Brittle fracture mechanism of the cemented carbides drill bit for mining

In the process of drilling gas drainage hole in coal mine, early brittle fracture of the cemented carbide appears frequently and the efficiency rock drilling and the safety production of coal mine are seriously affected. In order to study the mechanism of the early brittle fracture failure, investigation methods such as hardness tests, microscopic analysis, chemical analysis and working environment analysis are used. According to the analysis results, low content of Co element decreases the toughness of the cemented carbide material and the abnormal fluctuations of the hardness of rock material are the main reasons which lead to early brittle fracture of the cemented carbide bit. It is suggested that testing and assessing the hardness and ingredients of both the tool and the rock material before drilling are necessary.