composite layer on the core layer, the first composite layer and the second composite layer being adjacently arranged along the width direction of the core layer, at least part of the first composite layer and at least part of the second composite layer forming the composite layer, and integrally combining the laminated core layer and the composite layer by hot cladding rolling to form a rolled material; Cold rolling, annealing, and cutting the rolled material, and processing it as required to form a composite aluminum foil.

9. A method for processing a composite aluminum foil for fins according to claim 8, characterized in that, The processing method further includes: when forming the second composite layer, forming a first layer by at least performing melting, casting, hot rolling, and cutting, the first layer including a brazing flux, forming a second layer by at least performing melting, casting, hot rolling, and cutting, stacking the second layer on the first layer, and / or stacking the first layer on the second layer to form the second composite layer.

10. A fin, characterized in that, The fin material includes the composite aluminum foil according to any one of claims 1-7. The fin includes a plurality of through holes or through grooves, and the plurality of through holes or through grooves are arranged at intervals along the length direction of the fin. In the width direction of the fin, near the through holes or through grooves, the material of the fin includes the second composite layer, and away from the through holes or through grooves, the material of the fin includes the first composite layer.

11. The fin according to claim 10, characterized in that, The fin includes a first side edge and a second side edge that are oppositely arranged along the width direction of the fin. The material of the fin near the first side edge and / or the second side edge includes the first composite layer.

12. The fin according to claim 10 or 11, characterized in that, In the width direction of the fin, the distance between the edge of the fin at the through hole or through groove and the edge of the adjacent first composite layer is t, and the range of t is 0-10 mm.

13. A heat exchanger, characterized in that, The heat exchanger includes a first pipe, a second pipe, and a plurality of heat exchange pipes. The first pipe and the second pipe are arranged at intervals. One end of the heat exchange pipe is connected to the first pipe, and the other end of the heat exchange pipe is connected to the second pipe to communicate the first pipe and the second pipe. The heat exchanger further includes fins, the fins being the fins according to any one of claims 10-12. The heat exchange pipes are adaptively installed in the through holes or through grooves, and the heat exchange pipes and the fins are welded through the second composite layer.

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