Aluminum matrix composite heat sink pipe material with controllable layer corrosion and preparation process

Abstract

This invention discloses an aluminum-based composite radiator tube material with controllable layered corrosion and its preparation process, relating to the field of aluminum alloy composite material technology. The tube material is a three-layer composite structure consisting of 4045 sheath material, modified 3Z23 core material, and 4045 sheath material. The core material is one of 3Z23, 3Z23E, 3Z23M, and 3Z23ME, and is controlled by a narrow range of composition using non-recycled waste materials, satisfying Fe+Si≤0.35% and Fe+Mn≤1.75%. The Cu content of 3Z23E and 3Z23ME is 0.60~0.70%. This invention employs a core material casting process that combines "no recycled waste with narrow-range composition control," strictly controlling Fe+Si ≤ 0.35% and Fe+Mn ≤ 1.75%. This significantly reduces the formation of harmful phases such as AlMnFeSi, fundamentally eliminating pitting corrosion initiation sources. As a result, the pipe exhibits a pure lamellar corrosion morphology in the SWAAT corrosion test, with a corrosion depth ≤ 50% of the wall thickness after 21 days. This solves the problem of non-lamellar corrosion and localized pitting failure caused by large fluctuations in impurities in conventional pipe materials.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy composite materials technology, specifically to an aluminum-based composite radiator tube with controllable layered corrosion and its preparation process. Background Technology

[0002] Aluminum-based composite radiator tubing is a brazed aluminum alloy composite tubing with an aluminum alloy base and a multi-layer composite structure design. It is specifically designed for use as the core of heat exchangers in automobiles, HVAC, and industrial refrigeration. It typically consists of a three-layer structure: a sheath, a core, and a sheath. It is the core functional material for achieving lightweight, high thermal conductivity, brazing capability, and corrosion resistance in radiators. With the rapid development of automotive lightweighting, new energy thermal management, and high-efficiency HVAC industries, radiators are being upgraded towards ultra-thinness, high reliability, long lifespan, and resistance to severe corrosion.

[0003] Currently, the commonly used aluminum-based composite heat sink tubes in the industry are mostly three-layer composite structures of 4045 / 3Z23 / 4045 and 4045 / 3Z23M / 4045. In actual customer-side complete core assembly corrosion tests, corrosion failures frequently occur, failing to meet customer certification requirements, and exhibiting many insurmountable technical defects: First, the problem of galvanic corrosion is prominent. There is no finned low-potential anodic protection at the connection between the heat sink tube and the motherboard. Meanwhile, the customer's motherboard is generally made of high copper content alloy. A significant corrosion potential difference is formed between the tube material and the motherboard, which leads to preferential galvanic corrosion of the low-potential tube material. The joint is quickly perforated and leaked, directly causing the heat sink to fail. Secondly, the corrosion morphology is uncontrollable. Conventional pipe materials are prone to problems such as local pitting corrosion and non-layered penetration corrosion in SWAAT accelerated corrosion tests, which do not meet the customer's requirements for appearance and service life. The corrosion front expands in a disorderly manner and is very prone to early failure. Third, the composition control is crude, and recycled waste materials are commonly used in the production process. The elements such as Si, Fe, and Mn fluctuate greatly, which can easily cause Fe+Si and Fe+Mn to exceed the standard, forming a large number of brittle and harmful phases such as AlMnFeSi, which become the source of pitting corrosion and greatly reduce the corrosion resistance of the material. Fourth, the hot rolling process is unreasonable. Conventional hot rolling passes are too few and the final rolling temperature is too high, resulting in severe mixed grains, fine grains mixed, poor uniformity, obvious Brownian bands in the brazed structure, and easy corrosion to penetrate rapidly along the Brownian bands, making it difficult to achieve controllable layered corrosion. Fifth, the mechanical properties are insufficient. The yield strength of conventional pipe materials after brazing is low and the strength reserve is insufficient. They are prone to deformation and cracking under vibration, pressure and thermal cycling conditions, and the reliability is difficult to meet the requirements of high-end customers. Sixth, the coating rate is not easily controlled, the thickness of the leather material fluctuates greatly, and the consistency of the composite interface is poor, which further aggravates the risk of local corrosion and cannot meet the requirements of high-end heat sinks for material consistency and stability.

[0004] Therefore, it is necessary to invent an aluminum-based composite radiator tube material and manufacturing process with controllable layered corrosion to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide an aluminum-based composite radiator tube material with controllable layered corrosion and its preparation process, so as to solve the problems of poor adaptability to galvanic corrosion, uncontrollable corrosion morphology, uneven structure, large fluctuation in composition, low mechanical properties, and poor coating stability of aluminum-based composite radiator tube materials in the above-mentioned technologies.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a layered corrosion controllable aluminum-based composite radiator tube material, wherein the tube material is a three-layer composite structure of 4045 sheath material, modified 3Z23 core material, and 4045 sheath material; the core material is one of 3Z23, 3Z23E, 3Z23M, and 3Z23ME, and is produced using narrow-range composition control with no recycled waste, satisfying Fe+Si≤0.35% and Fe+Mn≤1.75%; the Cu content of 3Z23E and 3Z23ME is 0.60~0.70%; and the mass percentage of the chemical composition of the core material is as follows: 3Z23: Si 0.06~0.12%, Fe 0.20~0.28%, Cu 0.40~0.50%, Mn 1.45~1.55%, Ti 0.08~0.15%, Mg≤0.05%, Zn≤0.05%, Zr≤0.05%, balance Al; 3Z23E: Si 0.06~0.12%, Fe 0.20~0.28%, Cu 0.60~0.70%, Mn 1.45~1.55%, Ti 0.08~0.15%, Mg≤0.05%, Zn≤0.05%, Zr≤0.05%, balance Al; 3Z23M: Si≤0.08%, Fe0.10~0.18%, Cu0.30~0.40%, Mn1.35~1.45%, Ti0.08~0.15%, Mg≤0.05%, Zn≤0.05%, Zr≤0.05%, balance Al; 3Z23ME: Si≤0.08%, Fe0.10~0.18%, Cu0.60~0.70%, Mn1.35~1.45%, Ti0.08~0.15%, Mg≤0.05%, Zn≤0.05%, Zr≤0.05%, balance Al.

[0007] After brazing, the metallographic structure of the pipe material consists of coarse, elongated crystals along the rolling direction, with uniform structure in the thickness direction and no fine grains mixed in. In the SWAAT corrosion test, the pipe material exhibits a transverse layered corrosion morphology, with a corrosion depth of no more than 50% of the pipe material thickness after 21 days, and no obvious pitting corrosion.

[0008] Preferably, the composite layer coverage rate is stably controlled at 10.0%~11.0%, and the tube material corresponding to the Cu series 3Z23E and 3Z23ME core materials shows a significant weakening of the Brown band after brazing, and the corrosion front is more uniform and controllable.

[0009] Preferably, the finished pipe material has a thickness of 0.23 mm, an H24 state, and a coverage rate of 10.0% to 11.0%.

[0010] Preferably, the pipe material has a yield strength > 50 MPa after brazing, a tensile strength of 195-210 MPa before brazing, and an elongation of 12%-18%.

[0011] Preferably, it includes the following steps: S1. Core casting: Heterogeneous casting method is adopted, with ingot thickness of 340~360mm; casting temperature of 3Z23 / 3Z23E is 700~720℃ and speed is 44~50mm / min; casting temperature of 3Z23M / 3Z23ME is 705~725℃ and speed is 40~48mm / min; cooling water flow rate is 380~410m³ / h, and no independent homogenization process is performed after casting; S2. Assembly and welding: The outer material is 4045 with a thickness of 43~47mm, and the core material has a thickness of 320~330mm. They are assembled and welded to form a composite ingot. S3. Composite hot rolling: The composite ingot is heated to 480-510℃ and held for 2-18 hours. It is rolled in 26-30 passes with an initial rolling temperature of 450-490℃, a final rolling temperature of ≤360℃, and a final rolling thickness of 8.0-9.0 mm. S4. Cold rolling: Precision rolling of hot-rolled billets in multiple passes to a finished thickness of 0.23mm; S5. Finished product annealing: Softening annealing is carried out in the temperature range of 200~310℃ to obtain H24 state; S6. Sampling and verification: The mechanical properties, metallographic structure, SWAAT corrosion performance and dimensional appearance of the finished product are tested to ensure that there is lamellar corrosion, no pitting corrosion and corrosion depth ≤ 50% of the wall thickness.

[0012] Preferably, the composite hot rolling in S3 is preferably carried out in 28 passes with a large reduction to obtain uniform coarse long strip crystals and eliminate the mixing of mixed crystals and fine crystals.

[0013] Preferably, after the finished product is annealed in S5, the tube is brazed, and there are obvious Brownian bands in the metallographic structure, with no fine grains mixed in the thickness direction.

[0014] Preferably, the SWAAT corrosion test cycle in S6 includes 7 days, 14 days, and 21 days. The corrosion depth is controlled at 30-50% after 21 days, mainly consisting of pure lamellar corrosion, without pitting corrosion or non-lamellar penetrating corrosion.

[0015] Preferably, the 3Z23ME core material, after being prepared by the process, exhibits the optimal SWAAT corrosion depth after 21 days, which is 30-35% of the wall thickness, making it suitable for high Cu motherboard galvanic corrosion conditions.

[0016] Preferably, the tubing is used for the radiator core, is compatible with copper-containing motherboards, and has resistance to galvanic corrosion.

[0017] The technical effects and advantages provided by the present invention in the above technical solution are as follows: 1. This invention utilizes a core material casting process with "no recycled waste + narrow-range composition control" to strictly control Fe+Si≤0.35% and Fe+Mn≤1.75%, significantly reducing the formation of harmful phases such as AlMnFeSi, fundamentally eliminating pitting corrosion initiation sources, and enabling the pipe material to exhibit a pure lamellar corrosion morphology in the SWAAT corrosion test, with a corrosion depth ≤50% of the wall thickness after 21 days. This solves the problem of non-lamellar corrosion and local pitting corrosion failure caused by large fluctuations in impurities in conventional pipe materials. 2. By increasing the number of composite hot rolling passes to 26-30 (preferably 28 passes) and controlling the final rolling temperature to ≤360℃, compared with the conventional 23-pass, final rolling ≈380℃ process, the present invention significantly refines the grain orientation, eliminates mixed grain phenomenon, and obtains a coarse elongated grain structure along the rolling direction after brazing, with uniform thickness direction and no fine grain mixture, thereby improving the consistency of the tube structure and the uniformity and controllability of the corrosion front. 3. This invention develops 3Z23M and 3Z23ME series core materials with low Fe, low Si, and partitioned Cu content, especially by increasing the Cu content to 0.60~0.70%, which matches the mainstream Cu-containing motherboard operating conditions in the market. This effectively reduces the corrosion potential difference between the tube and the motherboard and significantly improves the resistance to galvanic corrosion. At the same time, the Brown band is significantly weakened after brazing the Cu-added tube materials, avoiding the risk of corrosion preferentially penetrating along the Brown band. 4. By stabilizing the coating rate at 10.0~11.0%, compared to the 11.3% coating rate of conventional mass-produced pipe materials, the composite interface is more stable and the skin distribution is more uniform, ensuring the overall corrosion resistance consistency of the pipe material after brazing; at the same time, the post-weld yield strength is consistently >50MPa (compared to only 45~50MPa for conventional pipe materials), which improves corrosion resistance while ensuring the mechanical reliability of the pipe material; 5. The four core materials (3Z23, 3Z23E, 3Z23M, and 3Z23ME) provided by this invention can be flexibly adapted to the Cu content and corrosion level requirements of different customers' motherboards. Among them, the 3Z23ME core material has the best corrosion depth (30~35% of wall thickness) in the 21-day SWAAT test, which is significantly better than the 38~42% of conventional tubing materials. It achieves precise control of the layered corrosion depth and corrosion rate, and meets the usage requirements of high-reliability heat sink cores. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the pipe material preparation process of the present invention; Figure 2 This is a comparative schematic diagram of the metallographic structure of the composite pipe material of the present invention; Figure 3 This is a schematic diagram showing the SWAAT corrosion test comparison of the composite pipe material of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way.

[0020] Example 1: 4045 / 3Z23 / 4045-0.23-H24 composite pipe material Step 1. Core Material Casting: 3Z23 core material is used, with no recycled waste. The chemical composition by mass percentage is controlled as follows: Si 0.09%, Fe 0.24%, Cu 0.45%, Mn 1.50%, Ti 0.11%, Mg≤0.05%, Zn≤0.05%, Zr≤0.05%, with the balance being Al. Key performance indicators: Fe+Si=0.33%≤0.35%, Fe+Mn=1.74%≤1.75%; Casting process parameters: Ingot thickness: 350mm; Casting temperature: 710℃; Casting speed: 47mm / min; Cooling water flow rate: 395m³ / h; Step 2. Ingot assembly and welding: Three-layer composite structure: 4045 outer material, 3Z23 core material, and 4045 outer material. The thickness of the 4045 outer material is 45mm; the thickness of the core material is 325mm; the coverage rate is 10.5%. The outer material and the core material are assembled and welded to form a complete composite ingot. Step 3. Composite hot rolling: Heating temperature: 495℃, holding time: 6h; initial rolling temperature: 470℃; rolling passes: 28 passes (large reduction); final rolling temperature: 350℃ (≤360℃); final rolling exit thickness: 8.5mm; Step 4. Cold rolling: The hot-rolled billet is precision rolled in multiple passes to a finished thickness of 0.23 mm; Step 5. Annealing: Perform softening annealing at 280℃ to obtain the H24 state; Step Six. Sampling and Verification (see attached document) Figure 2 , Figure 3 ) Metallographic structure ( Figure 2 The polarized microstructure after brazing consists of coarse, elongated crystals along the rolling direction, with an average grain size of 258 μm; the thickness direction is uniform with no fine grains mixed in; and the white light microstructure after brazing shows obvious Brownian bands.

[0021] Mechanical properties: Tensile strength before brazing: 205 MPa, yield strength: 180 MPa, elongation: 13%; Yield strength after brazing: 56 MPa (>50 MPa).

[0022] SWAAT corrosion test ( Figure 3 Corrosion depth at 7 days: 18-20%; at 14 days: 35-38%; at 21 days: 40%; corrosion morphology is pure lamellar with no pitting. Example 2: 4045 / 3Z23E / 4045-0.23-H24 composite pipe material Core material casting: 3Z23E core material is used, with no recycled waste. The chemical composition by mass percentage is controlled as follows: Si 0.09%, Fe 0.24%, Cu 0.65%, Mn 1.50%, Ti 0.11%, Mg≤0.05%, Zn≤0.05%, Zr≤0.05%, with the balance being Al. Key indicators are controlled as follows: Fe+Si=0.33%≤0.35%, Fe+Mn=1.74%≤1.75%. Casting process parameters are the same as in Example 1: 350mm ingot, 710℃, 47mm / min, 395m³ / h.

[0023] The processes of ingot welding (coverage rate 10.5%), composite hot rolling (28 passes, final rolling at 350°C), cold rolling (to 0.23 mm), and annealing (280°C, H24) were all the same as in Example 1.

[0024] Performance testing (corresponding appendix) Figure 2 , Figure 3 ) Metallographic structure ( Figure 2 ): The polarized structure after brazing is coarse, elongated crystals with an average grain size of 266 μm; the thickness direction is uniform; the Brown bands in the white light structure are significantly weakened after brazing.

[0025] Mechanical properties: Tensile strength before brazing: 200 MPa, yield strength: 175 MPa, elongation: 13%; Yield strength after brazing: 58 MPa (>50 MPa).

[0026] SWAAT corrosion test ( Figure 3 ): 7-day corrosion depth 18-21%, 14-day corrosion depth 24-27%, 21-day corrosion depth 47%; corrosion morphology is pure layered, without pitting corrosion, suitable for high Cu motherboard conditions. Example 3: 4045 / 3Z23M / 4045-0.23-H24 composite pipe material Core casting: 3Z23M core material is used, with no recycled waste. The chemical composition by mass percentage is controlled as follows: Si 0.06%, Fe 0.14%, Cu 0.35%, Mn 1.40%, Ti 0.11%, Mg≤0.05%, Zn≤0.05%, Zr≤0.05%, with the balance being Al. Key performance indicators are controlled as follows: Fe+Si=0.20%≤0.35%, Fe+Mn=1.54%≤1.75%. Casting process parameters: Ingot thickness: 350mm; Casting speed: 44mm / min; Cooling water flow rate: 395m³ / h. The processes of ingot welding (coverage rate 10.5%), composite hot rolling (28 passes, final rolling at 350°C), cold rolling (to 0.23 mm), and annealing (280°C, H24) are all the same as in Example 1.

[0027] Performance testing (corresponding appendix) Figure 2 , Figure 3 ) Metallographic structure ( Figure 2 The polarized structure after brazing is characterized by coarse, elongated crystals with an average grain size of 290 μm; the thickness direction is uniform; and the Brownian bands in the white light structure after brazing are more obvious.

[0028] Mechanical properties: Tensile strength before brazing: 205 MPa, yield strength: 195 MPa, elongation: 16%; Yield strength after brazing: 53 MPa (>50 MPa).

[0029] SWAAT corrosion test ( Figure 3 ): 7-day corrosion depth 20-23%, 14-day corrosion depth 33-36%, 21-day corrosion depth 45%; corrosion morphology is pure lamellar with no pitting.

[0030] Example 4: 4045 / 3Z23ME / 4045-0.23-H24 composite pipe material Core casting: 3Z23ME core material is used, with no recycled waste. The chemical composition by mass percentage is controlled as follows: Si 0.06%, Fe 0.14%, Cu 0.65%, Mn 1.40%, Ti 0.11%, Mg≤0.05%, Zn≤0.05%, Zr≤0.05%, with the balance being Al. Key indicators are controlled as follows: Fe+Si=0.20%≤0.35%, Fe+Mn=1.54%≤1.75%. Casting process parameters are the same as in Example 3: 350mm ingot, 715℃, 44mm / min, 395m³ / h.

[0031] The process of ingot welding (coverage rate 10.5%), composite hot rolling (28 passes, final rolling 345℃), cold rolling (to 0.23mm), and annealing (280℃, H24) is basically the same as that in Example 1, except that the final rolling temperature is optimized to 345℃ to further refine the microstructure.

[0032] Performance testing (corresponding appendix) Figure 2 , Figure 3 ) Metallographic structure ( Figure 2 The brazed microstructure under polarized light is characterized by coarse, elongated crystals with an average grain size of approximately 280 μm; the thickness direction is uniform; the brazed microstructure under white light exhibits extremely weak Brownian bands and a more uniform corrosion front. Mechanical properties: Tensile strength before brazing: 205 MPa, yield strength: 198 MPa, elongation: 17%; Yield strength after brazing: 58 MPa (>50 MPa).

[0033] SWAAT corrosion test ( Figure 3 ): 7-day corrosion depth 18-21%, 14-day corrosion depth 30-35%, 21-day corrosion depth 30-35%; the corrosion morphology is pure layered, without pitting corrosion, with the best resistance to galvanic corrosion, and is suitable for high Cu motherboard conditions.

[0034] Comparative Example: Conventional 4045 / 3Z23 / 4045-0.23-H24 Composite Pipe Composition control: The use of recycled waste materials results in large fluctuations in Si, Fe, and Mn elements, with Fe+Si easily exceeding the standard.

[0035] Preparation process: The composite hot rolling process uses 23 passes with a final rolling temperature of approximately 380℃; the coverage rate is approximately 11.3%, with significant fluctuations.

[0036] Performance testing: Metallographic structure: Mixed grain phenomenon exists after brazing, with obvious fine grain mixing and clear Brown bands; Mechanical properties: Yield strength after brazing is only 45-50MPa; SWAAT corrosion test: 21-day corrosion depth is 38-42%, prone to pitting corrosion and non-layer penetration corrosion, and severe galvanic corrosion when matched with high Cu motherboard.

[0037] A comprehensive comparative analysis of the above embodiments and comparative examples shows that the present invention achieves the following through narrow composition control without recycled waste, low-temperature final rolling of 26-30 passes (preferably 28 passes), stable control of 10.0-11.0% coverage rate, and Cu content gradient design: The brazed microstructure is uniform and free of fine grains, providing an organizational basis for controllable lamellar corrosion. The corrosion morphology is mainly pure lamellar with no pitting corrosion, and the corrosion depth after 21 days is ≤50% of the wall thickness; After brazing, the yield strength is consistently >50MPa, and the mechanical properties are superior to those of conventional products. The Cu-enhanced series (especially 3Z23ME) tubing exhibits reduced Brownian banding and significantly improved resistance to galvanic corrosion, making it suitable for high-Cu motherboard applications and resolving the issue of easy corrosion failure in conventional tubing.

[0038] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0039] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A layered corrosion controllable aluminum-based composite radiator tube material, characterized in that, The tubing is a three-layer composite structure consisting of 4045 sheath, modified 3Z23 core material, and 4045 sheath. The core material is one of 3Z23, 3Z23E, 3Z23M, and 3Z23ME, and its composition is controlled within a narrow range using non-recycled waste materials, satisfying Fe+Si≤0.35% and Fe+Mn≤1.75%. The Cu content of the 3Z23E and 3Z23ME is 0.60~0.70%. The chemical composition (mass percentage) of the core material is as follows: 3Z23: Si 0.06~0.12%, Fe 0.20~0.28%, Cu 0.40~0.50%, Mn 1.45~1.55%, Ti 0.08~0.15%, Mg≤0.05%, Zn≤0.05%, Zr≤0.05%, balance Al; 3Z23E: Si 0.06~0.12%, Fe 0.20~0.28%, Cu 0.60~0.70%, Mn 1.45~1.55%, Ti 0.08~0.15%, Mg≤0.05%, Zn≤0.05%, Zr≤0.05%, balance Al; 3Z23M: Si≤0.08%, Fe0.10~0.18%, Cu0.30~0.40%, Mn1.35~1.45%, Ti0.08~0.15%, Mg≤0.05%, Zn≤0.05%, Zr≤0.05%, balance Al; 3Z23ME: Si≤0.08%, Fe0.10~0.18%, Cu0.60~0.70%, Mn1.35~1.45%, Ti0.08~0.15%, Mg≤0.05%, Zn≤0.05%, Zr≤0.05%, balance Al. After brazing, the metallographic structure of the pipe material consists of coarse, elongated crystals along the rolling direction, with uniform structure in the thickness direction and no fine grains mixed in. In the SWAAT corrosion test, the pipe material exhibits a transverse layered corrosion morphology, with a corrosion depth of no more than 50% of the pipe material thickness after 21 days, and no obvious pitting corrosion.

2. The aluminum-based composite radiator tube material with controllable layered corrosion according to claim 1, characterized in that: The composite layer coverage rate is stably controlled at 10.0%~11.0%, and the tubes corresponding to the Cu series 3Z23E and 3Z23ME core materials show a significant weakening of the Brown band after brazing, and the corrosion front is more uniform and controllable.

3. The aluminum-based composite radiator tube material with controllable layered corrosion according to claim 1, characterized in that: The finished pipe material has a thickness of 0.23 mm, an H24 temper, and a coverage rate of 10.0% to 11.0%.

4. The aluminum-based composite radiator tube material with controllable layered corrosion according to claim 3, characterized in that: The pipe material has a yield strength >50MPa after brazing, a tensile strength of 195-210MPa before brazing, and an elongation of 12%-18%.

5. A process for preparing the aluminum-based composite radiator tube material with controllable layered corrosion as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Core casting: Heterogeneous casting method is adopted, with ingot thickness of 340~360mm; casting temperature of 3Z23 / 3Z23E is 700~720℃ and speed is 44~50mm / min; casting temperature of 3Z23M / 3Z23ME is 705~725℃ and speed is 40~48mm / min; cooling water flow rate is 380~410m³ / h, and no independent homogenization process is performed after casting; S2. Assembly and welding: The outer material is 4045 with a thickness of 43~47mm, and the core material has a thickness of 320~330mm. They are assembled and welded to form a composite ingot. S3. Composite hot rolling: The composite ingot is heated to 480-510℃ and held for 2-18 hours. It is rolled in 26-30 passes with an initial rolling temperature of 450-490℃, a final rolling temperature of ≤360℃, and a final rolling thickness of 8.0-9.0 mm. S4. Cold rolling: Precision rolling of hot-rolled billets in multiple passes to a finished thickness of 0.23mm; S5. Finished product annealing: Softening annealing is carried out in the temperature range of 200~310℃ to obtain H24 state; S6. Sampling and verification: The mechanical properties, metallographic structure, SWAAT corrosion performance and dimensional appearance of the finished product are tested to ensure that there is lamellar corrosion, no pitting corrosion and corrosion depth ≤ 50% of the wall thickness.

6. The preparation process of a layered corrosion controllable aluminum-based composite radiator tube according to claim 5, characterized in that: In the S3 process, the composite hot rolling is preferably carried out in 28 passes with a large reduction to obtain uniform, coarse, long strip crystals and eliminate the mixing of mixed and fine crystals.

7. The preparation process of a layered corrosion controllable aluminum-based composite radiator tube according to claim 5, characterized in that: After the finished product in S5 is annealed, the tube is brazed, and there are obvious Brownian bands in the metallographic structure, with no fine grains mixed in the thickness direction.

8. The preparation process of a layered corrosion controllable aluminum-based composite radiator tube according to claim 5, characterized in that: The SWAAT corrosion test cycle in S6 includes 7 days, 14 days, and 21 days. The corrosion depth is controlled at 30-50% after 21 days, mainly consisting of pure lamellar corrosion, without pitting corrosion or non-lamellar penetrating corrosion.

9. The preparation process of a layered corrosion controllable aluminum-based composite radiator tube according to claim 5, characterized in that: After processing, the 3Z23ME core material exhibits the optimal SWAAT corrosion depth of 30-35% of the wall thickness after 21 days, making it suitable for high-Cu motherboard galvanic corrosion conditions.

10. The preparation process of a layered corrosion controllable aluminum-based composite radiator tube according to claim 1, characterized in that: The tubing is used for the radiator core, is compatible with copper-containing motherboards, and has resistance to galvanic corrosion.

Images