A plasma thermal spray apparatus for tungsten copper alloy weld joints

Abstract

The application discloses a plasma thermal spraying device for tungsten-copper alloy welding joints and belongs to the technical field of plasma spraying, and comprises a wear-resistant component, which comprises a spraying device body, an internal part of the spraying device body is provided with a wear-resistant layer for resisting powder scouring and high-temperature corrosion, a gradient composite transition layer is arranged between the wear-resistant layer and the spraying device body, and an elastic buffer layer for absorbing expansion difference is arranged between the gradient composite transition layer and the spraying device body. A whisker composite ceramic wear-resistant layer is arranged on the inner wall of the spraying head, the hardness of the whisker composite ceramic wear-resistant layer is much higher than that of conventional metals, copper-tungsten alloy and other alloy materials, and the density of the whisker composite ceramic wear-resistant layer is significantly improved after plasma spraying and laser remelting, the probability of embedding powder particles into a surface layer is reduced, the ceramic has excellent chemical stability and does not react with plasma gas and high-temperature oxides, oxidation and corrosion of the inner wall of the spraying head are avoided, the wear resistance of the inner wall of the spraying head is significantly improved, and powder feeding and spraying precision are ensured.

Description

Technical Field

[0001] This application relates to the field of plasma spraying technology, and more specifically, to a plasma thermal spraying apparatus for tungsten-copper alloy welding heads. Background Technology

[0002] Tungsten-copper alloys, with their excellent thermal conductivity (150-200 W / m·K), arc erosion resistance, and good mechanical compatibility, have become core materials for automotive welding electrodes, semiconductor packaging welding heads, and precision welding components in aerospace. However, tungsten-copper alloys themselves have low surface hardness (HV≤300), poor high-temperature wear resistance (easily oxidized at >500℃), and weak resistance to powder erosion. Under high-frequency welding conditions (≥500 welding cycles per day), the surface is prone to wear pitting and oxidation corrosion, leading to a shortened service life of the welding head (normal lifespan). The welding time is only 300-500 hours, and the welding accuracy gradually decreases with surface damage, which seriously affects the consistency of workpiece welding quality. Therefore, plasma thermal spraying technology has become the core means of surface strengthening of tungsten copper alloy welding heads. By heating wear-resistant powder (such as WC-Co, whisker composite ceramics) to a molten state and spraying it at high speed onto the surface of the welding head, a dense functional coating (thickness 50-500μm) is formed, which can increase the surface hardness to HV1500-2200 and extend the wear resistance life by 5-10 times, while retaining the high thermal conductivity of the tungsten copper matrix.

[0003] The inner wall of the nozzle in existing plasma spraying devices is mostly made of copper alloy or ordinary tungsten copper, which has a hardness far lower than the erosion strength of high-speed sprayed powder. After long-term use, the inner wall is prone to wear and pitting, and the diameter will increase. At the same time, the working environment temperature of the nozzle is as high as 800-1200℃, and it is exposed to plasma gas and high-temperature oxidation products of welding head. The inner wall of the plasma spraying device nozzle is prone to oxidation and corrosion, which leads to an increase in the roughness of the inner wall. In addition, the flame carries the powder to accelerate at the powder outlet, which will cause the powder outlet to gradually expand, causing the powder delivery trajectory to deviate, the powder delivery amount to fluctuate, and ultimately the coating thickness deviation.

[0004] In view of this, we propose a plasma thermal spraying device for tungsten-copper alloy welding heads. Summary of the Invention

[0005] Technical problem to be solved: The purpose of this application is to provide a plasma thermal spraying device for tungsten-copper alloy welding heads, which solves the technical problems mentioned in the background art.

[0006] Technical Solution: This application provides a plasma thermal spraying device for tungsten-copper alloy welding heads, including a filter component, which includes a wear-resistant component, and a spraying device body. The spraying device body has an internal wear-resistant layer to resist powder erosion and high-temperature corrosion. A gradient composite transition layer is provided between the wear-resistant layer and the spraying device body. An elastic buffer layer for absorbing expansion differences is provided between the gradient composite transition layer and the spraying device body. A tungsten-copper gradient layer is provided between the elastic buffer layer and the spraying device body. The spraying device body has a powder feeding channel for conveying coating dust. The powder feeding channel has a wear-resistant component to increase its service life. A spraying outlet is provided within the wear-resistant layer. A first chute is provided within the wear-resistant layer. A honeycomb-shaped elastic element is provided inside the gradient composite transition layer.

[0007] The compensation component includes a compensation assembly disposed in a first groove, the compensation assembly being provided with a flexible compensation bushing for compensating for the wear portion of the wear-resistant assembly, a fixing assembly for fixing the compensation assembly being disposed within the wear-resistant layer, and a guiding assembly for guiding the filling fluid being disposed inside the wear-resistant layer.

[0008] By adopting the above technical solution, the wear-resistant layer can be added to increase the wear resistance of the inner wall of the elastic buffer layer.

[0009] As an optional solution to the technical solution of this application, the main body of the spraying device includes a robotic arm, on which a spray head is detachably connected. The spray head has a rear electrode and a front electrode inside, and a medium channel. A cooling inlet is provided on the side of the robotic arm, a cooling groove is provided inside the spray head, a cooling outlet is provided on the top of the spray head, and a rotating clamp is provided on the side of the robotic arm.

[0010] As an optional solution to the technical solution of this application, the cooling inlet is connected to the cooling outlet through a cooling tank, the wear-resistant layer is made of low thermal conductivity whisker composite ceramic material, the elastic buffer layer has a number of honeycomb-shaped unit elastic elements evenly distributed inside, the honeycomb-shaped unit elastic elements are made of nickel-based superalloy material, the inner wall material of the powder feeding channel is the same as that of the wear-resistant layer, the wear-resistant layer is located on the side of the front electrode away from the rear electrode, and the spraying outlet is located on the side of the wear-resistant layer away from the front electrode.

[0011] By adopting the above technical solution, setting a gradient composite transition layer, an elastic buffer layer, and a tungsten-copper gradient layer can ensure the stability between the wear-resistant layer and the nozzle substrate.

[0012] As an optional solution to the technical solution of this application, the wear-resistant component includes a fixed seat disposed on the side of the nozzle, a wear-resistant head fixedly connected to the fixed seat, a groove being formed on the side of the wear-resistant head near the first slide groove, the wear-resistant head being made of a low thermal conductivity insulating material, the side of the fixed seat near the nozzle penetrating the powder feeding channel, the wear-resistant head being located inside the powder feeding channel, and the side of the fixed seat away from the wear-resistant head being detachably connected to the side of the nozzle.

[0013] By adopting the above technical solution, the wear-resistant head can protect the inner wall of the powder feeding channel and prevent the powder outlet from expanding due to wear, which could lead to spraying disorder.

[0014] As an optional solution to the technical solution of this application, the compensation component includes a compensation plate slidably connected inside the first chute, the compensation plate having an infusion channel inside, the infusion channel having a sealing plug inside, the compensation plate having a plurality of outlet holes evenly distributed at the end away from the sealing plug, the compensation plate having a second chute on the side near the spray outlet, the second chute having a sliding plate slidably connected inside, the sliding plate having a diaphragm fixedly connected on the side near the outlet hole, the compensation plate having two fixing holes, and the compensation plate having two conical grooves on the side near the gradient composite transition layer.

[0015] As an optional solution to the technical solution of this application, the compensation plate is made of heat-insulating material, the conical groove is connected to the infusion channel, the two fixing holes are located on both sides of the infusion channel, the size of the compensation plate is adapted to the size of the first sliding groove, the first sliding groove extends through the inner wall of the wear-resistant layer to the interior of the powder feeding channel, the flexible compensation bushing is detachably connected to the slide plate and the surface of the compensation plate, the side of the compensation plate away from the liquid outlet abuts against the surface of the wear-resistant head, and the flexible compensation bushing is made of carbon fiber material.

[0016] By adopting the above technical solution, the wear-resistant layer of carbon fiber material can simultaneously possess both flexibility and wear resistance, further preventing powder from causing wear on the powder feeding channel.

[0017] As an optional solution to the technical solution of this application, the fixing component includes a third sliding groove formed inside the wear-resistant layer, a slider is slidably connected inside the third sliding groove, a fixing rod is fixedly connected to the top of the slider, a first elastic element is provided on the side of the slider away from the fixing rod, and a lever is fixedly connected to the slider.

[0018] As an optional solution to the technical solution of this application, the dial plate extends through the inner wall of the third slide groove to the side of the wear-resistant layer away from the front electrode, the slider is elastically connected to the inner wall of the third slide groove through the first elastic element, the fixing rod extends through the inner wall of the third slide groove to the inside of the first slide groove, the size of the fixing rod is adapted to the size of the fixing hole, and the fixing rod and the fixing hole are engaged.

[0019] By adopting the above technical solution, the fixing rod and fixing hole are designed to facilitate the loading and unloading of the compensation plate.

[0020] As an optional solution to the technical solution of this application, the guiding component includes two fourth sliding grooves opened inside the wear-resistant layer, a cone head is slidably connected inside the fourth sliding groove, a connecting hole is opened on the cone head, a partition is fixedly connected to the bottom of the cone head, and a second elastic element is provided inside the fourth sliding groove.

[0021] As an optional solution of the technical solution in this application, the cone head is elastically connected to the gradient composite transition layer through the second elastic element. The end of the cone head away from the second elastic element extends through the inner wall of the fourth slide groove to the interior of the first slide groove. The size of the top of the cone head is adapted to the size of the conical groove. The partition is located inside the second elastic element. The partition extends through the surface of the gradient composite transition layer to the interior of the honeycomb unit elastic element.

[0022] By adopting the above technical solution, the cone head can guide the filling fluid into the honeycomb unit elastic element, and convert the pressure on the honeycomb unit elastic element into the power for the filling fluid to push the wear-resistant layer to compensate.

[0023] Beneficial effects: One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0024] 1. A whisker composite ceramic wear-resistant layer is set on the inner wall of the nozzle. Its hardness is much higher than that of conventional metals, copper-tungsten alloys and other alloy materials. After plasma spraying and laser remelting, its density is significantly improved, reducing the probability of powder particles embedding into the surface layer. At the same time, the ceramic has excellent chemical stability and does not react with plasma gas and high-temperature oxides, avoiding oxidation and corrosion of the inner wall of the nozzle. This significantly improves the wear resistance of the inner wall of the nozzle, extends the service life of the nozzle, and keeps the inner wall of the nozzle smooth and structurally stable, ensuring powder feeding and spraying accuracy.

[0025] 2. A honeycomb-shaped nickel-based superalloy elastic buffer layer is set in the middle layer. At high temperatures, the honeycomb unit can independently expand to absorb the thermal expansion difference between the inner ceramic layer and the outer gradient layer. The honeycomb unit independently bears the deformation. Even if a fatigue crack occurs in a single unit, it will not spread to other units. It efficiently absorbs the thermal expansion difference, avoids cracking and peeling caused by interlayer stress concentration, and ensures stable buffering performance at high temperatures. It is suitable for extreme spraying conditions and indirectly extends the service life of the spray head.

[0026] 3. Simultaneously, a gradient composite transition layer is set between the elastic buffer layer and the wear-resistant layer, and a tungsten-copper gradient layer is set between the elastic buffer layer and the nozzle to achieve a thermal expansion step transition of "ceramic → transition layer → nickel-based → gradient layer". This avoids large differences in expansion distance at the contact surface between the layers due to excessive thermal expansion differences, which could lead to interlayer delamination. It also eliminates stress abrupt changes between the buffer layer and the substrate, significantly improves the interlayer bonding strength, avoids multi-layer structure delamination failure, and thus ensures the long-term stability of the multi-layer structure, further extending the overall service life of the nozzle.

[0027] 4. A wear-resistant head is installed in the powder feeding channel to directly avoid the wear caused by the powder on the inner wall of the powder feeding channel during powder feeding, extend the service life of the channel, and prevent the powder from being accelerated and deflected under the action of the flame after being transported to the end of the powder feeding channel near the spray outlet, which would cause wear to the powder outlet and lead to the expansion of the powder outlet.

[0028] 5. During the preheating process of the spray gun, some of the filler liquid inside the compensation plate will be pushed into the groove by the pressure of the elastic buffer layer, filling the groove and covering the powder outlet. This prevents the wear head from being worn down before the first groove is reached, thus avoiding the powder contacting the powder outlet and causing wear. This achieves early isolation between the powder and the powder outlet, avoiding wear on the powder outlet before compensation is triggered, extending the overall service life of the wear head, avoiding premature scrapping due to localized damage, ensuring stable powder feeding trajectory and uniform powder output, indirectly improving coating quality consistency, and adapting to the preheating process without affecting the normal spraying rhythm.

[0029] 6. When the wear-resistant head is exposed in the first groove due to powder erosion, the filling liquid in the compensation plate will push the flexible compensation bushing out in time under the pressure of the elastic buffer layer, accurately filling the wear gap of the wear-resistant head. Through its own wear resistance, it quickly rebuilds the protective barrier, avoids direct contact between powder and the inner wall of the channel, thoroughly protects the inner wall of the powder feeding channel from damage, and does not require emergency shutdown, ensuring the continuous completion of the current spraying task, extending the protection cycle, reducing maintenance frequency and cost, and forming a full-stage protection in conjunction with the above-mentioned preheating protection.

[0030] 7. During the process of rebuilding the protective barrier with the flexible compensation bushing, time will be simultaneously allocated for the ceramic-based filling liquid to cure. The cured filling material will form a "rigid protective layer" together with the bushing. Even if the bushing is subsequently worn, the cured material can continue to resist powder erosion, ensuring that the channel body will not be damaged, extending the overall protection cycle, maintaining the geometric accuracy of the powder feeding channel, and ensuring the stability of the powder conveying trajectory and the coating quality. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a three-dimensional structural diagram of a plasma thermal spraying device used for tungsten-copper alloy welding heads.

[0033] Figure 2 This is a schematic diagram of the cross-sectional structure of the nozzle in a plasma thermal spraying device used for tungsten-copper alloy welding heads.

[0034] Figure 3 Plasma thermal spraying device for tungsten-copper alloy welding joints Figure 2 Enlarged structural diagram at point A in the middle.

[0035] Figure 4 Plasma thermal spraying device for tungsten-copper alloy welding joints Figure 2 Enlarged structural diagram at point B.

[0036] Figure 5 Plasma thermal spraying device for tungsten-copper alloy welding joints Figure 2 Enlarged structural diagram at point C.

[0037] Figure 6 Plasma thermal spraying device for tungsten-copper alloy welding joints Figure 2 Enlarged structural diagram at point D.

[0038] Figure 7 This is a schematic diagram showing the structural relationship between the powder feeding channel and the powder outlet in a plasma thermal spraying device used for tungsten-copper alloy welding heads.

[0039] Figure 8 This is a schematic diagram of the three-dimensional structure of the nozzle in a plasma thermal spraying device used for tungsten-copper alloy welding heads.

[0040] Figure 9 This is a schematic diagram showing the structural relationship and fit between the compensation plate and the wear-resistant layer in a plasma thermal spraying device used for tungsten-copper alloy welding heads.

[0041] Figure 10 This is a cross-sectional schematic diagram of the guiding component in a plasma thermal spraying device used for tungsten-copper alloy welding heads.

[0042] Figure 11 This is a schematic diagram showing the structural relationship and fit between the flexible compensation bushing and the compensation plate in a plasma thermal spraying device used for tungsten-copper alloy welding heads.

[0043] Figure 12 This is a three-dimensional structural diagram of the honeycomb-shaped unit elastic element in a plasma thermal spraying device used for tungsten-copper alloy welding heads.

[0044] Explanation of the labels in the diagram: 10. Main body of the spraying device; 101. Robotic arm; 102. Spray head; 103. Rear electrode; 104. Front electrode; 105. Medium channel; 106. Cooling inlet; 107. Cooling tank; 108. Cooling outlet; 109. Rotary clamp; 11. Wear-resistant layer; 12. Gradient composite transition layer; 13. Elastic buffer layer; 14. Tungsten-copper gradient layer; 15. Powder feeding channel; 16. Wear-resistant component; 161. Fixing base; 162. Wear-resistant head; 163. Groove; 164. Powder outlet; 17. Spraying outlet; 18. First chute; 19. Honeycomb Nested unit elastic element; 20, compensation component; 201, compensation plate; 202, sealing plug; 203, infusion channel; 204, outlet hole; 205, second slide groove; 206, slide plate; 207, diaphragm; 208, conical groove; 209, fixing hole; 21, flexible compensation bushing; 22, fixing component; 221, third slide groove; 222, slider; 223, fixing rod; 224, first elastic element; 225, lever; 23, guide component; 231, fourth slide groove; 232, cone head; 233, connecting hole; 234, partition; 235, second elastic element. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0046] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0047] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or a link; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0048] Reference Figures 1 to 12 This application provides a plasma thermal spraying device for tungsten-copper alloy welding heads, including wear-resistant components. The device includes a spraying device body 10, with a wear-resistant layer 11 inside the spraying device body 10 to resist powder erosion and high-temperature corrosion. A gradient composite transition layer 12 is provided between the wear-resistant layer 11 and the spraying device body 10. An elastic buffer layer 13 is provided between the gradient composite transition layer 12 and the spraying device body 10 to absorb expansion differences. A tungsten-copper gradient layer 14 is provided between the elastic buffer layer 13 and the spraying device body 10. A powder feeding channel 15 for conveying coating dust is provided inside the spraying device body 10. A wear-resistant component 16 for increasing the service life of the powder feeding channel 15 is provided inside the powder feeding channel 15. A spraying outlet 17 is provided inside the wear-resistant layer 11. A first chute 18 is provided inside the wear-resistant layer 11. A honeycomb-shaped unit elastic element 19 is provided inside the gradient composite transition layer 12.

[0049] The compensation component includes a compensation assembly 20 disposed in the first slide groove 18, a flexible compensation bushing 21 disposed on the compensation assembly 20 for compensating the wear portion of the wear-resistant assembly 16, a fixing assembly 22 disposed in the wear-resistant layer 11 for fixing the compensation assembly 20, and a guiding assembly 23 disposed inside the wear-resistant layer 11 for guiding the filling fluid.

[0050] Reference Figure 1 , Figure 2 and Figure 12This application provides a plasma thermal spraying device for tungsten-copper alloy welding heads. The main body 10 of the spraying device includes a robotic arm 101, on which a nozzle 102 is detachably connected. The nozzle 102 has a rear electrode 103 and a front electrode 104 internally, a medium channel 105, a cooling inlet 106 on the side of the robotic arm 101, a cooling tank 107 inside the nozzle 102, and a cooling outlet 108 at the top of the nozzle 102. The rotating fixture 109 has a cooling inlet 106 that is connected to the cooling outlet 108 via a cooling groove 107. The wear-resistant layer 11 is made of low thermal conductivity whisker composite ceramic material. The elastic buffer layer 13 has several honeycomb-shaped unit elastic elements 19 evenly distributed inside. The honeycomb-shaped unit elastic elements 19 are made of nickel-based superalloy material. The inner wall of the powder feeding channel 15 is made of the same material as the wear-resistant layer 11. The wear-resistant layer 11 is located on the side of the front electrode 104 away from the rear electrode 103. The spray outlet 17 is located on the side of the wear-resistant layer 11 away from the front electrode 104.

[0051] The robotic arm 101 is equipped with a cooling circulator, an air conveying device, and a powder feeder. The gradient composite transition layer 12 is divided into 5 to 7 levels according to the ceramic content of 100% → 80% → 50% → 20% → 0%, which realizes a "continuous and smooth transition" of thermal expansion from the wear-resistant layer to the buffer layer, eliminates stress abrupt changes, and takes into account both wear resistance and toughness. The tungsten content in the tungsten-copper gradient layer 14 gradually changes from 30% in the inner layer to 70% in the outer layer, which realizes a smooth transition of the thermal expansion coefficient between the middle layer and the nozzle 102, and avoids interface stress.

[0052] Reference Figures 2 to 5 This application provides a plasma thermal spraying device for tungsten-copper alloy welding heads. The wear-resistant component 16 includes a fixing seat 161 disposed on the side of the nozzle 102. A wear-resistant head 162 is fixedly connected to the fixing seat 161. A groove 163 is formed on the side of the wear-resistant head 162 near the first slide groove 18. The wear-resistant head 162 is made of a low thermal conductivity insulating material. Because whiskers are added to the ceramic material of the wear-resistant layer 11, its heat insulation effect is lower than that of the wear-resistant head 162. The side of the fixing seat 161 near the nozzle 102 passes through the powder feeding channel 15, and the wear-resistant head 162 is located inside the powder feeding channel 15. The side of the fixed base 161 away from the wear-resistant head 162 is detachably connected to the side of the nozzle 102. The powder feeding channel 15 is provided with a powder outlet 164. The powder outlet 164 is the part of the powder feeding channel 15 with greater wear pressure (when the powder is transported to the powder feeding channel 15, it will accelerate towards the spray outlet 17 under the negative pressure of the flame, and shift towards the powder outlet 164 along the direction of the flame, increasing the wear on the powder outlet 164). The powder outlet 164 is located on the side of the first groove 18 near the spray outlet 17. The size of the groove 163 is larger than the size of the powder outlet 164.

[0053] Reference Figures 2 to 11 This application provides a plasma thermal spraying device for tungsten-copper alloy welding heads. The compensation component 20 includes a compensation plate 201 slidably connected inside a first groove 18. The compensation plate 201 has a liquid infusion channel 203 inside and a sealing plug 202 inside. A plurality of liquid outlet holes 204 are evenly opened at the end of the compensation plate 201 away from the sealing plug 202. A second groove 205 is provided on the side of the compensation plate 201 near the spraying outlet 17. A slide plate 206 is slidably connected inside the second groove 205. A diaphragm 207 is fixedly connected on the side of the slide plate 206 near the liquid outlet holes 204. Two fixing holes 209 are opened on the compensation plate 201. Two conical grooves 208 are opened on the side of the compensation plate 201 near the gradient composite transition layer 12.

[0054] The compensating plate 201 is made of heat-insulating material. The conical groove 208 is connected to the infusion channel 203. Two fixing holes 209 are located on both sides of the infusion channel 203. The size of the compensating plate 201 is adapted to the size of the first slide 18. The first slide 18 extends through the inner wall of the wear-resistant layer 11 to the inside of the powder delivery channel 15. The flexible compensating bushing 21 is detachably connected to the slide plate 206 and the surface of the compensating plate 201. The side of the compensating plate 201 away from the outlet hole 204 abuts against the surface of the wear-resistant head 162. The flexible compensating bushing 21 is made of carbon fiber material.

[0055] Reference Figures 6 to 11 This application provides a plasma thermal spraying device for tungsten-copper alloy welding heads. The fixing component 22 includes a third slide groove 221 formed inside the wear-resistant layer 11. A slider 222 is slidably connected inside the third slide groove 221. A fixing rod 223 is fixedly connected to the top of the slider 222. A first elastic element 224 is provided on the side of the slider 222 away from the fixing rod 223. A lever 225 is fixedly connected to the slider 222. The lever 225 extends through the inner wall of the third slide groove 221 to the side of the wear-resistant layer 11 away from the front electrode 104. The slider 222 is elastically connected to the inner wall of the third slide groove 221 through the first elastic element 224. The fixing rod 223 extends through the inner wall of the third slide groove 221 to the inside of the first slide groove 18. The size of the fixing rod 223 is adapted to the size of the fixing hole 209. The fixing rod 223 and the fixing hole 209 are engaged.

[0056] Reference Figures 2 to 5This application provides a plasma thermal spraying device for tungsten-copper alloy welding heads. The guide component 23 includes two fourth grooves 231 formed inside the wear-resistant layer 11. A cone head 232 is slidably connected inside the fourth groove 231. A connecting hole 233 is formed on the cone head 232. A partition plate 234 is fixedly connected to the bottom of the cone head 232. A second elastic element 235 is provided inside the fourth groove 231. The cone head 232 is elastically connected to the gradient composite transition layer 12 through the second elastic element 235. The end of the cone head 232 away from the second elastic element 235 extends through the inner wall of the fourth groove 231 to the interior of the first groove 18. The size of the top of the cone head 232 is adapted to the size of the conical groove 208. The partition plate 234 is located inside the second elastic element 235 and extends through the surface of the gradient composite transition layer 12 to the interior of the honeycomb unit elastic element 19.

[0057] This application provides a plasma thermal spraying device for tungsten-copper alloy welding heads, the working principle and usage process of which are as follows:

[0058] First, the tungsten-copper alloy welding head to be coated is degreased, acid-washed to remove the oxide layer, and roughened by sandblasting. Then, the welding head is fixed on a rotating fixture 109 and rotated. Gradual preheating is performed according to the welding head's specifications. Simultaneously, working gas and coating powder are prepared. Then, the cooling circulation device within the robotic arm 101 is activated, allowing cooling water to enter the cooling tank 107 within the nozzle 102 through the cooling inlet 106 and exit through the cooling outlet 108 into the cooling device, achieving circulating cooling of the nozzle 102. Simultaneously, the sealing plug 202 is opened to inject ceramic-based filling liquid into the infusion channel 203, filling it completely and allowing it to enter the two honeycomb-shaped unit elastic elements 19 through the two connecting holes 233. The sealing plug 202 is then closed. Subsequently, pure Ar protective gas is introduced into the medium channel 105 through the gas supply device within the robotic arm 101, allowing it to enter the nozzle 102 and exit the gun. The air inside the nozzle is heated, and then the arc between the rear electrode 103 and the front electrode 104 is triggered by the high-frequency arc igniter. The arc pressure and arc flow are adjusted to the preset values ​​to form a stable plasma flame. The flame is kept stable for 1-2 minutes to make the temperature of the anode nozzle of the spray gun uniform. After that, the robotic arm 101 is controlled by the CNC system to drive the nozzle 102 to move along the reciprocating trajectory to spray the tungsten copper alloy welding head. The distance between the nozzle 102 and the surface of the welding head is kept at 100-150mm. Then the powder feeder in the nozzle 102 is activated to transport the powder through the fixed seat 161 and the inside of the wear-resistant head 162 to the "core heating zone" of the flame. After the powder enters the high-temperature flame, it absorbs heat rapidly within a few tenths of a second and goes through the process of "preheating → softening → melting". At the same time, the high-speed plasma flow drives the molten droplets to accelerate and form a "molten droplet jet flow", which is sprayed from the spray outlet 17 onto the tungsten copper alloy welding head. The molten powder droplets hit the surface of the tungsten copper welding head at high speed and form a coating through "rapid solidification-layered accumulation".

[0059] The wear-resistant layer 11 is made of low thermal conductivity whisker composite ceramic material, which has a hardness much higher than that of conventional metals. After plasma spraying and laser remelting densification treatment, the density of the ceramic can be improved, reducing the probability of powder particles embedding into the surface layer. At the same time, the ceramic has excellent chemical stability and does not react with plasma gas and high-temperature oxides, completely avoiding oxidation and corrosion of the inner wall of the nozzle. The honeycomb nickel-based superalloy elastic buffer layer can absorb the expansion difference between the inner ceramic layer and the outer gradient layer by independently expanding the unit at high temperature. The honeycomb unit independently bears the deformation, and even if a fatigue crack occurs in a single unit, it will not spread to other units. A gradient composite transition layer 12 is set between the elastic buffer layer 13 and the wear-resistant layer 11, and a tungsten copper gradient layer 14 is set between the elastic buffer layer 13 and the nozzle 102 to realize the thermal expansion step transition of "ceramic → transition layer → nickel-based → gradient layer", avoiding interlayer delamination caused by excessive thermal expansion difference and eliminating stress abrupt change between the buffer layer and the substrate.

[0060] When the wear-resistant layer 11 expands due to heat, it compresses the honeycomb-shaped elastic element 19, causing it to deform. Simultaneously, it increases the hydraulic pressure within the two honeycomb-shaped elastic elements 19 storing the filling fluid, increasing the pressure applied to the flexible compensation bushing 21. This causes a portion of the flexible compensation bushing 21 to enter the groove 163, filling it completely and covering the powder outlet 164. This also causes the slide plate 206 to slide within the second slide groove 205. Since the wear-resistant head 162 is a low-thermal-conductivity insulating material, the contact area between the flexible compensation bushing 21 and the wear-resistant head 162 does not cure prematurely. While the insulation effect of the wear-resistant layer 11 is lower than that of the wear-resistant head 162, it still provides some insulation. Therefore, the filling fluid inside the area where the flexible compensation bushing 21 and the wear-resistant layer 11 are in contact cures slowly. Even if it cures, it will not affect the subsequent entry of the filling fluid into the flexible compensation bushing 21 through the outlet hole 204. When the wear-resistant head 162 is worn down by the powder to the point where it is about to exit... When the powder outlet 164 is exposed, the flexible compensation bushing 21 will be further moved out of the gap under the action of hydraulic pressure to fill the worn part of the wear-resistant head 162. This prevents the wear-resistant head 162 from continuing to convey powder and causing wear to the inner wall of the powder feeding channel 15 and the powder outlet 164. It will also drive the slide plate 206 to slide in the second slide groove 205 again. At this time, the alarm in the compensation plate 201 will be triggered to remind the staff to replace the wear-resistant head 162 after this coating is completed, observe the wear of the flexible compensation bushing 21, and clean the solidified filling material inside the flexible compensation bushing 21. The wear resistance of the flexible compensation bushing 21 itself can buy time for the filling liquid to solidify. The filling liquid only takes a few minutes to solidify, while it takes a long time for the flexible compensation bushing 21 to be worn through, which is enough for the filling liquid inside to solidify. Even if the flexible compensation bushing 21 is worn and the solidified filling material is exposed, it will still protect the inner wall of the powder feeding channel 15.

[0061] After spraying, remove the nozzle 102 from the robotic arm 101, then pull the fixing seat 161 away from the nozzle 102 to remove the worn wear-resistant head 162. Then, push the lever 225 downward to make the slider 222 move down, compress the first elastic element 224 and cause the fixing rod 223 to disengage from the fixing hole 209. Then, pull the compensation plate 201 away from the nozzle 102, so that the conical groove 208 presses the side of the cone head 232, and the cone head 232 moves down into the fourth sliding groove 231. The compensation plate 201 can then be removed for observation or replacement of the flexible compensation bushing 21.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A plasma thermal spraying device for tungsten-copper alloy welding heads, characterized in that: include The wear-resistant component includes a spraying device body (10), the inside of which is provided a wear-resistant layer (11) for resisting powder erosion and high-temperature corrosion, a gradient composite transition layer (12) between the wear-resistant layer (11) and the spraying device body (10), an elastic buffer layer (13) for absorbing expansion difference between the gradient composite transition layer (12) and the spraying device body (10), a tungsten-copper gradient layer (14) between the elastic buffer layer (13) and the spraying device body (10), a powder feeding channel (15) for conveying coating dust inside the spraying device body (10), a wear-resistant component (16) for increasing the service life of the powder feeding channel (15) inside the powder feeding channel (15), a spraying outlet (17) inside the wear-resistant layer (11), a first chute (18) inside the wear-resistant layer (11), and a honeycomb unit elastic element (19) inside the gradient composite transition layer (12). The compensation component includes a compensation assembly (20) disposed in the first groove (18), the compensation assembly (20) being provided with a flexible compensation bushing (21) for compensating the wear portion of the wear-resistant assembly (16), the wear-resistant layer (11) being provided with a fixing assembly (22) for fixing the compensation assembly (20), and the wear-resistant layer (11) being provided with a guiding assembly (23) for guiding the filling fluid. The compensation component (20) includes a compensation plate (201) slidably connected inside the first groove (18). The compensation plate (201) has an infusion channel (203) inside and a sealing plug (202) inside. A plurality of liquid outlet holes (204) are evenly opened at one end of the compensation plate (201) away from the sealing plug (202). A second groove (205) is provided on the side of the compensation plate (201) near the spray outlet (17). A slide plate (206) is slidably connected inside the second groove (205). A diaphragm (207) is fixedly connected on the side of the slide plate (206) near the liquid outlet hole (204). Two fixing holes (209) are opened on the compensation plate (201). Two conical grooves (208) are opened on the side of the compensation plate (201) near the gradient composite transition layer (12). The fixing component (22) includes a third slide groove (221) formed inside the wear-resistant layer (11), a slider (222) is slidably connected inside the third slide groove (221), a fixing rod (223) is fixedly connected to the top of the slider (222), a first elastic element (224) is provided on the side of the slider (222) away from the fixing rod (223), and a lever (225) is fixedly connected to the slider (222). The guide component (23) includes two fourth grooves (231) opened inside the wear-resistant layer (11). A cone (232) is slidably connected inside the fourth groove (231). A connecting hole (233) is opened on the cone (232). A partition (234) is fixedly connected to the bottom of the cone (232). A second elastic element (235) is provided inside the fourth groove (231).

2. The plasma thermal spraying device for tungsten-copper alloy welding heads according to claim 1, characterized in that: The main body (10) of the spraying device includes a robotic arm (101), on which a nozzle (102) is attached and detached. The nozzle (102) has a rear electrode (103) and a front electrode (104) inside. The nozzle (102) has a medium channel (105). The side of the robotic arm (101) has a cooling inlet (106). The inside of the nozzle (102) has a cooling groove (107). The top of the nozzle (102) has a cooling outlet (108). The side of the robotic arm (101) has a rotating clamp (109).

3. The plasma thermal spraying device for tungsten-copper alloy welding heads according to claim 2, characterized in that: The cooling inlet (106) is connected to the cooling outlet (108) through the cooling tank (107). The wear-resistant layer (11) is made of low thermal conductivity whisker composite ceramic material. The elastic buffer layer (13) has a number of honeycomb-shaped unit elastic elements (19) evenly distributed inside. The honeycomb-shaped unit elastic elements (19) are made of nickel-based superalloy material. The inner wall material of the powder feeding channel (15) is the same as that of the wear-resistant layer (11). The wear-resistant layer (11) is located on the side of the front electrode (104) away from the rear electrode (103). The spraying outlet (17) is located on the side of the wear-resistant layer (11) away from the front electrode (104).

4. The plasma thermal spraying apparatus for tungsten-copper alloy welding heads according to claim 2, characterized in that: The wear-resistant component (16) includes a fixed seat (161) disposed on the side of the nozzle (102), and a wear-resistant head (162) is fixedly connected to the fixed seat (161). The wear-resistant head (162) has a groove (163) on the side near the first slide groove (18). The wear-resistant head (162) is made of a low thermal conductivity insulation material. The side of the fixed seat (161) near the nozzle (102) passes through the powder feeding channel (15). The wear-resistant head (162) is located inside the powder feeding channel (15). The side of the fixed seat (161) away from the wear-resistant head (162) is detachably connected to the side of the nozzle (102).

5. The plasma thermal spraying apparatus for tungsten-copper alloy welding joints according to claim 4, characterized in that: The compensating plate (201) is made of heat-insulating material. The conical groove (208) is connected to the infusion channel (203). The two fixing holes (209) are located on both sides of the infusion channel (203). The size of the compensating plate (201) is adapted to the size of the first chute (18). The first chute (18) extends through the inner wall of the wear-resistant layer (11) to the inside of the powder feeding channel (15). The flexible compensating bushing (21) is detachably connected to the slide plate (206) and the surface of the compensating plate (201). The side of the compensating plate (201) away from the outlet hole (204) abuts against the surface of the wear-resistant head (162). The flexible compensating bushing (21) is made of carbon fiber material.

6. The plasma thermal spraying apparatus for tungsten-copper alloy welding joints according to claim 5, characterized in that: The dial (225) extends through the inner wall of the third slide groove (221) to the side of the wear-resistant layer (11) away from the front electrode (104). The slider (222) is elastically connected to the inner wall of the third slide groove (221) through the first elastic element (224). The fixing rod (223) extends through the inner wall of the third slide groove (221) to the interior of the first slide groove (18). The size of the fixing rod (223) is adapted to the size of the fixing hole (209). The fixing rod (223) is engaged with the fixing hole (209).

7. The plasma thermal spraying apparatus for tungsten-copper alloy welding joints according to claim 6, characterized in that: The cone (232) is elastically connected to the gradient composite transition layer (12) through the second elastic element (235). The end of the cone (232) away from the second elastic element (235) extends through the inner wall of the fourth groove (231) to the interior of the first groove (18). The size of the top of the cone (232) is adapted to the size of the conical groove (208). The partition (234) is located inside the second elastic element (235). The partition (234) extends through the surface of the gradient composite transition layer (12) to the interior of the honeycomb unit elastic element (19).

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