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Method for improving sintering compactness of un-bonded phase tungsten carbide hard alloy

A cemented carbide and tungsten carbide technology, applied in the field of cemented carbide preparation, can solve the problems of sintering densification, uneven structure and performance, need to keep for several to ten hours, uneven temperature distribution, etc., and achieve dense sintering. The effect of improved performance, small organization and short production cycle

Inactive Publication Date: 2012-03-21
HEFEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, methods such as hot isostatic pressing sintering, ultra-high pressure sintering and rapid hot isostatic pressing sintering, which are improved for the shortcomings of traditional hot pressing sintering, although the sintering temperature and the sintering time are shortened to a certain extent, they usually still require heat preservation. A few to ten hours will inevitably lead to the growth of WC grains
As another example, the spark plasma sintering technology and microwave sintering technology developed in recent years have the advantages of fast heating speed, short sintering time, and uniform heating, so it is easy to obtain materials with uniform and fine grains and high density. The preparation of alloy materials shows better technical advantages than traditional sintering methods, but the above-mentioned technology has uneven temperature distribution, which leads to inhomogeneous sintering densification, structure and performance of the obtained sintered samples

Method used

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  • Method for improving sintering compactness of un-bonded phase tungsten carbide hard alloy
  • Method for improving sintering compactness of un-bonded phase tungsten carbide hard alloy

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] 1. Preparation of activated tungsten carbide powder

[0020] Put the tungsten carbide powder with a particle size of 1-3 microns in the activation solution, ultrasonically activate it for 30 minutes at room temperature, the ultrasonic frequency is 40KHz, and the power is 300-400W. After activation, wash with deionized water three times and dry at 170°C 4 hours to obtain activated tungsten carbide powder;

[0021] Described activation solution is the aqueous solution of hydrofluoric acid, ammonium fluoride and nitric acid, and the concentration of hydrofluoric acid is 30mL / L in the described activation solution, with the hydrofluoric acid solution of mass concentration 40%; The concentration of ammonium fluoride is 10g / L; the concentration of nitric acid is 60mL / L, based on the nitric acid solution with a mass concentration of 65%.

[0022] 2. Molded sintering

[0023] The prepared activated tungsten carbide powder is pressed into shape, and then the vacuum degree is 1...

Embodiment 2

[0026] 1. Preparation of activated tungsten carbide powder

[0027] Put the tungsten carbide powder with a particle size of 1-3 microns in the activation solution, ultrasonically activate it at room temperature for 35 minutes, the ultrasonic frequency is 40KHz, and the power is 300-400W. After the activation is completed, wash with deionized water three times and dry at 150°C 6 hours to obtain activated tungsten carbide powder;

[0028] Described activation solution is the aqueous solution of hydrofluoric acid, ammonium fluoride and nitric acid, and the concentration of hydrofluoric acid is 40mL / L in the described activation solution, with the hydrofluoric acid solution of mass concentration 40%; The concentration of ammonium fluoride is 11g / L; the concentration of nitric acid is 70mL / L, based on the nitric acid solution with a mass concentration of 65%.

[0029] 2. Molded sintering

[0030] The prepared activated tungsten carbide powder is pressed into shape, and then the v...

Embodiment 3

[0033] 1. Preparation of activated tungsten carbide powder

[0034] Put the tungsten carbide powder with a particle size of 1-3 microns in the activation solution, ultrasonically activate it at room temperature for 40 minutes, the ultrasonic frequency is 40KHz, and the power is 300-400W. After the activation is completed, wash with deionized water three times and dry at 180°C 3 hours to obtain activated tungsten carbide powder;

[0035] Described activation solution is the aqueous solution of hydrofluoric acid, ammonium fluoride and nitric acid, and the concentration of hydrofluoric acid is 50mL / L in the described activation solution, with the hydrofluoric acid solution of mass concentration 40%; The concentration of ammonium fluoride is 12g / L; the concentration of nitric acid is 50mL / L, based on the nitric acid solution with a mass concentration of 65%.

[0036] 2. Molded sintering

[0037] The prepared activated tungsten carbide powder is pressed into shape, and then the v...

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Abstract

The invention discloses a method for improving sintering compactness of an un-bonded phase tungsten carbide hard alloy. The method comprises preparation of activated tungsten carbide powder and die pressing sintering, wherein the preparation of the activated tungsten carbide powder comprises the following steps of: putting tungsten carbide powder into an active solution, performing ultrasonic activation treatment for 30 to 40 minutes at normal temperature, washing after the activation is finished, drying for 3 to 6 hours at the temperature of between 150 and 180 DEG C, and thus obtaining the activated tungsten carbide powder, wherein the particle diameter of the tungsten carbide is 1 to 3 microns, and the active solution is an aqueous solution of hydrofluoric acid, ammonium fluoride and nitric acid. According to the method, the sintering compactness of the un-bonded phase tungsten carbide hard alloy can be improved by the activation treatment, the prepared un-bonded phase tungsten carbide hard alloy is small in tissues, the hardness of the alloy is HV1900-2200, and the fracture toughness of the alloy is 7-12MPam<1 / 2>.

Description

1. Technical field [0001] The invention relates to a preparation method of cemented carbide, in particular to a method for improving the sintered compactness of tungsten carbide cemented carbide without binder phase. 2. Background technology [0002] Tungsten carbide (WC) cemented carbide has been widely used in metal cutting, mold, mining and wear-resistant parts and other fields due to its high hardness, high wear resistance and good high temperature strength. Among WC cemented carbides, WC-Co alloys are the most widely studied and applied, but the addition of Co and other binder phases not only reduces the hardness, wear resistance and high-temperature performance of cemented carbide materials, but it is difficult to meet the requirements of corrosive media and high temperature. Harsh conditions such as the environment have strict requirements on its performance; at the same time, because metal Co belongs to the national strategic resource, its further application is limi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C1/04C22C29/08
Inventor 罗来马吴玉程程继贵
Owner HEFEI UNIV OF TECH
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