Tungsten Copper Power Warm Compacting Process — Key Technologies(2/2)

Continued from the preceding paragraph, we will discuss the key technologies of tungsten copper composite powder warm compacting process according to the aspects above.

2. Lubricant: In the traditional process, lubricant used in general when the temperature was raised to 120-150 ℃, it is difficult to ensure the fluidity of the powder, the powder is mixed performance by a certain influence. Therefore, the choice of lubricant is also can not be ignored. It should meet the glass transition temperature of 130-150 ℃, low coefficient of friction (temperature, friction coefficient further reduced in favor of a metal powder and die wall friction and powder particles to a minimum, thereby reducing the pressure and pressing off clamping force), soluble in volatile solvents (powder dry and easy to make the surface of the powder particles uniformly coated with a thin layer of lubricant film), can effectively prevent or slow down the oxidation of tungsten-copper alloy powder (usually metal powder is oxidized, increased oxygen content will affect its final properties), the decomposition temperature range is wide (should be more gentle lysis, avoid large amounts of gas, resulting in the expansion of the volume of powder metallurgy parts), non-toxic lubricant after decomposition, do not pollute the environment .

3. Temperature Control: Temperature and pressure molding preheating temperature between 100 ~ 150 ℃. Because usually between room temperature and the temperature of hot pressing temperature is between, this has been known as warm compacting process. The temperature and pressure above the temperature control of the glass transition temperature of the polymer lubricant or below the melting point of the lubricant in the viscous flow state, both have a certain cohesiveness and some lubrication, it is conducive to the particle surface and spread flow. Whether temperature is too high or too low will destroy the lubricant film and caused failure.

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