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A kind of preparation method of gradient cemented carbide with graphite-rich phase on the surface

A technology of cemented carbide and graphite phase, which is applied in metal processing equipment, metal material coating technology, solid-state diffusion coating, etc., can solve the problems of long carburizing time, grain growth, and low efficiency, and achieve high carburizing The effect of carbon efficiency, small particle size and simple process

Active Publication Date: 2018-09-28
SICHUAN UNIV
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Problems solved by technology

[0005] The present invention aims at the problems of severe grain growth, long carburizing time and low efficiency in the "sintering + carburizing" process when preparing gradient hard alloys with graphite-rich phases on the surface. Remove the molding agent to form a porous green body, and then coat the amorphous Si-C-O with TiH 2 core / shell structure powder, multi-walled carbon nanotubes, Na 2 CO 3 The mixed planetary ball mill is uniformly mixed to form a hydrogen-containing carburizing medium, and then the porous green body is placed in the carburizing medium and compacted, and finally a gradient cemented carbide with a graphite-rich phase on the surface is formed in situ during liquid phase sintering

Method used

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  • A kind of preparation method of gradient cemented carbide with graphite-rich phase on the surface

Examples

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example 1

[0019] Example 1: Prepare the gradient cemented carbide with graphite-rich phase on the surface as follows:

[0020] (1) Preparation of the release agent cemented carbide green body: Weigh various raw material powder ingredients by weight percentage, of which Co accounts for 8wt%, TiC accounts for 5wt%, TaC accounts for 2wt%, and WC is the balance; the weighed powder Mixed and ball milled for 45 hours, filtered with a 400-mesh screen, dried at 90°C, mixed with butadiene rubber molding agent according to 80% of the weight of the cemented carbide powder, and pressed under a pressure of 340MPa to obtain a cemented carbide green body; cemented carbide raw The blank is kept in a vacuum sintering furnace at 590°C for 2 hours, the heating rate is 2°C / min, and the vacuum degree is 15Pa, forming a cemented carbide green body with a porosity of 30% and the removal of the forming agent;

[0021] (2) Preparation of hydrogen-containing carburizing medium: first weigh TiH with a particle si...

example 2

[0024] Example 2: Prepare the gradient cemented carbide with graphite-rich phase on the surface according to the following steps:

[0025] (1) Preparation of green body of cemented carbide with release agent: Weigh various raw material powder ingredients according to weight percentage, among which Co accounts for 16wt%, and WC is the balance; mix the weighed powders and pass through 48h ball milling, 400 mesh screen Filtrate, dry at 91°C, mix in 70% of the weight of cemented carbide powder with butadiene rubber molding agent, press and form under a pressure of 330MPa to obtain a cemented carbide green body; keep the cemented carbide green body at 700°C for 3 hours in a vacuum sintering furnace , the heating rate is 4°C / min, and the vacuum degree is 18Pa, forming a cemented carbide green body with a porosity of 36% and removing the forming agent;

[0026] (2) Preparation of hydrogen-containing carburizing medium: first weigh TiH with a particle size of 1.1 μm 2 The powder is a...

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Abstract

The invention discloses a preparation method of a gradient cemented carbide with a graphite-rich surface, which is characterized in that it first heats the cemented carbide at 550-750°C for 2-4 hours to form a cemented carbide with a porosity of 25%-40%. Green body; then amorphous Si-C-O-coated TiH2 core / shell structure powder, multi-walled carbon nanotubes with outer diameter less than 8nm, length less than 30μm and specific surface area greater than 350m2 / g, Na2CO3 three kinds of substances by weight The ratio of 1:2:1 is mixed to prepare a hydrogen-containing carburizing medium; then the green body is embedded in the hydrogen-containing carburizing medium and compacted under a pressure of 5~15MPa; finally, liquid phase sintering is carried out to prepare a surface graphite-rich phase gradient cemented carbide. The invention overcomes the problems of severe grain growth, long carburizing time and low efficiency in the prior art, and prepares gradient hard alloy with graphite-rich phase on the surface during the sintering process.

Description

technical field [0001] The invention relates to a preparation method of cemented carbide, in particular to a preparation method of gradient cemented carbide whose surface is rich in graphite phase, and belongs to the field of hard materials. Background technique [0002] Cemented carbide has the characteristics of high strength, high hardness, high elastic modulus, wear resistance, corrosion resistance, low thermal expansion coefficient and high chemical stability. It is known as "industrial teeth" and is widely used as cutting tools and drilling tools , wear-resistant parts, etc. In order to improve its friction and wear performance, carburizing treatment can be carried out on the surface to make the surface rich in graphite phase, so as to obtain a good anti-friction effect. [0003] CN105331868A discloses a preparation method of gradient structure WC-Co cemented carbide. The invention uses the WC-Co cemented carbide billet with a porosity of 15-40% and uniform distributi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C29/08C22C1/05B22F3/10C23C8/64
CPCC22C1/051C22C29/08C23C8/64B22F3/1007B22F2998/10B22F2999/00B22F2201/30B22F2201/20B22F1/10B22F3/1021B22F3/02
Inventor 郭智兴熊计李深厚
Owner SICHUAN UNIV
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