Low-temperature plasma additive manufacturing device adopting in-situ cooling and hot wire technology and manufacturing method of low-temperature plasma additive manufacturing device

Abstract

The invention discloses a low-temperature plasma additive device adopting an in-situ cooling and hot wire technology and a manufacturing method of the low-temperature plasma additive device, and belongs to the technical field of additive manufacturing. A plasma additive process is adopted to melt a welding wire and deposit the welding wire on a substrate, and part of current is conducted to the welding wire through a plasma wire heating system to play a role in preheating and shunting; when the plasma welding gun carries out welding in the front, an in-situ cooling system is arranged behind the plasma welding gun, and the in-situ cooling system is arranged behind the plasma welding gun, keeps synchronous with the plasma welding gun, keeps relative movement with the workpiece, and rapidly cools a cladding layer at the speed the same as the welding speed; low-heat-input additive manufacturing is carried out on a plasma additive manufacturing system by adopting compressed CO2 gas in-situ cooling and hot wire shunting technologies, and the interference of cooling gas on a compressed arc is reduced through debugging of a process scheme. And in the large-scale production of the steel-nickel composite structure, the production period can be remarkably shortened, the energy consumption is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the cross - field of additive manufacturing and welding technology, and particularly relates to a low - temperature plasma additive manufacturing device with in - situ cooling collaborative hot - wire technology and its manufacturing method. Background Art

[0002] In recent years, more and more scholars have found that the coarse grains in the overlapping areas of additive specimens can lead to the deterioration of the strength and plasticity of components, becoming the fundamental reason for the premature failure of additive manufacturing samples. However, during the wire and arc additive manufacturing (WAAM) process, the high heat generated by the arc heat source is inevitable. Research shows that the deposition parameters of WAAM have a significant impact on the heat input. Although optimizing the key deposition parameters (current, voltage, and welding speed) does help to control the heat input, the range that can be formulated is usually limited. To further regulate the heat input, controlling the shape and properties by controlling the interlayer temperature has become the mainstream research direction. Prolonging the interlayer residence time has been proven to be effective, but it will undoubtedly reduce the deposition rate. Interlayer cooling, substrate cooling, and active cooling (such as air flow or water cooling) reduce heat accumulation by accelerating heat dissipation. For example, near - immersion active cooling (NIAC) keeps the component at a low temperature through water cooling, significantly reducing porosity and improving geometric accuracy, while reducing mechanical property anisotropy. However, the cooling method needs to be precisely controlled to avoid stress concentration caused by over - cooling, and the above methods all face challenges in terms of efficiency, cost, or process adaptability. Summary of the Invention

[0003] The purpose of the present invention is to address the deficiencies existing in the prior art. To achieve the effects of in - situ interlayer cooling and low - heat - input arc additive manufacturing during the additive manufacturing process, the present invention proposes a low - temperature plasma additive manufacturing method with in - situ cooling collaborative hot - wire technology, providing a solution for realizing an efficient - high - quality - low - stress - deformation additive manufacturing process.

[0004] The present invention provides a low - temperature plasma additive manufacturing device with in - situ cooling collaborative hot - wire technology, including a plasma hot - wire system, a plasma welding torch, an intelligent measurement and control system, and an in - situ cooling system; the in - situ cooling system includes a compressed gas spray head and a cooling gas storage tank controlled by a gas flow regulator; the internal components of the intelligent measurement and control system include a temperature acquisition device and a total gas flow controller; the negative pole of the plasma hot - wire system is respectively connected to the plasma welding torch and the intelligent measurement and control system, and the positive pole is connected to the substrate; the intelligent measurement and control system is respectively connected to the cooling gas storage tank and the argon gas storage tank through a gas flow control device.

[0005] The present invention further provides a manufacturing method of a low-temperature plasma additive device with in-situ cooling and synergistic hot wire technology. The plasma additive process is used to melt the welding wire and deposit it on the substrate. Part of the current is conducted to the welding wire through the plasma hot wire system to play a role in preheating and shunting. When the plasma welding torch is welding in the front, an in-situ cooling system is arranged behind the plasma welding torch. The in-situ cooling system follows behind the plasma welding torch and keeps in sync with the plasma welding torch, maintaining relative movement with the workpiece to rapidly cool the cladding layer at the same speed as the welding speed. The in-situ cooling system increases the undercooling degree and cooling rate of the molten pool through compressed gas, inhibits dendrite growth and solute segregation, and promotes the formation of equiaxed crystals. The intelligent measurement and control system collects the temperature information of the cladding layer in real time through the temperature acquisition device and transmits it back to the gas flow control device to adjust the flow rates of the cooling gas and the shielding gas in real time, so as to ensure that the interlayer temperature is controlled below 50°C, reduce the redistribution time of solute elements, and form a more uniform and refined microstructure.

[0006] Further, the manufacturing method specifically includes the following steps:

[0007] Step 1: Connect the low-temperature plasma additive manufacturing device with in-situ cooling and synergistic hot wire technology, fix the position of the substrate, and at the same time adjust the starting and ending positions of the additive and the distance between the shielding gas cover at the bottom of the plasma welding torch and the substrate.

[0008] Step 2: Turn on the plasma hot wire system, the cooling gas storage tank, the plasma welding torch, the argon storage tank, and the intelligent measurement and control system.

[0009] Step 3: The intelligent measurement and control system sends a control signal to start the walking mechanism arranged with the substrate. The plasma welding torch is at the starting position, and then the flow regulator is started to start the compressed cooling gas. The cooling gas escapes from the compressed gas nozzle after the plasma welding torch starts to move.

[0010] Step 4: The intelligent measurement and control system collects the temperature information of the cladding layer through the temperature acquisition device and transmits it back to the gas flow control device to adjust the flow rate of the cooling gas in real time.

[0011] Step 5: Perform additive manufacturing according to the predetermined path. When the plasma welding torch reaches the arc-ending position, first, the intelligent measurement and control system sends a control signal to the wire feeder to stop wire feeding, then sends a signal to the power supply of the plasma welding torch to extinguish the plasma welding torch, and sends a control signal to the gas flow control device to stop the ejection of the cooling gas and the shielding gas.

[0012] Step 6: According to the path designed for the additive, repeat steps 1 to 5 until the construction of the additive sample is completed.

[0013] Further, the current of the plasma welding torch is 40 - 120 A, and the current of the plasma hot wire system is 20 - 80 A.

[0014] Furthermore, the flow rate of the shielding gas is 15 - 20 L / min, the flow rate of the ionic gas is 1 - 3 L / min, and the flow rate of the cooling gas is 30 - 50 L / min.

[0015] Furthermore, the additive manufacturing speed V1 is 4 - 10 mm / s, and the wire feeding speed is 2 - 5 m / min.

[0016] Furthermore, the compressed gas nozzle of the in-situ cooling system is located 5 - 10 cm behind the plasma welding torch; the gas in the cooling gas storage tank is a gas-solid mixed CO2 at -78°C.

[0017] Furthermore, the cooling rate R of the in-situ cooling c has the following designed relationship with the distance d from the compressed gas nozzle (13) to the surface of the molten pool:

[0018]

[0019] wherein, R c is the cooling rate, representing the rate at which the temperature of the material decreases per unit time during additive manufacturing; k is the heat transfer coefficient of the cooling medium; ΔT is the temperature difference, i.e., the difference between the temperature of the molten pool surface and the temperature of the cooling medium; d is the distance from the nozzle to the molten pool surface, representing the geometric distance from the nozzle position to the cooling target; n is the distance attenuation exponent; η is the cooling efficiency factor, 0 < η ≤ 1.

[0020] The present invention also provides a steel-nickel composite structural member, and the average hardness of the additive structure of the steel-nickel composite structural member is 200 - 250 HV.

[0021] The present invention also provides an application of a steel-nickel composite structural member in additive manufacturing of an anti-corrosion layer for shipbuilding.

[0022] The beneficial effects of the present invention are as follows:

[0023] The low-temperature plasma additive manufacturing process of the in-situ cooling collaborative hot wire technology of the present invention can preheat the metal wire while reducing the heat input. During the additive manufacturing process, the interlayer cooling efficiency and the undercooling of the molten pool are greatly improved, and while refining the grains, the additive manufacturing efficiency is significantly increased. The hot wire system realizes the resistance preheating effect of the wire by transferring part of the current in the plasma power supply, and at the same time realizes the beneficial effect of shunting to reduce the heat input. While preheating the wire, the current flowing through the base material is reduced, realizing the additive manufacturing effect of melting the wire with low heat input. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of the low-temperature plasma additive manufacturing method of the in-situ cooling collaborative hot wire technology of the present invention;

[0025] Figure 2Macromorphology diagram of the additive specimen of the low-temperature plasma additive manufacturing method with in-situ cooling collaborative hot wire technology in Example 1;

[0026] Figure 3 Macromorphology diagram of the additive specimen of the plasma additive manufacturing method in Comparative Example 1;

[0027] Figure 4 Hardness distribution diagram of the additive specimens in Example 1 and Comparative Example 1.

[0028] Reference numerals are: 1. Wire feeder; 2. Argon gas cylinder; 3. Wire guide pulley; 4. Wire feeding tube; 5. Tooling fixture; 6. Protective gas hood; 7. Additive component; 8. Substrate; 9. Traveling mechanism; 10. Plasma hot wire power supply; 11. Cooling gas storage tank; 12. Gas flow regulator; 13. Compressed gas spray head; 14. Plasma welding torch; 15. Intelligent measurement and control system; 16. Temperature acquisition device; 17. Gas flow control device. Detailed implementation manners

[0029] The present invention will be further described below with reference to the accompanying drawings.

[0030] As Figure 1 , the present invention discloses a low-temperature plasma additive manufacturing device with in-situ cooling collaborative hot wire technology, mainly including a plasma hot wire additive manufacturing device, a cladding layer intelligent measurement and control system 15, and an in-situ cooling system; the internal components of the intelligent measurement and control system 15 include a temperature acquisition device 16 and a gas flow control device 17; the in-situ cooling system includes a compressed gas spray head 13 and a cooling gas storage tank 11 controlled by a gas flow regulator 12.

[0031] The plasma hot wire additive manufacturing device generates a welding torch by a plasma arc welding power supply to melt the welding wire. Among them, a hot wire system is connected, and part of the plasma current flows through the welding wire to achieve the effect of resistance hot wire, so that it can be fully preheated before additive manufacturing and more easily reach the melting point of the metal; the wire feeding tube 4 and the original compressed gas spray head 13 are fixed by a tooling fixture to ensure that the axis of the wire feeding tube 4 intersects with the axis of the welding torch at a point, achieving the effect that the position where the welding wire extends is at the center of the welding torch, and ensuring a certain distance between the compressed gas spray head 13 and the welding torch to avoid the cooling gas jet interfering with the additive manufacturing effect; the substrate is fixed on the traveling mechanism 9, and the substrate moves horizontally with the traveling mechanism. At the same time, the mechanism for adjusting the welding torch can be adjusted for the vertical position. The intelligent measurement and control system 15 collects the temperature information of the cladding layer in real time through the temperature acquisition device 16 and transmits it back to the gas flow control device 17 to adjust the flow rate of the cooling gas in real time.

[0032] The present invention discloses a low-temperature plasma additive manufacturing method with in-situ cooling collaborative hot wire technology, including the following steps:

[0033] Step 1: During additive manufacturing, select the process parameters of plasma hot wire fusing according to the diameter of the welding wire in the wire feeder 1, fix the position of the substrate through the tooling fixture, adjust the traveling mechanism 9 to determine the starting and ending positions of additive manufacturing, and at the same time determine the height of the bottom end of the welding torch protection gas hood 6 from the substrate to adjust the arc length to meet the requirements of additive manufacturing;

[0034] Step 2: Start the plasma hot wire power supply 10, gas flow regulator, protective gas, and intelligent measurement and control system 15;

[0035] Step 3: The intelligent measurement and control system sends out a control signal to start the traveling mechanism 9. The traveling platform drives the substrate to move, so that the plasma welding torch is in the starting position. Then start the gas flow regulator 12 to release compressed cooling gas to provide a stable carbon dioxide cooling flow. The cooling spray starts after the welding torch starts to move and is at a certain distance from the torch to avoid arc damage caused by relatively turbulent CO2 flow.

[0036] Step 4: The temperature acquisition device 16 collects the temperature information of the cladding layer in real time and transmits it back to the gas flow control device 17 to adjust the flow rate of the cooling gas in real time.

[0037] Step 5: Carry out additive manufacturing according to the predetermined path. When the welding torch reaches the arc extinguishing position, first, the intelligent measurement and control system 15 sends a control signal to the wire feeder 1 to stop wire feeding, then sends a signal to the plasma arc welding power supply to extinguish the plasma welding torch 14, and sends a control signal to the gas flow control device 17 to stop the spraying of the cooling gas and the protective gas.

[0038] Step 6: Repeat the above steps according to the path designed for additive manufacturing until the construction of the additive specimen is completed.

[0039] The above uses the plasma hot wire additive process to melt the welding wire and deposit it on the substrate. Part of the current is conducted to the welding wire through the hot wire system to play the role of preheating and shunting. High-purity argon gas is used for protection inside the welding torch. Cooling gas nozzles are arranged at a position 5 - 10 cm behind the traveling direction. The gas-solid mixed CO2 at -78°C is used to quickly cool the deposition layer to complete the in-situ cooling plasma hot wire additive process.

[0040] The above plasma current I1 is 40 - 120 A, the hot wire current I2 is 20 - 80 A, the protective gas flow rate Q1 is 15 - 20 L / min, the ion gas flow rate Q2 is 1 - 3 L / min, the cooling gas flow rate is 30 - 50 L / min, the additive manufacturing speed V1 is 4 - 10 mm / s, and the wire feeding speed V2 is 2 - 5 m / min.

[0041] Among them, based on Newton's law of cooling q = k·δT and the geometric attenuation characteristics of nozzle cooling (similar to inverse square or linear attenuation). Summarize the relationship between the in-situ cooling nozzle position and the cooling rate to describe the cooling rate Rc Association with the nozzle position.

[0042]

[0043] Wherein, R c is the cooling rate, representing the rate at which the temperature of the material decreases per unit time during additive manufacturing; k is the heat transfer coefficient of the cooling medium; ΔT is the temperature difference, i.e., the difference between the temperature of the molten pool surface and the temperature of the cooling medium; d is the distance between the nozzle and the molten pool surface, representing the geometric distance from the nozzle position to the cooling target; n is the distance attenuation exponent; η is the cooling efficiency factor (0 < η ≤ 1).

[0044] The temperature distribution of the deposited metal is collected by the above infrared temperature camera. The preheating temperature T1 of the welding wire before the plasma arc is ignited is 80 - 120 °C, and the temperature T2 of the cladding layer during the additive process is below 50 °C.

[0045] Example 1

[0046] A low-temperature plasma additive manufacturing method using in-situ cooling and synergistic hot wire technology, comprising:

[0047] Step 1: During additive manufacturing, a C276 nickel-based alloy welding wire with a diameter of 1.2 mm is selected. According to the diameter of the welding wire in the wire feeder 1, the process parameters of the plasma hot wire melting are selected. The plasma current I1 is 120 A, the hot wire current I2 is 80 A, the gas flow rate Q1 of the shielding gas argon is 15 L / min, the gas flow rate Q2 of the ion gas is 1.5 L / min, the gas flow rate Q3 of the cooling gas is 50 L / min, the additive speed V1 is 6 mm / s, and the wire feeding speed V2 is 4.5 m / min.

[0048] Step 2: Fix the position of the AH36 steel substrate through the tooling fixture, adjust the walking mechanism 9 to determine the starting and ending positions of the additive manufacturing, and at the same time determine the height of the bottom end of the welding gun shielding gas hood 6 from the substrate to adjust the arc length to meet the requirements of additive manufacturing;

[0049] Step 3: Start the low-temperature plasma additive manufacturing device using in-situ cooling and synergistic hot wire technology; turn on the plasma hot wire system 10, the gas flow controller 12, and the intelligent measurement and control system 15;

[0050] Step 4: The intelligent measurement and control system sends out a control signal to start the traveling mechanism 9, so that the plasma welding torch 14 is in the starting position, and the traveling platform drives the substrate to move at a speed of V1 = 6 mm / s; start the flow regulator 12 to release the compressed cooling gas, and the compressed gas is evenly ejected at a speed of Q3 = 50 L / min; the cooling spray starts after the plasma welding torch 14 starts to move, the nozzle position is 5 cm away from the plasma welding torch, and the nozzle position is 8 cm away from the molten pool to avoid arc damage caused by the relatively turbulent CO2 flow; collect the temperature information of the cladding layer in real time through the temperature acquisition device and send it back to the total gas flow controller 17 to adjust the flow rates of the cooling gas and the shielding gas in real time to ensure that the interlayer temperature is controlled below 50°C;

[0051] Step 5: Perform additive manufacturing according to the predetermined path. When the plasma welding torch 14 reaches the arc extinguishing position, first, the intelligent measurement and control system 15 sends a control signal to the wire feeder 1 to stop wire feeding, then sends a signal to the plasma arc welding power source to extinguish the plasma arc between the plasma welding torch 14 and the substrate 8, and sends a control signal to the gas flow control device 17 to stop the ejection of the cooling gas;

[0052] Step 6: Repeat the above steps according to the additive design path until the construction of the additive specimen is completed.

[0053] As Figure 2 shown, in-situ cooling improves the undercooling degree and cooling rate of the molten pool by compressed gas (-78°C CO2, flow rate 30 - 50 L / min), inhibits dendrite growth and solute segregation, and promotes the formation of equiaxed crystals. Figure 2 shows that the dendrites of the specimen in Example 1 are refined and do not coarsen with the increase in the number of thermal cycles, and the change in dendrite orientation is more obvious, indicating that lower heat input reduces the redistribution time of solute elements and forms a more uniform microstructure.

[0054] In the additive manufacturing of C276 nickel-based alloy on an AH36 steel substrate, this refined microstructure reduces the formation of intermetallic compounds at the interface, improves the interface bonding strength, and reduces the risk of interface cracks.

[0055] Comparative Example 1

[0056] The difference from Example 1 is that Comparative Example 1 does not adopt the hot wire technology and in-situ cooling technology, and only uses the plasma additive manufacturing method to prepare the additive specimen, and the parameter settings are the same as those in Example 1.

[0057] The additive specimen prepared by Comparative Example 1 using plasma additive manufacturing is as Figure 3 shown, and the specimen in the figure has relatively thick columnar crystals and long dendrites ( Figure 2 c-f).

[0058] From the specimen of Example 1Figure 2 and the specimen of Comparative Example 1 Figure 3 it can be seen that compared with Figure 3 , Figure 2 in the specimen, fine equiaxed grains and short dendrites ( Figure 3 e-g) are dominant, the grain refinement is obvious, and the formation of columnar grains and orientation-disordered dendrites is reduced. This tissue optimization enhances the isotropy and uniformity of mechanical properties, reduces thermal stress and crack tendency, and improves the quality and reliability of additive manufacturing components. The specimen of Example 1 significantly reduces the heat input and increases the cooling rate through in-situ cooling combined with hot wire technology, optimizing the microstructure morphology.

[0059] Figure 4 As shown in

[0060] , the average hardness of the C276 nickel-based alloy specimen added on the AH36 steel substrate increases from 199.8 HV (comparative example plasma additive technology) to 222.8 HV, with an increase of 11.51%, and the hardness distribution is more uniform along the vertical direction. This is attributed to the reduction of precipitation phases and grain refinement during cooling with welding. For the steel-nickel composite structure, the higher hardness and uniform mechanical properties of the C276 nickel-based alloy specimen added on the AH36 steel substrate enhance the durability of the component in a complex stress environment and are applicable to high-load and high-corrosion environments.

[0061] The above description shows and describes the preferred embodiments of the present invention. As mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications, and environments, and can be changed within the scope of the inventive concept described herein through the above teachings or the technology or knowledge in related fields. And any changes and modifications made by those skilled in the art without departing from the spirit and scope of the present invention should fall within the protection scope of the appended claims of the present invention.

Claims

1. A cryogenic plasma additive manufacturing device using in-situ cooling and collaborative hot wire technology, characterized in that It includes a plasma hot wire system (10), a plasma welding torch (14), an intelligent measurement and control system (15), and an in-situ cooling system; the in-situ cooling system includes a compressed gas nozzle (13) and a cooling gas storage tank (11) controlled by a gas flow regulator (12); the internal components of the intelligent measurement and control system (15) include a temperature acquisition device (16) and a total gas flow controller (17); the negative electrode of the plasma hot wire system (10) is respectively connected to the plasma welding torch (14) and the intelligent measurement and control system (15), and the positive electrode is connected to the substrate; the intelligent measurement and control system (15) is respectively connected to the cooling gas storage tank (11) and the argon storage tank (2) through a gas flow control device (17).

2. A manufacturing method of a cryogenic plasma additive device adopting the in-situ cooling collaborative hot wire technology described in claim 1, characterized in that, The plasma additive manufacturing process is used to melt the welding wire and deposit it on the substrate. Part of the current is conducted to the welding wire through the plasma hot wire system (10) to play a role in preheating and current shunting; when the plasma welding torch (14) is welding in the front, an in-situ cooling system is arranged behind the plasma welding torch (14). The in-situ cooling system follows behind the plasma welding torch (14) and keeps in sync with it, and maintains relative movement with the workpiece to rapidly cool the cladding layer at the same speed as the welding speed; the in-situ cooling system increases the undercooling degree and cooling rate of the molten pool through compressed gas, inhibits dendrite growth and solute segregation, and promotes the formation of equiaxed crystals; the intelligent measurement and control system collects the temperature information of the cladding layer in real time through the temperature acquisition device (16) and transmits it back to the gas flow control device (17) to adjust the flow rates of the cooling gas and the shielding gas in real time, so as to ensure that the interlayer temperature is controlled below 50°C, reduce the redistribution time of solute elements, and form a more uniform and refined microstructure.

3. The manufacturing method of the low-temperature plasma additive device with in-situ cooling and collaborative hot wire technology according to claim 2, characterized in that, It includes: Step 1: Connect the low-temperature plasma additive manufacturing device with in-situ cooling collaborative hot wire technology, fix the position of the substrate, and at the same time adjust the start and end positions of the additive manufacturing and the distance between the shielding gas cover (6) at the bottom of the plasma welding torch (14) and the substrate; Step 2: Turn on the plasma hot wire system (10), the cooling gas storage tank (11), the plasma welding torch (14), the argon storage tank (2), and the intelligent measurement and control system (15); Step 3: The intelligent measurement and control system (15) sends a control signal to start the walking mechanism (9) arranged with the substrate. The plasma welding torch (14) is at the starting position, and then the flow regulator (12) is started to start the compressed cooling gas, and the cooling gas escapes from the compressed gas nozzle (13) after the plasma welding torch (14) starts to move; Step 4: The intelligent measurement and control system (15) collects the temperature information of the cladding layer through the temperature acquisition device (16) and transmits it back to the gas flow control device (17) to adjust the flow rate of the cooling gas in real time; Step 5: Conduct additive manufacturing according to a predetermined path. When the plasma welding torch (14) reaches the arc extinguishing position, first, the intelligent measurement and control system (15) sends a control signal to the wire feeder to stop wire feeding, then sends a signal to the power supply of the plasma welding torch (14) to extinguish the plasma welding torch (14), and sends a control signal to the gas flow control device (17) to stop the ejection of the cooling gas and the shielding gas; Step 6: Repeat Steps 1 to 5 according to the path of additive design until the construction of the additive specimen is completed.

4. The manufacturing method of the low-temperature plasma additive manufacturing device with in-situ cooling and synergistic hot wire technology according to claim 3, characterized in that, The current of the plasma welding torch (14) is 40 - 120 A, and the current of the plasma hot wire system (10) is 20 - 80 A.

5. The manufacturing method of the low-temperature plasma additive device with in-situ cooling and synergistic hot wire technology according to claim 3, characterized in that, The gas flow rate of the argon storage tank (2) is 15 - 20 L / min, the ion gas flow rate is 1 - 3 L / min, and the cooling gas flow rate is 30 - 50 L / min.

6. The manufacturing method of the low-temperature plasma additive device with in-situ cooling and synergistic hot wire technology according to claim 3, characterized in that, The additive speed V1 is 4 - 10 mm / s, and the wire feeding speed is 2 - 5 m / min.

7. The manufacturing method of the low-temperature plasma additive manufacturing device with in-situ cooling and synergistic hot wire technology according to claim 3, characterized in that, The compressed gas nozzle (13) of the in-situ cooling system is located 5 - 10 cm behind the plasma welding torch (14); the gas in the cooling gas storage tank (11) is a gas-solid mixed CO2 at -78°C.

8. The manufacturing method of the cryogenic plasma additive device of the in-situ cooling collaborative hot wire technology according to claim 1, characterized in that The in-situ cooling cooling rate R c The design relationship between the distance d from the compressed gas spray head (13) to the surface of the molten pool is as follows: Wherein, R c is the cooling rate, representing the rate of temperature decrease per unit time of the material during additive manufacturing; k is the heat transfer coefficient of the cooling medium; ΔT is the temperature difference, that is, the difference between the temperature of the molten pool surface and the temperature of the cooling medium; d is the distance between the nozzle and the molten pool surface, representing the geometric distance from the nozzle position to the cooling target; n is the distance attenuation exponent; η is the cooling efficiency factor, where 0 < η ≤ 1.

9. A steel-nickel composite structural member manufactured by using the additive manufacturing method according to claim 2, characterized in that, The average hardness of the additive structure of the steel-nickel composite structure member is 200 - 250 HV.

10. The steel-nickel composite structure member according to claim 9 is applied to the additive of the anti-corrosion layer in shipbuilding.

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