A light-weight gradient cemented carbide and a method of manufacturing the same

Abstract

The application discloses a light gradient cemented carbide and a manufacturing method thereof, and relates to the technical field of cemented carbide preparation. The cemented carbide comprises working parts and non-working parts which are sintered together and different in composition. The working parts are metal ceramic cemented carbide materials which are composed of the following components in percentage by weight: titanium carbonitride 35-45%, tungsten carbide 10-20%, tantalum carbide or niobium carbide 15%, molybdenum carbide 5% and nickel 15-25%. The non-working parts are light cemented carbide materials which are composed of the following components in percentage by weight: titanium carbide powder 40-60%, tungsten carbide powder 22-50% and nickel powder or cobalt powder 15-18%. The application has the advantages of reasonable design, large-scale continuous production under the conditions of saving tungsten resources, reducing raw material cost, producing products without deformation and obtaining stable size, and adaptability to different types of cemented carbide products except sealing rings, so that the material has broad spectrum.

Description

Technical Field

[0001] This invention relates to the field of cemented carbide preparation technology, and more specifically to the field of lightweight gradient cemented carbide and its manufacturing method. Background Technology

[0002] Cemented carbide is an alloy material made from hard compounds of refractory metals and a binder metal through powder metallurgy. Cemented carbide possesses a series of excellent properties, including high hardness, wear resistance, good strength and toughness, heat resistance, and corrosion resistance. Its high hardness and wear resistance are particularly noteworthy, remaining essentially unchanged even at 500℃, and retaining high hardness at 1000℃. Cemented carbide is widely used as a cutting tool material, such as for turning tools, milling cutters, planing tools, drill bits, and boring tools, for cutting cast iron, non-ferrous metals, plastics, synthetic fibers, graphite, glass, stone, and ordinary steel. It can also be used to cut difficult-to-machine materials such as heat-resistant steel, stainless steel, high-manganese steel, and tool steel. Existing patents disclose the following technologies:

[0003] The patent with publication number CN102434665A, entitled "A Lightweight Gradient Hard Alloy Sealing Ring and Its Manufacturing Method," discloses the following: A lightweight gradient hard alloy sealing ring and its manufacturing method, wherein the sealing ring consists of a working part and a non-working part; the working part is composed of 90-94% by weight tungsten carbide and 6-10% by weight nickel or cobalt, with a layer thickness of 1.0-2.5 mm; the non-working part is composed of 40-60% by weight titanium carbide powder, 10-18% by weight nickel powder, and 22-50% by weight tungsten carbide powder; during pressing, the hard alloy material for the working part is first weighed, added to a steel mold and leveled, then the lightweight hard alloy material for the non-working part is weighed, added to a steel mold and leveled, pressure is applied and pressed into shape, and then placed in a furnace for sintering to obtain a gradient hard alloy sealing ring with two different compositions. The advantages are: compared with hard alloy sealing rings made entirely of tungsten carbide, nickel or cobalt, the density is reduced, tungsten resources are saved, and the cost is low; it can be used in pump or vessel seals or bushings.

[0004] Compared with cemented carbide sealing rings made entirely of tungsten carbide (WC), nickel, or cobalt (Ni or Co), the density of cemented carbide sealing rings prepared by the process method disclosed in the above patent is reduced from 14.5-15.0 (g / cm³) to 7.8-9.5 (g / cm³), saving more than 50% (by weight) of tungsten resources and 30%-60% of raw material costs, while not changing the usage requirements and quality performance of conventional tungsten carbide (WC), nickel, or cobalt (Ni or Co) cemented carbide sealing rings. However, the cemented carbide sealing rings prepared by the above patent have the following defects: (1) The density difference between the working part and the non-working part is too large, and the density cannot be made consistent by adjusting the formula, resulting in a large difference in the shrinkage ratio of the finished product after sintering, making it difficult to obtain a stable and definite finished product and making it impossible to carry out large-scale production; (2) It limits the scope of application of the present invention and is only suitable for the preparation of sealing rings. Summary of the Invention

[0005] The purpose of this invention is to address the technical problem of excessive density differences between the working and non-working parts of existing cemented carbide sealing rings, which cannot be reconciled by adjusting the formula. This leads to significant differences in the shrinkage ratio of the finished product after sintering, making it difficult to obtain a stable and dimensional product and hindering mass production. This invention provides a lightweight gradient cemented carbide and its manufacturing method. Under the conditions of conserving tungsten resources and reducing raw material costs, and ensuring that the produced product does not deform and achieves stable dimensions, continuous large-scale production is possible. Furthermore, in addition to sealing rings, it can be adapted to different types of cemented carbide products, making this material versatile.

[0006] To achieve the above objectives, the present invention specifically adopts the following technical solution:

[0007] This invention provides a lightweight gradient cemented carbide, comprising a working part and a non-working part with different compositions but the same density. The working part is a cermet cemented carbide material, which is composed of the following components by weight percentage: 35%-45% titanium carbide, 10%-20% tungsten carbide, 15% tantalum carbide or niobium carbide, 5% molybdenum carbide, and 15%-25% nickel.

[0008] The non-working part is made of lightweight cemented carbide material, which is composed of the following components by weight percentage: 40%-60% titanium carbide powder, 22%-50% tungsten carbide powder, and 15%-18% nickel powder or cobalt powder.

[0009] Specifically, based on existing technology, this solution aims to make the working and non-working parts have the same density by adjusting the formula, thereby preventing deformation caused by inconsistent shrinkage of the sintered product. The original hard alloy material composed of tungsten carbide, nickel, or cobalt in the working part is replaced with a metal-ceramic hard alloy material.

[0010] In one embodiment, the thickness of the working part is 1-2.5 mm.

[0011] In one embodiment, the working part is a cermet cemented carbide material, which is composed of the following components by weight percentage: 45% titanium carbide, 10% tungsten carbide, 15% tantalum carbide or niobium carbide, 5% molybdenum carbide, and 25% nickel;

[0012] The non-working part is made of lightweight cemented carbide material, which is composed of the following components by weight percentage: 46% titanium carbide powder, 36% tungsten carbide powder, and 18% nickel or cobalt powder.

[0013] In one embodiment, the working part is a cermet cemented carbide material, which is composed of the following components by weight percentage: 40% titanium carbide, 20% tungsten carbide, 15% tantalum carbide or niobium carbide, 5% molybdenum carbide, and 20% nickel;

[0014] The non-working part is made of lightweight cemented carbide material, which is composed of the following components by weight percentage: 40% titanium carbide powder, 45% tungsten carbide powder, and 15% nickel or cobalt powder.

[0015] During pressing, first weigh the metal-ceramic cemented carbide material used in the working part, add it to the steel mold and flatten it, then weigh the lightweight cemented carbide material used in the non-working part, add it to the steel mold and flatten it, apply pressure and press it into shape, and put the shaped product into the furnace for sintering. The sintered product obtained forms a gradient cemented carbide product with two different compositions.

[0016] In one embodiment, the working part and the non-working part have the same density.

[0017] In one embodiment, the tungsten carbide in the non-working part is electrolytic tungsten carbide powder recycled from waste cemented carbide or crushed waste cemented carbide powder.

[0018] Another aspect of the present invention provides a method for manufacturing a lightweight gradient cemented carbide, using the aforementioned lightweight gradient cemented carbide, comprising the following steps:

[0019] S1. Prepare the metal-ceramic hard alloy mixture for the working part, and calculate the density value of the working part based on the percentage content of each component in the working part formula and the density of its components.

[0020] S2. Prepare a lightweight hard alloy mixture for the non-working part. Calculate the density value of the non-working part based on the percentage content and density of each component in the non-working part formula. Adjust the percentage of each component in the non-working part appropriately based on the density value of the working part in step S1, and finally make the density of the working part consistent with the density value of the non-working part.

[0021] S3. Compression molding of working and non-working parts:

[0022] S31. Since the density of the metal-ceramic hard alloy mixture in the working part and the light hard alloy mixture in the non-working part are the same, their shrinkage coefficients are also the same. There is no need to change the shape of the pressed blank. It is only necessary to design the shape of the pressed blank to be consistent with the shape of the sintered blank.

[0023] S32. First, weigh and add the metal-ceramic hard alloy mixture obtained in step S1 to the working part in the steel mold, and level it; then weigh and add the lightweight hard alloy mixture obtained in step S2 to the non-working part, and level it; apply 60-100MPa / cm² to the steel mold for pressing and molding to obtain the processed pressed product.

[0024] S4. The pressed products obtained in step S32 are sintered and put into storage after passing inspection.

[0025] Specifically: In this scheme, the working part uses a metal-ceramic hard alloy material, while the non-working part uses a lightweight hard alloy material. The densities of the two parts are similar, and by adjusting the formula, it is easy to make their densities consistent. Therefore, the advantages of this process are: (1) it retains the advantages of the "Lightweight Gradient Hard Alloy Sealing Ring"; (2) it produces sintered products with consistent shrinkage and no deformation, which is easy to carry out large-scale production; (3) the products prepared by this new material have a broad spectrum.

[0026] In one implementation, step S1 includes the following specific steps:

[0027] S11. The working part is weighed with the following components by weight percentage: 35%-45% titanium carbide, 10%-20% tungsten carbide, 15% tantalum carbide or niobium carbide, 5% molybdenum carbide and 15%-25% nickel, and then the above components are mixed evenly to obtain a mixture.

[0028] S12. Place the mixture obtained in step S11 into a ball mill for wet milling, wherein the ball-to-material ratio is 4:1 and the solid-to-liquid ratio is 1Kg / 300ml. Mill at room temperature for 24 hours to obtain wet material.

[0029] S13. After recovering the alcohol from the ground wet material obtained in step S12 using a vacuum dryer, the material is then dried in a steam drying oven to obtain dry powder.

[0030] S14. Add SD adhesive or gasoline rubber liquid molding agent to the dry powder obtained in step S13 and stir evenly for 2 minutes. The amount of adhesive added is 100-110 ml / Kg. Sieve through a 60-100 mesh sieve to obtain the metal-ceramic hard alloy mixture for the working part.

[0031] In one implementation, step S2 includes the following specific steps:

[0032] S21. The non-working part is composed of the following components by weight percentage: 40%-60% titanium carbide powder, 22%-50% tungsten carbide powder, and 15%-18% nickel powder. The density value of the non-working part is calculated by taking values ​​within this range. The component percentage of the non-working part is adjusted to make the density values ​​of the working part and the non-working part consistent. The mixture is obtained by uniformly mixing the components with the adjusted weight percentage of the non-working part.

[0033] S22. Place the mixture obtained in step S21 into a ball mill for wet milling. The ball-to-material ratio is 4:1 and the solid-to-liquid ratio is 1 kg / 300 ml. Mill at room temperature for 24 hours to obtain wet material.

[0034] S23. After recovering the alcohol from the ground wet material obtained in step S22 using a vacuum dryer, it is then dried in a steam drying oven to obtain dry powder.

[0035] S24. Add SD adhesive or gasoline rubber liquid molding agent to the dry powder obtained in step S23 and stir evenly for 2 minutes. The amount of adhesive added is 120 ml / Kg. Sieve through a 60-100 mesh sieve to obtain the lightweight hard alloy mixture for the non-working part.

[0036] In one implementation, step S4 includes the following specific steps:

[0037] S41. Add the pressed product obtained in step S32 into a vacuum furnace for sintering. The temperature inside the vacuum furnace is controlled at 1420-1500℃ and held for 2-3 hours to obtain the sintered product.

[0038] S42. Grind the surface of the product obtained in step S41 according to the dimensional accuracy requirements, and put it into storage after passing the inspection.

[0039] The beneficial effects of this invention are as follows:

[0040] 1. This invention enables continuous large-scale production while conserving tungsten resources and reducing raw material costs, and while ensuring that the produced products do not deform and have stable dimensions. Moreover, in addition to sealing rings, it can also be adapted to different types of cemented carbide products, making this type of material versatile.

[0041] 2. The working part of the present invention uses a metal-ceramic hard alloy material, and the non-working part uses a lightweight hard alloy material. The densities of the two parts are similar, and by adjusting their formulas, it is easy to make their densities consistent. Therefore, the advantages of this process method are: (1) it retains the advantages of the "Lightweight Gradient Hard Alloy Sealing Ring"; (2) it prepares sintered products with consistent shrinkage and no deformation, which is easy to carry out large-scale production; (3) the products prepared by this new material have a broad spectrum. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of a lightweight gradient hard alloy sealing ring blank.

[0043] Figure 2 This is a schematic diagram of a sintered blank for a lightweight gradient hard alloy sealing ring.

[0044] Figure 3 This is a schematic diagram of a lightweight gradient cemented carbide wear-resistant long strip compact.

[0045] Figure 4 This is a schematic diagram of a lightweight gradient cemented carbide wear-resistant long strip sintered billet. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0047] Example 1

[0048] This embodiment provides a lightweight gradient cemented carbide, comprising working and non-working parts sintered together with different compositions;

[0049] The working part is a cermet-ceramic cemented carbide material, which is composed of the following components by weight percentage: 45% titanium carbide, 10% tungsten carbide, 15% tantalum carbide or niobium carbide, 5% molybdenum carbide, and 25% nickel; the density of the working part is denoted as ρ1, and the formula for calculating the density value of the working part is:

[0050] ρ1 = 1 / (Percentage of titanium carbide / density of titanium carbide + percentage of tungsten carbide / density of tungsten carbide + percentage of tantalum carbide or niobium carbide / density of tantalum carbide or niobium carbide + percentage of molybdenum carbide / density of molybdenum carbide + percentage of nickel / density of nickel).

[0051] Of which, titanium carbonitride (TiCN) accounts for 45% and has a density of 5.08 g / cm³.

[0052] The percentage of tungsten carbide (WC) is 10%, and the density of tungsten carbide (WC) is 15.7 g / cm³.

[0053] The percentage of tantalum carbide or niobium carbide (Ta(Nb)C) is 15%, and the density of tantalum carbide or niobium carbide (Ta(Nb)C) is 14.3 g / cm³.

[0054] The percentage of molybdenum carbide (Mo2C) is 5%, and the density of molybdenum carbide (Mo2C) is 9.18 g / cm³.

[0055] The percentage of nickel (Ni) is 25%, and the density of nickel (Ni) is 8.9 g / cm³.

[0056] Therefore, ρ1 = 1 / (0.45 / 5.08 + 0.1 / 15.7 + 0.15 / 14.3 + 0.05 / 9.18 + 0.25 / 8.9) = 7.2 g / cm³

[0057] The non-working part is made of lightweight cemented carbide material, which is composed of the following components by weight percentage: 46% titanium carbide powder, 36% tungsten carbide powder, and 18% nickel powder. The tungsten carbide in the non-working part is either electrolytic tungsten carbide powder from recycled waste cemented carbide or crushed waste cemented carbide powder. The density of the non-working part is denoted as ρ2, and the formula for calculating the density value of the non-working part is:

[0058] ρ2 = 1 / (Percentage of titanium carbide powder / Density of titanium carbide powder + Percentage of tungsten carbide powder / Density of tungsten carbide powder + Percentage of nickel powder / Density of nickel powder)

[0059] The titanium carbide powder (TiC powder) accounts for 46% of the total content, and the density of the titanium carbide powder (TiC powder) is 4.93 g / cm³.

[0060] The percentage of tungsten carbide powder (waste WC-Co powder) is 36%, and the density of tungsten carbide powder (waste WC-Co powder) is 14.1 g / cm³.

[0061] The percentage of nickel powder or cobalt powder (Ni powder or Co powder) is 18%, and the density of nickel powder or cobalt powder (Ni powder or Co powder) is 8.9 g / cm³.

[0062] Therefore, ρ2 = 1 / (0.46 / 4.93 + 0.36 / 14.1 + 0.18 / 8.9) = 7.2 g / cm³.

[0063] The preparation method of this lightweight gradient cemented carbide is as follows:

[0064] Weigh and mix all the above components according to the weight ratio. Place the mixtures from the working and non-working parts into separate ball mills for wet grinding, with a ball-to-material ratio of 4:1 and a solid-to-liquid ratio of 1 kg / 300 ml. Grind at room temperature for 24 hours. After removing the alcohol from the ball-milled working and non-working parts, dry them separately using a vacuum dryer (Z-type mixer) and a steam dryer. Add SD adhesive (or gasoline-based rubber liquid) molding agent to the dried powder and stir evenly (2 minutes). Add 100-110 ml / kg of adhesive to the working part powder and 120 ml / kg to the non-working part powder. Sieve through a 60-100 mesh sieve. Weigh 16.8 g of the working part powder, place it in a steel mold and level it. Then weigh 102 g of the non-working part powder, add it to the steel mold and level it. Apply pressure of 60-100 MPa / cm² to press and shape the compact. The pressed blank should have the shape shown in the image. Figure 1 As shown (the pressed blank has a ring-shaped structure, with an inner diameter d=79.37mm, an inner diameter D=108.13mm, a total thickness H=19mm, and a working part thickness h=3.13mm); the above-mentioned press-formed blank is placed in a vacuum furnace for sintering, with the furnace temperature controlled at 1420-1460℃ and held for 2-3 hours. The shape and dimensions of the obtained sintered blank are shown in [reference needed]. Figure 2 As shown (the sintered blank has a ring-shaped structure with an inner diameter d=63.5mm, an inner diameter D=86.5mm, a total thickness H=15.2mm, and a working part thickness h=2.5mm); the surface of the sintered blank is ground to achieve the required dimensional accuracy and surface finish, resulting in the product, which is then inspected and put into storage.

[0065] The product prepared in this embodiment was sampled and the results are as follows: density is 7.2 g / cm³, hardness of working part is 90.2 HRA, bending strength (gradient alloy standard block, working part thickness 1.5 mm) is 1450 MPa, porosity of working part is AO2BO4CO0, and dimensional tolerances meet the requirements.

[0066] Example 2

[0067] This embodiment provides a lightweight gradient cemented carbide, comprising working and non-working parts sintered together with different compositions.

[0068] The working part is made of a cermet-ceramic cemented carbide material, which is composed of the following components by weight percentage: 40% titanium carbide, 20% tungsten carbide, 15% tantalum carbide or niobium carbide, 5% molybdenum carbide, and 20% nickel; the density value of the working part is calculated using the following formula:

[0069] ρ1 = 1 / (Percentage of titanium carbide / density of titanium carbide + percentage of tungsten carbide / density of tungsten carbide + percentage of tantalum carbide or niobium carbide / density of tantalum carbide or niobium carbide + percentage of molybdenum carbide / density of molybdenum carbide + percentage of nickel / density of nickel).

[0070] Of which, titanium carbonitride (TiCN) accounts for 40%, and the density of titanium carbonitride (TiCN) is 5.08 g / cm³;

[0071] The percentage of tungsten carbide (WC) is 20%, and the density of tungsten carbide (WC) is 15.7 g / cm³.

[0072] The percentage of tantalum carbide or niobium carbide (Ta(Nb)C) is 15%, and the density of tantalum carbide or niobium carbide (Ta(Nb)C) is 14.3 g / cm³.

[0073] The percentage of molybdenum carbide (Mo2C) is 5%, and the density of molybdenum carbide (Mo2C) is 9.18 g / cm³.

[0074] The percentage of nickel (Ni) is 20%, and the density of nickel (Ni) is 8.9 g / cm³.

[0075] Therefore, ρ1 = 1 / (0.4 / 5.08 + 0.2 / 15.7 + 0.15 / 14.3 + 0.05 / 9.18 + 0.2 / 8.9) = 7.7 g / cm³ ³

[0076] The non-working part is made of lightweight cemented carbide material, which is composed of the following components by weight percentage: 40% titanium carbide powder, 45% tungsten carbide powder, and 15% nickel powder. The density of the non-working part is denoted as ρ², and the formula for calculating the density value of the non-working part is:

[0077] ρ2 = 1 / (Percentage of titanium carbide powder / Density of titanium carbide powder + Percentage of tungsten carbide powder / Density of tungsten carbide powder + Percentage of nickel powder / Density of nickel powder)

[0078] The titanium carbide powder (TiC powder) accounts for 40% of the total content, and the density of the titanium carbide powder (TiC powder) is 4.93 g / cm³.

[0079] The percentage of tungsten carbide powder (waste WC-Co powder) is 45%, and the density of tungsten carbide powder (waste WC-Co powder) is 14.1 g / cm³;

[0080] The percentage of nickel powder or cobalt powder (Ni powder or Co powder) is 15%, and the density of nickel powder or cobalt powder (Ni powder or Co powder) is 8.9 g / cm³.

[0081] ρ2=1 / (0.4 / 4.93+0.45 / 14.1+0.15 / 8.9)=7.7g / cm³.

[0082] The preparation method of this lightweight gradient cemented carbide is as follows: Weigh and mix the above-mentioned components according to the weight ratio; load the working part and non-working part mixtures into different ball mills for wet grinding, with a ball-to-material ratio of 4:1 and a solid-liquid ratio of 1 kg / 300 ml, and ball mill at room temperature for 24 hours; after ball milling, use a vacuum dryer (Z-type mixer) to recover alcohol from the wet-ground materials of the working part and non-working part, and then dry them in a steam drying oven; add SD adhesive liquid (or gasoline rubber liquid) molding agent to the dried powder and stir evenly (2 minutes); add 100-110 ml / kg of adhesive to the working part powder and 120 ml / kg of adhesive to the non-working part powder, and sieve through a 60-100 mesh screen; first weigh 2 g of working part powder, put it into a steel mold and level it, then weigh 3.25 g of non-working part powder, add it into the steel mold and level it, and press it into shape under pressure of 60-100 MPa / cm². The shape of the pressed blank is as follows. Figure 3 As shown (the pressed billet has a strip-shaped structure with a total thickness of H=6.56mm); the pressed billet is then placed in a vacuum furnace for sintering, with the furnace temperature controlled at 1420-1460℃ and held for 2-3 hours. The shape and dimensions of the obtained sintered billet are shown in [reference needed]. Figure 4 As shown (the sintered blank is a strip structure with a total thickness of H=2.25mm); the surface of the sintered blank is trimmed to ensure that the dimensions and surface meet the requirements, and the product is obtained. After passing the inspection, it is put into storage.

[0083] The product prepared in this embodiment was sampled and the results are as follows: density 7.7 g / cm³, hardness of working part 91.2 HRA, bending strength (gradient alloy standard block, working part thickness 2.5 mm) 1260 MPa, porosity of working part AO2BO2CO0, and sintered billet size meets the requirements.

[0084] Comparative Example

[0085] Using CN102434665A, a patent entitled "A Lightweight Gradient Hard Alloy Sealing Ring and Its Manufacturing Method," as a comparative example, this patent discloses the following: A lightweight gradient hard alloy sealing ring and its manufacturing method, wherein the sealing ring consists of a working part and a non-working part; the working part is composed of 90-94% by weight tungsten carbide and 6-10% by weight nickel or cobalt, with a layer thickness of 1.0-2.5 mm; the non-working part is composed of 40-60% by weight titanium carbide powder, 10-18% by weight nickel powder, and 22-50% by weight tungsten carbide powder; during pressing, the hard alloy material for the working part is first weighed, added to a steel mold and leveled, then the lightweight hard alloy material for the non-working part is weighed, added to a steel mold and leveled, pressure is applied and pressed into shape, and then placed in a furnace for sintering to obtain a gradient hard alloy sealing ring with two different compositions.

[0086] The density difference between the working and non-working parts of this invention is too large, and the density cannot be made consistent by adjusting the formula. This results in a large difference in the shrinkage ratio of the finished product after sintering, making it difficult to obtain a stable and definite size of the finished product and preventing large-scale production. This limits the scope of application of the invention to the preparation of products such as sealing rings.

Claims

1. A lightweight gradient cemented carbide, characterized in that, It includes working and non-working parts with different compositions but the same density. The working part is a cermet cemented carbide material, which is composed of the following components by weight percentage: 35%-45% titanium carbide, 10%-20% tungsten carbide, 15% tantalum carbide or niobium carbide, 5% molybdenum carbide, and 15%-25% nickel. The non-working part is made of lightweight cemented carbide material, which is composed of the following components by weight percentage: 40%-60% titanium carbide powder, 22%-50% tungsten carbide powder, and 15%-18% nickel powder or cobalt powder.

2. The lightweight gradient cemented carbide according to claim 1, characterized in that, The thickness of the working part is 1-2.5mm.

3. The lightweight gradient cemented carbide according to claim 1, characterized in that, The working part is a cermet cemented carbide material, which is composed of the following components by weight percentage: 45% titanium carbide, 10% tungsten carbide, 15% tantalum carbide or niobium carbide, 5% molybdenum carbide, and 25% nickel; The non-working part is made of lightweight cemented carbide material, which is composed of the following components by weight percentage: 46% titanium carbide powder, 36% tungsten carbide powder, and 18% nickel or cobalt powder.

4. The lightweight gradient cemented carbide according to claim 1, characterized in that, The working part is a cermet cemented carbide material, which is composed of the following components by weight percentage: 40% titanium carbide, 20% tungsten carbide, 15% tantalum carbide or niobium carbide, 5% molybdenum carbide, and 20% nickel; The non-working part is made of lightweight cemented carbide material, which is composed of the following components by weight percentage: 40% titanium carbide powder, 45% tungsten carbide powder, and 15% nickel or cobalt powder.

5. A lightweight gradient cemented carbide according to claim 1, characterized in that, The working part and the non-working part are connected into one piece by sintering.

6. The lightweight gradient cemented carbide according to claim 1, characterized in that, The tungsten carbide in the non-working parts is electrolytic tungsten carbide powder recycled from waste cemented carbide or crushed waste cemented carbide powder.

7. A method for manufacturing a lightweight gradient cemented carbide, using a lightweight gradient cemented carbide according to any one of claims 1 to 5, comprising the following steps: S1. Prepare the metal-ceramic hard alloy mixture for the working part, and calculate the density value of the working part based on the percentage content of each component in the formula and the density of its components. S2. Prepare a lightweight hard alloy mixture for the non-working part. Calculate the density value of the non-working part based on the percentage content and density of each component in the non-working part formula. Adjust the percentage of each component in the non-working part appropriately based on the density value of the working part in step S1, and finally make the density of the working part consistent with the density value of the non-working part. S3. Compression molding of working and non-working parts: S31. Since the density of the metal-ceramic hard alloy mixture in the working part and the light hard alloy mixture in the non-working part are the same, their shrinkage coefficients are also the same. There is no need to change the shape of the pressed blank. It is only necessary to design the shape of the pressed blank to be consistent with the shape of the sintered blank. S32. First, weigh and add the metal-ceramic hard alloy mixture obtained in step S1 to the working part in the steel mold, and level it; then weigh and add the lightweight hard alloy mixture obtained in step S2 to the non-working part, and level it; apply 60-100MPa / cm² to the steel mold for pressing and molding to obtain the processed pressed product. S4. The pressed products obtained in step S32 are sintered and put into storage after passing inspection.

8. The method for manufacturing a lightweight gradient cemented carbide according to claim 7, characterized in that, Step S1 includes the following specific steps: S11. The working part is weighed with the following components by weight percentage: 35%-45% titanium carbide, 10%-20% tungsten carbide, 15% tantalum carbide or niobium carbide, 5% molybdenum carbide and 15%-25% nickel, and then the above components are mixed evenly to obtain a mixture. S12. Place the mixture obtained in step S11 into a ball mill for wet milling, wherein the ball-to-material ratio is 4:1 and the solid-to-liquid ratio is 1kg / 300ml. Mill at room temperature for 24 hours to obtain wet material. S13. After recovering the alcohol from the ground wet material obtained in step S12 using a vacuum dryer, the material is then dried in a steam drying oven to obtain dry powder. S14. Add SD adhesive or gasoline rubber liquid molding agent to the dry powder obtained in step S13 and stir evenly for 2 minutes. The amount of adhesive added is 100-110 ml / kg. Sieve through a 60-100 mesh sieve to obtain the metal-ceramic hard alloy mixture for the working part.

9. The method for manufacturing a lightweight gradient cemented carbide according to claim 7, characterized in that, Step S2 includes the following specific steps: S21. The non-working part is composed of the following components by weight percentage: 40%-60% titanium carbide powder, 22%-50% tungsten carbide powder, and 15%-18% nickel or cobalt powder. The density value of the non-working part is calculated by taking values ​​within this range. The component percentages of the non-working part are adjusted to make the density values ​​of the working part and the non-working part consistent. The adjusted weight percentages of the components of the non-working part are then uniformly mixed to obtain a mixture. S22. Place the mixture obtained in step S21 into a ball mill for wet milling. The ball-to-material ratio is 4:1 and the solid-liquid ratio is 1kg / 300ml. Mill at room temperature for 24 hours to obtain wet material. S23. After recovering the alcohol from the ground wet material obtained in step S22 using a vacuum dryer, it is then dried in a steam drying oven to obtain dry powder. S24. Add SD adhesive or gasoline rubber liquid molding agent to the dry powder obtained in step S23 and stir evenly for 2 minutes. The amount of adhesive added is 120 ml / kg. Sieve through a 60-100 mesh sieve to obtain the lightweight hard alloy mixture for the non-working part.

10. The method for manufacturing a lightweight gradient cemented carbide according to claim 7, characterized in that, Step S4 includes the following specific steps: S41. Add the pressed product obtained in step S32 into a vacuum furnace for sintering. The temperature inside the vacuum furnace is controlled at 1420-1500℃ and held for 2-3 hours to obtain the sintered product. S42. Grind the surface of the product obtained in step S41 according to the dimensional accuracy requirements, and put it into storage after passing the inspection.

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