A method for increasing the carbon potential of low-carbon cemented carbide

Abstract

A method for improving carbon potential of a low-carbon hard alloy is characterized in that gas carbonizing treatment is carried out on the low-carbon hard alloy, wherein gas carbonizing treatment comprises the following steps that firstly, the low-carbon hard alloy is arranged in a sintering furnace, the room temperature is raised to 1,340 DEG C to 1,400 DEG C, then, the temperature is kept for 30-180 min, during the temperature keeping time, mixed gas of H2 and CH4 is introduced into the sintering furnace in a pulse manner, low pressure is adopted after high pressure is adopted, the high pressure ranges from 200 mbar to 800 mbar, and the lower pressure ranges from 10 mbar to 50 mbar; moreover, the pulse period ranges from 5 min to 10 min, the time ratio of the high-pressure stage to the low-pressure stage ranges from 2: 1 to 4: 1; secondly, the low-carbon hard alloy is cooled to 1,270 DEG C to 1,330 DEG C, then, the temperature is kept for 30 min to 180 min, and during the temperature keeping time, inert gas with the pressure ranging from 1,000 mbar to 2,000 mbar is introduced into the sintering furnace; and thirdly, the low-carbon hard alloy is cooled to the room temperature, and the product is taken out of the furnace.

Description

technical field [0001] The invention relates to a method for increasing the carbon potential (magnetic saturation) of cemented carbide products, which is used for improving the magnetic saturation of products such as cemented carbide studs used in geological exploration, rock drilling, coal digging, and mine development. Background technique [0002] Low-cobalt WC-Co cemented carbide emphasizes toughness during use, and its magnetic saturation should be controlled above 135 emu / g-160emu / g. Due to the narrow WC-γ two-phase region of low-cobalt WC-Co cemented carbide (below 8% Co), there is a problem that the carbon balance is difficult to control, and defects such as graphite phase and carbon-deficient phase (η phase) are prone to appear, especially η Phase, the magnetic saturation of the alloy is generally lower than 125 emu / g, which will seriously reduce the mechanical properties of the material. The current method to eliminate the η phase is to soak the resin powder with ...

AI Technical Summary

Problems solved by technology

This method is more effective for eliminating cemented carbide products with η phase, but basically ineffective for low-carbon cemented carbide products without η phase (magnetic saturation is 125-135emu / g)

In addition, this method needs to coat each cemented carbide product with resin, which is labor-intensive and time-consuming, and small pits are likely to exist on the surface of the product

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