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Preparing method for gradient hard alloy with surface rich in graphite phase

A technology of cemented carbide and graphite phase, applied in metal processing equipment, metal material coating technology, coating, etc., can solve the problems of long carburizing time, grain growth, low efficiency, etc., and improve carburizing efficiency , small particle size and simple process

Active Publication Date: 2017-08-18
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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  • Preparing method for gradient hard alloy with surface rich in graphite phase

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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 of surface graphite-rich phase 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 added to a...

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Abstract

The invention discloses a preparing method for a gradient hard alloy with the surface rich in graphite phase. The preparing method is characterized in that firstly, heat preservation is conducted for 2-4 h at the temperature ranging from 550 DEG C to 750 DEG C, and a hard alloy raw blank removing a forming agent is formed, wherein the porosity of the hard alloy raw blank ranges from 25% to 40%; then, the three substances including amorphous Si-C-O wrapping TiH2 core / shell structure powder, a multi-wall carbon nano tube and Na2CO3 are mixed according to the weight percent of 1:2:1, and then a hydrogen-containing carburizing medium is prepared, wherein the outer diameter is smaller than 8 nm, the length is smaller than 30 microns, and the specific surface area is larger than 350 m<2> / g; then, the raw blank is embedded in the hydrogen-containing carburizing medium and is compacted under the pressure of 5-15 MPa; and finally, liquid phase sintering is conducted, and the gradient hard alloy with the surface rich in graphite phase is prepared. The preparing method solves the problems that in the existing technology, grain growth is serious, the carburization time is long, and efficiency is low; and in the sintering process, the gradient hard alloy with the surface rich in graphite phase is prepared in 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 Applications(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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