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A method for preparing superhard cemented carbide rods using wc-co composite powder as raw material by dry bag isostatic pressing and low pressure sintering

A composite powder and low-pressure sintering technology, which is applied in the field of preparation of superhard cemented carbide rods, can solve the problems of reducing the strength and density of the alloy, the impossibility of completely removing the forming agent, and affecting the quality of the cemented carbide. Internal stress, preventing incomplete removal, and reducing the effect of processing aging

Active Publication Date: 2019-10-25
HEFEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It can be seen that in the traditional process of wet grinding and mixing and drying with volatile alcohol, wet grinding is prone to lattice distortion, material fouling, and uneven mixing, which makes the alloy easy to form uneven growth, cobalt pools, thickening, etc. Defects: The granulation process of mixing molding agents (paraffin, PEG, butadiene rubber, cellulose) is mainly to enhance the viscosity of powder particles and facilitate compression molding. At present, most processes use low-temperature sintering and inert gas to remove molding agents, but molding agents are impossible. Completely excluded, some trace impurities will remain, resulting in residual holes in the prepared cemented carbide, reducing the strength and density of the alloy
At the same time, the residual carbon in the forming agent or the carbon in the stripping agent consumes the carbon in the material, which affects the quality of the prepared cemented carbide, leads to decarburization or carburization of the alloy, and affects the performance of the alloy.
[0006] At present, there is no report on the rapid preparation of superhard cemented carbide using dry bag isostatic pressing + low pressure sintering process using WC-Co composite powder as raw material

Method used

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  • A method for preparing superhard cemented carbide rods using wc-co composite powder as raw material by dry bag isostatic pressing and low pressure sintering
  • A method for preparing superhard cemented carbide rods using wc-co composite powder as raw material by dry bag isostatic pressing and low pressure sintering
  • A method for preparing superhard cemented carbide rods using wc-co composite powder as raw material by dry bag isostatic pressing and low pressure sintering

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] 1) Dry bag isostatic pressing:

[0038] 2.53 kg of nano-WC-6Co composite powder with a Co mass content of 6% purchased from Anhui Rongda Composite Powder Technology Co., Ltd. was put into the cavity mold. permanent polyurethane; beat and vibrate the powder loaded into the mold, and cover with the upper cover plate; then use the process of five-stage pressurization and three-stage pressure relief to press and form to obtain a pressed blank;

[0039] The five-stage pressurization process is as follows: the first stage of pressing pressure is 300bar, the pressurization time is 10s, and the pressure holding time is 5s; 20s, holding pressure 15s; the fourth stage pressing pressure 1000bar, pressing time 40s, holding pressure 20s; fifth stage pressing pressure 1200bar, pressing time 60s, holding pressure 60s.

[0040]The three-stage pressure relief process is as follows: the first stage is to release pressure to 800bar, the pressure relief time is 30s, and the pressure is ma...

Embodiment 2

[0056] 1) Dry bag isostatic pressing:

[0057] Put 2.25 kg of nano-WC-8.5Co composite powder with a Co mass content of 8.5% purchased from Anhui Rongda Composite Powder Technology Co., Ltd. into the cavity mold. The mold size is Φ8.2×370mm in diameter, and the mold material is Modified polyurethane; beat and vibrate the powder loaded into the mold, and cover it with a cover plate; then press molding by five-stage pressurization and three-stage pressure relief to obtain a pressed blank;

[0058] The five-stage pressurization process is as follows: the first stage of pressing pressure is 300bar, the pressurization time is 10s, and the pressure holding time is 5s; 20s, holding pressure 15s; the fourth stage pressing pressure 1000bar, pressing time 40s, holding pressure 20s; fifth stage pressing pressure 1200bar, pressing time 60s, holding pressure 60s.

[0059] The three-stage pressure relief process is as follows: the first stage is to release pressure to 800bar, the pressure r...

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Abstract

The invention discloses a method of preparing a superhard alloy bar by using WC-Co composite powder as a raw material through dry bag isostatic pressing and low-pressure sintering. The method is characterized in that the nanometer WC-Co composite powder is used as a raw material, firstly the raw material is put in a dry bag isostatic pressing equipment mold cavity so as to suffer compression molding, and then low-pressure sintering furnace equipment is used for sintering so as to obtain the superhard alloy bar. The method has the beneficial effects that working procedures such as material mixing by wet milling, drying by alcohol volatilization, granulation by blending a forming agent and pressed blank drying in the process of preparing the superhard alloy bar by using low-Co fine-crystalline grain WC as raw materials are omitted, the technological process is short, the equipment operation is simple, and large-sized long bars can be produced.

Description

technical field [0001] The invention relates to a method for preparing superhard cemented carbide rods. The superhard cemented carbide rods prepared by the method are processed into non-standard drill bits or milling cutters, which are used for special tools in the automobile industry. Background technique [0002] The automobile industry is the industry with the most application of special tools, and it is also a symbol to measure the technical level of a country or a tool company. Most of my country's automobile production lines (especially car production lines) are imported from abroad, and cutting tools are mainly imported together with the equipment. At present, domestic automobile production lines include American, European, Japanese and Korean models, as well as independent models mainly based on European equipment. There are five major knife factions active in China: one is Sandvik (including Seco), Sandvik has a large and complex branch of knives, and has the large...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F3/04B22F3/14C22C1/05C22C29/08
CPCB22F3/04B22F3/14B22F3/24B22F2003/247C22C1/051C22C29/005C22C29/08
Inventor 朱二涛张久兴杨新宇
Owner HEFEI UNIV OF TECH
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