Method for surface boriding of hard alloy

A technology of hard alloy and treatment method, which is applied in the direction of metal material coating process, coating, solid-state diffusion coating, etc., and can solve problems such as difficult boronizing treatment of blanks

Active Publication Date: 2011-01-19
ZHUZHOU HARD ALLOY GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] At present, vacuum sintering is generally used in the preparation of cemented carbide, and the sintering process is rarely used to protect the sintering process. It is difficult to boronize the sintered blank.

Method used

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  • Method for surface boriding of hard alloy
  • Method for surface boriding of hard alloy
  • Method for surface boriding of hard alloy

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] For long carbide samples (5.25×6.5×20mm, the following samples have the same shape and size) with Co weight percentages of 6%, 11%, and 15% to be boronized, use a silicon nitride grinding wheel to remove the surface oxide layer; Solid boronizing agent, the weight percentage of each component is: 39%B 4 C. 10%KBF 4 , 7% rare earth oxide, 1% Mg powder, 5% ammonium carbonate, 24% graphite particles, 14% SiC.

[0024]Embed the above-mentioned cemented carbide to be boronized in the boronizing agent, and at the same time embed the wear-resistant sample (32×18×7mm, the same shape and size of the following wear-resistant samples) in the boronizing agent, and place it in the threaded sealing cover In the graphite jar, screw the lid tightly and put it into the induction heating furnace. Close the lid of the induction furnace and vacuumize. When the vacuum reaches 100Pa or more, turn off the vacuum unit, feed nitrogen to 0.07MPa, and start heating. The boronizing temperature ...

Embodiment 2

[0027] Use diamond grinding wheel to grind the hard alloy strip sample to be boronized with 6% and 11% by weight of Co to remove the surface oxide layer; prepare a solid boronizing agent, and the weight percentage of each component is: 13%BN, 20% %B 4 C, 1% amorphous boron, 7% NH 4 BF 4 , 3% rare earth oxide, 1% Mg powder, 34% graphite particles, 21% Al 2 o 3 pink.

[0028] The above-mentioned cemented carbide and wear-resistant samples to be boronized are buried in the boronizing agent, placed in a graphite tank with a threaded sealing cover, tightened the cover, and placed in an induction heating furnace. Close the furnace cover of the induction furnace and vacuumize it. When the vacuum reaches 100Pa or more, close the vacuum unit and feed the flowing H 2 Gas, keep the gas pressure in the furnace positive, and start heating. The boronizing temperature is 900°C and the temperature is kept for 5 hours. At boronizing temperature, the NH in the activator 4 BF 4 The gas...

Embodiment 3

[0031] For the cemented carbide button sample to be boronized with a Co weight percentage of 15%, use sandblasting to remove the surface oxide layer; prepare a solid boronizing agent, and the weight percentage of each component is: 5%B 4 C. 7%KBF 4 , 3% rare earth oxide, 10% graphite particles, 75% SiC.

[0032] The above-mentioned cemented carbide and wear-resistant samples to be boronized are buried in the boronizing agent, placed in a graphite tank with a threaded sealing cover, tightened the cover, and placed in an induction heating furnace. Close the induction furnace cover and vacuumize. When the vacuum reaches 100Pa or more, turn off the vacuum unit, feed Ar gas to 0.07MPa, and start heating. The boronizing temperature is 1000°C and the temperature is kept for 5 hours. At boronizing temperature, KBF in activator 4 The gas produced by decomposition, and part of the solid boron donor B 4 C reacts to form B atoms, carried by the aforementioned unreacted decomposition ...

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Abstract

The invention discloses a new method for surface boriding of hard alloy, which sequentially comprises the following steps of: removing an oxidation layer on the surface of the hard alloy; embedding the hard alloy into a solid boriding agent, putting the mixture into a nearly-closed boriding container, and putting the container into an induction heating furnace; vacuumizing the furnace, stopping vacuumizing until the vacuity is over 100 Pa, and filling inert gas or hydrogen; after the gas in the furnace reach the pressure, starting to perform induction heating to reach the boriding temperature of between 800 and 1,300 DEG C, and performing heat preservation for 0.5 to 8 hours to realize gas-solid phase boriding. The solid boriding agent comprises the following components in percentage by weight: 5 to 50 percent of boron supply agent, 2 to 40 percent of activating agent and the balance of fillers, wherein the boron supply agent is one or more of powdered B4C, BN and amorphous boron; the activating agent is two or more of powdered KBF4, NaBF4, NH4BF4, (NH4)2CO3, rare earth oxide and Mg powder, and one of the mixture is an activating agent containing a B element; and the filler consists of graphite powder granules and SiC powder or Al2O3 powder. Through the method, the boriding thickness of sintered hard alloy blank is more than 0.1 millimeter and is close to 1 millimeter, so the surface abrasion resistance of the hard alloy is improved greatly.

Description

technical field [0001] The invention belongs to the field of surface treatment, and carries out surface boronizing treatment on cemented carbide including cutting tools, wire drawing dies, cemented carbide for rock drilling and wear-resistant parts, to form a surface wear-resistant layer and improve its wear resistance. Background technique [0002] Cemented carbide is generally sintered from WC and Co. It has high hardness, bending strength and wear resistance, and is widely used as wear-resistant parts, such as cutting tools in the machining industry, oil drilling, and mining drill bits. Alloy teeth, wire drawing dies in the material processing industry, etc. Surface treatment of cemented carbide to further improve its wear resistance, in recent years, various related enterprises and institutes have carried out extensive research, such as coating technology, boronizing technology, etc. However, chemical vapor deposition in the coating technology has an obvious bonding int...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C8/68
Inventor 林国标邱智海张忠健徐涛邓涛
Owner ZHUZHOU HARD ALLOY GRP CO LTD
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