Experimental Study on Bit Tooth Made of Nano-Cemented Carbide Composites in Air Hammer Drilling

It is fracture, wear and abscission of bit tooth that make up of the main failure forms for the air hammer bit, which have badly restricted the further popularization and application of the air hammer drilling. The main reason is that the ordinary cemented carbide tooth is difficult to meet the complex conditions of the air the hammer drilling. Therefore, this research puts forward a new thought that we strengthen the carbide tooth by adding the nano-Al2O3into the substrate materials of WC-Co. According to the study of several formulas of nano-composites, the test of sample performance, experimental study of impact abrasive wear and microstructure, we draw some conclusions that adding amount of nano-Al2O3can refine grain, make microstructure more uniform and improve the wear resistance of composites, but also can enhance the strength of boundaries of WC-Co and transform the fracture form from the intergranular fracture to the transgranular fracture. Meanwhile, it can also improve nano-composites comprehensive performance by adding rare earth. The result for site test of bit shows that comparing with the bit equipped the original carbide teeth, the efficiency of rock breaking of the bit equipped nano-composites teeth increase by 20% and the service life increase by 80%.