CN115572878A - Hard alloy material and preparation method and application thereof - Google Patents

Abstract

The invention discloses a hard alloy material and a preparation method and application thereof. The hard alloy comprises transition metal carbide and nonmetal carbide, wherein the mass ratio of the transition metal carbide to the nonmetal carbide is 1:4-9. The hard alloy fully exerts the strengthening effect of carbide crystals based on the synergistic effect of all components in the raw materials, and obviously improves the strength and toughness of the alloy material while greatly improving the hardness of the alloy material. The hard alloy adopts an integrated high-temperature high-pressure forging process, and simultaneously, the material is pressurized at high temperature, so that the crystal lattice orientation of the original carbide is changed, and the alloy material presents a fine crystal phase. The hard alloy has excellent hardness, red hardness, wear resistance and obdurability, and can meet the material requirements of various cutting tools and the requirements of parts in high-temperature environments.

Description

A kind of cemented carbide material and its preparation method and application

technical field

The invention relates to an alloy material, in particular to a cemented carbide material and its preparation method and application, and belongs to the technical field of alloy materials.

Background technique

In my country's cemented carbide manufacturing industry, there are two common methods. One is to use more than two kinds of metals with the same properties to mix, press and sinter, such as tungsten-cobalt alloy, iron-nickel alloy, copper-zinc alloy, etc.; One is to use two or more materials with different properties, such as non-metal and metal mixed by pressing and sintering. Representative alloys include ferrosilicon alloy, silicon-aluminum alloy, palladium-boron alloy, copper-boron alloy, iron-carbon alloy, etc. However, no matter what kind of material, what kind of preparation technology, and what kind of sintering process, the three-step preparation method of mixing-pressing-sintering is adopted. This process is already a mature and practical preparation method in the industry. The process first mixes the raw materials in a certain proportion, presses them into shape, and puts them in a furnace with a protective atmosphere for high-temperature sintering. During sintering, the furnace is accompanied by a protective gas pressure below 6MPa. In recent years, hot isostatic pressing of high-temperature sintered alloys and hot isostatic pressing of high-temperature sintered alloys are also less than or equal to 20 MPa during sintering.

From the above description, it can be seen that the performance of cemented carbide is closely related to the ratio of raw material components and the preparation process. The cemented carbide not only requires high hardness and good wear resistance, but also requires the alloy to have certain impact toughness and flexural toughness. However, In the field of alloys, hardness and strength, hardness and toughness are two contradictory characteristic attributes. Generally speaking, the higher the hardness of the alloy, the lower its strength and toughness. This feature obviously cannot meet the requirements of the existing industry. Alloy performance requirements.

Chinese patent (CN104831144) provides a composite cemented carbide material, which is made of nano-titanium carbide, nano-titanium nitride, tungsten carbide, niobium carbide, silicon carbide, yttrium oxide, aluminum carbide, titanium powder, tantalum carbide, zirconium carbide, Cobalt powder, silicon powder, nickel powder and boron carbide are the main raw materials. By adding rare earth elements, they combine with impurities such as oxygen and sulfur in the alloy to purify the grain boundaries and eliminate defects, so that the prepared alloy has high strength and toughness. Excellent wear resistance and thermal shock performance. However, the cemented carbide has a variety of raw materials, and has high requirements for raw materials. There are nano-scale raw materials, and there are still shortcomings such as insufficient strength and toughness.

To sum up, in the existing technology, it is still impossible to achieve high hardness of cemented carbide while greatly improving the strength and toughness of the material. The demand for high-quality cemented carbide in various industrial production fields needs to be met urgently.

Contents of the invention

Aiming at the problems existing in the prior art, the first object of the present invention is to provide a cemented carbide material. The alloy material uses transition metal carbides and non-metallic carbides as raw materials. Based on the synergistic effect of each component of the raw materials, the carbide crystal strengthening effect is fully exerted, and the hardness of the alloy material is also significantly increased. Strength and toughness.

The second object of the present invention is to provide a method for preparing cemented carbide materials. The method obtains the effective working pressure of ultra-high pressure required for the preparation by means of electric heating and pressurization, and at the same time pressurizes the material at a high temperature to change the The lattice orientation of the original carbide makes the alloy material present a fine crystal phase. By adjusting the current intensity and pressure, the method can realize the controllable adjustment of the hardness, strength and toughness of the alloy material.

The third object of the present invention is to provide a kind of application of cemented carbide material, the cemented carbide material provided by the present invention is based on the synergy of raw material component and preparation method, endows this alloy material with beneficial mechanical property, especially substantially Improve the hardness, red hardness, wear resistance, impact resistance and bending resistance of the alloy material to meet the material requirements of various cutting tools and parts in high temperature environments.

In order to achieve the above technical purpose, the present invention provides a cemented carbide material, including transition metal carbides and non-metal carbides; the mass ratio of the transition metal carbides to non-metal carbides is 1:4-9.

The present invention uses transition metal carbides and non-metal carbides, wherein the content of non-metal carbides is much higher than that of transition metal carbides. The purpose of doing this is to increase the hardness of the alloy while reducing the density of the alloy, thereby greatly improving the hardness of the alloy. The hardness and strength and toughness of the material. Further, the cemented carbide material does not contain oxides and nitrides. The oxides are easy to cause microcracks in the green body after high temperature and high pressure synthesis, resulting in a decrease in strength and toughness; while the nitrogen content of the nitrides is difficult to control, the nitrogen content Too high can make the phase transformation of cemented carbide beyond the controllable range, thereby reducing the hardness of cemented carbide.

As a preferred solution, the transition metal carbide is at least one of zirconium carbide, chromium carbide, titanium carbide and vanadium carbide.

As a preferred solution, the zirconium carbide is cubic polycrystal, the combined carbon content is between 5% and 10%, and the particle size is less than 5 μm.

As a preferred solution, the chromium carbide is a face-centered cubic lattice, the combined carbon content is between 4% and 7%, and the particle size is less than 5 μm.

As a preferred solution, the vanadium carbide is a cubic crystal, the combined carbon content is between 5% and 8%, and the particle size is less than 5 μm.

As a preferred solution, the vanadium carbide is a face-centered cubic lattice, the combined carbon content is between 5% and 8%, and the particle size is less than 5 μm.

As a preferred solution, the non-metallic carbide is boron carbide and/or silicon carbide.

As a preferred solution, the silicon carbide has a cubic crystal structure, which can be α-phase αsic or β-phase βsic, with a free carbon content between 5% and 10%, and a particle size of less than 5 μm.

As a preferred solution, the crystal structure of the boron carbide is a rhombohedral structure, the content of free carbon is between 10% and 20%, and the particle size is less than 5 μm.

In order to ensure the lattice coordination of non-metallic carbides and transition metal carbides, the crystals selected by the two should be similar or the same. In non-metallic carbides, the cubic silicon carbide and rhombohedral boron carbide are the hardness The highest crystal structure, therefore, the transition metal carbides used in the present invention all adopt cubic crystals. If the crystal selection is not performed according to the above requirements, it will lead to defects in the atomic bonding between non-metallic materials and transition metal materials in the synthesis process of high temperature and high pressure, resulting in a decrease in the hardness, strength and toughness of alloy materials.

As a preferred solution, the hard alloy includes the following components in mass percentage: 5-85% of boron carbide, 5-85% of silicon carbide, 2-13% of chromium carbide, 1-5% of vanadium carbide, 1% of titanium carbide ~5%.

As a preferred solution, the cemented carbide is composed of the following components in mass percentage: boron carbide 6-80%, silicon carbide 6-80%, chromium carbide 2-11%, vanadium carbide 1-3%, titanium carbide 1 to 3%. The composition ratio of cemented carbide should be strictly in accordance with the above ratio. If the total content of transition metal carbides is ≧30%, the hardness of the alloy material will drop significantly, down to about HRC60. If the total content of transition metals is ≦5%. At the same time, the brittleness of the alloy material becomes larger, and the bending strength and impact toughness decrease greatly.

The present invention also provides a method for preparing cemented carbide, comprising the following steps: uniformly mixing raw materials including transition metal carbides and non-metal carbides and then pressing to obtain an alloy embryo; extruding the alloy embryo at high temperature and then cooling , that is.

As a preferred solution, the purity of the raw material is not less than 99.5% powder and/or block.

As a preferred solution, the pressing method is press pressing, and the conditions are: the pressure is 15-20 MPa, and the time is 2-10 minutes.

As a preferred solution, the high-temperature extrusion method is a double-sided pressing machine or a six-sided pressing machine, and the conditions are: pressure 6-10 GPa, temperature 1400-1600 ° C, and time 10-60 minutes. In order to ensure that the effective working pressure of the alloy body is between 6 and 10 GPa, the system working pressure of the press should be between 10 and 16 GPa.

As a preferred solution, the heating method of the high-temperature extrusion is electric heating, and the current intensity is 1500-2500A.

The invention also provides an application of hard alloy material for preparing special cutting tools.

The raw materials of the alloy material provided by the present invention all appear in the physical properties of carbides, without oxides, nitrides and other substances, and are produced by synergizing with multiple composite carbides through high temperature and high pressure synthesis. After testing, the melting point of the alloy material is >1600°C, the hardness reaches above grade 9, second only to diamond, the Rockwell hardness is ≥80HRC, the density is 3.3～3.9g/cm ³ , and the bending strength is ≥1400N/c㎡, based on the above With excellent mechanical properties, this alloy material can meet the requirements of various cutting tool steels and components in high temperature environments.

Compared with the prior art, the excellent effects of the present invention are as follows:

1) The cemented carbide materials provided by the present invention use transition metal carbides and non-metallic carbides as raw materials. Based on the synergistic effect of each component between the raw materials, the carbide crystal strengthening effect is fully exerted, and the hardness of the alloy material is greatly improved. At the same time, the strength and toughness of the alloy material are significantly increased.

2) In the technical solution provided by the present invention, the material is subjected to high-temperature pressure at the same time through electric heating and six-sided top press to change the lattice orientation of the original carbide, so that the alloy material presents a fine crystal phase . The method controls the temperature by adjusting the magnitude of the current intensity to achieve the purpose of controlling the material of the cemented carbide, and can realize the controllable adjustment of the hardness, strength and toughness of the alloy material.

3) In the technical solution provided by the present invention, based on the synergy between the raw material components and the preparation method, the alloy material is endowed with beneficial mechanical properties, which not only greatly improves the hardness, red hardness, wear resistance, and impact resistance of the alloy material It also has unique physical and chemical properties such as non-magnetic, non-conductive, high temperature resistance, corrosion resistance and low density, which can meet the material requirements of various cutting tools and the needs of parts in high temperature environments.

detailed description

The present invention will be further described below in conjunction with the examples. The raw materials of the present invention are all obtained through commercial channels. The preparation methods of the present invention are conventional preparation methods in the field if there is no special instructions. The following examples are intended to illustrate the present invention rather than Further definition of the present invention.

Example 1

Boron carbide 68%, silicon carbide 7%, chromium carbide 15%, titanium carbide 8%, vanadium carbide 2%. The above five kinds of carbides are mixed and pressed into a cylindrical green body in proportion, assembled and formed on a press for high temperature and high pressure synthesis, the effective working temperature is 1600°C during synthesis, and the working pressure of the system is 11GPa. The effective work of the green body is ensured after the loss of pressure transmission during operation. Pressure≧7GPa. The cemented carbide has a density of 3.66g/cm ³ , a hardness of HRC86, and a bending strength of 1860N/c㎡.

Example 2

Silicon carbide 78%, zirconium carbide 6%, chromium carbide 13%, titanium carbide 2%, vanadium carbide 1%. The above five kinds of carbides are mixed and pressed into a cylindrical green body in proportion, assembled and formed, placed on a press for high temperature and high pressure synthesis, the effective working temperature is 1900°C during synthesis, and the working pressure of the press system is 10GPa. Body effective working pressure ≧ 6GPa. The cemented carbide has a density of 3.84g/cm ³ , a hardness of HRC84, and a bending strength of 2010N/c㎡.

Example 3

Boron carbide 83%, titanium carbide 12%, zirconium carbide 2%, vanadium carbide 3%, the above four kinds of carbides are mixed in proportion and pressed into a cylindrical green body, assembled and formed, placed on a press for high temperature and high pressure synthesis, effective during synthesis The working temperature is 2100°C, the working pressure of the press system is 13GPa, and the effective working pressure of the green body is guaranteed to be ≧7GPa after the pressure transmission loss of the studio. The cemented carbide density is 3.41g/cm ³ , the hardness is HRC89, and the bending strength is 1600N/c㎡.

Comparative example 1

Silicon carbide 62%, zirconium carbide 6%, chromium carbide 26%, magnesium carbide 4%, vanadium carbide 2%, the above five carbide substances are exactly the same as the five carbide substances in Implementation 2, but the proportions are different. The synthesis process requirements are exactly the same as in the implementation case 2, the effective working temperature is 1900°C, the system working pressure is 10GPa, the effective working pressure after the pressure transmission loss of the studio is ≧6GPa, and the obtained cemented carbide has a density of 3.30g/cm ³ and a hardness of HRC56. The hardness has dropped by 34%, the flexural strength is 2100N/c㎡, and the flexural strength has only increased by 4.3%, which is not worth the candle.

Comparative example 2

Boron carbide is 91.5%, titanium carbide is 6%, zirconium carbide is 1%, and vanadium carbide is 1.5%. The above four carbide substances are exactly the same as the four carbide substances in Example 3, but the proportions are different. Using the same synthesis process requirements as in Example 3, the effective working temperature is 2100°C, the working pressure of the press system is 13GPa, and the effective working pressure after pressure transmission loss during work is ≧7GPa. The obtained cemented carbide has a density of 3.28g/cm ³ and a hardness of HRC96, bending strength 800N/c㎡. Because the bending strength does not meet the standard, it becomes a waste product.

Claims (10)

1. A cemented carbide material characterized by: including transition metal carbides and non-metal carbides; the mass ratio of the metal carbide to the nonmetal carbide is 1:4-9.

2. A cemented carbide material according to claim 1, characterised in that: the transition metal carbide is at least one of tungsten carbide, zirconium carbide, chromium carbide, titanium carbide and vanadium carbide; the non-metal carbide is boron carbide and/or silicon carbide.

3. A cemented carbide material according to claim 2, characterised in that: comprises the following components in percentage by mass: 5-85% of boron carbide, 5-85% of silicon carbide, 2-13% of chromium carbide, 1-5% of vanadium carbide and 1-5% of titanium carbide.

4. A cemented carbide material according to claim 3, characterised in that: the composite material comprises the following components in percentage by mass: 6-80% of boron carbide, 6-80% of silicon carbide, 2-11% of chromium carbide, 1-3% of vanadium carbide and 1-3% of titanium carbide.

5. A method for producing a cemented carbide according to any one of claims 1-4, characterized in that: uniformly mixing raw materials including transition metal carbide and non-metal carbide, and pressing to obtain an alloy blank; and extruding the alloy blank at high temperature and cooling to obtain the alloy blank.

6. The method for preparing a cemented carbide material according to claim 5, wherein: the purity of the raw material is not less than 99.5% of powder and/or lumps.

7. The method for preparing a cemented carbide material according to claim 5, wherein: the pressing mode is pressing by a press, and the conditions are as follows: the pressure is 15-20 MPa, and the time is 2-10 min.

8. The method for preparing a cemented carbide material according to claim 5, characterized in that: the high-temperature extrusion mode is a double-faced top press or a six-faced top press, and the conditions are as follows: the pressure is more than or equal to 6GPa, the temperature is more than or equal to 1400 ℃, and the time is 10-60 min.

9. The method for preparing a cemented carbide material according to claim 8, wherein: the heating mode of the high-temperature extrusion is electric heating, and the current intensity is 1500-2500A.

10. Use of a cemented carbide material according to any one of claims 1 to 4, characterised in that: the method is used for preparing special cutting tools and parts in high-temperature environment.