Method for manufacturing nickel-based alloy through TIG cold welding additive

Abstract

The invention provides a method for manufacturing a nickel-based alloy through TIG cold welding additive manufacturing. The method specifically comprises the steps that firstly, the surface of a base material is treated; the two ends of the nickel-based alloy welding wire are fixed to the base plate; then pulse current and pulse time are set on the precise cold welding machine; the TIG welding gun is powered on to ignite an electric arc to conduct electric arc remelting operation, the TIG welding gun moves along the nickel-based alloy welding wire, a series of continuous deposition points are formed on the nickel-based alloy welding wire, and single-pass nickel-based alloy deposition is completed; and repeating the single-pass nickel-based alloy deposition process to finish multi-pass nickel-based alloy deposition. And layer-by-layer stacking deposition is carried out until manufacturing of the nickel-based alloy deposition layers with the specified number is completed. A nickel-based alloy deposition layer obtained after TIG cold welding and material increase are completed is smooth in surface, free of obvious cracks, good in compactness, tight in interlayer combination and free of layering or separation phenomena; the mechanical property of the nickel-based alloy is improved, a high-strength metal structure is obtained, and the bearing capacity of the nickel-based alloy under high load is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and particularly to a method for additive manufacturing of nickel-based alloys by TIG cold welding. Background Art

[0002] Nickel-based alloys are widely used in multiple industrial fields due to their high-temperature strength, corrosion resistance, and oxidation resistance. In the aerospace field, turbine blades made of single-crystal nickel-based alloys (such as CMSX-4) can withstand temperatures above 1100 °C, significantly improving the efficiency of aeroengines; the nozzles of rocket engines use Inconel 718 alloy, and internal cooling channels are used to withstand extreme environments of 3000 °C. In the energy field, the GTD111 alloy blades of Siemens H-class gas turbines are combined with thermal barrier coatings to achieve an inlet temperature of 1600 °C and a power generation efficiency of 63%, and the lining of Alloy 690 in nuclear reactors ensures the safety of the third-generation nuclear power. In the chemical industry, the corrosion rate of Hastelloy C-276 in 98% concentrated sulfuric acid is less than 0.1 mm / year, and its service life far exceeds that of stainless steel; in ocean engineering, the Monel400 alloy tube bundle in desalination equipment extends the service life to 10 years. However, these excellent high-temperature mechanical properties also make the processing of nickel-based alloys difficult. Traditional machining methods often face problems such as rapid tool wear, large cutting forces, and low processing efficiency. Using additive manufacturing (AM) methods has become an effective solution. Additive manufacturing technology manufactures complex parts by layer-by-layer stacking of materials, which can not only reduce material waste but also provide greater design freedom and flexibility.

[0003] Nickel-based alloy additive technologies are mainly divided into directed energy deposition (DED) and powder bed fusion (PBF) technologies. These two technologies are further subdivided into electron beam powder bed melting (EB-PBF, also known as EBSM), laser powder bed melting (L-PBF, also known as SLM), laser powder deposition (LP-DED, also known as LMD), laser wire deposition (LW-DED, also known as WLAM), electron beam wire deposition (EBW-DED), and arc wire deposition (AW-DED, also known as WAAM) according to different raw materials and energy sources used; these manufacturing technologies often have disadvantages such as high manufacturing costs, low production efficiency, excessive heat input energy, and inability to be portable.

[0004] Cold welding technology is a process for metal welding at normal or low temperatures. By applying pressure, the atoms on the metal surface come into contact and diffuse with each other, thus achieving bonding. This technology has characteristics such as a small heat-affected zone, high welding quality, environmental protection and energy conservation, and is widely used in fields such as electronics, aerospace, and medical devices. The cold welder conducts arc discharge in a short time, and the interval time between welding points can be adjusted arbitrarily. Each welding point includes three processes: arc starting, arc stabilizing, and arc ending. The arc discharge time is short, and the interval time is long, so that the heat can be fully diffused. This characteristic enables no large amount of heat accumulation during part forming, reduces the heat influence of the current spot weld on the previous spot weld or layer weld, reduces heat accumulation, and can effectively control thermal deformation and thermal stress.

[0005] The publication number is CN 107008996 A, the patent number is 201710406336.1, the application date is June 2, 2017, and the patent name is "A method for metal cold welding additive manufacturing". This patent provides a method for metal cold welding additive manufacturing based on high-energy pulsed cold welding technology. Through the collaborative control of the manipulator and the positioner for the welding torch path, a dynamic wire feeder is used to synchronously feed the welding wire (diameter 0.1 - 3.0 mm). The welding wire is melted point by point by an ultra-short pulse arc (1 - 300 ms) to form a molten pool, and the substrate is forced to cool through a 1 - 10 s pulse interval to achieve layer-by-layer surfacing at normal temperature. After each layer of welding, through three-dimensional laser scanning and comparison with the model, the subsequent process parameters and path are corrected in real time, and the dynamic state of the molten pool is monitored by an infrared camera to form a closed-loop control. The core advantages of this technology lie in high forming accuracy under ultra-low heat input, the ability to manufacture complex structures without supports, and the fine-grained microstructure brought about by rapid solidification.

[0006] The additive manufacturing with pre-placed wire belongs to the same branch of arc additive technology as the above patent (patent number 201710406336.1). There are differences in the wire feeding methods between the two, but the pre-placed wire strategy still has unique advantages. By fixing the position of the welding wire in advance, the pre-placed wire avoids mechanical vibration or collaborative motion errors during the dynamic wire feeding process, and is especially suitable for the stable forming of high-melting-point or brittle materials. Since the position of the welding wire is fixed and the heat source acts continuously, the expansion range of the molten pool is more clearly physically constrained, and the predictability of the heat conduction path is stronger, which is beneficial to improving the stability of the metallurgical bonding quality. In addition, the pre-placed wire does not require a dynamic wire feeder and a complex linkage control system, simplifies the equipment structure, can significantly reduce the maintenance cost and the difficulty of process debugging, and has more efficiency advantages in batch production of regular geometric parts. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for manufacturing nickel-based alloys by using TIG cold welding additive manufacturing to overcome the disadvantages of large heat-affected zone, complex process, difficult processing, and high manufacturing cost existing in the existing methods.

[0008] To achieve the above object, the present invention is implemented by the following technical solutions.

[0009] A method for additive manufacturing of nickel-based alloys using TIG cold welding, comprising the following steps:

[0010] Step 1: Prepare the base material, multiple nickel-based alloy welding wires, a precision cold welding machine, and a TIG welding torch.

[0011] Step 2: Treat the surface of the base material to ensure that the surface of the base material is smooth, free of impurities and oxide films, and ensure that the surface roughness Ra of the base material is < 1 mm.

[0012] Step 3: Connect the positive electrode of the precision cold welding machine to the base material through the first cable, and connect the negative electrode of the precision cold welding machine to the TIG welding torch through the second cable; set the pulse current to 240 A and the pulse time to 190 ms on the precision cold welding machine.

[0013] Step 4: Construct the first nickel-based alloy deposition layer on the upper surface of the base material by arc remelting the nickel-based alloy welding wire:

[0014] 4.1 First, fix both ends of a nickel-based alloy welding wire on the base material; then, use the TIG welding torch to perform arc remelting operation from one end of the nickel-based alloy welding wire to the other end, so that a series of continuous nickel-based alloy deposition points are formed on the nickel-based alloy welding wire, and the operation of single-pass nickel-based alloy deposition is completed.

[0015] 4.2 After determining the new additive starting position, repeat the operation process of step 4.1, continuously perform multi-pass nickel-based alloy deposition operations on the upper surface of the base material until the laying of the first nickel-based alloy deposition layer is completed on the upper surface of the base material.

[0016] Step 5: Perform deposition on the upper surface of the first nickel-based alloy deposition layer by using the arc remelting process to complete the construction of the second nickel-based alloy deposition layer.

[0017] Step 6: After the welding of the second nickel-based alloy deposition layer is completed, and so on, continue to add nickel-based alloy deposition layers upward according to the design requirements, layer by layer stacking until all nickel-based alloy deposition layers are completed.

[0018] In addition, prepare an argon gas cylinder filled with argon; connect the intake port of the precision cold welding machine to the outlet port of the argon gas cylinder through the first pipeline, and connect the outlet port of the precision cold welding machine to the intake port of the TIG welding torch through the second pipeline.

[0019] The specific steps of 4.1 in the above step 4 are as follows:

[0020] (4.1.1) Clamp the base material with a welding clamp fixture to make the base material in a horizontal state.

[0021] (4.1.2) Fix both ends of a nickel-based alloy welding wire to the upper surface of the base material by spot welding;

[0022] (4.1.3) Determine the starting position of the deposition point on the nickel-based alloy welding wire, then point the muzzle of the TIG welding torch downward at this starting position, pull the trigger of the TIG welding torch, the TIG welding torch is powered on to ignite the arc, and while the arc is ignited, argon gas is ejected from the muzzle of the TIG welding torch, and the flow rate of the argon gas is 15 L / min; under the action of the high temperature of the arc, the nickel-based alloy welding wire and the base material at the deposition point are fully melted, and the argon gas can prevent the molten metal from being oxidized, and the duration of the arc is 190 ms; the arc goes out, and after the molten metal naturally cools and solidifies, a single nickel-based alloy deposition point is formed;

[0023] (4.1.4) Translate the TIG welding torch along the direction of the nickel-based alloy welding wire and continue the arc remelting operation to complete the operation of the next nickel-based alloy deposition point; operate in this way in a cycle until nickel-based alloy deposition points are formed at all the points to be processed on the nickel-based alloy welding wire; during the operation process, it is necessary to ensure that the overlap rate of two adjacent nickel-based alloy deposition points is 50% - 60%, and then the single-pass nickel-based alloy deposition is completed.

[0024] Among them, the base material is austenitic stainless steel.

[0025] The specific steps of the above step five are as follows:

[0026] 5.1 On the upper surface of the first nickel-based alloy deposition layer, first complete the single-pass nickel-based alloy deposition, specifically,

[0027] (5.1.1) Fix both ends of a nickel-based alloy welding wire to the upper surface of the first nickel-based alloy deposition layer by spot welding;

[0028] (5.1.2) Determine the starting position of the deposition point on the nickel-based alloy welding wire, then point the muzzle of the TIG welding torch downward at this starting position, pull the trigger of the TIG welding torch, the TIG welding torch is powered on to ignite the arc, and while the arc is ignited, argon gas is ejected from the muzzle of the TIG welding torch, and the flow rate of the argon gas is 15 L / min; under the action of the high temperature of the arc, the nickel-based alloy welding wire and the first nickel-based alloy deposition layer at the deposition point are fully melted, and the argon gas can prevent the molten metal from being oxidized, and the duration of the arc is 190 ms; the arc goes out, and after the molten metal naturally cools and solidifies, a single nickel-based alloy deposition point is formed;

[0029] (5.1.3) Translate the TIG torch along the direction of the nickel-based alloy wire and continue the arc remelting operation to complete the operation of the next nickel-based alloy deposition point; perform operations in this cyclic manner until nickel-based alloy deposition points are formed at all the points to be processed on the nickel-based alloy wire; during the operation process, ensure that the overlap rate of two adjacent nickel-based alloy deposition points is 50% - 60%, then the single-pass nickel-based alloy deposition is completed;

[0030] After determining the new additive manufacturing starting position, repeat the operation process in step 5.1 and continuously perform multi-pass nickel-based alloy deposition operations on the upper surface of the first nickel-based alloy deposition layer until the laying of the second nickel-based alloy deposition layer is completed on the upper surface of the first nickel-based alloy deposition layer.

[0031] The specific steps of the above step two are as follows:

[0032] 2.1 Mechanically level the surface of the substrate to ensure that the surface of the substrate is smooth and free of impurities;

[0033] 2.2 Perform pickling treatment on the surface of the substrate: First, clean the surface of the substrate with clean water; then apply pickling solution on the surface of the substrate to dissolve the oxide film on the surface of the substrate; then gently brush the surface of the substrate with a brush to remove the oxide film; finally, rinse the surface of the substrate with clean water;

[0034] 2.3 Perform activation treatment on the surface of the substrate: Immerse the substrate completely in the surface activator, take it out after soaking for 1 - 2 minutes, and the surface activator can completely remove the residual oxide film on the surface of the substrate;

[0035] 2.4 Surface roughness test: Observe the surface roughness of the substrate using a laser confocal microscope, and require that the surface roughness Ra of the substrate < 1mm; if the surface roughness Ra of the substrate > 1mm, then it is necessary to return to step 2.1 for continuous treatment;

[0036] Among them, the pickling solution is composed of a nitric acid solution and a hydrofluoric acid solution mixed in a volume ratio of 3:1; the mass percentage concentration of the nitric acid solution is 10%, and the mass percentage concentration of the hydrofluoric acid solution is 10%.

[0037] Among them, the surface activator is a hydrochloric acid solution, and the mass percentage concentration of the hydrochloric acid solution is 10%.

[0038] The advantages of the present invention are:

[0039] 1. High-quality additive manufacturing. After additive manufacturing, the nickel-based alloy deposition layer has a smooth surface, no obvious cracks, good density, tight interlayer bonding, and no delamination or detachment phenomenon. In addition, the smooth surface of the nickel-based alloy deposition layer reduces the difficulty and cost of subsequent processing.

[0040] 2. Precise process control: The TIG cold welding additive manufacturing technology can achieve low and uniform heat input by precisely controlling the heat input and deposition rate, thereby reducing the thermal deformation and stress of the nickel-based alloy deposition layer. The process adjustment is flexible and can provide higher precision during the additive manufacturing process, especially suitable for small-scale stacking operations. Compared with other technologies, the TIG cold welding additive process has higher precision in controlling the molten pool, closer interlayer bonding, significantly reducing the cost of subsequent processing, and is suitable for strict precision manufacturing applications.

[0041] 3. Small heat-affected zone: Due to its stable arc and controlled heat input, the TIG cold welding additive process can significantly reduce the heat-affected zone (HAZ). The lower heat input reduces the thermal expansion and contraction of the material, effectively reducing the risk of deformation. At the same time, the small heat-affected zone avoids grain coarsening, helping to maintain its mechanical and corrosion resistance properties.

[0042] 4. High mechanical properties: The TIG cold welding additive manufacturing technology can precisely control the heat input and cooling time of the molten pool during the deposition process. The surface of the nickel-based alloy deposition layer is flat and free of crack defects, which helps to improve the mechanical properties of the nickel-based alloy. It can obtain a high-strength metal structure and enhance the load-bearing capacity of the nickel-based alloy under high loads.

[0043] 5. Cost savings: The TIG cold welding additive manufacturing is a process of layer-by-layer deposition. Compared with traditional manufacturing methods, it has significant advantages in material savings. By precisely controlling the deposition of nickel-based alloys, the waste of excess nickel-based alloys can be avoided. Description of the Drawings

[0044] Figure 1 It is a schematic connection structure diagram of the precision cold welding machine, TIG welding torch, argon gas cylinder and substrate in the present invention;

[0045] Figure 2 It is the appearance morphology diagram of the first nickel-based alloy deposition layer completed on the substrate through the arc remelting process in step four of the present invention;

[0046] Figure 3 It is the appearance morphology diagram of all nickel-based alloy deposition layers completed on the substrate through the arc remelting process in step six of the present invention;

[0047] Figure 4 For Figure 3 front view;

[0048] Figure 5 For Figure 4 top view;

[0049] Figure 6 For Figure 4 right view;

[0050] Figure 7is Figure 4 Cross-sectional view A-A of; ( Figure 7 In, area B is the interface area where the substrate meets the nickel-based alloy, and area E is the nickel-based alloy)

[0051] Figure 8 is to use a scanning electron microscope and an energy dispersive spectrometer to magnify Figure 7 area B of by 500 times to obtain a schematic diagram of the microstructure;

[0052] Figure 9 is to use a scanning electron microscope and an energy dispersive spectrometer to magnify Figure 7 area E of by 1000 times to obtain a schematic diagram of the microstructure;

[0053] Figure 10 is to use an energy dispersive spectrometer for area scanning of Figure 7 area B of to obtain a schematic diagram of the distribution of carbon elements;

[0054] Figure 11 is to use an energy dispersive spectrometer for area scanning of Figure 7 area B of to obtain a schematic diagram of the distribution of chromium elements;

[0055] Figure 12 is to use an energy dispersive spectrometer for area scanning of Figure 7 area B of to obtain a schematic diagram of the distribution of iron elements;

[0056] Figure 13 is to use an energy dispersive spectrometer for area scanning of Figure 7 area B of to obtain a schematic diagram of the distribution of nickel elements;

[0057] Figure 14 is to use an energy dispersive spectrometer for area scanning of Figure 7 area B of to obtain a schematic diagram of the distribution of niobium elements;

[0058] Figure 15 is to use an energy dispersive spectrometer for area scanning of Figure 7 area B of to obtain a schematic diagram of the distribution of molybdenum elements;

[0059] Figure 16 is to use an energy dispersive spectrometer for line scanning of Figure 7 area E of to obtain a distribution curve of carbon elements; ( Figure 16 In, the length of the abscissa is Figure 9 the length of line segment DF in

[0060] Figure 17 is to use an energy dispersive spectrometer for line scanning of Figure 7 area E of to obtain a distribution curve of chromium elements; ( Figure 17 In, the length of the abscissa is Figure 9 the length of line segment DF in

[0061] Figure 18 To obtain a distribution curve of iron element by using line scanning of an energy spectrometer in the E part;( Figure 7 The length of the abscissa in Figure 18 is the length of Figure 9 line segment DF)

[0062] Figure 19 To obtain a distribution curve of nickel element by using line scanning of an energy spectrometer in the E part;( Figure 7 The length of the abscissa in Figure 19 is the length of Figure 9 line segment DF)

[0063] Figure 20 To obtain a distribution curve of niobium element by using line scanning of an energy spectrometer in the E part;( Figure 7 The length of the abscissa in Figure 20 is the length of Figure 9 line segment DF)

[0064] Figure 21 To obtain a distribution curve of molybdenum element by using line scanning of an energy spectrometer in the E part;( Figure 7 The length of the abscissa in Figure 21 is the length of Figure 9 line segment DF)

[0065] In the figure, 1. Substrate, 2. Nickel-based alloy welding wire, 3. Precision cold welding machine, 4. TIG welding torch, 5. First cable, 6. Second cable, 7. Argon gas cylinder, 8. First pipeline, 9. Second pipeline, 10. First nickel-based alloy deposition layer, 11. All nickel-based alloy deposition layers, 12. Nickel-based alloy. Specific embodiments

[0066] The following will further elaborate on the specific embodiments of the present invention with reference to the accompanying drawings, so that the technical solutions of the present invention are easier to understand and master. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0067] The present invention provides a method for manufacturing nickel-based alloys by using TIG cold welding additive manufacturing, and the method includes the following steps:

[0068] Step 1: Prepare a substrate 1, multiple nickel-based alloy welding wires 2, a precision cold welding machine 3, a TIG welding torch 4, and an argon gas cylinder 7 filled with argon; among them, the substrate 1 is austenitic stainless steel.

[0069] Step 2: Treat the surface of the substrate 1:

[0070] 2.1 Mechanically level the surface of substrate 1, and polish it successively with 400#, 800#, 1200#, 1500# and 2000# sandpapers to ensure that the surface of substrate 1 is smooth and free of impurities;

[0071] 2.2 Pickle the surface of substrate 1: First, clean the surface of substrate 1 with clean water; then apply pickling solution on the surface of substrate 1 to dissolve the oxide film on the surface of substrate 1; then gently brush the surface of substrate 1 with a brush to remove the oxide film; finally, rinse the surface of substrate 1 with clean water; among them, the pickling solution is composed of nitric acid solution and hydrofluoric acid solution mixed in a volume ratio of 3:1; the mass percentage concentration of the nitric acid solution is 10%, and the mass percentage concentration of the hydrofluoric acid solution is 10%;

[0072] 2.3 Activate the surface of substrate 1: Immerse substrate 1 completely in the surface activator, take it out after soaking for 1 - 2 minutes, and the surface activator can completely remove the residual oxide film on the surface of substrate 1; among them, the surface activator is hydrochloric acid solution, and the mass percentage concentration of the hydrochloric acid solution is 10%;

[0073] 2.4 Surface roughness test: Use a laser confocal microscope to observe the surface roughness of substrate 1, and require that the surface roughness Ra of substrate 1 < 1mm; if the surface roughness Ra of substrate 1 > 1mm, it is necessary to return to step 2.1 for further treatment.

[0074] Step three, as Figure 1 shown, the positive electrode of the precision cold welding machine 3 is connected to the substrate 1 through the first cable 5, and the negative electrode of the precision cold welding machine 3 is connected to the TIG welding torch 4 through the second cable 6; the air inlet of the precision cold welding machine 3 is connected to the air outlet of the argon gas cylinder 7 through the first pipeline 8, and the air outlet of the precision cold welding machine 3 is connected to the air inlet of the TIG welding torch 4 through the second pipeline 9; and a pulse current of 240A and a pulse time of 190ms are set on the precision cold welding machine 3.

[0075] Step four, construct the first nickel-based alloy deposition layer 10 on the upper surface of substrate 1 by arc remelting nickel-based alloy welding wire 2:

[0076] 4.1 On the upper surface of substrate 1, first complete single-pass nickel-based alloy deposition. Specifically,

[0077] (4.1.1) Clamp substrate 1 with a welding clamp fixture to make substrate 1 in a horizontal state;

[0078] (4.1.2) Fix both ends of a nickel-based alloy welding wire 2 on the upper surface of substrate 1 by spot welding;

[0079] (4.1.3) Determine the starting position of the deposition point on the nickel-based alloy wire 2. Then, point the muzzle of the TIG welding torch 4 downward at this starting position, so that the tungsten electrode at the muzzle of the TIG welding torch 4 is 2 mm above the nickel-based alloy wire 2, and ensure that the tungsten electrode at the muzzle is perpendicular to the nickel-based alloy wire 2. Then, pull the trigger of the TIG welding torch 4 to energize the TIG welding torch 4 to ignite the arc. While igniting the arc, argon gas is ejected from the muzzle of the TIG welding torch 4, and the flow rate of the argon gas is 15 L / min. Under the action of the high temperature of the arc, the nickel-based alloy wire 2 and the base material 1 at the deposition point are fully melted, and the argon gas can prevent the molten metal from being oxidized. The duration of the arc is 190 ms. After the arc is extinguished, wait for the molten metal to cool and solidify naturally, and then a single nickel-based alloy deposition point is formed.

[0080] (4.1.4) Move the TIG welding torch 4 2.5 mm to the left or right along the direction of the nickel-based alloy wire 2, and continue the arc remelting operation to complete the operation of the next nickel-based alloy deposition point. Operate in this cyclic manner until nickel-based alloy deposition points are formed at all the points to be processed on the nickel-based alloy wire 2. Each nickel-based alloy deposition point is circular, with a diameter of 4.5 - 5 mm. During the operation process, it is necessary to ensure that the overlapping rate of two adjacent nickel-based alloy deposition points is between 50% and 60%, and then the single-pass nickel-based alloy deposition is completed.

[0081] After determining the new additive manufacturing starting position, repeat the operation process of step 4.1, and continuously carry out multi-pass nickel-based alloy deposition operations on the upper surface of the base material 1 until the laying of the first nickel-based alloy deposition layer 10 is completed on the upper surface of the base material 1. The appearance of the first nickel-based alloy deposition layer 10 is as Figure 2 shown. It can be seen that the first nickel-based alloy deposition layer 10 is composed of multiple closely arranged nickel-based alloy depositions. The surface of the nickel-based alloy formed after deposition is smooth, without obvious defects, and has high forming quality.

[0082] Step Five, on the upper surface of the first nickel-based alloy deposition layer 10, use the arc remelting process for deposition to complete the construction of the second nickel-based alloy deposition layer:

[0083] 5.1 On the upper surface of the first nickel-based alloy deposition layer 10, first complete a single-pass nickel-based alloy deposition. Specifically,

[0084] (5.1.1) Fix both ends of a nickel-based alloy wire 2 on the upper surface of the first nickel-based alloy deposition layer 10 by spot welding.

[0085] (5.1.2) Determine the starting position of the deposition point on the nickel-based alloy wire 2. Then, aim the muzzle of the TIG welding torch 4 downward at this starting position, making the tungsten electrode at the muzzle of the TIG welding torch 4 located 2 mm above the nickel-based alloy wire 2, and ensuring that the tungsten electrode at the muzzle is perpendicular to the nickel-based alloy wire 2. Then, pull the trigger of the TIG welding torch 4 to energize and ignite the arc. While igniting the arc, argon gas is ejected from the muzzle of the TIG welding torch 4, and the flow rate of the argon gas is 15 L / min. Under the action of the high temperature of the arc, the nickel-based alloy wire 2 and the first nickel-based alloy deposition layer 10 at the deposition point are fully melted. The argon gas can prevent the molten metal from being oxidized. The duration of the arc is 190 ms. After the arc is extinguished, wait for the molten metal to cool and solidify naturally, and then a single nickel-based alloy deposition point is formed.

[0086] (5.1.3) Along the direction of the nickel-based alloy wire 2, translate the TIG welding torch 4 2.5 mm to the left or right, and continue the arc remelting operation to complete the operation of the next nickel-based alloy deposition point. Operate in this cyclic manner until nickel-based alloy deposition points are formed at all the points to be processed on the nickel-based alloy wire 2. Each nickel-based alloy deposition point is circular, with a diameter of 4.5 - 5 mm. During the operation, it is necessary to ensure that the overlapping rate of two adjacent nickel-based alloy deposition points is 50% - 60%, and then the single-pass nickel-based alloy deposition is completed.

[0087] After determining the new additive manufacturing starting position, repeat the operation process of step 5.1, and continuously perform multi-pass nickel-based alloy deposition operations on the upper surface of the first nickel-based alloy deposition layer 10 until the laying of the second nickel-based alloy deposition layer is completed on the upper surface of the first nickel-based alloy deposition layer 10.

[0088] Step Six, after the second nickel-based alloy deposition layer is welded, and so on, continue to add nickel-based alloy deposition layers upward according to the design requirements, layer by layer stacking, until all the nickel-based alloy deposition layers 11 are completed, as Figure 3 shown.

[0089] In the above steps (4.1.3) and (5.1.2), while the TIG welding torch 4 is energized to ignite the arc, argon gas is ejected from the muzzle of the TIG welding torch 4 to provide atmosphere protection for the molten metal. The argon gas protection atmosphere can effectively avoid metal oxidation during the additive manufacturing process, improve the strength and toughness of the nickel-based alloy 12. At the same time, due to the controlled heat input, the risk of stress concentration and hot cracks is reduced, ensuring that the nickel-based alloy 12 has high mechanical properties.

[0090] In the above step two, the nitric acid solution was directly purchased from the market. Its manufacturer is: Fuzhou Weberkang Biotechnology Co., Ltd., and the mass percentage concentration of the nitric acid solution is 10%; the hydrofluoric acid solution was directly purchased from the market. Its manufacturer is: Haibiao Technology Co., Ltd., and the mass percentage concentration of the hydrofluoric acid solution is 10%; the hydrochloric acid solution was directly purchased from the market. Its manufacturer is: Beijing Zhongke Erhuan Technology Co., Ltd., and the mass percentage concentration of the hydrochloric acid solution is 10%.

[0091] The nickel-based alloy welding wire 2 used in the present invention has a model: ErNiCrMo-3-1.6mm, a manufacturer: Shanghai Hanying Special Welding Materials Co., Ltd., and its diameter is 1.6mm. The precision cold welding machine 3 used in the present invention has a brand: ANDELI, a model: WS-250G, and a manufacturer: Andeli Group Co., Ltd. The TIG welding torch 4 used in the present invention has a brand: ANDELI, a model: WP-9, and a manufacturer: Andeli Group Co., Ltd.

[0092] In step six of the process of the present invention, after all layers of nickel-based alloy deposition are completed on the substrate 1, the final appearance morphology diagram of the nickel-based alloy is as Figure 3 shown Figure 4 is Figure 3 the front view of Figure 5 is Figure 4 the top view of Figure 6 is Figure 4 the right view of; from Figure 3 , Figure 4 , Figure 5 and Figure 6 it can be seen that: all the nickel-based alloy deposition layers 11 after additive manufacturing are smooth on the surface, without obvious cracks, with good density, close layer-to-layer bonding, and no delamination or detachment phenomenon.

[0093] Figure 7 is Figure 4 the A-A cross-sectional view of, and from Figure 7 it can be seen that: the interface at the junction of the substrate 1 and the nickel-based alloy 12 is tightly connected by fusion, without obvious cracks, pores and other defects, forming a reliable metallurgical bond. A small number of circular pores can be seen between the deposition layers of the nickel-based alloy 12 by additive manufacturing, and they are distributed in a dispersed manner; such pores are caused by the insufficient escape of gas during the additive manufacturing process.

[0094] Figure 8 is to use a scanning electron microscope and an energy spectrometer to magnify the B part area of Figure 7 (the B part area of Figure 7 is the interface area at the junction of the substrate 1 and the nickel-based alloy 12) by 500 times to obtain a schematic diagram of the microstructure; from Figure 8It can be seen that the nickel-based alloy 12 is deposited on the surface of the substrate 1 by TIG cold welding additive manufacturing technology, and the microstructure of the nickel-based alloy 12 is uniform. In the interface region between the substrate 1 and the nickel-based alloy 12, there is a clear fusion boundary; moreover, the interfacial metallurgical bonding at the junction of the substrate 1 and the nickel-based alloy 12 is good, without defects such as cracks and delamination.

[0095] Figure 9 To utilize the scanning electron microscope and energy spectrometer, the Figure 7 E part area of Figure 7 the E part area is the nickel-based alloy 12) is magnified 1000 times to obtain a schematic diagram of the microstructure; from Figure 9 it can be seen that the structure of the nickel-based alloy 12 presents a typical γ-phase structure, with fine and uniformly distributed grains, high density, and clear grain boundaries.

[0096] From Figure 10 it can be seen that carbon elements are evenly distributed on both sides of the substrate 1 and the nickel-based alloy 12, and the overall content is low.

[0097] From Figure 11 it can be seen that chromium elements exist on both sides of the substrate 1 and the nickel-based alloy 12; at the interface where the substrate 1 and the nickel-based alloy 12 meet, a gradient is formed due to the mutual diffusion of chromium elements; moreover, the chromium content in the nickel-based alloy 12 is usually lower than that in the substrate 1.

[0098] From Figure 12 it can be seen that the iron element content in the substrate 1 is the highest; the iron element diffuses from the junction interface region to the nickel-based alloy 12, and the iron content gradually decreases, forming a gradient.

[0099] From Figure 13 it can be seen that the nickel element content in the nickel-based alloy 12 is the highest, and the nickel element diffuses toward the substrate 1 side; away from the junction interface region, the nickel content in the substrate 1 gradually decreases.

[0100] From Figure 14 it can be seen that niobium elements are distributed as strengthening elements in the nickel-based alloy 12, and the content of niobium elements in the nickel-based alloy 12 is significantly higher than that in the substrate 1.

[0101] From Figure 15 it can be seen that molybdenum elements are distributed as strengthening elements in the nickel-based alloy 12, and the content of molybdenum elements in the nickel-based alloy 12 is significantly higher than that in the substrate 1.

[0102] From Figure 16It can be seen that the X-ray intensity of carbon element (C) fluctuates regularly within the range of 0–32 μm in length. Although there are local fluctuations, the overall distribution is relatively continuous, and no extremely enriched or depleted regions appear. This reflects that the material has achieved macroscopic uniformity of composition and controllability of microstructure through process optimization, providing an important guarantee for the high-temperature stability and mechanical properties of nickel-based alloy 12.

[0103] It can be seen from Figure 17 It can be seen that the X-ray intensity of chromium element (Cr) shows dynamic fluctuations within the range of 0–32 μm in length. The overall signal intensity is at a medium level and is continuously distributed, without abnormal peaks or cliff-like drops. This reflects the macroscopic coordination and microscopic controllability of the material composition design. The distribution of chromium not only avoids the brittleness risk caused by local excess but also enhances the oxidation resistance, corrosion resistance, and high-temperature stability of the alloy through the formation of grain boundary strengthening phases.

[0104] It can be seen from Figure 18 It can be seen that the X-ray intensity of iron element (Fe) shows significant regular fluctuations within the range of 0–32 μm in length, and the overall signal distribution is continuous. Although the intensity change range is large, its dynamic balance characteristics reflect the macroscopic uniformity of the material composition and the ability to control the microstructure.

[0105] It can be seen from Figure 19 It can be seen that the X-ray intensity of nickel element (Ni) shows significant periodic fluctuations within the range of 0–32 μm in length, and the overall signal intensity distribution is continuous without sudden abnormal values. This periodic fluctuation may correspond to the dynamic redistribution of nickel element at grain boundaries. Although the intensity change amplitude is large, its regular characteristics indicate that the distribution of nickel has macroscopic uniformity and microstructure controllability.

[0106] It can be seen from Figure 20 It can be seen that the X-ray intensity of niobium element (Nb) shows significant periodic fluctuations within the range of 0–32 μm in length, and the overall signal distribution is continuous. This periodic fluctuation may correspond to the regular segregation of niobium element at grain boundaries. Although the intensity change amplitude is large, its fluctuation regularity and signal continuity indicate that the distribution of niobium has both macroscopic uniformity and the ability to control the microstructure.

[0107] It can be seen from Figure 21 It can be seen that the X-ray intensity of molybdenum element (Mo) shows significant periodic fluctuations within the range of 0–32 μm in length, and the overall signal distribution is continuous. The peak intensity can reach about 3000 cps, and the valley value is maintained at about 600 cps, forming a regular peak-valley alternating pattern. This fluctuation may correspond to the dynamic segregation of molybdenum element at grain boundaries or the uniform dispersion precipitation of nanoscale carbides.

Claims

1. A method for manufacturing a nickel-based alloy by TIG cold welding, characterized in that: The following steps are involved: Step 1: prepare a substrate (1), a plurality of nickel-based alloy welding wires (2), a precision cold welding machine (3) and a TIG welding gun (4); Step 2: Treat the surface of the substrate (1) to ensure that the surface of the substrate (1) is smooth, free of impurities and oxide film, and that the surface roughness Ra of the substrate (1) is less than 1 mm; Step 3: The positive electrode of the precision cold welding machine (3) is connected to the substrate (1) via the first cable (5), and the negative electrode of the precision cold welding machine (3) is connected to the TIG welding gun (4) via the second cable (6); a pulse current of 240A and a pulse time of 190ms are set on the precision cold welding machine (3); Step 4: constructing a first nickel-based alloy deposition layer (10) on the upper surface of the substrate (1) by arc remelting the nickel-based alloy welding wire (2): 4.1 First, the two ends of a nickel-based alloy welding wire (2) are fixed on a substrate (1); then, a TIG welding gun (4) is used to perform an arc remelting operation from one end to the other end of the nickel-based alloy welding wire (2), so that a series of continuous nickel-based alloy deposition points are formed on the nickel-based alloy welding wire (2), thereby completing a single-pass nickel-based alloy deposition operation; 4.2 After determining the new starting position of the additive process, repeat the operation process of step 4.1, and continue to perform multiple nickel-based alloy deposition operations on the upper surface of the substrate (1) until the first nickel-based alloy deposition layer (10) is laid on the upper surface of the substrate (1); Step 5: depositing on the upper surface of the first nickel-based alloy deposited layer (10) by using an arc remelting process to complete the construction of a second nickel-based alloy deposited layer; Step 6: After the second nickel-based alloy deposition layer is welded, the nickel-based alloy deposition layer is continuously added upwards according to the design requirements, layer by layer, until all nickel-based alloy deposition layers (11) are completed.

2. The method for additively manufacturing nickel-based alloys by TIG cold welding according to claim 1, characterized in that: An argon gas tank (7) filled with argon is prepared; the air inlet of the precision cold welding machine (3) is connected to the air outlet of the argon gas tank (7) via a first pipeline (8), and the air outlet of the precision cold welding machine (3) is connected to the air inlet of the TIG welding gun (4) via a second pipeline (9).

3. The method for manufacturing nickel-based alloy by TIG cold welding according to claim 2, characterized in that: The specific steps of 4.1 in the step 4 are: (4.1.1) Clamp the substrate (1) with a welding clamp so that the substrate (1) is in a horizontal state; (4.1.2) fixing both ends of a nickel-based alloy welding wire (2) to the upper surface of the substrate (1) by spot welding; (4.1.3) The starting position of the deposition point is determined on the nickel-based alloy welding wire (2), and then the muzzle of the TIG welding gun (4) is pointed downward at the starting position, and the switch of the TIG welding gun (4) is pressed, and the TIG welding gun (4) is powered on to ignite the arc. At the same time, argon gas is ejected from the muzzle of the TIG welding gun (4); under the high temperature of the arc, the nickel-based alloy welding wire (2) and the substrate (1) at the deposition point are fully melted, and the argon gas can prevent the molten metal from being oxidized. The arc lasts for 190ms; the arc is extinguished, and after the molten metal is naturally cooled and solidified, a single nickel-based alloy deposition point is formed; (4.1.4) The TIG welding gun (4) is translated along the direction of the nickel-based alloy welding wire (2) to continue the arc remelting operation and complete the operation of the next nickel-based alloy deposition point; the operation is repeated in this manner until all the points to be processed on the nickel-based alloy welding wire (2) form nickel-based alloy deposition points; during the operation, it is necessary to ensure that the overlap rate of two adjacent nickel-based alloy deposition points is 50% to 60%, thereby completing a single-pass nickel-based alloy deposition.

4. The method for additively manufacturing nickel-based alloys by TIG cold welding according to claim 3, characterized in that: In step 4 (4.1.3), the flow rate of argon gas ejected from the muzzle of the TIG welding gun (4) is 15 L / min.

5. The method for additively manufacturing nickel-based alloys by TIG cold welding according to claim 3, characterized in that: The substrate (1) is austenitic stainless steel.

6. The method for manufacturing nickel-based alloy by TIG cold welding according to claim 2, characterized in that: The specific steps of step five are: 5.1 On the upper surface of the first nickel-based alloy deposition layer (10), a single-pass nickel-based alloy deposition is first performed, specifically, (5.1.1) fixing two ends of a nickel-based alloy welding wire (2) to the upper surface of the first nickel-based alloy deposition layer (10) by spot welding; (5.1.2) The starting position of the deposition point is determined on the nickel-based alloy welding wire (2), and then the muzzle of the TIG welding gun (4) is pointed downward at the starting position, and the switch of the TIG welding gun (4) is pressed, and the TIG welding gun (4) is powered on to ignite the arc. While the arc is ignited, argon gas is ejected from the muzzle of the TIG welding gun (4); under the high temperature of the arc, the nickel-based alloy welding wire (2) and the first nickel-based alloy deposition layer (10) at the deposition point are fully melted, and the argon gas can prevent the molten metal from being oxidized. The arc duration is 190ms; the arc is extinguished, and after the molten metal is naturally cooled and solidified, a single nickel-based alloy deposition point is formed; (5.1.3) The TIG welding gun (4) is moved horizontally along the direction of the nickel-based alloy welding wire (2) to continue the arc remelting operation and complete the operation of the next nickel-based alloy deposition point; the operation is repeated in this manner until all the points to be processed on the nickel-based alloy welding wire (2) form nickel-based alloy deposition points; during the operation, the overlap rate of two adjacent nickel-based alloy deposition points must be ensured to be 50% to 60%, so as to complete the single-pass nickel-based alloy deposition; 5.2 After determining the new starting position for additive manufacturing, repeat the operation process of step 5.1, and continue to perform multiple nickel-based alloy deposition operations on the upper surface of the first nickel-based alloy deposition layer (10) until the second nickel-based alloy deposition layer is completed on the upper surface of the first nickel-based alloy deposition layer (10).

7. The method for additively manufacturing nickel-based alloys by TIG cold welding according to claim 6, characterized in that: In step 5 (5.1.2), the flow rate of argon gas ejected from the muzzle of the TIG welding gun (4) is 15 L / min.

8. The method for additively manufacturing nickel-based alloys by TIG cold welding according to claim 1, characterized in that: The specific steps of step 2 are: 2.1 Mechanically leveling the surface of the substrate (1) to ensure that the surface of the substrate (1) is smooth and free of impurities; 2.2 Perform pickling treatment on the surface of the substrate (1): First, clean the surface of the substrate (1) with clean water; then apply pickling liquid on the surface of the substrate (1) to dissolve the oxide film on the surface of the substrate (1); then gently scrub the surface of the substrate (1) with a brush to remove the oxide film; finally, rinse the surface of the substrate (1) with clean water; 2.3 Activate the surface of the substrate (1): completely immerse the substrate (1) in a surfactant for 1 to 2 minutes and then take it out. The surfactant can completely remove the oxide film remaining on the surface of the substrate (1); 2.4 Surface roughness test: Use a laser confocal microscope to observe the surface roughness of the substrate (1), and the surface roughness Ra of the substrate (1) is required to be less than 1 mm; if the surface roughness Ra of the substrate (1) is greater than 1 mm, it is necessary to return to step 2.1 to continue processing; The substrate (1) is austenitic stainless steel.

9. The method for additively manufacturing nickel-based alloys by TIG cold welding according to claim 8, characterized in that: In 2.2 of step 2, the pickling solution is formed by mixing a nitric acid solution and a hydrofluoric acid solution in a volume ratio of 3:1; wherein the mass percentage concentration of the nitric acid solution is 10%, and the mass percentage concentration of the hydrofluoric acid solution is 10%.

10. The method for additively manufacturing nickel-based alloys by TIG cold welding according to claim 8, characterized in that: In 2.3 of step 2, the surfactant is a hydrochloric acid solution, and the mass percentage concentration of the hydrochloric acid solution is 10%.

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