Drill bit drilling directly into rock is the most vulnerable part of drill bit.According to the rock drilling alloy shape bit used, it can be divided into the following types: flake bit (mainly including one word bit, three edge bit, cross bit, X bit) and column tooth bit.
Flake bit is the earliest, most widely used and most productive bit in China.One of the chisel head about to account for more than 80%, mainly used for small hole, shallow hole drilling rock.Due to the structure and stress of the chip bit, the rock breaking efficiency is low, the penetration is slow, the amount of alloy is large and the waste is easy to occur.And its maximum diameter is limited because of its structure and stress.At present, in many neutral and brittle rock conditions, flake bit is more and more replaced by ball tooth bit.
The ball tooth bit is composed of cemented carbide column teeth embedded on the bit body. The bit is free in tooth distribution, and the number and position of the edge and middle teeth can be reasonably determined according to the diameter of the hole and the small rock breaking load. The diameter of the bit is not restricted.Moreover, because it is multi-point crushing, the rock breaking efficiency is higher, which can not only effectively eliminate the blind area of rock breaking, but also avoid the repeated crushing of debris.The typical hardness of the alloy column teeth is higher, the non-grinding life is longer, and the heavy grinding work is less, which shows a higher value under the working conditions of mining.In view of the harsh drilling conditions of the drill head, the requirements for the steel body material of the drill head should be: the material has high plasticity, toughness and hardness under the condition of heat treatment;Materials should have high fatigue strength and wear resistance;Materials should have a high air cold hardening;We adopt the technology of hot-stamping forming, vacuum quenching, tempering and hot-pressing for fixing teeth, which ensures the strength and hardness of the shell of bit head and the reliability of fixing teeth. The average drilling life of small diameter ball tooth bit in medium and hard rock reaches 132 meters and 108 meters respectively.
