A method for manufacturing a copper-based composite resistance seam welding wheel

Abstract

This application discloses a method for preparing a copper-based composite resistance seam welding wheel, belonging to the field of resistance seam welding technology. This application utilizes a cold spraying process to deposit Cu-Y2O3 composite powder on the rotating surface of a copper rod, achieving radial additive manufacturing of the copper rod. A Y2O3 dispersion-reinforced copper alloy coating is formed on the rotating surface of the copper rod, resulting in a welding wheel blank. The welding wheel blank is then annealed to remove stress, hot-forged, sliced, and machined to obtain the copper-based composite resistance seam welding wheel. The preparation method provided in this application is suitable for preparing large-size (diameter not less than 50mm) copper-based composite resistance seam welding wheels. The cold spraying process ensures that the coating on the rotating surface of the welding wheel contains dispersed yttrium oxide particles, giving the coating the necessary high-temperature softening resistance, electrical conductivity, and good wear resistance required for welding electrodes. The copper rod in the core of the welding wheel provides excellent electrical and thermal conductivity, and the raw material cost is relatively low.

Description

Technical Field

[0001] This application relates to the field of resistance seam welding technology, specifically to a method for preparing a copper-based composite resistance seam welding wheel. Background Technology

[0002] Resistance seam welding is a resistance welding method that uses a pair of roller electrodes (i.e., welding wheels) instead of the cylindrical electrodes used in resistance spot welding. During the welding process, the welding wheels press against the workpieces being welded, rotate, and drive the workpieces to move. Simultaneously, the welding wheels supply continuous or intermittent welding current to the workpieces, causing them to come into contact and generate heat, melting and welding them together. Currently, resistance seam welding is widely used in the welding of thin plates for sealed containers, mainly in industrial fields such as automotive fuel tanks, battery casings, and refrigerator and air conditioner compressor housings.

[0003] The material selection for resistance seam welding wheels is similar to that for resistance spot welding electrodes. Conventional resistance seam welding wheels commonly use chromium-zirconium copper or beryllium-cobalt copper alloys. However, when welding galvanized steel plates, the working surface of these alloys is prone to reaction with the galvanized layer, reducing the wheel's lifespan. While using yttrium oxide dispersion-strengthened copper alloy as the welding wheel material can effectively suppress alloying reactions on the working surface, increasing wheel lifespan and reducing production costs, the current mainstream method for producing yttrium oxide dispersion-strengthened copper alloy is internal oxidation, which cannot produce large-sized yttrium oxide dispersion-strengthened copper alloy blanks. This results in the current lack of corresponding large-sized dispersion-strengthened copper alloy welding wheels in the industry. Although copper wire electrode seam welding can solve this problem, the discarded copper wire after use increases production costs to some extent, and the introduced copper wire increases contact resistance during welding, raising energy consumption.

[0004] Therefore, how to manufacture high-quality, large-size copper alloy welding wheels is a problem that urgently needs to be solved in the field of resistance seam welding. Summary of the Invention

[0005] Based on the deficiencies of the existing technology, the purpose of this application is to provide a method for preparing a copper-based composite resistance seam welding wheel.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows: A method for preparing a copper-based composite resistance seam welding wheel includes the following steps: S1. After mixing copper powder and yttrium oxide powder, a mixture is obtained. The mixture is then subjected to acoustic resonance treatment to obtain a composite powder. S2. Perform surface pretreatment on the rotating surface of the copper rod; S3. The composite powder obtained in step S1 is deposited on the rotating surface of the copper rod after step S2 by cold spraying to form a coating and obtain the welding wheel blank. S4. The welding wheel blank obtained in step S3 is annealed and then hot-forged into shape, and then sliced ​​to obtain the copper-based composite resistance seam welding wheel.

[0007] In the above preparation method, steps S1 and S2 can be performed sequentially, or in reverse order (i.e., step S2 is performed first, then step S1), or they can be performed simultaneously.

[0008] This application utilizes a cold spraying process to deposit Cu-Y2O3 composite powder on the rotating surface of a copper rod, achieving radial additive manufacturing of the copper rod. A Y2O3 dispersion-reinforced copper alloy coating is formed on the rotating surface of the copper rod, resulting in a welding wheel blank. The welding wheel blank is then annealed to relieve stress, hot-forged, sliced, and machined to obtain a copper-based composite resistance seam welding wheel. The preparation method provided in this application is suitable for preparing large-size (diameter not less than 50mm) copper-based composite resistance seam welding wheels. Compared with existing copper wire electrode seam welding processes, the production cost of the preparation method in this application is lower. The cold spraying process in this application ensures that the coating on the rotating surface of the welding wheel contains dispersed yttrium oxide particles, giving the coating the necessary high-temperature softening resistance, electrical conductivity, and good wear resistance required for welding electrodes. The copper rod in the core of the welding wheel provides excellent electrical and thermal conductivity, and the raw material price is relatively low.

[0009] In a preferred embodiment of this application, in step S1, the mass ratio of the yttrium oxide powder to the copper powder is (0.01~0.1):1.

[0010] For example, the mass ratio of the yttrium oxide powder to the copper powder can be any one or any two of the following: 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1.

[0011] In a preferred embodiment of this application, in step S1, the particle size D50 of the yttrium oxide powder is 10~50 nm.

[0012] For example, the particle size D50 of the yttrium oxide powder can be any one or any combination of 10nm, 12nm, 15nm, 18nm, 20nm, 22nm, 25nm, 28nm, 30nm, 32nm, 35nm, 38nm, 40nm, 42nm, 45nm, 48nm, and 50nm.

[0013] In a preferred embodiment of this application, in step S1, the atmospheric environment of the acoustic resonance treatment is an inert atmosphere, which includes at least one of argon, nitrogen and helium, the acceleration of the acoustic resonance treatment is 30~90g, and the duration of the acoustic resonance treatment is 15~105min.

[0014] For example, the acceleration of the acoustic resonance treatment can be any one or any combination of two of the following values: 30g, 32g, 35g, 38g, 40g, 42g, 45g, 48g, 50g, 52g, 55g, 58g, 60g, 62g, 65g, 68g, 70g, 72g, 75g, 78g, 80g, 82g, 85g, 88g, and 90g; the duration of the acoustic resonance treatment can be any one or any combination of two of the following values: 15min, 18min, 20min, 22min, 25min, 28min, 30min, 32min, 35min, 40min, 45min, 50min, 55min, 60min, 65min, 70min, 75min, 80min, 85min, 90min, 95min, 100min, and 105min.

[0015] The inventors discovered through research that, prior to the cold spraying process, existing technologies generally involve mixing copper powder and yttrium oxide powder and then ball milling them. In contrast, this application involves mixing copper powder and yttrium oxide powder and then performing acoustic resonance treatment, which not only significantly shortens the required time but also better preserves the original powder morphology, reduces or avoids powder deformation, improves the density of the coating formed by cold spraying, and enhances the coating's resistance to high-temperature softening, electrical conductivity, and wear resistance.

[0016] In a preferred embodiment of this application, in step S2, the diameter of the copper rod is not less than 50 mm.

[0017] In a preferred embodiment of this application, the surface pretreatment method in step S2 includes, but is not limited to, sandblasting. Sandblasting the rotating surface of the copper rod before the cold spraying process can remove impurities and oxide films from the rotating surface, improving the bonding strength between the coating and the substrate copper rod.

[0018] In a preferred embodiment of this application, in step S3, the working gas of the cold spraying process is compressed air, the carrier gas temperature of the cold spraying process is 400~700℃, the carrier gas pressure of the cold spraying process is 3~5MPa, the powder feeding rate of the cold spraying process is 20~100g / min, and the spraying distance of the cold spraying process is 10~20mm.

[0019] For example, the carrier gas temperature of the cold spraying process can be any one or any combination of two of the following: 400℃, 420℃, 450℃, 480℃, 500℃, 520℃, 550℃, 580℃, 600℃, 620℃, 650℃, 680℃, and 700℃; the carrier gas pressure of the cold spraying process can be any one or any combination of two of the following: 3MPa, 3.2MPa, 3.5MPa, 3.8MPa, 4MPa, 4.2MPa, 4.5MPa, 4.8MPa, and 5MPa; the powder feeding rate of the cold spraying process can be 20g / min, 25g / min, or 3... The spraying distance of the cold spraying process can be any one or any two of the following values: 0 g / min, 35 g / min, 40 g / min, 45 g / min, 50 g / min, 55 g / min, 60 g / min, 65 g / min, 70 g / min, 75 g / min, 80 g / min, 85 g / min, 90 g / min, 95 g / min, 100 g / min;

[0020] In this application, the cold spraying process uses high-pressure gas and a nozzle to accelerate the composite powder to supersonic speed and spray it out, directly "colliding" with the surface of the workpiece (i.e., the rotating surface of the copper rod after step S2) to form a coating.

[0021] The composite powder particles remain solid during flight. The carrier gas temperature (400~700℃) is much lower than the melting point of the composite powder. The composite powder particles directly impact the workpiece surface. At the moment of high-speed impact, the particles undergo violent plastic deformation and embed themselves into the matrix like micro-forging, forming a dense coating.

[0022] In a preferred embodiment of this application, in step S3, the thickness of the coating is 20~50mm.

[0023] For example, the thickness of the coating can be any one or any combination of two of the following: 20mm, 22mm, 25mm, 28mm, 30mm, 32mm, 35mm, 38mm, 40mm, 42mm, 45mm, 48mm, and 50mm.

[0024] In a preferred embodiment of this application, in step S3, during the cold spraying process, the copper rod is rotated around its central axis, and the rotation speed of the copper rod is 20~100 rpm.

[0025] For example, the rotational speed of the copper rod can be any one or any combination of two of the following: 20 rpm, 25 rpm, 30 rpm, 35 rpm, 40 rpm, 45 rpm, 50 rpm, 55 rpm, 60 rpm, 65 rpm, 70 rpm, 75 rpm, 80 rpm, 85 rpm, 90 rpm, 95 rpm, and 100 rpm.

[0026] In a preferred embodiment of this application, in step S4, the annealing temperature is 300~600℃ and the annealing time is 2~4h.

[0027] For example, the annealing temperature can be any one or any combination of two of the following: 300℃, 320℃, 350℃, 380℃, 400℃, 420℃, 450℃, 480℃, 500℃, 520℃, 550℃, 580℃, and 600℃; the annealing time can be any one or any combination of two of the following: 2h, 2.5h, 3h, 3.5h, and 4h.

[0028] In a preferred embodiment of this application, in step S4, the hot forging temperature is 500~800℃, the hot forging time is 10~30min, and the strain rate of the hot forging is 1~10s. -1 .

[0029] For example, the hot forging temperature can be any one or any combination of two of the following: 500℃, 520℃, 550℃, 580℃, 600℃, 620℃, 650℃, 680℃, 700℃, 720℃, 750℃, 780℃, and 800℃; the strain rate of the hot forging can be 1s. -1 2s -1 3s -1 4s -1 5s -1 6s -1 7s -1 8s -1 9s -1 10s -1 The range of values ​​consisting of any one or any two of them.

[0030] In a preferred embodiment of this application, the Vickers hardness of the coating in the copper-based composite resistance seam welding wheel is not less than 140 HV. 500 The softening temperature of the coating is not less than 900℃, and the relative conductivity of the coating is not less than 85% IACS.

[0031] The resistivity of standard annealed copper at 20°C is 0.017241 Ω·mm. 2 The conductivity is 58.0 MS / m, defined as 100% IACS. In this application, the conductivity of the coating is expressed as the ratio of the coating's conductivity to this standard conductivity (58.0 MS / m) (i.e., %IACS).

[0032] Compared with the prior art, the beneficial effects of this application are as follows: The preparation method provided in this application is applicable to the preparation of large-sized (diameter not less than 50 mm) copper-based composite resistance seam welding wheels. Compared with existing copper wire electrode seam welding processes, the production cost of the preparation method in this application is lower. This application uses a cold spraying process to create a coating on the rotating surface of the welding wheel containing dispersed yttrium oxide particles, giving the coating the necessary high-temperature softening resistance, electrical conductivity, and good wear resistance required for welding electrodes. The copper rod in the core of the welding wheel provides excellent electrical and thermal conductivity, and the raw material price is relatively low. Attached Figure Description

[0033] Figure 1 This is a morphology diagram of the composite powder in Example 1 of this application; Figure 2 This is a morphology diagram of the composite powder in Comparative Example 1 of this application. Detailed Implementation

[0034] To better illustrate the purpose, technical solution, and advantages of this application, the following description, in conjunction with specific embodiments and comparative examples, aims to provide a detailed understanding of the content of this application, rather than limiting it. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this application. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this application are all commonly used reagents and instruments.

[0035] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this application are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0036] Example 1 This embodiment provides a method for preparing a copper-based composite resistance seam welding wheel, including the following steps: S1. Yttrium oxide powder (particle size D50 of 30nm) and copper powder (particle size D50 of 3μm) are mixed at a mass ratio of 0.02:1 to obtain a mixture. The mixture is placed in an acoustic resonance device and treated with acoustic resonance at an acceleration of 40g for 30min in an argon atmosphere to obtain a composite powder. S2. Take a copper rod with a diameter of 50mm and sandblast the rotating surface of the copper rod. S3. The composite powder obtained in step S1 is loaded into the powder feeding tank of the cold spraying equipment. The copper rod processed in step S2 is fixed on the three-jaw chuck. Under the drive of the motor, the copper rod rotates around its own central axis. Using nitrogen as the working gas, the composite powder obtained in step S1 is cold sprayed onto the rotating surface of the copper rod through the cold spraying equipment to form a coating and obtain a welding wheel blank. During the cold spraying process, the carrier gas temperature is 600℃, the carrier gas pressure is 3.5MPa, the powder feeding rate is 20g / min, the spraying distance is 15mm, and the rotation speed of the copper rod is 25rpm. S4. Anneal the welding wheel blank obtained in step S3 at 400°C for 2 hours under argon protection, and then anneal it at 700°C for 5 seconds. -1 The copper-based composite resistance seam welding wheel is obtained by hot forging at a hot forging strain rate of 15 min and then slicing along a direction perpendicular to the central axis of the copper rod.

[0037] Example 2 This embodiment provides a method for preparing a copper-based composite resistance seam welding wheel, including the following steps: S1. Yttrium oxide powder and copper powder are mixed at a mass ratio of 0.05:1 to obtain a mixture. The mixture is placed in an acoustic resonance device and treated with acoustic resonance at an acceleration of 60g for 45 minutes in an argon atmosphere to obtain a composite powder. S2. Take a copper rod with a diameter of 50mm and sandblast the rotating surface of the copper rod. S3. The composite powder obtained in step S1 is loaded into the powder feeding tank of the cold spraying equipment. The copper rod processed in step S2 is fixed on a three-jaw chuck. Under the drive of the motor, the copper rod rotates around its own central axis. Using nitrogen as the working gas, the composite powder obtained in step S1 is cold sprayed onto the rotating surface of the copper rod through the cold spraying equipment to form a coating and obtain a welding wheel blank. During the cold spraying process, the carrier gas temperature is 500℃, the carrier gas pressure is 3.5MPa, the powder feeding rate is 20g / min, the spraying distance is 15mm, and the rotation speed of the copper rod is 25rpm. S4. Anneal the welding wheel blank obtained in step S3 at 300°C for 2 hours under argon protection, and then anneal it at 600°C for 5 seconds. -1 The copper-based composite resistance seam welding wheel is obtained by hot forging at a hot forging strain rate of 15 min and then slicing along a direction perpendicular to the central axis of the copper rod.

[0038] Examples 3-13 The differences between Examples 3-13 and Example 2 are as follows: In step S1 of Example 3, the acceleration of the acoustic resonance treatment is 30g; In step S1 of Example 4, the acceleration of the acoustic resonance treatment is 40g; In step S1 of Example 5, the acceleration of the acoustic resonance treatment is 50g; In step S1 of Example 6, the acceleration of the acoustic resonance treatment is 70g; In step S1 of Example 7, the acceleration of the acoustic resonance treatment is 80g; In step S1 of Example 8, the acceleration of the acoustic resonance treatment is 90g; In step S1 of Example 9, the acoustic resonance treatment time is 15 minutes; In step S1 of Example 10, the acoustic resonance treatment time is 60 minutes; In step S1 of Example 11, the acoustic resonance treatment time is 75 minutes; In step S1 of Example 12, the acoustic resonance treatment time is 90 minutes; In step S1 of Example 13, the acoustic resonance treatment time is 105 min.

[0039] Comparative Example 1 The difference between this comparative example and Example 2 is that step S1 of this comparative example is as follows: Yttrium oxide powder and copper powder are mixed at a mass ratio of 0.05:1 to obtain a mixture. The mixture and zirconium balls are placed in a ball mill at a mass ratio of 3:1. The zirconium balls are 3 mm in diameter. The mixture is ball-milled at 300 rpm for 100 hours in an argon atmosphere to obtain a composite powder.

[0040] In the implementation of Embodiment 2 and Comparative Example 1 above, the morphology of the composite powder obtained in step S1 was observed using a scanning electron microscope, such as... Figures 1-2 As shown.

[0041] To verify the performance of the copper-based composite resistance seam welding wheel described in this application, the coatings in the copper-based composite resistance seam welding wheels prepared in each embodiment and comparative example were subjected to the following performance tests. The test results are shown in Tables 1 and 2, and the test methods are as follows: (1) Vickers hardness: The Vickers hardness test shall be performed in accordance with the standard GB / T 4340.1-2024; (2) Softening temperature: Tested according to standard GB / T 33370-2016; (3) Relative conductivity: The conductivity was tested in accordance with the standard GB / T 32791-2016 and the relative conductivity was calculated.

[0042] Table 1 Table 2 As can be seen from Examples 1-13 and Comparative Example 1, compared with the existing ball milling method, the acoustic resonance treatment of the mixture of copper powder and yttrium oxide powder in the embodiments of this application can better preserve the morphology of the original powder, improve the density of the coating, and improve the coating's resistance to high-temperature softening, electrical conductivity, and wear resistance. The measured Vickers hardness is not less than 133.3, the softening temperature is not less than 857℃, and the relative conductivity is not less than 79.3%. When the acoustic resonance acceleration is 60-70g and the time is 45-60min, the overall performance of the prepared copper-based composite resistance seam welding wheel is better.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A method for preparing a copper-based composite resistance seam welding wheel, characterized in that, Includes the following steps: S1. After mixing copper powder and yttrium oxide powder, a mixture is obtained. The mixture is then subjected to acoustic resonance treatment to obtain a composite powder. S2. Perform surface pretreatment on the rotating surface of the copper rod; S3. The composite powder obtained in step S1 is deposited on the rotating surface of the copper rod after step S2 by cold spraying to form a coating and obtain the welding wheel blank. S4. The welding wheel blank obtained in step S3 is annealed and then hot-forged into shape, and then sliced ​​to obtain the copper-based composite resistance seam welding wheel.

2. The method for preparing the copper-based composite resistance seam welding wheel as described in claim 1, characterized in that, In step S1, the mass ratio of the yttrium oxide powder to the copper powder is (0.01~0.1):

1.

3. The method for preparing the copper-based composite resistance seam welding wheel as described in claim 1, characterized in that, In step S1, the acoustic resonance treatment is performed in an inert atmosphere, which includes at least one of argon, nitrogen, and helium. The acceleration of the acoustic resonance treatment is 30-90g, and the duration of the acoustic resonance treatment is 15-105min.

4. The method for preparing the copper-based composite resistance seam welding wheel as described in claim 1, characterized in that, In step S2, the diameter of the copper rod is not less than 50 mm.

5. The method for preparing the copper-based composite resistance seam welding wheel as described in claim 1, characterized in that, In step S3, the working gas of the cold spraying process is compressed air, the carrier gas temperature of the cold spraying process is 400~700℃, the carrier gas pressure of the cold spraying process is 3~5MPa, the powder feeding rate of the cold spraying process is 20~100g / min, and the spraying distance of the cold spraying process is 10~20mm.

6. The method for preparing the copper-based composite resistance seam welding wheel as described in claim 1, characterized in that, In step S3, the thickness of the coating is 20~50mm.

7. The method for preparing the copper-based composite resistance seam welding wheel as described in claim 1, characterized in that, During the cold spraying process, the copper rod is rotated around its central axis at a speed of 20-100 rpm.

8. The method for preparing the copper-based composite resistance seam welding wheel as described in claim 1, characterized in that, In step S4, the annealing temperature is 300~600℃, and the annealing time is 2~4h.

9. The method for preparing the copper-based composite resistance seam welding wheel as described in claim 1, characterized in that, In step S4, the hot forging temperature is 500~800℃, and the strain rate of the hot forging is 1~10s. -1 .

10. The method for preparing the copper-based composite resistance seam welding wheel as described in claim 1, characterized in that, In the copper-based composite resistance seam welding wheel, the Vickers hardness of the coating is not less than 140 HV. 500 The softening temperature of the coating is not less than 900℃, and the relative conductivity of the coating is not less than 85% IACS.

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