Composite aluminum foil for fin, fin using same, and heat exchanger

Abstract

Disclosed in the present application are a composite aluminum foil for a fin, a fin using same, and a heat exchanger comprising the fin. The composite aluminum foil material comprises: a core layer (11), the material of the core layer (11) being aluminum or aluminum alloy, and the core layer (11) comprising a first side surface and a second side surface which are arranged opposite to each other in the thickness direction of the core layer (11); and a composition layer (12), the composition layer (12) being provided on at least one of the first side surface and the second side surface, the composition layer (12) comprising at least one first composition layer (121) and at least one second composition layer (122), and the first composition layer (121) and the second composition layer (122) being arranged adjacent to each other in the width direction of the core layer (11), wherein, in percentage by mass, the content of Si in the material of the first composition layer (121) is less than or equal to 1.2%, and the content of Si in the material of the second composition layer (122) is greater than or equal to 5% and less than or equal to 12%.

Description

Composite aluminum foil for fins and fins and heat exchangers using the same

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present disclosure is based on and claims the priority of Chinese patent applications with application number 202410116443.0 and application date on January 26, 2024, and Chinese patent application with application number 202411729528.2 and application date on November 28, 2024. The entire contents of the Chinese patent applications are hereby incorporated into the present disclosure by reference. Technical Field

[0003] The present disclosure relates to the field of heat exchange technology, and in particular to a composite aluminum foil for fins and a fin and a heat exchanger using the same. Background Art

[0004] Aluminum alloy heat exchangers are widely used in related technologies. These heat exchangers consist of heat exchange tubes and fins, which are welded to the tubes to enhance heat exchange with the air. The corrosion resistance of the fins not only affects the heat transfer performance of the heat exchanger but also affects its lifespan, making them a key indicator of fin performance. Summary of the Invention

[0005] On the one hand, the present disclosure proposes a composite aluminum foil for fins and a processing method thereof. The application of the composite aluminum foil in fins is beneficial to reducing intergranular corrosion and improving corrosion resistance.

[0006] On the other hand, the present disclosure also provides a fin, which is beneficial for reducing intergranular corrosion and improving corrosion resistance.

[0007] On the other hand, the present disclosure further proposes a heat exchanger. The fin is applied to the heat exchanger, which improves the corrosion resistance of the heat exchanger and helps to increase the service life of the heat exchanger.

[0008] According to an embodiment of the first aspect of the present disclosure, a composite aluminum foil for a fin is provided. The composite aluminum foil material includes:

[0009] a core layer, wherein the material of the core layer is aluminum or an aluminum alloy, and the core layer includes a first side surface and a second side surface that are oppositely arranged in a thickness direction of the core layer;

[0010] A composite layer, the composite layer being arranged on at least one of the first side surface and the second side surface, 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, and 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%, by mass percentage.

[0011] In this embodiment, the composite aluminum foil material is prepared by arranging a composite layer outside the core layer, 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 are adjacently arranged along the width direction of the core layer, the Si content in the first composite layer is less than or equal to 1.2%, the Si content in the second composite layer is greater than or equal to 5% and less than or equal to 12%, 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 welding connection with other components, and the Si content in the first composite layer is less than or equal to 1.2%. When the composite aluminum foil is applied to the fin, while being able to be welded with other components, the Si content in the composite aluminum foil material is reduced, which is beneficial to reducing intergranular corrosion and improving corrosion resistance.

[0012] According to another embodiment of the present disclosure, a method for processing a composite aluminum foil for a fin is provided, comprising the following steps:

[0013] An aluminum foil is provided, wherein the aluminum foil is formed into a core layer by at least melting, casting, and surface cutting;

[0014] Forming a raw material for a first composite layer by at least melting, casting, hot rolling, and cutting, wherein the Si content in the first composite layer is less than or equal to 1.2%;

[0015] forming a raw material for a second composite layer by at least melting, casting, hot rolling, and cutting, wherein a Si content in the second composite layer is greater than or equal to 5% and less than or equal to 12%;

[0016] 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 forming a composite layer, and integrating the laminated core layer and the composite layer by hot cladding rolling, thereby forming a rolled material;

[0017] The rolled material is cold rolled, annealed, and cut, and processed as needed to form a composite aluminum foil.

[0018] 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 to improving the corrosion resistance and reliability of the fins.

[0019] On the other hand, the present disclosure provides a fin, wherein the fin material includes the above-mentioned composite aluminum foil, and the fin includes a plurality of through holes or through slots, and the plurality of through holes or through slots are spaced apart along the length direction of the fin. In the width direction of the fin, near the through holes or the through slots, the material of the fin includes the second composite layer, and away from the through holes or the through slots, the material of the fin includes the first composite layer.

[0020] In this embodiment, the fin material includes the above-mentioned composite aluminum foil, and the fin is formed by processing the above-mentioned composite aluminum foil as needed. The fin includes a through hole or a through slot, and the fin is connected to other components through the through hole or the through slot. In the width direction of the fin, near the through hole or the through slot, the material of the fin 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 fin with other components. Far away from the through hole or the through slot, the material of the fin includes a first composite layer, and the Si content in the first composite layer is less than or equal to 1.2%, thereby reducing the Si content in the fin while achieving welding of the fin with other components, which is beneficial to reducing intergranular corrosion and improving the corrosion resistance of the fin.

[0021] According to another embodiment of the present disclosure, a heat exchanger is proposed, which includes a first tube, a second tube and a plurality of heat exchange tubes, wherein the first tube and the second tube are arranged at intervals, one end of the heat exchange tube is connected to the first tube, and the other end of the heat exchange tube is connected to the second tube to connect the first tube and the second tube; the heat exchanger also includes fins, which are the above-mentioned fins, and the heat exchange tubes are adapted to be installed in the through holes or the through grooves, and the heat exchange tubes and the fins are welded through the second composite layer.

[0022] According to the heat exchanger of this embodiment, the fins of the embodiment of the present disclosure are adopted, and the heat exchange tubes are adapted to be installed in the through holes or through grooves. At the connection between the fins and the heat exchange tubes near the through holes or through grooves, the material of the fins 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%, so as to realize the welding connection between the fins and the heat exchange tubes. At the connection away from the fins and the heat exchange tubes, the material of the fins includes a first composite layer, and the Si content in the first composite layer is less than or equal to 1.2%. Therefore, while realizing the welding between the fins and the heat exchange tubes, the Si content in the fins is reduced, the probability of intergranular corrosion is reduced, the corrosion resistance of the fins is improved, and the corrosion resistance of the heat exchange tubes connected to the fins is improved, the overall corrosion resistance of the heat exchanger is improved, and it is beneficial to increase the service life of the heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG1 is a schematic structural diagram of a composite aluminum foil according to an embodiment of the present disclosure;

[0024] FIG2 is a schematic structural diagram of another composite aluminum foil according to an embodiment of the present disclosure;

[0025] FIG3 is a schematic structural diagram of another composite aluminum foil according to an embodiment of the present disclosure;

[0026] FIG4 is a schematic structural diagram of another composite aluminum foil according to an embodiment of the present disclosure;

[0027] FIG5 is a schematic structural diagram of another composite aluminum foil according to an embodiment of the present disclosure;

[0028] FIG6 is a schematic structural diagram of another composite aluminum foil according to an embodiment of the present disclosure;

[0029] FIG7 a is a schematic structural diagram of a fin for a heat exchanger according to an embodiment of the present disclosure;

[0030] FIG7b is a schematic structural diagram of the fin material in FIG7a;

[0031] FIG8 is a schematic structural diagram of a heat exchanger according to an embodiment of the present disclosure;

[0032] FIG9 is a schematic diagram of a partial structure of a heat exchanger according to an embodiment of the present disclosure;

[0033] FIG10a is a schematic structural diagram of another heat exchanger fin according to an embodiment of the present disclosure;

[0034] FIG10b is a schematic structural diagram of the fin material in FIG10a;

[0035] FIG11 is a schematic diagram of a partial structure of another heat exchanger according to an embodiment of the present disclosure;

[0036] FIG12a is a schematic structural diagram of another heat exchanger fin according to an embodiment of the present disclosure;

[0037] FIG12 b is a schematic structural diagram of the fin material in FIG12 a .

[0038] 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 DESCRIPTION

[0039] The following describes in detail embodiments of the present disclosure, with examples of the embodiments illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present disclosure, and should not be construed as limiting the present disclosure. All other technical solutions derived by persons of ordinary skill in the art without inventive effort are intended to fall within the scope of protection of the present disclosure.

[0040] The terms used in the embodiments of the present disclosure are for the purpose of describing specific embodiments only and are not intended to limit the present disclosure. The singular forms "a," "an," "the," and "the" used in the embodiments of the present disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0041] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0042] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or meta-fixture referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present disclosure.

[0043] In addition to corrosion resistance, the composite aluminum foil and fins of the disclosed embodiments require design of their elemental composition and content to meet the strength and processing and manufacturing performance requirements required of composite aluminum foil and fin components. The following describes the elemental composition and additive amounts of the aluminum alloy materials included in the composite aluminum foil and fins of the disclosed embodiments. Unless otherwise specified, the alloying element contents of the aluminum alloy materials in the disclosed embodiments refer to mass content.

[0044] A composite aluminum foil according to an embodiment of the present disclosure, as shown in Figures 1-6, includes a core layer 11. The material of core layer 11 is aluminum or an aluminum alloy, wherein the aluminum of core layer 11 is industrial pure aluminum, and the aluminum alloy of core layer 11 can be rust-proof aluminum, aluminum-zinc alloy, or other aluminum alloys. Core layer 11 includes a first side surface and a second side surface disposed opposite each other in the thickness direction of core layer 11; the thickness direction of core layer 11 is the vertical direction in Figures 1-6, and core layer 11 includes an upper side surface and a lower side surface disposed opposite each other in the vertical direction.

[0045] The composite layer 12 is made of aluminum alloy and is provided on at least one of the first side and the second side. That is, as shown in FIG1 , the composite layer 12 may be provided only on the first side of the core layer 11, or only on the second side of the core layer 11. Alternatively, as shown in FIG2 , composite layers 12 may be provided outside the first and second side surfaces of the core layer 11, that is, composite layers 12 may be provided on the upper side surface and outside the upper side surface of the core layer 11.

[0046] As shown in Figures 1-6, 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 adjacently arranged along the width direction of the core layer 11. The width direction of the core layer 11 is the left and right direction in Figures 1-6. The first composite layer 121 and the second composite layer 122 are located in the same layer in the thickness direction of the core layer 11. As shown in Figures 1, 2, 4 and 6, the composite aluminum foil may have a first composite layer 121 and a second composite layer 122 along the width direction of the core layer 11, with the first composite layer 121 and the second composite layer 122 arranged adjacent to each other. Alternatively, as shown in Figure 5, the composite aluminum foil may have a first composite layer 121, a second composite layer 122, and a first composite layer 121 arranged along the width direction of the core layer 11. Alternatively, as shown in Figure 3, the composite aluminum foil may have a first composite layer 121, a second composite layer 122, a first composite layer 121, and a second composite layer 122 arranged along the width direction of the core layer 11, with the first composite layer 121 and the second composite layer 122 arranged alternately. It is understood that multiple first composite layers 121 and second composite layers 122 may be provided according to the requirements of the heat exchanger structure used, and this is not limited here.

[0047] In terms of 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%.

[0048] Specifically, the materials of the first composite layer 121 and the second composite layer 122 are aluminum alloys, and the Si content in the first composite layer 121 material is less than or equal to 1.2%. Si is the main impurity element in the aluminum alloy raw material. Si exists in the form of solid solution in Al and 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, when the composite layer material does not need to be welded, the content of Si element is controlled to be less than or equal to 1.2%. This can avoid intergranular corrosion caused by Si diffusion when there is too much Si, thereby improving the corrosion resistance of the composite aluminum foil.

[0049] The Si content of the second composite layer 122 is greater than or equal to 5% and less than or equal to 12%, facilitating welding with other components while ensuring the material's corrosion resistance. According to the Al-Si alloy phase diagram, when the Si content is less than 5%, the liquid phase is insufficient, making effective welding impossible. Therefore, a composite aluminum foil with a Si content greater than 5% is selected for the second composite layer 122 for bonding. However, when the Si content exceeds 12%, the excessive Si content can easily cause intergranular corrosion, reducing corrosion resistance. Alternatively, brazing can be used as the welding method.

[0050] The composite aluminum foil material in the embodiment of the present disclosure includes a core layer 11 and a composite layer 12. The composite layer 12 includes a staggered structure of a first composite layer 121 with an Si content of less than or equal to 1.2% and a second composite layer 122 with an Si content of greater than or equal to 5% and less than or equal to 12% formed in the width direction of the core layer 11. When the composite aluminum foil is applied 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 away from the heat exchange tube 2, the composite layer 12 material of the fin 1 adopts the first composite layer with an Si content of less than or equal to 1.2%. 121. The Si content in the material is reduced at positions where welding is not required, thereby reducing the overall Si content in the fin while realizing welding of the fin 1 with other components. Since Si is an element that increases the potential of aluminum alloys, Si enriched at the grain boundaries will cause corrosion along the grain boundaries. Intergranular corrosion is a highly destructive corrosion mode that will cause the material to lose strength and cause breakage and pulverization. The composite aluminum foil in this embodiment reduces the Si content while being able to achieve welding, reduces the probability of intergranular corrosion, improves the corrosion resistance of the composite aluminum foil, and improves the reliability of the material.

[0051] In some embodiments, the Si content in the material of the first composite layer 121 is 0.3-1.2% by mass.

[0052] 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%, and 1.1%; Si is the main impurity element in aluminum alloy raw materials. Si exists in Al in the form of solid solution, and has a certain solid solution strengthening effect on Al. Si is an element that increases the potential of Al alloy, but excessive Si will increase the probability of intergranular corrosion and reduce the corrosion resistance of aluminum alloy. Therefore, when the material does not need to realize the welding zone, the content of Si element is controlled to be greater than or equal to 0.3% and less than or equal to 1.2%. This can avoid intergranular corrosion caused by Si diffusion when there is too much Si, thereby improving the corrosion resistance of the composite aluminum foil.

[0053] 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%.

[0054] 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 the 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 in the alloy and improve the corrosion potential of the composite aluminum foil. The addition amount of Cu element in the material disclosed herein does not exceed 0.8%.

[0055] In some embodiments, the Si content in the material of the second composite layer 122 is 5.0-12.0% by mass.

[0056] 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.

[0057] 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%.

[0058] 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 the 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 in the alloy and improve the corrosion potential of the composite aluminum foil. The addition amount of Cu element in the material disclosed herein does not exceed 0.8%.

[0059] In some embodiments, the thickness of the composite layer 12 accounts for 6% to 15% of the thickness of the composite aluminum foil.

[0060] Specifically, the composite aluminum foil comprises a core layer 11 and a composite layer 12. The thickness of the composite layer 12, disposed on one side of the core layer 11, accounts for 6% to 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 composite layer 12 is too high, which easily causes intergranular corrosion. Therefore, setting the thickness of composite layer 12 to 6% to 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.

[0061] 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.

[0062] 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%.

[0063] 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 the influence of the two on the corrosion resistance and extrusion performance of the alloy, the Fe content range disclosed in this invention is between 0.01-0.5%.

[0064] 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 a high Ti content and the adjacent Al-based solid solution with a 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.

[0065] 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 with decreasing temperature, reaching approximately 0.45% at 300°C and 0.1% at room temperature. Due to 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 in the presence of slight supersaturation, it is difficult to form a second phase. Cu in the alloy increases strength and the corrosion potential of the composite aluminum foil. The amount of Cu added to the disclosed material does not exceed 0.8%.

[0066] The Zn content is 1.0-3.0%, and the maximum solid solubility of Zn in Al can reach 83.1% at 381°C. As the temperature decreases, the solid solubility continues to decrease, reaching about 32% at 277°C and about 5.6% at 125°C. Since Zn has a certain solid solution strengthening effect on Al, higher Zn will reduce the extrusion processing performance of the alloy, and considering that the effect of Zn on the reduction of Al corrosion potential is greater when the Zn content is about 3.00% or less, the amount of Zn added in the material disclosed herein does not exceed 3.00%. Since the potential of the fins used in the composite aluminum foil needs to be lower than that of the heat exchange tubes, at least 1% of Zn is added to ensure that the potential of the fins maintains a potential difference of at least 50mv with the heat exchange tubes. The amount of Zn added in the material disclosed herein is not less than 1.00%.

[0067] Si is the main impurity element in the raw materials of electrolytic aluminum. Si exists in Al in the form of solid solution and has a certain solid solution strengthening effect on Al. However, Si is an element that increases the potential of Al alloy. Excessive Si will reduce the corrosion resistance of aluminum alloy. Therefore, the Si content in the core layer 11 is less than 1.2%.

[0068] Therefore, the composite aluminum foil improves the overall material properties of the composite aluminum foil through the setting of the core layer 11 material, and reduces the Si content in the composite layer 12 through the setting of the composite layer 12. The Si content in the material is reduced while welding can be achieved, the probability of intergranular corrosion is reduced, and the corrosion resistance of the composite aluminum foil is further improved.

[0069] In some embodiments, as shown in Figures 4-6, 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, the second layer 1222 is farther away from the core layer 11 than the first layer 1221, and the first layer 1221 includes flux.

[0070] Specifically, as shown in Figures 4 and 5, 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 and lower sides of the core layer 11. Alternatively, as shown in Figure 6, 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 away 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.

[0071] In some embodiments, first layer 1221 includes a brazing flux and an Al-Si alloy, and second layer 1222 includes an Al-Si alloy. The Al-Si alloy is the same material as the second composite layer 122, with the brazing flux added to the first layer 1221. Alternatively, the brazing flux may be NOCOLOK brazing flux, which may be a brazing flux powder. The Al-Si alloy and the brazing flux powder are mixed under high pressure to form first layer 1221, i.e., a brazing flux mixed powder layer. First layer 1221 and second layer 1222 are then rolled together to form second composite layer 122.

[0072] The first layer 1221 of the second composite layer 122 of the composite aluminum foil includes a flux. The flux is mixed into the composite aluminum foil material, thereby avoiding the need to spray the flux separately to achieve welding when the composite aluminum foil needs to be welded with other components in subsequent applications, thereby reducing the processing steps; and by mixing the flux into the composite aluminum foil material, the flux can be distributed more evenly in the material, which can improve the welding quality; on the other hand, the flux is only included in the second composite layer 122 material that needs to be welded, thereby reducing the flux content in the overall composite aluminum foil material.

[0073] In this embodiment, the second composite layer 122 includes a first layer 1221 and a second layer 1222. The first layer 1221 includes a flux, and the second layer 1222 is located at the outermost layer in the thickness direction of the core layer 11. Since the second layer 1222 located at the outermost layer of the core layer 11 does not contain a flux, problems such as peeling and powdering of the composite aluminum foil after rolling can be avoided.

[0074] A dense oxide film is easily formed on the surface of aluminum and its alloys, and the oxide film has a high melting point. 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 composite layer 12 of the fin 1, that is, the flux layer, begins to melt, and the melted flux diffuses to the outside of the fin 1. During the diffusion process, the oxide film on the surface of the fin 1 and the heat exchange tube 2 is destroyed, and the fluidity of the second layer 1222, that is, the outermost flux-free layer of solder is 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.

[0075] 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 flux, while the first composite layer 121 does not include a flux layer. In this way, when the composite aluminum foil is applied to the fin 1, there is no flux residue on the surface of the fin 1. When used in a heat exchanger, a large amount of flux residue may cause problems such as flux breakage, white powder blowing, and odor during use. Such a setting can significantly reduce the flux residue and improve the appearance and reliability of the heat exchanger.

[0076] 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 adjacently arranged.

[0077] Specifically, as shown in Figures 4 and 5, there is one first layer 1221 and one second layer 1222 in the thickness direction of the core layer 11. As shown in Figure 6, there is one first layer 1221 and two second layers 1222 in the thickness direction of the core layer 11. The first layer 1221 and the second layer 1222 are adjacent to each other and cross-arranged in the thickness direction of the core layer 11. Of course, it can be understood that two or more first layers 1221 and two or more second layers 1222 can also be set, and there is no limitation here.

[0078] When a single first layer 1221 and a single second layer 1222 are provided, if the flux content in the first layer 1221 is too high, it may cause breakage during rolling, making it difficult to process. On the other hand, if the single first layer 1221 is on the inside, and the outermost layer of the fin 1 is the second layer 1222 without flux, the flux is not easily precipitated to the outside of the composite aluminum foil, which is not conducive to welding. Providing multiple first layers 1221 and multiple second layers 1222 cross-stacked in the thickness direction of the core layer 11 increases the fluidity of the solder, which is beneficial to improving welding performance. It also makes the flux mixed powder layer evenly distributed on the fin 1, making welding more uniform, effectively solving the problem of uneven flux flow, and improving welding quality.

[0079] In some embodiments, the thickness of first layer 1221 accounts for 5%-90% of the thickness of second composite layer 122. First layer 1221 comprises an Al-Si alloy and a flux. When the content of first layer 1221 is less than 5%, the flux content is insufficient and welding requirements cannot be achieved. When the content of first layer 1221 accounts for more than 90% of the thickness of composite layer 122, the flux is excessive, which may cause defects such as surface peeling and powder dispersion after rolling. Therefore, setting the thickness of first layer 1221 to 5%-90% of the thickness of second composite layer 122 improves the welding effect between the fin and other components when the composite aluminum foil is used in fins, improving welding quality and reliability.

[0080] In some embodiments, the composite layer 12 includes a third composite layer 123 . In the width direction of the core layer 11 , the third composite layer 123 is located between 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%.

[0081] Specifically, when processing the composite aluminum foil, the first composite layer 121 and the second composite layer 122 are adjacently arranged along the width direction of the core layer 11. During the rolling process of the composite aluminum foil processing, the adjacent first composite layer 121 and the second composite layer 122 may cross and penetrate each other, thereby forming a third composite layer 123 in the transition zone between the first composite layer 121 and the second composite layer 122. The third composite layer 123 has a structure as shown in Figure 3. The third composite layer 123 can be an irregular shape, and a third composite layer 123 may also be formed in other embodiments (not shown in the figure).

[0082] 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 content 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 the composite aluminum foil is reduced, and has good corrosion resistance.

[0083] The embodiment of the present disclosure also discloses a method for processing a composite aluminum foil for fins, comprising the following steps: providing an aluminum foil, forming a core layer 11 by at least melting, casting and surface cutting; forming a raw material for a first composite layer 121 by at least melting, casting, hot rolling and cutting, wherein the Si content in the first composite layer 121 is less than or equal to 1.2%; forming a raw material for a second composite layer 122 by at least melting, casting, hot rolling and cutting, wherein the Si content in the second composite layer 122 is greater than or equal to 5% and less than or equal to 12%, and first preparing the raw materials for the core layer 11, the first composite layer 121 and the second composite layer 122.

[0084] Optionally, the core layer 11 is composed of alloying elements within the following weight 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%, with the individual content of the remaining alloying elements not exceeding 0.05%, and the total content of the remaining alloying elements not exceeding 0.3%, with the balance being Al and inevitable impurities. Optionally, the first composite layer 121 is composed of alloying elements within the following weight percentage (wt.%) 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%, with the individual content of the remaining alloying elements not exceeding 0.15%, and the total content of the remaining alloying elements not exceeding 0.5%, with the balance being Al and inevitable impurities. Optionally, the second composite layer 122 is composed of alloy elements in the following mass percentage (wt.%) 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.

[0085] The raw material of the first composite layer 121 is placed on the core layer 11 , and the raw material of the second composite layer 122 is placed on the core layer 11 . The laminated core layer 11 and composite layer 12 are integrated by hot cladding rolling to form a rolled material.

[0086] 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 located on the same layer on the core layer 11. The first composite layer 121 and the second composite layer 122 are adjacently arranged along the width direction of the core layer 11. The thickness of the first composite layer 121 and the thickness of the second composite layer 122 are the same. The first composite layer 121 and the second composite layer 122 are alternately placed to form the composite layer 12.

[0087] In some embodiments, the first composite layer 121 may be one, two or more, and the second composite layer 122 may 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 on the core layer 11. For example, 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. Processing can be performed according to actual needs and is not limited here.

[0088] Then, the laminated core layer 11 and the composite layer 12 are integrated by hot cladding rolling to form a rolled material. It is understood that the composite layer 12 can be provided on both sides of the core layer 11 in the thickness direction, or it can be provided on only one side of the core layer 11 in the thickness direction. When the composite layer 12 is provided on both sides of the core layer 11 in the thickness direction, the composite layer 12, the core layer 11, and the composite layer 12 are provided in sequence, and the laminated core layer 11 and the composite layer 12 are integrated by hot cladding rolling to form a rolled material.

[0089] The rolled material is cold rolled, annealed and cut, and then processed into composite aluminum foil as required. The rolled material is cold rolled, annealed and cut, and then processed into two or more layers of composite aluminum foil according to different product sizes.

[0090] According to the method for processing composite aluminum foil for fins of this embodiment, a composite aluminum foil with good corrosion resistance can be obtained, and the processing is simple; the composite aluminum foil is used to process and form fins, and when the fins are applied to a heat exchanger, while the fins are welded to other components, the Si content in the fins is reduced, thereby improving the corrosion resistance of the fins, which is beneficial to improving the corrosion resistance of the heat exchanger.

[0091] In some embodiments, the composite aluminum foil is processed according to the structural requirements of the fins, such as by cutting to size, punching holes, or notching, so that it is processed into the required fins, which can meet the requirements of the heat exchanger and better connect with the heat exchange tube 2. Optionally, according to the structural requirements of the fins, designs such as windows can be added to improve the heat exchange capacity of the fins, or reinforcing rib structures can be added to improve the pressure resistance of the fins, which are not limited here.

[0092] In some specific embodiments, when forming the material of the second composite layer 122, a first layer 1221 containing a flux is formed by at least melting, casting, hot rolling and cutting, and the first layer 1221 includes a flux, and a second layer 1222 is formed by at least melting, casting, hot rolling and cutting, and the second layer 1222 does not contain a flux, and 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.

[0093] The first layer 1221 of the second composite layer 122 of the composite aluminum foil includes a flux. The flux is mixed into the composite aluminum foil material, thereby avoiding the need to spray the flux separately to achieve welding when the composite aluminum foil needs to be welded with other components in subsequent applications, thereby reducing the processing steps; and by mixing the flux into the composite aluminum foil material, the flux can be distributed more evenly in the material, which can improve the welding quality; on the other hand, the flux is only included in the second composite layer 122 material that needs to be welded, thereby reducing the flux content in the overall composite aluminum foil material.

[0094] It is understandable that, in order to meet the requirements of fin materials, multiple first layers 1221 and multiple second layers 1222 can be processed, and 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 other embodiments, the first layer 1221, the second layer 1222, and then the first layer 1221 and the second layer 1222 are stacked and rolled to form the second composite layer 122; or, in 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 is not limited by the present disclosure. A multi-layer first layer 1221 and a multi-layer second layer 1222 are stacked in the thickness direction of the core layer 11 to increase the fluidity of the solder, which is beneficial to improving the welding performance, and makes the flux mixed powder layer evenly distributed on the composite aluminum foil, so that the fin using the composite aluminum foil can be more uniform when welded with other components, effectively solving the problem of uneven flux flow and improving welding quality.

[0095] It should be noted here that during the processing, when the first layer 1221 and the second layer 1222 are multiple layers, the second layer 1222 is located at the outermost side of the core layer 11 in the direction of the core layer thickness. Since the second layer 1222 does not contain flux, problems such as peeling and powdering of the composite aluminum foil after rolling can be avoided, which affects the appearance and welding quality.

[0096] The present disclosure also provides a fin, the fin material includes the above-mentioned composite aluminum foil, the fin 1 includes a plurality of through holes or through slots, and the plurality of through holes or through slots are spaced apart along the length direction of the fin 1. In the width direction of the fin 1, near the through holes or through slots, the material of the fin includes a second composite layer 122, and away from the through holes or through slots, the material of the fin includes a first composite layer 121.

[0097] Specifically, the material of the fin includes the above-mentioned composite aluminum foil. The fin 1 uses the above-mentioned composite aluminum foil as a raw material and is formed by processing the above-mentioned composite aluminum foil according to the structural requirements of the fin 1. The composite aluminum foil is processed and formed using the above-mentioned composite aluminum foil processing method. As shown in Figures 7a-12b, 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 1 are used to adapt to the installation of 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. The thickness direction of the fin 1 is consistent with the thickness direction of the core layer 11.

[0098] Along the width direction x of the fin 1, near the through-hole 13 or through-slot 14 of the fin 1, the composite layer material of the fin 1 includes the second composite layer 122, and away from the through-hole 13 or through-slot 14, the composite layer material of the fin 1 includes the first composite layer 121. It can be understood that, along 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 and away from the through-hole 13 or through-slot 14.

[0099] In this embodiment, the through hole 13 or the through groove 14 of the fin 1 needs to be adapted to connect the heat exchange tube 2, and the fin 1 needs to be connected to the heat exchange tube 2 by welding or the like. In order to achieve welding of the fin 1 and the heat exchange tube 2, the material of the fin 1 at the through hole 13 or the through groove 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 part of the fin 1 away from the through hole 13 or the through groove 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 reducing the Si content of the composite layer 12 in the fin, reducing intergranular corrosion caused by Si diffusion, and improving the corrosion resistance of the fin. Therefore, the design of the fin disclosed in the present invention can reduce intergranular corrosion and improve the corrosion resistance of the fin while achieving welding. Furthermore, after the corrosion resistance of the fin is improved, the fin is not easily damaged, thereby avoiding the damage of the fin affecting the heat exchange of the heat exchanger on the air side. 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 1 is also enhanced, thereby improving the heat exchange performance of the heat exchanger.

[0100] In some embodiments, as shown in Figures 7a, 7b, 10a, and 10b, 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 1 is the second composite layer 122, and a plurality of through holes 13 are arranged at intervals along the length direction y of the fin 1. In the length direction y of the fin 1, the composite layer material of the fin 1 near the through hole 13 includes the second composite layer 122, and away from the through hole 13, the composite layer material of the fin 1 includes the first composite layer 121. The first composite layer 121 and the second composite layer 122 are adjacently arranged in the width direction x of the fin 1.

[0101] In this embodiment, the fin material includes a composite layer 12 on both sides of the fin 1 in the thickness direction. It is understood that the composite layer 12 may also be included on only one side of the fin 1 in the thickness direction. When the composite layer 12 is only provided on one side of the fin 1 in the thickness direction, the fin 1 can be welded to the heat exchange tube 2 connected to the side with the composite layer 12, and the overall Si content of the composite layer 12 is reduced, which can further improve the corrosion resistance of the fin. The multiple through-holes 13 of the fin 1 are arranged at intervals along the length direction y of the fin 1. Accordingly, the first composite layer 121 and the second composite layer 122 adjacent to each other in the width direction of the fin 1 also extend along the length direction y of the fin 1.

[0102] In some embodiments, as shown in Figures 12a and 12b, the fin 1 includes a plurality of through slots 14, and near the through slots 14, the fin material includes a second composite layer 122, and the plurality of through slots 14 are arranged at intervals along the length direction y of the fin 1. In the length direction x of the fin 1, the fin material near the through slots 14 includes the second composite layer 122, and away from the through slots 14, the fin material includes a first composite layer 121, and 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.

[0103] In this embodiment, the fin material on one side of the fin 1 in the thickness direction includes a composite layer 12. The fin 1 can be welded to the heat exchange tube 2 connected to the side with the composite layer 12, further reducing the overall Si content of the composite layer 12 and further improving the corrosion resistance of the fin. It is understood that the fin material on both sides of the fin 1 in the thickness direction can also include a composite layer 12. The multiple through-slots 14 of the fin 1 are arranged at intervals along the length direction y of the fin 1. Accordingly, 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.

[0104] In some embodiments, the fin 1 includes a first side 1 a and a second side 1 b oppositely disposed along a width direction of the fin 1 , and the material of the first side 1 a and / or the second side 1 b of the fin 1 includes a first composite layer 121 .

[0105] Specifically, as shown in Figures 7a, 10a, and 12a, the fin 1 includes a first side 1a and a second side 1b in the width direction x, i.e., the left-right direction in the figure. The material of the fin 1 near the first side 1a and / or the second side 1b includes a first composite layer 121. It is understood that the first composite layer 121 material may be included only near the first side 1a of the fin 1, only near the second side 1b of the fin 1, or both near the first side 1a and near the second side 1b of the fin 1.

[0106] When the fin is used in the heat exchanger, during the operation of the heat exchanger 100, air will flow through the heat exchanger 100 along the width direction of the fin 1. On both sides of the width direction of the fin 1, especially on the windward side, the wind volume is large and the heat exchange performance is better. Therefore, the corrosion resistance of the fin 1 on the windward side needs to be better. The fin 1 is arranged near the first side 1a or near the second side 1b, and the fin material includes a first composite layer 121, or the fin 1 includes the first composite layer 121 material near the first side 1a and near the second side 1b of the fin 1, and the Si content in the first composite layer 121 is less than or equal to 1.2%. As a result, intergranular corrosion of the fin 1 on the first side 1a and / or the second side 1b caused by the diffusion of Si elements can be reduced, and corrosion or crushing of the fins at the edges can be avoided, which affects the heat exchange performance of the heat exchanger, thereby improving the heat exchange performance and reliability of the heat exchanger.

[0107] In some embodiments, along the width direction of the fin 1 , a distance between an edge of the through hole 13 or the through slot 14 of the fin 1 and an edge of the adjacent first composite layer 121 is t, and the range of t is 0-10 mm.

[0108] Specifically, as shown in Figures 7a, 10a and 12a, along the width direction x of the fin 1, that is, the left and right direction, the distance between the edge of the through hole 13 or the through groove 14 of the fin 1 and the edge of the adjacent first composite layer 121 is t, and the range of t is 0-10 mm. The through-holes 13 or through-slots 14 on the fin 1 are used to insert the heat exchange tube 2 and weld it to the fin 1. The fin material near the through-holes 13 or through-slots 14 includes a second composite layer 122. Setting t greater than 0 allows the fin 1 to include a certain distance of the second composite layer 122 material in the width direction of the fin 1. The Si content of the second composite layer 122 material is greater than or equal to 5% and less than or equal to 12%, thereby achieving welding of the fin 1 to the heat exchange tube 2. However, when t is greater than 10 mm, the width of the second composite layer 122 material in the width direction x of the fin 1 is too large, resulting in the width of the first composite layer 121 material in the fin 1 in the width direction x of the fin 1 being too small. The Si content of the first composite layer 122 material is less than or equal to 1.2%, which increases the Si content in the entire fin and is not conducive to improving the corrosion resistance of the fin. Therefore, setting t greater than 0 and less than 10 mm is beneficial to further improve the corrosion resistance of the fin while ensuring welding quality, thereby improving the corrosion resistance of the heat exchanger.

[0109] Furthermore, at the through holes 13 or through grooves 14 on both sides of the fin 1 in the width direction, the adjacent first composite layer 121 material is close to the first side 1a, or close to 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 1 is too large, and the size of the fin 1 in its width close to the first side 1a, or the second side 1b is too small. In this way, the fin 1 is prone to damage or crushing at the position close to the first side 1a or the second side 1b. Damage or crushing of the edge of the fin 1 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 welding quality, improving corrosion resistance of the heat exchanger, and improving the heat exchange performance of the heat exchanger.

[0110] A fin for a heat exchanger according to a specific embodiment of the present disclosure is described below.

[0111] As shown in Figure 7a, the fin 1 includes a plurality of through holes 13, and three rows of through holes 13 are arranged along the width direction of the fin 1. The three rows of through holes 13 are arranged at intervals along the width direction of the fin 1, and the multiple through holes 13 in each row are arranged at intervals along the length direction of the fin 1. In Figure 7a, the width direction of the fin 1 is the x direction, that is, the left-right direction in Figure 7a, and the length direction of the fin 1 is the y direction, that is, the up-down direction in Figure 7a.

[0112] As shown in Figure 7b, 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 1. The z direction in Figure 7b 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 the composite layer 12 can also be provided on only one side of the fin 1 in the thickness direction.

[0113] 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 1. The left and right directions in Figure 7b are the width directions of the fin 1. The first composite layer 121 and the second composite layer 122 are located in the same layer in the thickness direction of the fin 1, and the adjacent layer of the first composite layer 121 and the second composite layer 122 is the core layer 11 of the fin 1.

[0114] In the width direction of the fin 1, the material of the fin near the through hole 13 includes a second composite layer 122. The through hole 13 on the fin 1 facilitates the insertion of the heat exchange tube 2 and is welded to the heat exchange tube 2; the material of the fin away from the through hole 13 includes a first composite layer 121, thereby forming a first composite layer 121 and a second composite layer 122 of the composite layer 12 of the fin 1 adjacent to each other in the width direction of the fin 1; and on both sides of the width direction of the fin 1, the material of the fin 1 includes the first composite layer 121.

[0115] For ease of understanding, Figure 7b illustrates the different composite layer materials of the fin in Figure 7a at different locations along the thickness direction z of the fin material. In this embodiment, the composite layers 12 of fin 1 are arranged in sequence along the width of fin 1: first composite layer 121, second composite layer 122, first composite layer 121, second composite layer 122, first composite layer 121, second composite layer 122, and first composite layer 121. Fin 1's multiple through-holes 13 are spaced apart along the length of fin 1. To facilitate welding, first composite layer 121 and second composite layer 122 also extend along the length of fin 1.

[0116] Fin 1's second composite layer near through-hole 13 contains a Si content of 5% or greater and 12% or less, facilitating welding to heat exchange tube 2. The first composite layer, located away from through-hole 13, contains a Si content of 1.2% or less, reducing the overall Si content of the fin, thereby reducing intergranular corrosion and improving the fin's corrosion resistance. Furthermore, on both sides of the fin's width (left-right direction), the composite layer comprises a first composite layer 121, with a Si content of 1.2% or less, further enhancing the fin's corrosion resistance.

[0117] A fin for a heat exchanger according to another specific embodiment of the present disclosure is described below.

[0118] As shown in FIG10 a , the fin 1 includes a plurality of through holes 13 , which are arranged at intervals along the length direction y of the fin 1 , and a row of through holes is arranged along the width direction x of the fin 1 .

[0119] As shown in Figure 10b, 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 1. The thickness direction of the fin in Figure 10b is the up and down direction. There are composite layers 12 on both sides of the thickness direction of the core layer 11. Of course, the composite layer 12 can also be located on one side of the thickness direction of the core layer 11.

[0120] 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 1. In Figure 10b, the width direction of the fin 1 is the left-right direction. Along the width direction of the fin 1, the material of the fin close to 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 2 and welding with the heat exchange tube 2; the fin material away from the through hole 13 of the fin 1 includes the first composite layer 121, thereby forming the first composite layer 121, the second composite layer 122 and the first composite layer 121 of the fin 1 arranged at intervals in the width direction of the fin 1; on both sides of the width direction of the fin 1, the material of the fin includes the first composite layer 121.

[0121] For ease of understanding, Figure 10b illustrates the different composite layer 12 materials of the fin in Figure 10a at different locations along the thickness of the fin material. In this embodiment, the first composite layer 121, second composite layer 122, and first composite layer 121 of the composite layer 12 of fin 1 are arranged sequentially along the width of fin 1. The Si content of the second composite layer near the through-hole 13 of fin 1 is greater than or equal to 5% and less than or equal to 12%, facilitating welding to heat exchange tube 2. The Si content of the first composite layer away from the through-hole 13 is less than or equal to 1.2%, which reduces the Si content while enabling welding, thereby reducing intergranular corrosion and improving the corrosion resistance of the fin.

[0122] A fin for a heat exchanger according to another specific embodiment of the present disclosure is described below.

[0123] As shown in Figure 12a, the fin 1 includes a plurality of through slots 14, which are arranged at intervals along the length direction of the fin 1. The length direction of the fin 1 is the y direction in Figure 12a, that is, the up and down direction. A row of through slots 14 is arranged along the width direction x direction of the fin 1.

[0124] As shown in Figure 12b, 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 1. The thickness direction of the fin 1 in Figure 12b is the up and down direction. The composite layer 12 is provided on one side of the thickness direction of the fin 1. When the composite layer 12 is provided on only one side of the thickness direction of the fin 1, the fin 1 can be welded to the heat exchange tube 2 connected to 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.

[0125] 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 1. The width direction of the fin 1 in Figure 12b is the left-right direction. Along the width direction of the fin 1, the material of the fin near the through groove 14 includes the second composite layer 122. The through groove 14 on the fin 1 facilitates the installation of the heat exchange tube 2. The heat exchange tube 2 is adapted to be installed in the through groove 14 and welded to the fin 1; the fin material away from the through groove 14 of the fin 1 includes the first composite layer 121, thereby forming the first composite layer 121, the second composite layer 122 and the first composite layer 121 of the fin 1 in the width direction x of the fin 1, and the material of the fin includes the first composite layer 121 on both sides of the width direction (left-right direction) of the fin 1.

[0126] For ease of understanding, Figure 12b illustrates the different composite layers 12 of the fin in Figure 12a at different locations along the thickness direction z of the fin material. In this embodiment, the first composite layer 121, the second composite layer 122, and the first composite layer 121 of the composite layer 12 of fin 1 are arranged in sequence. The Si content of the second composite layer near the through-slot 14 of fin 1 is greater than or equal to 5% and less than or equal to 12%, facilitating welding connection with the heat exchange tube 2. The Si content of the first composite layer away from the through-slot 14 is less than or equal to 1.2%, which reduces the Si content while enabling welding, thereby reducing intergranular corrosion and improving the corrosion resistance of the fin.

[0127] In related art, heat exchange tubes and fins are connected by tube expansion. During this process, a gap exists between the tubes and fins, resulting in excessive thermal resistance between the tubes and fins and reducing the heat exchange performance of the heat exchanger. To reduce the thermal resistance between the tubes and fins and improve heat exchange performance, the tubes and fins are connected by welding. Brazing is typically performed using an Al-Si-based alloy. However, Si enrichment at the grain boundaries during welding can cause corrosion along these boundaries, resulting in intergranular corrosion, which can affect the reliability of the material and, consequently, the reliability and heat exchange performance of the heat exchanger.

[0128] The present disclosure discloses a heat exchanger. As shown in FIG8 , 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. The heat exchange tube 2 is 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 1.

[0129] Heat exchanger 100 also includes fins, which utilize the aforementioned fins. As shown in Figures 7a-12b, fin 1 includes a plurality of through-holes 13 or through-slots 14, which are spaced apart along the length of fin 1. Along the width of fin 1, near the through-holes 13 or through-slots 14, the composite material of fin 1 includes a second composite layer 122, while away from the through-holes 13 or through-slots 14, the composite material of fin 1 includes a first composite layer 121. The length direction of fin 1 is the y-direction in the figures, i.e., the vertical direction, and the width direction of fin 1 is the x-direction in the figures, i.e., the left-right direction.

[0130] The heat exchange tubes 2 are adapted to be mounted in the through-holes 13 or through-slots 14, and the fins 1 and heat exchange tubes 2 are welded together via the second composite layer 122 of the fins 1. Specifically, as shown in Figures 7a and 10a, the fins 1 include multiple through-holes 13, into which the heat exchange tubes 2 are inserted and welded together. As shown in Figures 11 and 12a, the fins 1 include multiple through-slots 14, into which the heat exchange tubes 2 are adapted to be mounted, and into which the fins 1 and heat exchange tubes 2 are welded together. The fins 1 and heat exchange tubes 2 are welded together via the second composite layer 122 of the fins 1. Optionally, the welding method is brazing.

[0131] In this embodiment, the heat exchange tube 2 needs to be adapted and connected at the through hole 13 or the through groove 14 near the fin 1, and the fin 1 needs to be connected to the heat exchange tube 2 by welding or other means. In order to achieve welding of the fin 1 and the heat exchange tube 2, the material of the fin 1 at the through hole 13 or the through groove 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 part of the fin 1 away from the through hole 13 or the through groove 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 reducing the Si content in the fin and avoiding intergranular corrosion caused by Si diffusion.

[0132] The heat exchanger disclosed herein adopts the above-mentioned fins, which can reduce the Si content in the fins while achieving welding with the heat exchange tubes, 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 help to increase the service life of the heat exchanger. Furthermore, after the corrosion resistance of the fins is improved, the fins are not easily damaged, avoiding the damage of the fins affecting the heat exchange of the heat exchanger on the air side, and improving the heat exchange performance of the heat exchanger.

[0133] It can be understood that the heat exchanger 100 can be provided with two or more rows of heat exchange tubes 2 along the width direction x of the fin 1. In the embodiment shown in Figure 7a, when multiple rows of heat exchange tubes 2 are provided, the fin 1 is provided with multiple rows of through holes 13 along its width direction x. The composite layer material of the fin 1 in its width direction can 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 in an alternating manner to adapt to different heat exchanger structures, which is not limited here.

[0134] It should be noted that, in this disclosure, relational terms such as "first" and "second" are merely used to distinguish one entity or unit from another, and do not necessarily require or imply any actual relationship or order between these entities or units. Furthermore, in this document, "plurality" means at least two, unless otherwise specifically defined.

[0135] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and features of different embodiments or examples, unless they are mutually inconsistent.

[0136] Although the embodiments of the present disclosure have been shown and described above, it should be understood that the above embodiments are illustrative and should not be construed as limiting the present disclosure. Persons skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present disclosure. Any modifications, equivalent substitutions, improvements, and the like made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure.

Claims

1. A composite aluminum foil for fins, the composite aluminum foil material comprising: 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 disposed 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 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%.

2. The composite aluminum foil for fins according to claim 1, wherein, 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 or 2, wherein, 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 to 3, wherein, 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, wherein, 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, wherein, 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 adjacent to each other.

7. The composite aluminum foil for fins according to any one of claims 1-3, wherein, 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 a composite aluminum foil for fins, comprising the following steps: Providing an aluminum foil, the aluminum foil forming a 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, wherein the Si content in the first composite layer is 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, wherein the Si content in the second composite layer is 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 adjacent to each other 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 a composite layer, and integrally forming the laminated core layer and the composite layer by hot cladding rolling, thereby forming 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, wherein, 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, the fin material including the composite aluminum foil according to any one of claims 1-7, the fin including a plurality of through holes or through grooves, the plurality of through holes or through grooves being 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 including the second composite layer, and away from the through holes or through grooves, the material of the fin including the first composite layer.

11. The fin according to claim 10, wherein, The fin includes a first side and a second side arranged opposite to each other in the width direction of the fin, and the material of the fin near the first side and / or the second side includes the first composite layer.

12. The fin according to claim 10 or 11, wherein 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, the heat exchanger including a first pipe, a second pipe, and a plurality of heat exchange pipes, the first pipe and the second pipe being arranged at intervals, one end of the heat exchange pipe being connected to the first pipe, and the other end of the heat exchange pipe being connected to the second pipe to connect 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 being adaptively installed in the through holes or through grooves, and the heat exchange pipes and the fins being welded through the second composite layer.

Images