Brazing process and application of copper alloy-stainless steel composite structure

Abstract

The application discloses a brazing process and application of a copper alloy-stainless steel composite structure and comprises the following steps: S1, performing sand blasting treatment on surfaces of copper alloy and stainless steel base materials to be welded; S2, preparing a uniform and dense corrosion barrier layer on the surface of the copper alloy base material through high-pressure cold spraying; the corrosion barrier layer comprises Ti and Al2O3; S3, placing a BAg20CuZn filler metal made into a welding ring between the copper alloy and the stainless steel base material provided with the corrosion barrier layer, and performing induction heating welding under argon protection; in the cold spraying process, high-pressure gas generates a high-speed airflow carrying Ti and Al2O3 powder particles, the particles are accelerated, and then impact the surface of the copper alloy in a complete solid state, and gradually deposit to form a coating. According to the application, the uniform and dense corrosion barrier layer is arranged between the surface of the copper alloy part and the filler metal through cold spraying, so that galvanic corrosion is effectively inhibited, and meanwhile, good welding performance is maintained.

Description

Technical Field

[0001] This invention relates to the field of brazing technology, and in particular to a brazing process and application for copper alloy-stainless steel composite structural components. Background Technology

[0002] Brazing of copper alloys and stainless steel is frequently used in the pipe connections of household appliances. When copper alloys are welded to connectors, under the action of corrosive media, a spontaneous cell is formed due to the potential difference between the electrodes of the metals. The metal with the lower electrode potential acts as the anode and dissolves, resulting in severe galvanic corrosion that accelerates the corrosion of the anode, i.e., copper, thereby damaging the equipment or materials.

[0003] Galvanic corrosion requires the following conditions to occur: a. a corrosive medium, such as NaCl, acidic media, alkaline media, etc.; b. metals or non-metals in the same medium; c. metals or non-metals coupled; d. the potential difference between the coupled metals is greater than 50mV. Factors affecting galvanic corrosion mainly include the magnitude of the potential difference between metals, ambient temperature, solution ion concentration, and the ratio of anode to cathode area between metals. The potential difference determines the ease with which galvanic corrosion occurs between metals. The greater the potential difference between the galvanic pairs, the higher-potential metal acts as the anode, protecting the cathode and accelerating anodic dissolution. Due to the potential difference between copper alloys and stainless steel, after coupling in a corrosive solution, the copper alloy acts as the anode and dissolves, thus protecting the cathode. Existing technologies for inhibiting metal corrosion at welded locations on pipe fittings often employ inventive concepts similar to those disclosed in utility model CN2022227330289, directly spraying a corrosion-resistant coating onto the metal pipe surface. This corrosion-resistant coating is made of polymer materials such as polyethylene copolymers, limiting the use of welding processes. Summary of the Invention

[0004] The purpose of this invention is to provide a brazing process for copper alloy-stainless steel composite structural components. This invention utilizes cold spraying to create a uniform and dense corrosion barrier layer between the copper alloy component surface and the brazing filler metal, effectively inhibiting galvanic corrosion while maintaining good welding performance. 。

[0005] To solve this technical problem, the technical solution of the present invention is: a brazing process for copper alloy-stainless steel composite structural components, comprising the following steps:

[0006] S1. Sandblasting treatment of the surface of the copper alloy and stainless steel base materials to be welded;

[0007] S2. A uniform and dense corrosion barrier layer is prepared on the surface of the copper alloy base material by high-pressure cold spraying.

[0008] The corrosion barrier layer comprises Ti and Al2O3 particles;

[0009] The process parameters for high-pressure cold spraying are as follows:

[0010] The air pressure at the spray gun inlet is 2.5 MPa to 3.0 MPa, and the temperature is 450℃ to 550℃.

[0011] S3. A welding ring made of BAg20CuZn brazing filler metal is placed between a copper alloy and a stainless steel base material with a corrosion barrier layer, and induction heating is performed under argon protection.

[0012] During the brazing process, Ti forms a Ti-Cu solid solution phase with the copper alloy base material and Cu in the BAg20CuZn brazing filler metal.

[0013] Preferably, in S1, the sandblasting process involves using a sandblasting machine to spray white corundum particles to remove the surface oxide film and dirt; after sandblasting, a high-pressure air gun is used to blow away the surface loose sand for later use. This invention effectively removes dirt and oxide film from the surface of copper alloys, facilitating the formation of a uniform and dense corrosion barrier layer.

[0014] Preferably, the total mass of the Ti-Al2O3 mixed powder forming the corrosion barrier layer is 100 parts, of which 70 to 75 parts are Ti powder and the remainder is Al2O3 powder. This invention effectively ensures that the mass ratio of Al2O3 particles in the coating is not less than 5% by adjusting the mass ratio of Al2O3 and Ti in conjunction with the cold spraying process parameters. Simultaneously, the Al2O3 particles play a compacting role in the sprayed coating, ensuring the formation of the corrosion barrier layer.

[0015] The preferred method for mixing Ti-Al2O3 mixed powder to form a corrosion barrier layer includes the following steps:

[0016] S21. Add Ti powder and Al2O3 powder to a planetary high-energy ball mill according to the mass fractions and grinding balls, with a ball-to-material ratio of 25:1.

[0017] S22. Seal the tank, introduce liquid nitrogen for protection, and then perform low-temperature rapid grinding.

[0018] S23, Take the powder;

[0019] After ball milling is complete, close the liquid nitrogen valve and wait for the temperature in the tank to rise naturally to room temperature. Then, open the sealed lid and remove the grinding balls and powder.

[0020] S24. Sieving powder;

[0021] The powder was dried in a vacuum oven and then sieved using a 400-mesh sieve.

[0022] S25. After taking a sample of the sieved fine powder, vacuum seal it for later use.

[0023] This invention employs a low-temperature rapid mixing method, which effectively ensures the uniform dispersion of Al2O3 particles and Ti particles, while reducing the oxidation of metal particles and ensuring that the corrosion barrier layer is stably connected to the copper alloy surface.

[0024] The preferred process parameters for S22 low-temperature rapid grinding are as follows:

[0025] After liquid nitrogen is introduced, the temperature of the material drops to -180℃ to -195℃. Then, start the ball mill with a ball mill speed of 150r / min to 180r / min and a ball milling time of 8min to 12min.

[0026] Preferably, the thickness of the corrosion barrier layer is between 50 micrometers and 100 micrometers. The corrosion barrier layer obtained by this invention needs to maintain a certain thickness, taking into account both density and uniformity, to ensure reliable welding with stainless steel.

[0027] The preferred process parameters for S3 induction heating welding are as follows:

[0028] Heat at 750℃ to 800℃ for 30 to 60 seconds.

[0029] Preferably, the BAg20CuZn solder comprises the following substances by mass fraction:

[0030]

[0031] This invention uses silver-containing brazing filler metal. The copper in the filler metal forms a solid solution phase with the Ti in the corrosion barrier layer to ensure the mechanical properties of the brazing. At the same time, the corrosion barrier layer inhibits galvanic corrosion. This effectively improves the connection strength and sealing characteristics of pipes used in household appliances or automotive heat exchangers.

[0032] Another objective of this invention is to provide a copper alloy-stainless steel composite structural component. This invention utilizes cold spraying to create a uniform and dense corrosion barrier layer between the surface of the copper alloy component and the brazing filler metal, effectively inhibiting galvanic corrosion while maintaining good weldability and sealing performance.

[0033] To solve this technical problem, the technical solution of the present invention is: a copper alloy-stainless steel composite structural component made by the brazing process proposed in the present invention, comprising a copper alloy component and a stainless steel component, wherein a corrosion barrier layer composed of a mixture of Al2O3 and Ti is high-pressure cold-sprayed onto the surface of the copper alloy component and a brazing filler metal layer for brazing the corrosion barrier layer and the stainless steel component are further included between the copper alloy component and the stainless steel component.

[0034] The present invention applies the copper alloy-stainless steel composite structural component to the connection of interconnected pipelines in household appliances and automotive heat exchangers. The household appliances include one of the following: air conditioner, refrigerator, vacuum cleaner, air purifier, humidifier and washing machine.

[0035] By adopting the above technical solution, the beneficial effects of the present invention are:

[0036] This invention involves cold-spraying a uniform and dense corrosion barrier layer onto the surface of a copper alloy to be welded. The corrosion barrier layer comprises Ti and Al2O3 particles, both with resistivity higher than that of the copper alloy. Due to the impact of the cold spraying process, a small portion of the hard Al2O3 particles and Ti particles are embedded into the copper alloy surface, effectively anchoring the lower-hardness Ti particles to the surface. The remaining majority of the Al2O3 particles, during high-pressure spraying, impact the already formed coating, compacting it and increasing its density before leaving the surface. A small amount of Al2O3 particles participate in the corrosion barrier layer, ensuring its strong bond during the cold spraying process. Furthermore, the non-conductive nature of the Al2O3 particles, combined with the Ti particles, contributes to the corrosion barrier layer's resistance. The low corrosion current suppresses galvanic corrosion. Furthermore, the corrosion barrier layer formed on the copper alloy surface, where Ti has a relatively low thermal conductivity and Al2O3 particles are also poor thermal conductors (as ceramics), provides thermal insulation protection for the copper alloy during welding. This reduces the temperature on the copper alloy side, decreases deformation, lowers weld stress, and reduces the likelihood of cracking. Ti, located between the copper alloy and the brazing layer, forms a Ti-Cu solid solution phase with Cu in both the copper alloy and the brazing layer, effectively inhibiting the penetration of liquid copper and copper alloy into the steel. This improves the welding strength of the resulting composite structure from the perspective of reducing cracking.

[0037] This invention utilizes the inherent density of the corrosion barrier layer and its strong bond with the copper alloy. Further, it combines brazing to transform the brazing of the copper alloy and stainless steel into welding of the corrosion barrier layer and stainless steel. Induction heating welding is performed under argon protection, with the BAg20CuZn brazing filler metal forming a weld layer between the corrosion barrier layer and the steel base material. The Al2O3 and Ti components of the corrosion barrier layer are not only stably bonded to the copper alloy, but during brazing, Ti forms a Ti-Cu solid solution phase with the copper alloy and Cu in the BAg20CuZn brazing filler metal. Compared to the simple dispersion of components in conventional brazing, this invention effectively forms solid solutions with the copper alloy and the brazing layer through the corrosion barrier layer, resulting in a dense interlayer interface. This further reduces the possibility of contact with the corrosive medium during galvanic corrosion, and the high resistance of the corrosion barrier layer further reduces the formation of galvanic corrosion.

[0038] Therefore, the brazing process of the copper alloy-stainless steel composite component proposed in this invention utilizes Ti and Al2O3 to increase the resistance of the corrosion barrier layer, reduce the corrosion current, and inhibit galvanic corrosion, while ensuring the weldability of the composite structure. Thus, the composite structure obtained by this invention is applied to the connecting pipes of household appliances and automotive heat exchangers. Since the connecting pipes of household appliances and automotive heat exchangers are often used in relatively humid environments or with condensation on their surfaces, galvanic corrosion is easily formed. The copper alloy-stainless steel composite structure obtained by the brazing process proposed in this invention effectively inhibits galvanic corrosion, while maintaining a stable connection structure, which is beneficial for the long-term use of the composite structure. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the brazing structure of a copper alloy-stainless steel composite structural component according to the present invention;

[0040] Figure 2 This is a schematic diagram of corrosion current testing for a copper alloy-stainless steel galvanometer pair with a corrosion barrier layer.

[0041] Figure 3 This is a schematic diagram of corrosion current testing for a copper alloy-stainless steel galvanometer pair without a corrosion barrier coating.

[0042] In the picture:

[0043] 1. Copper alloy component; 2. Corrosion barrier layer; 3. Brazing layer; 4. Stainless steel component. Detailed Implementation

[0044] To further explain the technical solution of the present invention, the present invention will be described in detail below through specific embodiments.

[0045] Example 1

[0046] This embodiment discloses a brazing process for a copper alloy-stainless steel composite structure, including the following steps:

[0047] S1. Sandblasting treatment of the surface of the copper alloy and stainless steel base materials to be welded;

[0048] S2. A uniform and dense corrosion barrier layer is prepared on the surface of the copper alloy base material by high-pressure cold spraying.

[0049] The corrosion barrier layer comprises Ti and Al2O3 particles to improve electrical resistance;

[0050] The process parameters for high-pressure cold spraying and the thickness of the corrosion barrier layer are shown in Table 1.

[0051] S3. A welding ring made of BAg20CuZn brazing filler metal is placed between a copper alloy and a stainless steel base material with a corrosion barrier layer, and induction heating is performed under argon protection.

[0052] The process parameters for S3 induction heating welding are shown in Table 1.

[0053] During the brazing process, Ti forms a Ti-Cu solid solution phase with the copper base material and Cu in the BAg20CuZn brazing filler metal.

[0054] In this embodiment, the sandblasting process in S1 involves using a sandblasting machine to spray white corundum abrasive particles to remove the surface oxide film and dirt; after sandblasting, a high-pressure air gun is used to blow away the surface loose sand for later use.

[0055] In this embodiment, the total mass of the Ti-Al2O3 mixed powder forming the corrosion barrier layer is calculated as 100 parts, and the amounts of Ti powder and Al2O3 powder are shown in Table 1.

[0056] The method for mixing Ti-Al2O3 mixed powder to form a corrosion barrier layer includes the following steps:

[0057] S21. Add Al2O3 powder and Ti powder to a planetary high-energy ball mill according to the mass fractions and grinding balls, with a ball-to-material ratio of 25:1.

[0058] S22. Seal the tank, introduce liquid nitrogen for protection, and then perform low-temperature rapid grinding.

[0059] The process parameters for S22 low-temperature rapid grinding are shown in Table 1.

[0060] S23, Take the powder;

[0061] After ball milling is complete, close the liquid nitrogen valve and wait for the temperature in the tank to rise naturally to room temperature. Then, open the sealed lid and remove the grinding balls and powder.

[0062] S24. Sieving powder;

[0063] The powder was dried in a vacuum oven and then sieved using a 400-mesh sieve.

[0064] S25. After taking a sample of the sieved fine powder, vacuum seal it for later use.

[0065] The BAg20CuZn solder described in this embodiment is shown in Table 2 according to its mass fraction.

[0066] The copper alloy-stainless steel composite structural component obtained in this embodiment, such as Figure 1 As shown, it includes a copper alloy part 1 and a stainless steel part 4. Between the copper alloy part 1 and the stainless steel part 4, there is also a corrosion barrier layer 2 composed of Al2O3 and Ti, which is cold-sprayed on the surface of the copper alloy part 1 under high pressure, and a brazing filler layer 3 for brazing the corrosion barrier layer 2 and the stainless steel part 4; wherein the Al2O3 particles impact and fix the Ti particles to the copper alloy surface during the cold spraying process.

[0067] In this embodiment, the stainless steel part is 1Cr18Ni9Ti with a wall thickness of 3mm, and the copper alloy tube is T2 with a wall thickness of 3mm. The two are welded together at the lap joint.

[0068] The copper alloy-stainless steel composite structural component prepared in this embodiment is applied to the connection of interconnected pipelines in household appliances, including one of air conditioners, refrigerators, vacuum cleaners, air purifiers, humidifiers, and washing machines.

[0069] Example 2

[0070] The differences in brazing process parameters between this embodiment and Embodiment 1 are detailed in Table 1, and the composition and amount of BAg20CuZn brazing filler metal are detailed in Table 2.

[0071] Example 3

[0072] The differences in brazing process parameters between this embodiment and Embodiment 1 are detailed in Table 1, and the composition and amount of BAg20CuZn brazing filler metal are detailed in Table 2.

[0073] Example 4

[0074] The differences in brazing process parameters between this embodiment and Embodiment 1 are detailed in Table 1, and the composition and amount of BAg20CuZn brazing filler metal are detailed in Table 2.

[0075] Comparative Example

[0076] This comparative example discloses a brazing process for a copper alloy-stainless steel composite structural component, including the following steps:

[0077] S1. Sandblasting treatment of the surface of the copper alloy and stainless steel base materials to be welded; in this embodiment, the sandblasting treatment in S1 is to spray white corundum abrasive particles with a sandblasting machine to remove the surface oxide film and dirt; after sandblasting treatment, use a high-pressure air gun to blow away the surface loose sand for later use.

[0078] S2. A brazing ring made of BAg20CuZn brazing filler metal is placed between the copper alloy and the stainless steel base material, and induction heating welding is performed under argon protection to obtain a composite structure of copper alloy and stainless steel.

[0079] The process parameters for S2 induction heating welding are as follows:

[0080] The heating temperature is 750℃ and the heating time is 50s.

[0081] The BAg20CuZn solder used in this embodiment is the same as that in Example 2 in terms of mass fraction.

[0082] Table 1. Brazing process parameters in Examples 1 to 4

[0083]

[0084]

[0085] Table 2 shows the composition and amount (by mass percentage) of the BAg20CuZn solder in Examples 1 to 4.

[0086] project Example 1 Example 2 Example 3 Example 4 Ag 17％ 20％ 18％ 20％ Cu 43％ 44％ 45％ 44％ Zn 36％ 34％ 35％ 34％ In 2％ 1％ 1％ 1％ Sn 2％ 1％ 1％ 1％

[0087] The porosity of the corrosion barrier layer in Examples 1 to 4 was determined, and the mechanical properties of the welded joints of the copper alloy-stainless steel composite structures obtained in Examples 1 to 4 and the comparative example were tested. The specific test data are shown in Table 3.

[0088] Table 3 Performance indicators of copper alloy-stainless steel composite structural components obtained in Examples 1 to 4 and comparative examples.

[0089]

[0090]

[0091] The porosity test method is as follows:

[0092] The porosity of the coating was measured using the DT2000 image analysis software based on the grayscale method at 200×.

[0093] The mechanical property test of the welded joint was carried out in accordance with GB2651-89 "Tension Test Method for Welded Joints". Tensile specimens were cut from the welded joint along the direction perpendicular to the weld, ensuring that the weld was in the middle of the specimen, and the tensile speed was 1 mm / min.

[0094] Joint sealing test method: hydraulic test at 10MPa, air pressure at 5MPa for 5 minutes and then air tightness test.

[0095] The method for testing corrosion current is as follows:

[0096] Sample: Prepare a T2 copper alloy round bar with a Ti-Al2O3 coating on the end face, with a diameter of 15mm.

[0097] Electrode wire installation: Solder fine copper enameled wire to a distance of 5mm from the copper alloy end face.

[0098] Encapsulation: After covering the sample with a 6mm diameter cover plate, use insulating coating to encapsulate it. After encapsulation, check that the electrode wires are properly encapsulated. Remove the cover plate to expose the circular area of ​​the coating end face.

[0099] Connect the electrode wires to the stainless steel as described above, and then encapsulate it.

[0100] Use deionized water to prepare a 3.5% sodium chloride solution; test temperature: 35℃±2℃; test period: 15-45 days; place a 1L beaker containing about 800mL of sample solution in a constant temperature water bath and heat to the test temperature.

[0101] like Figure 2 and Figure 3 As shown, the encapsulated copper alloy and stainless steel samples were placed side by side with their exposed surfaces facing each other, and the distance between them was 30 mm.

[0102] The galvanic corrosion voltage and current versus time curves were measured and recorded using an electrochemical workstation. Galvanic corrosion was considered to have occurred when the galvanic potential difference exceeded 50 mV. Galvanic current density Is = maximum galvanic current / test area.

[0103] As shown in Tables 1 to 3, the thickness of the corrosion barrier layer in Example 3 is the largest compared to Examples 1 and 2, and the Al2O3 particle content is relatively lower than that in Examples 1 and 2. This is not conducive to the bonding between the corrosion barrier layer and the copper alloy, nor is it conducive to the density of the layer structure. The density and welding strength of Examples 3 and 4 are lower than those of Examples 1 and 2, respectively. Even though the corrosion barrier layer in Example 3 has the largest thickness, its film density is poor, and the bonding with the copper alloy is not sufficiently solidified. Therefore, the bonding between the corrosion barrier layer and the copper alloy is limited, and the mechanical properties of the brazed layer are worse than those of Examples 1 and 2. The transverse tensile strength of the corresponding composite structure is lower than that of Examples 1 and 2. The main difference between Example 2 and Example 4 lies in the difference in Al2O3 powder used in the cold spraying process. In Example 4, the amount of Al2O3 powder used is less, and the porosity of the corrosion barrier layer is higher. On the one hand, the uniformity and density of the solid solution phase formed by Ti with copper alloy and Cu in the brazing filler layer are correspondingly reduced. On the other hand, the reduction of Al2O3 in the corrosion barrier layer is not conducive to the improvement of the corrosion barrier layer resistance. Moreover, the electrolyte, which has a positive effect on corrosion, can easily enter the corrosion barrier layer with high porosity through the pores, reducing the protective effect of the barrier layer and causing the corrosion current density to increase. Therefore, the performance of the composite structure obtained in Example 4 is lower than that of the composite structure obtained in Example 2.

[0104] The standard electrode potential of copper is +0.337V, while the electrode potential of different grades of stainless steel varies from +0.5V to +1.8V. A significant potential difference often exists between these two metals, making them prone to galvanic corrosion. This invention involves cold-spraying a uniform and dense corrosion barrier layer onto the surface of the copper alloy to be welded. This corrosion barrier layer comprises Ti and Al2O3 particles, both with higher resistivity than the copper alloy. Due to the impact of cold spraying, a small portion of the hard Al2O3 particles and Ti particles embed together into the copper alloy surface, while the softer Ti particles are anchored to the surface. The remaining majority of the Al2O3 particles, during high-pressure spraying, impact the already formed coating, compacting it and increasing its density before leaving the surface. A small amount of Al2O3 particles participate in the corrosion barrier layer during cold spraying. During the coating process, a strong bond is ensured to the corrosion barrier layer. Furthermore, the non-conductive Al2O3 particles, together with Ti, reduce the corrosion current in the corrosion barrier layer, thereby inhibiting galvanic corrosion. On the other hand, the corrosion barrier layer formed on the copper alloy surface, where Ti has a relatively low thermal conductivity and Al2O3 particles, being ceramic, are also poor conductors of heat, provides thermal insulation protection for the copper alloy during welding. This reduces the temperature on the copper alloy side, decreases deformation, lowers weld stress, and reduces the likelihood of cracking. Ti, positioned between the copper alloy and the brazing layer, forms Ti-Cu, effectively inhibiting the penetration of liquid copper and copper alloy into the steel, thus improving the welding strength of the resulting composite structure from the perspective of reducing cracking.

[0105] This invention utilizes the inherent density of the corrosion barrier layer and its strong bond with the copper alloy, further enhanced by brazing, to transform the brazing of the copper alloy and stainless steel into welding of the corrosion barrier layer and stainless steel. Induction heating welding is performed under argon protection, with the BAg20CuZn brazing filler metal forming a weld layer between the corrosion barrier layer and the steel base material. The Al2O3 and Ti components of the corrosion barrier layer are stably bonded to the copper alloy. During brazing, Ti forms a Ti-Cu solid solution phase with the copper alloy and Cu in the BAg20CuZn brazing filler metal. Compared to the simple dispersion of components in conventional brazing, this invention effectively forms solid solutions with both the copper alloy and the brazing layer through the corrosion barrier layer, resulting in a dense interlayer interface. This further reduces the possibility of contact with the corrosive medium during galvanic corrosion. The high resistance of the corrosion barrier layer further reduces the formation of galvanic corrosion. Therefore, the brazing process for copper alloy-stainless steel composite parts proposed in this invention utilizes Ti and Al2O3 to increase the resistance of the corrosion barrier layer, reducing corrosion current and inhibiting galvanic corrosion, while simultaneously ensuring the weldability of the composite structure.

[0106] Because the connecting pipes of household appliances and automotive heat exchangers are often used in relatively humid environments or with condensation on their surfaces, they are prone to galvanic corrosion. The copper alloy-stainless steel composite structural component manufactured using the brazing process proposed in this invention effectively inhibits galvanic corrosion, while also providing a stable connection structure, which is beneficial for the long-term use of the composite component. Therefore, the composite structural component obtained by this invention is suitable for use in the connecting pipe sections of household appliances and automotive heat exchangers, and can replace all-copper components used in household appliances and automotive heat exchangers with steel alloy-stainless steel composite structural components.

Claims

1. A brazing process for a copper alloy-stainless steel composite structural component, characterized in that: Includes the following steps: S1. Sandblasting treatment of the surface of the copper alloy and stainless steel base materials to be welded; S2. A uniform and dense corrosion barrier layer is prepared on the surface of the copper alloy base material by high-pressure cold spraying. The corrosion barrier layer comprises Ti and Al2O3 particles; The process parameters for high-pressure cold spraying are as follows: The air pressure at the spray gun inlet is 2.5 MPa to 3.0 MPa, and the temperature is 450℃ to 550℃. S3. A welding ring made of BAg20CuZn brazing filler metal is placed between a copper alloy and a stainless steel base material with a corrosion barrier layer, and induction heating is performed under argon protection. During the brazing process, Ti forms a Ti-Cu solid solution phase with the copper alloy base material and Cu in the BAg20CuZn brazing filler metal.

2. The brazing process for a copper alloy-stainless steel composite structural component as described in claim 1, characterized in that: In S1, the sandblasting process involves using a sandblasting machine to spray white corundum abrasive particles to remove the surface oxide film and dirt; after sandblasting, a high-pressure air gun is used to blow away the surface loose sand for later use.

3. The brazing process for a copper alloy-stainless steel composite structural component as described in claim 1, characterized in that: The total mass of the Ti-Al2O3 mixed powder forming the corrosion barrier layer is 100 parts, of which 70 to 75 parts are Ti powder and the remainder is Al2O3 powder.

4. The brazing process for a copper alloy-stainless steel composite structural component as described in claim 3, characterized in that: The method for mixing Ti-Al2O3 mixed powder to form a corrosion barrier layer includes the following steps: S21. Add Ti powder and Al2O3 powder to a planetary high-energy ball mill according to the mass fractions and grinding balls, with a ball-to-material ratio of 25:

1. S22. Seal the tank, introduce liquid nitrogen for protection, and then perform low-temperature rapid grinding. S23, Take the powder; After ball milling is complete, close the liquid nitrogen valve and wait for the temperature in the tank to rise naturally to room temperature. Then, open the sealed lid and remove the grinding balls and powder. S24. Sieving powder; The powder was dried in a vacuum oven and then sieved using a 400-mesh sieve. S25. After taking a sample of the sieved fine powder, vacuum seal it for later use.

5. The brazing process for a copper alloy-stainless steel composite structural component as described in claim 4, characterized in that: The process parameters for S22 low-temperature rapid grinding are as follows: After liquid nitrogen is introduced, the temperature of the material drops to -180℃ to -195℃. Then, start the ball mill with a ball mill speed of 150r / min to 180r / min and a ball milling time of 8min to 12min.

6. The brazing process for a copper alloy-stainless steel composite structural component as described in any one of claims 1 to 5, characterized in that: The thickness of the corrosion barrier layer is 50 micrometers to 100 micrometers.

7. The brazing process for a copper alloy-stainless steel composite structural component as described in any one of claims 1 to 5, characterized in that: The process parameters for S3 induction heating welding are as follows: The heating temperature is 750℃ to 800℃, and the heating time is 30s to 60s.

8. The brazing process for a copper alloy-stainless steel composite structural component as described in claim 1, characterized in that: The BAg20CuZn solder comprises the following substances by mass fraction:

9. A copper alloy-stainless steel composite structural component manufactured by the brazing process according to any one of claims 1 to 8, characterized in that: It includes copper alloy parts and stainless steel parts, and between the copper alloy parts and stainless steel parts, there is a corrosion barrier layer made of a mixture of Ti and Al2O3 that is high pressure cold sprayed on the surface of the copper alloy parts, and a brazing filler layer for brazing the corrosion barrier layer and the stainless steel parts.

10. The copper alloy-stainless steel composite structural component of claim 9 is used to connect interconnected pipelines in household appliances or automotive heat exchangers, wherein the household appliances include one of air conditioners, refrigerators, vacuum cleaners, air purifiers, humidifiers, and washing machines.

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