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Sintering method for ultrafine hard alloy

A technology of cemented carbide and sintering method, applied in the field of alloys, can solve problems such as insufficient grain development, and achieve the effects of excellent comprehensive mechanical properties, improved fracture toughness, improved performance stability and service life

Active Publication Date: 2017-03-22
ZHUZHOU HARD ALLOY GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to develop a sintering method for ultra-fine cemented carbide products. Under the premise that the WC grains in the ultra-fine cemented carbide do not grow sharply, the problem that the grains cannot be fully developed due to the addition of inhibitors can be solved, and the process can be improved. material fracture toughness

Method used

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  • Sintering method for ultrafine hard alloy

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Example 1: The grain size is 0.4 μm, the binder phase is pure cobalt, the mass percentage is 6.5%, the inhibitor is 0.3% VC and 0.4% Cr 2 C 3 Two-step sintering process of cemented carbide compacts.

[0033] WC powder, Co powder, molding agent (paraffin or PEG) and inhibitor are mixed, ball milled, and molded to prepare a compact; the compact is loaded into a pressure sintering furnace, and the 5 Pa hydrogen atmosphere and 380°C dewaxing for 180min; use 15°C / min heating rate, quickly raise the temperature to 1470°C under vacuum condition, keep it for 15min, then use 10°C / min cooling rate to cool down to 1400°C, charge Inject argon to a pressure of 80×10 5 Pa, heat preservation and sintering for 90 minutes, then power off and cool to room temperature with the furnace to obtain ultrafine cemented carbide.

[0034] The performance of the WC (0.4 μm)-6.5wt.% Co product prepared by the two-step sintering method is shown in Table 1, and compared with the one-step sintering...

Embodiment 2

[0038] Example 2: The grain size is 0.4 μm, the binder phase is pure cobalt, the mass percentage is 7%, the inhibitor is 0.3% VC and 0.4% Cr 2 C 3 Two-step sintering process of cemented carbide compacts.

[0039] WC powder, Co powder, molding agent (paraffin or PEG) and inhibitor are mixed, ball milled, and prepared into a compact by extrusion; the compact is loaded into a pressure sintering furnace, and the 5 Pa hydrogen atmosphere and 380°C dewaxing for 180min; use 18°C / min heating rate, quickly heat up to 1480°C under vacuum conditions, keep warm for 12min and then use 12°C / min cooling rate to cool down to 1400°C, fill in Argon to a pressure of 70 x 10 5 Pa, heat preservation and sintering for 80 minutes, then power off and cool to room temperature with the furnace to obtain ultrafine cemented carbide.

[0040] The performance of the WC (0.4 μm)-7wt.% Co product prepared by the two-step sintering method is shown in Table 2, and compared with the one-step sintering (1400°...

Embodiment 3

[0044] Example 3: The grain size is 0.4 μm, the binder phase is pure cobalt, the mass percentage is 8%, the inhibitor is 0.3% VC and 0.4% Cr 2 C 3 Two-step sintering process of cemented carbide compacts.

[0045] WC powder, Co powder, molding agent (paraffin or PEG) and inhibitor are mixed, ball milled, and molded to prepare a compact; the compact is loaded into a pressure sintering furnace, and the 5 Pa hydrogen atmosphere and 380°C dewaxing for 180min; use 20°C / min heating rate, quickly raise the temperature to 1490°C under vacuum conditions, keep warm for 10min and then use 15°C / min cooling rate to cool to 1400°C, fill in Argon to a pressure of 60 x 10 5 Pa, heat preservation and sintering for 60 minutes, then power off and cool to room temperature with the furnace to obtain ultrafine cemented carbide.

[0046] The performance of the WC (0.4 μm)-8wt.% Co product prepared by the two-step sintering method is shown in Table 3, and compared with the one-step sintering (1400 ...

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Abstract

The invention relates to a sintering method for an ultrafine hard alloy. The sintering method comprises the steps that firstly, WC powder, bonding phase powder, a forming agent and an inhibitor are prepared into a press blank; secondly, the forming agent is removed from the press blank in the non-oxidative environment; and thirdly, two-step sintering is conducted on the press blank. In the first step, the temperature is increased to 1,450 DEG C-1,500 DEG C at the temperature rise rate of 10-20 DEG C / min under the vacuum condition, and then heat preservation is conducted; and in the second step, the temperature is reduced to 1,390 DEG C-1,410 DEG C at the cooling rate of 10-15 DEG / min, heat preservation sintering is conducted in the inert atmosphere, and then cooling is conducted. By the adoption of the method, the bending strength and hardness of the ultrafine hard alloy are not reduced but the breaking tenacity of the ultrafine hard alloy is greatly improved; good comprehensive mechanical performance is obtained, the phenomenon of tipping of a small-diameter mini milling cuter is reduced, the performance stability of products can be better improved, and the service life of the products can be better prolonged.

Description

technical field [0001] The invention belongs to the technical field of alloys, and in particular relates to a sintering process of ultrafine cemented carbide products. Background technique [0002] With the rapid development of the global PCB market, the demand for ultra-fine cemented carbide in the field of micro-milling cutters and micro-drills is also increasing, especially to promote the application and development of micro-milling cutters and micro-drills in the direction of small diameters. In order to obtain the high strength and high hardness required by ultra-fine cemented carbide in the application field of small-diameter micro-milling cutters and micro-drills, when preparing alloys, in addition to using WC with small grain size as raw materials, it is also necessary to use WC in the mixture Add inhibitors such as VC and Cr 2 C 3 etc., and use a lower sintering temperature to control the overall grain growth and abnormal growth during the sintering process. Howe...

Claims

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Application Information

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IPC IPC(8): B22F3/10C22C1/05C22C29/08
CPCB22F3/101B22F2999/00C22C1/051C22C29/08B22F2201/013B22F2201/20B22F2201/11
Inventor 刘斌木宗云张卫兵邹能谢英
Owner ZHUZHOU HARD ALLOY GRP CO LTD
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