A copper / steel bimetallic material and its CMT arc additive manufacturing method

Abstract

The present invention provides a copper / steel bimetallic material and a CMT arc additive manufacturing method thereof, comprising the following steps: establishing a CMT additive manufacturing system; cleaning and treating the contact surfaces of the substrate and the additive part to be welded; fixing the Q235 substrate on the welding platform with a clamp, and using ER120S-G high-strength steel welding wire to deposit a steel layer wall layer on the substrate layer by layer to form an "inverted T-shaped" metal part; using ERCuSi-A copper alloy welding wire to deposit a copper layer metal material layer by layer on the steel layer wall, extending the "1" portion of the "inverted T-shaped" metal part, and finally forming the copper / steel bimetallic material. The method solves the problems of long manufacturing cycle, complex process and environmental pollution of traditional copper / steel bimetallic materials, improves the mechanical properties of the copper / steel bimetallic material, and achieves a tensile strength of 404 MPa. The ER120S-G high-strength steel welding wire and the ERCuSi-A copper alloy welding wire have good metallurgical compatibility, and the mechanical properties at the copper / steel interface are better than those on the copper alloy side.

Description

Technical Field

[0001] The present invention relates to the technical field of manufacturing copper / steel bimetallic materials, and in particular to a CMT arc additive manufacturing technology that has high manufacturing efficiency, good product performance and low environmental pollution. Background Art

[0002] Bimetallic material is a type of composite material. It is a composite material composed of two or more materials with different physical, chemical or mechanical properties, which are metallurgically bonded at the interface under different processing techniques. The bimetallic material described in the present invention is a layered bimetallic material.

[0003] Bimetallic materials maintain their original composition, structure and properties on both sides of the interface. Metallurgical bonding occurs at the interface while a new phase different from the metals on both sides is formed. They have the characteristics of structural integration and functional diversity, and can solve problems such as the single performance of traditional materials, susceptibility to service environment restrictions and small application range.

[0004] Copper / steel bimetallic material is a new type of material composed of copper alloy and steel. It not only has the excellent electrical conductivity, thermal conductivity, wear resistance and corrosion resistance of copper alloy, but also has the advantages of high tensile strength and low cost of steel. It has broad application prospects in the automotive industry, electric power energy and construction fields.

[0005] Pure copper and copper alloys occupy a significant portion of the market for commonly used industrial metals. However, these materials often fracture and fail under harsh operating conditions due to poor mechanical properties, increasing repair costs and wasting resources. In recent years, as market demand for copper resources has increased, the price of copper and copper alloys has also increased year by year. These issues are bound to constrain the long-term development of copper materials in the future.

[0006] Steel is inexpensive and has excellent mechanical properties. Using copper / steel bimetallic materials instead of copper, which has only single-performance copper, maximizes the advantages of both, saving costs while improving the bimetallic's overall mechanical properties. Therefore, the development of copper / steel bimetallic materials offers excellent economic benefits and aligns with the development of a resource-conserving society.

[0007] Currently, the main preparation processes for copper / steel bimetallic materials include explosive cladding, powder metallurgy, and centrifugal casting. However, these traditional methods all suffer from drawbacks, including long manufacturing times, complex processes, and environmental pollution. Furthermore, data indicates that the tensile strength of copper / steel bimetallic materials produced using vacuum casting is 278 MPa.

[0008] The main technical solution adopted by this invention is to use the CMT arc additive manufacturing process to manufacture copper / steel bimetallic materials. Cold metal transfer additive manufacturing technology is a new short-circuit transfer process based on and improved on the MIG process, with low welding heat input, no spatter, and excellent forming quality.

[0009] The present invention utilizes the "hot and cold alternation" characteristics of CMT short-circuit transition to achieve better metallurgical bonding of the copper / steel bimetallic material at the copper / steel interface, thereby enhancing the overall mechanical properties of the material. CMT's unique additive manufacturing method allows additive parts to achieve high tensile strength without the need for subsequent complex heat treatment processes. This not only reduces post-weld residual stress and prevents cracks, but also shortens the process flow to a certain extent and improves production efficiency. The use of the CMT additive manufacturing process not only produces copper / steel bimetallic materials with excellent mechanical properties, maximizing the advantages of copper / steel bimetallic materials, but also saves costs to a certain extent, which is also in line with the current concept of energy conservation, carbon reduction, and green development. Summary of the Invention

[0010] The purpose of the present invention is to solve the problems of low manufacturing efficiency, poor product performance and severe environmental pollution in the traditional manufacturing of copper / steel bimetallic materials. By combining two metal materials with good metallurgical compatibility and good welding performance with CMT arc additive manufacturing technology, a method for manufacturing copper / steel bimetallic materials with reliable connection, high strength and rapid manufacturing is provided.

[0011] To achieve the above object, the present invention provides the following solutions:

[0012] The present invention provides a copper / steel bimetallic material and a CMT arc additive manufacturing method thereof, characterized by utilizing the interaction between the short-circuit transition principle of the CMT process and the chemical composition of the welding wire, comprising the following steps:

[0013] Step 1: Establish a CMT additive manufacturing system, debug various CMT process parameters, and simulate the CMT arc additive manufacturing process. Clean the Q235 experimental substrate and the contact surface of the additive part to be welded, including mechanical grinding and acetone wiping.

[0014] Step 2: Fix the Q235 experimental substrate on the welding platform with a fixture, and use ER120S-G high-strength steel welding wire to deposit steel layer walls on the substrate layer by layer to form an "inverted T-shaped" metal part as the "base metal" of the copper / steel bimetallic material;

[0015] Step 3: Using ERCuSi-A copper alloy welding wire, deposit copper metal material layer by layer on the steel wall, extending the "1" part of the "inverted T-shaped" metal part, and finally forming a copper / steel bimetallic material;

[0016] Step 4: Adjust the CMT arc additive manufacturing process parameters and repeat the above additive manufacturing process.

[0017] Preferably, the CMT additive manufacturing system mainly consists of five parts: a main power supply, a CMT welding machine, a shielding gas cylinder, a CNC computer port and a welding experimental platform.

[0018] Preferably, the ER120S-G high-strength steel welding wire has a diameter of 1.2 mm, and its main chemical components are: C-0.07wt%, Si-1.78wt%, Mn-0.74wt%, Ni-2.30wt%, Mo-0.59wt%, Cr-0.33wt%, Fe-Bal.wt%.

[0019] Preferably, the ERCuSi-A copper alloy welding wire has a diameter of 1.2 mm, and its main chemical components are: C-0.02wt%, Si-3.50wt%, Mn-1.30wt%, Zn-0.40wt%, P-0.05wt%, Fe-0.50wt%, Cu-Bal.wt%.

[0020] Preferably, the CMT arc additive manufacturing process uses a mixed gas of 80% argon + 20% carbon dioxide (steel part) and pure argon (copper part) as shielding gas, with a uniform gas flow rate of 20 L / min.

[0021] Preferably, the CMT arc additive manufacturing process parameters are: welding current 60 A ~ 160 A (steel part), welding speed 300 mm / min ~ 700 mm / min (steel part); welding current 70 A ~ 110 A (copper part), welding speed 400 mm / min ~ 800 mm / min (copper part).

[0022] Preferably, in the CMT arc additive manufacturing process, the dry extension of the welding wire is 12 mm, the CNC end controls the welding gun movement path in a reciprocating manner, the welding gun is raised by about 2 mm after each layer is deposited, and the additive part is cooled for 5 minutes after each layer is deposited.

[0023] Preferably, the copper / steel bimetallic material is manufactured by the above method.

[0024] Compared with the prior art, the present invention has achieved the following beneficial technical effects:

[0025] The copper / steel bimetallic materials used in this invention (i.e., ER120S-G high-strength steel welding wire and ERCuSi-A copper alloy welding wire) were developed by the authors through research on various copper alloys and steels and have not been used in related research. Furthermore, the ER120S-G high-strength steel welding wire and the ERCuSi-A copper alloy welding wire exhibit good metallurgical compatibility, resulting in superior mechanical properties at the copper / steel interface compared to the copper alloy side. The copper / steel bimetallic material produced using the CMT arc additive manufacturing process achieves a tensile strength of 404 MPa, a 45% increase compared to the 278 MPa achieved by vacuum casting. The CMT additive manufacturing process employed in this invention is a novel manufacturing technology characterized by low heat input, zero post-weld spatter, and excellent form quality. This invention utilizes the "alternating hot and cold" characteristics of CMT short-circuit transitions to achieve a better metallurgical bond at the copper / steel interface, thereby enhancing the overall mechanical properties of the material.

[0026] CMT's unique additive manufacturing method enables additive parts to achieve high tensile strength without requiring complex subsequent heat treatment. This not only reduces post-weld residual stress and prevents cracking, but also shortens the process flow and improves production efficiency. Compared with explosive composite methods, it not only reduces environmental pollution and resource waste, but also creates a copper / steel interface with uniform structure and stable performance. Compared with powder metallurgy, it improves the mechanical properties of copper / steel bimetallic materials and facilitates the manufacture of large mechanical parts. Compared with centrifugal casting, the CMT additive manufacturing process has lower equipment requirements and also helps improve the mechanical properties of the interface.

[0027] In addition, the use of CMT arc additive manufacturing of copper / steel bimetallic materials can obtain copper / steel bimetallic materials with good performance without the need for transition layer composites, which saves production costs to a certain extent; and for large and complex structural parts, its production efficiency is much higher than that of laser and electron beam additive manufacturing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 A schematic diagram of the CMT arc additive manufacturing process for copper / steel bimetallic materials provided by the present invention.

[0030] Figure 2 A schematic diagram of the dimensions of a tensile specimen of a copper / steel bimetallic material produced by CMT arc additive manufacturing provided by the present invention.

[0031] Figure 3 This is a stress-strain curve of a tensile specimen of a copper / steel bimetallic material manufactured by CMT arc additive manufacturing provided by the present invention.

[0032] Figure 4 The fracture position of a tensile specimen of a copper / steel bimetallic material produced by CMT arc additive manufacturing provided by the present invention. Implementation Method

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] The purpose of the present invention is to solve the problems of low manufacturing efficiency, poor product performance and severe environmental pollution in the traditional manufacturing of copper / steel bimetallic materials. By combining two metal materials with good metallurgical compatibility and good welding performance with CMT arc additive manufacturing technology, a method for manufacturing copper / steel bimetallic materials with reliable connection, high strength and rapid manufacturing is provided.

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. Example

[0036] This embodiment provides a copper / steel bimetallic material and a CMT arc additive manufacturing method thereof, characterized by utilizing the short-circuit transfer principle of the CMT process and the interaction between the chemical composition of the welding wire. The process includes the following steps:

[0037] Step 1: Build a CMT additive manufacturing system, which consists of five main components: a power supply, a CMT welding machine, a shielding gas cylinder, a CNC computer port, and a welding experimental platform. CMT welding can be performed using an Austrian CMT-TPS3200 welding machine. Connect the CMT welding gun to the computer port, and the CNC program precisely controls the direction, distance, and speed of the gun's movement.

[0038] Step 2: Mechanically polish the 4.0 mm thick Q235 test substrate to be welded and wipe the oil stains on the metal surface with acetone to ensure a pollution-free CMT additive environment. At the same time, firmly fix the test substrate to be welded on the welding platform to prevent deformation due to local heating. Then perform a CMT additive simulation test weld, adjust the initial point of the additive deposition path, perform a test weld without arcing, and return to the initial point.

[0039] Step 3: A single-pass, single-layer, single-metal deposition experiment of steel material was carried out on a Q235 substrate using an ER120S-G high-strength steel welding wire with a diameter of 1.2 mm. The welding current was set to 60 A ~ 160 A, the welding speed was set to 300 mm / min ~ 700 mm / min, and the shielding gas flow rate was fixed at 20 L / min with a mixed gas of 80% argon and 20% carbon dioxide.

[0040] Step 4: Using a 1.2 mm diameter ER120S-G high-strength steel welding wire, a single-pass, multi-layer, single-metal deposition experiment was conducted on a Q235 substrate. A reciprocating path was used to deposit the steel wall layer by layer along the predetermined deposition route, forming an "inverted T-shaped" metal part. The wall portion had a length l1 of 150 mm, a width w1 of 3-5 mm, and a height h1 of 10-15 mm. A shielding gas mixture of 80% argon and 20% carbon dioxide was used throughout the process, with a gas flow rate of 20 L / min. The additively manufactured part was then subjected to wire cutting. The optimal process parameters for the steel layer, based on optimal tensile strength, were determined to be a welding current of 100 A and a welding speed of 550 mm / min.

[0041] Step 5. Use an ERCuSi-A copper alloy welding wire with a diameter of 1.2 mm to perform a single-pass, single-layer, single-metal deposition experiment on a copper alloy material on a substrate. Set the welding current to 70 A ~ 110 A, the welding speed to 400 mm / min ~ 800 mm / min, and the shielding gas pure argon gas flow rate to 20 L / min. Measure the weld width and reinforcement height of the copper alloy. Under the premise of ensuring the performance of the copper alloy, explore the process parameter range that best matches the steel material, so as to carry out the next single-pass, multi-layer experiment of the copper / steel bimetallic material.

[0042] Step 5: Figure 1 As shown, a 1.2 mm diameter ERCuSi-A copper alloy welding wire is used. On the steel wall obtained under the optimal process parameters, a reciprocating walking path is used to deposit copper alloy metal layer by layer according to different process parameters. The "1" part of the "inverted T-shaped" metal part is extended. The length and width of the copper layer are adapted to the steel layer metal. The height h2 is 10-15 mm. The operation is protected by pure argon gas throughout the process with a gas flow rate of 20 L / min. The final copper / steel bimetallic material is formed. The additive parts are wire-cut according to GB / T228.1-2021 "Tensile Test of Metallic Materials Part 1: Room Temperature Test Method", as shown. Figure 2 As shown in the figure. Under the conditions of 100 A welding current and 500 mm / min welding speed, the tensile strength of copper / steel bimetallic material reaches the best 404 MPa. Figure 3 As shown; and the tensile specimen broke at the copper side metal, indicating that the mechanical properties at the copper / steel interface are better than those at the copper alloy side, as shown Figure 4 shown.

[0043] It should be noted that the implementation of the CMT additive manufacturing system can use different CNC programs or welding robots to plan the movement path of the welding gun, and then manufacture the same metal parts. The role of the welding robot is to realize the movement of the welding gun during the additive process. In addition to the CNC numerical control system used in the present invention, other robots or servo motors can also be used to achieve this.

[0044] Secondly, the present invention uses CMT additive manufacturing technology to manufacture copper / steel bimetallic walls. Based on tensile strength, the present invention obtains additive process parameters suitable for the manufacture of ER120S-G high-strength steel and ERCuSi-A copper alloy. These parameters are not limited to the manufacture of wall parts and are also applicable to copper / steel bimetallic parts of other shapes and sizes besides walls.

[0045] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A CMT arc additive manufacturing method for copper / steel bimetallic materials, characterized in that The interaction between the short-circuit transfer principle of the CMT process and the chemical composition of the welding wire includes the following steps: Step 1: Establish a CMT additive manufacturing system, debug various CMT process parameters, and simulate the CMT arc additive manufacturing process. Clean the Q235 experimental substrate and the contact surface of the additive part to be welded, including mechanical grinding and acetone wiping. Step 2: Fix the Q235 experimental substrate on the welding platform with a fixture, and use ER120S-G high-strength steel welding wire to deposit steel layer walls on the substrate layer by layer to form an "inverted T-shaped" metal part as the "base metal" of the copper / steel bimetallic material; Step 3: Using ERCuSi-A copper alloy welding wire, deposit copper metal material layer by layer on the steel wall, extending the "1" part of the "inverted T-shaped" metal part, and finally forming a copper / steel bimetallic material; Step 4: Adjust the CMT arc additive manufacturing process parameters and repeat the above additive manufacturing process; The ER120S-G high-strength steel welding wire has a diameter of 1.2 mm and its main chemical composition is: C-0.07wt%, Si-1.78wt%, Mn-0.74wt%, Ni-2.30wt%, Mo-0.59wt%, Cr-0.33wt%, Fe-Bal.wt%; The ERCuSi-A copper alloy welding wire has a diameter of 1.2 mm and its main chemical composition is: C-0.02wt%, Si-3.50wt%, Mn-1.30wt%, Zn-0.40wt%, P-0.05wt%, Fe-0.50wt%, Cu-Bal.wt%; The CMT arc additive manufacturing process parameters are as follows: ① Steel part: welding current 60 A to 160 A, welding speed 300 mm / min to 700 mm / min; ② Copper part: welding current 70 A to 110 A, welding speed 400 mm / min to 800 mm / min.

2. The CMT arc additive manufacturing method for copper / steel bimetallic materials according to claim 1, characterized in that: The CMT additive manufacturing system is mainly composed of five parts: a main power supply, a CMT welding machine, a shielding gas cylinder, a CNC computer port and a welding experimental platform.

3. The CMT arc additive manufacturing method for copper / steel bimetallic materials according to claim 1, characterized in that: In the CMT arc additive manufacturing process, a mixed gas of 80% argon and 20% carbon dioxide is used as the shielding gas for the steel portion, and pure argon is used as the shielding gas for the copper portion, with a gas flow rate of 20 L / min for both.

4. The CMT arc additive manufacturing method for copper / steel bimetallic materials according to claim 1, characterized in that: In the CMT arc additive manufacturing process, the dry extension of the welding wire is 12 mm, the CNC end controls the welding gun's travel path in a reciprocating manner, the welding gun is raised by about 2 mm after each layer is deposited, and the additive part is cooled for 5 minutes after each layer is deposited.

5. A copper / steel bimetallic material, characterized in that: The copper / steel bimetallic material is manufactured by the manufacturing method according to any one of claims 1 to 4. The obtained copper / steel bimetallic material has a tensile strength of up to 404 MPa, and the mechanical properties at the copper / steel interface are better than those on the copper alloy side.

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