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CN-122007423-A - Cemented carbide ball tooth with gradient structure suitable for dry rock breaking and preparation method

CN122007423ACN 122007423 ACN122007423 ACN 122007423ACN-122007423-A

Abstract

The invention provides a hard alloy button with a gradient structure suitable for dry rock breaking and a preparation method, wherein the hard alloy button is of an N-layer gradient structure, raw materials of the gradient structure comprise WC powder, co powder and graphene powder, the volume fraction of the WC powder and the volume fraction of the graphene powder in the N-layer gradient structure are equal or increased layer by layer from an inner layer to an outer layer, the volume fraction of the Co powder is equal or reduced layer by layer from the inner layer to the outer layer, the volume fractions of the WC powder and the graphene powder in the outermost layer of the N-layer gradient structure are both larger than the volume fraction of the Co powder, and the thickness of each layer in the N-layer gradient structure is larger than or equal to 0.1mm. The hard alloy ball tooth not only improves the mechanical property of the hard alloy ball tooth, but also has high hardness and high toughness, and endows the hard alloy ball tooth with more excellent heat dissipation, thereby greatly improving the rock breaking efficiency and prolonging the service life of products.

Inventors

  • JIN XIN
  • WEI HONGCHAO
  • SONG HAITAO
  • NIE CHAO
  • WU XINKAI

Assignees

  • 中煤科工西安研究院(集团)有限公司

Dates

Publication Date
20260512
Application Date
20260122

Claims (10)

  1. 1. The hard alloy spherical tooth is characterized in that the structure of the hard alloy spherical tooth is an N-layer gradient structure, and raw materials of the gradient structure comprise WC powder, co powder and graphene powder; In the N-layer gradient structure, the volume fraction of WC powder and the volume fraction of graphene powder are equal or increased layer by layer from the inner layer to the outer layer, and the volume fraction of Co powder is equal or reduced layer by layer from the inner layer to the outer layer; The thickness of each layer in the N-layer gradient structure is more than or equal to 0.1mm.
  2. 2. The cemented carbide button with the gradient structure suitable for dry rock breaking as claimed in claim 1, wherein the total thickness of the gradient structure with the N layer being more than or equal to 4;N layers is 0.4-25 mm.
  3. 3. The cemented carbide button with the gradient structure suitable for dry rock breaking according to claim 1, wherein the average grain size of WC powder is 0.5-2.0 μm, the average grain size of Co powder is 0.3-1.5 μm, and the average grain size of graphene powder is 0.2-1.0 μm.
  4. 4. A method for producing a cemented carbide button of gradient construction suitable for dry rock breaking according to any one of claims 1 to 3, characterized in that the method comprises in particular the following steps: step one, batching and mixing: Mixing WC powder, co powder and graphene powder, then placing the mixture into a mixer, adding a binder and water, stirring the mixture uniformly to obtain a group of mixture, and preparing N groups of mixture with different proportions by using the same method; Step two, establishing a model: establishing a 3D model of the cemented carbide buttons with the N-layer gradient structure in a computer, setting printing parameters for the 3D model, and then introducing the 3D model into a slurry direct-writing modeling 3D printer to obtain the set slurry direct-writing modeling 3D printer; printing a green body: respectively taking the N groups of mixtures obtained in the step one as printing materials, and printing by adopting the set slurry direct-writing modeling 3D printer obtained in the step two to obtain N groups of green bodies with different proportions; Step four, de-binding agent: Placing the N groups of green bricks with different proportions obtained in the step three into a degreasing furnace, setting heating rate, heat preservation temperature and heat preservation time, and then performing hydrogen reduction to remove the binder to obtain N degreased sheets; step five, two-step vacuum sintering: And (3) sequentially assembling the N degreased sheets obtained in the step (IV) into a sintering die from the inner layer to the outermost layer according to the design layer number and sequence, performing two-step vacuum sintering, and cooling along with a furnace after the sintering is finished to obtain the cemented carbide spherical tooth with the N-layer gradient structure.
  5. 5. The method for preparing the cemented carbide buttons with the gradient structure suitable for dry rock breaking according to claim 4, wherein in the first step, the solid content of the N groups of mixtures is 45-75wt%; In the first step, the mass ratio of the sum of the total mass of the WC powder, the Co powder and the graphene powder to the binder is (4-9): 1.
  6. 6. The cemented carbide ball tooth with the gradient structure suitable for dry rock breaking according to claim 4, wherein in the first step, the volume fraction ratio of WC powder to Co powder to graphene powder is (60-90%) (2-30%) (0-10%).
  7. 7. The method for preparing the cemented carbide button with the gradient structure suitable for dry rock breaking as claimed in claim 4, wherein in the first step, in the N groups of mixtures, the binder in each group of mixtures is prepared from 15-25% by mass of guar gum, 5-15% by mass of polyphenyl ether, 3-10% by mass of dodecyl trimethyl ammonium chloride and the balance of styrene thermoplastic elastomer, and the sum of the mass fractions of the components is 100%.
  8. 8. The method for preparing the cemented carbide button with the gradient structure suitable for dry rock breaking according to claim 4, wherein in the second step, the printing parameters are specifically that the printing speed is 10-350 mm/s, the printing layer thickness is 0.1-0.5 mm, the printing temperature is 100-380 ℃, and the nozzle temperature is 100-260 ℃.
  9. 9. The preparation method of the hard alloy buttons with the gradient structure suitable for dry rock breaking is characterized by comprising the specific steps of heating to 80-150 ℃ from room temperature at a heating rate of 4-7 ℃ per minute, preserving heat for 0.5-1 h, heating to 230-290 ℃ at a heating rate of 3-8 ℃ per minute, preserving heat for 2-2.5 h, heating to 380-420 ℃ at a heating rate of 2.5-4 ℃ per minute, preserving heat for 1-1.5 h, and finally heating to 580-650 ℃ at a heating rate of 2-3 ℃ per minute, and preserving heat for 1.5-2 h in a hydrogen reduction debinding process.
  10. 10. The method for preparing the cemented carbide buttons with the gradient structure suitable for dry rock breaking according to claim 4 is characterized by comprising the specific steps of firstly placing a sintering mold assembled with N degreased thin sheets into a vacuum sintering furnace, adopting nitrogen as a pressure medium, heating to 750-1150 ℃ and carrying out heat preservation and sintering for 30-90 min, wherein the sintering pressure is 1-15 MPa, cooling a sample to be sintered, continuing to carry out second-step sintering, wherein the sintering temperature of the second-step sintering is 1250-1500 ℃, the sintering pressure is 1-15 MPa, and the sintering time is 30-70 min.

Description

Cemented carbide ball tooth with gradient structure suitable for dry rock breaking and preparation method Technical Field The invention belongs to the technical field of powder metallurgy, relates to a hard alloy ball tooth, and in particular relates to a hard alloy ball tooth with a gradient structure suitable for dry rock breaking and a preparation method thereof. Background The hard alloy is a composite material prepared by taking refractory metal compound as a matrix and transition metal as a binding phase through a powder metallurgy method, and has the advantages of high hardness, high strength, high wear resistance, stable chemical property and the like. In recent years, with the development of mines, energy exploitation and major infrastructure construction, the demand of mining products such as cemented carbide drills at home and abroad is increasing. Under the working environment of coal mine and the like needing dry rock breaking, the drill bit can not only be subjected to the combined action of various stresses such as stretching and compression in the rock breaking process, so that high requirements are put forward on the hardness and impact toughness of the drill bit, but also the drill bit can fail due to the fact that the drill bit cannot timely dissipate heat when the temperature is too high. Therefore, a hard alloy button which not only meets the requirements of high hardness and high toughness, but also can radiate heat in time is required to be developed to solve the problems encountered in the dry rock breaking process. The cemented carbide ball tooth with the gradient structure presents gradient distribution of cobalt on the tissue structure, has high hardness and good wear resistance due to higher content of WC in the surface layer, and has higher cobalt content and good toughness closer to the inside of the cemented carbide ball tooth, and the cemented carbide ball tooth can bear higher load before being damaged in the rock drilling process, so that the contradiction between toughness and wear resistance is well solved, and the cemented carbide ball tooth is widely focused. However, the existing hard alloy buttons with the gradient structure are mainly prepared by a carburization method, and the popular processes comprise carburization of a carbon-deficient alloy and carburization of a low-carbon alloy, but the defects of the two methods are obvious, the core technology of the carbon-deficient method is distributed control of eta phase, the stability and the repeatability risk of the process are high, and the low-carbon method relies on accurate control of process equipment, so that a novel method for preparing the hard alloy buttons with the gradient structure is developed, and has important significance for improving the application of the gradient hard alloy buttons. Disclosure of Invention Aiming at the defects existing in the prior art, the invention aims to provide the hard alloy spherical tooth with the gradient structure suitable for dry rock breaking and the preparation method thereof, and solves the technical problems that the stability of the process is improved and the severity of the reaction condition is reduced when the hard alloy spherical tooth with the gradient structure for dry rock breaking is prepared in the prior art, and the stability and the severity of the reaction condition are difficult to obtain. In order to solve the technical problems, the invention is realized by adopting the following technical scheme. The hard alloy ball tooth is of an N-layer gradient structure, and raw materials of the gradient structure comprise WC powder, co powder and graphene powder. In the N-layer gradient structure, the volume fraction of WC powder and the volume fraction of graphene powder are equal or increased layer by layer from the inner layer to the outer layer, the volume fraction of Co powder is equal or reduced layer by layer from the inner layer to the outer layer, and in the outermost layer of the N-layer gradient structure, the volume fractions of WC powder and graphene powder are both larger than the volume fraction of Co powder. The thickness of each layer in the N-layer gradient structure is more than or equal to 0.1mm. The invention also has the following technical characteristics. Specifically, the total thickness of the 4;N-layer gradient structure is 0.4-25 mm. Specifically, the average particle size of the WC powder is 0.5-2.0 mu m, the average particle size of the Co powder is 0.3-1.5 mu m, and the average particle size of the graphene powder is 0.2-1.0 mu m. The invention also discloses a preparation method of the hard alloy spherical tooth with the gradient structure suitable for dry rock breaking, which specifically comprises the following steps. Step one, batching and mixing: Mixing WC powder, co powder and graphene powder, then placing the mixture into a mixer, adding a binder and water, stirring the mixture uniformly to obtain a group of mixture, and