Alloy powder for repairing GH4169 extrusion cone die and composite repairing method of alloy powder

Abstract

The invention discloses alloy powder for repairing a GH4169 extrusion cone die and a composite repairing method of the alloy powder, and belongs to the technical field of extrusion die remanufacturing. The alloy powder is a Co-based high-temperature alloy and comprises the following components in percentage by mass: 45.0 to 55.0 percent of Co, 20.0 to 25.0 percent of Cr, 5.0 to 15.0 percent of Mo, 3.0 to 8.0 percent of W, 2.0 to 4.0 percent of Ni, 1.0 to 1.5 percent of Fe, 0.5 to 1.5 percent of Si and 0.2 to 0.5 percent of C. During repairing, the damaged area of the die is pretreated, the size is recovered through a GH4169 welding wire by adopting a CMT electric arc additive technology, and then the Co-based alloy functional layer is prepared on the surface of the damaged area through a laser cladding technology. According to the method, efficient and high-precision repair of the large-area deep damage die is achieved through combination of the special material and the additive repair-surface strengthening composite technology, the obtained functional layer is compact in structure, high in hardness and excellent in abrasion resistance, the secondary service life of the die is remarkably prolonged, and the method is suitable for repair and performance improvement of the copper alloy extrusion cone die.

Description

Technical Field

[0001] This invention relates to the field of extrusion die repair technology, and more specifically, to a repair material and repair method for GH4169 extrusion cone die used in copper alloy extrusion production. Background Technology

[0002] In the extrusion production of copper alloy tubes, the extrusion die is a key component for achieving ingot forming and controlling product dimensions and surface quality. Its performance directly determines production efficiency and product quality. Dies are typically made of high-strength nickel-based superalloys such as GH4169 to withstand extreme working environments: high temperatures (typically 800-1000℃), high pressures (extrusion stresses can reach 1000-1500MPa), and intense friction and adhesion with the high-temperature copper alloy billet. During long-term, cyclical service, critical areas such as the inlet cone angle and sizing zone of the extrusion die are prone to severe wear, plastic deformation, surface cracking, and even overall collapse—a complex failure mode. This damage not only leads to dimensional deviations in the extruded tubes, scratches, or copper plating on the surface, but also causes frequent downtime for replacement, significantly increasing production costs and resulting in substantial resource waste due to die scrap.

[0003] To extend mold life and reduce production costs, repairing and remanufacturing failed molds has become an important development direction in the industry. Currently, mold repair technologies mainly include traditional arc welding, electroplating, thermal spraying, electrical discharge deposition, and laser cladding. However, for the large-area, deep damage unique to the GH4169 extrusion cone die (such as collapses and cracks reaching depths of 15-20mm), each of these individual technologies has significant limitations: traditional welding has high heat input, easily leading to overheating, deformation, or even cracking of the substrate; thermal spraying coatings rely primarily on mechanical bonding, making it difficult to withstand the high shear forces during extrusion; while conventional laser cladding can achieve excellent metallurgical bonding layers, its deposition efficiency is low, resulting in insufficient efficiency and high costs when repairing large-area, deep defects. More importantly, most existing repair materials are general-purpose alloys, lacking specialized materials designed for the extreme conditions of copper alloy extrusion cone dies (high temperature, high pressure, strong friction and copper adhesion). This makes it difficult for the repair layer to meet the performance requirements of "restoring to new condition" in terms of hardness, wear resistance, high temperature stability and compatibility with the GH4169 substrate.

[0004] Therefore, the core challenge in the current technological field lies in developing a composite repair process capable of efficiently repairing large-area, deep damage to GH4169 extrusion cone dies, and matching it with a specialized repair material possessing excellent high-temperature wear resistance and deformation resistance. This process must combine high-efficiency dimensional recovery with precision surface strengthening with low heat input. The material must achieve a high-strength metallurgical bond with the GH4169 matrix, and its overall performance must surpass that of the matrix material. Solving this problem is of great significance for improving the mold management level of my country's copper processing industry, achieving cost reduction and efficiency improvement, and promoting green manufacturing. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies in repairing large-area deep damage to GH4169 extrusion cone dies, such as low efficiency, insufficient bonding strength, and difficulty in meeting the performance requirements of the repair layer under extreme working conditions. This invention provides a dedicated repair alloy powder and a highly efficient composite repair method adapted to it. This method aims to achieve high-precision and high-efficiency restoration of die dimensions and a significant improvement in surface properties, ultimately enabling the repaired extrusion cone die to reach or even exceed the service performance of a new die, extending its service life and reducing production costs.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: Firstly, this invention provides a Co-based high-temperature alloy powder specifically for repairing GH4169 extrusion cone dies. The components and their mass percentages of the alloy powder are as follows: Co 45.0–55.0%, Cr 20.0–25.0%, Mo 5.0–15.0%, W 3.0–8.0%, Ni 2.0–4.0%, Fe 1.0–1.5%, Si 0.5–1.5%, C 0.2–0.5%, with the balance being unavoidable impurities. This powder is prepared using a high-energy ball milling method to ensure uniform composition. This compositional design ensures high-temperature red hardness and thermal stability through the Co matrix, achieves solid solution strengthening, carbide formation, and high-temperature oxidation protection through the composite addition of Cr, Mo, and W elements, and generates a hard reinforcing phase in situ by controlling the Si and C content, thereby endowing the final repair coating with excellent high-temperature wear resistance, resistance to plastic deformation, and good metallurgical compatibility with the GH4169 substrate.

[0007] Secondly, this invention provides a composite repair method for GH4169 extrusion cone dies. This method combines efficient dimensional recovery technology with precise surface strengthening technology, and specifically includes the following steps: S1. Pre-treat the area to be repaired of the GH4169 extrusion cone die to remove the surface defect layer; S2. Using CMT arc additive manufacturing technology, with GH4169 welding wire as the material, additive manufacturing is performed in the pre-treated area to restore the dimensions; S3. After additive manufacturing, the area is machined to remove excess material, and then subjected to solution treatment and aging heat treatment; S4. Using laser cladding technology, the Co-based alloy powder is clad onto the surface of the machined area to form a surface functional layer; S5: After cladding, the functional layer is finely processed to the final design dimensions to ensure that the functional layer retains a design thickness of 1.0~1.5mm, and the quality of the repair layer is verified by non-destructive testing methods.

[0008] In step S1, the pretreatment includes turning the inlet cone angle and sizing zone area to a depth of 15-20 mm.

[0009] In step S2, the process parameters for CMT arc additive manufacturing include: wire feed speed 5.0~6.5 m / min, welding speed 300~600 mm / min, argon as the protective gas, gas pressure 0.1~0.3MPa, and additive manufacturing of the extrusion die turning area using a circular repair trajectory; the mass percentage of each component of the GH4169 welding wire is: C≤0.05%, Si≤0.5%, Mn≤0.32%, Cr 17.00~21.0%, Co≤1.0%, Mo 2.8~3.3%, Ti 0.65~1.15%, Al 0.2~0.8%, Nb 4.75~5.5%, Ni 50~55%, and Fe balance.

[0010] Step S3 includes solution treatment and aging heat treatment of the machined extrusion cone die. The solution treatment includes holding at 1150℃±10℃ and then air cooling, and a second solution treatment at 980℃±10℃ followed by air cooling. The aging treatment includes holding at 720℃±10℃, then cooling in the furnace to 620℃±10℃ and holding at that temperature, and finally air cooling.

[0011] In step S4, the process parameters for laser cladding include: laser power of 2000~2500W, scanning speed of 300~500mm / min, spot diameter of 3~5mm, powder feeding method of coaxial powder feeding, powder feeding rate of 2.0~2.5r / min, argon as protective gas, gas pressure of 0.1~0.3MPa, and the laser scanning trajectory is a circular trajectory, with cladding from the inner circle to the outer circle, and an overlap rate of 30~50%.

[0012] Thirdly, the present invention also provides the application of the above-mentioned Co-based alloy powder and the above-mentioned composite repair method in the field of repair and remanufacturing of copper alloy extrusion dies (especially GH4169 material dies).

[0013] Compared with existing technologies, the beneficial effects of this invention are mainly reflected in the following: It employs a composite repair strategy combining "CMT arc additive manufacturing for dimensional restoration" and "laser cladding for functional enhancement," and uses specialized Co-based alloy powder to synergistically solve the engineering challenge of repairing large-area, deep damage to GH4169 extrusion cone dies. This solution achieves near-net-shape dimensional restoration of the damaged die with high efficiency and low thermal deformation through CMT technology; furthermore, by using laser cladding with specialized powder, a functional layer with high hardness, excellent wear resistance, and strong resistance to high-temperature softening is formed on the repair surface, significantly surpassing the performance of the GH4169 substrate. Ultimately, the repaired die not only reliably restores dimensional accuracy and substrate performance, but its key working surfaces also achieve wear resistance and temperature resistance exceeding that of new products, achieving true "repair as new," significantly extending die life, and demonstrating outstanding industrial applicability and economic benefits. Attached Figure Description

[0014] Figure 1 Microstructure image of the repair layer prepared in Example 1; Figure 2 The cross-sectional hardness distribution diagram of the repair layer prepared in Example 1 is shown. Detailed Implementation

[0015] This invention provides an alloy powder for repairing GH4169 extrusion cone dies and a repair method thereof, including the repair alloy powder and the repair method; The base material of the extrusion cone die is GH4169 with a hardness of HRC45~50. Its excellent high-temperature mechanical properties are used to manufacture the extrusion cone die. After repeated use, severe metal flow occurred at the cone tip, resulting in defects such as collapse, slippage, and cracking. The defects covered a wide area and the cracks were deep, which could not meet the actual use requirements and required repair.

[0016] The first repair material used in CMT arc additive manufacturing is GH4169 welding wire, which is homogeneous with the mold substrate. The mass percentage composition of each component is as follows: C≤0.05%, Si≤0.5%, Mn≤0.32%, Cr 17.00~21.0%, Co≤1.0%, Mo 2.8~3.3%, Ti 0.65~1.15%, Al 0.2~0.8%, Nb 4.75~5.5%, Ni 50~55%, and Fe balance.

[0017] The welding wire is available in one of three diameters: 0.8mm, 1.2mm, and 1.6mm.

[0018] The second repair material forming the surface functional layer is a Co-based alloy powder, with the following mass percentage composition: Co 45.0~55.0%, Cr 20.0~25.0%, Mo 5.0~15.0%, W 3.0~8.0%, Ni 2.0~4.0%, Fe 1.0~1.5%, Si 0.5~1.5%, and C 0.2~0.5%.

[0019] Co-based alloys exhibit superior high-temperature mechanical properties, high-temperature red hardness, thermal stability, and wear resistance compared to Fe-based and Ni-based alloys. Furthermore, Co-based alloys demonstrate excellent compatibility with GH4169, which enhances interfacial bonding strength. Additionally, Co and Ni can form a stable solid solution, improving the interfacial toughness of the repair layer. Therefore, a Co-based alloy with good compatibility with GH4169 was chosen as the repair material for the surface functional layer.

[0020] Adding chromium (Cr) improves the high-temperature oxidation resistance of the repair layer and acts as a solid solution strengthener and a second-phase strengthener, thereby enhancing the wear resistance of the repair layer. Under high-temperature conditions, Cr forms a dense Cr₂O₃ passivation film, preventing oxygen from diffusing into the repair layer. Simultaneously, Cr and carbon (C) form hard carbides, increasing the hardness and wear resistance of the repair layer. The Cr content is 20.0%–25.0%, specifically 20%, 21%, 22%, 23%, 24%, and 25%. Variations in Cr content can adapt to different repair needs of extrusion cone dies, improving the applicability of the repair material.

[0021] Adding Mo enhances the repair layer's resistance to cracking, thermal strength, high-temperature friction reduction, oxidation resistance, and resistance to plastic deformation. Under high-temperature conditions, Mo forms oxides and bimetallic composite salts, including MoO3 and MoO2, which prevent oxygen from penetrating into the repair layer. Furthermore, these oxides and bimetallic composite salts form a dense enamel layer under extrusion pressure, acting as an excellent high-temperature lubricant and further improving the friction and wear performance of the repair layer. The Mo content ranges from 5.0% to 15.0%, specifically 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, and 15%. By adjusting the Mo content in the Co-based alloy powder, the repair requirements of extrusion cone dies under different service conditions can be met.

[0022] Adding titanium dioxide (W) can improve the hardness, heat resistance, high-temperature strength, and wear resistance of the repair layer. Due to its large atomic size, W's solid solution can induce lattice distortion, thereby increasing hardness and strength and extending the service life of the repair layer. The solid solution of W, Mo, and Cr can hinder dislocation movement. W can also combine with carbon to form carbide particles, which can enhance the wear resistance of the repair layer as a second phase. Furthermore, the hard particles such as tungsten carbide formed by W accumulate at grain boundaries, inhibiting grain growth and refining the grain size. The W content is 3.0%–8.0%, specifically 3.0%, 4.0%, 5.0%, 6.0%, 7.0%, and 8.0%.

[0023] Adding small amounts of Ni and Fe elements can form a continuous solid solution with Co, which strengthens the matrix and improves the strength, toughness, and fatigue resistance of the repair layer. To adapt to different service conditions of extrusion cone dies, the Fe content is 1.0~1.5%, specifically 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, and 1.5%, and the Ni content is 2.0~4.0%, specifically 2.0%, 2.5%, 3.0%, 3.5%, and 4.0%.

[0024] Under the influence of a high-energy laser beam, the addition of Si and C elements can react in situ with elements such as Mo, Cr, and W in the alloy to form silicides and carbides, thus acting as particle reinforcement and improving the hardness and wear resistance of the repair layer. The addition of Si can enhance the oxidation resistance and mechanical properties of the repair layer. Furthermore, the addition of Si acts as a deoxidizer and slag-forming agent, improving the metallurgical quality and density of the repair layer. To adapt to various service conditions of the extrusion die and to control the hardness of the repair layer, the Si content is 0.5–1.5%, specifically 0.5%, 1.0%, and 1.5%; the C content is 0.2–0.5%, specifically 0.2%, 0.3%, 0.4%, and 0.5%.

[0025] The particle size of each elemental powder constituting the Co-based alloy powder is 50~120μm, and the purity is greater than or equal to 99.5%.

[0026] The preparation method of Co-based alloy powder is high-energy ball milling. The ball milling speed is 300~600 r / min, specifically 300 r / min, 400 r / min, 500 r / min, or 600 r / min. The ball milling time is 5~10 h, specifically 5 h, 6 h, 7 h, 8 h, 9 h, or 10 h. The ball-to-powder ratio is 8:1~10:1, specifically 8:1, 9:1, or 10:1. The ball milling is carried out under the protection of an inert gas atmosphere, preferably argon. After ball milling, the powder is sieved and dried. The drying temperature is 80~100℃, specifically 80℃, 85℃, 90℃, 95℃, or 100℃; the drying time is 1~2 h, specifically 1 h, 1.5 h, or 2 h.

[0027] This invention also provides a method for repairing GH4169 extrusion cone dies, using the aforementioned repair material on the surface of the extrusion cone die to be repaired, comprising the following steps: The surface of the extrusion die to be repaired is pre-treated. Using the end face of the extrusion die as a reference, the area around the inlet cone angle and the sizing zone is machined to remove surface cracks, deformed layers, and collapsed areas. The machining depth is 15-20 mm, aiming to remove all cracks and deformed layers. After machining, anhydrous ethanol, cyclohexane, or acetone are used to clean the oil stains and impurities in the machined area.

[0028] Additive manufacturing of turning dies was performed using CMT (Continuous Metal-Injection) arc additive manufacturing technology, with GH4169 welding wire as the first repair material. The CMT arc additive manufacturing process parameters were: CrNi199 data package, CMT mode, wire feed speed of 5.0~6.5 m / min (specifically 5.0 m / min, 5.5 m / min, 6.0 m / min, 6.5 m / min), welding speed of 300~600 mm / min (specifically 300 mm / min, 400 mm / min, 500 mm / min, 600 mm / min), argon as the shielding gas, and pressure of 0.1~0.3 MPa (specifically 0.1 MPa, 0.2 MPa, 0.3 MPa). A circular repair trajectory was used to additively manufacture the turning area of ​​the extrusion cone die to meet dimensional requirements.

[0029] The additively manufactured extrusion cone die is machined to meet the design dimensional requirements. Simultaneously, based on the design dimensions, the small end face of the extrusion cone die is reduced by 1.0~1.5mm to prepare a surface functional layer.

[0030] The machined extrusion cone die underwent solution treatment and aging to meet the hardness requirements of the GH4169 repair layer, which is comparable to that of the die substrate. Solution treatment regime: temperature 1150 ℃±10 ℃, holding time 1 h, air cooling to room temperature; followed by a second solution treatment at 980℃±10 ℃, holding time 1 h, air cooling to room temperature. After solution treatment, aging treatment was performed at 720 ℃±10 ℃, holding time 8 h, followed by furnace cooling to 620℃±10 ℃ for 2 h, holding time 8 h, and then air cooling to room temperature.

[0031] Laser cladding technology was used to clad a second repair material, Co-based alloy, in the GH4169 repair area to form a surface functional layer. The laser cladding process parameters include: laser power of 2000~2500W, specifically 2000W, 2100W, 2200W, 2300W, 2400W, or 2500W; scanning speed of 300~500mm / min, specifically 300 mm / min, 400 mm / min, or 500 mm / min; spot diameter of 3~5mm; coaxial powder feeding method; powder feeding rate of 2.0~2.5r / min, specifically 2.0r / min, 2.1r / min, 2.2r / min, 2.3r / min, 2.4r / min, or 2.5r / min; argon as the protective gas; pressure of 0.1~0.3MPa; and a circular laser scanning trajectory, with cladding from the inner circle to the outer circle, and an overlap rate of 30~50%, specifically 30%, 40%, or 50%.

[0032] The extrusion die for the cladding surface functional layer is machined to meet the design dimensional requirements, and the thickness of the surface functional layer is ensured to be 1.0~1.5mm after machining. The machined extrusion die is subjected to dye penetrant testing to detect defects. The repair layer after machining is then tested using DPT-5 penetrant testing agent, including spraying, wiping, and spraying developer. Defects may include cracks and porosity. DPT-5 penetrant testing shows that the repair layer formed by the repair method of this invention has high reliability, with a pass rate exceeding 99%.

[0033] It should be noted that although the steps of the GH4169 extrusion cone die repair method of the present invention are described in a specific order in the accompanying drawings, this does not mean that these steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps, etc.

[0034] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0035] Example 1 The repair material is composed of powder with the following mass percentages: Co balance, Cr 25.0%, Mo 10.0%, W 8.0%, Ni 4.0%, Fe 1.5%, Si 1.0%, and C 0.3%. The raw materials with a particle size of 50~120μm and a purity of ≥99.5% are proportioned according to the above alloy ratio.

[0036] For the preparation of the repair material, the mixed powder was ball-milled using a high-energy ball mill. The ball milling parameters were as follows: tungsten carbide grinding balls were used, the ball-to-powder ratio was 8:1, the rotation speed was 300 r / min, and ball milling was carried out for 5 hours under an argon atmosphere to ensure thorough mixing of the components and form the repair material. The ball-milled repair material was then sieved and dried in an 80℃ drying oven for 1 hour to obtain the GH4169 extrusion cone die repair material.

[0037] The damaged mold is pre-treated by turning the area around the entrance cone angle and the sizing zone, using the end face of the extrusion cone as a reference, to remove surface cracks, deformation layers and collapsed areas. The turning depth is 20mm. After turning, the oil stains and impurities in the turning area are cleaned with anhydrous ethanol.

[0038] The machined mold was additively manufactured using CMT arc additive manufacturing technology. The additive manufacturing material was GH4169 welding wire, which was the first repair material. The percentage content of each component was as follows: C 0.02%, Si 0.32%, Mn 0.24%, Cr 18.75%, Co 0.31%, Mo 3.13%, Ti 0.75%, Al 0.34%, Nb 5.13%, Ni 54.83%, Fe balance, and the welding wire diameter was 1.2mm.

[0039] CMT arc additive manufacturing process parameters: CrNi19 9 data package, CMT mode, wire feed speed 6.0m / min, welding speed 500mm / min, argon as shielding gas, gas pressure 0.2MPa, and additive manufacturing of the extrusion cone die turning area using a circular repair trajectory.

[0040] The additive manufacturing area of ​​the mold is machined by turning to meet the dimensional requirements of the extrusion cone die. At the same time, based on the design dimensions, the small end face of the extrusion cone die is reduced by 1.2mm.

[0041] The machined extrusion cone die underwent solution treatment and aging. Solution treatment regime: temperature 1150℃±10℃, holding time 1 h, air cooling to room temperature; followed by a second solution treatment at 980℃±10℃, holding time 1 h, air cooling to room temperature. After solution treatment, aging treatment was performed at 720℃±10℃, holding time 8 h, followed by furnace cooling to 620℃±10℃ for 2 h, holding time 8 h, and then air cooling to room temperature.

[0042] Laser cladding technology was used to clad a second repair material, Co-based alloy powder, onto the GH4169 repair area to form a surface functional layer. The laser cladding process parameters included: laser power of 2200W, scanning speed of 500mm / min, spot diameter of 4mm, coaxial powder feeding method at a powder feeding rate of 2.2r / min, argon as the protective gas at a pressure of 0.2MPa, and a circular laser scanning trajectory with cladding from the inner to the outer ring, resulting in an overlap rate of 40%.

[0043] The extrusion cone die after cladding is machined to meet the design dimensional requirements, and the surface functional layer thickness is ensured to be 1.2mm after machining; The extrusion die after machining was subjected to dye penetrant testing, and no obvious defects were found in the repaired area.

[0044] Figure 1 The image shows the cross-sectional microstructure of the repair layer in Example 1. This was obtained by cutting, grinding, polishing, and metallographic etching (using aqua regia as the etchant), followed by microscopic analysis of the repair layer's microstructure. As can be seen from the image, the repair layer obtained in Example 1 has a uniform structure and fine microstructure, with good metallurgical bonding between the Co-based functional layer and GH4169. No obvious defects such as pores, cracks, or inclusions were observed in the Co-based surface functional layer, indicating good repair layer quality.

[0045] It should be noted that the microstructure of the repair layer cross section formed by applying the above-mentioned repair materials is similar, and each embodiment will not be described in detail here.

[0046] Figure 2 The image shows the Vickers hardness distribution of the repair layer in Example 1. The hardness distribution of the repair layer was tested using a Vickers hardness tester with a load of 5000 gf and a holding time of 10 s. Hardness was measured every 0.1 mm from the surface of the repair layer towards the GH4169 layer. The average hardness of the Co-based functional layer was measured to be 554.8 HV5, and the average hardness of the GH4169 layer was 460.2 HV5.

[0047] High-temperature friction and wear test: A Co-based functional layer was prepared on the surface of GH4169 according to the above process. The sample was processed into a friction specimen with dimensions of 31mm × 10mm × 4mm. After polishing, the specimen surface was cleaned with anhydrous ethanol. The friction and wear properties of the Co-based coating and the GH4169 substrate were tested using an RTECMFT-3000 high-temperature friction testing machine. Test conditions: The test temperature was 800℃, the corresponding friction pair was a 6.35mm diameter Si3N4 ball (hardness: 1700±20 HV), the load was 20N, the stroke was 5mm, the frequency was 5Hz, and the test time was 60min. To ensure the authenticity and repeatability of the test data, three tests were conducted under the same conditions, and the average value was taken. The test results show that the coefficient of friction of GH4169 is 0.67, and the wear rate is 20.34 × 10⁻⁶. -6 mm 3 / (Nm), the coefficient of friction of the Co-based coating is 0.43, and the wear rate is 5.46×10. -6 mm 3 The coefficient of friction and wear rate of the Co-based coating are both lower than those of the GH4169 substrate.

[0048] Example 1-1 With the preparation of repair materials, pretreatment of the extrusion die surface to be repaired, CMT additive manufacturing process parameters, solution aging treatment regime, laser cladding process parameters, turning of the repaired extrusion die, and dye penetrant testing of the repair layer all being the same as in Example 1, the Co-based repair material is composed of powder with the following mass percentages: Co balance, Cr 25.0%, Mo 10.0%, W 8.0%, Ni 4.0%, Fe 1.5%, Si 1.5%, and C 0.5%.

[0049] Testing revealed that the repaired Co-based functional layer had an average hardness of 585.4 HV5, a coefficient of friction of 0.40, and a wear rate of 3.46 × 10⁻⁶. -6 mm 3 / (Nm), the coefficient of friction and wear rate are both less than those of GH4169 substrate.

[0050] Examples 1-2 With the preparation of repair materials, pretreatment of the extrusion die surface to be repaired, CMT additive manufacturing process parameters, solution aging treatment regime, laser cladding process parameters, turning of the repaired extrusion die, and dye penetrant testing of the repair layer all being the same as in Example 1, the Co-based repair material is composed of powder with the following mass percentages: Co balance, Cr 25.0%, Mo 10.0%, W 8.0%, Ni 4.0%, Fe 1.5%, Si 0.5%, and C 0.2%.

[0051] The test results showed that the average hardness of the repaired Co-based functional layer was 536.2HV5, the coefficient of friction was 0.45, and the wear rate was 6.76×10-6 mm3 / (Nm). Both the coefficient of friction and the wear rate were lower than those of the GH4169 substrate.

[0052] By comparing Examples 1, 1-1, and 1-2, it can be seen that with the increase of Si and C content, the Vickers hardness of the Co-based functional layer tends to increase, while the coefficient of friction and wear rate tend to decrease. Therefore, based on the actual service conditions of the extrusion die, Co-based repair layers with different hardness can be obtained by adjusting the content of Si and C elements to meet different repair needs.

[0053] Examples 1-3 With the preparation of repair materials, pretreatment of the extrusion die surface to be repaired, CMT additive manufacturing process parameters, solution aging treatment regime, laser cladding process parameters, turning of the repaired extrusion die, and dye penetrant testing of the repair layer all being the same as in Example 1, the Co-based repair material is composed of powder with the following mass percentages: Co balance, Cr 25.0%, Mo 5.0%, W 8.0%, Ni 4.0%, Fe 1.5%, Si 1.0%, and C 0.3%.

[0054] The tests showed that the average hardness of the repaired Co-based functional layer was 533.8 HV5, the coefficient of friction was 0.52, and the wear rate was 15.35 × 10⁻⁶. -6 mm 3 / (Nm), the coefficient of friction and wear rate are both less than those of GH4169 substrate.

[0055] Comparing Examples 1-3 with Example 1, the reduced Mo content in Examples 1-3 resulted in a decrease in the Vickers hardness of the repair layer, while increasing the high-temperature friction coefficient and wear rate. Therefore, appropriately increasing the Mo content in the repair material within a certain range can improve the hardness of the repair layer and reduce its friction coefficient and wear rate.

[0056] Examples 1-4 With the preparation of repair materials, pretreatment of the extrusion die surface to be repaired, CMT additive manufacturing process parameters, solution aging treatment regime, laser cladding process parameters, turning of the repaired extrusion die, and dye penetrant testing of the repair layer all being the same as in Example 1, the Co-based repair material is composed of powder with the following mass percentages: Co balance, Cr 20.0%, Mo 10.0%, W 8.0%, Ni 4.0%, Fe 1.5%, Si 1.0%, and C 0.3%.

[0057] The tests showed that the average hardness of the repaired Co-based functional layer was 518.8 HV5, the coefficient of friction was 0.48, and the wear rate was 8.35 × 10⁻⁶. -6 mm 3 / (Nm), the coefficient of friction and wear rate are both less than those of GH4169 substrate.

[0058] Comparing Examples 1-4 with Example 1, the reduced Cr content in Examples 1-4 resulted in a decrease in the Vickers hardness of the repair layer and an increase in the high-temperature friction coefficient and wear rate. Therefore, appropriately increasing the Cr content in the repair material within a certain range can improve the hardness of the repair layer and reduce its friction coefficient and wear rate.

[0059] Examples 1-5 With the preparation of repair materials, pretreatment of the extrusion die surface to be repaired, CMT additive manufacturing process parameters, solution aging treatment regime, laser cladding process parameters, turning of the repaired extrusion die, and dye penetrant testing of the repair layer all being the same as in Example 1, the Co-based repair material is composed of powder with the following mass percentages: Co balance, Cr 25.0%, Mo 10.0%, W 4.0%, Ni 4.0%, Fe 1.5%, Si 1.0%, and C 0.3%.

[0060] The tests showed that the average hardness of the repaired Co-based functional layer was 509.6 HV5, the coefficient of friction was 0.50, and the wear rate was 11.85 × 10⁻⁶. -6 mm 3 / (Nm), the coefficient of friction and wear rate are both less than those of GH4169 substrate.

[0061] Comparing Examples 1-5 with Example 1, the reduced W content in Examples 1-5 resulted in a decrease in the Vickers hardness of the repair layer and an increase in the high-temperature friction coefficient and wear rate. Therefore, appropriately increasing the W content in the repair material within a certain range can improve the hardness of the repair layer and reduce its friction coefficient and wear rate.

[0062] Example 2 The repair material is composed of powder with the following mass percentages: Co 48.0%, Cr 20.0%, Mo 7.7%, W 6.0%, Ni 3.0%, Fe 1.3%, Si 1.0%, and C 0.3%. The raw materials with a particle size of 50~120μm and a purity of ≥99.5% are proportioned according to the above alloy ratio.

[0063] Preparation of repair material: The mixed powder was ball-milled using a high-energy ball mill. The milling parameters were as follows: tungsten carbide grinding balls, a ball-to-powder ratio of 8:1, a rotation speed of 300 r / min, and ball milling for 5 hours under an argon atmosphere to ensure thorough mixing of the components and form the repair material. The ball-milled repair material was then sieved and dried in an 80℃ drying oven for 1 hour to obtain GH4169 extrusion cone die repair material.

[0064] The damaged mold is pre-treated by turning the area around the entrance cone angle and the sizing zone, using the end face of the extrusion cone as a reference, to remove surface cracks, deformation layers and collapsed areas. The turning depth is 20mm. After turning, the oil stains and impurities in the turning area are cleaned with anhydrous ethanol.

[0065] The machined mold was additively manufactured using CMT arc additive manufacturing technology. The additive manufacturing material was GH4169 welding wire, which was the first repair material. The percentage content of each component was as follows: C 0.02%, Si 0.32%, Mn 0.24%, Cr 18.75%, Co 0.31%, Mo 3.13%, Ti 0.75%, Al 0.34%, Nb 5.13%, Ni 54.83%, Fe balance, and the welding wire diameter was 1.2mm.

[0066] CMT arc additive manufacturing process parameters: CrNi19 9 data package, CMT mode, wire feed speed 6.0m / min, welding speed 500mm / min, argon as shielding gas, gas pressure 0.2MPa, and additive manufacturing of the extrusion cone die turning area using a circular repair trajectory.

[0067] The additive manufacturing area of ​​the die is machined by turning to meet the dimensional requirements of the extrusion cone die. At the same time, based on the design dimensions, the small end face of the extrusion cone die is reduced by 1.0 mm.

[0068] The machined extrusion cone die underwent solution treatment and aging. Solution treatment regime: temperature 1150℃±10℃, holding time 1 h, air cooling to room temperature; followed by a second solution treatment at 980℃±10℃, holding time 1 h, air cooling to room temperature. After solution treatment, aging treatment was performed at 720℃±10℃, holding time 8 h, followed by furnace cooling to 620℃±10℃ for 2 h, holding time 8 h, and then air cooling to room temperature.

[0069] Laser cladding technology was used to clad a second repair material, Co-based alloy powder, onto the GH4169 repair area to form a surface functional layer. The laser cladding process parameters included: laser power of 2200W, scanning speed of 500mm / min, spot diameter of 4mm, coaxial powder feeding method at a powder feeding rate of 2.2r / min, argon as the protective gas at a pressure of 0.2MPa, and a circular laser scanning trajectory with cladding from the inner to the outer ring, resulting in an overlap rate of 40%.

[0070] The extrusion cone die after cladding is machined to meet the design dimensional requirements, and the surface functional layer thickness is ensured to be 1.0 mm after machining; The extrusion die after machining was subjected to dye penetrant testing, and no obvious defects were found in the repaired area.

[0071] The average hardness of the GH4169 layer was found to be 456.3 HV5.

[0072] Example 2-1 With the same material composition, preparation process, pretreatment of the extrusion die surface to be repaired, solution aging treatment regime, laser cladding process parameters, turning of the extrusion die after repair, and dye penetrant testing of the repair layer as in Example 2, the CMT arc additive manufacturing process parameters are as follows: CrNi19 9 data package, CMT mode, wire feed speed of 6.0 m / min, welding speed of 300 mm / min, argon as the protective gas, gas pressure of 0.2 MPa, and additive manufacturing of the turning area of ​​the extrusion die using a circular repair trajectory.

[0073] The average hardness of the GH4169 layer was found to be 454.8 HV5.

[0074] Example 2-2 With the same material composition, preparation process, pretreatment of the extrusion die surface to be repaired, solution aging treatment regime, laser cladding process parameters, turning of the extrusion die after repair, and dye penetrant testing of the repair layer as in Example 2, the CMT arc additive manufacturing process parameters are as follows: CrNi19 9 data package, CMT mode, wire feed speed of 6.0 m / min, welding speed of 600 mm / min, argon as the protective gas, gas pressure of 0.2 MPa, and additive manufacturing of the turning area of ​​the extrusion die using a circular repair trajectory.

[0075] The average hardness of the GH4169 layer was found to be 458.2HV5.

[0076] By comparing Examples 2, 2-1, and 2-2, it can be seen that the average hardness of the GH4169 layer remains basically unchanged as the CMT welding speed increases. Therefore, while ensuring the forming quality of the GH4169 additive manufacturing layer, appropriately increasing the welding speed can improve the repair efficiency of the extrusion die.

[0077] Example 3 In the case where the composition of the repair material, the preparation process, the pretreatment of the surface to be repaired of the extrusion die, the CMT additive manufacturing process parameters, the laser cladding process parameters, the turning of the extrusion die after repair, and the dye penetrant testing of the repair layer are all the same as in Example 2, but the extrusion die is not subjected to solution treatment and aging treatment after CMT additive manufacturing, and the Co-based functional layer is directly laser clad.

[0078] The average hardness of the GH4169 layer was found to be 263.6 HV5.

[0079] The comparison shows that without solution treatment and aging after CMT additive manufacturing, the average hardness of the GH4169 additive layer is only 263.6HV5. Therefore, in order to maintain the hardness of the GH4169 additive layer comparable to that of the die substrate, solution treatment and aging are necessary for the extrusion die.

[0080] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. An alloy powder for repairing a GH4169 extrusion cone die, characterized by, The alloy powder is a Co-based high-temperature alloy, and the mass percentage of each component is: Co 45.0-55.0%, Cr 20.0-25.0%, Mo 5.0-15.0%, W 3.0-8.0%, Ni 2.0-4.0%, Fe 1.0-1.5%, Si 0.5-1.5%, C 0.2-0.5%, and the balance is inevitable impurities.

2. The alloy powder of claim 1, wherein, The alloy powder is prepared by a high-energy ball milling method, the ball milling is carried out under inert gas protection, the ball milling speed is 300-600 r / min, the ball milling time is 5-10 h, the milling ball is tungsten carbide ball, and the ball-to-material ratio is 8:1-10:

1.

3. A method of repairing a GH4169 extrusion cone die, comprising: Comprising the following steps: S1. Pretreating the to-be-repaired area of the GH4169 extrusion cone die, removing the surface defect layer; S2. Using CMT electric arc additive manufacturing technology, using GH4169 welding wire as the material, additive manufacturing in the pretreated area to restore the size; S3. Machining the area after additive manufacturing to remove the excess amount, and performing solid solution and aging heat treatment; S4. Using laser cladding technology, cladding the Co-based alloy powder as claimed in claim 1 on the surface of the area after machining to form a surface functional layer.

4. The composite repair method of claim 3, wherein, In step S1, the pretreatment includes turning the inlet cone angle and the sizing zone, and the turning depth is 15-20 mm.

5. The composite repair method of claim 3, wherein, In step S2, the process parameters of the CMT electric arc additive manufacturing include: wire feeding speed 5.0-6.5 m / min, welding speed 300-600 mm / min, argon as the protective gas, gas pressure 0.1-0.3 MPa, and using a circular repair track to additively manufacture the turned area of the extrusion cone die.

6. The composite repair method of claim 3, wherein, Step S3 includes solid solution and aging heat treatment of the extrusion cone die after machining, the solid solution treatment includes air cooling after heat preservation at 1150℃±10℃, and air cooling after secondary solid solution at 980℃±10℃; the aging treatment includes air cooling after heat preservation at 720℃±10℃, furnace cooling to 620℃±10℃ and heat preservation, and finally air cooling.

7. The composite repair method of claim 3, wherein, In step S4, the process parameters of the laser cladding include: laser power 2000-2500 W, scanning speed 300-500 mm / min; powder feeding method is coaxial powder feeding method, powder feeding rate is 2.0-2.5 r / min, argon as the protective gas, and gas pressure 0.1-0.3 MPa.

8. The composite repair method according to any one of claims 3 to 7, wherein, After step S4, it further includes: machining the area with the surface functional layer to the designed size, and making the final thickness of the surface functional layer 1.0-1.5 mm; and performing color detection of the extrusion cone die after machining to detect whether there is a defect.

9. Application of the alloy powder for repairing the GH4169 extrusion cone die as claimed in claim 1 or 2 in the repair of copper alloy extrusion dies.

10. Application of the composite repair method for the GH4169 extrusion cone die as claimed in any one of claims 3 to 8 in the repair of copper alloy extrusion dies.

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