In the 1970s, with the widespread use of hydraulic rock drills, there was a new demand for rock drill bits. Button bit has the characteristics of high working efficiency, fast drilling speed, and saving work time. It is suitable for high-power hydraulic rock drills, so it has developed rapidly. As an important part of the button bit, carbide has also been widely used.
Carbide was first used in mining roller cone bits and was loved by people because of its simple tooth-fixing process, good rock-breaking effect, and high feed rate. With the change in rock drilling conditions, the market has higher and higher requirements for the strength, toughness, and wear resistance of cemented carbide against cracking and fatigue fracture. From the rock breaking and wear mechanism of rock drilling carbides, the basic requirements for carbides are impact resistance and wear resistance. According to the specific needs, the manufacturer can correctly select the carbide to effectively improve the rock drilling efficiency.
The correct choice of carbide principles
1. For very hard rocks and rock drilling machinery with high impact power, focus on the toughness of the carbide and choose the carbide with high cobalt content.
2. For medium-hard, hard-brittle, and highly abrasive rocks, focus on the wear resistance of carbide and choose the carbide with lower cobalt content.
The selection method of the above carbide grades is just a reference principle. Under specific rock drilling conditions, such as the nature of the rock, rock drilling methods and working parameters of rock drilling equipment must be considered comprehensively.
Cemented carbide is mainly used for inserting button bits and DTH drill bits, which are suitable for drilling hard, medium-hard, and below medium-hard formations in general, and there is a trend of replacing blade-type drill bits in below medium-hard formations and brittle rock formations. In addition, the button bit has a large contact area with the bottom of the hole, which can effectively withstand the impact of rock drilling, and its force state is much better than that of the blade-type drill bit. Therefore, the requirement for cemented carbide is to improve its wear resistance as much as possible while ensuring the toughness of the carbide.
Profile of cemented carbide
Profile of foreign cemented carbides
Different rock types need to use different cemented carbides, and the profiles of foreign carbides mainly include hemispherical and ballistic. The strength and wear resistance of hemispherical buttons are higher than those of ballistic buttons, but the rock drilling efficiency is the opposite.
Profile of domestic cemented carbides
Profile of domestic cemented carbides mainly includes hemispherical buttons, ballistic buttons, and conical buttons. The strength and wear resistance of the hemispherical button is the highest, the ballistic button is the second highest, and the conical button is the lowest. Generally, conical buttons are used in medium-soft rock formations, ballistic buttons are used for rock drill bit gauge buttons in medium-hard rock formations, conical buttons are used for front gauge, and hemispherical buttons are used in hard rock formations.
With the continuous development of new rock drilling equipment and technology, the market demand for rock drilling tools is getting higher and higher, and the quality of cemented carbide will also put forward higher requirements, so manufacturers need to combine the development of the market, continue to conduct in-depth research on the products, and obtain breakthroughs by developing their processes.
