Machinability of CBN Tool in Turning of Tungsten Carbide

Tungsten Carbide have extremely high hardness and wear-resistivity compared with conventional steel materials, and it is expected that the Tungsten carbide can be applied widely to dies and molds in the near future. In order to develop an efficient machining method of Tungsten Carbide for the dies and molds, series of cutting experiments were carried out to turn the sintered Tungsten Carbide materials with CBN tool. The selected sintered Tungsten Carbide workpieces are those containing Tungsten Carbide grains with mean grain size of 5μm, and 15wt%, 20wt% and 22wt% of Cobalt binder. The sintered CBN tool selected contains super-fine grains of CBN with mean grain size of 1μm. The cutting speed was varied from 10m/min to 60m/min, and the tool wear and the surface roughness were measured. It is concluded that the tool wear is less when cutting the sintered Tungsten Carbide containing larger amount of Cobalt binder. The surface roughness of about 2μm in Rz is obtained.