Selection of Grades and Types for Tungsten Carbide Drilling Bits
1) Selection of tungsten carbide grades
The right selection of tungsten carbide grades is one of the most important factors that guarantee the effective application of tungsten carbide. Attention should be paid to the following when the selection of grades is done :
a) The properties of the rock formations ,such as hardness ,frictional characteristics, and their configuration like compactness, fissures ,joints, caverns etc.The basic principle is that the harder the formation of rocks to be drilled, the much tougher the drilling bits should be.However,they should not be too soft and it is to say the wear resistance should not be too low, since it will increase the consumption of tungsten carbide and reduce the efficiency in the drilling as well; Cross drill bits should be used if the rock formations are full of fissures without regards to the hardness of the rock formations and what types of drilling machines used .
b) The types of rock drilling machines ,light or heavy types etc
c) Method of fragmenting the rocks formations(cutting ,shearing ,crushing,impackting etc)
d) Capacity of the equipment (e.g. how or high air-pressure)
2) Selection of types of tungsten carbide drilling bits
K0 type drilling bits are for embedding chisel drill bits for side face drilling and solid chisel drill bits with diameters of 25~49mm.Some of the types are for embedding drill bits of big diameters for center drilling operations.K048 and K049 are mostly used for drilling highly frictional rock formations.
K1 type drilling bits are for embedding chisel and cross drill bits of various diameters .The drilling efficiency of chisel drill bits is higher than that of cross drill bits .Cross drill bits can withstand a high load .Chisel drill bits are used for drilling homogeneous rock formations of various hardness and the impact load of the drilling machines shall be less than 6 kilograms. It is advisable to use cross drill bits for drilling rock formations with high hardness
