阅读说明：本技术 一种数控机床用硬质合金及其制备方法 (Hard alloy for numerical control machine tool and preparation method thereof ) 是由 张好平 张振伟 许俊东 孙伟 邹庆锋 张军锋 黄为龙 杨素平 高贵鹏 刘丰男 李 于 2020-04-26 设计创作，主要内容包括：本发明涉及数控机床用硬质合金技术领域,尤其是一种数控机床用硬质合金及其制备方法。该种数控机床用硬质合金,主要由原料组成：碳化钨、钴、钌粉、钐粉0.5-1份、羰基镍粉、碳化钒、碳化钽、碳化铌和碳化钛。本发明的一种数控机床用硬质合金及其制备方法,在高温作用下钐促进α-Co部分向β-Co转变,合金总体韧性提高,与此同时金属钌析出六方晶胞的晶体,合金由于α-Co减少而引起的硬度损失被析出的钌晶体补充,钌与钴的结合既能提高合韧性又能确保合金保持较高硬度,钐的极少量晶体析出,均布于六方结构的α-Co和六方结构的钌中,增强合金整体致密性,提高耐磨性能。(The invention relates to the technical field of hard alloy for a numerical control machine tool, in particular to hard alloy for the numerical control machine tool and a preparation method thereof, wherein the hard alloy mainly comprises raw materials of tungsten carbide, cobalt, ruthenium powder, 0.5-1 part of samarium powder, carbonyl nickel powder, vanadium carbide, tantalum carbide, niobium carbide and titanium carbide.)

1. The hard alloy for the numerical control machine tool is characterized in that: the material mainly comprises the following raw materials in parts by weight: 80-90 parts of tungsten carbide, 0.1-0.6 part of cobalt, 0.01-0.08 part of ruthenium powder, 0.5-1 part of samarium powder, 0.1-0.3 part of carbonyl nickel powder, 0.1-0.8 part of vanadium carbide, 5-8 parts of tantalum carbide, 0.8-1.5 parts of niobium carbide and 1-2 parts of titanium carbide.

2. The cemented carbide for a numerical control machine tool according to claim 1, wherein: the material mainly comprises the following raw materials in parts by weight: 85 parts of tungsten carbide, 0.8 part of cobalt, 0.05 part of ruthenium powder, 0.7 part of samarium powder, 0.2 part of nickel carbonyl powder, 0.4 part of vanadium carbide, 6 parts of tantalum carbide, 1.1 part of niobium carbide and 1.5 parts of titanium carbide.

3. The cemented carbide for a numerical control machine tool according to claim 1 or 2, wherein: the particle size of the tungsten carbide is 0.2-0.3 mu m, the particle size of the cobalt is 0.4-0.8 mu m, the particle size of the ruthenium powder is 0.5-0.8 mu m, the particle size of the samarium powder is 0.2-0.8 mu m, the particle size of the nickel carbonyl powder is 0.2-0.5 mu m, the particle size of the vanadium carbide is 0.2-0.6 mu m, the particle size of the tantalum carbide is 1-1.5 mu m, the particle size of the niobium carbide is 1-1.5 mu m, and the particle size of the titanium carbide is 1-2 mu m.

4. The method for preparing a cemented carbide for a numerical control machine according to claim 3, wherein: the method comprises the following steps:

s1, taking all the raw materials according to the specified mass part, uniformly mixing, adding a ball milling medium, placing the mixture into a ball mill for ball milling, wherein the liquid-solid ratio is 600-650m L/kg, the ball-material ratio is 7.5-9:1, the rotating speed of the ball mill is controlled at 200-260r/min, and the ball milling time is 40-60h, so as to obtain a wet mixed material A;

s2: putting the wet mixture A obtained in the step S1 into a dryer for drying for 30-60min, recovering a ball milling medium, then carrying out circulating cooling by using chilled water, screening to obtain a mixture B, and then carrying out wax doping and granulation on the mixture B in a sealed state to obtain a mixture C;

s3: carrying out isostatic pressing on the mixture C obtained in the step S2, controlling the pressure at 180-300MPa, and preparing a green compact;

s4: and (4) preparing the high-pressure and high-temperature resistant hard alloy from the pressed compact prepared in the step S3 by adopting a low-pressure positive carbon high-temperature sintering method.

5. The method for preparing a cemented carbide for a numerical control machine according to claim 4, wherein: the ball milling medium in the step S1 comprises the following components in percentage by weight: 97.5-99.2 Wt% of absolute alcohol and 0.8-2.5 Wt% of oleic acid.

6. The method for preparing a cemented carbide for a numerical control machine according to claim 4, wherein: the low-pressure positive carbon high-temperature sintering method in the step S4 comprises the following steps:

(1) charging and vacuumizing;

(2) heating to 350-;

(3) heating to 1100 ℃ and 1300 ℃, and preserving the temperature for 0.5-2 h;

(4) carburizing at the temperature of 1400 ℃ and 1500 ℃ for 0.5-2 h;

(5) heating to the final sintering temperature of 1600 ℃, filling argon gas for pressurization, controlling the pressure at 5-10MPa, and keeping the temperature and pressurizing for 1-2 h; and (5) reducing the pressure, cooling and discharging.

Technical Field

The invention relates to the technical field of hard alloy for a numerical control machine tool, in particular to hard alloy for the numerical control machine tool and a preparation method thereof.

Background

The numerical control machine tool is a short name of a digital control machine tool (Computer numerical control machine tools), and is an automatic machine tool provided with a program control system. The control system is capable of logically processing and decoding a program defined by a control code or other symbolic instructions, represented by coded numbers, which are input to the numerical control device via the information carrier. After operation, the numerical control device sends out various control signals to control the action of the machine tool, and the parts are automatically machined according to the shape and the size required by the drawing. The numerical control machine tool well solves the problem of machining of complex, precise, small-batch and various parts, is a flexible and high-efficiency automatic machine tool, represents the development direction of the control technology of modern machine tools, and is a typical mechanical and electrical integration product.

The parts such as the anchor clamps on the digit control machine tool adopt carbide to support, and this type of part has better requirement to hardness, toughness and wear resistance, and current carbide spare part for the digit control machine tool adds comparatively expensive batching for improving hardness, toughness and wear resistance more, leads to that although each aspect performance is promoted, carbide cost is improved relatively. Therefore, the technical problem to be solved by those skilled in the art is how to provide a cemented carbide for a numerical control machine tool, which has the advantages of low cost, high hardness, strong toughness and excellent wear resistance.

Disclosure of Invention

The invention aims to provide a hard alloy for a numerical control machine tool and a preparation method thereof, overcomes the defects of the prior art, and improves the hardness, toughness and wear resistance of the hard alloy on the basis of reducing the preparation cost of the hard alloy.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a hard alloy for a numerical control machine tool is mainly composed of the following raw materials in parts by weight: 80-90 parts of tungsten carbide, 0.1-0.6 part of cobalt, 0.01-0.08 part of ruthenium powder, 0.5-1 part of samarium powder, 0.1-0.3 part of carbonyl nickel powder, 0.1-0.8 part of vanadium carbide, 5-8 parts of tantalum carbide, 0.8-1.5 parts of niobium carbide and 1-2 parts of titanium carbide.

Further, the material mainly comprises the following raw materials in parts by weight: 85 parts of tungsten carbide, 0.8 part of cobalt, 0.05 part of ruthenium powder, 0.7 part of samarium powder, 0.2 part of nickel carbonyl powder, 0.4 part of vanadium carbide, 6 parts of tantalum carbide, 1.1 part of niobium carbide and 1.5 parts of titanium carbide.

Further, the particle size of tungsten carbide is 0.2-0.3 μm, the particle size of cobalt is 0.4-0.8 μm, the particle size of ruthenium powder is 0.5-0.8 μm, the particle size of samarium powder is 0.2-0.8 μm, the particle size of nickel carbonyl powder is 0.2-0.5 μm, the particle size of vanadium carbide is 0.2-0.6 μm, the particle size of tantalum carbide is 1-1.5 μm, the particle size of niobium carbide is 1-1.5 μm, and the particle size of titanium carbide is 1-2 μm.

A preparation method of hard alloy for a numerical control machine tool comprises the following steps:

s1, taking all the raw materials according to the specified mass part, uniformly mixing, adding a ball milling medium, placing the mixture into a ball mill for ball milling, wherein the liquid-solid ratio is 600-650m L/kg, the ball-material ratio is 7.5-9:1, the rotating speed of the ball mill is controlled at 200-260r/min, and the ball milling time is 40-60h, so as to obtain a wet mixed material A;

s2: putting the wet mixture A obtained in the step S1 into a dryer for drying for 30-60min, recovering a ball milling medium, then carrying out circulating cooling by using chilled water, screening to obtain a mixture B, and then carrying out wax doping and granulation on the mixture B in a sealed state to obtain a mixture C;

s3: carrying out isostatic pressing on the mixture C obtained in the step S2, controlling the pressure at 180-300MPa, and preparing a green compact;

s4: and (4) preparing the high-pressure and high-temperature resistant hard alloy from the pressed compact prepared in the step S3 by adopting a low-pressure positive carbon high-temperature sintering method.

Further, the ball milling medium in step S1 comprises the following components in percentage by weight: 97.5-99.2 Wt% of absolute alcohol and 0.8-2.5 Wt% of oleic acid.

Further, the low-pressure positive carbon high-temperature sintering method in step S4 includes the following steps:

(1) charging and vacuumizing;

(2) heating to 350-;

(3) heating to 1100 ℃ and 1300 ℃, and preserving the temperature for 0.5-2 h;

(4) carburizing at the temperature of 1400 ℃ and 1500 ℃ for 0.5-2 h;

(5) heating to the final sintering temperature of 1600 ℃, filling argon gas for pressurization, controlling the pressure at 5-10MPa, and keeping the temperature and pressurizing for 1-2 h; and (5) reducing the pressure, cooling and discharging.

The alloy has the advantages that the alloy has α -Co with two crystal structures of hexagonal structures and β -Co with face-centered cubic structure, β -Co with the hexagonal structure has excellent deformation coordination, β -Co has excellent strength, β -Co is converted to β -Co at the high temperature of above 400 ℃, in the prior art, metallic zirconium or rare earth elements are mostly selected to be added to enhance a Co bonding phase, so that the transformation from α -Co to β -Co is inhibited, and the hard alloy with stronger toughness is obtained, however, the method reduces the hardness of the hard alloy to a certain extent.

In addition, the vanadium carbide is added to reduce the sensitivity of the performance of the hard alloy to the sintering temperature and time, so that the range of the sintering temperature and time for which the magnetic force and hardness of the hard alloy are qualified is enlarged; adding a composite grain growth inhibitor consisting of tantalum carbide, niobium carbide and titanium carbide to inhibit the growth of tungsten carbide grains, so that the grain size of WC in the hard alloy is less than 0.2 mu m, and further enhancing the hardness of the hard alloy; and a small amount of carbonyl nickel powder is added, so that the infiltration is uniform in the powder sintering process, and the toughness of the hard alloy is further improved.

Compared with the prior art, the hard alloy for the numerical control machine tool and the preparation method thereof have the advantages that the cost of raw materials is reduced, samarium promotes α -Co to be partially converted to β -Co under the action of high temperature, the overall toughness of the alloy is improved, meanwhile, metal ruthenium is separated out to form crystals of hexagonal unit cells, hardness loss of the alloy caused by reduction of α -Co is supplemented by the separated ruthenium crystals, the combination of ruthenium and cobalt can improve the toughness and ensure that the alloy keeps high hardness, a small amount of samarium crystals are separated out and are uniformly distributed in α -Co with a hexagonal structure and ruthenium with a hexagonal structure, the overall compactness of the alloy is enhanced, and the wear resistance is improved.

Detailed Description