Hard alloy material, preparation method thereof and hard alloy cutter

Abstract

The invention discloses a hard alloy material, a preparation method of the hard alloy material and a hard alloy cutter. The hard alloy material comprises the following components in parts by weight: 0.6-3.0 parts of a binding phase, 0.06-0.3 part of high-temperature carbide and 96.70-99.34 parts of WC, the binding phase comprises Co and Ni, and the mass percentage of the Ni in the binding phase is 40.0-70.0%; the high-temperature carbide comprises Cr3C2 and / or ZrC. The hard alloy material is good in ammonia organic substance corrosion resistance, the problems that a cutting edge of a traditional hard alloy material product is prone to breakage, the service life is short, and the precision in the machining process is poor can be solved, and the cost can be effectively controlled.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloys, and particularly relates to a cemented carbide, a preparation method thereof, and a cemented carbide tool. Background Art

[0002] With the further transformation and upgrading of the country, China's composite board industry is shifting from winning by quantity to developing with quality. It has become the consensus of each end user to select new products that are environmentally friendly and highly reliable in the fields of electronics and building materials. More and more enterprises are actively producing new national standard high-grade composite boards. When producing some high-grade composite boards (such as plywood and copper clad laminates), in order to achieve low formaldehyde content, natural proteins and low-formaldehyde epoxy resins are used as organic adhesives, and the decomposition temperature of the glue is increased by 100-200 °C compared with the previous urea-formaldehyde resin glue. However, the ammonia products decomposed are more corrosive to cemented carbide than benzene and phenolic substances.

[0003] Therefore, for the new composite board materials made of such organic ammonia adhesives, the performance requirements for the cemented carbide materials are higher heat resistance and corrosion resistance. In an ammonia substance corrosion medium, the cutting edge of the tool made of the cemented carbide material for processing composite boards wears and cracks rapidly, and the rapidly worn cutting edge generates more heat in the cutting area, further shortening the tool life. At the same time, the high temperature generated during dry cutting also destroys the surface integrity of the workpiece. At present, it is very difficult for the tool manufacturers and downstream enterprises to be satisfied with the single processing life and wear conditions of ordinary cemented carbide tools during the processing of the new composite boards made of such organic adhesives. For example, the patents with publication numbers CN114250396A and CN111321334A are both specific applications of corrosion-resistant cemented carbide in the fields of wood-based panels and wood processing, specifically related to cemented carbide tool materials. The above patents use WC as the main material and contain a binder phase of Co and / or Ni. However, the cemented carbide in the above patents is not specifically designed for the corrosion of organic ammonia substances, resulting in low service life when such cemented carbide materials are applied to the new composite board materials made of such organic adhesives.

[0004] Therefore, in order to meet the requirements of reducing production costs, improving work efficiency, and meeting the requirements of the corrosion resistance of organic ammonia substances, it is urgent to develop a cemented carbide tool with significantly improved corrosion resistance and wear resistance for new national standard composite boards and its related preparation method. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology, and provide a cemented carbide material for processing composite plates (plywood, copper clad laminates) made of ammonia-based organic adhesives, which has good corrosion resistance to ammonia-based organic substances, a longer service life, and its preparation method and cemented carbide cutting tools. This cemented carbide material can effectively overcome the problems of easy chipping of the cutting edge, low service life, and poor machining accuracy of traditional cemented carbide products, and can effectively control costs.

[0006] To solve the above technical problems, the technical solution proposed by the present invention is: A cemented carbide material for processing composite plates made of ammonia-based organic adhesives, comprising the following components in parts by weight: the binder phase is 0.6 - 3.0 parts, the high-temperature carbide is 0.06 - 0.3 parts, and WC is 96.70 - 99.34 parts; the binder phase includes Co and Ni, and the mass percentage of Ni in the binder phase is 40.0 - 70.0%; the high-temperature carbide includes Cr3C2 and / or ZrC.

[0007] In the above cemented carbide material, preferably, it is composed of the following components in mass percentage: the binder phase is 0.6 - 3.0%, the high-temperature carbide is 0.06 - 0.3%, and the balance is WC.

[0008] In the above cemented carbide material, preferably, the Fischer particle size of the high-temperature carbide is 1.1 - 1.5 μm.

[0009] In the above cemented carbide material, preferably, the average grain size of the WC is ≤ 0.8 μm; more preferably, the grain size of the WC is 0.2 - 0.6 μm, and the carbon balance is 0 to +0.10%.

[0010] In the above cemented carbide material, preferably, Co is added in the form of Co powder, and the Fischer particle size of the Co powder is 0.4 - 1.2 μm; Ni is added in the form of Ni powder, and the Fischer particle size of the Ni powder is 1.1 - 1.4 μm.

[0011] In the above cemented carbide material, preferably, the Vickers hardness of the cemented carbide material is 2000 - 2450 HV10, the flexural strength is 2500 MPa - 4500 MPa, and the fracture toughness is 7.0 - 9.5 MPa·m 1 / 2 。

[0012] As a general technical concept, the present invention also provides a preparation method of the above cemented carbide material, comprising the following steps: (1) Mix the binder phase, WC powder and molding agent, carry out first-stage wet grinding, then add high-temperature carbide and carry out second-stage wet grinding to obtain a mixed slurry, and dry to obtain a mixed powder; (2) Compress and mold the mixture, and sinter it to obtain a cemented carbide sintered body; during sintering, maintain positive pressure sintering from the initial stage of liquid-phase sintering.

[0013] In the above preparation method, preferably, the molding agent includes one or both of polyethylene glycol and paraffin, and the addition amount of the molding agent is 1.5-3.5% of the total mass of the raw materials; wet grinding is carried out by ball milling, and the ball milling medium used for ball milling is alcohol, and the solid-liquid ratio of its addition amount is 150-450 ml / kg; the wet grinding time for the first stage is 5-10 h, and the total time for the first-stage wet grinding and the second-stage wet grinding is 20-50 h, and the ball-to-material ratio during ball milling is (5-10):1, and the rotation speed is 30-40 revolutions per minute.

[0014] In the above preparation method, preferably, the compression molding adopts a pressing process or one of the processes of pre-pressing, isostatic pressing and extrusion; sintering is carried out in an inert atmosphere, in which an inert gas is introduced starting from the temperature range of 1200-1300 °C, and the gas pressure is controlled to be 100-600 mbar, and then continue to heat up to the sintering temperature range of 1400-1480 °C, and the gas pressure is controlled to be 30-100 bar, and keep warm for 0.5-2.0 h; the inert gas includes one or more of nitrogen, argon and helium. According to the sintering requirements, the present invention controls different positive pressure environments respectively, which is beneficial to ensuring the corrosion resistance of the product to ammonia-containing organic substances.

[0015] As a general technical concept, the present invention also provides a cemented carbide tool prepared by using the above cemented carbide material.

[0016] The above raw materials in the present invention can be self-made or obtained by commercial purchase, and the present invention does not make special limitations on this.

[0017] The composition of the cemented carbide material designed for processing composite plates made of ammonia-containing organic binders in the present invention, its design idea and basis are as follows: The design of the cemented carbide material should fully consider the material and working conditions characteristics of the composite plate, and the key performance indicators mainly considered are wear resistance, corrosion resistance, fracture toughness and the microstructure morphology of the material.

[0018] For the processing of new composite plates, the decomposition products during the processing contain ammonia-containing products. And the ammonia-containing products have stronger corrosiveness to cemented carbide than benzene and phenolic substances. Therefore, while ensuring that the cemented carbide has sufficient wear resistance, targeted ammonia corrosion resistance should also be considered.

[0019] The material design of the novel composite plate mainly considers the selection of high-temperature carbides and the design of the composition content of the binder phase. The types of high-temperature carbides mainly include Cr3C2, VC, TaC, ZrC, etc. The high-temperature carbides mainly play the roles of inhibiting the WC grain size, strengthening the binder phase, and stabilizing the interface between the hard phase and the binder phase. In the present invention, the high-temperature carbides Cr3C2 and / or ZrC and their mixtures are preferably used as grain inhibitors, which can form a composite solid solution phase inside the binder phase during the sintering stage. According to the solid solution strengthening mechanism, the strength and toughness of the alloy system can be synergistically enhanced. And in order to ensure the composite solid solution effect in the present invention, considering the density difference between the high-temperature carbides (Cr3C2 density: 6.68 g / cm 3 , ZrC density: 6.59 g / cm 3 ) and WC (WC density: 15.9 g / cm 3 ), in the preparation process, it is clearly stated that WC and Co are ball-milled for a period of time and then the high-temperature carbides are added to avoid the phenomenon of material stratification, thus affecting the composite solid solution effect.

[0020] The binder phase is the basis for ensuring that the alloy has good toughness and corrosion resistance. The binder phase content applicable to the present invention is in the category of low-cobalt alloys, and the selected binder phase is a type of composite binder phase of Co and Ni. Generally, in WC-Co-(Ni) alloys for cemented carbide cutting tools, the weight percentage of Ni / (Ni + Co) does not exceed 30% as a convention. This is because under the conventional vacuum / pressure sintering method, the volatilization of Ni is serious. Once the weight percentage is higher than 30%, it will cause insufficient content of the binder phase elements, resulting in a decrease in the bonding effect of the WC hard phase and seriously weakening the material properties. However, based on the actual application situation, increasing the content of Ni can effectively improve the ammonia corrosion resistance of the tool material for composite plate processing. It is found in the experiment that applying a positive pressure environment in the initial stage of liquid-phase sintering can maximize the inhibition of the volatilization process of Ni elements, and the remaining Ni forms a Ni layer on the surface. At the same time, the solubility of Cr in Ni is greater than that in Co, which will further enhance the element solid solution strengthening effect of the inhibitor and improve the corrosion resistance and toughness of the cemented carbide. In the present invention, the weight percentage of Ni / (Ni + Co) is 40.0 - 70.0%, and the addition of high Ni is beneficial to further improving its ammonia corrosion resistance compared with conventional cemented carbides.

[0021] Compared with the prior art, the advantages of the present invention are as follows: 1. The cemented carbide material of the present invention uses a composite binder phase of Co and Ni. By reasonably designing the weight percentage of Ni / (Ni + Co) to be 40 - 70.0%, applying a positive pressure at the initial stage of the liquid phase can prevent Ni from volatilizing, so that it remains in the liquid phase, realizing the high-proportion addition design of the ammonia corrosion-resistant element Ni and ensuring the ammonia corrosion resistance of the cemented carbide material.

[0022] 2. By optimizing the types and ratios of high-temperature carbides, and adopting Cr3C2 and / or ZrC and their mixtures, which have better compatibility with the high-nickel binder phase, the strengthening effect of the high-temperature carbides is achieved, further improving the wear resistance and toughness of the cemented carbide.

[0023] 3. The wet milling process of the present invention is optimized, and the addition timing of the high-temperature carbide is optimized, that is, the high-temperature carbide is added after WC, Co, Ni and other substances are ball-milled for a certain time. This enables the high-temperature carbide to be better dispersed and combined with the binder phase in the mixed slurry, fully exerting its synergistic composite strengthening and solid solution effect.

[0024] 4. The Vickers hardness of the cemented carbide prepared by the present invention is 2000 - 2450 HV, the flexural strength is 2500 - 4500 MPa, and the fracture toughness is 7.0 - 9.5 MPa·m 1 / 2 , and the ammonia corrosion resistance is improved by 5.3 - 25% compared with the comparative example, and it is fully applicable to the processing applications in the fields of composite plates (plywood, copper-clad laminate) and other materials.

[0025] Therefore, on the basis of fully exploring and analyzing the physical and service properties of existing cemented carbide materials, the present invention highly and fully applies the theories related to cemented carbide design and corrosion, solves the problems of easy wear, easy chipping of the cutting edge, and cracks caused by the shedding of hard phases that usually occur in existing materials in an ammonia corrosion environment, and invents a new type of cemented carbide material with stable physical properties, controllable microstructure and defects, excellent processing performance, and better service life, which better meets the processing requirements of new composite plates and breaks the foreign technical barrier blockade in this regard. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 It is a scanning electron microscope photograph of the cemented carbide material prepared in Example 1 of the present invention.

[0028] Figure 2 It is a scanning electron microscope photograph of the cemented carbide material prepared in Example 2 of the present invention.

[0029] Figure 3 It is a scanning electron microscope photograph of the cemented carbide material prepared in Example 3 of the present invention.

[0030] Figure 4The binder phase composition analysis results of the cemented carbide material prepared in Example 3 of the present invention.

[0031] Figure 5 This is a cutting edge morphology diagram of a milling cutter made of ultrafine cemented carbide material in Example 3 of the present invention after milling plywood for 3 hours.

[0032] Figure 6 This is the edge morphology of the milling cutter made of cemented carbide material in comparative example 1 after milling plywood for 3 hours. DETAILED DESCRIPTION

[0033] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0034] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0035] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0036] Embodiment 1: This embodiment provides a corrosion-resistant cemented carbide and a preparation method thereof, the preparation method comprising the following steps: S1: Co powder with a Fischer particle size of 0.4μm and Ni powder with a Fischer particle size of 1.1μm were selected for batching. The weight percentage of (Co+Ni) powder was 0.8%, and the weight ratio of Ni in the Co+Ni binder phase was 40%, of which the content of Ni powder was 0.32%, the content of Co powder was 0.48%, and the content of high-temperature carbides was 0.08%. The weight percentage of Cr3C2 with a Fischer particle size of 1.5μm was 0.06%, the weight percentage of ZrC with a Fischer particle size of 1.5μm was 0.02%, and the Fischer particle size of WC powder was 0.6μm, and the content was 99.12%. The carbon balance was controlled to +0.01%, and polyethylene glycol was used as a molding agent (the amount of molding agent added was 3.5% of the total mass of the powder).

[0037] S2: Ball-mill Co powder, Ni powder, WC powder, molding agent and alcohol for 5 hours, then add Cr3C2 and ZrC powder and continue ball-milling for a total of 20 hours. The liquid-solid ratio is 150 ml / Kg, the ball-to-material ratio is 5:1, and the ball mill speed is 40 rpm. After wet grinding, spray dry to obtain a mixture.

[0038] S3: The obtained mixture is molded by molding, and then pressure sintered in a gas pressure sintering furnace. Inert gas argon is passed at a temperature of 1300°C, and the gas pressure is 600mbar. It is sintered at 1480°C (inert gas argon is passed, the gas pressure is 30bar, and the sintering holding time is 2h). After sintering, a cemented carbide material is obtained.

[0039] The hard alloy material obtained in Example 1 was used for physical property testing, and its Vickers hardness was 2450 HV10, the bending strength was 2800 MPa, and the fracture toughness was 7.5 MPa·m 1 / 2 , SEM images are shown in Figure 1 The corrosion resistance test was carried out in a 1.0 mol / L ammonia corrosion solution. After immersion at 25°C for 24 hours, the weight loss rate of Example 1 was 0.041 g / m 2 h, the weight loss rate of comparative example 1 is 0.055g / m 2 h. Under the same experimental conditions, the corrosion resistance of Example 1 is significantly improved compared with that of Comparative Example 1.

[0040] Embodiment 2: This embodiment provides a corrosion-resistant cemented carbide and a preparation method thereof, the preparation method comprising the following steps: S1: Co powder with a Fischer particle size of 0.8μm and Ni powder with a Fischer particle size of 1.4μm were selected for batching. The weight percentage of (Co+Ni) powder was 2.0%, and the weight ratio of Ni in the Co+Ni binder phase was 50%, of which the Ni powder content was 1.0%, the Co powder content was 1.0%, and the content of high-temperature carbides was 0.2%. The weight percentage of Cr3C2 with a Fischer particle size of 1.3μm was 0.05%, the weight percentage of ZrC with a Fischer particle size of 1.1μm was 0.15%, and the Fischer particle size of WC powder was 0.2μm, and the content was 97.8%. The carbon balance was controlled to +0.05%, and polyethylene glycol was used as a molding agent (the amount of molding agent added was 3.0% of the total mass of the powder).

[0041] S2: Ball-mill Co powder, Ni powder, WC powder, molding agent and alcohol for 8 hours, then add Cr3C2 and ZrC powder and continue ball-milling for a total of 28 hours. The liquid-solid ratio is 250 ml / Kg, the ball-to-material ratio is 10:1, and the ball mill speed is 30 rpm. After wet grinding, spray drying is performed to obtain a mixture.

[0042] S3: The obtained mixture is molded by molding, and then pressure sintered in a gas pressure sintering furnace. Inert gas argon is passed at a temperature of 1200°C, and the gas pressure is 100mbar. It is sintered at 1400°C (inert gas argon is passed, the gas pressure is 60bar, and the sintering holding time is 0.5h). After sintering, a cemented carbide material is obtained.

[0043] The cemented carbide material obtained in Example 2 was used for physical property tests. Its Vickers hardness was 2250 HV10, the transverse rupture strength was 4500 MPa, and the fracture toughness was 8.0 MPa·m 1 / 2 , and the scanning electron microscope image is as shown in Figure 2 . The corrosion resistance test was carried out in a 1.0 mol / L ammonia water corrosion solution. After soaking at 25 °C for 24 hours, the weight loss rate of Example 2 was 0.047 g / m 2 ·h. Under the same experimental conditions, the corrosion resistance of Example 2 was significantly improved compared with Comparative Example 1.

[0044] Example 3: This example provides a corrosion-resistant cemented carbide and its preparation method. The preparation method includes the following steps: S1: When formulating the ingredients, Co powder with a Fisher particle size of 1.2 μm, Ni powder with a Fisher particle size of 1.2 μm were selected. The weight percentage of (Co + Ni) powder was 3.0%, the weight ratio of Ni in the Co + Ni binder phase was 70%, among which the percentage content of Ni powder was 2.1%, the percentage content of Co powder was 0.9%, and the content of the high-temperature carbide was 0.3%. Among them, the weight percentage of Cr3C2 with a Fisher particle size of 1.1 μm was 0.15%, the weight percentage of ZrC with a Fisher particle size of 1.2 μm was 0.15%, the Fisher particle size of the WC powder was 0.5 μm, and the content was 96.7%. The carbon balance was controlled to be +0.10%, and polyethylene glycol was used as the molding agent (the addition amount of the molding agent was 2.5% of the total mass of the powder).

[0045] S2: The Co powder, Ni powder, WC powder, molding agent and alcohol were ball-milled for 10 h, and then the Cr3C2 and ZrC powders were added and ball-milled until the total time reached 50 h. Among them, the liquid-solid ratio was 400 ml / Kg, the ball-to-material ratio was 6:1, and the rotation speed of the ball mill was 35 revolutions per minute. After the wet milling was completed, spray drying was carried out to obtain a mixed material.

[0046] S3: After the obtained mixed material was molded by die pressing, pressure sintering was carried out in a gas pressure sintering furnace. Inert gas argon was introduced at a temperature of 1250 °C, and the gas pressure was 400 mbar. Sintering was carried out at 1430 °C (inert gas argon was introduced, the gas pressure was 100 bar, and the sintering holding time was 1.0 h). After sintering was completed, a cemented carbide material was obtained.

[0047] The cemented carbide material obtained in Example 3 was used for physical property tests. Its Vickers hardness was 2150 HV10, the transverse rupture strength was 3900 MPa, and the fracture toughness was 9.0 MPa·m 1 / 2 , and the scanning electron microscope image is as shown in Figure 3 , Figure 4The two elements Zr and Cr were detected in the binder phase components, indicating that during the sintering process, the two elements Zr and Cr dissolved into the binder phase matrix, playing a positive role in synergistic solid solution strengthening. The corrosion resistance test was carried out in a 1.0 mol / L ammonia corrosion solution. After immersion at 25°C for 24 hours, the weight loss rate of Example 3 was 0.049 g / m 2 ·h. Under the same experimental conditions, the corrosion resistance of Example 3 is significantly improved compared with that of Comparative Example 1. Then, the Φ6.0*30mm rods prepared in Example 3 and the hard alloy of Comparative Example 1 were processed into milling cutters for plywood testing. The edge morphology of Example 3 and Comparative Example 1 was observed after cutting for 3 hours. Figure 5 , Figure 6 As shown, it was observed that the cutting edge of Example 3 remained intact ( Figure 5 ), while the cutting edge of comparative example 1 showed obvious wear ( Figure 6 ).

[0048] Embodiment 4: This embodiment provides a corrosion-resistant cemented carbide and a preparation method thereof, the preparation method comprising the following steps: S1: Co powder with a Fischer particle size of 1.2μm and Ni powder with a Fischer particle size of 1.2μm were selected for batching. The weight percentage of (Co+Ni) powder was 3.0%, and the weight ratio of Ni in the Co+Ni binder phase was 40%, of which the Ni powder content was 1.2%, the Co powder content was 1.8%, and the content of high-temperature carbides was 0.3%. The weight percentage of Cr3C2 with a Fischer particle size of 1.1μm was 0.15%, the weight percentage of ZrC with a Fischer particle size of 1.2μm was 0.15%, and the Fischer particle size of WC powder was 0.5μm, and the content was 96.7%. The carbon balance was controlled to +0.10%, and polyethylene glycol was used as a molding agent (the amount of molding agent added was 2.5% of the total mass of the powder).

[0049] S2: Ball-mill Co powder, Ni powder, WC powder, molding agent and alcohol for 10 hours, then add Cr3C2 and ZrC powder and continue ball-milling for a total of 50 hours, with a liquid-solid ratio of 400 ml / Kg, a ball-to-material ratio of 6:1, and a ball mill speed of 35 rpm. After wet grinding, spray dry to obtain a mixture.

[0050] S3: The obtained mixture is molded by molding, and then pressure sintered in a gas pressure sintering furnace. Inert gas argon is passed at a temperature of 1250°C, and the gas pressure is 400mbar. It is sintered at 1430°C (inert gas argon is passed, the gas pressure is 100bar, and the sintering holding time is 1.0h). After sintering, a cemented carbide material is obtained.

[0051] The hard alloy material obtained in Example 4 was used for physical property testing, and its Vickers hardness was 2130HV10, bending strength was 3850MPa, and fracture toughness was 9.0MPa·m 1 / 2 The corrosion resistance test was carried out in a 1.0 mol / L ammonia corrosion solution. After immersion at 25°C for 24 hours, the weight loss rate of Example 4 was 0.050 g / m 2 Under the same experimental conditions, the corrosion resistance of Example 4 is significantly improved compared with that of Comparative Example 1.

[0052] Embodiment 5: This embodiment provides a corrosion-resistant cemented carbide and a preparation method thereof, the preparation method comprising the following steps: S1: Co powder with a Fischer particle size of 1.2μm and Ni powder with a Fischer particle size of 1.2μm are used for batching, the weight percentage of (Co+Ni) powder is 3.0%, the weight ratio of Ni in the Co+Ni binder phase is 40%, of which the Ni powder content is 1.2%, the Co powder content is 1.8%, the content of high-temperature carbides is 0.3%, of which the weight percentage of Cr3C2 with a Fischer particle size of 1.1μm is 0.3%, and the Fischer particle size of WC powder is 0.5μm, and the content is 96.7%. The carbon balance is controlled to +0.10%, and paraffin is used as a molding agent (the amount of molding agent added is 1.5% of the total mass of the powder).

[0053] S2: Ball-mill Co powder, Ni powder, WC powder, molding agent and alcohol for 10 hours, then add Cr3C2 and ZrC powder and continue ball-milling for a total of 50 hours, with a liquid-solid ratio of 400 ml / Kg, a ball-to-material ratio of 6:1, and a ball mill speed of 35 rpm. After wet grinding, spray dry to obtain a mixture.

[0054] S3: The obtained mixture is molded by molding, and then pressure sintered in a gas pressure sintering furnace. Inert gas argon is passed at a temperature of 1250°C, and the gas pressure is 400mbar. It is sintered at 1430°C (inert gas argon is passed, the gas pressure is 100bar, and the sintering holding time is 1.0h). After sintering, a cemented carbide material is obtained.

[0055] The hard alloy material obtained in Example 5 was used for physical property testing, and its Vickers hardness was 2140HV10, bending strength was 4000MPa, and fracture toughness was 9.3MPa·m 1 / 2 The corrosion resistance test was carried out in a 1.0 mol / L ammonia corrosion solution. After immersion at 25°C for 24 hours, the weight loss rate of Example 5 was 0.052 g / m 2·h. Under the same experimental conditions, the corrosion resistance of Example 5 is improved over that of Comparative Example 1. Then, the Φ3.0*40mm rods prepared in Example 5 and the cemented carbide of Comparative Example 1 were processed into drill bits for copper clad laminate processing tests, and the tool processing life after failure was measured. The tool failure occurred in Example 5 after 8h of processing, while the tool failure occurred in Comparative Example 1 after 6h of processing. Therefore, Example 5 shows better processing performance than Comparative Example 1.

[0056] Comparative Example 1: The comparative example is a high-end cemented carbide material from a foreign manufacturer used for composite material processing. Figure 5 The overall composition is 6.05% C, 0.26% Cr, 2.1% Co, 0.9% Ni and 90.68% W. The metallographic analysis shows that the grain size of WC in the alloy structure is 0.55μm. The performance of the cemented carbide sample of Comparative Example 1 is tested, and its Vickers hardness is 2150HV10, the bending strength is 2800MPa, and the fracture toughness is 7.5MPa·m 1 / 2 The corrosion resistance test was carried out in a 1.0 mol / L ammonia corrosion solution. After immersion at 25°C for 24 hours, the weight loss rate of the comparative example was 0.055 g / m 2 ·h. Tool test: First, the plywood was tested. The tool material model was Φ6.0*30mm bar. After milling for 3h, the tool edge wear was observed. Secondly, the copper clad laminate was tested. The tool material model was Φ3.0*40mm bar. The tool failure occurred in Example 1 after 6h of processing.

[0057] Comparative Example 2: This comparative example provides a corrosion-resistant cemented carbide and a preparation method thereof, the preparation method comprising the following steps: S1: Co powder with a Fischer particle size of 1.2μm and Ni powder with a Fischer particle size of 1.2μm were selected for batching. The weight percentage of (Co+Ni) powder was 3.0%, and the weight ratio of Ni in the Co+Ni binder phase was 70%, of which the content of Ni powder was 2.1%, the content of Co powder was 0.9%, and the content of high-temperature carbides was 0.3%. The weight percentage of Cr3C2 with a Fischer particle size of 1.1μm was 0.15%, the weight percentage of ZrC with a Fischer particle size of 1.2μm was 0.15%, and the Fischer particle size of WC powder was 0.5μm, and the content was 96.7%. The carbon balance was controlled to +0.10%, and polyethylene glycol was used as a molding agent (the amount of molding agent added was 2.5% of the total mass of the powder).

[0058] S2: Ball-mill Co powder, Ni powder, WC powder, a forming agent, and alcohol for 10 h, then add Cr3C2 and ZrC powders and continue ball-milling until the total time reaches 50 h. The liquid-solid ratio is 400 ml / Kg, the ball-to-material ratio is 6:1, and the rotational speed of the ball mill is 35 revolutions per minute. After wet milling, perform spray drying to obtain a mixed material.

[0059] S3: After the obtained mixed material is formed by die pressing, perform pressure sintering in a gas-pressure sintering furnace. Keep it under vacuum at a temperature of 1250 °C to 1429 °C without applying positive pressure, and sinter at 1430 °C (pass inert gas argon, the gas pressure is 100 bar, and the sintering holding time is 1.0 h). After sintering, a cemented carbide material is obtained.

[0060] The cemented carbide material obtained in Comparative Example 2 is used for physical property testing. Its Vickers hardness is 2110 HV10, the flexural strength is 3100 MPa, and the fracture toughness is 8.0 MPa·m 1 / 2 . The corrosion resistance test is carried out in a 1.0 mol / L ammonia water corrosion solution. After soaking at 25 °C for 24 hours, the weight loss rate of Comparative Example 2 is 0.053 g / m 2 ·h. Under the same experimental conditions, the corrosion resistance of Comparative Example 2 is improved compared with that of Comparative Example 1. However, in this comparative example, positive-pressure sintering was not used in the initial liquid phase, and the corrosion resistance will be worse than that of Example 3.

[0061] The microstructures of Examples 1 - 5 of the present invention are more uniform than that of Comparative Example 1, and the distribution of the binder phase is also more uniform. At the same time, when the hardness of the material in the examples reaches or exceeds that of Comparative Example 1, the fracture toughness is higher. This material design solves problems such as insufficient ammonia corrosion resistance in practical applications. At the same time, for the cemented carbide material of the present invention, Co + Ni is used as a composite binder phase, and positive pressure is introduced during the solid-liquid phase transition to control the volatilization of Ni, which can improve the stability of the ammonia corrosion-resistant element Ni. At the same time, high-temperature carbides such as Cr3C2 and ZrC play a solid-solution strengthening role, which is beneficial to improving the corrosion resistance and wear resistance of the material, thus improving the service life and stability of the cutting tool for composite material processing.

Claims

1. A cemented carbide material for processing composite boards made of ammonia-based organic adhesives, characterized in that, It comprises components in the following parts by weight: 0.6 - 3.0 parts of a binder phase, 0.06 - 0.3 parts of a high-temperature carbide, and 96.70 - 99.34 parts of WC; the binder phase includes Co and Ni, and the mass percentage of Ni in the binder phase is 40.0 - 70.0%; the high-temperature carbide includes Cr3C2 and / or ZrC.

2. The cemented carbide material according to claim 1, characterized in that, It is composed of components in the following mass percentages: 0.6 - 3.0% of a binder phase, 0.06 - 0.3% of a high-temperature carbide, and the balance is WC.

3. The cemented carbide material according to claim 1, characterized in that, The Fischer particle size of the high-temperature carbide is 1.1 - 1.5 μm.

4. The cemented carbide material according to claim 1, characterized in that, The grain size of the WC is 0.2 - 0.6 μm, and the carbon balance is 0 to +0.10%.

5. The cemented carbide material according to claim 1, characterized in that, Co is added in the form of Co powder, and the Fischer particle size of the Co powder is 0.4 - 1.2 μm; Ni is added in the form of Ni powder, and the Fischer particle size of the Ni powder is 1.1 - 1.4 μm.

6. The cemented carbide material according to claim 1, characterized in that, The Vickers hardness of the cemented carbide material is 2000 - 2450 HV10, the flexural strength is 2500 MPa - 4500 MPa, and the fracture toughness is 7.0 - 9.5 MPa·m 1 / 2 .

7. A method for preparing a cemented carbide material according to any one of claims 1-6, characterized in that, It includes the following steps: (1) Mix the binder phase, WC powder and a forming agent and conduct primary wet grinding, then add the high-temperature carbide and conduct secondary wet grinding to obtain a mixed slurry, and dry it to obtain a mixed powder; (2) Compress and mold the mixed material to obtain a cemented carbide sintered body; during sintering, maintain positive pressure sintering from the initial stage of liquid-phase sintering.

8. The preparation method according to claim 7, characterized in that, The forming agent includes one or both of polyethylene glycol and paraffin, and the addition amount of the forming agent is 1.5 - 3.5% of the total mass of the raw materials; wet grinding is carried out by ball milling, the ball milling medium used for ball milling is alcohol, and the solid-liquid ratio of its addition amount is 150 - 450 ml / kg; the primary wet grinding time is 5 - 10 h, the total time of primary wet grinding and secondary wet grinding is 20 - 50 h, the ball-to-material ratio during ball milling is (5 - 10):1, and the rotation speed is 30 - 40 revolutions per minute.

9. The preparation method according to claim 7, wherein Sintering is carried out in an inert atmosphere, wherein an inert gas is introduced starting from the temperature range of 1200 - 1300 °C, the gas pressure is controlled to be 100 - 600 mbar, continue to heat up to the sintering temperature range of 1400 - 1480 °C, control the gas pressure to be 30 - 100 bar, and keep warm for 0.5 - 2.0 h; the inert gas includes one or more of nitrogen, argon and helium.

10. A cemented carbide cutting tool, characterized in that, It is prepared by using the cemented carbide material described in any one of claims 1 - 6 or by using the preparation method described in any one of claims 7 - 9.

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