Copper-steel bimetal piece with complex inner runner and preparation method of copper-steel bimetal piece

Abstract

The invention relates to the technical field of dissimilar metal connection, in particular to a copper-steel bimetal piece with a complex inner runner and a preparation method thereof.The preparation method comprises the steps that a cooling runner is preprocessed through a copper alloy blank, and a primary copper alloy workpiece is obtained; the primary copper alloy part is cleaned, and a secondary copper alloy part is obtained; the stainless steel blank is subjected to surface treatment and cleaning, and a stainless steel workpiece is obtained; the secondary copper alloy workpiece and the stainless steel workpiece are assembled and then are arranged in a sheath; the sheath is heated and vacuumized and then is sealed and welded; carrying out hot isostatic pressing treatment on the sealed and welded sheath to obtain an intermediate part; and the steel ladle sleeve outside the middle part is removed, and the copper-steel bimetal part is obtained. According to the method, the phenomena of generation of brittle intermetallic compounds on the interface and grain coarsening are avoided, the connection strength is remarkably improved, interface metallurgical bonding and high-precision shape control of a cooling runner are synchronously completed in a single process, and the geometric precision of the copper-steel bimetal part is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of dissimilar metal joining, and particularly relates to a copper-steel bimetallic part with complex internal flow channels and a preparation method thereof. Background Art

[0002] In high-end equipment fields such as nuclear energy, aerospace, high-energy lasers, and mechanical equipment, copper-stainless steel composite components, relying on the synergistic characteristics of their high thermal conductivity and high strength, have become the core materials for key components (such as nuclear reactor heat exchangers, aerospace engine combustion chambers) under extreme working conditions. Such components need to achieve long-term stable service in high-temperature, high-pressure, and strong thermal shock environments. Traditional single materials or non-integrated designs are difficult to meet the multi-functional collaborative requirements of "efficient heat dissipation - mechanical load-bearing - reliable sealing" due to the problem of functional fragmentation, which promotes the integrated manufacturing technology of dissimilar metal interfaces and internal cavity structures to become the forefront research direction in the industry.

[0003] Currently, the dissimilar metal joining and complex structure forming technologies still face multiple challenges. The brazing process relies on low-melting-point brazing materials to achieve the interface bonding between copper and stainless steel. However, the physical property differences between the brazing material and the substrate lead to the formation of brittle phases at the interface, significantly weakening the joint strength and thermal shock resistance. Moreover, the residue of the brazing material is likely to cause electrochemical corrosion, affecting the durability of the component in corrosive media. Although 3D printing technology can directly form complex embedded flow channels, during the printing process of dissimilar metals, interface delamination, residual stress concentration, and pore defects caused by differences in thermophysical properties (such as mismatch of thermal expansion coefficients and thermal conductivities) lead to a decrease in the fatigue life and sealing performance of the component.

[0004] Aiming at the problems of the generation of brittle phases at the dissimilar metal interface, insufficient joint strength and sealing failure caused by thermal stress mismatch in the existing technologies mentioned above, there is an urgent need to develop a more excellent preparation method to achieve the coordinated control of the metallurgical bonding strength of the heterogeneous interface and the geometric accuracy of the embedded flow channels, providing manufacturing technology support and engineering guarantee for the efficient thermal management, MPa-level mechanical load-bearing, and long-term reliable sealing of extreme environment equipment such as the first wall of nuclear fusion devices and high thrust-to-weight ratio aerospace engine combustion chambers. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned existing technologies, and provide a copper-steel bimetallic part with complex internal flow channels and a preparation method thereof, so as to solve the problems of insufficient joint strength caused by physical property differences at the copper-steel heterogeneous interface and the deterioration of geometric accuracy of the embedded cooling flow channels during multi-process machining.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] The present invention provides a preparation method for a copper-steel bimetallic part with complex internal flow channels, comprising the following steps:

[0008] S1. Preprocess the cooling channels of the copper alloy blank to obtain a primary copper alloy part;

[0009] S2. Clean the primary copper alloy part to obtain a secondary copper alloy part;

[0010] S3. Surface-treat and clean the stainless steel blank to obtain a stainless steel part;

[0011] S4. Assemble the secondary copper alloy part and the stainless steel part and place them in a jacket, then weld the connection of the jacket;

[0012] S5. Heat and evacuate the welded jacket and then seal-weld it;

[0013] S6. Perform hot isostatic pressing on the seal-welded jacket to obtain an intermediate part;

[0014] S7. Remove the jacket outside the intermediate part to obtain the copper-steel bimetallic part.

[0015] Specifically, in S4, before assembling the secondary copper alloy part and the stainless steel part, first coat a nickel layer with a thickness of (5μm - 8μm) ± 0.3μm on the area of the secondary copper alloy part that connects to the stainless steel part.

[0016] Specifically, electrochemically deposit a nickel layer on the secondary copper alloy part. The electroplating solution used is a nickel sulfamate solution, and the electroplating parameters are: current density 2A / dm 2 ~4A / dm 2 , and electroplating time 20min - 40min.

[0017] Specifically, in S4, a graphite paper is attached to the inner wall of the jacket.

[0018] Specifically, in S6, the process of the hot isostatic pressing is: heat up at a heating rate of 5℃ / min - 10℃ / min to 700℃ - 1000℃, increase the pressure to 10MPa - 30MPa as the temperature rises, hold the temperature and pressure for 60min - 240min, and then cool down at a cooling rate of 2℃ / min - 10℃ / min to 100℃ and then take out of the furnace.

[0019] Specifically, in S2, the process of the cleaning treatment is: immerse the primary copper alloy part in an acidic solution for cleaning, then rinse with deionized water and dry;

[0020] In S5, the specific process of surface-treating and cleaning the stainless steel blank is: first polish the inner wall of the stainless steel blank, then clean the surface of the stainless steel blank with gasoline, then clean the surface of the stainless steel blank with acetone, and finally blow-dry the surface of the stainless steel blank with argon.

[0021] Specifically, the acidic solution is a 10 wt% - 15 wt% nitric acid solution, the temperature of the acidic solution is 25°C - 40°C, and the cleaning time in the acidic solution is 3 min - 10 min.

[0022] Specifically, the specific process of S5 is as follows: After evacuating the internal vacuum of the welded jacket to ≤1.0×10 -2 Pa, heat the welded jacket to 350°C - 450°C, keep it warm for 2 h - 4 h, and then perform sealing welding.

[0023] Specifically, the width of the cooling channel is 2 mm - 3 mm, the depth is 6 mm - 8 mm, the center distance between adjacent cooling channels is 2.2 mm - 3.5 mm, and the bottom thickness of the cooling channel is 1.2 mm - 1.5 mm.

[0024] The present invention also provides a copper - steel bimetallic part with complex internal flow channels prepared by the above - mentioned preparation method.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] (1) The present invention uses the hot isostatic pressing process to achieve diffusion bonding of the copper - steel heterogeneous interface. The solid - state diffusion mechanism of hot isostatic pressing does not involve the liquid - phase remelting process, avoiding the formation of brittle intermetallic compounds at the interface and the phenomenon of grain coarsening, significantly improving the bonding strength. Moreover, the method proposed by the present invention synchronously completes the interfacial metallurgical bonding and high - precision shape control of the internal cooling channels in a single process, avoiding the secondary processing links required by traditional processes and ensuring the geometric accuracy of the copper - steel bimetallic part.

[0027] (2) The present invention performs hot isostatic pressing under specific parameters. By uniformly applying pressure and precisely controlling the temperature, it can not only ensure good diffusion bonding of the copper - steel heterogeneous interface but also avoid the collapse or deformation of the internal cooling channels caused by uneven stress distribution, enabling the channels to maintain the original design accuracy and directly meeting the test requirements for the failure pressure of the subsequent copper - steel bimetallic part.

[0028] (3) Before assembling the secondary copper alloy part and the stainless - steel part, the present invention first coats the area where the secondary copper alloy part is connected to the stainless - steel part with a nickel layer. Since the nickel layer serves as a diffusion kinetics buffer medium, it can inhibit the formation of interfacial micro - defects caused by the Kirkendall effect, further improving the bonding strength and tightness of the copper - steel heterogeneous interface, and at the same time ensuring the long - term stability of the cooling channel sealing interface of the copper - steel bimetallic part.

[0029] (4) A graphite paper isolation layer is attached to the inner wall of the sleeve of the present invention to block the diffusion adhesion between the copper-steel bimetallic part and the sleeve material. This design facilitates the subsequent removal of the sleeve material. The copper-steel bimetallic part only needs to be slightly polished to meet the use precision requirements, significantly reducing the processing cost and improving the material utilization rate. Description of the Drawings

[0030] Figure 1 is the process flow chart for the preparation of the present invention;

[0031] Figure 2 is the structural schematic diagram of the copper-steel bimetallic part of the present invention;

[0032] Figure 3 is the morphology diagram of the copper-steel connection interface of the copper-steel bimetallic part prepared in Example 1 of the present invention;

[0033] Figure 4 is the microscopic morphology diagram of the copper-steel connection interface of the copper-steel bimetallic part prepared in Example 2 of the present invention;

[0034] Reference Signs:

[0035] 1. Copper alloy layer; 2. Cooling channel; 3. Stainless steel layer. Detailed Embodiments

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0037] Example 1

[0038] Refer to Figure 1 and Figure 2 , this embodiment provides a preparation method for a CuZr alloy-304 stainless steel bimetallic part with complex internal channels, and the specific process is as follows:

[0039] S1. The CuZr alloy blank is pre-processed by numerical control milling to obtain a primary CuZr alloy part with cooling channels. The surface roughness Ra of the primary CuZr alloy part is ≤1.6 μm. The width of the cooling channels is 2 mm, the depth is 6 mm, the center distance between adjacent cooling channels is 3.5 mm, and the bottom thickness of the cooling channels is 1.5 mm;

[0040] S2. Put the primary CuZr alloy workpiece obtained in S1 into a 10 wt% nitric acid solution, control the temperature of the pickling solution at 40 °C, and the treatment duration at 3 min. Then rinse with deionized water and transfer it to a nitrogen-protected drying oven for drying to obtain a secondary CuZr alloy workpiece;

[0041] S3. First, polish the inner wall of the 304 stainless steel blank using a precision CNC grinding machine, control the surface roughness Ra ≤ 0.4 μm, then remove the oil stain on the surface of the 304 stainless steel blank with gasoline, then clean it with acetone organic solvent, and finally dry it with argon to obtain a 304 stainless steel workpiece;

[0042] S4. In a nickel sulfamate electrolyte (Ni2+ concentration 80 g / L, pH value 4.1, temperature 50 °C), electrochemically deposit a nickel layer with a thickness of 5 μm ± 0.3 μm on the area where the secondary CuZr alloy workpiece is connected to the stainless steel workpiece. After assembling the nickel-plated secondary CuZr alloy workpiece and the 304 stainless steel workpiece, place them in a jacket. During the nickel plating process of the secondary CuZr alloy workpiece, the current density is 2 A / dm 2 , and the electroplating time is 40 min; Since the jacket in this embodiment is split, it is necessary to weld the split joints of the assembled jacket to ensure the sealing of the jacket; In this embodiment, graphite paper is also attached to the inner wall of the jacket;

[0043] S5. After evacuating the internal vacuum of the welded jacket to 1.0×10 -2 Pa, keep the evacuated jacket at 450 °C for 2 h, and then perform sealing welding;

[0044] S6. Perform hot isostatic pressing on the sealed jacket to obtain an intermediate workpiece; The process of the hot isostatic pressing is as follows: heat up to 700 °C at a heating rate of 5 °C / min, increase the pressure to 30 MPa as the temperature rises, keep the temperature and pressure for 240 min, and then cool down to 100 °C at a cooling rate of 2 °C / min and then take it out of the furnace;

[0045] S7. Remove the jacket outside the intermediate workpiece to obtain a CuZr alloy - 304 stainless steel bimetallic part.

[0046] The morphology diagram of the copper - steel connection interface of the CuZr alloy - 304 stainless steel bimetallic part prepared in this embodiment is for reference Figure 3 .

[0047] Example 2

[0048] This embodiment provides a preparation method for a CuCrZr alloy - 304 stainless steel bimetallic part with complex internal flow channels, and the specific process is as follows:

[0049] S1. Preprocess the CuCrZr alloy blank by CNC milling to obtain a primary CuCrZr alloy part with cooling channels. The surface roughness Ra of the primary CuCrZr alloy part is ≤ 1.5 μm. The width of the cooling channels is 2.3 mm, the depth is 8 mm, the center distance between adjacent cooling channels is 2.6 mm, and the bottom thickness of the cooling channels is 1.4 mm.

[0050] S2. Immerse the primary CuCrZr alloy part obtained in S1 into a 12 wt% nitric acid solution, control the temperature of the pickling solution at 30 °C, and the treatment duration at 5 min. Then rinse with deionized water and transfer it to a nitrogen-protected drying oven for drying to obtain a secondary CuCrZr alloy part.

[0051] S3. First, polish the inner wall of the 304 stainless steel blank using a precision CNC grinding machine, control the surface roughness Ra ≤ 0.3 μm. Then remove the oil stain on the surface of the 304 stainless steel blank with gasoline, and then clean it with acetone organic solvent. Finally, dry it with argon to obtain a 304 stainless steel part.

[0052] S4. In a nickel sulfamate electrolyte (Ni2+ concentration 80 g / L, pH value 4.1, temperature 50 °C), electrochemically deposit a nickel layer with a thickness of 6 μm ± 0.3 μm on the area where the secondary CuCrZr alloy part is connected to the stainless steel part. After assembling the nickel-plated secondary CuCrZr alloy part and the 304 stainless steel part, place them in a shroud. During the nickel plating process of the secondary CuCrZr alloy part, the current density is 2.7 A / dm 2 , and the electroplating time is 35 min. Since the shroud in this embodiment is in two parts, it is necessary to weld the split joints of the assembled shroud to ensure the sealing of the shroud. In this embodiment, graphite paper is also attached to the inner wall of the shroud.

[0053] S5. After evacuating the internal vacuum of the welded shroud to 0.8×10 -2 Pa, keep the evacuated shroud at 420 °C for heat preservation for 2.5 h, and then perform sealing welding.

[0054] S6. Perform hot isostatic pressing on the sealed shroud to obtain an intermediate part. The process of the hot isostatic pressing is as follows: heat up at a heating rate of 7 °C / min to 800 °C, increase the pressure to 25 MPa as the temperature rises, keep the temperature and pressure for 180 min, and then cool down at a cooling rate of 5 °C / min to 100 °C and then take it out of the furnace.

[0055] S7. Remove the shroud outside the intermediate part to obtain a CuCrZr alloy-304 stainless steel bimetallic part.

[0056] The micrograph of the copper-steel joint interface of the CuCrZr alloy-304 stainless steel bimetallic part prepared in this example is for reference Figure 4 .

[0057] Example 3

[0058] This example provides a preparation method for a T2 copper-316L stainless steel bimetallic part with complex internal flow channels. The specific process is as follows:

[0059] S1. The T2 copper blank is pre-processed by numerical control milling to obtain a primary T2 copper part with cooling channels. The surface roughness Ra of the primary T2 copper part is ≤1.5 μm. The width of the cooling channel is 3 mm, the depth is 7 mm, the center distance between adjacent cooling channels is 2.2 mm, and the bottom thickness of the cooling channel is 1.3 mm;

[0060] S2. The primary T2 copper part obtained in S1 is put into a 15 wt% nitric acid solution, the temperature of the pickling solution is controlled at 25 °C, and the treatment duration is 10 min. Then it is rinsed with deionized water and transferred to a nitrogen-protected drying oven for drying to obtain a secondary T2 copper part;

[0061] S3. First, the inner wall of the 316L stainless steel blank is polished by a precision numerical control grinding machine to control the surface roughness Ra ≤ 0.3 μm. Then the oil on the surface of the 304 stainless steel blank is removed with gasoline, then it is cleaned with acetone organic solvent, and finally it is dried with argon to obtain a 316L stainless steel part;

[0062] S4. In a nickel sulfamate electrolyte (Ni2+ concentration 80 g / L, pH value 4.1, temperature 50 °C), a nickel layer with a thickness of 7 μm ± 0.3 μm is plated on the area of the secondary T2 copper part that is to be connected to the stainless steel part by electrochemically depositing method. After the nickel-plated secondary T2 copper part and the 316L stainless steel part are assembled, they are placed in a jacket. Among them, during the nickel plating process of the secondary T2 copper part, the current density is 3.5 A / dm 2 , and the electroplating time is 27 min; Since in this example, the jacket is in parts, the split joints of the assembled jacket need to be welded to ensure the tightness of the jacket; In this example, graphite paper is also attached to the inner wall of the jacket;

[0063] S5. After the internal vacuum degree of the welded jacket is pumped to 0.7×10 -2 Pa, the evacuated jacket is kept warm at 380 °C for 3.5 h and then sealed and welded;

[0064] S6. Perform hot isostatic pressing on the sealed jacket to obtain an intermediate workpiece. The process of the hot isostatic pressing is as follows: Heat up at a heating rate of 8 °C / min to 900 °C, increase the pressure to 18 MPa along with the temperature, hold the temperature and pressure for 120 min, and then cool down at a cooling rate of 8 °C / min to 100 °C and then take out of the furnace.

[0065] S7. Remove the jacket outside the intermediate workpiece to obtain a T2 pure copper - 316L stainless steel bimetallic part.

[0066] Example 4

[0067] This example provides a preparation method for a CuZr alloy - 304 stainless steel bimetallic part with complex internal flow channels. The specific process is as follows:

[0068] S1. Pre - process the CuZr alloy blank by numerical control milling to obtain a primary CuZr alloy workpiece with cooling channels. The surface roughness Ra of the primary CuZr alloy workpiece is ≤1.6 μm. The width of the cooling channel is 2.6 mm, the depth is 7 mm, the center distance between adjacent cooling channels is 3 mm, and the bottom thickness of the cooling channel is 1.4 mm.

[0069] S2. Immerse the primary CuZr alloy workpiece obtained in S1 into a 14 wt% nitric acid solution, control the temperature of the pickling solution at 35 °C, and the treatment duration at 7 min. Then rinse with deionized water and transfer it to a nitrogen - protected drying oven for drying to obtain a secondary CuZr alloy workpiece.

[0070] S3. First, polish the inner wall of the 304 stainless steel blank with a precision numerical control grinding machine to control the surface roughness Ra ≤0.4 μm. Then remove the oil stain on the surface of the 304 stainless steel blank with gasoline, then clean it with acetone organic solvent, and finally blow it dry with argon to obtain a 304 stainless steel workpiece.

[0071] S4. In a nickel sulfamate electrolyte (Ni2+ concentration 80 g / L, pH value 4.1, temperature 50 °C), electrochemically deposit an 8 μm ± 0.3 μm nickel layer on the area of the secondary CuZr alloy workpiece connected to the stainless steel workpiece by electro - deposition method. After assembling the nickel - plated secondary CuZr alloy workpiece and the 304 stainless steel workpiece, install them in a jacket. Among them, during the nickel plating process of the secondary CuZr alloy workpiece, the current density is 4 A / dm 2 , and the electroplating time is 20 min. Since in this example, the jacket is in parts, it is necessary to weld the split joints of the assembled jacket to ensure the sealing of the jacket. In this example, graphite paper is also attached to the inner wall of the jacket.

[0072] S5. Pump the internal vacuum of the welded jacket to 0.9×10 -2After Pa, the evacuated jacket is heat-insulated at 350 °C for 4 h, and then sealed by welding;

[0073] S6. Perform hot isostatic pressing on the sealed jacket to obtain an intermediate workpiece; the process of the hot isostatic pressing is as follows: heat up to 1000 °C at a heating rate of 10 °C / min, increase the pressure to 10 MPa as the temperature rises, keep the temperature and pressure for 60 min, and cool down to 100 °C at a cooling rate of 10 °C / min and then take out of the furnace;

[0074] S7. Remove the jacket outside the intermediate workpiece to obtain a CuZr alloy-304 stainless steel bimetallic part.

[0075] In the above embodiments, the jacket is preferably a steel jacket, the wall thickness of the jacket is 3 mm to 10 mm, and the thickness of the graphite paper is 0.1 to 0.5 mm.

[0076] Reference Figure 2 , the copper-steel bimetallic part prepared in the above embodiments includes a hollow copper alloy layer 1, a cooling channel 2 is arranged at intervals along the circumferential direction outside the copper alloy layer 1, a nickel layer is plated on the outer surface of the copper alloy layer 1, and the copper alloy layer 1 is embedded in the stainless steel layer 3.

[0077] Reference Figure 3 and Figure 4 It can be seen that there are no holes and brittle phases generated at the copper-steel connection interface of the copper-steel bimetallic part prepared by the present invention.

[0078] In order to better illustrate the beneficial effects of the present invention, the copper-steel bimetallic parts prepared in the above Examples 1 to 4 are encapsulated, pressurized into the cooling channels of the copper-steel bimetallic parts, a failure pressure test is carried out, and the copper-steel bimetallic parts after the test are dissected and the dimensions are measured to obtain the critical failure pressure and the deformation rate of the copper alloy side along the depth direction of the cooling channel. The test results are shown in Table 1 below:

[0079] Table 1

[0080] Example Breaking pressure / MPa Deformation rate / % 1 102.2 0.11 2 115.7 0.09 3 99.1 0.15 4 103.4 0.10

[0081] It can be seen from the data in Table 1 that the copper-steel bimetallic parts with higher bonding strength and smaller geometric deformation of the cooling channels can be prepared by the preparation method provided by the present invention, which can effectively solve the problems of generation of brittle phases at the interface caused by the physical property differences of dissimilar metals, weakening of the connection strength due to thermal stress mismatch, and geometric distortion and sealing failure of the channels caused by the thermo-mechanical coupling effect in the traditional technology.

[0082] The specific embodiments of the present invention enable those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0083] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A preparation method of a copper-steel bimetallic part with complex internal flow channels, characterized in that, It includes the following steps: S1. Preprocess the cooling channels of the copper alloy blank to obtain a primary copper alloy part; S2. Clean the primary copper alloy part to obtain a secondary copper alloy part; S3. Surface-treat and clean the stainless steel blank to obtain a stainless steel part; S4. Assemble the secondary copper alloy part and the stainless steel part and install them in a jacket, and then weld the connection of the jacket; S5. Heat and evacuate the welded jacket and then perform seal welding; S6. Perform hot isostatic pressing on the sealed jacket to obtain an intermediate part; S7. Remove the jacket outside the intermediate part to obtain the copper-steel bimetal part.

2. The preparation method of the copper-steel bimetallic part with complex internal flow channels according to claim 1, characterized in that, In S4, before assembling the secondary copper alloy part and the stainless steel part, first coat the area connecting the stainless steel part on the secondary copper alloy part with a nickel layer of (5μm - 8μm) ± 0.3μm.

3. The preparation method of the copper-steel bimetallic part with a complex internal flow channel according to claim 2, characterized in that, Electroplating a nickel layer on the secondary copper alloy workpiece by electrochemically depositing method, using nickel sulfamate solution as the electroplating solution, and the electroplating parameters are: current density 2 A / dm 2 ~4 A / dm 2 , and electroplating time 20 min~40 min.

4. The preparation method of the copper-steel bimetallic part with complex internal flow channels according to claim 1, characterized in that In S4, graphite paper is attached to the inner wall of the jacket.

5. The preparation method of the copper-steel bimetallic part with a complex internal flow channel according to claim 1, characterized in that, In S6, the process of the hot isostatic pressing is as follows: heat up at a heating rate of 5°C / min - 10°C / min to 700°C - 1000°C, increase the pressure to 10MPa - 30MPa as the temperature rises, keep the temperature and pressure for 60min - 240min, and then cool down at a cooling rate of 2°C / min - 10°C / min to 100°C and then take out of the furnace.

6. The preparation method of the copper-steel bimetallic part with complex internal flow channels according to claim 1, characterized in that, In S2, the process of the cleaning treatment is as follows: immerse the primary copper alloy part in an acidic solution for cleaning, and then rinse and dry it with deionized water; In S5, the specific process of surface-treating and cleaning the stainless steel blank is as follows: first polish the inner wall of the stainless steel blank, then clean the surface of the stainless steel blank with gasoline, then clean the surface of the stainless steel blank with acetone, and finally blow dry the surface of the stainless steel blank with argon.

7. The preparation method of the copper-steel bimetallic part with complex internal flow channels according to claim 6, characterized in that, The acidic solution is a 10wt% - 15wt% nitric acid solution, the temperature of the acidic solution is 25°C - 40°C, and the cleaning time in the acidic solution is 3min - 10min.

8. The preparation method of the copper-steel bimetallic part with a complex internal flow channel according to claim 1, characterized in that, The specific process of S5 is as follows: After evacuating the internal vacuum degree of the welded jacket to ≤ 1.0×10 -2 Pa, heat the welded jacket to 350°C to 450°C, keep it warm for 2h to 4h, and then carry out sealing welding.

9. The preparation method of the copper-steel bimetallic part with a complex internal flow channel according to claim 1, characterized in that, The width of the cooling channel is 2mm - 3mm, the depth is 6mm - 8mm, the center distance between adjacent cooling channels is 2.2mm - 3.5mm, and the bottom thickness of the cooling channel is 1.2mm - 1.5mm.

10. A copper-steel bimetallic part with complex internal flow channels, characterized in that, The copper-steel bimetal part is prepared by the preparation method described in any one of claims 1 - 9.

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