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CN-122007413-A - High-strength nonmagnetic alloy and manufacturing method thereof

CN122007413ACN 122007413 ACN122007413 ACN 122007413ACN-122007413-A

Abstract

The invention relates to the technical field of hard alloy, in particular to a manufacturing method of a high-strength nonmagnetic alloy, which comprises the following steps of S1, preprocessing WC powder, surface activation, S2, dispersing the activated WC powder in a Ti-Si-C precursor solution, carrying out adsorption loading, solvent evaporation curing and in-situ pyrolysis reaction, generating a metallurgically bonded Ti-Si-C coating layer on the surface of the WC powder in situ to obtain WC-Ti-Si-C composite powder, S3, mixing the WC-Ti-Si-C composite powder, metal Ni powder and a forming agent according to a preset proportion to obtain a homogeneous composite mixture, and S4, carrying out cold isostatic pressing forming on the composite mixture to obtain a green compact, and then carrying out low-temperature degreasing and in-situ reaction presintering treatment to obtain a presintered green body. The invention makes the wetting angle of the Ti-Si active layer rich in Si on the outer layer and the Ni liquid phase less than or equal to 5 degrees at the sintering temperature through the construction of the coating layer, approaches to complete wetting, can solve the problem of insufficient wettability of Ni to WC, and avoids agglomeration and segregation of the Ni liquid phase in the sintering process so as to eliminate the defects of nickel pool and coarse holes.

Inventors

  • FU HUI
  • LI JINLING
  • He Xiaochong
  • WU TINGCHANG
  • ZHOU JILI
  • LI KEHUA

Assignees

  • 河源普益硬质合金厂有限公司

Dates

Publication Date
20260512
Application Date
20260409

Claims (10)

  1. 1. A method for manufacturing a high strength nonmagnetic alloy, comprising the steps of: S1, pretreatment and surface activation of WC powder Sequentially performing alkali washing impurity removal, acid washing activation and vacuum drying treatment on the WC powder to obtain activated WC powder with active dangling bonds on the surface; S2, construction of coating layer Dispersing activated WC powder in Ti-Si-C precursor solution, and carrying out adsorption loading, solvent evaporation curing and in-situ pyrolysis reaction to generate a metallurgically bonded Ti-Si-C coating on the surface of the WC powder in situ to obtain WC-Ti-Si-C composite powder; s3, batching and homogenizing the mixture Mixing WC-Ti-Si-C composite powder, metal Ni powder and a forming agent according to a preset proportion, and performing wet ball milling, vacuum drying and sieving treatment to obtain a homogeneous composite material; S4, presintering by molding and degreasing and in-situ reaction Cold isostatic pressing is carried out on the composite material to obtain a green body, and then low-temperature degreasing and in-situ reaction presintering treatment are sequentially carried out to obtain a presintered green body; s5, densification by low-pressure liquid phase sintering Placing the presintered blank in a low-pressure sintering furnace, and performing low-pressure liquid phase sintering in an argon atmosphere to obtain a near-full-compact sintered blank; S6, solid solution and aging heat treatment And sequentially carrying out vacuum solution treatment and aging treatment on the sintered blank to obtain a finished product.
  2. 2. The method for manufacturing the high-strength nonmagnetic alloy according to claim 1, wherein in S1, the particle size of WC powder is 0.2-1.0 μm, the total carbon content is 6.08-6.18 wt%, the free carbon content is less than or equal to 0.08wt% and the oxygen content is less than or equal to 500ppm, the alkaline washing impurity is performed by using a sodium hydroxide aqueous solution with the mass fraction of 3-8%, the treatment condition is 40-60 ℃ ultrasonic stirring for 20-40 min, the pickling activation is performed by using a dilute hydrochloric acid solution with the mass fraction of 2-5%, the treatment condition is stirring for 15-30 min at room temperature, the vacuum drying temperature is 70-90 ℃, and the drying time is 10-15 h.
  3. 3. The method for producing a high-strength nonmagnetic alloy according to claim 1, wherein in S2, the Ti-Si-C precursor solution contains a titanium source, a silicon source, a carbon source and a chelating agent in a molar ratio of (2-4) to (0.5-1.5) to (1-3), wherein the chelating agent is added in an amount of 0.3-0.8% based on the total mass of the precursor solution, the titanium source is at least one of tetrabutyl titanate and isopropyl titanate, the silicon source is at least one of tetraethyl orthosilicate and a silane coupling agent, the carbon source is at least one of anhydrous glucose, sucrose and a thermosetting phenol resin, and the chelating agent is at least one of citric acid and ethylenediamine tetraacetic acid.
  4. 4. The method for manufacturing the high-strength nonmagnetic alloy according to claim 1, wherein in S2, the adsorption load treatment condition is argon protection, ultrasonic stirring is carried out at 40-60 ℃ for 1-3 hours, the liquid-solid ratio of the precursor solution to the activated WC powder is (4-8) to 1, the in-situ pyrolysis treatment condition is high-purity argon protection, the temperature rising rate is increased to 750-850 ℃ at 3-8 ℃ per minute, the temperature is kept for 1-3 hours, the total thickness of the Ti-Si-C coating layer is 30-200 nm, and the mass of the coating layer accounts for 0.5-3.5% of the total mass of the WC-Ti-Si-C composite powder.
  5. 5. The method for manufacturing a high-strength nonmagnetic alloy according to claim 1, wherein in S3, the mass fraction of each raw material is 85-94% of WC-Ti-Si-C composite powder, 6-15% of metal Ni powder and 0.1-0.3% of forming agent, wherein the metal Ni powder is carbonyl Ni powder, the particle size is 1-3 μm, the oxygen content is less than or equal to 800ppm, and the forming agent is at least one of paraffin and polyethylene glycol.
  6. 6. The method for manufacturing the high-strength nonmagnetic alloy according to claim 1, wherein in the step S3, the ball-to-material ratio of wet ball milling is (4-6) to 1, the grinding medium is absolute ethyl alcohol, the ball milling speed is 200-300 rpm, the ball milling time is 12-18 h, the vacuum drying temperature is 70-90 ℃, the drying time is 10-15 h, and the sieving treatment adopts a 200-300 mesh standard sieve.
  7. 7. The method of manufacturing a high strength nonmagnetic alloy according to claim 1, wherein in S4, the cold isostatic pressing pressure is 180-220 MPa, the dwell time is 20-40S, the green density is 58-62% of the theoretical density, the low temperature degreasing treatment condition is high purity argon protection, the temperature is raised to 400-500 ℃ at a temperature rise rate of 1-3 ℃ per minute, the temperature is kept for 60-120 minutes, the in-situ reaction pre-sintering treatment condition is that the vacuum degree is less than or equal to 10 -1 Pa, the temperature is raised to 1150-1250 ℃ at a temperature rise rate of 3-8 ℃ per minute, and the temperature is kept for 60-90 minutes.
  8. 8. The method for manufacturing the high-strength nonmagnetic alloy according to claim 1, wherein in S5, the specific process of low-pressure liquid phase sintering is that vacuum is firstly pumped to be less than or equal to 10 -2 Pa, the temperature is increased to 1380-1440 ℃ at the heating rate of 8-12 ℃ per minute, the pressure in a high-purity argon gas control furnace is 3-10 MPa, the temperature and the pressure are maintained for 45-90 minutes, the temperature is reduced to 800 ℃ at the speed of 10-20 ℃ per minute, and the temperature is cooled to room temperature along with the furnace.
  9. 9. The method for manufacturing the high-strength nonmagnetic alloy according to claim 1, wherein in the step S6, the solid solution treatment is performed by heating to 1050-1150 ℃ at a heating rate of 8-12 ℃ per min under the protection of high-purity argon gas, maintaining the temperature for 60-150 min, and quenching the high-purity argon gas to room temperature, and the aging treatment is performed by heating to 450-550 ℃ at a heating rate of 3-8 ℃ per min, maintaining the temperature for 120-240 min, and cooling to room temperature with a furnace.
  10. 10. A high-strength nonmagnetic alloy, characterized by being produced by the production method of a high-strength nonmagnetic alloy as set forth in any one of claims 1 to 9.

Description

High-strength nonmagnetic alloy and manufacturing method thereof Technical Field The invention relates to the technical field of hard alloy, in particular to a high-strength nonmagnetic alloy and a manufacturing method thereof. Background WC-Ni cemented carbide takes WC as a hard phase and metallic Ni as a binding phase, has excellent high-temperature oxidation resistance and corrosion resistance, can realize no magnetism at room temperature under the low-carbon condition, and is widely applied to the fields of magnetic material forming dies, electronic precision manufacturing, medical equipment and the like; However, the prior WC-Ni alloy has two problems in actual production: The intrinsic wettability of Ni to WC is far worse than that of Co, the wetting angle of a WC/Ni system is up to 20-35 degrees at 1400 ℃ liquid phase sintering temperature, and Ni liquid phase is easy to flow aggregation and offset aggregation in the sintering process, so that 'nickel pool' defects and coarse holes are formed, and the strength, impact resistance and batch stability of the alloy are seriously deteriorated; The solubility of W and C in Ni is far higher than Co, so that the two-phase stable carbon window of WC-Ni alloy is about 0.1-0.2 wt%, and is only 1/5 of that of WC-Co system, and tiny fluctuation of carbon content in sintering process can lead to precipitation of eta phase or free graphite, resulting in broken cliff type reduction of alloy strength, and meanwhile, the core premise of realizing non-magnetism of WC-Ni alloy is that the bonding phase Ni is dissolved with enough W to reduce Curie temperature, and the W solid solution is highly dependent on low-carbon environment, so that dead cycle of 'needing no magnetism and easily yielding eta phase reduced strength with low carbon' is formed, and non-magnetism and high strength cannot be simultaneously achieved. Aiming at the problems, the prior art generally adopts a mode of coating WC powder with Ni to improve the dispersibility of Ni, but can only relieve the agglomeration problem, can not intrinsically reduce the solid-liquid interface energy, improve the wettability and thoroughly eliminate the defect of a nickel pool, and aims at the contradiction between carbon control and non-magnetic property, cr and Mo are adopted to alloy to widen a carbon window and reduce the Curie temperature, but alloying elements are not cooperated with wettability regulation and control and carbon control, can not get rid of the dependence on W solid solution, can not fundamentally decouple the binding relation between non-magnetic property and low carbon, and has higher carbon control difficulty and low qualification rate. In view of the above, the present invention provides a method for manufacturing a high-strength nonmagnetic alloy to solve the above-mentioned problems. Disclosure of Invention In order to achieve the above purpose, the invention provides a manufacturing method of a high-strength nonmagnetic alloy, which comprises the following steps: S1, pretreatment and surface activation of WC powder Sequentially performing alkali washing impurity removal, acid washing activation and vacuum drying treatment on the WC powder to obtain activated WC powder with active dangling bonds on the surface; S2, construction of coating layer Dispersing activated WC powder in Ti-Si-C precursor solution, and carrying out adsorption loading, solvent evaporation curing and in-situ pyrolysis reaction to generate a metallurgically bonded Ti-Si-C coating on the surface of the WC powder in situ to obtain WC-Ti-Si-C composite powder; s3, batching and homogenizing the mixture Mixing WC-Ti-Si-C composite powder, metal Ni powder and a forming agent according to a preset proportion, and performing wet ball milling, vacuum drying and sieving treatment to obtain a homogeneous composite material; S4, presintering by molding and degreasing and in-situ reaction Cold isostatic pressing is carried out on the composite material to obtain a green body, and then low-temperature degreasing and in-situ reaction presintering treatment are sequentially carried out to obtain a presintered green body; s5, densification by low-pressure liquid phase sintering Placing the presintered blank in a low-pressure sintering furnace, and performing low-pressure liquid phase sintering in an argon atmosphere to obtain a near-full-compact sintered blank; S6, solid solution and aging heat treatment And sequentially carrying out vacuum solution treatment and aging treatment on the sintered blank to obtain a finished product. Preferably, in the S1, the particle size of WC powder is 0.2-1.0 mu m, the total carbon content is 6.08-6.18 wt%, the free carbon content is less than or equal to 0.08wt% and the oxygen content is less than or equal to 500ppm, the alkaline washing impurity removal is performed by adopting a sodium hydroxide aqueous solution with the mass fraction of 3-8%, the treatment condition is that ultrasonic stirring is pe