Method for preparing ultra-fine crystal WC-Co hard alloy

A cemented carbide and ultra-fine grain technology, which is applied in the field of high-performance functional materials to achieve the effects of high hardness, small grain size and broad application prospects.

Inactive Publication Date: 2008-01-16
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At home and abroad, there is no report on the preparation of ultra-fine WC-C

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0016] Example 1:

[0017] Raw materials: the mass ratio of WC powder with a particle size of 0.2 μm, pure Co powder and VC powder with a particle size of 2.94 μm is 88.7:11:0.3.

[0018] Take the raw material powder of the above ratio and mix it evenly by high-energy ball milling for 30 minutes. After drying, it is put into a graphite mold for hot pressing and sintering. The sintering process is: heating at a heating rate of 50°C / min, applying a pressure of 40MPa, and when the temperature When the temperature is raised to 750°C, the temperature is kept for 5 minutes, and the hot pressing is completed. When it is cooled to below 100°C, take it out and demould. Then combine the hot-pressed compact, graphite sealing sheet, carbon steel pressurized sheet, and pyrophyllite sheath that integrates insulation, heat insulation and pressure transmission. The combined sample is placed in a six-sided top press for super Electric sintering under high pressure, the sintering voltage is 1.25V, ...

Example Embodiment

[0019] Example 2:

[0020] Raw materials: WC powder with a particle size of 0.2μm, pure Co powder and Cr with a particle size of 3.6μm 3 C 2 The powder mass ratio is 88.6:11:0.4.

[0021] Take the raw material powder of the above ratio and mix it evenly by high-energy ball milling for 30 minutes. After drying, it is put into a graphite mold for hot pressing and sintering. The sintering process is: heating at a heating rate of 50°C / min, applying a pressure of 40MPa, and when the temperature When the temperature is raised to 750°C, the temperature is kept for 5 minutes, and the hot pressing is completed. When it is cooled to below 100°C, take it out and demould. Then combine the hot-pressed compact, graphite sealing sheet, carbon steel pressurized sheet, and pyrophyllite sheath that integrates insulation, heat insulation and pressure transmission. The combined sample is placed in a six-sided top press for super Electric sintering under high pressure, the sintering voltage is 1.25V, ...

Example Embodiment

[0022] Example 3:

[0023] Raw materials: WC powder with a particle size of 0.5μm, pure Co powder and Cr with a particle size of 3.6μm 3 C 2 The powder mass ratio is 91.6:8:0.6.

[0024] Take the raw material powder of the above ratio and mix it evenly by high-energy ball milling for 30 minutes. After drying, it is put into a graphite mold for hot pressing and sintering. The sintering process is: heating at a heating rate of 50°C / min, applying a pressure of 40MPa, and when the temperature When the temperature is raised to 750°C, the temperature is kept for 5 minutes, and the hot pressing is completed. When it is cooled to below 100°C, take it out and demould. Then combine the hot-pressed compact, graphite sealing sheet, carbon steel pressurized sheet, and pyrophyllite sheath that integrates insulation, heat insulation and pressure transmission. The combined sample is placed in a six-sided top press for super Electric sintering under high pressure, the sintering voltage is 1.4V, th...

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Abstract

A preparation method of superfine crystal WC-Co hard alloys belongs to the field of high-performance functional materials. The powder mixture is composed of 8-11wt percent of Co, 0.001-0.7wt percent of VC, 0.001-0.8wt percent of Cr3C2, and WC with a grain size of 0.2-0.5 micron in balance. The powder mixture is weighed at the given weight ratio and then subjected to alloying treatment under such conditions that the ball-milling time is 15-60 min, the rotational speed of ball mill is 800-1400 r/min-1, the ratio of media-to-material is 5:1 to 10:1; and the level of ball milling media is 5-10 mm above the surface of the ball-milled material, so that the powder mixture is pre-formed to form a pre-forming blank with a density of 50-70 percent. The pre-forming blank is further processed into superfine WC-Co hard alloy by the ultra-high pressure sintering process in a six-face presser, under the following conditions: sintering voltage of 1.25-1.40V, sintering pressure of 10-12GPa, and sintering time of 60-120s. The method has the advantages that the powder is rapidly densified upon an extremely-high pressure and heating simultaneously; and the obtained produce has full density and high hardness (up to 93.1HRA) while the grain size of WC remains almost unchanged.

Description

technical field [0001] The invention belongs to the field of high-performance functional materials, and in particular provides a preparation method of ultra-fine grain WC-Co hard alloy, which can inhibit the growth of WC crystal grains and improve the performance of WC-Co hard alloy. Background technique [0002] WC-Co cemented carbide has special corrosion resistance, high hardness, excellent fracture toughness and compressive strength. It is used in wear-resistant parts and structural components, plungers of high-pressure vessels, hydraulic cylinders, precision rolls, and synthetic diamonds. The top hammer of the steel wire rolling mill, the roll of the steel wire rolling machine, etc., occupy an extremely important position in the fields of machinery, metallurgy, cutting tools, precision instruments, and military industry. In recent years, with the rapid development of electronics, precision machining, medicine, aerospace and other industries, the performance of ordinary ...

Claims

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Application Information

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IPC IPC(8): C22C1/04B22F3/16B22F9/04C22C29/08
Inventor 贾成厂孙兰曹瑞军林晨光
Owner UNIV OF SCI & TECH BEIJING
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