A tool material for deep hole machining of hard metal and a method for producing the same

Abstract

The application discloses a kind of hard alloy cutter materials for deep hole machining, the cutter material is composed of the following weight percentage components: tungsten carbide: 75%~85%, wherein 0.2~0.4 μm superfine tungsten carbide particles account for 60%~80%, 0.4~0.8 μm tungsten carbide particles account for 20%~40%; Cobalt: 10%~15% titanium carbide: 2%~5%; Tantalum carbide: 1%~3%; Niobium carbide: 0.5%~2%; Vanadium carbide: 0.3%~1.0%; Chromium carbide: 0.2%~0.8%; Rare earth element: Y2O3 Or La2O3: 0.1%~0.5%. The application breaks through the bottleneck of high temperature wear, insufficient strength and short service life of traditional hard alloy in deep hole machining through three-dimensional innovation of component design, structure control and surface strengthening, and provides an efficient solution for precision deep hole machining of high hardness materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tool materials, in particular to a cemented carbide tool material for deep hole machining and a preparation method thereof. BACKGROUND

[0002] Deep hole machining is a key technology in the field of mechanical manufacturing, and is widely used in the machining of precision parts such as aerospace engine housings, nuclear power steam generator tube plates, and automobile hydraulic valve bodies. The typical machining characteristics are a length-diameter ratio ≥ 20 and a material hardness ≥ HRC30 (such as nickel-based superalloy, titanium alloy, and other difficult-to-machine materials). In such machining scenarios, the tool must withstand extremely high cutting pressure (1000-3000 MPa), friction heat (local temperature up to 800-1000℃), and alternating stress, which puts stringent requirements on the hardness, wear resistance, high-temperature stability, and fatigue resistance of the tool material.

[0003] Traditional deep hole machining tools mostly use WC-Co-based cemented carbide, but the existing technology has the following defects:

[0004] Component design limitations: Single tungsten carbide particle size distribution leads to insufficient microstructure uniformity, and stress concentration is easily formed at the grain boundaries; although TiC, TaC, and other carbides are commonly added to improve high-temperature hardness, they lack a synergistic inhibition mechanism for WC grain growth, resulting in weak grain boundary strength (such as the limited grain refinement effect of traditional VC or Cr3C2 single inhibitors, with an average grain size ≥ 1μm); the cobalt binder phase is prone to softening and carbide dissolution at high temperatures, leading to binder failure (such as a more than 40% decrease in the bending strength of traditional WC-10Co alloy at 800℃).

[0005] Preparation process defects: Ordinary ball milling process cannot achieve uniform dispersion of nanoscale carbide powder, and agglomerates are easily formed (such as a span ≥ 1.5 for mixed powder in traditional processes); atmospheric sintering leads to residual micro-pores in the material (porosity ≥ 0.5%), and the cobalt binder phase is unevenly distributed (content standard deviation ≥ 3%), significantly reducing fatigue resistance; the surface treatment precision is insufficient (Ra ≥ 0.8μm), and built-up edges are easily generated during cutting, exacerbating tool wear.

[0006] Performance bottlenecks: Existing tools have a wear rate ≥ 1×10 -5 mm 3 / (N·m) when machining nickel-based alloys, with a tool life of only 30-50 minutes, which cannot meet the efficiency and precision requirements of high-precision deep hole machining; the high-temperature oxidation resistance temperature is ≤ 850℃, and oxidation wear and coating peeling are easily generated during the machining process.

[0007] Therefore, there is an urgent need to develop a cemented carbide tool material with ultra-fine grain structure, multi-element synergistic strengthening, and dense and uniform organization, to break through the existing technical bottlenecks through component optimization and process innovation. SUMMARY

[0008] The present application aims to provide a cemented carbide tool material for deep hole machining and a preparation method thereof to solve the problems presented in the background.

[0009] To achieve the above-mentioned purpose, the present application provides the following technical solution: a cemented carbide tool material for deep hole machining, the tool material is composed of the following components by weight percentage:

[0010] Tungsten carbide (WC): 75% to 85%, wherein 0.2-0.4 μm ultra-fine tungsten carbide particles account for 60%-80%, 0.4-0.8 μm tungsten carbide particles account for 20%-40%;

[0011] Cobalt (Co): 10% to 15%;

[0012] Titanium carbide (TiC): 2% to 5%;

[0013] Tantalum carbide (TaC): 1% to 3%;

[0014] Niobium carbide (NbC): 0.5% to 2%;

[0015] Vanadium carbide (VC): 0.3% to 1.0%;

[0016] Chromium carbide (Cr3C2): 0.2% to 0.8%;

[0017] Rare earth elements (Y2O3 or La2O3): 0.1% to 0.5%.

[0018] Preferably, the tungsten carbide particles form a bimodal particle size distribution structure, 0.2-0.4 μm particles fill the gap between 0.4-0.8 μm particles, the rare earth element-rich phase at the grain boundary accounts for ≤5% and is uniformly distributed in the cobalt binder phase.

[0019] Preferably, the cobalt binder phase forms a three-dimensional interconnected network structure, the average free path thereof is 0.5-1.2 μm by image analysis, and (Ti, Ta, Nb, Cr) carbide nanoparticles with a size ≤100 nm are distributed at the network nodes.

[0020] Preferably, the composite carbide phase is composed of (W, Ti, Ta, Nb, Cr, V) C solid solution, the lattice distortion rate thereof is ≥0.8% by X-ray diffraction detection, and VC and Cr3C2 at the grain boundary form a gradient solid solution layer with a thickness of 50-200 nm.

[0021] A preparation method of a cemented carbide tool material, comprising the following steps:

[0022] (1) According to the proportion, the bimodal particle size tungsten carbide powder, cobalt powder and multi-component carbide powder are weighed and added with 0.1% to 0.5% of rare earth oxides in total mass of the raw materials;

[0023] (2) In inert gas protection, the planetary ball mill is used for grading ball milling: first, the agglomerates are broken by high-speed ball milling at 800 to 1000 rpm for 4 to 6 hours, and then the particle size is balanced by low-speed ball milling at 300 to 500 rpm for 8 to 10 hours, the ball milling medium is WC-Co alloy ball with a diameter of 3 to 5 mm, and the ball-to-material ratio is 10:1 to 15:1;

[0024] (3) During the ball milling process, 1% to 2% of polyethylene glycol and 0.5% to 1% of oleic acid composite binder are added in total mass of the powder, and after ball milling, the slurry is treated by vacuum freeze drying, the drying temperature is -50 to -30℃, the vacuum degree is ≤10Pa, and the drying time is 24 to 36 hours;

[0025] (4) Two-way cold isostatic pressing is used for forming, first pre-pressing at 50 to 100 MPa for 5 to 10 minutes, and then pressure holding at 150 to 200 MPa for 15 to 20 minutes, the forming pressure is dynamically controlled by a hydraulic servo system, and the pressure fluctuation is ≤±2%;

[0026] (5) The sintering process is divided into three stages: the first stage is degreasing treatment at 500 to 800℃, the heating rate is 5 to 10℃ / min, and the holding time is 1 to 2 hours; the second stage is vacuum sintering at 1380 to 1420℃, the vacuum degree is ≤10-3Pa, the holding time is 1.5 to 2 hours, and high-purity argon gas with a flow rate of 5 to 10 L / min is introduced during the process; the third stage is simultaneously subjected to hot isostatic pressing treatment, the treatment temperature is 1350 to 1400℃, the pressure is 100 to 150 MPa, and a gradient cooling process is adopted, and the cooling rate is 10 to 15℃ / min.

[0027] Preferably, 0.05% to 0.1% of nano-diamond particles in total mass of the raw materials are added as a dispersing aid in the ball milling process, the mixed powder D50 is ≤0.6μm, and the span is ≤1.2, detected by a laser particle size analyzer.

[0028] Preferably, the surface treatment process after sintering includes: first, ultrasonic vibration polishing is performed, the polishing liquid is deionized water solution containing 5% to 10% Al2O3 abrasive, the frequency is 20 to 40 kHz, and the treatment time is 30 to 60 minutes; then, a TiAlN-based nano-composite coating with a thickness of 2 to 5μm is prepared by physical vapor deposition (PVD), the coating surface roughness Ra is ≤0.2μm, and the microhardness is ≥3000HV.

[0029] Preferably, the microstructure of the tool material satisfies: cobalt binder phase content distribution standard deviation ≤1.5%, carbide grain size variation coefficient ≤15%, porosity observed by scanning electron microscope ≤0.1%, and no defective pores greater than 5μm.

[0030] Preferably, the high-temperature performance parameters of the tool material are: 800℃ high-temperature hardness ≥HRA88, oxidation resistance temperature ≥900℃, and wear rate ≤5×10 -6 mm 3 / (N·m) after a disc wear test.

[0031] Preferably, when the tool material is used for deep hole machining, the tool life is improved by more than 30% compared with traditional WC-Co hard alloy in the deep hole scenario with a machining diameter of 5-50mm and a length-diameter ratio ≥20, and the machining surface roughness Ra is ≤0.4μm.

[0032] The tool material for deep hole machining and the preparation method thereof have the beneficial effects that:

[0033] 1. Multi-element synergistic strengthening component system: bimodal particle size tungsten carbide skeleton: 0.2-0.4μm ultra-fine particles fill in the gap between 0.4-0.8μm particles, forming a composite structure of "coarse crystal support-fine crystal strengthening", which makes the material hardness (HRA92-94) increase by 3-5% compared with traditional single particle size alloy, and the fracture toughness (KIC≥12MPa·m 1 / 2 ) increases by 15%, effectively inhibiting crack propagation.

[0034] 2. Rare earth element modification: Y2O3 or La2O3 forms a nanoscale rare earth enrichment phase (accounting for ≤5%) at the grain boundary, hinders dislocation movement through lattice distortion effect (lattice distortion rate ≥0.8%), and inhibits abnormal growth of WC grains (average grain size ≤0.6μm), which makes the high-temperature hardness (800℃≥HRA88) increase by 8-10% compared with traditional alloy.

[0035] 3. Gradient grain boundary strengthening: VC and Cr3C2 form a solid solution layer with a thickness of 50-200nm at the grain boundary, combined with the dispersion distribution of (Ti, Ta, Nb, Cr) carbide nanoparticles (≤100nm) in the cobalt binder phase, which significantly improves the grain boundary bonding strength, making the bending strength (2500-3000MPa) increase by 20-30% compared with traditional alloy.

[0036] 4. Hierarchical ball milling and composite binder: high-speed crushing agglomerates + low-speed particle size balancing process, combined with PEG and oleic acid composite binder, makes the mixed powder D50 ≤0.6μm, span ≤1.2, and nanodiamond dispersion aids further inhibit carbide particle agglomeration, laying a foundation for uniform microstructure.

[0037] 5. Gradient sintering and HIP treatment: three-stage process of vacuum debinding-high temperature sintering-hot isostatic pressing, eliminating micro-pores (porosity ≤0.1%) and forming a three-dimensional interconnected network of cobalt binder phase (average free path 0.5-1.2 μm, content standard deviation ≤1.5%), material density ≥99.9%, fatigue resistance increased by more than 40%.

[0038] 6. Nano-composite coating treatment: TiAlN-based coating (hardness ≥3000 HV) combined with ultra-fine polishing (Ra≤0.2 μm), reducing cutting friction coefficient (25% lower than traditional surface), reducing built-up edge formation, tool wear rate ≤5×10 - 6 mm 3 / (N·m), life increased by more than 30% compared to traditional alloys.

[0039] 7. Directional performance design: for high aspect ratio scenarios of deep hole machining, high temperature oxidation resistance of material ≥900℃, machining surface roughness Ra≤0.4 μm, meeting the dual needs of deep hole machining precision (roundness error ≤0.02 mm) and efficiency in nuclear power, aviation and other fields.

[0040] In summary, through three-dimensional innovation of component design, microstructure regulation and surface strengthening, the application breaks through the bottlenecks of high temperature wear, insufficient strength and short life of traditional cemented carbide in deep hole machining, and provides an efficient solution for precision deep hole machining of high hardness materials. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0042] Example 1: standard deep hole machining tool material;

[0043] Raw material ratio (weight percentage):

[0044] Tungsten carbide (WC): 80% (of which 0.2-0.4 μm ultra-fine particles account for 70%, 0.4-0.8 μm particles account for 30%);

[0045] Cobalt (Co): 12.5%;

[0046] Titanium carbide (TiC): 3.5%;

[0047] Tantalum carbide (TaC): 2%;

[0048] Niobium carbide (NbC): 1%;

[0049] Vanadium carbide (VC): 0.6%;

[0050] Chromium carbide (Cr3C2): 0.5%;

[0051] Rare earth element (Y2O3): 0.3%.

[0052] A preparation method of a cemented carbide tool material, the specific steps are as follows:

[0053] Batching and mixing:

[0054] The bimodal particle size WC powder (D50 is 0.3 μm and 0.6 μm respectively), Co powder (purity ≥ 99.9%, particle size ≤ 5 μm) and each carbide powder are weighed according to the proportion, and 0.3% of Y2O3 powder of the total mass of raw materials is added;

[0055] Under the protection of argon, a planetary ball mill is used for grading ball milling: first, high-speed ball milling at 900 rpm for 5 hours to break up the agglomerates, and then low-speed ball milling at 400 rpm for 9 hours to balance the particle size, the ball milling medium is WC-Co alloy ball (hardness HRA89) with a diameter of 4 mm, and the ball-to-material ratio is 12:1;

[0056] During the ball milling process, 1.5% PEG-400 and 0.8% oleic acid composite binder are added to form a uniform slurry.

[0057] Drying and forming:

[0058] The slurry is transferred to a vacuum freeze dryer, dried at -40℃ and a vacuum degree of 5 Pa for 30 hours, and a pre-prepared powder with good fluidity is obtained (laser particle size detection D50=0.55 μm, span=1.1);

[0059] Two-way cold isostatic pressing is adopted: first, pre-pressing at 80 MPa for 8 minutes, and then pressure holding at 180 MPa for 18 minutes (pressure fluctuation ±1.5%), to obtain a cylindrical green compact (diameter 20 mm, height 50 mm) with uniform density.

[0060] Sintering and post-treatment:

[0061] Debinding stage: heating from 500℃ to 800℃ at a rate of 8℃ / min, and holding for 1.5 hours to remove the binder;

[0062] Vacuum sintering: 1390℃ for 1.8 hours, vacuum degree 10 -4 Pa, and 8L / min high-purity argon is introduced to inhibit oxidation;

[0063] Hot isostatic pressing (HIP): 1370℃, 120MPa for 3 hours, gradient cooling rate 12℃ / min, eliminate micro-porosity;

[0064] Surface treatment: ultrasonic vibration polishing (30kHz, 45min, polishing solution contains 8% Al2O3 abrasive), then deposit 3μm thickness TiAlN coating (surface roughness Ra=0.18μm, microhardness 3200HV).

[0065] Performance test:

[0066] Microstructure: scanning electron microscope observation shows that cobalt binder phase presents continuous network structure (average free path 0.8μm), Y2O3-rich phase at grain boundary accounts for 4.2%, porosity 0.08%.

[0067] Mechanical properties: hardness HRA 93.5, bending strength 2850MPa, high temperature hardness HRA 89.2 at 800℃, wear rate 4.8×10 -6 mm 3 / (N·m).

[0068] Machining test: 42CrMo deep hole with diameter 20mm and length-diameter ratio 30, tool life 75min, surface roughness Ra=0.35μm.

[0069] Example 2: high toughness type tool material (low WC content);

[0070] Raw material ratio (weight percentage):

[0071] Tungsten carbide (WC): 75% (of which 0.2-0.4μm ultra-fine particles account for 60%, 0.4-0.8μm particles account for 40%);

[0072] Cobalt (Co): 15%;

[0073] Titanium carbide (TiC): 2%;

[0074] Tantalum carbide (TaC): 3%;

[0075] Niobium carbide (NbC): 0.5%;

[0076] Vanadium carbide (VC): 1.0%;

[0077] Chromium carbide (Cr3C2): 0.8%;

[0078] Rare earth elements (La2O3): 0.1%.

[0079] A preparation method of a cemented carbide tool material, the specific steps are as follows:

[0080] Batching and mixing:

[0081] Double peak WC powder (D50 = 0.25 pm and 0.7 pm, ratio 6:4) was used, Co powder content was increased to 15% to enhance toughness, 0.1% La203was added;

[0082] Fractionated ball milling: high speed ball milling for 6 hours (1000 rpm) + low speed ball milling for 8 hours (300 rpm), ball to powder ratio 15:1, binder 2% PEG-400 and 1% oleic acid;

[0083] Drying and forming:

[0084] Vacuum freeze drying conditions: -50°C, 8 Pa, 36 hours, powder D50 = 0.6 pm, span = 1.2;

[0085] Cold isostatic pressing: pre-pressing 50 MPa x 10 min, final pressing 200 MPa x 15 min (pressure fluctuation ± 2%);

[0086] Sintering and post-treatment:

[0087] Debinding stage heating rate 5°C / min, holding time 2 hours; sintering temperature 1400°C, HIP treatment 1350°C, 100 MPa x 4 hours;

[0088] Surface treatment: coating was omitted, only ultrasonic polishing (Ra = 0.2 pm), original cemented carbide surface was preserved.

[0089] Performance test:

[0090] Microstructure: standard deviation of cobalt binder phase content 1.2%, coefficient of variation of carbide grain 12%, porosity 0.09%;

[0091] Mechanical properties: hardness HRA 92.8, bending strength 3000 MPa (toughness is outstanding), high temperature hardness HRA 88.5 at 800°C, fracture toughness KIC = 13 MPa.m 1 / 2 ;

[0092] Machining test: machining titanium alloy TC4 deep hole (aspect ratio 25), impact resistance is excellent, tool life is increased by 40% compared with traditional alloy.

[0093] Example 3: Ultra-high hardness tool material (high WC content + nano-diamond additive);

[0094] Raw material ratio (weight percentage):

[0095] Tungsten carbide (WC): 85% (of which 0.2-0.4 pm ultra-fine particles account for 80%, 0.4-0.8 pm particles account for 20%);

[0096] Cobalt (Co): 10%;

[0097] Titanium carbide (TiC): 5%;

[0098] Tantalum carbide (TaC): 1%;

[0099] Niobium carbide (NbC): 2%;

[0100] Vanadium carbide (VC): 0.3%;

[0101] Chromium carbide (Cr3C2): 0.2%;

[0102] Rare earth elements (Y2O3): 0.5%;

[0103] Nano-diamond particles: 0.08% (dispersing aid).

[0104] A method for preparing a cemented carbide tool material, comprising the following steps:

[0105] Batching and mixing:

[0106] Ultrafine WC particles are increased to 80% (D50 = 0.3 pm), and 0.08% nano-diamond (particle size 50 nm) and 0.5% Y2O3 are added.

[0107] Fractionated ball milling: high-speed ball milling for 4 hours (800 rpm) + low-speed ball milling for 10 hours (500 rpm), ball-to-material ratio 10:1, binder 1% PEG-400 and 0.5% oleic acid.

[0108] Drying and forming:

[0109] Vacuum freeze-drying: -30°C, 10 Pa, 24 hours, powder D50 = 0.5 pm (nano-diamond uniformly dispersed);

[0110] Cold isostatic pressing: pre-pressing 100 MPa x 5 minutes, final pressing 150 MPa x 20 minutes, uniformity of green density improved;

[0111] Sintering and post-processing:

[0112] Sintering temperature 1380°C, HIP treatment 1400°C, 150 MPa x 2 hours, density up to 99.95%;

[0113] Surface treatment: ultrasonic polishing (20 kHz, 60 minutes) followed by deposition of a 5 pm thick TiAlN coating (Ra = 0.15 pm, microhardness 3500 HV).

[0114] Performance testing:

[0115] Microstructure: (W, Ti, Ta, Nb, Cr, V)C solid solution lattice distortion rate 1.0%, VC / Cr3C2 gradient layer thickness at grain boundary 150nm, no defect porosity;

[0116] Mechanical properties: hardness HRA94, bending strength 2500MPa, high temperature hardness HRA90 at 800℃, oxidation resistance temperature 950℃ (100℃ higher than traditional alloy);

[0117] Processing test: processing nickel-based alloy Inconel718 deep hole (length-diameter ratio 40), wear rate 4.5x10 -6 mm 3 / (N·m), tool life 85min, surface roughness Ra=0.3μm.

[0118] Example comparison and effect summary:

[0119]

[0120] The above examples verify that the present application realizes the synergistic improvement of the hard alloy tool material in hardness, toughness, high temperature performance and processing adaptability through the dual-peak particle size design, rare earth modification, staged ball milling and gradient sintering process, and meets the needs of different deep hole processing scenes.

[0121] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A cemented carbide tool material for deep hole machining, characterized in that, The tool material is composed of the following components by weight percentage: Tungsten carbide: 75%~85%, wherein 0.2~0.4 μm ultrafine tungsten carbide particles account for 60%-80%, 0.4~0.8 μm tungsten carbide particles account for 20%-40%; Cobalt: 10%~15%; Titanium carbide: 2%~5%; Tantalum carbide: 1%~3%; Niobium carbide: 0.5%~2%; Vanadium carbide: 0.3%~1.0%; Chromium carbide: 0.2%~0.8%; Rare earth elements: Y2O3 or La2O3: 0.1%~0.5%.

2. The cemented carbide tool material according to claim 1, characterized in that, The tungsten carbide particles form a bimodal particle size distribution structure, 0.2~0.4 μm particles fill in the gaps between 0.4~0.8 μm particles, and the rare earth element-rich phase accounts for ≤5% at the grain boundaries and is uniformly distributed in the cobalt binder phase, as observed by scanning electron microscopy.

3. The cemented carbide tool material according to claim 2, characterized in that The cobalt binder phase forms a three-dimensional interconnected network structure, and the average free path thereof is 0.5~1.2 μm, and the network nodes are distributed with carbide nanoparticles with a size of ≤100 nm, as analyzed by image analysis.

4. The cemented carbide tool material according to claim 3, characterized in that The composite carbide phase is composed of a C solid solution, and the lattice distortion rate thereof is ≥0.8%, and a gradient solid solution layer with a thickness of 50~200 nm is formed by VC and Cr3C2 at the grain boundaries, as detected by X-ray diffraction.

5. A production method for producing the cemented carbide tool material according to claim 4, characterized in that, The method comprises the following steps: (1) The bimodal particle size tungsten carbide powder, cobalt powder and multi-element carbide powder are weighed according to the proportion, and 0.1%~0.5% of rare earth oxides based on the total mass of the raw materials are synchronously added; (2) Under the protection of inert gas, a planetary ball mill is used for grading ball milling: first, high-speed ball milling at 800~1000 rpm for 4~6 hours to break up the agglomerates, and then low-speed ball milling at 300~500 rpm for 8~10 hours to achieve particle size balance, the ball milling medium is WC-Co alloy ball with a diameter of 3~5 mm, and the ball-to-material ratio is 10:1~15:1; (3) During the ball milling process, 1%~2% of polyethylene glycol and 0.5%~1% of oleic acid complex binder based on the total mass of the powder are added, and after ball milling, the slurry is treated by vacuum freeze drying, the drying temperature is -50~-30℃, the vacuum degree is ≤10 Pa, and the drying time is 24~36 hours; (4) Two-way cold isostatic pressing is used for forming, first pre-pressing at 50~100 MPa for 5~10 minutes, and then pressure holding at 150~200 MPa for 15~20 minutes, the forming pressure is dynamically controlled by a hydraulic servo system, and the pressure fluctuation is ≤±2%; (5) The sintering process is divided into three stages: the first stage is degreasing treatment at 500~800℃, the heating rate is 5~10℃ / min, and the holding time is 1~2 hours; the second stage is vacuum sintering at 1380~1420℃, the vacuum degree is ≤10-3 Pa, the holding time is 1.5~2 hours, and high-purity argon gas with a flow rate of 5~10 L / min is introduced during the process; the third stage is simultaneously subjected to hot isostatic pressing treatment, the treatment temperature is 1350~1400℃, the pressure is 100~150 MPa, and a gradient cooling process is adopted, the cooling rate is 10~15℃ / min.

6. A method of producing a cemented carbide tool material according to claim 5, characterized in that The ball milling process adds 0.05% to 0.1% of nano-diamond particles as dispersing aids, and the mixed powder D50 is less than or equal to 0.6 microns and the span is less than or equal to 1.

2.

7. A method of producing a cemented carbide tool material according to claim 6, characterized in that, The surface treatment process after sintering includes: firstly, ultrasonic vibration polishing is performed, the polishing liquid is a deionized water solution containing 5% to 10% Al2O3 abrasive, the frequency is 20 to 40 kHz, and the processing time is 30 to 60 minutes; then, a TiAlN-based nano-composite coating with a thickness of 2 to 5 microns is prepared by physical vapor deposition (PVD), the surface roughness of the coating is less than or equal to 0.2 microns, and the microhardness is greater than or equal to 3000 HV.

8. A method of producing a cemented carbide tool material according to claim 7, characterized in that, The microstructure of the tool material satisfies: the standard deviation of the cobalt binder phase content distribution is less than or equal to 1.5%, the coefficient of variation of carbide grain size is less than or equal to 15%, the porosity observed by scanning electron microscopy is less than or equal to 0.1%, and there is no defect porosity greater than 5 microns.

9. A method of producing a cemented carbide tool material according to claim 8, characterized in that, The high temperature performance parameters of the tool material are: 800℃ high temperature hardness≥HRA88, oxidation resistance temperature≥900℃, and wear rate≤5×10 -6 mm 3 / (N·m) after disc abrasion test.

10. A method of producing a cemented carbide tool material according to claim 9, characterized in that, When the tool material is used for deep hole machining, in the deep hole scene with a machining diameter of 5 to 50 mm and a length-diameter ratio greater than or equal to 20, the tool life is improved by more than 30% compared with traditional WC-Co cemented carbide, and the machining surface roughness Ra is less than or equal to 0.4 microns.

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