Frequent Problems in Tungsten Copper Electrode Machining

Tungsten copper electrode machining belongs to powder metallurgy, which has complex process so that there are some frequent problems remain, such as the cracks, the porosity defects and blow hole, etc. Take appropriate measures to solve these issues, which can improve the density of sintered sample.

1. Cracks

This is the most common problem, since the suppression of the pressure too fast, too late to the powder in the gas discharge, the expanded relief elastic aftereffect caused cracks. In addition, the external surface of the sample during sintering of copper will evaporate, leading to the outside of the sample binder phase - copper loss, and prone to cracking. The common solution is to increase the pressure and keep sufficient dwell time to force the gas between grains to discharge favorably. As for the loss of the phenomenon of the copper surface, the current general applications will be used in the method of removing the surface machining section.

2. Blow hole

Besides, tungsten copper composite blow hole from the high temperature copper dissolved in some of the gas can not be effectively excluded during solidification caused, such as vapor and hydrogen. The vapor reacted with the carbon from graphite electrode to form hydrogen (H2) and carbon dioxide (CO2) so that the copper at high temperatures a large amount of dissolved hydrogen can not be completely excluded during solidification, blow holes are formed. A common solution is to avoid all risks of water vapor during sintering, the other is still to gradually increase the pressure in the pressurizing process, and ensure sufficient dwell time, which discharge the gas between grains successfully.

3. Porosity defects

Its production is mainly concentrated in the solidification process and prone to firing in the central part of the sample, which is mainly due to solidification of the central portion of the higher temperature, ambient temperature is relatively low because the site first and then solidified but sucked in part copper formed. In practical application, this kind of defect distributes a little in tungsten copper electrode issues, but it is also difficult to be eliminated.

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