Green Machine Work of Tungsten Carbide

The appearance of the common tungsten carbide products prepared by hard sintering process is limited, and the hardness of the parts is high while the brittleness is great. Therefore, the subsequent processing of cemented carbide parts mainly adopts mechanical grinding and special processing, of which the cost is high. Machine work on the green before sintering can well solve the problem of limited size, simple form and high cost, expanding the scope of application of tungsten carbide.
 
Green machine work has many advantages, such as cutting tool life is long, can produce complex shape parts etc. However, the strength of powder metallurgy parts is very low. As a result, the above described advantages are easy to be processed by green resistance components of low offset, which may make the green part edge broken or entire part destroyed. The green strength must be improved to achieve the processing requirements.
 
green-pressing of tungsten carbide image
 
It is generally believed that the powder metallurgy compacts have machinability when the strength of powder metallurgy compacts reaches 15~30Mpa, like other forming methods. However, the conventional powder metallurgy process is difficult to achieve the required high billet strength (about 20MPa). Therefore, green machine work has not been widely applied. In order to achieve the required high billet strength, a lot of scholars have studied this technology.
 
The powder particles between atoms and hardening strong prior to sintering has not formed, but by the mechanical engagement between the main welding and particles. The cutting force and the temperature of the cutting zone are kept in a low range, the wear and the heat generated by the tool are less, and the production efficiency is high, which can solve the problem that the size and shape of the cemented carbide powder metallurgy parts are limited, and the production cost is high, and the application range of the cemented carbide is enlarged.
 
Because of the low strength and low processing resistance of tungsten carbide, the roughness of machined surface is poor. In the process, edge damage or damage is prone to occur. Therefore, improving the green density and strength is the key of realizing the green machine work.
 
 

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