Preparation method and system of low-plasticity high-temperature alloy welding wire

Abstract

The invention discloses a preparation method of a low-plasticity high-temperature alloy welding wire, and belongs to the technical field of welding wire preparation. Comprising the following steps: S1, preparing a metal thin tube sheath with a sealed first end; s2, the metal thin tube sheath is filled with high-temperature alloy powder; s3, carrying out vacuum degassing treatment on the metal thin tube sheath, and welding and sealing the second end; s4, the sealed thin metal tube sheath is put into hot isostatic pressing equipment to be sintered, and a near-net-shaped wire is obtained; and S5, removing the metal thin tube sheath of the obtained near-net-shaped wire through a chemical corrosion or centerless grinding process to obtain the target high-temperature alloy welding wire. The welding wire for repairing the high-pressure turbine blade has the advantages of low cost, short period and high efficiency in preparation of the welding wire for repairing the high-pressure turbine blade. In addition, the invention further discloses a preparation system of the welding wire, and the preparation system comprises a sheath preparation device, a powder filling device, a vacuum sealing device, hot isostatic pressing equipment, a transmission mechanism, a sheath removal device and a central control unit.

Description

Technical Field

[0001] The present invention relates to the technical field of wire preparation, and in particular to a method and system for preparing a low-plasticity superalloy wire. Background Art

[0002] In the field of aerospace, as a key component of an aeroengine, a high-pressure turbine blade is in a working environment of high temperature, high pressure and high rotational speed for a long time, and is extremely prone to damage. Welding repair technology is an important means to ensure the service life of high-pressure turbine blades and reduce production costs. As a key consumable material in the welding process, the performance and quality of the wire directly affect the welding repair effect. At present, the wire used for welding repair of high-pressure turbine blades faces many problems. From the perspective of the preparation process, the traditional drawing process requires the material to have good plasticity. However, the existing wire used for repairing high-pressure turbine blades has poor plasticity, and it is difficult to prepare a fine wire with a diameter less than 1.2 mm through the conventional drawing process. Although the horizontal continuous casting process has solved the preparation problem of some wires to a certain extent, it can only prepare wires with a diameter greater than 2 mm. In actual application scenarios, for some precision welding parts, a fine wire (diameter less than 1.2 mm) is the key to ensuring welding quality and precision, and the existing preparation process cannot meet this requirement. In terms of foreign patents, for example: the patent with the patent number "US6904657B2" and the name "Method and apparatus for extruding brittle metal wire", when dealing with "wire and other slender parts of high-performance brittle alloys (such as aerospace welding materials)", the "blank can preparation - filling - exhaust - extrusion - cutting" process is adopted, which is essentially a method for manufacturing fine wires by extrusion. This method has complex processes and involves multiple processing links, which not only increases the production cycle, but also requires professional equipment and strict process control for each link, resulting in high costs. In China, the relevant technology started relatively late, and the research and production capabilities in the field of preparing high-temperature alloy wires for repairing high-pressure turbine blades are relatively weak, and currently mainly rely on imports. Imported wires have many disadvantages. On the one hand, the cost is high, which greatly increases the production costs of aerospace and other enterprises; on the other hand, the import cycle is long, and it often takes several months from placing an order to receiving the goods, seriously affecting the production progress and maintenance efficiency of enterprises. Summary of the Invention

[0003] In order to overcome the above-mentioned problems of the prior art, the present invention aims to provide a method for preparing a low-plasticity superalloy wire with simple processes, short production cycle and low cost. In addition, the present invention also provides a preparation system for the above-mentioned low-plasticity superalloy wire.

[0004] To achieve the above object, the present invention adopts the following technical solutions: A method for preparing a low-plasticity superalloy wire, comprising the following steps: S1. Prepare a metal fine tube sheath, with the first end of the metal fine tube sheath sealed; S2. Fill the high-temperature alloy powder into the metal fine tube sheath; S3. Perform vacuum degassing treatment on the filled metal fine tube sheath and weld and seal the second end; S4. Place the sealed metal fine tube sheath into a hot isostatic pressing equipment for sintering to obtain a near-net-shaped wire; wherein: the near-net-shaped wire refers to a semi-finished wire whose dimensional accuracy and shape are close to the requirements of the target high-temperature alloy welding wire after hot isostatic pressing sintering, and the internal structure is uniform, without obvious pores, cracks and other defects; S5. Remove the metal fine tube sheath of the obtained near-net-shaped wire by chemical corrosion or centerless grinding or a combination of both processes to obtain the target high-temperature alloy welding wire.

[0005] Preferably: the inner diameter of the metal fine tube sheath is 1.2 - 2.0 mm, and the wall thickness is 0.3 - 1.0 mm.

[0006] Preferably: the vacuum degree after the vacuum pumping treatment is ≤ 4.0×10 -2 Pa, and resistance welding or argon arc welding is used for welding and sealing.

[0007] Preferably: the specific process parameters of the hot isostatic pressing sintering are: sintering pressure 100 - 180 MPa, sintering temperature 1100 - 1250 °C, and heat preservation and pressure holding time 2 - 5 hours.

[0008] Preferably: the chemical corrosion process uses an acidic corrosion solution, including but not limited to a sulfuric acid - hydrochloric acid mixed solution.

[0009] A preparation system for a low-plasticity high-temperature alloy welding wire, comprising: A sheath preparation device for preparing a metal fine tube sheath with one end sealed, and the material of the metal fine tube sheath is stainless steel or carbon steel pipe; A powder filling device for filling the high-temperature alloy powder into the metal fine tube sheath; A vacuum sealing device, including a vacuum pump and a welding device, for performing vacuum degassing and sealing welding on the filled metal fine tube sheath; A hot isostatic pressing equipment for sintering the sealed metal fine tube sheath, and the hot isostatic pressing equipment provides a sintering pressure of 100 - 180 MPa, a sintering temperature of 1100 - 1250 °C and a heat preservation and pressure holding time of 2 - 5 hours; A transmission mechanism for transmitting the sintered and cooled wire to the sheath removal device to avoid residual stress; A sheath removal device, including a chemical corrosion tank or a centerless grinder or a combined device thereof, for removing the metal fine tube sheath of the sintered wire; A central control unit, communicatively connected to the sheath preparation device, the powder filling device, the vacuum sealing device, the hot isostatic pressing equipment, and the sheath removal device; the central control unit is configured to: a. Synchronously control the start-stop and operation timing of each device according to preset process parameters; b. Receive real-time data from the temperature sensor and pressure sensor in the hot isostatic pressing equipment, and dynamically adjust the sintering pressure, temperature, and holding pressure time to make the deviation between the actual process parameters and the preset value less than the preset deviation value; c. After the vacuum sealing device evacuates to the preset value, automatically trigger the welding equipment to complete the sealing; d. After the hot isostatic pressing sintering is completed, transfer the wire cooled to the preset value to the sheath removal device through the transfer mechanism, and start the sheath removal device to remove the sheath.

[0010] Preferably: The sheath preparation device includes a pipe cutting device and an end sealing device, and the end sealing device is used for necking or welding and sealing one end of the metal capillary.

[0011] Preferably: The powder filling device includes a weighing device and a filling device. The weighing device is used to weigh the weight of the superalloy powder to be filled, and the filling device is used to fill the metal capillary sheath with the specified weight of superalloy powder.

[0012] In view of the manufacturing problem of low-plasticity wire materials that "the plastic deformation of the welding repair wire for high-pressure turbine blades is poor, the forming is difficult, and it cannot be prepared by conventional drawing processes", the present invention directly sintered near-net-shaped wire materials through a hot isostatic pressing preparation process, and then removed the capillary sheath. By accurately controlling the removal time, the required welding wire is obtained, which has obvious advantages compared with the prior art. Specifically as follows: 1. Process simplification and cost reduction: Compared with the complex process of first casting or powder sintering a thick bar and then hot extruding abroad, the present invention adopts the method of directly sintering near-net-shaped wire materials by hot isostatic pressing, reducing intermediate processing links, eliminating the need to purchase multiple sets of professional equipment, reducing equipment costs and production energy consumption, effectively shortening the production cycle, and thus significantly reducing the preparation cost of the welding wire.

[0013] 2. Excellent performance: The hot isostatic pressing process can make the alloy powder fully sinter and densify under high temperature and high pressure. The prepared welding wire has uniform composition, uniform and dense structure, and stable performance. When used for welding repair of high-pressure turbine blades, it can effectively improve the welding quality and ensure that the repaired blades have good mechanical properties and reliability.

[0014] 3. Breaking the import dependence and ensuring the supply chain security: The present invention realizes the domestic preparation of low-plasticity superalloy welding wires, can replace imported products, reduces the enterprise's dependence on imported welding wires, solves the risk problem of the key material supply chain, and has important significance for ensuring the stable development of China's aerospace industry. Description of the Drawings

[0015] Figure 1 is the preparation flow chart; Figure 2 is the metallographic structure diagram of the obtained welding wire; Figure 3 is the physical diagram of the obtained welding wire; Figure 4 is the block diagram of the sintering system in Example 2.

[0016] In the figure: 1. Metal fine tube sheath; 2. Nickel-based superalloy powder; 3. Welding wire. Specific implementation manners

[0017] The method and principle of the present invention will be fully elaborated in combination with specific embodiments, so that those of ordinary skill in the art can fully understand and implement it. Example 1

[0018] As Figure 1 shown is the preparation flow chart of this embodiment. Specifically as follows: This embodiment discloses a method for preparing a low-plasticity superalloy welding wire, including the following steps: S1. Prepare a metal fine tube sheath and seal the first end; Select a metal fine tube sheath (made of stainless steel, inner diameter 1.5 mm, sheath wall thickness 0.5 mm), cut the metal fine tube sheath with the required length through a metal tube cutting machine, and seal the first end through an end sealing device to form a cavity for accommodating superalloy powder. The superalloy powder in this embodiment is a nickel-based superalloy. This step provides a closed environment to avoid powder oxidation; by controlling the size of the metal fine tube sheath, the final wire diameter accuracy is ensured within the control range, preparing for subsequent processes.

[0019] S2. Fill the superalloy powder; Fill the nickel-based superalloy powder into the metal fine tube sheath evenly through vibration, and the filling density reaches 60%-80% of the theoretical value; powder particle size: 50-160 μm. Through this step, it can be ensured that the powder is evenly distributed in the tube, reducing internal defects after sintering, and avoiding uneven shrinkage during subsequent sintering by controlling the powder particle size.

[0020] S3. Vacuum degas the metal fine tube sheath and seal the second end; Place the metal fine tube sheath filled with alloy powder in a vacuum welding cavity (integrated welding electrodes), evacuate it to the target vacuum degree through a vacuum pump group, and then seal the second end through welding to achieve the overall sealing effect of the metal fine tube sheath; through this step, the gas adsorbed on the powder surface, the voids between the powders and in the sheath can be eliminated, preventing oxidation or pores during the sintering process.

[0021] S4. Hot isostatic pressing sintering (HIP); Put the sealed metal capillary sleeve into the HIP equipment, apply isotropic pressure to the metal capillary sleeve, and apply high temperature at the same time. Under the action of high temperature and high pressure, the powder is completely sintered and densified. Among them, the temperature is 1200 °C, the pressure is 180 Mpa, the heat preservation time is 3 hours, and the protective gas is argon. After reaching the time, cool the furnace to below 300 °C and take it out for air cooling. The specific process of the process is: put the sleeve into the furnace - evacuate - fill the furnace with argon at a specified pressure - heat to the specified temperature at (3 °C - 15 °C) / min - keep the temperature and pressure for 3 hours - furnace cooling - take it out for air cooling below 300 °C;; After multiple test comparisons, using the above process and parameters can better sinter and densify the alloy powder, and improve the stability and consistency of the wire rod structure and performance.

[0022] S5. Remove the metal capillary sleeve; Immerse the HIP-treated metal capillary sleeve in the acid solution until the metal capillary sleeve is completely dissolved. In this embodiment, 40% sulfuric acid + 3% hydrochloric acid is selected, and the time is 25 minutes.

[0023] As Figure 2 、 Figure 3 shown, it is the wire rod metallographic structure diagram and physical diagram obtained by the above method. It can be clearly seen that the obtained wire rod has no defects such as pores and cracks; there is no sleeve residue on the surface of the wire rod, the wire rod composition is pure and uniform, and the final diameter is 1 mm, meeting the requirements for turbine blade repair.

[0024] In addition, through the above method, 100 metal capillary sleeves are selected for wire rod preparation experiments. The obtained wire rods all meet the requirements of "high-pressure turbine blade welding repair", and their diameter error ≤ 0.05 mm; the wire rod density ≥ 99.5%.

[0025] In this embodiment, the required wire rod is obtained by hot isostatic pressing near net shape, replacing the multi-process processing of traditional "casting + hot extrusion", greatly simplifying the preparation process and improving the preparation efficiency. In addition, the process of metal sleeve and chemical corrosion elimination makes the sleeve residue easier to control and more thoroughly removed, and is less likely to damage the alloy wire rod compared with grinding.

[0026] Preferably: the vacuum degree after vacuum treatment ≤ 4.0×10 -2 Pa, and resistance welding or argon arc welding is used for welding and sealing.

[0027] Preferably: the specific process parameters of the hot isostatic pressing sintering are: sintering pressure 150 MPa, sintering temperature 1180 °C, heat preservation and pressure holding time 4 hours. Example 2

[0028] As Figure 4As shown in the figure, the hot isostatic pressing sintering system disclosed in this embodiment includes a sheath preparation device, a powder filling device, a vacuum sealing device, a hot isostatic pressing equipment, a transmission mechanism, a sheath removal device, and a central control unit. Each device realizes linkage control through the central control unit, and its communication interface is connected to the sensors and actuators (such as servo motors, vacuum pump valves, heating elements, etc.) of each device. The central control unit has a process parameter database built-in, which can store multiple sets of preset parameters (such as pressure, temperature, time, etc.), and receives operation instructions through a human-machine interaction interface.

[0029] The specific descriptions of each device are as follows: The sheath preparation device is used to prepare a metal capillary sheath with one end sealed, and the material of the metal capillary sheath is stainless steel or carbon steel pipe; The powder filling device is used to fill low-plasticity superalloy powder into the metal capillary sheath; The vacuum sealing device includes a vacuum pump and a welding device, and is used to perform vacuum degassing and sealed welding on the filled metal capillary sheath; The hot isostatic pressing equipment is used to sinter the sealed metal capillary sheath. The hot isostatic pressing equipment provides a sintering pressure of 100 - 180 MPa, a sintering temperature of 1100 - 1250 °C, and a heat preservation and pressure holding time of 2 - 5 hours; The transmission mechanism is used to transfer the wire after sintering and cooling to the target temperature (below 50 °C to avoid residual stress in the wire affecting its performance) to the sheath removal device (the transmission method can be selected as: transmitted through a conveyor belt controlled by a PLC); The sheath removal device includes a chemical corrosion tank or a centerless grinder, and is used to remove the metal capillary sheath of the sintered wire; The central control unit is communicatively connected to the sheath preparation device, the powder filling device, the vacuum sealing device, the hot isostatic pressing equipment, the transmission mechanism, and the sheath removal device; the central control unit is configured as follows: a. Synchronously control the start, stop, and operation timing of each device according to the preset process parameters; b. Receive the real-time data of the temperature sensor and pressure sensor in the hot isostatic pressing equipment, and dynamically adjust the sintering pressure, temperature, and heat preservation and pressure holding time to make the deviation between the actual process parameters and the preset value less than the preset value; c. Automatically trigger the welding device to complete the sealing after the vacuum sealing device evacuates to the preset value; d. After the hot isostatic pressing sintering is completed, transfer the wire cooled to the preset value to the sheath removal device through the transmission mechanism, and start the sheath removal device to remove the sheath.

[0030] Among them: The sheath preparation device includes a pipe cutting device and an end sealing device, and the end sealing device is used to perform necking or welding and sealing on one end of the metal capillary. The powder filling device includes a weighing device and a filling device. The weighing device is used to weigh the weight of the superalloy powder to be filled, and the filling device is used to fill the metal capillary sheath with the superalloy powder of the specified weight.

[0031] The specific working process is as follows: ⑴. After the central control unit receives the operation instruction, it starts the sheath preparation device, drives the cutting tool through the servo motor, and cuts the metal capillary to the preset length; the cut metal tube is sent to the end sealing device, and the first end is sealed by argon arc welding or laser welding; after sealing, the air tightness is checked. If there is air leakage, an alarm is triggered and the process is paused. ⑵. Start the powder filling device, link the weighing device and the filling device, and monitor the filling amount in real time through the weighing device to ensure that the powder filling density of each sheath meets the requirements. The filling is completed in an inert gas (such as argon) environment, and the gas flow rate is adjusted by the central control unit. ⑶. The filled sheath is transported to the vacuum sealing device, and the central control unit performs the following steps: Vacuum pumping: Start the vacuum pump and monitor the vacuum degree in real time through the vacuum gauge. Sealing trigger: When the vacuum degree reaches the standard, automatically trigger the resistance welding or argon arc welding program to seal the second end of the sheath. Sealing quality detection: Detect the sealed weld by a helium mass spectrometer leak detector, and mark and reject the unqualified products. ⑷. The sealed sheath is transferred to the hot isostatic pressing device, and the central control unit starts the sintering program: Parameter initialization: Call the preset process parameters. Dynamic adjustment: Temperature control - Collect temperature data in real time through the thermocouple, and adjust the power of the heating element using the PID algorithm to keep the temperature fluctuation below the preset value. Pressure control: Monitor the pressure through the piezoelectric sensor, and the hydraulic system dynamically compensates for the pressure deviation to ensure that the pressure fluctuation is below the preset value. Abnormal handling: If the temperature or pressure exceeds the limit, trigger an emergency stop and alarm. ⑸. After sintering is completed, the central control unit starts the transmission mechanism: Transfer the cooled wire to the removal device, and transfer the wire to the sheath removal device through the robotic arm. ⑹. The central control unit selects the removal process according to the sheath material: Chemical corrosion (stainless steel sheath): Inject a sulfuric acid-hydrochloric acid mixture into the chemical corrosion tank, and control the liquid temperature at 40 - 50 °C. The corrosion time is calculated by the central control unit (for example, 1 - 2 hours), and the waste liquid is automatically discharged and the wire is rinsed after corrosion. Centerless grinding (carbon steel sheath): Start the centerless grinding machine, the grinding wheel speed is 2000 - 3000 rpm, and the feed rate is 0.1 - 0.3 mm / s. Monitor the wire diameter in real time through the laser diameter gauge until the target size is reached (for example, 1 mm ± 0.05 mm). In addition, according to different sheath materials and the target wire diameter size, a chemical corrosion-centerless grinding combination method can be adopted, and the process is controlled by time to achieve the target wire diameter size.

[0032] In addition, the central control unit stores the whole process data (temperature, pressure, time, etc.), supporting the traceability of process parameters and quality analysis. A unique ID is generated for each batch of welding wire, which is associated with the production log and inspection report.

[0033] The above embodiments are only the preferred embodiments of the present invention and do not impose any formal limitations on the present invention. Any person skilled in the art can, without departing from the technical principle and scope of the present invention, make many possible changes and modifications to the technical solution of the present invention by using the methods disclosed above, or modify it into equivalent embodiments with equivalent changes. Therefore, any combination, modification or replacement of the technical features disclosed in the present invention made in accordance with the technical essence of the present invention without departing from the principle or scope of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A preparation method of a low-plasticity superalloy welding wire, characterized in that, It includes the following steps: S1. Prepare a metal capillary sheath made of stainless steel or carbon steel pipe, and seal the first end of the metal capillary sheath; S2. Fill the high-temperature alloy powder into the metal capillary sheath; S3. Perform vacuum degassing treatment on the filled metal capillary sheath and weld and seal the second end; S4. Place the sealed metal capillary sheath into a hot isostatic pressing device for sintering to obtain a near-net-shaped wire; S5. Remove the metal capillary sheath of the obtained near-net-shaped wire through chemical etching, centerless grinding or a combination of both processes to obtain the target high-temperature alloy welding wire.

2. The preparation method of the low-plasticity superalloy welding wire according to claim 1, characterized in that The inner diameter of the metal capillary sheath is 1.2 - 2.0 mm, and the wall thickness is 0.3 - 1.0 mm.

3. The preparation method of the low-plasticity superalloy welding wire according to claim 2, wherein, The vacuum degree after the evacuation treatment ≤ 4.0×10 -2 Pa, and resistance welding or argon arc welding is used for welding and sealing.

4. The method for preparing a low-plasticity superalloy welding wire according to claim 3, wherein, The specific process parameters of the hot isostatic pressing sintering are: sintering pressure 100 - 180 MPa, sintering temperature 1100 - 1250 °C, and heat preservation and pressure holding time 2 - 5 hours.

5. The method for preparing a low-plasticity superalloy welding wire according to any one of claims 1 to 4, characterized in that, The chemical etching process uses an acidic etching solution, including but not limited to a sulfuric acid-hydrochloric acid mixed solution.

6. A preparation system for a low-plasticity superalloy welding wire, characterized in that, It includes: A sheath preparation device for preparing a metal capillary sheath with one end sealed, and the metal capillary sheath is made of stainless steel or carbon steel pipe; A powder filling device for filling the high-temperature alloy powder into the metal capillary sheath; A vacuum sealing device, including a vacuum pump and a welding device, for performing vacuum degassing and seal welding on the filled metal capillary sheath; A hot isostatic pressing device for sintering the sealed metal capillary sheath, and the hot isostatic pressing device provides a sintering pressure of 100 - 180 MPa, a sintering temperature of 1100 - 1250 °C, and a heat preservation and pressure holding time of 2 - 5 hours; A transmission mechanism for conveying the sintered and cooled wire to the sheath removal device to avoid residual stress; A sheath removal device, including a chemical etching tank, a centerless grinding machine or a combined device thereof, for removing the metal capillary sheath of the sintered wire; A central control unit is communicatively connected to the sheath preparation device, the powder filling device, the vacuum sealing device, the hot isostatic pressing device, the transmission mechanism and the sheath removal device; the central control unit is configured as: a. Synchronously control the start-stop and operation timing of each device according to preset process parameters; b. Receive the real-time data of the temperature sensor and pressure sensor in the hot isostatic pressing device, dynamically adjust the sintering pressure, temperature and heat preservation and pressure holding time, so that the deviation between the actual process parameters and the preset value is less than the preset deviation value; c. After the vacuum sealing device evacuates to the preset value, automatically trigger the welding device to complete the sealing; d. After the hot isostatic pressing sintering is completed, convey the wire cooled to the preset value to the sheath removal device through the transmission mechanism, and start the sheath removal device to remove the sheath.

7. The low-plasticity superalloy welding wire preparation system according to claim 6, wherein, The sheath preparation device includes a pipe cutting device and an end sealing device, and the end sealing device is used for necking or welding and sealing one end of the metal capillary.

8. The low-plasticity superalloy welding wire preparation system according to claim 7, characterized in that The powder filling device includes a weighing device and a filling device, the weighing device is used for weighing the weight of the high-temperature alloy powder to be filled, and the filling device is used for filling the specified weight of the high-temperature alloy powder into the metal capillary sheath.

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