In mining, tunnel excavation, and various geotechnical engineering operations, rock drill bits are essential tools at the core of the operation. Their performance directly affects the efficiency, cost, and even the safety of the entire project. As the key material in drill bits, the performance of cemented carbide determines the service life and operating effect of rock drill bits. So, what specific performance requirements do rock drill bits place on cemented carbide?
High Hardness
Tungsten-cobalt cemented carbides are renowned for their hardness. In rock drilling, the carbide buttons of the bit must directly engage with hard rock surfaces. When the rock drill is powered by a hydraulic system to deliver high-speed rotary and percussive motion, the carbide buttons strike the rock repeatedly with high-frequency impacts and cutting forces. Only carbide materials with sufficient hardness can maintain their shape and resist wear or deformation under intense resistance.
High hardness is crucial for hard rock drilling, in particular, to ensure the buttons can continue penetrating dense rock and complete the drilling task efficiently.
Excellent Wear Resistance
Continuous contact between the carbide buttons and the rock surface generates friction during drilling. The irregular texture and presence of abrasive mineral particles further increase this friction. If the carbide lacks wear resistance, it will wear down quickly, lowering drilling efficiency and requiring frequent bit replacements — driving up operational costs.
Therefore, carbide buttons must exhibit strong wear resistance to maintain cutting performance over extended periods. Enhanced wear resistance means fewer bit replacements, reduced costs, and improved overall efficiency. Without it, the drilling process would suffer constant interruptions for maintenance or tool change-outs, wasting both time and resources.
Superior Impact Resistance
In the rock-breaking process, carbide buttons are subjected to reverse impact and cutting forces from the rock, accompanied by high-frequency impacts. This impact comes not only from the rebound of the rock but also from the vibration of the rock drill. Carbide materials must have high impact resistance to endure these forces without chipping, cracking, or deforming.
Improved impact resistance depends on the material’s internal microstructure and mechanical properties. The impact toughness of cemented carbide can be significantly improved by optimizing the alloy composition and improving the preparation process. As a result, even under the harshest rock drilling conditions, the carbide buttons can maintain stable performance, ensuring smooth rock drilling operations.
Adaptability to Varying Working Conditions
Drilling conditions vary greatly, and different applications require different performance characteristics from the carbide. In coal mining or soft rock excavation, ultra-coarse-grain carbide is often used. The average WC grain size of these carbides is more than 6 μm with excellent thermal shock resistance and thermal fatigue resistance, which is very suitable for continuous mining of soft rock under extreme working conditions.
In contrast, hard rock drilling demands higher hardness and wear resistance. Some leading manufacturers offer specialized carbide grades for this purpose, with hardness ratings as high as 90.6 HRA and excellent performance in field tests, where wear, rather than breakage, is the primary failure mode.
Such diverse needs drive ongoing innovation in carbide manufacturing. By adjusting alloy composition and production processes, suppliers can tailor materials to meet specific field requirements, delivering more reliable and efficient solutions.
Durability and Stability
In complex drilling environments, the durability and stability of carbide buttons are crucial to maintaining uninterrupted operations. Poor durability can lead to frequent failures, resulting in downtime and repair costs. Lack of stability can reduce drilling accuracy and compromise project quality.
Improving material quality and bit design to enhance these characteristics ensures more efficient and reliable drilling, especially in high-risk or precision-demanding scenarios.
Material Selection
With advances in materials science, modern cemented carbides offer improved strength, toughness, wear resistance, and impact resistance. Choosing the right carbide material is vital for companies involved in drilling projects. Each type of rock and mining environment requires specific carbide properties.
Hard rock demands higher hardness levels, while soft rock may benefit more from toughness and thermal resistance. Choosing the wrong material can lead to poor efficiency and increased operational costs. Therefore, understanding the properties of the carbide is key to selecting the right drill bit for the job.
Conclusion
In the challenging world of rock drilling, which is full of challenges and opportunities, the performance of rock drill bits, as the pioneer of rock breaking, is closely related to the performance of cemented carbide. From high hardness and wear resistance to excellent toughness and adaptability to various conditions, each performance index of cemented carbide is like a finely tuned gear in the larger machinery of drilling operations.
Only carbide that meets these requirements can make rock drill bits work stably in complex rock drilling environments, improve the efficiency and quality of rock drilling operations, and provide a strong guarantee for the smooth progress of engineering projects. As technology continues to evolve, we can expect even more advanced carbide materials to emerge, further enhancing the effectiveness and efficiency of drilling operations.
