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Process for preparing surface decarbonized WC-Co gradient hard alloy preform

A cemented carbide and preparation process technology, applied in the field of cemented carbide material manufacturing, to achieve the effects of improved comprehensive performance, simple process method, and convenient operation

Active Publication Date: 2011-07-20
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

Conventional WC-Co cemented carbide is composed of two phases of WC phase and binder phase. The internal and external structure and mechanical properties of the product are consistent, and there is a contradiction between high hardness and wear resistance and toughness.

Method used

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  • Process for preparing surface decarbonized WC-Co gradient hard alloy preform
  • Process for preparing surface decarbonized WC-Co gradient hard alloy preform
  • Process for preparing surface decarbonized WC-Co gradient hard alloy preform

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Take the WC-6Co mixture to prepare the surface decarburized WC-Co gradient cemented carbide preform as an example. The mixture is pressed and formed by a two-way press; in a vacuum furnace, it is dewaxed at 150-350 ° C for 100 minutes; After the dewaxing is completed, heat up to 800°C, pre-burn at 800°C for 0.5h, and cool with the furnace; soak the calcined billet in the ammonium metatungstate solution with a mass fraction of 40% for 5min, take it out and place it under vacuum at 80°C Dry for 12 hours; the dried tungsten infiltrated pre-sintered blank is heated from room temperature to 450°C in a vacuum furnace after 3 hours, kept at 450°C for 20 minutes, then heated to 1460°C after 2 hours, sintered at 1460°C for 50 minutes, and finally cooled with the furnace. See attached figure 1 , 2 , metallographic analysis was carried out on the specimen, and the analysis results showed that an obvious decarburization phase was formed in the depth of about 800 μm in the surface ...

Embodiment 2

[0028] Taking WC-6Co mixture to prepare surface decarburized WC-Co gradient cemented carbide preform as an example, the mixture is pressed and formed by a bidirectional press; in a vacuum furnace, it is dewaxed at 200-400 ° C for 100 minutes; After the dewaxing is completed, heat up to 850°C, pre-burn at 850°C for 0.5h, and cool with the furnace; soak the calcined billet in the ammonium metatungstate solution with a mass fraction of 50% for 15min, take it out and place it under vacuum at 100°C Dry for 12 hours; the dried tungsten infiltrated pre-sintered billet is heated from room temperature to 450°C in a vacuum furnace after 3 hours, kept at 450°C for 30 minutes, then heated to 1440°C after 3 hours, sintered at 1440°C for 80 minutes, and finally cooled with the furnace. See attached image 3 , Metallographic analysis was carried out on the test piece, and the analysis results showed that an obvious decarburization phase was formed in the depth of about 1100 μm in the surface...

Embodiment 3

[0030] Take the WC-8Co mixture to prepare the surface decarburized WC-Co gradient cemented carbide preform as an example. The mixture is pressed and formed by a two-way press; in a vacuum furnace, it is dewaxed at 300-500 ° C for 100 minutes; After the dewaxing is completed, heat up to 900°C, pre-burn at 900°C for 0.5h, and cool with the furnace; soak the calcined billet in the ammonium metatungstate solution with a mass fraction of 60% for 25min, take it out and put it under vacuum at 100°C Dry for 12 hours; the dried tungsten infiltrated pre-sintered blank is heated from room temperature to 450°C in a vacuum furnace after 3 hours, kept at 450°C for 40 minutes, then heated to 1420°C after 4 hours, sintered at 1420°C for 90 minutes, and finally cooled with the furnace. See attached Figure 4 , 5 , Metallographic analysis was carried out on the test piece, and the analysis results showed that the surface layer of the sample was seriously decarburized, while the core was less d...

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Abstract

The invention discloses a process for preparing a surface decarbonized WC-Co gradient hard alloy preform, which comprises the following steps of: dewaxing and pre-sintering the conventional WC-Co hard alloy compact, soaking in solution of ammonium paratungstate, drying, and sintering in a vacuum furnace to prepare the surface decarbonized WC-Co gradient hard alloy perform. The process concretely comprises the following steps of: dewaxing and pre-sintering the normal WC-Co hard alloy compact to obtain a pre-sintered blank with certain strength and porosity; soaking in the solution of ammonium paratungstate and distributing the ammonium paratungstate in certain depth and concentration gradient from the surface to the interior; and drying, sintering a sample in the vacuum furnace, slowly raising the temperature in a low temperature stage to decompose the ammonium paratungstate, and reacting the decomposed product (oxide of tungsten) with the WC and Co on the surface to prepare the surface decarbonized WC-Co gradient hard alloy perform. The process method is simple, and convenient to operate; the prepared surface decarbonized WC-Co gradient hard alloy preform provides possibility of improving the comprehensive performance of hard alloys; and the process is suitable for industrial production.

Description

technical field [0001] The invention discloses a preparation process of a surface-layer decarburized WC-Co gradient cemented carbide prefabricated body. 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 has important applications in metal cutting, wood processing, oil and mining drilling, composite material processing, etc. . Conventional WC-Co cemented carbide is composed of two phases of WC phase and binder phase. The internal and external structure and mechanical properties of the product are consistent, and there is a contradi...

Claims

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Application Information

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IPC IPC(8): B22F3/16B22F3/26C22C29/08C22C1/05
Inventor 刘咏李亚林李昆
Owner 株洲金韦硬质合金有限公司
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