Rare earth-containing aluminum alloy and preparation method therefor, and heating, ventilation and air conditioning device

Abstract

The present application discloses a rare earth-containing aluminum alloy and a preparation method therefor, and a heating, ventilation and air conditioning device. The rare earth-containing aluminum alloy comprises the following components in percentage by mass: 0.05%-0.30% of Fe, 0.05%-0.25% of Si, 0.80%-1.6% of Mn, 0.05%-0.45% of Cu, 0.01%-0.15% of Ti, 0.10%-0.20% of Zr, 0.05%-0.30% of rare earth, and the balance being Al and impurity elements, wherein the sum of the mass percentages of the impurity elements is less than or equal to 0.20%. In the present application, the selection of elements of an aluminum alloy is optimized to implement uniform distribution of intermetallic compounds of the aluminum alloy, such that the corrosion potential of an aluminum matrix is increased, and the corrosion potential of harmful intermetallic compounds is decreased, thereby reducing the corrosion potential difference between an aluminum alloy matrix and the intermetallic compounds, and improving the corrosion resistance. Additionally, the rare earth-containing aluminum alloy of the present application can achieve a corrosion depth of 150 μm or less after exposed for 12 days in sea water acetic acid test (SWAAT) per ASTM G85 standard.

Description

Rare earth-containing aluminum alloy, preparation method thereof and heating and ventilation equipment

[0001] Related applications

[0002] The present application claims priority to the following Chinese patent application:

[0003] Application No. 202410653115.4, filed on May 23, 2024, and entitled "Rare earth-containing aluminum alloy, preparation method thereof and heating and ventilation equipment";

[0004] The above patent is hereby incorporated by reference in its entirety. TECHNICAL FIELD

[0005] The present application relates to the technical field of aluminum alloys, and in particular to a rare earth-containing aluminum alloy, a preparation method thereof and a heating and ventilation equipment. BACKGROUND

[0006] As one of the widely used metal materials, aluminum alloys are increasingly used in key components of heating and ventilation equipment such as heat exchange tubes and fins of heat exchangers. The main heat exchange components of traditional heating and ventilation equipment are generally made of copper, which is heavy and costly, and is not conducive to the lightweight and energy saving of heat exchangers. Aluminum alloys have the characteristics of low density, good thermal conductivity and good mechanical properties, and their price is lower than that of copper, so they have been widely used in heat exchange structures. Aluminum alloys are relatively active, and a dense oxide film is formed on the surface of aluminum alloys. In ordinary atmospheric environment, neutral solution and weak acid solution, the oxide film can protect the aluminum alloy matrix to a certain extent. However, in the application process, aluminum alloys are often in a relatively complex environment, such as wind and sand, humidity, drought, etc. Especially in the humid natural environment, the oxide film on the surface of aluminum alloy will be damaged by erosive ions (such as Cl-), which will initiate pitting and gradually expand to cause material corrosion failure, so the corrosion resistance of aluminum alloys needs to be improved to meet different application scenarios.

[0007] The wrought aluminum alloy (for example, 3001, 3006, and the like 3XXX series aluminum alloy) in the related art has good ductility, formability, weldability, and corrosion resistance, and is widely used in the field of heat exchange. However, the wrought aluminum alloy in the related art has low strength, and part of the alloying elements in the aluminum alloy form inhomogeneous intermetallic compounds, part of the intermetallic compounds have a large difference in corrosion potential from the aluminum alloy matrix, and are prone to cause micro-electrode corrosion. In addition, the corrosion resistance of the aluminum alloy is mainly attributed to different microstructure compositions, in which the alloying elements contained in the aluminum alloy play a decisive role. Various intermetallic compounds generated by the alloying elements can cause significant local corrosion damage to the aluminum alloy. Compared with the aluminum alloy matrix, the intermetallic compounds generated by the alloying elements in the aluminum alloy can be cathode or anode, and the greater the difference in corrosion potential between the intermetallic compounds and the aluminum alloy matrix, the more prone the aluminum alloy is to local corrosion. Therefore, how to modify the intermetallic compound phase in the aluminum alloy is a key problem to improve the corrosion resistance of the aluminum alloy. SUMMARY

[0008] The embodiments of the present application provide a rare earth-containing aluminum alloy, a preparation method thereof, and a heating and ventilation device. The elements of the aluminum alloy are optimized to realize uniform distribution of intermetallic compounds in the aluminum alloy, so as to solve the problems existing in the prior art to some extent.

[0009] In a first aspect, the present application provides a rare earth-containing aluminum alloy, comprising the following components by mass fraction: Fe 0.05% to 0.30%, Si 0.05% to 0.25%, Mn 0.80% to 1.6%, Cu 0.05% to 0.45%, Ti 0.01% to 0.15%, Zr 0.10% to 0.20%, rare earth 0.05% to 0.30%, and the balance of Al and impurity elements, wherein the total mass percentage content of the impurity elements is less than or equal to 0.20%.

[0010] In some exemplary embodiments, the mass percentage content of Cu is 0.10% to 0.35% based on the mass of the rare earth-containing aluminum alloy.

[0011] In some exemplary embodiments, the rare earth includes at least one of La, Ce, Y, Nd, Sm, and Yb; and the total mass percentage of each element of the rare earth is 0.10% to 0.25% based on the mass of the rare earth-containing aluminum alloy.

[0012] In some exemplary embodiments, the rare earth-containing aluminum alloy comprises the following components by mass fraction: Fe 0.05% to 0.20%, Si 0.05% to 0.15%, Mn 0.80% to 1.10%, Cu 0.15% to 0.35%, Ti 0.01% to 0.15%, Zr 0.10% to 0.20%, rare earth 0.10% to 0.25%, and the balance of Al and impurities, wherein the total mass fraction of the impurities is less than or equal to 0.20%.

[0013] In a second aspect, the present application provides a method for preparing a rare earth-containing aluminum alloy, comprising:

[0014] providing pre-prepared raw materials of pure aluminum ingot, aluminum-M intermediate alloy, aluminum-rare earth intermediate alloy, refining agent, and refining agent, M including at least one of Fe, Si, Mn, Cu, Ti, and Zr, and the mass fraction of each element in the pre-prepared raw materials is as follows: Fe 0.05% to 0.30%, Si 0.05% to 0.25%, Mn 0.80% to 1.6%, Cu 0.05% to 0.45%, Ti 0.01% to 0.15%, Zr 0.10% to 0.20%, rare earth 0.05% to 0.30%, and the balance of Al and impurities, wherein the total mass fraction of the impurities is less than or equal to 0.20%;

[0015] adding the pure aluminum ingot into a smelting furnace to perform a first-stage hot melting treatment to obtain an aluminum melt;

[0016] adding the aluminum-M intermediate alloy into the aluminum melt to perform a second-stage hot melting treatment to obtain an aluminum alloy melt;

[0017] adding the aluminum-rare earth intermediate alloy into the aluminum alloy melt to perform a third-stage hot melting treatment to obtain a rare earth-containing aluminum alloy melt;

[0018] adding the refining agent into the rare earth-containing aluminum alloy melt to perform a refining treatment to obtain a refined aluminum alloy melt;

[0019] adding the refining agent into the refined aluminum alloy melt to perform a refining treatment to obtain a refined aluminum alloy melt;

[0020] adding the refining agent into the refined aluminum alloy melt to perform a refining treatment to obtain a refined aluminum alloy melt;

[0021] In some exemplary embodiments, the aluminum-M intermediate alloy includes at least one of aluminum-manganese intermediate alloy, aluminum-copper intermediate alloy, aluminum-zirconium intermediate alloy, aluminum-iron intermediate alloy, aluminum-silicon intermediate alloy, and aluminum-titanium intermediate alloy.

[0022] In some exemplary embodiments, the aluminum-rare earth master alloy includes at least one of aluminum-lanthanum master alloy, aluminum-cerium master alloy, aluminum-yttrium master alloy, aluminum-neodymium master alloy, aluminum-samarium master alloy, and aluminum-ytterbium master alloy.

[0023] In some exemplary embodiments, the refining agent includes at least one of aluminum-titanium-boron master alloy, aluminum-titanium master alloy, and aluminum-titanium-boron-rare earth master alloy.

[0024] In some exemplary embodiments, the refining agent includes at least one of KCl, NaCl, Na3AlF6, Na2SiF6, CaF2, and C2Cl6.

[0025] In some exemplary embodiments, before performing the first stage of hot melting treatment, the process further includes: preheating the pure aluminum ingot, aluminum-M master alloy, aluminum-rare earth master alloy and refining agent, wherein the temperature of the preheating treatment is T0 and the time is t0, wherein 180℃≤T0≤220℃ and 1h≤t0≤5h.

[0026] In some exemplary embodiments, the temperature of the molten aluminum is T1, which satisfies: 720℃≤T1≤750℃.

[0027] In some exemplary embodiments, the temperature of the aluminum alloy melt is T2, which satisfies: 720℃≤T2≤750℃.

[0028] In some exemplary embodiments, the temperature of the rare earth aluminum alloy melt is T3, and T3 satisfies: 700℃≤T3≤730℃.

[0029] In some exemplary embodiments, the refining process includes: at T a Under certain temperature conditions, the refining agent is added to the rare earth-containing aluminum alloy melt, and refining is carried out for a first time t. m And let it stand for a second time t n Afterwards, the refined aluminum alloy melt is obtained by removing the slag; wherein, 710℃≤T a ≤740℃, 0.1h≤t m ≤0.25h, 0.15h≤t n ≤0.35h;

[0030] In some exemplary embodiments, the refinement process includes: in T b Under certain temperature conditions, a refining agent is added to the refined aluminum alloy melt, and the refining process is carried out for a third time t. h After slag removal, the refined aluminum alloy melt is obtained; wherein, 700℃≤T b ≤740℃, 0.15h≤t h≤0.5h.

[0031] In some example embodiments, the homogenization treatment has a temperature of T j and a time of t j , wherein 580℃≤T j ≤620℃ and 10h≤t j ≤14h.

[0032] In some example embodiments, the extrusion treatment has a die temperature of T i and an extrusion speed of V i , wherein 460℃≤T i ≤510℃ and 20m / min≤V i ≤25m / min.

[0033] In a third aspect, example embodiments provide a heating and ventilation device, comprising an aluminum alloy structure, the aluminum alloy structure comprising at least one of an aluminum alloy heat exchange component and an aluminum alloy pipe, the aluminum alloy structure being made of an aluminum alloy as described above.

[0034] In some example embodiments, the heating and ventilation device satisfies at least one of the following conditions:

[0035] (1) the aluminum alloy heat exchange component has a tensile strength A, A satisfying 90MPa≤A≤108Mpa;

[0036] (2) the aluminum alloy heat exchange component has a yield strength B, B satisfying 35MPa≤B≤50Mpa;

[0037] (3) the aluminum alloy heat exchange component has an elongation C, C satisfying 45%≤C≤55%.

[0038] In some example embodiments, the heating and ventilation device comprises a plurality of functional components, the plurality of functional components comprising a heat exchanger, the heat exchanger comprising at least one of the aluminum alloy heat exchange component, the aluminum alloy heat exchange component having a heat exchange channel inside for a heat exchange medium to flow through.

[0039] In some example embodiments, the heat exchanger comprises:

[0040] a plurality of flow guide pipes;

[0041] at least one flow collecting pipe, each of the flow collecting pipes having an internal passage in communication with internal passages of the plurality of flow guide pipes to collect and distribute the heat exchange medium;

[0042] at least one adapter pipe, each of the flow collecting pipes having an internal passage in communication with an internal passage of the at least one adapter pipe for the heat exchange medium to enter and exit the flow collecting pipe through the adapter pipe;

[0043] At least one pipe of the at least one manifold, the plurality of flow guide pipes and the at least one adapter pipe is the aluminum alloy pipe.

[0044] In some exemplary embodiments, at least part of the aluminum alloy heat exchange pipes are heat exchange round pipes; and / or, at least part of the aluminum alloy heat exchange pipes are heat exchange flat pipes.

[0045] In some exemplary embodiments, the HVAC device comprises a plurality of functional components and at least one aluminum alloy pipe, and at least two of the functional components are connected by the aluminum alloy pipe.

[0046] In some exemplary embodiments, the HVAC device comprises an indoor unit, an outdoor unit and a plurality of connecting pipes connecting the indoor unit and the outdoor unit.

[0047] The indoor unit comprises a part of the functional components and a plurality of indoor pipes connecting the functional components.

[0048] The outdoor unit comprises another part of the functional components and a plurality of outdoor pipes connecting the functional components.

[0049] At least one of the plurality of connecting pipes, the plurality of indoor pipes and the plurality of outdoor pipes is the aluminum alloy pipe.

[0050] The rare earth-containing aluminum alloy, the preparation method thereof and the HVAC device based on the embodiments of the present application have at least the following beneficial effects:

[0051] (1) By adding a trace amount of rare earth elements, the hydrogen content in the aluminum melt can be significantly reduced, the porosity and the porosity of the processed aluminum alloy can be reduced, and the inclusions and harmful elements can be reduced, thereby achieving the effects of degassing refining and purifying the melt.

[0052] (2) By controlling the Cu content in the aluminum alloy and the solid solution degree of Cu in the aluminum alloy matrix, the corrosion potential of the aluminum alloy matrix is improved, and the pitting resistance is enhanced. The rare earth element RE can form complex intermetallic compounds with impurities such as Mn, Fe and Si in the aluminum alloy matrix, which can spheroidize the intermetallic compounds, and the difference in corrosion potential between the intermetallic compounds containing the rare earth element and the aluminum alloy matrix is further reduced, thereby reducing the driving force of micro-electricity corrosion and reducing the tendency of local corrosion.

[0053] (3) The addition of the rare earth element RE refines the structure of the aluminum alloy, makes the intermetallic compounds in the aluminum alloy distribute uniformly, improves the pitting resistance and the mechanical properties, and has excellent processing performance. BRIEF DESCRIPTION OF DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0055] Fig. 1 is a perspective structural schematic view of the connection of the manifold, the flow guide pipe and the adapter pipe of the heat exchanger according to an embodiment of the present application;

[0056] Fig. 2 is a transverse sectional view of the flow guide pipe being a heat exchange flat pipe according to an embodiment of the present application;

[0057] Fig. 3 is a perspective structural schematic view of the connection of the flow guide pipe and the adapter pipe of the heat exchanger according to an embodiment of the present application;

[0058] Fig. 4 is a transverse sectional view of the flow guide pipe being a heat exchange round pipe according to an embodiment of the present application;

[0059] Fig. 5 is a longitudinal sectional view of the flow guide pipe provided with multiple fins according to an embodiment of the present application;

[0060] Fig. 6 is a longitudinal sectional view of the fin provided with an abutting groove according to an embodiment of the present application;

[0061] Fig. 7 is a schematic view of the connection of the outdoor unit and the pipeline of the outdoor unit according to an embodiment of the present application;

[0062] Fig. 8 is a microstructure diagram of the rare earth-containing aluminum alloy prepared in Example 3;

[0063] Fig. 9 is a microstructure diagram of the 3003 series aluminum alloy prepared in Comparative Example 1.

[0064] Reference signs: 310, manifold; 320, flow guide pipe; 330, adapter pipe; 340, fin; 341, connecting part; 342, heat dissipation part; 343, abutting groove; 301, medium flow channel; 1, indoor unit; 111, outdoor heat exchanger; 112, expansion valve; 2, outdoor unit; 101, compressor; 102, four-way valve; 103, outdoor heat exchanger; 104, expansion valve; 105, filter; 106, gas-liquid separator; 107, liquid side stop valve; 108, gas side stop valve. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solutions and advantages of the present application more clear, the following will further describe the present application in combination with the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not used to limit the present application.

[0066] The present inventors have found that active rare earth elements can form new intermetallic compounds with intermetallic compounds in aluminum alloys, for example, Al-Fe-RE, Al-Fe-Si-RE, etc. complex intermetallic compounds with Fe, Si, etc. Al-Fe, Al-Fe-Si are strong cathode intermetallic compounds for the aluminum alloy matrix, and thus are prone to local corrosion. The corrosion potential of Al-Fe-RE, Al-Fe-Si-RE, etc. intermetallic compounds containing rare earth elements is lower than that of Al-Fe, Al-Fe-Si, the potential difference between the intermetallic compounds and the aluminum alloy matrix is reduced, the local corrosion tendency is weakened, and the corrosion resistance of the aluminum alloy can be effectively improved. In the aluminum alloy containing manganese, the rare earth elements can form Al-Mn-RE and Al-Mn-Fe-RE complex intermetallic compounds, which can also shorten the potential difference between the intermetallic compounds and the aluminum alloy matrix. On the other hand, in addition to modifying the intermetallic compound phase, the corrosion potential of the aluminum matrix can also be improved by introducing alloying elements, which can shorten the difference between the corrosion potential of the intermetallic compounds and the aluminum alloy matrix and improve the corrosion resistance, for example, element Cu is a common alloying element that can strengthen the aluminum alloy. Studies have shown that when Cu exists in the form of solid solution in the aluminum alloy, the mechanical properties of the aluminum alloy can be improved, and the corrosion potential Ecorr of the aluminum alloy will also increase with the increase of the Cu content, and the pitting potential Epit will also increase, so that the aluminum alloy containing Cu is more resistant to pitting corrosion. However, it is worth noting that the introduction of excessive Cu will generate strong cathode phases in the aluminum alloy, which will sharply increase the corrosion tendency and reduce the corrosion resistance. Therefore, the effect of Cu on the corrosion resistance of the aluminum alloy depends on its distribution, content and existing form in the alloy.

[0067] Based on the above, the present inventors have realized uniform distribution of intermetallic compounds in the aluminum alloy by optimizing the selection of elements in the aluminum alloy, which can improve the corrosion potential of the aluminum matrix, reduce the corrosion potential of harmful intermetallic compounds, and reduce the difference between the corrosion potential of the aluminum alloy matrix and the intermetallic compounds, thereby reducing the tendency of local corrosion of harmful intermetallic compounds in the aluminum alloy material in the related art, and providing an aluminum alloy with excellent mechanical properties, good processing performance, good corrosion resistance, and the ability to deform.

[0068] The rare earth-containing aluminum alloy provided by the present application comprises the following components by mass fraction: Fe 0.05% to 0.30%, Si 0.05% to 0.25%, Mn 0.80% to 1.60%, Cu 0.05% to 0.45%, Ti 0.01% to 0.15%, Zr 0.10% to 0.20%, rare earth 0.05% to 0.30%, and the balance being Al and impurity elements, and the total mass percentage of the impurity elements is less than or equal to 0.20%.

[0069] Mn plays a very important role in regulating the microstructure and corrosion resistance. With the increase of Mn content, the strength of the aluminum alloy is enhanced, while the corrosion resistance remains unchanged. However, too high Mn content may have a negative impact on the casting performance of the aluminum alloy. For example, if the mass percentage of Mn exceeds 1.6%, brittle compound MnAl6 will be formed, which will reduce the plasticity of the aluminum alloy and cause cracking during cold deformation. In addition, since the corrosion potential of MnAl6 is close to that of the aluminum alloy matrix, the occurrence of micro-electric corrosion can be inhibited, thereby improving the overall corrosion resistance of the alloy. Therefore, by regulating the content of Mn element, the performance of the aluminum alloy can be optimized in different aspects. Considering the above factors, the content of Mn is selected to be in the range of 0.80% to 1.60%, and preferably in the range of 0.80% to 1.10%.

[0070] The microstructure and performance of the aluminum alloy are greatly related to the content and existing form of Fe. Fe can accelerate the precipitation of Mn in the solid solution of the aluminum alloy, greatly reduce the solubility of Mn in the aluminum alloy matrix, and make the aluminum alloy structure obtain finer grains during annealing. In the as-cast Al-Mn alloy, Fe is easy to enrich at the grain boundaries and form (FeMn)Al6 intermetallic compounds with Mn, which can accelerate the precipitation of Mn and further reduce the segregation of Mn in the aluminum alloy matrix, making the aluminum alloy structure uniform. The content of Fe in the aluminum alloy should not be too high. Excessive Fe will make the (FeMn)Al6 compound become coarse, and the coarse (FeMn)Al6 will reduce the mechanical properties of the aluminum alloy. At the same time, the Fe-containing intermetallic compound formed by excessive Fe is a strong cathode phase relative to the aluminum alloy matrix, which is easy to cause micro-electric corrosion and reduce the corrosion resistance of the alloy. Therefore, considering the above factors, the content of Fe should be strictly controlled below 0.3%, and preferably in the range of 0.05% to 0.30%.

[0071] Excessive Si in the aluminum alloy may cause Si to form Al-Fe-Si phase with Fe and Al. Al-Fe-Si phase usually has a positive corrosion potential, which is higher than that of the aluminum alloy matrix, which may cause severe corrosion of the alloy matrix, thereby reducing the corrosion resistance of the alloy. Therefore, during the addition and control of Si, a balance between mechanical properties and corrosion resistance needs to be achieved to ensure that the aluminum alloy can perform optimally in different application environments. Considering the above factors, the content of Si is selected to be in the range of 0.05% to 0.25%, and preferably in the range of 0.05% to 0.15%.

[0072] When Cu element is dissolved in the aluminum alloy matrix, the strength of the aluminum alloy can be effectively improved, and Cu can also promote the corrosion potential of the aluminum alloy matrix to become more positive. In the embodiments of the present application, the content of Cu is selected to be in the range of 0.15-0.45%, so that the proportion of Cu dissolved in the aluminum alloy is appropriate, and the prepared aluminum alloy has good strength and good corrosion resistance. When the mass percentage of Cu is less than 0.15%, the content of Cu is too low, and it is difficult to obtain the positive effect brought by the addition of Cu, for example, it is difficult to improve the corrosion resistance and the strength of the aluminum alloy. When the content of Cu is higher than 0.45%, the content of Cu is excessive, and the excessive Cu is easy to react with other alloy elements to generate cathodic phase intermetallic compounds to promote corrosion. Therefore, the content of Cu is controlled in the range of 0.15-0.45%. Preferably, the content of Cu is in the range of 0.15-0.35%.

[0073] Ti is a commonly used additive element in aluminum alloys, and has little effect on corrosion resistance. In the processing process, Ti is added in the form of Al-Ti intermediate alloy or Al-Ti-B intermediate alloy as a refiner. Ti forms TiAl3 phase with Al, becomes a non-spontaneous core during crystallization, and plays a role in refining the organization. In the embodiments of the present application, the content of Ti is in the range of 0.01%-0.15%.

[0074] At present, Zr is more and more added to aluminum alloys to improve the performance of the alloys. Zr is usually added as an additive in aluminum alloys. Zr has a refining effect on the grain of the aluminum alloy, and Zr is usually added in a trace amount to form fine second phase (i.e. intermetallic phase) particles in the aluminum alloy, reduce the deformation resistance, and improve the processing performance. By adding Zr in pure aluminum and aluminum alloys, the corrosion resistance can be improved by refining the grain and inhibiting recrystallization. Therefore, in the embodiments of the present application, the content of Zr is selected to be in the range of 0.10%-0.20%.

[0075] The addition of rare earth elements (RE) helps to refine the grains of the aluminum alloy, and by limiting the growth of the grains, a finer and more uniform grain structure can be formed, the strength and hardness of the alloy can be improved, and the local corrosion tendency can be reduced. At the same time, the addition of rare earth elements can form intermetallic compounds with other elements to inhibit corrosion, reduce the corrosion potential difference with the aluminum alloy matrix, and reduce galvanic corrosion. However, excessive addition of rare earth elements is easy to form a large amount of brittle Al-RE intermetallic compounds with the aluminum matrix, which destroys the mechanical properties of the material and worsens the corrosion resistance. Therefore, in the embodiments of the present application, the rare earth elements include at least one of La, Ce, Y, Nd, Sm, and Yb, and the content of the rare earth elements is in the range of 0.05%-0.30%, preferably in the range of 0.10%-0.30%, and more preferably in the range of 0.10%-0.25%.

[0076] In view of the above factors, preferably, the rare earth-containing aluminum alloy comprises the following components in mass fraction: Fe 0.05% to 0.20%, Si 0.05% to 0.15%, Mn 0.80% to 1.10%, Cu 0.15% to 0.35%, Ti 0.01% to 0.15%, Zr 0.10% to 0.20%, rare earth 0.10% to 0.25%, and the balance of Al and impurities, wherein the total mass fraction of the impurities is less than or equal to 0.20%.

[0077] The embodiment of the present application also provides a preparation method of the rare earth-containing aluminum alloy, which is used for preparing the rare earth-containing aluminum alloy as above. The preparation method of the rare earth-containing aluminum alloy comprises the following steps:

[0078] In step S100, a pure aluminum ingot, an aluminum-M intermediate alloy, an aluminum-rare earth intermediate alloy, a refining agent and a refining agent are provided as pre-prepared raw materials, M includes at least one of Fe, Si, Mn, Cu, Ti and Zr, and the mass fraction of each element in the pre-prepared raw materials is as follows: Fe 0.05% to 0.30%, Si 0.05% to 0.25%, Mn 0.80% to 1.6%, Cu 0.05% to 0.45%, Ti 0.01% to 0.15%, Zr 0.10% to 0.20%, rare earth 0.05% to 0.30%, and the balance of Al and impurities, wherein the total mass fraction of the impurities is less than or equal to 0.20%.

[0079] In step S200, the pure aluminum ingot is added to a smelting furnace to perform a first-stage hot melting treatment to obtain an aluminum melt.

[0080] In step S300, the aluminum-M intermediate alloy is added to the aluminum melt to perform a second-stage hot melting treatment to obtain an aluminum alloy melt.

[0081] In step S400, the aluminum-rare earth intermediate alloy is added to the aluminum alloy melt to perform a third-stage hot melting treatment to obtain a rare earth-containing aluminum alloy melt.

[0082] In step S500, the refining agent is added to the rare earth-containing aluminum alloy melt to perform a refining treatment to obtain a refined aluminum alloy melt.

[0083] In step S600, the refining agent is added to the refined aluminum alloy melt to perform a refining treatment to obtain a refined aluminum alloy melt.

[0084] In step S700, the refined aluminum alloy melt is sequentially subjected to casting, homogenization and extrusion treatment to obtain the rare earth-containing aluminum alloy.

[0085] The preparation method of the rare earth-containing aluminum alloy in the embodiments of the present application selects to add each component into the pure aluminum ingot by using the aluminum-M intermediate alloy and the aluminum-rare earth intermediate alloy, so that each component in the aluminum alloy can be dissolved more uniformly. In addition, the aluminum-M intermediate alloy is dissolved in the pure aluminum melt first, and then the aluminum-rare earth intermediate alloy is added, so that the rare earth elements can better reduce the non-metallic inclusions in the aluminum alloy, remove the gas, reduce the casting defects and refine the grains.

[0086] In some exemplary embodiments, the aluminum-M intermediate alloy includes at least one of an aluminum-manganese intermediate alloy, an aluminum-copper intermediate alloy, an aluminum-zirconium intermediate alloy, an aluminum-iron intermediate alloy, an aluminum-silicon intermediate alloy, and an aluminum-titanium intermediate alloy.

[0087] In some exemplary embodiments, the aluminum-rare earth intermediate alloy includes at least one of an aluminum-lanthanum intermediate alloy, an aluminum-cerium intermediate alloy, an aluminum-yttrium intermediate alloy, an aluminum-neodymium intermediate alloy, an aluminum-samarium intermediate alloy, and an aluminum-ytterbium intermediate alloy.

[0088] In some exemplary embodiments, before the first-stage heat melting treatment, the method further includes: preheating the pure aluminum ingot, the aluminum-M intermediate alloy, the aluminum-rare earth intermediate alloy, and the refiner, so as to reduce the temperature difference between the furnace charges when each intermediate alloy is gradually added subsequently, and improve the smelting efficiency. The preheating temperature is T0, and 180℃≤T0≤220℃, for example, T0 can be 180℃, 190℃, 200℃, 210℃, 220℃, or any range of the above two, and the preheating time is t0, 1h≤t0≤5h, for example, t0 can be 1h, 2h, 3h, 4h, 5h, or any range of the above two.

[0089] In some exemplary embodiments, in the first-stage heat melting treatment, the temperature of the aluminum melt obtained by heat melting the pure aluminum ingot is T1, and T1 satisfies: 720℃≤T1≤750℃, for example, T1 can be 720℃, 730℃, 740℃, 750℃, or any range of the above two.

[0090] In some exemplary embodiments, in the second-stage heat melting treatment, the aluminum-M intermediate alloy is added to the aluminum melt, and the temperature of the aluminum alloy melt obtained by heat melting is T2, and T2 satisfies: 720℃≤T2≤750℃, for example, T2 can be 720℃, 730℃, 740℃, 750℃, or any range of the above two.

[0091] In some exemplary embodiments, in the third stage of the hot melting process, an aluminum-rare earth intermediate alloy is added to the aluminum alloy melt, and the temperature of the obtained rare earth-containing aluminum alloy melt is T3, which satisfies: 700℃≤T3≤730℃, for example, T3 can be 700℃, 705℃, 710℃, 720℃, 730℃ or any range between any of the above.

[0092] wherein T1≤T2>T3, thus, in the second stage of the hot melting process, the aluminum-M intermediate alloy is hot melted at a higher temperature, and the aluminum-rare earth intermediate alloy is added at a higher temperature, so that the rare earth elements are more likely to react with other alloy elements to form stable intermetallic compounds, promoting the homogenization and alloying of the alloy. It helps to improve the uniformity and stability of the alloy.

[0093] After the third stage of the hot melting process, a refining process is performed, and in some exemplary embodiments, the refining agent includes at least one of KCl, NaCl, Na3AlF6, Na2SiF6, CaF2, C2Cl6, etc. The refining agent is mainly used to remove the mixed hydrogen element, plays a degassing role, reduces the porosity and porosity of the obtained rare earth-containing aluminum alloy; at the same time, it can remove non-metallic inclusions, and achieve the effect of purifying the aluminum alloy.

[0094] Specifically, the refining process includes: under the condition of T a , adding a refining agent to the rare earth-containing aluminum alloy melt, refining for a first time t m , and then standing for a second time t n , and obtaining the refined aluminum alloy melt after slagging; wherein 710℃≤T a ≤740℃, 0.1h≤t m ≤0.25h, and 0.15h≤t n ≤0.35h. The slagging during the refining process is to remove the non-metallic compounds formed in the melt during the standing process, effectively purifying the metal and improving the quality and purity of the metal.

[0095] After the refining process, a refining process is performed, and the refining agent includes at least one of aluminum-titanium-boron intermediate alloy, aluminum-titanium intermediate alloy, and aluminum-titanium-boron-rare earth intermediate alloy. The refining agent is used to limit the growth of crystal grains to form a fine and uniform grain structure, thereby improving the corrosion resistance of the aluminum alloy.

[0096] Specifically, the refining process includes: under the condition of T b , adding a refining agent to the refined aluminum alloy melt, stirring and mixing uniformly, refining for a third time t h , and obtaining the refined aluminum alloy melt after slagging; wherein 700℃≤T b ≤740℃, 0.15h≤t h≤0.5h. The slagging during the refining process refers to the removal of the block-shaped substance condensed on the surface of the liquid during the refining process.

[0097] The temperature of the aluminum alloy melt after the refining process is regulated to T c , and then a casting process is performed to cast an aluminum alloy rod, 700℃≤T c ≤720℃.

[0098] After the completion of the casting process, a homogenization process is performed on the aluminum alloy rod, and the temperature of the homogenization process is T j , 580℃≤T j ≤620℃, for example, T j may be 580℃, 590℃, 600℃, 610℃, 620℃, or any range of the above two. The holding time of the homogenization process is t j , 10h≤t j ≤14h, for example, t j may be 10h, 11h, 12h, 13h, 14h, or any range of the above two.

[0099] After the homogenization process, a water cooling process is performed, and the pre-cooled aluminum alloy short rod is obtained by cutting according to the preset size. The pre-cooled aluminum alloy short rod is heated to a temperature T e , and the holding time is t e , to obtain a pre-heated aluminum alloy short rod, 500℃≤T e ≤540℃, 1h≤t e ≤2h.

[0100] The pre-heated aluminum alloy short rod is subjected to an extrusion process, and the rare earth-containing aluminum alloy is obtained by rapidly cooling after the profile is extruded. Specifically, the die temperature of the extrusion process is T i , and the extrusion speed is V i , that is, the temperature of the pre-cooled aluminum alloy short rod is regulated to T i , and the pre-cooled aluminum alloy short rod is extruded at a speed V i to elongate the pre-cooled aluminum alloy short rod, and the profile is extruded according to an extrusion ratio of 400-500:1. Among them, T i satisfies: 460℃≤T i ≤510℃, for example, T i may be 460℃, 490℃, 500℃, 510℃, or any range of the above two; V i satisfies: 20m / min≤V i ≤25m / min, for example, V i may be 20m / min, 21m / min, 22m / min, 23m / min, 24m / min, 25m / min, or any range of the above two.

[0101] The embodiment of the present application also provides a heating and ventilation device, which comprises an aluminum alloy structure, the aluminum alloy structure comprises at least one of an aluminum alloy heat exchange component and an aluminum alloy pipe, and the material of the aluminum alloy structure is the rare earth-containing aluminum alloy as described above. By applying the rare earth-containing aluminum alloy of the present application to the heating and ventilation device, the rare earth-containing aluminum alloy can have good corrosion resistance when being in contact with a heat exchange medium inside the heating and ventilation device or being in a humid environment, thereby effectively improving the use stability of the heating and ventilation device.

[0102] In some exemplary embodiments, the tensile strength of the aluminum alloy structure is A, and A satisfies 90MPa≤A≤108Mpa, for example, A can be 90Mpa, 95Mpa, 98Mpa, 100Mpa, 105Mpa or any range of the above two. By selecting the tensile strength in the range of 90MPa≤A≤108Mpa, the aluminum alloy structure has good plasticity, and it is convenient to process the aluminum alloy structure with the required shape according to the use requirements of the heating and ventilation device.

[0103] In some exemplary embodiments, the yield strength of the aluminum alloy structure is B, and B satisfies 35MPa≤B≤50Mpa, for example, B can be 35Mpa, 38Mpa, 42Mpa, 45Mpa, 50Mpa or any range of the above two. By selecting the yield strength in the range of 35MPa≤B≤50Mpa, the aluminum alloy structure has good structural strength and is not easy to deform, so that the aluminum alloy structure can be stably connected with other structural parts of the heating and ventilation device.

[0104] In some exemplary embodiments, the elongation of the aluminum alloy structure is C, and C satisfies 45%≤C≤55%, for example, C can be 45%, 48%, 50%, 53%, 55% or any range of the above two. By selecting the elongation in the range of 45%≤C≤55%, the aluminum alloy structure can resist various stresses within a certain range and is not easy to break, so that the aluminum alloy structure can be applied to an environment with frequent heat exchange.

[0105] The heating and ventilation device of the embodiment of the present application comprises a plurality of functional devices, the plurality of functional devices comprises a heat exchanger, and the heat exchanger comprises at least one aluminum alloy heat exchange component, and the aluminum alloy heat exchange component has a heat exchange channel for the flow of a heat exchange medium.

[0106] As shown in FIG. 1, the pipe structure of the heat exchanger comprises a plurality of flow guide pipes 320 for transmitting the heat exchange medium, and the plurality of flow guide pipes 320 are arranged side by side. The heat exchanger further comprises a plurality of fins 340, as shown in FIG. 1, in some embodiments, the plurality of fins 340 are arranged in a direction perpendicular to the direction in which the plurality of flow guide pipes 320 are arranged side by side, each flow guide pipe 320 penetrates and is connected to the plurality of fins 340, and the plurality of fins 340 increase the heat exchange area to increase the heat exchange efficiency of the heat exchanger. Optionally, at least one of the fins 340 and the flow guide pipes 320 is an aluminum alloy heat exchange member, that is, the material of the fins 340 is selected from the aluminum alloy containing rare earth as described above.

[0107] As shown in FIG. 1, in some embodiments, the pipe structure of the heat exchanger further comprises a plurality of collecting pipes 310 and a plurality of adapter pipes 330, the number of the plurality of collecting pipes 310 is at least one, the internal passages of each of the plurality of collecting pipes 310 are in communication with the internal passages of the plurality of flow guide pipes 320 to collect and distribute the heat exchange medium, the number of the plurality of adapter pipes 330 is at least one, the internal passages of each of the plurality of collecting pipes 310 are in communication with the internal passages of the at least one of the plurality of adapter pipes 330, so that the heat exchange medium can enter and exit the plurality of collecting pipes 310 through the plurality of adapter pipes 330. Among them, at least one of the plurality of collecting pipes 310, the plurality of flow guide pipes 320 and the at least one of the plurality of adapter pipes 330 is an aluminum alloy heat exchange member, that is, the material is selected from the aluminum alloy containing rare earth as described above.

[0108] In some exemplary embodiments, the plurality of collecting pipes 310, the plurality of flow guide pipes 320 and the plurality of adapter pipes 330 can be independently selected from heat exchange round pipes and heat exchange flat pipes, that is, all of the plurality of collecting pipes 310, the plurality of flow guide pipes 320 and the plurality of adapter pipes 330 can be heat exchange round pipes, or all of them can be heat exchange flat pipes, or a part of them are heat exchange round pipes and the other part are heat exchange flat pipes, and when at least one of the plurality of collecting pipes 310, the plurality of flow guide pipes 320 and the plurality of adapter pipes 330 is an aluminum alloy heat exchange member, the pipe can be a heat exchange round pipe or a heat exchange flat pipe, and when a plurality of the plurality of collecting pipes 310, the plurality of flow guide pipes 320 and the plurality of adapter pipes 330 are aluminum alloy heat exchange members, the plurality of pipes can all be heat exchange round pipes or all be heat exchange flat pipes, or a part of them are heat exchange round pipes and the other part are heat exchange flat pipes.

[0109] In the embodiments of the present application, the heat exchange round pipe is a pipe with a circular cross section, and the heat exchange flat pipe is a pipe with an elliptical, rectangular or other cross section with different length and width. Optionally, the heat exchange round pipe can be provided with a medium flow channel 301 for the flow of heat exchange medium, and the heat exchange flat pipe can be provided with at least one medium flow channel 301 for the flow of heat exchange medium. When the heat exchange flat pipe has a plurality of medium flow channels 301, the plurality of medium flow channels 301 can be arranged side by side in a straight line direction.

[0110] Exemplarily, as shown in FIG. 1, the heat exchanger includes two header pipes 310, a plurality of flow guide pipes 320 and a plurality of adapter pipes 330. The plurality of flow guide pipes 320 are arranged side by side in a first direction, the two header pipes 310 are arranged on opposite sides of the plurality of flow guide pipes 320 in a second direction perpendicular to the first direction, and each header pipe 310 is connected to the end of all flow guide pipes 320. The plurality of adapter pipes 330 are connected to one of the header pipes 310. Among them, the two header pipes 310 and the plurality of adapter pipes 330 are heat exchange round pipes, the plurality of flow guide pipes 320 are heat exchange flat pipes, and at least one of the two header pipes 310, the plurality of flow guide pipes 320 and the plurality of adapter pipes 330 is an aluminum alloy heat exchange member. As shown in FIG. 2, when the plurality of flow guide pipes 320 are heat exchange flat pipes, the plurality of flow guide pipes 320 and the same fin 340 are transversely sectioned. As shown in FIG. 2, the heat exchange flat pipe includes a plurality of medium flow channels 301 arranged side by side in a straight line direction, the plurality of fins 340 are arranged side by side in a direction, the heat exchange flat pipe is arranged in a slot on the fin 340 in a transmission direction, and the plurality of medium flow channels 301 are arranged side by side in a direction. The two are perpendicular to each other. The use of heat exchange flat pipes can make full use of space for the flow of heat exchange medium, increase the specific surface area of heat exchange, and improve the heat dissipation efficiency.

[0111] In some embodiments, as shown in FIG. 3, the pipe structure of the heat exchanger can not include the header pipe 310, but at least one flow guide pipe 320 and at least one adapter pipe 330. The end of the flow guide pipe 320 is connected to one end of the adapter pipe 330, and the other end of the adapter pipe 330 is connected to an external pipe to allow the heat exchange medium transmitted by the external pipe to enter and exit the flow guide pipe 320. Among them, the heat exchanger can further include a plurality of fins 340, the fin 340 has a plurality of mounting openings for the flow guide pipe 320 to pass through, and the flow guide pipe 320 is connected to the fin 340.

[0112] Exemplarily, as shown in FIG. 3, the pipe structure of the heat exchanger comprises a plurality of flow guide pipes 320 and a plurality of adapter pipes 330. The plurality of flow guide pipes 320 respectively transmit a plurality of fins 340, and the end portions of the plurality of flow guide pipes 320 protrude towards the same side of the plurality of fins 340 in the direction in which the plurality of fins 340 are arranged side by side, and are connected to the plurality of adapter pipes 330 one by one. At least one of the flow guide pipe 320, the adapter pipe 330 and the fin 340 is an aluminum alloy heat exchange member. As shown in FIG. 4, when the flow guide pipe 320 is a heat exchange round pipe, a plurality of flow guide pipes 320 are arranged in the transverse section of the same fin 340.

[0113] In some embodiments, the plurality of fins 340 are arranged side by side along the axial direction of the flow guide pipe 320. The fin comprises a connecting portion 341 and a heat dissipation portion 342. The connecting portion 341 is sleeved on the outside of the flow guide pipe 320. The heat dissipation portion 342 of the same fin 340 is integrally arranged with the connecting portion 341. The heat dissipation portion 342 extends in a plane perpendicular to the axial direction of the flow guide pipe 320, thereby increasing the heat exchange area and improving the heat exchange efficiency. The connecting portion 341 extends along the axial direction of the flow guide pipe 320, for example, the connecting portion 341 extends on one side or both sides of the axial direction of the flow guide pipe 320. The connecting portion 341 increases the contact area between the fin 340 and the flow guide pipe 320, thereby improving the heat exchange efficiency. Further, the connecting portion 341 of the fin 340 is in contact with the adjacent fin 340, so as to increase the coverage area of the fin 340 in the axial direction of the flow guide pipe 320, thereby further increasing the contact area between the plurality of fins 340 and the flow guide pipe 320.

[0114] Optionally, as shown in FIG. 5, which is a longitudinal sectional view of the connection between the flow guide pipe 320 and the fin 340 according to an embodiment of the present application, the connecting portion 341 of the fin 340 extends on one side of the axial direction of the flow guide pipe 320 and is in contact with the heat dissipation portion 342 of the adjacent fin 340.

[0115] Optionally, as shown in FIG. 6, which is a longitudinal sectional view of the connection between the flow guide pipe 320 and the fin 340 according to another embodiment of the present application, a butt joint groove 343 is formed at the connection between the connecting portion 341 and the heat dissipation portion 342 of the fin 340. The connecting portion 341 of the fin 340 extends on one side of the axial direction of the flow guide pipe 320 and extends into the butt joint groove 343 of the adjacent fin 340 to be in contact with at least one of the heat dissipation portion 342 and the heat dissipation portion 342.

[0116] The heating and ventilation device further comprises at least one connecting pipe. The two functional devices are connected through the at least one connecting pipe. For example, the two functional devices are connected through one connecting pipe, or the two functional devices are connected through a plurality of connecting pipes. At least one of the connecting pipes is an aluminum alloy pipe, and at least two of the functional devices are connected through the aluminum alloy pipe.

[0117] In some exemplary embodiments, the heating and ventilation device can be an air conditioning device, the air conditioning device comprising an outdoor unit, an indoor unit, and a plurality of adapter pipes connecting the outdoor unit and the indoor unit, the plurality of functional components of the heating and ventilation device comprising the plurality of functional components of the outdoor unit and the plurality of functional components of the indoor unit, wherein the outdoor unit further comprises a plurality of outdoor unit pipes connecting the plurality of functional components inside the outdoor unit, and the indoor unit comprises a plurality of indoor unit pipes connecting the plurality of functional components inside the indoor unit. In this case, the connecting pipes connecting the plurality of functional components comprise the plurality of indoor unit pipes, the plurality of outdoor unit pipes, and the plurality of adapter pipes, and at least one of the pipes is an aluminum alloy pipe.

[0118] The present application does not limit the connection mode of the plurality of functional components and the plurality of indoor unit pipes of the indoor unit, and the connection mode of the plurality of functional components and the plurality of outdoor unit pipes of the outdoor unit, and the specific selection can be made according to actual needs.

[0119] Exemplarily, as shown in FIG. 7, the plurality of functional components of the indoor unit 1 comprise an outdoor heat exchanger 111 and an expansion valve 112, and the plurality of functional components of the indoor unit 1 are connected by at least one indoor unit pipe. As shown in FIG. 7, the plurality of functional components of the outdoor unit 2 comprise a compressor 101, a four-way valve 102, an outdoor heat exchanger 103, an expansion valve 104, a filter 105, a gas-liquid separator 106, a liquid-side stop valve 107, and a gas-side stop valve 108, and the plurality of functional components of the outdoor unit 2 are connected by a plurality of outdoor unit pipes. In FIG. 7, the liquid-side stop valve 107 is connected to the expansion valve 112 by an adapter pipe, and the expansion valve 112 is connected to the outdoor heat exchanger 111 by an adapter pipe. The direction indicated by the arrow in FIG. 7 is a schematic diagram of the flow direction of the heat exchange medium in the indoor unit 1 and the outdoor unit 2. At least one of the indoor unit pipe, the outdoor unit pipe, and the adapter pipe is an aluminum alloy pipe, and at least one of the outdoor heat exchanger 103 and the indoor heat exchanger 112 can be a heat exchanger comprising an aluminum alloy heat exchange component as described above.

[0120] The preparation method of the aluminum alloy is introduced below in combination with the embodiments and comparative examples. Those skilled in the art will understand that the preparation method described in the present application is only an example, and any other suitable preparation method is within the scope of the present application.

[0121] In the embodiments and comparative examples of the present application, the performance test method of the aluminum alloy is as follows:

[0122] (1) Tensile strength test method

[0123] Reference: GB / T 228.1-2010.

[0124] (2) Yield strength test method

[0125] Reference: GB / T 228.1-2010.

[0126] (3) Elongation test method

[0127] Reference national standard: GB / T 228.1-2010.

[0128] (4) Corrosion resistance test method

[0129] The corrosion depth of the aluminum alloy was measured after 12 days of exposure to ASTM G85 standard cyclic acidic seawater test (SWAAT).

[0130] Example 1

[0131] Step S111: Provide pre-formulated raw materials including pure aluminum ingots (purity 99.75%), aluminum-M master alloys (including aluminum-manganese master alloys, aluminum-copper master alloys, and aluminum-zirconium master alloys), aluminum-rare earth master alloys (including aluminum-cerium master alloys and aluminum-lanthanum master alloys), refining agents (including aluminum-titanium-boron master alloys), and refining agents. Preheat the materials except for the refining agents to a temperature T0 of 200°C for a preheating time t0 of 2 hours. Provide refining agents (including hexachloroethane) for later use.

[0132] The mass percentages of each element in the pre-prepared raw materials in 100 parts by mass of all the above-mentioned pre-prepared raw materials are as follows: Fe 0.2%; Si 0.15%; Cu 0.15%; Mn 0.92%; Ti 0.025%; Zr 0.1%; rare earth 0.1%; balance Al.

[0133] Step S112: Add pure aluminum ingots to the smelting furnace for the first stage of hot melting treatment to obtain aluminum melt. The temperature T1 of the aluminum melt is 740℃~750℃.

[0134] Step S113: Add aluminum-M master alloy (including aluminum-manganese master alloy, aluminum-copper master alloy and aluminum-zirconium master alloy) to the aluminum melt, stir and mix evenly, and carry out the second stage hot melt treatment to obtain aluminum alloy melt. The temperature T2 of the aluminum alloy melt is 720℃~730℃.

[0135] Step S114: Add aluminum-rare earth master alloy (including aluminum-cerium master alloy and aluminum-lanthanum master alloy) to the aluminum alloy melt, and after the third stage of hot melting treatment, obtain a rare earth aluminum alloy melt. The temperature T3 of the rare earth aluminum alloy melt is 710℃~730℃.

[0136] Step S115, in T a Under specific temperature conditions, a refining agent is added to the rare earth-containing aluminum alloy melt for refining treatment. The refining time is t. m And let it stand for a second time t n Afterwards, the refined aluminum alloy melt was obtained by removing the slag.a = 720℃, t m = 0.15h, t n = 0.25h.

[0137] Step S116, regulating the temperature of the refined aluminum alloy melt to T b = 720℃, t h = 0.25h. b = 720℃, t h = 0.25h.

[0138] Step S117, regulating the temperature of the refined aluminum alloy melt to T c = 710℃. c = 710℃.

[0139] Step S118, after the casting treatment, homogenizing the aluminum alloy rod, the homogenizing temperature T j = 580℃, t j = 10h. After the homogenizing treatment, water cooling treatment is performed, and the pre-cooled aluminum alloy short rod is obtained by cutting according to the preset size.

[0140] Step S119, heating the pre-cooled aluminum alloy short rod to a temperature T e = 510℃, t e = 1h. e = 510℃, t e = 1h.

[0141] Step S120, using a horizontal extruder to perform hot extrusion treatment on the pre-heated aluminum alloy short rod, the die temperature T i = 500℃, the extrusion speed V i = 20m / min, the extrusion ratio is 400:1, and the profile is obtained after rapid cooling.

[0142] The rare earth-containing aluminum alloy obtained in this embodiment has a tensile strength A of 95Mpa, a yield strength B of 38Mpa, and an elongation C of 52% at room temperature (25℃), and a corrosion depth h of 150μm after 12 days of exposure in the cyclic acidic seawater test (SWAAT) under the ASTM G85 standard.

[0143] Example 2

[0144] Step S121, providing pre-prepared raw materials including pure aluminum ingot (purity 99.75), aluminum-M intermediate alloy (including aluminum-manganese intermediate alloy, aluminum-copper intermediate alloy, aluminum-zirconium intermediate alloy), aluminum-rare earth intermediate alloy (including aluminum-lanthanum-cerium mixed rare earth intermediate alloy), refiner (including aluminum-titanium-boron intermediate alloy) and refining agent, and preheating the above materials except the refining agent, the preheating temperature T0 is 200℃, and the preheating time t0 is 2h. And provide the refining agent (including hexachloroethane) for standby.

[0145] Wherein, the mass ratio of each element in the pre-prepared raw materials in the above all pre-prepared raw materials based on 100 parts by mass is as follows: Fe 0.2%; Si 0.15%; Cu 0.25%; Mn 0.92%; Ti 0.025%; Zr 0.1%, rare earth 0.1%; the balance is Al.

[0146] Step S122, adding pure aluminum ingot into the smelting furnace, carrying out first stage hot melting treatment, obtaining aluminum melt, the temperature T1 of the aluminum melt is 740℃-750℃.

[0147] Step S123, adding aluminum-M intermediate alloy (including aluminum-manganese intermediate alloy, aluminum-copper intermediate alloy and aluminum-zirconium intermediate alloy) into the aluminum melt, stirring and mixing uniformly, carrying out second stage hot melting treatment, obtaining aluminum alloy melt, the temperature T2 of the aluminum alloy melt is 720℃-730℃.

[0148] Step S124, adding aluminum-rare earth intermediate alloy (including aluminum-lanthanum-cerium mixed rare earth intermediate alloy) into the aluminum alloy melt, after third stage hot melting treatment, obtaining rare earth-containing aluminum alloy melt, the temperature T3 of the rare earth-containing aluminum alloy melt is 710℃-730℃.

[0149] Step S125, under the temperature condition of T a , adding refining agent into the rare earth-containing aluminum alloy melt, carrying out refining treatment, the first refining time t m , and after standing for the second time t n , obtaining refined aluminum alloy melt, T a =720℃, t m =0.15h, t n =0.25h.

[0150] Step S126, under the temperature condition of T b , adding refiner (aluminum-titanium-boron intermediate alloy) into the refined aluminum alloy melt, carrying out refining treatment, the third refining time t h , and after skimming, obtaining refined aluminum alloy melt, T b =720℃, t h =0.25h.

[0151] Step S127, the temperature of the refined aluminum alloy melt is regulated to T c and then casting treatment is performed to cast an aluminum alloy rod, T c = 710℃.

[0152] Step S128, after the completion of the casting treatment, homogenization treatment is performed on the aluminum alloy rod, the temperature T j of the homogenization treatment is 600℃, and the homogenization holding time t j is 10h. After the homogenization treatment, water cooling treatment is performed, and the pre-cooled aluminum alloy short rod is obtained by cutting according to the preset size.

[0153] Step S129, the pre-cooled aluminum alloy short rod is subjected to heating treatment, heated to a temperature T e and held for a time t e , to obtain a pre-heated aluminum alloy short rod, T e = 530℃, and t e = 1h.

[0154] Step S130, a horizontal extruder is used to perform hot extrusion treatment on the pre-heated aluminum alloy short rod, the die temperature T i of the extrusion treatment is 500℃, the extrusion speed V i is 20m / min, and the extrusion ratio is 400:1. After the profile is extruded, it is rapidly cooled to obtain the rare earth-containing aluminum alloy.

[0155] The rare earth-containing aluminum alloy obtained in this embodiment has a tensile strength A of 98Mpa, a yield strength B of 41Mpa, and an elongation C of 50% at room temperature (25℃). After being exposed to the cyclic acidic seawater test (SWAAT) under the ASTM G85 standard for 12 days, the corrosion depth h is 120μm.

[0156] In each of the following examples and comparative examples, the main difference in the preparation method of the rare earth-containing aluminum alloy lies in the difference in the parameters of the aluminum alloy raw material, homogenization treatment, and heating treatment.

[0157] Specifically, the difference between Example 3-Example 5 and Example 1 lies in the difference in the composition of the pre-prepared raw material, as well as the difference in the parameters of the homogenization treatment and heating treatment.

[0158] The difference between Comparative Example 1 and Example 1 lies in that Comparative Example 1 directly uses an aluminum rod of the 3003 series (the specific composition is referred to the national standard: GB / T 3190-2020) for homogenization treatment, and the process sequence in the homogenization treatment and subsequent treatment steps is the same, but the process parameters are different.

[0159] The related preparation parameters of the aluminum alloy of Example 1 to Example 5 and Comparative Example 1, as well as the properties of the corresponding rare earth-containing aluminum alloy, are shown in Table 1.

[0160] Table 1

[0161] According to the results in Table 1, it can be seen that, by adding rare earth elements and adjusting the proportions of the components of the rare earth-containing aluminum alloy within a suitable range, the mechanical properties of the processed rare earth-containing aluminum alloy are good, and the tensile strength, yield strength and elongation can all meet the performance requirements of the 3003 type aluminum alloy in the prior art. Moreover, in the cyclic acid seawater test, the corrosion depth of the rare earth-containing aluminum alloy prepared in the present application is much smaller than that of the 3003 type aluminum alloy, and the rare earth-containing aluminum alloy prepared in the present application has good corrosion resistance.

[0162] The present application also uses a scanning electron microscope to detect the microstructure of the aluminum alloy. Figure 8 shows the microstructure of the rare earth-containing aluminum alloy prepared in Example 3, and Figure 9 shows the microstructure of the 3003 type aluminum alloy prepared in Comparative Example 1. The light-colored area indicated by the arrow s in Figures 8 and 9 is the position of the intermetallic compound (second phase) distributed between the aluminum alloy. According to Figures 8 and 9, it can be seen that the intermetallic compound of the 3003 type aluminum alloy prepared in Comparative Example 1 is in the form of a long strip, and the uniformity of distribution is poor. The intermetallic compound of the rare earth-containing aluminum alloy prepared in Example 3 is in the form of particles, and the size is small and uniformly distributed. Therefore, the rare earth-containing aluminum alloy prepared in Example 3 has good corrosion resistance.

[0163] It should be noted that the present application is not limited to the above-described embodiments. The above-described embodiments are only examples, and embodiments having the same technical idea and playing the same role and effect as the technical solution of the present application are all included in the technical scope of the present application. In addition, within the scope of the main idea of the present application, various modifications that can be thought of by those skilled in the art, and other ways constructed by combining part of the components of the embodiments are also included in the scope of the present application.

Claims

1. A rare earth containing aluminum alloy, wherein, comprises the following components in the following mass fractions: Fe 0.05% to 0.30%, Si 0.05% to 0.25%, Mn 0.80% to 1.6%, Cu 0.05% to 0.45%, Ti 0.01% to 0.15%, Zr 0.10% to 0.20%, rare earth 0.05% to 0.30%, the balance being Al and impurity elements, the total mass percentage of the impurity elements being less than or equal to 0.20%.

2. The rare earth-containing aluminum alloy of claim 1, wherein, The mass percentage of Cu ranges from 0.10% to 0.35% based on the mass of the rare earth-containing aluminum alloy.

3. The rare earth-containing aluminum alloy according to claim 1, wherein the rare earth comprises at least one of La, Ce, Y, Nd, Sm, and Yb; the total mass percentage of each element of the rare earth ranges from 0.10% to 0.25% based on the mass of the rare earth-containing aluminum alloy.

4. The rare earth-containing aluminum alloy of claim 1, wherein, The rare earth-containing aluminum alloy comprises the following components in the following mass fractions: Fe 0.05% to 0.20%, Si 0.05% to 0.15%, Mn 0.80% to 1.10%, Cu 0.15% to 0.35%, Ti 0.01% to 0.15%, Zr 0.10% to 0.20%, rare earth 0.10% to 0.25%, the balance being Al and impurity elements, the total mass percentage of the impurity elements being less than or equal to 0.20%.

5. A method of producing a rare earth-containing aluminum alloy, wherein, comprises: providing pre-prepared raw materials of pure aluminum ingot, aluminum-M intermediate alloy, aluminum-rare earth intermediate alloy, refining agent, and refining agent, M comprising at least one of Fe, Si, Mn, Cu, Ti, and Zr, and making the mass percentage of each element in the pre-prepared raw materials be as follows based on 100 mass parts of all the pre-prepared raw materials: Fe 0.05% to 0.30%, Si 0.05% to 0.25%, Mn 0.80% to 1.6%, Cu 0.05% to 0.45%, Ti 0.01% to 0.15%, Zr 0.10% to 0.20%, rare earth 0.05% to 0.30%, the balance being Al and impurity elements, the total mass percentage of the impurity elements being less than or equal to 0.20%; adding the pure aluminum ingot into a smelting furnace to perform a first-stage hot melting treatment to obtain an aluminum melt; adding the aluminum-M intermediate alloy into the aluminum melt to perform a second-stage hot melting treatment to obtain an aluminum alloy melt; adding the aluminum-rare earth intermediate alloy into the aluminum alloy melt to perform a third-stage hot melting treatment to obtain a rare earth-containing aluminum alloy melt; adding the refining agent into the rare earth-containing aluminum alloy melt to perform a refining treatment to obtain a refined aluminum alloy melt; adding the refining agent into the refined aluminum alloy melt to perform a refining treatment to obtain a refined aluminum alloy melt; adding the refining agent into the refined aluminum alloy melt to perform a refining treatment to obtain a refined aluminum alloy melt; casting, homogenizing, and extruding the aluminum alloy melt in sequence to obtain the rare earth-containing aluminum alloy.

6. The preparation method of the rare earth-containing aluminum alloy according to claim 5, wherein the aluminum-M intermediate alloy comprises at least one of aluminum-manganese intermediate alloy, aluminum-copper intermediate alloy, aluminum-zirconium intermediate alloy, aluminum-iron intermediate alloy, aluminum-silicon intermediate alloy, and aluminum-titanium intermediate alloy; The aluminum-rare earth intermediate alloy includes at least one of aluminum-lanthanum intermediate alloy, aluminum-cerium intermediate alloy, aluminum-yttrium intermediate alloy, aluminum-neodymium intermediate alloy, aluminum-samarium intermediate alloy, and aluminum-ytterbium intermediate alloy. The refiner includes at least one of aluminum-titanium-boron intermediate alloy, aluminum-titanium intermediate alloy, and aluminum-titanium-boron-rare earth intermediate alloy. The refining agent includes at least one of KCl, NaCl, Na3AlF6, Na2SiF6, CaF2, and C2Cl6.

7. The method of producing a rare earth-containing aluminum alloy according to claim 5, wherein The first-stage hot melting treatment further includes: The pure aluminum ingot, the aluminum-M intermediate alloy, the aluminum-rare earth intermediate alloy, and the refiner are subjected to preheating treatment, the preheating treatment has a temperature T0 and a time t0, wherein 180℃≤T0≤220℃ and 1h≤t0≤5h.

8. The method for preparing the rare earth-containing aluminum alloy according to claim 5, wherein the temperature T1 of the aluminum melt satisfies 720℃≤T1≤750℃. The temperature T2 of the aluminum alloy melt satisfies 720℃≤T2≤750℃. The temperature T3 of the rare earth-containing aluminum alloy melt satisfies 700℃≤T3≤730℃.

9. The method for preparing the rare earth-containing aluminum alloy according to claim 5, wherein the temperature T1 of the aluminum melt satisfies 720℃≤T1≤750℃.

10. The method for preparing the rare earth-containing aluminum alloy according to claim 5, wherein the temperature T2 of the aluminum alloy melt satisfies 720℃≤T2≤750℃. The refining treatment comprises: adding the refining agent into the rare earth-containing aluminum alloy melt at T a under temperature conditions, refining for a first time t m , and standing for a second time t n , to obtain the refined aluminum alloy melt after skimming; wherein 710℃≤T a ≤740℃, 0.1h≤t m ≤0.25h, 0.15h≤t n ≤0.35h. The refining process comprises: adding a refining agent into the aluminum alloy melt at T b temperature conditions, refining for a third time t h , and obtaining the aluminum alloy melt after slagging; wherein 700℃≤T b ≤740℃, 0.15h≤t h ≤0.5h. The heating and cooling equipment includes an aluminum alloy structure, the aluminum alloy structure includes at least one of an aluminum alloy heat exchange component and an aluminum alloy pipe, and the material of the aluminum alloy structure is selected from the rare earth-containing aluminum alloy according to any one of claims 1-4. The temperature of the homogenization is T j and the time is t j , where 580°C ≤ T j ≤ 620°C, 10h ≤ t j ≤ 14h. The die temperature of the extrusion process is T i , and the extrusion speed is V i , wherein 460℃≤T i ≤510℃, and 20m / min≤V i ≤25m / min.

11. A heating and ventilating apparatus wherein, The heating and cooling equipment satisfies at least one of the following conditions:

12. The heating and ventilation apparatus of claim 11, wherein, (1) the tensile strength A of the aluminum alloy structure satisfies 90MPa≤A≤108Mpa; (2) the yield strength B of the aluminum alloy structure satisfies 35MPa≤B≤50Mpa; (3) the elongation rate C of the aluminum alloy structure satisfies 45%≤C≤55%. The heating and cooling equipment includes a plurality of functional components, the plurality of functional components includes a heat exchanger, the heat exchanger includes at least one of the aluminum alloy heat exchange component, and the aluminum alloy heat exchange component has a heat exchange channel inside for the flow of heat exchange medium.

13. The heating and ventilation apparatus of claim 11, wherein, The heat exchanger includes:

14. The heating and ventilation apparatus of claim 13, wherein, a plurality of flow guide pipes for transmitting heat exchange medium; and a plurality of fins, the plurality of fins are arranged in a direction perpendicular to the direction in which the plurality of flow guide pipes are arranged, and each of the flow guide pipes penetrates and connects to the plurality of fins; wherein at least one of the fins and the flow guide pipes is the aluminum alloy heat exchange component. The heat exchanger further includes at least one adapter pipe; 15. The heating appliance of claim 14, wherein, one end of the adapter pipe is directly connected to the flow guide pipe, and the other end is connected to an external pipeline; or the heat exchanger further includes at least one manifold, the internal passage of each of the manifolds is in communication with the internal passages of the plurality of flow guide pipes to collect and distribute the heat exchange medium, and the internal passage of each of the manifolds is also in communication with the internal passage of at least one of the adapter pipes to allow the heat exchange medium to enter and exit the manifold through the adapter pipe. ​ At least one of the at least one manifold and the at least one adapter pipe is made of the aluminum alloy heat exchange component.

16. The heating and ventilation apparatus of claim 14, wherein, The fin comprises a connecting portion and a radiating portion, the connecting portion is sleeved on the outer portion of the flow guide pipe, and the connecting portion extends along the axial direction of the flow guide pipe.

17. The heating and ventilation device according to claim 16, wherein, the connecting portion of the fin extends along one side of the axial direction of the flow guide pipe and is in contact with the radiating portion of the adjacent fin; or the connecting portion of the fin is in contact with at least one of the radiating portion and the radiating portion of the adjacent fin.

18. The heating and ventilation device according to claim 13, wherein, at least part of the aluminum alloy heat exchange component is a heat exchange round pipe; and / or at least part of the aluminum alloy heat exchange component is a heat exchange flat pipe.

19. The heating and ventilation device according to claim 18, wherein, the heat exchange round pipe is internally provided with a medium flow channel for the flow of heat exchange medium; the heat exchange flat pipe is internally provided with at least one medium flow channel for the flow of heat exchange medium.

20. The heating and ventilation apparatus of claim 11, wherein, The heating and ventilation device comprises a plurality of functional devices and at least one aluminum alloy pipe, and at least two of the functional devices are connected through the aluminum alloy pipe.

21. The heating and ventilation apparatus of claim 20, wherein, The heating and ventilation device comprises an indoor unit, an outdoor unit, and a plurality of connecting pipes connecting the indoor unit and the outdoor unit; The indoor unit comprises a part of the functional devices and a plurality of indoor pipes connecting the functional devices; The outdoor unit comprises another part of the functional devices and a plurality of outdoor pipes connecting the functional devices; At least one of the plurality of connecting pipes, the plurality of indoor pipes, and the plurality of outdoor pipes is the aluminum alloy pipe.

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