A kind of in-situ preparation method of surface self-lubricating cemented carbide

A cemented carbide, in-situ preparation technology, applied in the direction of metal material coating process, solid diffusion coating, coating, etc., can solve the problems of long carburizing time, grain growth, low efficiency, etc., to improve carburizing Effects of carbon efficiency, small particle size, and simple process

Active Publication Date: 2018-10-02
SICHUAN UNIV
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Problems solved by technology

[0005] The present invention aims at the problems of serious grain growth, long carburizing time and low efficiency in the "sintering + carburizing" process in the preparation of surface self-lubricating hard alloy, and proposes to remove the forming agent from the hard alloy compact to form a porous green body, and then the amorphous Al 2 o 3 coated TiH 2 The core / shell structure powder and nano-graphite mixed planetary ball mill are 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 the surface is self-lubricated in situ during liquid phase sintering Carbide

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  • A kind of in-situ preparation method of surface self-lubricating cemented carbide

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example 1

[0018] Example 1: Prepare surface self-lubricating carbide in situ according to the following steps:

[0019] (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 20wt%, and WC is the balance; mix the weighed powder and pass through 48h ball milling, 400 mesh screen Filtrate, dry at 86°C, mix 90% of the weight of cemented carbide powder with Buna-Na rubber molding agent, press and form under a pressure of 340MPa to obtain a cemented carbide green body; keep the cemented carbide green body at 570°C for 3 hours in a vacuum sintering furnace , the heating rate is 2°C / min, the vacuum degree is 21Pa, and the cemented carbide green body with a porosity of 27% and the removal of the forming agent is formed;

[0020] (2) Preparation of hydrogen-containing carburizing medium: first weigh TiH with a particle size of 0.6 μm 2 The powder is added to absolute ethanol ...

example 2

[0023] Example 2: Prepare surface self-lubricating carbide in situ according to the following steps:

[0024] (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 1wt%, and WC is the balance; the weighed powder Mixed and ball milled for 60 hours, filtered with a 400-mesh screen, dried at 92°C, mixed with butadiene rubber molding agent according to 95% of the weight of the cemented carbide powder, and pressed under a pressure of 310MPa to obtain a cemented carbide green body; cemented carbide raw The blank is kept in a vacuum sintering furnace at 640°C for 3 hours, the heating rate is 5°C / min, and the vacuum degree is 20Pa, forming a cemented carbide green body with a porosity of 35% and the removal of forming agents;

[0025] (2) Preparation of hydrogen-containing carburizing medium: first weigh TiH with a particle size of 1.5 ...

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Abstract

The invention discloses an in-situ preparation method of a hard alloy achieving surface self-lubrication. The in-situ preparation method of the hard alloy achieving surface self-lubrication is characterized in that forming-agent-free hard alloy green bodies with the porosity being 25%-40% are formed under the condition that the temperature of 550-750 DEG C is kept for 2-4 h; core / shell structure powder with Al2O3 covering TiH2 and nanometer graphite with the thickness granularity being 30-50 nm are mixed at the weight percentage ratio of 1:2 so as to prepare a carburizing medium containing hydrogen; the green bodies are embedded into the carburizing medium containing hydrogen and are compacted at the pressure of 5-15 MPa; and finally, liquid-phase sintering is conducted, and in-situ preparation of the hard alloy achieving surface self-lubrication is achieved based on carbon migration. The in-situ preparation method of the hard alloy achieving surface self-lubrication overcomes the problems that in the prior art, grains grow severely, the carburizing time is long and efficiency is low, and in-situ preparation of the hard alloy achieving surface self-lubrication is achieved in the sintering process.

Description

technical field [0001] The invention relates to a preparation method of hard alloy, in particular to an in-situ preparation method of surface self-lubricating hard alloy, which belongs to the field of hard materials. Background technique [0002] Cemented carbide, known as the "teeth" of industry, has a history of more than 80 years since it came out in 1923. For more than 80 years, as a high-efficiency tool material and structural material, cemented carbide has continuously expanded its application fields, played an important role in promoting the world's industrial development and scientific and technological progress, and its market capacity has also continued to expand. 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] CN104404283A relates to a method for directly adding refractory metals to prepare gradient hard ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C29/08C22C29/06C22C1/05C22C1/10C23C8/64
CPCC22C1/051C22C1/058C22C29/005C22C29/067C22C29/08C23C8/64
Inventor 熊计郭智兴刘俊波
Owner SICHUAN UNIV
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