An ultrasonic vibration-assisted global transient cladding device and method

Abstract

This invention discloses an ultrasonic vibration-assisted full-domain transient cladding device and method in the field of surface strengthening technology for components. The cladding chamber is equipped with an inert gas cylinder, an ultrasonic generator, and a vacuum pump on its exterior. Inside the cladding chamber, from top to bottom, are arranged an ultrasonic vibrating head, a perforated graphite felt, coating powder, a workpiece, and a third telescopic motor. The top surface of the workpiece is covered with a layer of coating powder. The perforated graphite felt has through-holes, and an ultrasonic vibrating head extends into one of the holes in the perforated graphite felt. Using air as a carrier, ultrasonic vibration is transmitted to the cladding layer. The workpiece itself does not vibrate, allowing the metal dendrites in the cladding layer to fracture during metal crystallization, promoting the growth of new crystal nuclei and achieving grain refinement. After the cladding layer is formed, the DC power supply is turned off, but the ultrasonic vibrating head continues to operate. The cladding layer of the workpiece impacts the ultrasonic vibrating head, forging the cladding layer and further improving its plasticity and mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of surface strengthening technology for components, and specifically to a heating and cladding device and method for the surface of components. Background Technology

[0002] Wear and corrosion are both material loss processes that occur on the surface of parts, and most part failures start from the surface. Therefore, adopting surface strengthening measures to delay and control the damage to the surface of parts, and improve the wear resistance and corrosion resistance of the surface of parts can extend the service life of parts, thereby reducing costs and improving efficiency.

[0003] Currently, the main traditional cladding method for surface strengthening of parts is laser cladding. The advantages and disadvantages of laser cladding are as follows: Laser cladding involves rapid heating and cooling, resulting in a uniform and dense cladding layer with few micro-defects. However, the cladding equipment is relatively expensive, and the surface roughness of the parts after processing is high. To improve existing laser cladding processes, a full-domain transient cladding process has emerged. Full-domain transient cladding is a novel surface strengthening technology. It involves pre-coating a material onto the substrate surface, then using a transient high-current flowing through a heating device such as graphite felt to generate instantaneous extremely high thermal radiation, melting the pre-coated material and bonding it to the substrate. The cladding layer prepared by this process forms a metallurgical bond with the substrate, exhibiting high bonding strength and properties such as wear resistance and corrosion resistance, thus improving the reliability of the parts. This process has significant advantages such as simple equipment, low cost, and high efficiency.

[0004] Chinese Patent Publication No. CN202011350321.6 discloses an ultrasonic vibration-assisted laser cladding device and method for tungsten-tantalum-niobium alloys. This invention applies ultrasonic vibration uniformly during the laser cladding process, resulting in a well-formed cladding layer and effective elimination and suppression of porosity. However, this method fixes the substrate to an ultrasonic vibration table, causing the substrate to vibrate along with the table, which may lead to defects such as microcracks and microvoids within the metal material. Chinese Patent Publication No. CN213835541U discloses an electromagnetic composite ultrasonic vibration-assisted laser cladding crack suppression device. This device uses an ultrasonic transducer and excitation coil to control the microstructure of the molten pool on the cladding substrate. However, laser cladding often results in component segregation and resulting microstructure inhomogeneity. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in existing surface strengthening treatments for components by proposing an ultrasonic vibration-assisted full-domain transient cladding device, which employs ultrasonic vibration assistance for ultrafast high-temperature sintering.

[0006] The technical solution of the ultrasonic vibration-assisted full-domain transient cladding device of the present invention is as follows: It includes a cladding box, characterized in that: an inert gas cylinder, an ultrasonic generator, and a vacuum pump are provided outside the cladding box; the interior of the cladding box, from top to bottom, is provided with an ultrasonic vibrating head, a perforated graphite felt, coating powder, a workpiece to be processed, and a third telescopic motor; the top surface of the workpiece to be processed is covered with a layer of coating powder; multiple ultrasonic vibrating heads are arranged vertically, and the perforated graphite felt is arranged horizontally with through holes; the number of ultrasonic vibrating heads is the same as the number of holes on the perforated graphite felt, and one ultrasonic vibrating head extends into one hole of the perforated graphite felt; multiple ultrasonic vibrating heads are connected to the ultrasonic generator outside the cladding box via control lines; each side of the perforated graphite felt has a graphite felt clamp made of conductive metal material, and the graphite felt clamp is connected to a DC power supply outside the cladding box; the workpiece to be processed... On each of the two transverse sides of the workpiece is a boron nitride baffle, which is slidably connected to the two sides of the workpiece. The bottom of the boron nitride baffle is slidably connected to the bottom surface of the cladding box, and the top of the boron nitride baffle is fixedly supporting the graphite felt fixture. A horizontally arranged second telescopic motor is set between the transverse side of each boron nitride baffle and the inner wall of the cladding box. The output end of the second telescopic motor is coaxially fixedly connected to a second telescopic rod, and one second telescopic rod is fixedly connected to one boron nitride baffle. A vertically upward arranged third telescopic motor is set between the bottom of the workpiece and the bottom of the cladding box. The output end of the third telescopic motor can drive the workpiece via the third telescopic rod. Along the longitudinal direction of the cladding box, a horizontally arranged first telescopic motor is set on each of the front and rear sides of the workpiece. The output end of the first telescopic motor can drive the workpiece to move via the first telescopic rod. A powder spreader is set in front of the ultrasonic vibrating head in the longitudinal direction.

[0007] Furthermore, the control center is fixedly connected to the side wall of the cladding box. The control center controls the DC power supply, inert gas cylinder, ultrasonic generator, vacuum pump, powder spreader, first telescopic motor, second telescopic motor and third telescopic rod via control lines.

[0008] Furthermore, the cladding chamber is equipped with distance sensors that detect the lateral, longitudinal, and vertical positions of the workpiece to be processed, as well as a vacuum sensor for detecting the vacuum level inside the cladding chamber. All sensors are connected to the control center via signal lines.

[0009] The technical solution of the processing method of the ultrasonic vibration-assisted full-domain transient cladding device of the present invention includes the following steps:

[0010] Step 1: The coating powder is placed in the powder spreader. The workpiece is initially positioned below the powder spreader. The vacuum pump first evacuates the gas in the cladding chamber, and then the inert gas cylinder is opened to inject inert gas into the cladding chamber.

[0011] Step 2: The first telescopic motor pushes the workpiece to be processed to move to the rear side, while the powder spreader spreads the coating powder on the upper surface of the workpiece. When the coating powder is spread, the workpiece is pushed by the first telescopic rod to the bottom of the perforated graphite felt. The first telescopic motor returns to the initial position and controls the powder spreader to stop working.

[0012] Step 3: The two second telescopic motors stop working when they simultaneously push the boron nitride baffles on both sides to contact the workpiece.

[0013] Step 4: The third telescopic motor drives the workpiece to be processed to rise upwards, and the coating powder is close to the perforated graphite felt but does not make contact. The third telescopic motor stops and remains in this position.

[0014] Step 5: The ultrasonic generator starts working. After the ultrasonic vibrating head stabilizes, the DC power supply is turned on. The transient heat generated by the perforated graphite felt causes the coating powder to bond with the workpiece to form a cladding layer.

[0015] Step 6: After the cladding layer is formed, turn off the DC power supply. The ultrasonic vibrating head continues to work until the cladding layer cools down and the ultrasonic vibrating head stops working.

[0016] Step 7: The third telescopic motor continues to move upward, driving the cladding layer of the workpiece to impact the ultrasonic vibrating head and forging the cladding layer;

[0017] Step 8: After forging is completed, the cladding layer is cooled to room temperature. The third telescopic motor descends, and the workpiece is lowered to its original position. The first telescopic motor on the longitudinal rear side drives the workpiece to its initial position.

[0018] Furthermore, the workpiece is ultrasonically cleaned with alcohol and then dried before being sandblasted.

[0019] Furthermore, the coating powder is pre-dried in a vacuum drying oven at 100°C for 3–5 hours. The coating powder can be any type of cemented carbide powder.

[0020] Furthermore, in step one, when the gas pressure inside the cladding chamber is lower than 100 Pa, the vacuum pump is turned off; when the gas pressure inside the cladding chamber reaches the standard atmospheric pressure, the inert gas cylinder is turned off; then the vacuum pump is started again to evacuate the chamber, and this process of evacuating the chamber and filling it with inert gas is repeated 3 to 5 times.

[0021] Furthermore, in step four, the gap between the porous graphite felt and the coating powder is 20–30 mm.

[0022] Furthermore, in step five: the output power of the ultrasonic generator is 700W, generating vibrations of 35kHz and 4µm. After waiting for 3 minutes, the ultrasonic vibration head stabilizes.

[0023] Furthermore, when the temperature of the cladding layer is below 1000℃, the output power of the ultrasonic vibrator is 700W, and the maximum current density through the porous graphite felt is 3.5*10. 5 A / m 2 When the temperature rises above 1000℃, the maximum output power of the ultrasonic vibrator is 1000W, and the maximum current density through the porous graphite felt is 7.5*10. 5 A / m 2 The temperature of the perforated graphite felt reaches about 3000℃, and the holding time is 20-30 seconds for cladding the workpiece.

[0024] The advantages that emerge after adopting the above technical solution are as follows:

[0025] 1. This invention utilizes air as a carrier to transmit ultrasonic vibration to the cladding layer, while the workpiece itself does not vibrate. This allows the metal dendrites in the cladding layer to crack during the metal crystallization process, promoting the growth of new crystal nuclei and achieving grain refinement. This results in rapid overall forming and cladding strengthening of the part's surface, reducing the occurrence of cracks on the coating surface, significantly improving the surface morphology of the clad part, reducing the cost of coating processing, and featuring energy saving and high efficiency.

[0026] 2. Traditional laser cladding often produces defects such as component segregation, porosity, and cracks. This invention utilizes ultrasonic-assisted electrothermal cladding to effectively avoid these defects. Direct current is applied to both sides of the graphite felt. The Joule heat generated by the instantaneous high current in the graphite felt instantly raises its temperature to the required cladding temperature, up to 3000℃. Using the graphite felt as a heat source, heat is transferred to the coating material through thermal radiation and heat transfer, causing it to melt and form a metallurgical bond with the part. This reduces cladding time, increases cladding efficiency, and achieves rapid cladding.

[0027] 3. After the cladding is completed, the present invention uses an ultrasonic vibrating head to forge the cladding layer, which can further improve the plasticity and mechanical properties of the cladding layer.

[0028] 4. The cladding process of the present invention is uniformly controlled by the control center, which facilitates the adjustment of cladding parameters and the control of start and stop. The operation is simple and can effectively reduce the workload of the staff. Attached Figure Description

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0030] Figure 1 This is an overall schematic diagram of an ultrasonic vibration-assisted full-domain transient cladding device according to the present invention;

[0031] Figure 2 for Figure 1Enlarged transverse cross-sectional view of the internal structure of the cladding box;

[0032] Figure 3 for Figure 1 Enlarged longitudinal sectional view of the internal structure of the cladding box;

[0033] Figure 4 for Figure 3 Diagram showing the powder spreading process on parts awaiting processing;

[0034] Figure 5 for Figure 3 The image shows the state of the workpiece being pushed to the powder-spreading position after it has been clad.

[0035] The annotations in the attached figures are explained as follows:

[0036] 1-DC power supply; 2-Clad box; 3-Control center; 4-Inert gas cylinder; 5-Ultrasonic generator; 6-Vacuum pump; 8-Ultrasonic vibrator; 9-Graphite felt clamp; 10-Second distance sensor; 11-Second telescopic motor; 12-Second telescopic rod; 13-Boron nitride baffle; 14-Third distance sensor; 15-Third telescopic motor; 16-Third telescopic rod; 17-Workpiece to be processed; 18-Coating powder; 19-Perforated graphite felt; 20-Powder spreader; 21-Scraper; 22-First distance sensor; 23-First telescopic motor; 24-First telescopic rod; 25-Vacuum sensor; 26-Temperature sensor. Detailed Implementation

[0037] See Figure 1 This invention discloses an ultrasonic vibration-assisted full-range transient cladding device, comprising a DC power supply 1, a cladding chamber 2, a control center 3, an inert gas cylinder 4, an ultrasonic generator 5, and a vacuum pump 6. The DC power supply 1, control center 3, inert gas cylinder 4, ultrasonic generator 5, and vacuum pump 6 are all located outside the cladding chamber 2, and the control center 3 is fixed to the side wall of the cladding chamber 2.

[0038] The inert gas cylinder 4 is connected to the cladding chamber 2 via a gas hose, and the vacuum pump 6 is also connected to the cladding chamber 2 via a gas hose. The connection between the cladding chamber 2 and the gas hose uses a flange and a rubber sealing ring to ensure the sealing performance of the cladding chamber 2. The control center 3 is connected to the vacuum pump 6, the DC power supply 1, and the ultrasonic generator 5, controlling their respective operations. A pressure reducing valve is installed on the inert gas cylinder 4, and the pressure reducing valve is connected to the control center 3. The control center 3 can control the opening and closing of the pressure reducing valve, thereby allowing the inert gas cylinder 4 to supply inert gas into the cladding chamber 2 or stop supplying it.

[0039] See Figure 2 and Figure 3Inside the cladding box 2, from top to bottom, are arranged an ultrasonic vibrating head 8, a perforated graphite felt 19, coating powder 18, a workpiece 17 to be processed, and a third telescopic motor 15. The ultrasonic vibrating heads 8 are arranged vertically, with multiple heads connected to the top surface of the cladding box 2. The perforated graphite felt 19 is arranged horizontally, with multiple arrayed, vertically penetrating holes. The number of ultrasonic vibrating heads 8 is the same as the number of holes on the perforated graphite felt 19, and each head corresponds to one hole, with one ultrasonic vibrating head 8 extending into one hole of the perforated graphite felt 19.

[0040] Inside the cladding box 2, on each side of the perforated graphite felt 19, there is a graphite felt clamp 9, which holds the perforated graphite felt 19 in place. The graphite felt clamp 9 is made of conductive metal and is electrically connected to an external DC power supply 1. The positive and negative terminals of the external DC power supply 1 are connected to the graphite felt clamp 9 by bolts, forming an electrical circuit between the DC power supply 1 and the perforated graphite felt 19.

[0041] On each side of the workpiece 17 to be processed is a boron nitride baffle 13, which is slidably connected to the sides of the workpiece 17 to be processed, serving to position the workpiece 17 laterally. A track groove mechanism is provided between the side wall of the boron nitride baffle 13 and the side wall of the workpiece 17 to be processed, allowing the workpiece 17 to move up and down between the two boron nitride baffles 13.

[0042] The bottom of the boron nitride baffle 13 is slidably connected to the bottom surface of the cladding box 2, allowing it to move laterally left and right along the bottom surface of the cladding box 2. A track groove mechanism is provided between the bottom of the boron nitride baffle 13 and the bottom surface of the cladding box 2, enabling the boron nitride baffle 13 to move along the cladding box 2. The top of the boron nitride baffle 13 is fixedly supported by the graphite felt clamp 9 directly above it. The boron nitride baffle 13 is made of boron nitride, which, due to its high stability and high resistivity, can be used to isolate current and prevent the current on the graphite felt clamp 9 from passing through the metal shell of the cladding box 2, thus affecting the heating efficiency.

[0043] On the lateral side of each boron nitride baffle 13, a second telescopic motor 11 is installed between each boron nitride baffle 13 and the inner wall of the cladding box 2. The second telescopic motor 11 is horizontally arranged, its housing is fixed to the inner wall of the cladding box 2, and its output end is coaxially fixedly connected to a second telescopic rod 12. The second telescopic rod 12 extends horizontally towards the boron nitride baffle 13 and is fixedly connected to it. The second telescopic motor 11 is connected to the control center 3 through a control line to control the operation of the two second telescopic motors 11, thereby driving the corresponding two boron nitride baffles 13 to move laterally left and right, thereby laterally positioning or releasing the workpiece 17 to be processed.

[0044] Next to each of the second telescopic motors 11, a second distance sensor 10 is installed on the inner wall of the cladding box 2 to detect the lateral position of the boron nitride baffle 13. The second distance sensor 10 is connected to the control center 3 via a signal line to transmit the position signal of the boron nitride baffle 13 to the control center 3, and the control center 3 adjusts the second telescopic motors 11 according to the position signal.

[0045] A coating powder 18 is applied to the top surface of the workpiece 17. The porous graphite felt 19 generates transient thermal radiation under a high transient current, which melts the coating powder 18 and bonds it to the workpiece 17 to form a cladding layer. A DC power supply 1 is used to allow a high transient current to pass through the porous graphite felt 19. This high transient current generates a high transient temperature, which effectively ensures the grain refinement of the coating powder 18.

[0046] A temperature sensor 26 is installed inside the cladding chamber 2, close to the coating powder 18, to detect the temperature of the coating powder 18 in real time. The temperature sensor 26 is connected to the control center 3 via a signal line, transmitting the temperature signal to the control center 3. The control center 3 adjusts the output power of the DC power supply 1 according to the temperature signal to regulate the temperature of the coating powder 18.

[0047] The ultrasonic vibrating head 8 is connected to the ultrasonic generator 5 outside the cladding box 2 via a control line. The ultrasonic generator 5 has a power amplifier circuit. The power amplifier circuit rectifies and filters the AC voltage signal, amplifies the AC signal, converts the AC signal into an electrical oscillation signal of ultrasonic frequency, and drives the ultrasonic vibrating head 8 to work, obtain the required high-frequency oscillation energy, and emits this vibration energy to apply ultrasonic vibration to the coating powder 18 below it. During the metal crystallization process, the energy generated by the vibration can break the metal dendrites, promote the growth of new crystal nuclei, and achieve the purpose of grain refinement.

[0048] A third telescopic motor 15 is installed between the bottom of the workpiece 17 and the bottom of the cladding box 2. The third telescopic motor 15 is arranged vertically upward, and its output shaft is vertically upward and fixedly connected to a third telescopic rod 16. Supported by the third telescopic rod 16 at the bottom of the workpiece 17, the motor can move the workpiece 17 up and down to accommodate workpieces 17 of different heights. The third telescopic motor 15 is connected to the control center 3 via a control line.

[0049] A third distance sensor 14 is installed at the bottom of the cladding box 2 to detect the vertical position of the workpiece 17 to be processed. The third distance sensor 14 is connected to the control center 3 via a signal line to transmit the position signal to the control center 3. The control center 3 adjusts the third telescopic motor 15 according to the position signal.

[0050] See Figure 3 and Figure 4Along the longitudinal direction of the cladding box 2, a first telescopic motor 23 is provided on both the front and rear sides of the workpiece 17 to be processed. The first telescopic motor 23 is connected to the control center 3 via a control line. The first telescopic motor 23 is arranged horizontally and fixed on the inner side wall of the cladding box 2 in the longitudinal direction. The output end of the first telescopic motor 23 is coaxially fixedly connected to the first telescopic rod 24. The workpiece 17 to be processed can be moved back and forth by pushing the first telescopic rod 24 in the longitudinal front and rear direction.

[0051] Inside the cladding box 2, a first distance sensor 22 is set next to the first telescopic motor 23. The first distance sensor 22 is connected to the control center 3 via a signal line to detect the longitudinal position of the workpiece 17 and transmit the position signal to the control center 3. The control center 3 adjusts the first telescopic motor 23 according to the position signal.

[0052] A powder spreader 20 is positioned longitudinally in front of the ultrasonic vibrating head 8. The powder spreader 20 is fixed to the top surface of the cladding box 2 and connected to the control center 3 via a control line. A scraper 21 is connected to the bottom of the powder spreader 20. When the first telescopic rod 24 pushes the workpiece 17 to be processed directly below the powder spreader 20, the control center 3 outputs a signal to the powder spreader 20, and the powder spreader 20 begins to spread coating powder 18 onto the surface of the workpiece 17. The pushing speed of the first telescopic motor 23 is matched with the powder spreading speed of the powder spreader 20, so that the coating powder 18 is evenly spread on the surface of the workpiece 17. At the same time, the scraper 21 scrapes the powder on the surface of the workpiece 17 to ensure the uniformity of powder distribution. The thickness of the coating powder 18 is 2-3 mm.

[0053] See Figure 4 Before cladding, the first telescopic rod 24 on the longitudinal rear side drives the workpiece 17 to the bottom of the powder spreader 20 and then returns to its initial position. See also Figure 5 The first telescopic rod 24 on the longitudinal front side drives the workpiece 17 to complete the powder spreading. After the powder spreading is completed, the workpiece 17 is driven by the first telescopic rod 24 on the longitudinal front side to be directly below the perforated graphite felt 19, and then returns to the initial position.

[0054] A vacuum sensor 25 is installed on the inner wall of the cladding chamber 2 to detect the vacuum signal inside the cladding chamber 2 and transmit this signal to the control center 3. The control center 3 controls the start and stop of the vacuum pump 6 based on this signal.

[0055] The control center 3 uniformly controls various parameters of the cladding process. The control center 3 receives signals from the detection elements such as the first distance sensor 22, the second distance sensor 10, the third distance sensor 14, the vacuum sensor 25, and the temperature sensor 26, and outputs signals to the actuators such as the first telescopic motor 23, the second telescopic motor 11, the third telescopic motor 15, the ultrasonic vibrator 8, the vacuum pump 6, and the DC power supply 1, which can effectively ensure the accuracy of position, temperature, etc. in the cladding process.

[0056] When the ultrasonic vibration-assisted full-domain transient cladding device of this invention is in operation, the workpiece 17 to be clad needs to be ultrasonically cleaned with alcohol beforehand. After cleaning for a set time, it is taken out and dried for later use. The ultrasonic cleaning time can be determined according to the actual size of the workpiece 17, but it is necessary to ensure that the stains on the surface of the workpiece 17 are cleaned. Then, the workpiece 17 is sandblasted. A high-pressure sandblasting machine is used to pre-treat the surface of the workpiece 17. The air compressor pressure of the sandblasting machine is 0.3-0.5MPa. The purpose of sandblasting is twofold: first, to appropriately increase the surface roughness of the part and increase the contact area between the surface and the coating, thereby effectively ensuring the bonding strength of the coating; second, to further remove oxides and some impurities from the surface of the part, so as to avoid affecting the metallurgical bonding between the coating and the substrate. 46# brown corundum abrasive is selected for sandblasting. The sandblasting time is determined according to the size of the workpiece 17 to ensure that the sandblasting process is uniform and stable. After sandblasting, the residual abrasive particles on the surface of the workpiece 17 are blown away with high-pressure air and then it is ready for use.

[0057] When the full-area transient cladding device of this invention is in operation, the coating powder 18 needs to be pre-dried in a vacuum drying oven at 100°C for 3-5 hours to remove moisture from the alloy powder and prevent the formation of a large number of pores during the cladding process. The coating powder 18 can be any industrially commonly used cemented carbide powder. The treated coating powder 18 is then placed in the powder spreader 20.

[0058] To achieve the cladding of the cemented carbide powder in the coating powder 18, the temperature generated needs to reach the melting point of the coating powder 8.

[0059] For workpieces 17 of different sizes, the size of the perforated graphite felt 19 and the configuration of the DC power supply are different, and the required current and voltage parameters are also different, which determines the current density passing through the perforated graphite felt 19.

[0060] See Figure 1-5 The global transient cladding method adopts the following steps:

[0061] Step 1: Pre-treatment of workpiece 17. After sanding the upper surface of workpiece 17 with sandpaper, ultrasonically clean it with anhydrous ethanol for 10 minutes, and dry it at 100℃ for 30 minutes.

[0062] Step Two: Place the pre-treated workpiece 17 into the cladding chamber 2. Initially, the workpiece 17 is positioned below the powder spreader 20. To ensure complete sealing of the cladding chamber 2, the control center 3 outputs a signal to the vacuum pump 6, which starts to evacuate the gas inside the cladding chamber 2. The vacuum sensor 25 monitors the gas pressure inside the cladding chamber 2 in real time and outputs a signal to the control center 3. When the gas pressure inside the cladding chamber 2 is lower than the set value, the control center 3 outputs a signal to the vacuum pump 6 to shut it down. In this invention, the vacuum pump 6 is shut down when the gas pressure is below 100 Pa. Next, the control center 3 outputs a signal to open the pressure reducing valve on the inert gas cylinder 4, allowing inert gas to be injected into the cladding chamber 2. When the gas pressure inside the cladding chamber 2 reaches the standard atmospheric pressure, the control center outputs a signal to close the pressure reducing valve on the inert gas cylinder 4. Then, control center 3 restarts vacuum pump 6 to begin evacuating chamber 2. The above evacuation and inert gas filling operations are repeated 3 to 5 times to ensure that the entire cladding process is carried out in a high concentration of inert gas atmosphere to prevent oxidation of the coating at high temperatures.

[0063] Step 3: The control center 3 outputs a signal to the first telescopic motor 23 on the longitudinal front side. The first telescopic motor 23 drives the first telescopic rod 24 to push the workpiece 17 to be processed to the rear side. At the same time, the control center 3 outputs a signal to the powder spreader 20. The powder spreader 20 and the first telescopic rod 24 work simultaneously. During the process of the workpiece 17 moving to the rear side, the powder spreader 20 spreads the coating powder 18 on the upper surface of the workpiece 17. At the same time, the scraper 21 spreads the coating powder 18 evenly. The thickness of the coating powder 18 is 2-3 mm.

[0064] When the coating powder 18 is spread on the workpiece 17, the workpiece 17 is pushed by the first telescopic rod 24 to the position directly below the perforated graphite felt 19. At this time, the first distance sensor 22 detects the position of the workpiece 17, and the control center 3 controls the first telescopic motor 23 on the longitudinal front side to return to the initial position and controls the powder spreader 20 to stop working.

[0065] Step 4: The control center 3 outputs a signal to the two second telescopic motors 11. The two second telescopic motors 11 drive the second telescopic rods 12 on both sides to push the boron nitride baffles 13 on both sides towards the workpiece 17 simultaneously, until the boron nitride baffles 13 contact the workpiece 17. At this time, the second distance sensor 10 detects the lateral position of the boron nitride baffles 13 towards the workpiece 17 and outputs a signal to the control center 3. The process continues until the workpiece 17 is engaged in the groove of the boron nitride baffles 13. The control center 3 then outputs a signal to the second telescopic motors 11, and the second telescopic motors 11 stop working. During this process, the advancing speed of the second telescopic rods 12 is generally 50–500 mm / s.

[0066] Step 5: Control center 3 outputs a signal to the third telescopic motor 15, which drives the third telescopic rod 16 to raise the workpiece 17, causing the coating powder 18 to approach the perforated graphite felt 19, but without contact. At this time, the third distance sensor 14 continuously monitors the distance between the coating powder 18 and the perforated graphite felt 19 and outputs a signal to control center 3. To ensure the ultrasonic vibrating head 8 refines the grains of the coating powder 18, a certain gap (20-30mm) is maintained between the perforated graphite felt 19 and the coating powder 18. When the distance between the coating powder 18 and the perforated graphite felt 19 is 20-30mm, control center 3 outputs a signal to the third telescopic motor 15, which stops operating, and the third telescopic rod 16 remains in this position.

[0067] Step Six: Control Center 3 controls the ultrasonic generator 5 to operate. When the ultrasonic generator 5 is operating, the coating powder 18 does not contact the coating; instead, air is used as a carrier to transmit ultrasonic vibrations to the cladding layer. The workpiece 17 itself does not vibrate. The ultrasonic generator 5 has an output power of 700W, generating vibrations of 35kHz and 4µm. After waiting 3 minutes for the ultrasonic vibration head 8 to stabilize, cladding is performed.

[0068] Step 7: Control center 3 outputs a signal to turn on DC power supply 1. DC power supply 1, through graphite felt fixture 9, allows current to flow evenly through the porous graphite felt 19. The transient high current generated by the porous graphite felt 19 causes the coating powder 18 to bond with the workpiece 17, forming a cladding layer. At this time, temperature sensor 26 monitors the temperature of the cladding layer in real time. When the temperature is below 1000℃, the maximum output power of ultrasonic vibrator 8 is 700W, and the maximum current density through the porous graphite felt 19 is 3.5*10⁻⁶. 5 A / m 2 When the temperature rises above 1000℃, the maximum output power of the ultrasonic vibrating head 8 is 1000W, and the maximum current density through the graphite felt 19 is 7.5*10. 5 A / m 2At this time, the temperature of the perforated graphite felt 19 rapidly reaches about 3000℃, and is maintained for 20-30 seconds for cladding of the workpiece 17.

[0069] Step 8: Control center 3 turns off DC power supply 1, ultrasonic vibrating head 8 continues to work, and ultrasonic vibrating head 8 stops working after the cladding layer cools down to below 800℃, thus completing the cladding of workpiece 17.

[0070] Step 9: After the cladding is completed, the third telescopic motor 15 drives the third telescopic rod 16 to continue moving upward, thereby driving the cladding layer of the workpiece 17 to impact the ultrasonic vibrating head 8, forging the cladding layer to produce plastic deformation, removing the original defects such as segregation, porosity, air holes, and slag inclusions in the cladding layer, making its structure more compact, and further improving the plasticity and mechanical properties of the cladding layer.

[0071] Step 10: After forging is completed and the cladding layer temperature drops to room temperature, the third telescopic motor 15 drives the third telescopic rod 16 to descend, and the workpiece 17 to be processed follows to its original position. Then, the first telescopic motor 23 on the longitudinal rear side works, driving the first telescopic rod 24 to push the workpiece 17 to its initial position, and the workpiece 17 can be taken out by opening the box door.

Claims

1. An ultrasonic vibration-assisted global transient cladding device, comprising a cladding box (2), characterized in that: The cladding box (2) is equipped with an inert gas cylinder (4), an ultrasonic generator (5), and a vacuum pump (6) on the outside. Inside the cladding box (2), from top to bottom, are an ultrasonic vibrating head (8), a perforated graphite felt (19), a coating powder (18), a workpiece to be processed (17), and a third telescopic motor (15). The top surface of the workpiece to be processed (17) is covered with a layer of coating powder (18). Multiple ultrasonic vibrating heads (8) are arranged vertically, and the perforated graphite felt (19) is arranged horizontally with through holes. The number of ultrasonic vibrating heads (8) is the same as the number of perforated graphite felt (19). The perforated graphite felt (19) has the same number of holes, and an ultrasonic vibrating head (8) extends into one hole of the perforated graphite felt (19); multiple ultrasonic vibrating heads (8) are connected to an ultrasonic generator (5) outside the cladding box (2) via control lines; on each side of the perforated graphite felt (19) is a graphite felt clamp (9) made of conductive metal material, and the graphite felt clamp (9) is connected to a DC power supply (1) outside the cladding box (2); on each side of the workpiece to be processed (17) is a boron nitride baffle (13), and the boron nitride baffle (13) is... 3) The boron nitride baffle (13) is slidably connected to both sides of the workpiece (17) to be processed. The bottom of the boron nitride baffle (13) is slidably connected to the bottom surface of the cladding box (2). The top of the boron nitride baffle (13) is fixedly supported by the graphite felt fixture (9). A horizontally arranged second telescopic motor (11) is set between the lateral side of each boron nitride baffle (13) and the inner side wall of the cladding box (2). The output end of the second telescopic motor (11) is coaxially fixedly connected to the second telescopic rod (12). One second telescopic rod (12) is fixedly connected to one boron nitride baffle (13). A third telescopic motor (15) is arranged vertically upward between the bottom of the part (17) and the bottom of the cladding box (2). The output end of the third telescopic motor (15) can drive the part (17) to be processed through the third telescopic rod (16). Along the longitudinal direction of the cladding box (2), a first telescopic motor (23) is arranged horizontally on both the front and rear sides of the part (17) to be processed. The output end of the first telescopic motor (23) can drive the part (17) to be processed to move through the first telescopic rod (24). A powder spreader (20) is provided in front of the ultrasonic vibration head (8) in the longitudinal direction.

2. The ultrasonic vibration-assisted full-domain transient cladding device according to claim 1, characterized in that: The control center (3) is fixedly connected to the side wall of the cladding box (2). The control center (3) controls the DC power supply (1), inert gas cylinder (4), ultrasonic generator (5), vacuum pump (6), powder spreader (20), first telescopic motor (23), second telescopic motor (11) and third telescopic rod (16) respectively via control lines.

3. The ultrasonic vibration-assisted global transient cladding device according to claim 2, characterized in that: The cladding box (2) is equipped with distance sensors that detect the horizontal, vertical and vertical positions of the workpiece (17) to be processed, as well as a vacuum sensor (25) for detecting the vacuum level inside the cladding box (2). All sensors are connected to the control center (3) via signal lines.

4. A cladding method using the ultrasonic vibration-assisted full-domain transient cladding device according to any one of claims 1-3, characterized in that: Includes the following steps: Step 1: The coating powder (18) is placed in the powder spreader (20). The workpiece (17) is initially positioned below the powder spreader (20). The vacuum pump (6) first evacuates the gas in the cladding box (2), and then the inert gas cylinder (4) is opened to inject inert gas into the cladding box (2). Step 2: The first telescopic motor (23) pushes the workpiece (17) to move to the rear side, and at the same time the powder spreader (20) spreads the coating powder (18) on the upper surface of the workpiece (17). When the coating powder (18) is spread, the workpiece (17) is pushed by the first telescopic rod (24) to the bottom of the perforated graphite felt (19). The first telescopic motor (23) returns to the initial position and controls the powder spreader (20) to stop working. Step 3: When the two second telescopic motors (11) simultaneously push the boron nitride baffles (13) on both sides to contact the workpiece (17), the second telescopic motors (11) stop working; Step 4: The third telescopic motor (15) drives the workpiece (17) to be processed to be raised upwards, and the coating powder (18) is close to the perforated graphite felt (19) but not in contact with it. The third telescopic motor (15) stops and remains in this position. Step 5: The ultrasonic generator (5) is working. After the ultrasonic vibrating head (8) vibrates and stabilizes, the DC power supply (1) is turned on. The transient heat generated by the perforated graphite felt (19) causes the coating powder (18) to combine with the workpiece (17) to form a cladding layer. Step 6: After the cladding layer is formed, turn off the DC power supply (1), and the ultrasonic vibrating head (8) continues to work. After the cladding layer cools down, the ultrasonic vibrating head (8) stops working. Step 7: The third telescopic motor (15) continues to move upward, driving the cladding layer of the workpiece (17) to impact the ultrasonic vibrating head (8) and forging the cladding layer; Step 8: After forging is completed, the cladding layer is cooled to room temperature. The third telescopic motor (15) descends, and the workpiece (17) is lowered to its original position. The first telescopic motor (23) on the longitudinal rear side drives the workpiece (17) to its initial position.

5. The cladding method according to claim 4, characterized in that: The workpiece (17) to be processed is first ultrasonically cleaned with alcohol and then dried, and then sandblasted on the surface of the workpiece (17).

6. The cladding method according to claim 4, characterized in that: The coating powder (18) is placed in a vacuum drying oven for drying at a temperature of 100°C for 3 to 5 hours. The coating powder (18) can be any kind of hard alloy powder.

7. The cladding method according to claim 4, characterized in that: In step one, when the gas pressure inside the cladding box (2) is lower than 100 Pa, the vacuum pump (6) is turned off; when the gas pressure inside the cladding box (2) reaches the standard atmospheric pressure, the inert gas cylinder (4) is turned off; then the vacuum pump (6) is started again to evacuate the vacuum, and the operation of evacuating the vacuum and filling the inert gas is repeated 3 to 5 times.

8. The cladding method according to claim 4, characterized in that: In step four, the gap between the porous graphite felt (19) and the coating powder (18) is 20-30 mm.

9. The cladding method according to claim 4 is characterized in that: in step five: the output power of the ultrasonic generator (5) is 700W, generating vibrations of 35kHz and 4µm, and the ultrasonic vibrating head (8) vibrates stably after waiting for 3 minutes.

10. The cladding method according to claim 4, characterized in that: When the temperature of the cladding layer is below 1000℃, the output power of the ultrasonic vibrating head (8) is 700W, and the maximum current density through the porous graphite felt (19) is 3.5*10. 5 A / m 2 When the temperature rises above 1000℃, the maximum output power of the ultrasonic vibrating head (8) is 1000W, and the maximum current density through the porous graphite felt (19) is 7.5*10. 5 A / m 2 The temperature of the perforated graphite felt (19) reaches 3000℃ and is held for 20-30 seconds to coat the workpiece (17).

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