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A kind of surface carburized gradient cemented carbide preparation method

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

Active Publication Date: 2018-10-02
SICHUAN UNIV
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AI Technical Summary

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 cemented carbide with surface carburization, and proposes to remove the cemented carbide compact first. Forming agent to form a porous green body, and then SiO 2 coated TiH 2 core / shell powder, graphene, BaCO 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 the surface carburized gradient cemented carbide is formed in situ during liquid phase sintering

Method used

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  • A kind of surface carburized gradient cemented carbide preparation method

Examples

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example 1

[0018] Example 1: Prepare the surface carburized gradient cemented carbide according to the following steps:

[0019] (1) Preparation of the release agent cemented carbide green body: Weigh various raw material powder ingredients according to weight percentage, among 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 48 hours, filtered with a 400-mesh screen, dried at 90°C, mixed with butadiene rubber molding agent according to 60% of the weight of the cemented carbide powder, and pressed under a pressure of 320MPa to obtain a cemented carbide green body; cemented carbide raw The blank is kept in a vacuum sintering furnace at 620°C for 2 hours, the heating rate is 2°C / min, and the vacuum degree is 12Pa, forming a cemented carbide green body with a porosity of 28% and the removal of the forming agent;

[0020] (2) Preparation of hydrogen-containing carburizing medium: first weigh TiH with...

example 2

[0023] Example 2: Prepare the surface carburized gradient cemented carbide according to the following steps:

[0024] (1) Preparation of the release agent cemented carbide green body: Weigh various raw material powder ingredients according to weight percentage, among which Co accounts for 15wt%, and WC is the balance; mix the weighed powder and pass through 72h ball milling, 400 mesh screen Filtrate, dry at 100°C, mix 100% of the weight of the cemented carbide powder into a butadiene rubber molding agent, press and form under a pressure of 380MPa to obtain a cemented carbide green body; keep the cemented carbide green body at 750°C for 3 hours in a vacuum sintering furnace , the heating rate is 4°C / min, the vacuum degree is 15Pa, and the cemented carbide green body with a porosity of 28% and the removal of the molding agent is formed;

[0025] (2) Preparation of hydrogen-containing carburizing medium: first weigh TiH with a particle size of 0.8 μm 2 The powder is added to abs...

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Abstract

The invention discloses a method for preparing surface carburized gradient cemented carbide, which is characterized in that it first heats the temperature at 550-750°C for 2-4 hours to form a cemented carbide product with a porosity of 25%-40% and removes the forming agent. blank; then SiO2-coated TiH2 core / shell structure powder, graphene with a thickness of less than 3nm, a number of layers less than 3 layers and a specific surface area greater than 250m2 / g, and BaCO3 are prepared by mixing 1:2:1 by weight percentage Hydrogen-containing carburizing medium; then the green body is buried 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-carburized gradient cemented carbide. The invention overcomes the problems of serious grain growth, long carburizing time and low efficiency in the prior art, and prepares surface carburized gradient hard alloy in the sintering process.

Description

technical field [0001] The invention relates to a method for preparing hard alloy, in particular to a method for preparing surface carburized gradient hard alloy, which belongs to the field of hard materials. Background technique [0002] As a new tool material, cemented carbide is based on refractory metal hard compounds (usually referring to carbides, nitrides, borides and silicides of transition elements in the periodic table of elements, etc.), based on iron group Metals (such as cobalt, nickel, iron) are used as bonding metals, which are high hardness and high wear resistance materials manufactured by powder metallurgy. However, it is difficult for homogeneous materials to meet more and more complex working conditions. With the concept of gradient cemented carbide, people pay attention to improving material properties by carburizing the surface. [0003] CN102002664A discloses a preparation method of gradient structure cemented carbide. First, the surface oxidation met...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C29/08C22C1/05C23C8/64B22F3/10
CPCC22C1/051C22C29/08C23C8/64B22F3/1007B22F3/1035B22F2999/00B22F2998/10B22F2201/30B22F2207/01B22F3/1021B22F2201/20B22F1/10B22F3/02
Inventor 郭智兴熊计陈诚
Owner SICHUAN UNIV
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