High-ductility, corrosion-resistant and ultra/extra-thick crystalline cemented carbide and preparation method thereof

A cemented carbide, corrosion-resistant technology, applied in the field of powder metallurgy materials, can solve problems such as reducing the fracture toughness of alloys, and achieve the effect of good acid/alkali resistance and oxidation corrosion resistance

Inactive Publication Date: 2012-10-17
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The study found that the addition of VC to WC–Co cemented carbide significantly reduces the fracture toughness of the alloy

Method used

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  • High-ductility, corrosion-resistant and ultra/extra-thick crystalline cemented carbide and preparation method thereof
  • High-ductility, corrosion-resistant and ultra/extra-thick crystalline cemented carbide and preparation method thereof
  • High-ductility, corrosion-resistant and ultra/extra-thick crystalline cemented carbide and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Using WC powder with a grain size of 7 μm and Cr with a Fischer grain size of 1.02 μm 3 C 2 powder as raw material, according to the mass fraction of WC-8%Co-0.4%Cr 3 C 2 (1# alloy) composition ratio, using stirring method to make the containing WC and Cr 3 C 2 The raw material powder is suspended in the cobalt hydroxide alkaline slurry with an initial pH value of 10.5, and the cobalt hydroxide alkaline slurry is reduced at 150°C for 8 hours under a hydrogen pressure of 4.5MPa to prepare a nano-assembly structure Co-coated WC Compound powder. Then, in a hydrogen atmosphere at 650 °C, the nano-assembled Co-coated WC composite powder was subjected to diffusion homogenization and Co-coated densification to form Co densely coated WC composite powder. Then, 2.0% PEG forming agent was added to the Co densely coated WC composite powder, and the composite powder mixed with the forming agent was dried and granulated. Liquid phase sintering was carried out at 1430°C in a pr...

Embodiment 2

[0024] Using WC powder with a grain size of 7 μm and Cr with a Fischer grain size of 1.02 μm 3 C 2 powder and La with a specific surface area average diameter of 73.1nm 2 o 3 Powder is the raw material, according to the mass fraction, it is WC-8%Co-0.4%Cr 3 C 2 -0.048%La 2 o 3 (2# alloy) composition ratio, using stirring method to make the containing WC, Cr 3 C 2 and La 2 o 3 The raw material powder is suspended in the cobalt hydroxide alkaline slurry with an initial pH value of 11.5, and the cobalt hydroxide alkaline slurry is reduced at 180°C for 2 hours under a hydrogen pressure of 2.5MPa to prepare a nano-assembly structure Co-coated WC Compound powder. Then, in a hydrogen atmosphere at 600 °C, the nano-assembled Co-coated WC composite powder was subjected to diffusion homogenization and Co-coated densification to form a Co densely coated WC composite powder. Then, a paraffin wax forming agent accounting for 2.5% of the total mass fraction of the composite powde...

Embodiment 3

[0026] Using WC powder with a grain size of 7 μm and Cr with a Fischer grain size of 1.02 μm 3 C 2 Rare earth (RE)-Co pre-alloyed powder of -200 mesh, containing 65% Co with a mass fraction of Co of 65% as raw materials, according to the mass fraction of WC-8%Co-0.4% Cr 3 C 2 – 0.048% RE (3# alloy) composition ratio, using stirring method to make the containing WC, Cr 3 C 2 and RE–Co pre-alloyed powders were suspended in cobalt hydroxide aqueous slurry with initial pH value of 11.5, hydrazine hydrate N 2 h 4 ·H 2 O is the reducing agent, select N 2 h 4 ·H 2 O:Co 2+ The molar ratio of the cobalt hydroxide is 3:1, and the cobalt hydroxide aqueous slurry is reduced at 60 °C under normal pressure to prepare a nano-assembly structure Co-coated WC type composite powder. Then, in a hydrogen atmosphere at 700 °C, the nano-assembly structure Co-coated WC composite powder was diffused and homogenized, and the Co coating was densified to form a Co densely coated WC composite p...

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Abstract

The invention discloses a high-ductility, corrosion-resistant and ultra/extra-thick crystalline cemented carbide and a preparation method thereof. By taking Coarse WC (wolfram carbide) powder as raw materials, and through separately adding Cr3C2 or adding Cr3C2 and rare earth in a combined mode, and adopting a Co/Ni densely-cladded WC-type composite powder process, ultra/extra-thick crystalline cemented carbides with high ductility and better acid/alkali-resistance and oxidation/corrosion resistance are prepared. The adding amounts of the Cr3C2 and the rare earth are respectively 5-8% and 0.4-0.6% of the total mass fraction of Co/Ni in the cemented carbide. The rare earth can be added in rare earth-cobalt pre-alloyed powder form or in oxide form, and when the rare earth is added in oxide form, the adding amount is calculated by oxides. The composite powder process refers to prepare nano assembling structured Co/Ni densely-cladded WC-type composite powder by using a hydrothermal high pressure hydrogen reduction or hydrazine hydrate aqueous-phase normal-pressure reduction process, and then carry out thermal diffusion homogenization and Co/Ni cladded densification processing on the composite powder in a hydrogen atmosphere by using a nano diffusion sintering effect.

Description

technical field [0001] The present invention relates to a kind of cemented carbide and its preparation method, in particular to a super-coarse-grained hard alloy with high toughness, better acid / alkali resistance and oxidation corrosion resistance and its preparation method, belonging to powder metallurgy materials field. Background technique [0002] According to the cemented carbide classification standard of Sandvik, the most internationally influential cemented carbide manufacturer, cemented carbides with a WC grain size of 3.5 μm to 4.9 μm, 5.0 μm to 7.9 μm, and 8.0 μm to 14 μm are respectively It is coarse-grained, ultra-coarse-grained and extra-coarse-grained cemented carbide. In terms of mass fraction, the content of binder metal in cemented carbide is usually between 3% and 30%. Under the condition of the same binder metal content, compared with traditional medium and coarse-grained cemented carbides, ultra-coarse-grained and extra-coarse-grained cemented carbides...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C29/08C22C1/05B22F1/02
Inventor 张立吴厚平陈述雷霆熊湘君
Owner CENT SOUTH UNIV
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