Electron beam remelting repairing method suitable for tungsten-based material part
Through the electron beam remelting repair method, the inconsistent components and high cost problems of damage repair in complex environments of tungsten-based material components are solved, and efficient and accurate repair results are achieved, meeting the long-term service needs of tungsten-based material components.
Patent Information
- Application Number
- CN202411420415.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-12
- Publication Date
- 2025-01-03
AI Technical Summary
Tungsten-based material components are prone to wear, peeling, cracking and other problems in complex service environments. The existing repair technology cannot meet its high performance needs. The introduction of different materials leads to inconsistent components, which has high repair costs and low efficiency, making it difficult to achieve long-term service and Engineering application standards.
The electron beam remelting repair method is adopted to form a material filling cavity by fine processing of damaged parts, filling the tungsten block with adapted tungsten block, and using high-energy electron beam to scan the surface of the tungsten block at a high frequency cyclic surface along a specific scanning trajectory to realize the tungsten block The uniform remelting and metallurgy combination with the matrix avoids oxidation and splashing, ensuring consistency and high efficiency of repair interface.
Without introducing additional heterogeneous materials, the high bonding strength and fatigue resistance of tungsten-based material components are achieved, the repair range is wide, the cost and time is significantly reduced, the oxidation and splashing problems are avoided, the repair efficiency and accuracy are improved, and the repairing efficiency and accuracy are met. Long-term service standard for tungsten-based material components.
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Figure CN119237895A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of damaged refractory metal repair, and in particular relates to an electron beam remelting repair method suitable for tungsten-based material parts. Background Art
[0002] Tungsten-based material components have a very unique industry position in the fields of nuclear industry, aerospace, and medical health due to their many excellent properties such as high melting point, high thermal conductivity, and stable chemical properties, such as fusion reactor divertors, aircraft surface shielding layers, and medical radiation shielding panels. However, the service environment of tungsten-based material components is relatively complex and harsh. They are affected by multiple effects such as repeated thermal stress shocks, energy deposition, multiple irradiation, and particle scouring, and are inevitably prone to wear, peeling, cracks, and even collapse and defects, leading to failure. Since such components are expensive, replacement is inefficient and costly, and accompanied by a large amount of material waste, it is difficult to maintain the long-term healthy and sustainable development of the equipment by directly replacing damaged components. Reliable repair technology is urgently needed to restore its geometric integrity and microstructural integrity, significantly reduce life cycle costs, and achieve sustainable use of resources.
[0003] At present, the repair technology of tungsten-based material parts can be roughly divided into: (1) Traditional repair, which usually involves a combination of cleaning and flaw detection, welding / machining, grinding and polishing post-processing, etc., and brazing is often used to connect a new piece of tungsten (or tungsten alloy). However, due to the fundamental limitations of its own strategies and application tools, there are often problems such as difficult to control the heat-affected zone, poor strength and fatigue resistance of the joint, poor flexibility, and limited repair range. The repair quality is difficult to meet the high-performance requirements of tungsten-based material parts in service. In addition, the introduction of additional dissimilar connecting materials (such as brazing filler metals, etc.) destroys the originality and consistency of the components, which is bound to cause additional impact on the overall operation of the components; (2) New repair, represented by the continuously developing and mature additive manufacturing technology, through the melting and deposition of tungsten powder, the complete part is rebuilt layer by layer at the damaged part after treatment. However, tungsten powder is expensive and difficult to obtain. For different high-energy heat sources, high-quality powders of different particle sizes need to be prepared to achieve the ideal melting effect. The process is complicated and the repair efficiency is low. In addition, during actual repair, there are often problems such as oxide aggregation and powder splashing. Especially for edge damage, the melt is difficult to effectively adhere, resulting in uneven and uneven deposition layers. The above measures cannot meet the long-term service and engineering application standards of tungsten-based material components.
[0004] In order to reduce the life cycle cost of tungsten-based material parts, it is necessary to develop a new repair method. Without introducing dissimilar materials (such as brazing filler metals and other repair agents), the repair material and the matrix are promoted to form a good metallurgical bond to ensure consistency before and after the repair; simplify the process difficulty and number of steps from obtaining the repair raw materials to restoring the performance of the parts, reduce the repair cost, and improve the repair efficiency; avoid the oxidation and splashing of tungsten-based materials, effectively repair at the edge damage, with high precision and a wide range of repairs.
[0005] Based on the above technical environment, the present invention provides an electron beam remelting repair method suitable for tungsten-based material components. Summary of the invention
[0006] In order to solve the technical problems mentioned in the above background technology, the present invention proposes the following technical solutions: An electron beam remelting repair method for tungsten-based material parts comprises the following steps: Step 1: Perform fine processing on the damaged parts to form a material filling cavity. According to the damage condition of the tungsten-based material parts, the damaged parts are compared with the reconstructed model of the original parts, and the minimum regular volume for complete damage removal is determined and measured. Pretreatment is performed to completely remove the matrix and inclusions that affect the connection state until the part to be repaired presents a regular geometric shape; Step 2: Fill the cavity with a matching tungsten block, and tightly fill the tungsten block that matches the size and shape of the cavity in the filling cavity formed after fine processing in an interference fit manner; Step 3: Remelting and repairing the tungsten block. Use a high-energy electron beam to scan the surface of the filled block at a high frequency along a specific scanning trajectory to make it evenly remelted, and the directional deposition and substrate are reliably metallurgically bonded to complete the damage repair. If the damage is deep, it can be remelted and filled multiple times until the processing size requirements are met; Step 4: Post-processing of the parts: machining the remelted surface to remove excess surface and ensure surface flatness and smoothness.
[0007] In the above technical solution, in step 2, the tungsten block is made of pure tungsten, and its shape includes one or more combinations of regular geometric bodies and non-powder irregular bodies to adapt to different filling cavities and ensure effective cooperation with the substrate.
[0008] In the above technical solution, in step 2, the regular geometric bodies are curved geometric bodies and planar geometric bodies, including cylinders, cones, prisms, pyramids, and cuboids.
[0009] In the above technical solution, in step 2, the non-powder irregular body includes a needle-like shape, a granular shape, and a rod-like shape.
[0010] In the above technical solution, in step 2, after a single filling, the maximum height of the block material as a whole along the construction direction is 0.3-2 mm.
[0011] In the above technical solution, in step 3, the electron beam power is 6~30kW, the scanning time is 3~10s, the scanning frequency is 100~1000Hz, the beam spot size is 0.5~1mm, and the scanning is performed in a pulsed or continuous manner; within 3s after the scanning is completed, the beam current is gradually reduced to 0mA to relieve thermal stress.
[0012] In the above technical solution, in step 3, the scanning track accurately covers the upper surface of the filled tungsten block.
[0013] In the above technical solution, in step 3, the scanning trajectory refers to the moving trajectory of the beam spot of the high-energy electron beam on the filled tungsten block, including traversal paths such as "I", "zigzag", "rectangle" and "circle".
[0014] In the above technical solution, in step 3, the cyclic surface scanning refers to the high-energy electron beam traversing and scanning the surface of the filled tungsten block, and continuously repeating the scanning trajectory within a predetermined time to uniformly heat and melt it.
[0015] In the above technical solution, in step 3, the whole process is under vacuum conditions, and the vacuum degree is better than 5×10 -2 Pa can greatly reduce the scattering of the electron beam, ensure high-energy convergence, and avoid high-temperature oxidation behavior of the material and oxide inclusions.
[0016] In the above technical solution, in step 3, water is passed for rapid cooling during the entire repair process.
[0017] In the above technical solution, in step 3, during multiple repairs, the quality of the deposited surface is ensured and foreign matter that affects the connection state is removed.
[0018] In the above technical solution, in step 3, during multiple repairs, the scanning tracks of adjacent repair layers along the construction direction are horizontally rotated and intersected to ensure complete melting and eliminate defects such as pores and undissolved particles. At the end of remelting, there is a processing allowance of not less than 0.3 mm.
[0019] Beneficial effects: 1. Compared with traditional repair, the repair method of the present invention repairs parts without introducing additional dissimilar materials (such as brazing filler metal and other repairing agents): remelting raw materials with the same composition as the matrix avoids the influence of heterogeneous interfaces and heterogeneous elements on the overall performance of the parts and the operation of the device, ensuring the complete consistency before and after the repair. The repair interface has a good metallurgical bond with the matrix, and has high bonding strength and fatigue resistance. In addition, the present invention has a wide range of repairs, and can adapt to various repair needs such as various damage types and complex curved surfaces through block matching; 2. Compared with the additive manufacturing repair using powder as raw material, the repair method of the present invention is block filling material. The raw material is simple and easy to obtain. There is no need for expensive and complicated process steps and passes such as powder making and powder spreading. The required cost and time are significantly reduced, the operation control is simple, and the repair efficiency is significantly improved. In addition, the block is easier to fix than the powder, and the single remelting thickness of mm level is significantly greater than the μm level of powder cladding. It is not easy to cause problems such as splashing and oxidation, and the repair effect of edge damage is significantly improved.
[0020] 3. High precision, local control of material thermal conditions to ensure uniform temperature rise, rapid remelting and solidification repair, single repair thickness up to mm level. In addition, the high-energy heat source action time does not exceed 13s, significantly improving efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 Schematic diagram of divertor edge crack repair technology (I).
[0022] Figure 2 Schematic diagram of divertor edge crack repair technology (II).
[0023] Figure 3 Schematic diagram of the ablation repair technology for the aircraft surface shielding layer (I).
[0024] Figure 4 Schematic diagram of the ablation repair technology for the aircraft surface shielding layer (Part 2).
[0025] Among them, 1-damage site, 2-regular cavity after pretreatment, 3-tungsten, 4-copper intermediate layer, 5-CuCrZr, 6-electron beam, 7-scanning track, 8-filling tungsten block. DETAILED DESCRIPTION
[0026] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and carefully in combination with preferred embodiments below, but the protection scope of the present invention is not limited to the following specific embodiments.
[0027] Embodiment 1: The electron beam remelting repair process for the edge cracked tungsten copper string is as follows (used for the shunt on EAST): like Figure 1 and Figure 2 As shown, 1 represents the damaged part, 2 represents the regular cavity after pretreatment, 3 represents tungsten, 4 represents the copper intermediate layer, 5 represents CuCrZr, 6 represents the electron beam, 7 represents the scanning track, and 8 represents the filling tungsten block.
[0028] (1) Fine processing: The multiple cracks on the edge of the tungsten copper string were completely removed by machining and made into regular rectangular grooves (3×6×1mm). The surface was polished step by step with sandpaper to Ra0.8, and then thoroughly cleaned with acetone and alcohol. After being air-dried with a hot air blower, it was immediately fixed in the electron gun vacuum chamber.
[0029] (2) Filling and adapting tungsten block: Prepare a 3.5×6×1.3mm rectangular block of rolled pure tungsten. The tolerance is slightly enlarged to fit the groove and ensure that the contact surfaces fit tightly (the maximum gap is less than 0.03mm).
[0030] (3) Tungsten block remelting repair: vacuum chamber is evacuated to better than 5×10 -2 Pa, using a full power 60kW electron gun, the parameters are adjusted to 150kV acceleration voltage, 60mA beam current, 9kW emission power, 0.7mm beam spot, "zigzag" track accurately covers the 3.5×6mm surface, and continuously scans the rectangular pure tungsten at a frequency of 500Hz along the "zigzag" track from the edge to make the pure tungsten uniformly melted and directionally deposited to fill the regular cavity, and the scanning time is 5s. Then keep the other parameters unchanged, reduce the electron beam current step by step at a speed of 20mA / s, and continue scanning for 3s until the beam current is 0mA. Cooling water is passed throughout the process to ensure a high cooling rate.
[0031] (4) Component post-processing: Remove excess 0.3 mm of the outer surface through machining to ensure that the repaired surface is flat and smooth, with a smooth transition with the original outer surface, and restore the geometric integrity.
[0032] After the repair, the present method forms a good metallurgical bond with the substrate, which can effectively avoid the problems of tungsten powder oxidation and splashing during powder cladding repair, and the difficulty of effective adhesion of the melt. After the block is remelted and repaired, the deposited layer has a high density, a smooth surface without cracks, and no oxidation or splashing during the repair process. The process is simple to operate, and the time and cost of raw material preparation and heat input are greatly shortened.
[0033] Embodiment 2: The electron beam remelting repair process for ablation of the aircraft surface shielding layer is as follows: like Figure 3 and Figure 4 As shown, 1 represents the damaged part, 2 represents the regular cavity after pretreatment, 3 represents tungsten, 6 represents the electron beam, 7 represents the scanning track, and 8 represents the filling tungsten block.
[0034] (1) Fine processing: For the melt-etching damage on the surface of the aircraft, the thermal ablation layer is completely removed by air blowing and machining, and the ablated part is machined into a regular rectangular groove (6×10×1.5mm). After being polished step by step with sandpaper to Ra0.4, the surface is thoroughly cleaned with acetone and alcohol, and immediately fixed in the electron gun vacuum chamber after air drying.
[0035] (2) Filling and adapting tungsten block: Prepare a 6×10×1.8mm rectangular block of rolled pure tungsten, slightly enlarge the size with tolerance to fit the groove, and ensure that each contact surface fits tightly with a maximum gap of 0.02mm.
[0036] (3) Tungsten block remelting repair: vacuum chamber is evacuated to better than 5×10 -2 Pa, using a full-power 60kW electron gun, an acceleration voltage of 150kV, a beam current of 200mA, an emission power of 30kW, and a beam spot size of 0.8mm, the "rectangular" track accurately covers the 6×10mm surface, and the rectangular pure tungsten is scanned along the "rectangular" track at a high frequency of 100Hz in a pulsed manner. The surface of the block is uniformly heated through a high-speed traversal cycle, so that the pure tungsten is uniformly melted and directionally deposited to fill the regular cavity. The scanning time lasts for 5s. Keeping the other parameters unchanged, the electron beam current is gradually reduced at a speed of 70mA / s, and the scanning continues for 3s until the beam current drops to 0mA. Cooling water is passed throughout the process to ensure a high cooling rate.
[0037] (4) Component post-processing: Machining removes 0.3 mm machining allowance on the outer surface to ensure that the repair surface is flat and smooth.
[0038] After repair by this implementation method, compared with the heterogeneous materials introduced by traditional welding repair, the same materials are connected to ensure the originality and consistency of the component materials. At the same time, the remelted tungsten block forms a good metallurgical bond with the matrix, and the bonding surface has excellent performance. It also has good flexibility, a large repair range, and high precision.
[0039] The present invention does not elaborate on some of the common technologies of those skilled in the art. The above-described embodiments are only descriptions of preferred implementations of the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementations described. Without departing from the design spirit of the present invention, various modifications and improvements made by ordinary technicians in this field to the technical solution of the present invention should fall within the scope of protection determined by the claims of the present invention.
Claims
1. An electron beam remelting repair method for tungsten-based material parts, characterized in that: The following steps are involved: Step 1: Perform fine processing on the damaged parts to form a material filling cavity. According to the damage condition of the tungsten-based material parts, the damaged parts are compared with the reconstructed model of the original parts, and the minimum regular volume for complete damage removal is determined and measured. Pretreatment is performed to completely remove the matrix and inclusions that affect the connection state until the part to be repaired presents a regular geometric shape; Step 2: Fill the cavity with a matching tungsten block, and tightly fill the tungsten block that matches the size and shape of the cavity in the filling cavity formed after fine processing in an interference fit manner; Step 3: Remelting and repairing the tungsten block. Use a high-energy electron beam to scan the surface of the filled block at a high frequency along a specific scanning trajectory to make it evenly remelted, and the directional deposition and substrate are reliably metallurgically bonded to complete the damage repair. If the damage is deep, it can be remelted and filled multiple times until the processing size requirements are met; Step 4: Post-processing of the parts: machining the remelted surface to remove excess surface and ensure surface flatness and smoothness.
2. The electron beam remelting repair method for tungsten-based material parts according to claim 1 is characterized in that: In step 2, the tungsten block is made of pure tungsten and has a shape that includes one or more combinations of regular geometric bodies and non-powder irregular bodies.
3. The electron beam remelting repair method for tungsten-based material parts according to claim 2 is characterized in that: The regular geometric bodies include cylinders, cones, prisms, pyramids, and cuboids.
4. The electron beam remelting repair method for tungsten-based material parts according to claim 2 is characterized in that: The non-powder irregular bodies include needle-shaped, granular-shaped, and rod-shaped.
5. The electron beam remelting repair method for tungsten-based material parts according to claim 1, characterized in that: In step 2, after a single filling, the maximum height of the entire tungsten block along the construction direction is 0.3-2 mm.
6. The electron beam remelting repair method for tungsten-based material parts according to claim 1, characterized in that: In step 3, the electron beam power is 6-30 kW, the scanning time is 3-10 s, the scanning frequency is 100-1000 Hz, the beam spot size is 0.5-1 mm, and the scanning is performed in a pulsed or continuous manner; within 3 s after the scanning is completed, the beam current is gradually reduced to 0 mA.
7. The electron beam remelting repair method for tungsten-based material parts according to claim 1, characterized in that: In step 3, the scanning trajectory includes traversal paths such as "I-shaped", "zigzag", "rectangular", and "circular".
8. The electron beam remelting repair method for tungsten-based material parts according to claim 1, characterized in that: In step 3, the vacuum degree is better than 5×10 -2 Pa.
9. The electron beam remelting repair method for tungsten-based material parts according to claim 1, characterized in that: In step 3, water cooling is performed during the repair process.