阅读说明：本技术 应用于切削刀具的超细晶粒硬质合金及其制备方法 (Ultra-fine grain hard alloy applied to cutting tool and preparation method thereof ) 是由 李世安 于 2019-11-20 设计创作，主要内容包括：本发明公开了一种应用于切削刀具的超细晶粒硬质合金及其制备方法,超细晶粒硬质合金的组分及各组分质量百分比为：晶粒度为0.4-0.6μm的碳化钨粉：89.9％；钴粉：7.2％；碳化钒：0.3％；碳化钽：2.6％。超细晶粒硬质合金能够同时达到K类,P类,M类硬质合金的性能特点,能够同时应用于不同类型切削刀具和不同被加工材料。(The invention discloses an ultra-fine grain hard alloy applied to a cutting tool and a preparation method thereof, wherein the ultra-fine grain hard alloy comprises the following components in percentage by mass: tungsten carbide powder with grain size of 0.4-0.6 μm: 89.9 percent; cobalt powder: 7.2 percent; vanadium carbide: 0.3 percent; tantalum carbide: 2.6 percent. The ultra-fine grain hard alloy can simultaneously reach the performance characteristics of K-type, P-type and M-type hard alloys, and can be simultaneously applied to different types of cutting tools and different processed materials.)

1. The ultra-fine grain hard alloy applied to the cutting tool is characterized by comprising the following components in percentage by mass:

tungsten carbide powder with grain size of 0.4-0.6 μm: 89.9 percent;

cobalt powder: 7.2 percent;

vanadium carbide: 0.3 percent;

tantalum carbide: 2.6 percent.

2. The ultra fine grained cemented carbide for use in cutting tools according to claim 1,

the Fisher size of the cobalt powder is less than 0.8 mu m.

3. The ultra fine grained cemented carbide for use in cutting tools according to claim 1,

the Ferris grain size of the vanadium carbide is less than 0.8 mu m.

4. The ultra fine grained cemented carbide for use in cutting tools according to claim 1,

the Freund's grain size of the tantalum carbide is less than 1.0 μm.

5. A method for preparing ultra fine grained cemented carbide for cutting tools according to any of claims 1 to 4, characterized in that the method comprises the steps of:

mixing the components in percentage by mass, and then carrying out ball milling to obtain a ball grinding material;

granulating by using a ball mill material to obtain granules;

pressing by adopting the granules to obtain pressed strips;

and (4) carrying out pressure sintering on the pressed strip through a pressure sintering furnace to obtain the required hard alloy.

6. The production method according to claim 5,

the ball milling process is as follows:

mixing the components in percentage by mass and placing the mixture into a ball mill;

adding absolute alcohol and PEG4000 into a ball mill;

and sealing the ball mill for ball milling.

7. The production method according to claim 6,

the addition amount of anhydrous alcohol is 350ml per kg of raw materials.

8. The production method according to claim 5,

the ball-material ratio of ball milling is as follows: 4:1.

9. The production method according to claim 5,

in the pressure sintering, the pressure: 3 MPa; sintering temperature: 1420 ℃.

Technical Field

The invention relates to an ultra-fine grain hard alloy applied to a cutting tool and a preparation method thereof.

Background

At present, machining usually comprises turning, milling, grooving/parting, threading, boring and the like, different materials are machined, and the ideal cutting effect can be realized only by using a hard alloy mark matched with the materials.

For example, turning is generally a continuous process, and places great importance on the wear resistance of the cemented carbide material, and has a high requirement on the hardness of the cemented carbide material. The traditional hard alloy material is difficult to ensure that the hard alloy has extremely high strength while ensuring the hardness, the hard alloy material is usually very good in wear resistance, but the hard alloy cutter has extremely short service life due to insufficient strength.

Milling, which is an intermittent process, places great attention on the strength of cemented carbide materials in order to ensure that the tool has sufficient strength. The traditional hard alloy material improves the strength of the material, and simultaneously, the hardness is sharply reduced. Therefore, the high strength of the hard alloy material is extremely difficult to be considered while ensuring that the hard alloy cutter has enough strength.

Grooving/parting machining, because such machining is continuous, large in cutting depth, large in contact area of cutting edges, and very demanding in the requirements on the material of the cemented carbide tool, the material is guaranteed to have both sufficient strength and extremely high hardness. The hard alloy material is required to have hardness and strength, and is not different from the coexistence of water and fire.

Traditional cemented carbide grades fall into three categories:

class K (K10-K40): physical and mechanical properties: hardness: 86HRA-91HRA, strength: 2200-3400N/mm²Density: 14.2-14.8g/mm³(ii) a The main processing objects are as follows: cast iron, non-ferrous metals, wood, stone, etc.

Class P (K05-P40): physical and mechanical properties: hardness: 89.5-92.5 HRA, intensity: 2000-2600N/mm²Density: 12-13.5g/mm³(ii) a The main processing objects are as follows: general low carbon steel, mild steel, and the like.

Class M (M10-M30): physical and mechanical properties: hardness: 89.5HRA-91.5HRA, intensity: 2200-2800N/mm²Density: 14.2-14.8g/mm³(ii) a The main processing objects are as follows: general quenched steel, hard steel, stainless steel, etc. are processed.

The traditional hard alloy grades have the defects that a single hard alloy grade has a corresponding processing object, different hard alloy grades are difficult to use universally, namely the hard alloy grades are exchanged universally and the material characteristics of hard alloy materials are difficult to exert, so that the cost of a hard alloy cutter is greatly increased, and serious resource waste is caused.

Compared with foreign hard alloy, the traditional hard alloy in China is laggard in production technology, old in equipment, poor in product performance and unstable in quality, and is difficult to compete with foreign hard alloy enterprises. The traditional process of the cemented carbide grade falls behind, factors such as various technical barriers and the like also greatly limit the updating iteration of cemented carbide cutting tool products, and the gap between the domestic cemented carbide cutting tool and the foreign countries is expanded more and more.

At present, most of hard alloy manufacturers are difficult to realize that a single hard alloy material is used for different cutting modes and a single hard alloy grade is used for processing different processed materials.

Different cemented carbide grades can be used for producing corresponding cemented carbide cutters according to different cutting modes and different materials to be machined, but due to the fact that the machining modes and the application are different and the number of cemented carbide cutter products is as many as thousands, the purpose that corresponding cemented carbide materials can not be used according to different cutting modes and different materials to be machined is achieved almost.

Often, a hard alloy manufacturer can only consider a certain point of a full cutting mode or select a corresponding hard alloy material according to the cutting of a certain material. Therefore, the produced product has poor performance and lacks of market competitiveness. The product price is low, the profit of the enterprise is gradually reduced, and the product is eliminated by the market in the long term.

Different cemented carbide materials have different shrinkage ratios during sintering, which we refer to in the art as K-values, and typically the K-values of cemented carbide materials are between 1.17 and 1.25. To achieve the proper product size, the K values of different materials are different for the same product.

There are several thousands of types of cemented carbide tools, and different materials have different K values (shrinkage coefficients). For example: according to different materials to be machined, the common cemented carbide cutting tool-CNMG 120408, generally used cemented carbide materials include K-type (K10-K40), P-type (K05-P40) and M-type (M10-M30), i.e. at least three to five sets of dies are required for one cemented carbide cutting tool. The price of a set of simple hard alloy cutter mold is 6000 plus 9000 yuan, and the price of a high-end hard alloy cutter mold is 25000 plus 30000 yuan. It is thought that for most of the carbide manufacturers, this is a huge investment, which limits the development of the carbide manufacturers to a great extent.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects of the prior art and provide the ultrafine grain hard alloy applied to the cutting tool, which can simultaneously achieve the performance characteristics of K-type, P-type and M-type hard alloys and can be simultaneously applied to different types of cutting tools and different processed materials.

In order to solve the technical problems, the technical scheme of the invention is as follows: an ultra-fine grain hard alloy applied to a cutting tool comprises the following components in percentage by mass:

tungsten carbide powder with grain size of 0.4-0.6 μm: 89.9 percent;

cobalt powder: 7.2 percent;

vanadium carbide: 0.3 percent;

tantalum carbide: 2.6 percent.

Further, the cobalt powder has a fisher particle size of <0.8 μm.

Further, the fisher's grain size of the vanadium carbide is less than 0.8 μm.

Further, the Freund's grain size of the tantalum carbide is <1.0 μm.

The invention also provides a preparation method of the ultrafine grain hard alloy applied to the cutting tool, which comprises the following steps:

mixing the components in percentage by mass, and then carrying out ball milling to obtain a ball grinding material;

granulating by using a ball mill material to obtain granules;

pressing by adopting the granules to obtain pressed strips;

and (4) carrying out pressure sintering on the pressed strip through a pressure sintering furnace to obtain the required hard alloy.

Further, the process of ball milling is as follows:

mixing the components in percentage by mass and placing the mixture into a ball mill;

adding absolute alcohol and PEG4000 into a ball mill;

and sealing the ball mill for ball milling.

Further, the amount of absolute alcohol added was 350ml per kg of the raw material.

Further, the ball-milling ball-material ratio is as follows: 4:1.

Further, in the pressure sintering, the pressure: 3 MPa; sintering temperature: 1420 ℃.

After the technical scheme is adopted, the invention has the following beneficial effects:

1. the ultra-fine grain hard alloy can simultaneously reach the performance characteristics of K-type, P-type and M-type hard alloys.

2. The ultra-fine grain hard alloy can be simultaneously applied to different types of cutting tools and different processed materials.

3. Because the ultra-fine grain hard alloy is of a single mark, the coefficient of contraction (K value) is also single and unchanged, the investment of the die can be greatly reduced, and the cost of the die can be at least reduced by 1/3-1/5.

4. Compared with the traditional hard alloy grades, the hardness, the strength, the red hardness and the wear resistance of the ultrafine grain hard alloy are far higher than those of the traditional hard alloy grades.

5. Compared with the traditional hard alloy M alloy, the material cost is high, the production cost is high, the performance of the alloy is difficult to meet the requirement of the fast-developing hard alloy cutting industry, and the superfine grain hard alloy material has low cost and low production cost.

6. The ultra-fine grain hard alloy can be applied to various different processing modes and complex working conditions such as turning, milling, grooving, thread cutting, boring turning and the like, and can be used for processing various materials such as cast iron, mild steel, hard steel, quenched steel, stainless steel, high-temperature alloy, acrylic, wood, nonferrous metal and the like.

Drawings

Fig. 1 is a gold phase diagram of an ultra fine grain cemented carbide according to the present invention applied to a cutting tool.

Detailed Description

The invention provides an ultra-fine grain hard alloy applied to a cutting tool and a preparation method thereof, and a person skilled in the art can realize the purpose by properly improving process parameters by referring to the content. It is expressly intended that all such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope of the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

An ultra-fine grain hard alloy applied to a cutting tool comprises the following components in percentage by mass:

tungsten carbide powder having a grain size of 0.4 to 0.6 μm as a hard phase: 89.9 percent;

cobalt powder as binder phase: 7.2 percent;

vanadium carbide as a grain growth inhibition phase: 0.3 percent;

tantalum carbide as red hardness increasing phase: 2.6 percent.

Further, the cobalt powder has a fisher particle size of <0.8 μm. The cobalt content of the cobalt powder is more than 99.8%;

further, the fisher's grain size of the vanadium carbide is less than 0.8 μm.

Further, the Freund's grain size of the tantalum carbide is <1.0 μm.

In the present invention, tungsten carbide powder is used as the hard phase, and ultra-fine grain tungsten carbide will have extremely high hardness and high wear resistance.

The content of Co is accurately calculated, so that the basic function of a binder phase is ensured, and the high hardness of the hard alloy can be ensured not to be reduced.

The Vanadium Carbide (VC) is different from the traditional superfine hard alloy material, and the Vanadium Carbide (VC) is used as a grain growth and coarsening inhibiting phase, has better inhibiting effect and is 3-5 times of the effect of inhibiting the grain growth and coarsening of the traditional inhibitor.

The tantalum carbide reduces the material cost of the present invention, and can improve the red hardness of the material and expect a certain effect of suppressing grain growth.

The preparation method of the ultrafine grain hard alloy applied to the cutting tool comprises the following steps:

mixing the components in percentage by mass, and then carrying out ball milling to obtain a ball grinding material;

granulating by using a ball mill material to obtain granules;

pressing by adopting the granules to obtain pressed strips;

and (4) carrying out pressure sintering on the pressed strip through a pressure sintering furnace to obtain the required hard alloy.

Further, the process of ball milling is as follows:

mixing the components in percentage by mass and placing the mixture into a ball mill;

adding absolute alcohol and PEG4000 into a ball mill;

and sealing the ball mill for ball milling.

Further, the amount of absolute alcohol added was 350ml per kg of the raw material.

Further, the ball-milling ball-material ratio is as follows: 4:1.

Further, in the pressure sintering, the pressure: 3 MPa; sintering temperature: 1420 ℃.

The physical and mechanical properties of the ultra-fine grain hard alloy prepared by the invention are as follows:

hardness: HRA 93;

density: 14.4-14.6g/cm³；

Strength: >3000 (TRS/MPa);

cobalt magnetic: 6.8 percent;

coercive force: 26-28 KA/m.

In order that the present invention may be more readily and clearly understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings.

An ultra-fine grain hard alloy applied to a cutting tool comprises the following components in percentage by mass:

tungsten carbide powder: 26970 g;

cobalt powder: 2160 g;

vanadium carbide: 90g of the total weight of the mixture;

tantalum carbide: 780 g.

The Fisher size of the cobalt powder is less than 0.8 mu m. The cobalt content of the cobalt powder is more than 99.8%;

the Ferris grain size of the vanadium carbide is less than 0.8 mu m.

The Freund's grain size of the tantalum carbide is less than 1.0 μm.

Fisher particle size of tungsten carbide powder: 0.6um (supplied state), 0.57um (ground state).

The preparation method of the ultrafine grain hard alloy applied to the cutting tool comprises the following steps:

mixing the components in percentage by mass, and then carrying out ball milling to obtain a ball grinding material;

granulating by using a ball mill material to obtain granules;

pressing by adopting the granules to obtain pressed strips;

and (4) carrying out pressure sintering on the pressed strip through a pressure sintering furnace to obtain the required hard alloy.

And (3) vacuum packaging the prepared hard alloy powder by using a special transparent vacuum bag, or packaging by using a special packaging bag and filling protective gas to prevent the hard alloy powder from being oxidized or absorbing moisture.

The ball milling process is as follows:

mixing the components in percentage by mass and placing the mixture into a ball mill;

adding 10500ml of absolute alcohol and PEG40001.2kg into a ball mill;

the ball mill is sealed and ball-milled for 48 hours.

The addition amount of anhydrous alcohol is 350ml per kg of raw materials.

The ball-material ratio of ball milling is as follows: 4:1.

In the pressure sintering, the pressure: 3 MPa; sintering temperature: 1420 ℃.

The obtained hard alloy is made into an identification strip, a metallographic diagram is shown in figure 1, and the physical and mechanical properties obtained by analyzing the identification strip are as follows:

the identification result of the identification strip meets the physical performance index to be obtained, and the batch of hard alloy materials is qualified.

The above embodiments are described in further detail to solve the technical problems, technical solutions and advantages of the present invention, and it should be understood that the above embodiments are only examples of the present invention and are not intended to limit the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.