In mining, tunnel excavation, and other projects, the rock drill bit is a critical rock drilling tool, and the choice of its material is directly related to drilling efficiency and service life. Cemented carbide, as a material with high strength, high hardness, and excellent wear resistance, is increasingly used in rock drill bits. This article will explore the significant advantages of cemented carbide in rock drill bit applications and help readers better understand this material.
Basic properties of cemented carbide
Cemented carbide is an alloy material made by powder metallurgy using rigid compounds of refractory metals (such as tungsten carbide) as the matrix and adding bonding metals (such as cobalt and nickel). It has the characteristics of high hardness, high strength, high wear resistance, high corrosion resistance, and good thermal stability. These characteristics allow cemented carbide to exert excellent performance in rock drill bits.
Application advantages of cemented carbide in rock drill bits
Efficient drilling
The high hardness and strength of cemented carbide enable the rock drill bit to easily cope with a wide range of rock hardnesses during drilling. Compared with drill bits made of traditional materials, carbide drill bits can penetrate rocks better, improve drilling efficiency, and shorten the construction period.
Long service life
The excellent wear resistance of cemented carbide allows the rock drill bit to maintain good drilling performance during long-term use. Compared with traditional materials, carbide drill bits have a longer service life, reduce the frequency of drill bit replacement, and reduce maintenance costs.
Good corrosion resistance
In wet and dusty mining environments, rock drill bits are often prone to corrosion. The outstanding corrosion resistance of cemented carbide can effectively withstand erosion from the external environment, ensuring the stability and longevity of the drill bit.
Strong thermal stability
During drilling, the rock drill bit generates a large amount of heat. The high thermal stability of cemented carbide enables the drill bit to maintain stable performance in high-temperature environments and is not prone to deformation or damage.
Carbide grades for rock drill bits
Most grades of cemented carbide used in rock drill bits are tungsten-cobalt coarse-grained alloys. Due to the different cobalt content in the alloy, its range of uses is also different. When used, it should be selected reasonably according to the geological conditions of the mine to achieve good results. The alloy grade representation method takes YG8c as an example. Y represents cemented carbide, G8 represents the percentage of cobalt in the alloy, and the additional letter c represents coarse particles (x represents fine particles, and no letter represents medium particles).
Application range of cemented carbide grades for rock drill bits
| Alloy grade | Scope of use |
| YG4c | Suitable for embedding in geological exploration core drill bits, hand-held or stand-type electric drills, and pneumatic drill bits in coal mining, coal cutter picks, etc. |
| YG6 | Embedded rotary drilling bits, coal electric drill bits, and buttons for manufacturing small button bits, used for excavation of hard and medium-hard rock formations. |
| YG8 | Inlaid rotary drilling bits and impact rock drill bits. Core drill bits for geological exploration, oil well drilling scraper drill bits, handheld or bracket-type electric drill bits, processing and drilling tools for natural stone processing and construction installation, and small button bits, etc. |
| YG8c | Embedded impact rotary and rotary impact rock drill bits, coal cutter picks, tools for processing granite stones, stone wall drill bits used in construction and installation projects, petroleum cone drill bits, etc. |
| YA85 | Suitable for button bits to drill into medium-hard rock formations. |
| YKR4 | Suitable for small and medium tooth drill bits and DTH drill bits with high air pressure and high impact. |
| YK20 | Embedded for the production of drill bits and roller cone bits used in excavating medium-hard and hard rock formations. |
| YK25 | Embedded impact rotary rock drill bits for drilling in medium-hard and hard rock formations. |
| YK252 | Suitable for use as a welding drill bit for drilling in hard rock formations. |
| YK15 | Suitable for use as a welding drill bit for drilling in very hard rock formations. |
| YG11c | It is suitable for flakes, column teeth, buttons, and roller cone bits to drill hard rock formations. Additionally, it is used as stone wall drill bits in construction and installation projects. |
| YG13c | It is suitable for a roller cone bit for oil well drilling and can drill into medium-hard or hard rock formations. |
| YG15 | It is suitable for use as a bit for impact rock drills to drill hard and extremely hard rock formations. |
| YK30 | It is suitable for use as a bit for impact rock drills to drill hard and extremely hard rock formations. |
Correct selection of carbide for rock drill bits
When selecting the alloy grade of the drill bit, you must pay attention to the following points:
- Physical and mechanical properties of rocks. Such as rock hardness, friction, and its occurrence characteristics – compactness and fissures. Alloys used for impact drill bits, the must-have characteristics are that they are not easily damaged under impact loads and have high wear resistance. However, wear resistance and toughness are inversely proportional in drill bit alloys. The alloy has high hardness and wear resistance, but its bending strength will decrease accordingly. On the contrary, if the alloy has high flexural strength and good toughness, its hardness and wear resistance will decrease. The wear resistance and toughness of the drill bit are related to the cobalt content and tungsten carbide grains in the drill bit alloy. If the cobalt content is low, the hardness will be high, and the wear resistance will be good, but the toughness will be low. Alloys with coarse grains have low hardness but good toughness. Therefore, when selecting a drill bit alloy, it is required to improve the wear resistance of the alloy as much as possible while ensuring that it has sufficient toughness and can resist impact. Therefore, drill bit alloys mostly use coarse grains to ensure their toughness.
- Rock drill model. Drill bit alloy selection and rock types and rock drill type compatible. Generally, rock drills with extremely hard rocks and high-impact power should focus on toughness, often choosing a higher cobalt content alloy. Medium-hard, hard, brittle, and highly abrasive rocks, focusing on wear resistance, often choose alloys with lower cobalt content.
- Method of breaking rocks.
- Equipment capabilities.
Conclusion
Cemented carbide has significant advantages in the application of rock drill bits. Its high hardness, wear resistance, thermal stability, and corrosion resistance make the rock drill bits maintain excellent performance in harsh working environments. In real projects, adopting cemented carbide rock drill bits can significantly improve rock drilling efficiency and quality and reduce energy consumption and costs. Therefore, the carbide rock drill bit is a high-performance tool worthy of promotion and application.
By exploring the significant advantages of cemented carbide in the application of rock drill bits, it becomes evident the crucial role this material plays in modern engineering. With ongoing advancements in science, technology, and process optimization, carbide rock drill bits’ performance and application range will continue to expand. It will provide more efficient and reliable drilling tools for mining, tunnel excavation, and other projects.
