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Preparation technology of hard alloy with gradiently-changed cobalt content at surface layer

A cemented carbide, gradient change technology, applied in the direction of metal material coating process, coating, solid-state diffusion coating, etc., can solve the problems of affecting the performance of materials, and achieve improved service life, high hardness and wear resistance Performance, the effect of improving mechanical properties and service life

Active Publication Date: 2012-07-25
株洲金韦硬质合金有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the cemented carbide prepared by this method has a gradient change in cobalt content, the inner layer of the material contains a hard and brittle η phase, which will inevitably affect the performance of the material.

Method used

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  • Preparation technology of hard alloy with gradiently-changed cobalt content at surface layer
  • Preparation technology of hard alloy with gradiently-changed cobalt content at surface layer
  • Preparation technology of hard alloy with gradiently-changed cobalt content at surface layer

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Taking YG10 standard cemented carbide as the sample, add 7 times ammonium paratungstate to the 4% polyvinyl alcohol solution to prepare a viscous paste; evenly coat the prepared paste on the YG10 standard cemented carbide test sample. to form a coating of about 1-2mm on the surface of the sample, and dry it for use; pre-fire the dried sample in a hydrogen atmosphere at 900°C for 0.5h, then push the boat to a high temperature zone of 1450°C for 1h, and then take it out of the oven and place it in a hydrogen atmosphere Then, the precursor sample was embedded in carbon black filler, and carburized in a hydrogen atmosphere at 1450°C for 1h. The obtained product is tested by metallographic structure and SEM, and it is found that the cobalt content of the surface layer is a cemented carbide precursor with a gradient change, and a relatively uniform decarburized structure appears on the surface layer. figure 1 shown; and the cemented carbide after carburizing (attached figur...

Embodiment 2

[0027] Taking YG10 standard cemented carbide as the sample, add 6 times ammonium paratungstate to the 2% polyvinyl alcohol solution to prepare a viscous paste; evenly coat the prepared paste on the YG10 standard cemented carbide test sample. to form a coating of about 1-2mm on the surface of the sample, and dry it for use; pre-fire the dried sample in a hydrogen atmosphere at 800°C for 0.5h, then push the boat to a high temperature zone of 1420°C for 2h, and then take it out of the furnace and place it in hydrogen Cool in the atmosphere to obtain a cemented carbide precursor with a gradient change in cobalt content on the surface; then the precursor sample is embedded in carbon black filler, and carburized in a hydrogen atmosphere at 1450 ° C for 1 hour. The obtained product is tested by metallographic structure and SEM. The hardness test shows that the average hardness of the surface layer is about 1600HV, the middle layer is 1300HV, and the inner layer hardness is 1450HV. Af...

Embodiment 3

[0029] Taking YG10 standard cemented carbide as the sample, add 6 times ammonium paratungstate to the 3% polyvinyl alcohol solution to prepare a viscous paste; evenly coat the prepared paste on the YG10 standard cemented carbide test sample. to form a coating of about 1-2 mm on the surface of the sample, and dry it for use; pre-fire the dried sample in a hydrogen atmosphere at 800 ° C for 0.5 h, then push the boat to a high temperature zone of 1450 ° C for 1 h, and cool it to liquid with the furnace After it is below the phase line, it is taken out of the furnace and cooled in a hydrogen atmosphere to obtain a cemented carbide precursor with a gradient change in cobalt content on the surface; then, the precursor is embedded in a carbon black filler and carburized in a hydrogen atmosphere at 1450°C 1h. The obtained product is detected by metallographic structure and SEM, and it is found that the cobalt content of the surface layer is a cemented carbide precursor with a gradient...

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Abstract

The invention discloses a preparation technology of a hard alloy with gradiently-changed cobalt content at a surface layer. The method comprises the steps of firstly, preparing a hard alloy which is decarbonized at a surface layer and has normal phase at a core by permeating the tungsten by the means that the normal hard alloy is protected by hydrogen atmosphere; and secondly, carburizing hard alloy under the protection of the hydrogen to obtain the hard alloy with gradiently-distributed cobalt content. The technology comprises the steps of firstly preparing the hard alloy which is decarbonized at the surface layer; forming the cobalt phase gradient on the surface layer of the hard alloy and leading the core to keep the normal hard alloy structure due to the reasons such as the reaction diffusion, the liquid phase flow and the like to obtain a product with good mechanical property. As the hard alloy which is decarbonized at the surface layer is only prepared, compared with the method for normally preparing the hard alloy with a gradient structure, the core of the hard alloy has the normal alloy tissue after permeating the carbon, the preparation technology has better mechanical property and processing property compared with the normal method, and is better in application prospect.

Description

technical field [0001] The invention discloses a preparation process of a cemented carbide whose cobalt content in the surface layer changes gradually. The invention belongs to the technical field of hard alloy material manufacturing. Background technique [0002] Cemented carbide is a kind of cermet tool material prepared by powder metallurgy with refractory metal compounds (WC, TaC, TiC, NbC, etc.) as the matrix and transition metals (Co, Fe and Ni) as the binder phase. . Due to its high strength, high hardness, high elastic modulus, wear resistance, corrosion resistance, small thermal expansion coefficient and stable chemical properties, it is widely used in metal cutting tools. There are important applications in wood processing cutting tools, oil and mining drilling tools, composite material processing tools, cold forming tools, wear-resistant parts and hot rolling rolls. [0003] Conventional WC-Co hard alloy blades, drill teeth, rock cutting and wire drawing dies h...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C29/08C23C10/30C23C8/64
Inventor 刘咏李昆李亚林李荣付
Owner 株洲金韦硬质合金有限公司