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Method for preparing coarse grain hard alloy

A cemented carbide and coarse-grained technology, which is applied in the field of coarse-grained WC-Co cemented carbide and its preparation, can solve the problem of poor resistance to thermal shock and thermal plastic deformation, poor matching of strength and microhardness , Alloy high temperature strength is not high, etc., to improve the ability of thermal shock resistance and thermal plastic deformation resistance, small micro-strain, improve the overall performance of the alloy

Inactive Publication Date: 2008-02-13
ZHUZHOU HARD ALLOY GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The ordinary coarse-grained WC belongs to polycrystalline agglomeration, and the vacuum sintering temperature is less than or equal to 1450°C. The bending strength of the coarse-grained cemented carbide prepared by this method is 1840-2800MPa, and the hardness Hv 30 1150~1330, the matching between strength and microhardness is poor, and the comprehensive performance is low, especially the high temperature strength of the alloy is not high, the resistance to thermal shock and thermal plastic deformation is not strong, it is not suitable for working in high temperature environment, which greatly limits The scope of application of the alloy

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0008] Example 1: Co powder with a weight percentage of 8.0% and TaC powder with 0.4% are selected when compounding. The balance is a coarse-grained WC powder with a Fsss particle size of 13.0 μm and an Hcp value of 4.50-4.62KA / m, which is close to single crystal. Where TaC:Co=0.05. Alcohol was used as the ball milling medium, the liquid-to-solid ratio was 205ml / Kg, the ball-to-battery ratio was 2.72:1, and the ball milling time was 26 hours. The mixture was dried and molded, and then placed in a vacuum sintering furnace at 1520°C for sintering. The PS21 (size 6.5×5.25×20mm) sample strip is used as the standard product for testing the ultrafine cemented carbide prepared by the method of the present invention (the following examples are the same), the average grain size of WC is 3.2μm, and the bending strength is 2600MPa, hardness Hv 30 1250~1320.

Embodiment 2

[0009] Example 2: Co powder with a weight percentage of 9.5% and TaC powder with a weight percentage of 0.45% are selected for the ingredients, and the balance is a coarse-grained WC powder with a Fsss particle size of 15.0μm and an Hcp value of 4.50~4.58KA / m, which is close to single crystal. Wherein TaC:Co=0.473. Alcohol was used as the ball milling medium, the liquid-to-solid ratio was 205ml / Kg, the ball-to-battery ratio was 3.4:1, and the ball milling time was 24 hours. The mixture was dried and molded, and then placed in a vacuum sintering furnace at 1490°C for sintering. The average WC grain size of the product is 3.8μm, the bending strength is 2950MPa, and the hardness is Hv 30 1150~1220.

Embodiment 3

[0010] Example 3: Co powder with a weight percentage of 10.2% and TaC powder with 0.5% are selected for compounding. The balance is a coarse-grained WC powder with a Fsss particle size of 15.0μm and an Hcp value of 4.59~4.74KA / m, which is close to single crystal. Wherein TaC:Co=0.049. Alcohol was used as the ball milling medium, the liquid-to-solid ratio was 200ml / Kg, the ball-to-battery ratio was 2.72:1, and the ball milling time was 20 hours. The mixture was dried and molded, and then placed in a vacuum sintering furnace at 1450°C for sintering. The average WC grain size of the product is 3.8μm, the bending strength is 3020MPa, and the hardness is Hv 30 1140~1230.

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Abstract

The invention provides a coarse-grained hard alloy and a preparation method of the coarse-grained hard alloy, which mainly includes WC, Co accounting for 8.0 to 11.5 weight percent and TaC accounting for 0.4 to 0.6 weight percent; the average grain size of the WC in the coarse-grained hard alloy is 3.2 to 4.0Mu m, and the bending resistance strength is 2600 to 3100 MPa and the hardness Hv30 is 1100 to 1320. The preparation materials adopt the coarse-grained WC powder close to single crystal, with Fsss size 11.0 to 15.0Mu m and Hcp value 4.50 to 5.38 KA / m, TaC powder and Co powder; the vacuum sintering temperature is 1450 to 1520 DEG C, the ratio of TaC to Co is equal to to 0.045 to 0.055. The invention well matches the alloy strength and micro-harness, improves the over-all performance, thermal shock resistance and thermal plastic deformation resistance of the coarse-grained hard alloy.

Description

Technical field [0001] The invention relates to a hard alloy and a preparation method thereof, in particular to a coarse-grained WC-Co hard alloy and a preparation method thereof. Background technique [0002] Cemented carbide has a wide range of uses due to its high hardness and high strength. In the past, the materials commonly used in the manufacture of mining rock drilling tools and sand making machine alloy sheets in China are generally ordinary coarse-grained WC powder with a Fischer particle size of 11.0-25.0μm and Co powder with a weight percentage of 8% to 11.5%, after wet grinding , Drying, compression molding and vacuum sintering process. The ordinary coarse-grained WC belongs to polycrystalline agglomeration, and the vacuum sintering temperature is less than or equal to 1450°C. The flexural strength of the coarse-grained cemented carbide prepared by this method is 1840-2800MPa, and the hardness is Hv 30 1150~1330, poor matching of strength and microhardness, low compr...

Claims

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Application Information

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IPC IPC(8): C22C29/08C22C1/05B22F9/04B22F3/16
Inventor 周悫昱陈妍
Owner ZHUZHOU HARD ALLOY GRP CO LTD
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