Aluminum clad copper strip production process
By inserting copper rods into hollow aluminum rods in a protective gas environment and then performing rolling, drawing, pressing, and annealing processes, the problem of loose bonding in aluminum-clad copper strips was solved, achieving higher bonding strength and wire uniformity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG DINGXIN MATERIAL TECH CO LTD
- Filing Date
- 2026-04-10
- Publication Date
- 2026-06-05
AI Technical Summary
In the existing aluminum-clad copper strip production process, it is difficult to achieve a strong metallurgical bond at the copper-aluminum interface, which easily leads to delamination and loose bonding, resulting in unstable wire performance.
A copper-clad copper strip is formed by inserting a copper rod into a hollow aluminum rod in a protective gas atmosphere and then performing rolling, drawing, and pressing processes. The strip is then annealed at a specific temperature to enhance the copper-aluminum bonding strength.
It improves the bonding strength and wire deformation uniformity of aluminum-clad copper strip, reduces bonding gaps, and enhances wire strength.
Smart Images
Figure CN122142121A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of metal composite material processing, and specifically relates to a production process for aluminum-clad copper strip suitable for module packaging. Background Technology
[0002] In recent years, with the development of the new energy economy, the demand for power devices in applications such as new energy and energy storage, communications and electronics has gradually increased, and aluminum-clad copper strips offer lower costs and more complex application scenarios. Existing processes are mainly used in power device packaging, requiring high-strength bonding and stable wire performance. The current production process involves rolling, drawing, and pressing concentric copper-aluminum rods, which makes it difficult to achieve a strong metallurgical bond at the copper-aluminum interface, easily leading to delamination and loose bonding. Summary of the Invention
[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing a manufacturing process for aluminum-clad copper strip.
[0004] The objective of this invention is achieved through the following steps: 1. In a protective gas at a temperature of 340-420℃, insert a copper rod into a hollow aluminum rod, where the hollow diameter of the aluminum rod is equal to the outer diameter of the copper rod. 2. The aluminum-clad copper rod is rolled in a protective gas at a temperature of 380-440℃ for several passes to reduce its diameter and obtain an aluminum-clad copper billet rod. 3. The aluminum-clad copper billet is drawn in several passes to form an aluminum-clad copper wire; 4. The aluminum-clad copper wire is rolled in several passes to form aluminum-clad copper strip, with a rolling reduction rate of 10%-52%; 5. Annealing of aluminum-clad copper strip.
[0005] In a preferred embodiment of the present invention, the annealing temperature in step 5 is 310-365°C.
[0006] In a preferred embodiment of the present invention, in step 1, the outer diameter of the hollow aluminum rod is 90 mm, and the hollow diameter of the hollow aluminum rod is 20-50 mm; the outer diameter of the copper rod is 20-50 mm.
[0007] Compared with the prior art, the present invention has the following obvious advantages: Compared with the existing process, aluminum has better oxidation resistance than pure copper strip. The combination of hollow aluminum rod and copper rod has better bonding strength. Compared with the traditional process of using aluminum sheet to cover and extrude copper rod, there is no bonding gap of outer aluminum layer. During production and processing, the wire deforms evenly and the strength is increased. Attached Figure Description
[0008] Figure 1 This is the width of Comparison Example 1; Figure 2 This is the height of Comparative Example 1; Figure 3Width as in Example 1; Figure 4 The height is as described in Example 1; Figure 5 This is the width of Comparison Example 2; Figure 6 This is the height of Comparative Example 2; Figure 7 The width is the same as in Example 2; Figure 8 The height is as shown in Example 2; Figure 9 This is the width of Comparative Example 3; Figure 10 This is the height of Comparative Example 3; Figure 11 The width is the same as in Example 3; Figure 12 The height is for Example 3. Detailed Implementation
[0009] Example 1 1. The raw materials are a 40mm diameter copper rod and a 90mm diameter hollow aluminum rod with an internal hollow diameter of 40mm. The aluminum content in the hollow aluminum rod is 99.99%, and the total content of other impurities is ≤0.01%. The copper content in the copper rod is 99.99%, and the total content of other impurities is ≤0.01%. The copper rod is soaked in 6% dilute sulfuric acid for 3 minutes, then soaked in deionized water for 5 minutes, and then dried with compressed air. The inner hole of the hollow aluminum rod is sanded with sandpaper, then cleaned with compressed air. The copper rod is then placed inside the hollow aluminum rod for encapsulation to form a copper-aluminum composite material. The material is heated to 410℃ in a sealed high-temperature oven under argon protection. After holding the hollow aluminum rod with the copper rod inside for 2 hours, the temperature is reduced to 30℃ at a rate of 5℃ per minute. 2. The copper-aluminum composite material with a diameter of 90mm was heated to 420℃ in a high-temperature oven and held for 4 hours before being rolled to obtain an aluminum-clad copper billet rod, as shown in Table 1.
[0010]
[0011] During the process, aluminum-clad copper rods with a diameter of φ90mm are rolled down to φ5.01mm, with a total reduction coefficient of 94.43%. The inner copper rod diameter is 2.23mm, and the aluminum layer thickness of the copper-aluminum composite material is 1.39mm.
[0012] 3. The copper-aluminum composite material with a diameter of 5.01 mm was drawn to 1.347 mm through 23 drawing passes to form an aluminum-clad copper wire; the diameter, aluminum layer thickness, cross-sectional area, and reduction factor after each drawing are shown in Table 2.
[0013]
[0014] 4. The copper-aluminum composite material with a diameter of 1.347mm was rolled to 2x0.3mm through 5 rolling passes. The rolling thickness is shown in Table 3.
[0015]
[0016] 5. Annealing of aluminum-clad copper strip, The rolled composite material is rewound onto a hollow aluminum shaft with a diameter of 50 mm and a width of 128 mm. The composite material is placed in a high-temperature oven and heated to 100 °C at a rate of 6 °C per minute. After holding at this temperature for 10 minutes, the temperature is increased to 365 °C at a rate of 10 °C per minute and held for 1 hour. Then, the material is cooled in the oven at a rate of 15 °C per minute until it reaches 30 °C, at which point the product can be rewound.
[0017] Comparative Example 1: The process of Comparative Example 1 is similar to that of Example 1, with steps 1 to 3 being the same. In step 4, the copper-aluminum composite material with a diameter of 1.347 mm is rolled twice and then drawn and shaped through a die with a die hole size of 2x0.3 mm to achieve a product size of 2x0.3 mm. The reduction rate is shown in Table 4. After rolling, the wire is drawn through a special-shaped die with a hole diameter of 2 mm and a thickness of 0.3 mm at a drawing speed of 5 m / min and then wound onto a take-up spool.
[0018]
[0019] Step 5: The rolled composite material is passed through a horizontal annealing furnace. The take-up spool is placed on one side of the inlet of the horizontal annealing furnace with automatic wire feeding. The material passes through an electric heating resistance wire heating furnace with a furnace length of 150cm and a temperature of 440℃ at a speed of 4m / min to obtain the product with the target performance.
[0020] Data detection of Example 1 and Comparative Example 1: Testing specifications: 2 x 0.3 mm.
[0021] 1. Wire deformation uniformity Testing method: Place the wire into the vacuum observation chamber of a scanning electron microscope and use a scanning electron microscope.
[0022] Testing equipment: Hitachi S-3400 Detection parameters: 12.0mm x 35x / 10.3mm x 150mm Test results: The width of Comparative Example 1 is 1.87 mm and the thickness is 303 μm. The width of Example 1 is 2 mm and the thickness is 299 μm.
[0023] 2. Strength: Testing method: Clamp the wire to both ends of the universal material tester.
[0024] Testing equipment: Electronic universal testing machine 810 Test parameters: Test speed 80mm / min, sampling length 10cm Test results: See Table 5 Table 5. Strength test results for Comparative Example 1 and Example 1
[0025] Example 2: 1. The raw materials are a 26mm diameter copper rod and a 90mm diameter hollow aluminum rod with an internal hollow diameter of 26mm. The aluminum content in the hollow aluminum rod is 99.99%, and the total content of other impurities is ≤0.01%. The copper content in the copper rod is 99.99%, and the total content of other impurities is ≤0.01%. The copper rod is soaked in 6% dilute sulfuric acid for 3 minutes, then soaked in deionized water for 5 minutes, and then dried with compressed air. The inner hole of the hollow aluminum rod is polished with sandpaper, then cleaned with compressed air. The copper rod is then placed inside the hollow aluminum rod for encapsulation to form a copper-aluminum composite material. The material is heated to 410℃ in a sealed high-temperature oven under argon protection. After holding the hollow aluminum rod with the copper rod inside for 2 hours, the temperature is reduced to 30℃ at a rate of 5℃ per minute. 2. The copper-aluminum composite material with a diameter of 90mm was heated to 420℃ in a high-temperature oven and held for 4 hours before being rolled to obtain an aluminum-clad copper billet rod, as shown in Table 6.
[0026] Table 6. Variation of Rolled Outer Diameter in Example 2
[0027] 3. The copper-aluminum composite material with a diameter of 5.01 mm was drawn to 0.744 mm through 34 drawing passes to form an aluminum-clad copper wire; the diameter, aluminum layer thickness, cross-sectional area, and reduction factor after each drawing are shown in Table 7.
[0028] Table 7. Variation of Drawing Outer Diameter in Example 2
[0029] 4. The copper-aluminum composite material with a diameter of 0.744mm was rolled to 1.5x0.2mm through 5 rolling passes. The rolling thickness is shown in Table 8.
[0030] Table 8. Variation of Rolling Width in Example 2
[0031] 5. Annealing of aluminum-clad copper strip, The rolled composite material is rewound onto a hollow aluminum shaft with a diameter of 50 mm and a width of 128 mm. The composite material is placed in a high-temperature oven and heated to 100 °C at a rate of 6 °C per minute. After holding at this temperature for 10 minutes, the temperature is increased to 355 °C at a rate of 10 °C per minute and held for 1 hour. Then, the material is cooled in the oven at a rate of 15 °C per minute until it reaches 30 °C, at which point the product can be rewound.
[0032] The process of Comparative Example 2 is similar to that of Example 2, with steps 1 to 3 being the same. In step 4, the copper-aluminum composite material with a diameter of 0.744 mm is rolled twice and then drawn and shaped through a die with a die hole size of 1.5 x 0.2 mm to achieve a product size of 1.5 x 0.2 mm. The reduction rate is shown in Table 8. After rolling, the wire is drawn through a special-shaped die with a hole size of 1.5 mm and a thickness of 0.2 mm at a drawing speed of 5 m / min and then wound onto a take-up spool.
[0033] Table 9 Comparative Example 2: Variation of Rolling Width
[0034] Step 5: The rolled composite material is passed through a horizontal annealing furnace. The take-up spool is placed on one side of the inlet of the horizontal annealing furnace with automatic wire feeding. The material passes through an electric heating resistance wire heating furnace with a furnace length of 150cm and a temperature of 420℃ at a speed of 5m / min to obtain the product with the target performance.
[0035] Data detection of Example 2 and Comparative Example 2: Inspection specifications: 1.5x0.2mm.
[0036] 6.1 Wire deformation uniformity Detection method: Place the wire into the vacuum chamber of a scanning electron microscope and use the scanning electron microscope. Testing equipment: Hitachi S-3400 Detection parameters: 6.1mm x 55x / 10.3mm x 150mm Test results: The width of Comparative Example 2 was 1.48~1.53mm and the thickness was 192~197μm. The width of Example 2 was 148~148mm and the thickness was 196~197μm.
[0037] 6.2 Strength: Testing method: Clamp the wire to both ends of the universal material tester. Testing equipment: Electronic universal testing machine 810 Test parameters: Test speed 80mm / min, sampling length 10cm Test results: See Table 10 Table 10 Strength test results for Comparative Example 2 and Example 2
[0038] Example 3: 1. The raw materials are a 45mm diameter copper rod and a 90mm diameter hollow aluminum rod with an internal hollow diameter of 45mm. The aluminum content in the hollow aluminum rod is 99.99%, and the total content of other impurities is ≤0.01%. The copper content in the copper rod is 99.99%, and the total content of other impurities is ≤0.01%. The copper rod is soaked in 6% dilute sulfuric acid for 3 minutes, then soaked in deionized water for 5 minutes, and then dried with compressed air. The inner hole of the hollow aluminum rod is sanded with sandpaper, then cleaned with compressed air. The copper rod is then placed inside the hollow aluminum rod for encapsulation to form a copper-aluminum composite material. The material is heated to 410℃ in a sealed high-temperature oven under argon protection. After holding the hollow aluminum rod with the copper rod inside for 2 hours, it is cooled to 30℃ at a rate of 5℃ per minute. 2. The copper-aluminum composite material with a diameter of 90mm was heated to 420℃ in a high-temperature oven and held for 4 hours before being rolled to obtain an aluminum-clad copper billet rod, as shown in Table 11.
[0039] Table 11. Variation of Rolled Outer Diameter in Example 3
[0040] 3. The copper-aluminum composite material with a diameter of 5.01 mm was drawn to 0.422 mm through 48 drawing passes to form an aluminum-clad copper wire; the diameter, aluminum layer thickness, cross-sectional area, and reduction factor after each drawing are shown in Table 12.
[0041] Table 12. Variation of outer diameter during drawing in Example 3.
[0042] 4. The copper-aluminum composite material with a diameter of 0.422mm was rolled to 1.0x0.1mm through 5 rolling passes. The rolling thickness is shown in Table 13.
[0043] Table 13 Variation of Rolling Width in Example 3
[0044] 5. Annealing of aluminum-clad copper strip, The rolled composite material is rewound onto a hollow aluminum shaft with a diameter of 50 mm and a width of 128 mm. The composite material is placed in a high-temperature oven and heated to 100 °C at a rate of 6 °C per minute. After holding at this temperature for 10 minutes, the temperature is increased to 350 °C at a rate of 10 °C per minute and held for 1 hour. Then, the material is cooled in the oven at a rate of 15 °C per minute until it reaches 30 °C, at which point the product can be rewound.
[0045] The process of Comparative Example 3 is similar to that of Example 3, with steps 1 to 3 being the same. In step 4, the copper-aluminum composite material with a diameter of 0.422 mm is rolled twice and then drawn and shaped through a die with a die hole size of 1x0.1 mm to achieve a product size of 1x0.1 mm. After rolling, the wire is drawn through a special-shaped die with a hole diameter of 1 mm and a thickness of 0.1 mm at a drawing speed of 8 m / min and wound onto a take-up spool.
[0046] Table 14 Comparative Example 3 Rolling Width Variation Table
[0047] Step 5: After the composite material is rolled, the take-up spool is placed on the inlet side of the horizontal annealing furnace with automatic wire feeding. The composite material is then passed through an electric heating resistance wire heating furnace with a furnace length of 150cm and a temperature of 420℃ at a speed of 7m / min.
[0048] Data detection of Example 3 and Comparative Example 3: Inspection specifications: 1.0 x 0.1 mm.
[0049] 1. Wire deformation uniformity Detection method: Place the wire into the vacuum chamber of a scanning electron microscope and use the scanning electron microscope. Testing equipment: Hitachi S-3400 Detection parameters: 6.7mm x 70x / 5.7mm x 600x Test results: The width of Comparative Example 3 was 967~972μm and the thickness was 99.5~101μm. The width of Example 3 was 998μm~1.00mm and the thickness was 100~100μm.
[0050] 6.2 Strength: Testing method: Clamp the wire to both ends of the universal material tester. Testing equipment: Electronic universal testing machine 810 Test parameters: Test speed 80mm / min, sampling length 10cm Test results: See Table 15 Table 15 Strength test results for Comparative Example 3 and Example 3
Claims
1. The production process of aluminum-clad copper strip involves the following steps: 1) In a protective gas at a temperature of 340-420℃, insert a copper rod into a hollow aluminum rod, where the hollow diameter of the aluminum rod is equal to the outer diameter of the copper rod. 2) The aluminum-clad copper rod is rolled in a protective gas at a temperature of 380-440℃ for several passes to reduce its diameter and obtain an aluminum-clad copper billet rod. 3) The aluminum-clad copper billet is drawn in several passes to form an aluminum-clad copper wire; 4) The aluminum-clad copper wire is rolled in several passes to form an aluminum-clad copper strip; 5) Annealing of aluminum-clad copper strip; Its characteristics are: In step 4, the reduction rate for each rolling pass is 10%-52%.
2. The aluminum-clad copper strip production process as described in claim 1, characterized in that: The annealing temperature in step 5 is 310-365℃.
3. The aluminum-clad copper strip production process as described in any one of claims 1 to 2, characterized in that: The hollow aluminum rod mentioned in step 1 has an outer diameter of 90 mm and a hollow diameter of 20~50 mm.
4. The aluminum-clad copper strip manufacturing process as described in any one of claims 1 to 2, characterized in that: The copper rod mentioned in step 1 has a copper purity greater than 99.99%, and the aluminum rod mentioned in step 1 has an aluminum purity greater than 99.99%.
5. The aluminum-clad copper strip manufacturing process as described in any one of claims 1 to 2, characterized in that: The copper rod described in step 1 is soaked in 6% dilute sulfuric acid for 3 minutes, then soaked in deionized water for 5 minutes, and then dried with compressed air. The hollow aluminum rod described in step 1 is polished with sandpaper to remove the inner hole, and then cleaned with compressed air.