In the vast field of geological exploration and mining, DTH drill bits are core tools, and their performance and stability are directly related to the efficiency and cost of drilling operations. However, the problem of DTH drill bit tooth loss has become a bottleneck restricting the development of this field. Tooth loss will not only hinder the drilling progress and increase the cost of maintenance and replacement but also cause further damage to the equipment and affect the overall operation safety. Therefore, an in-depth exploration of the root causes of DTH drill bit tooth loss and effective preventive measures are of great significance to improving drilling efficiency, reducing operating costs, and ensuring operation safety. This article will analyze the main reasons for DTH drill bit tooth loss and share some preventive measures for your reference.
Causes of tooth loss in DTH drill bits
Increased wear of the bit body
- Material fatigue: under long-term high-intensity work, the bit material is prone to fatigue accumulation, impacts in high-hardness rocks, which will accelerate the wear rate of the bit surface, resulting in a rapid reduction of the contact surface between the gauge button and the bit, the holding force is reduced significantly.
- Harsh working environment: environments such as moisture, dust, or corrosive gases will also accelerate the corrosion and wear of the drill bit, further affecting the stability of the gauge button.
Plastic deformation of tooth holes
When the drill bit impacts the rock, it is subject to the reaction force of the rock in the axial direction and the torsional shear stress caused by the rock drilling resistance torque in the circumferential direction. The impact force and shearing force are transmitted to the drill bit perforations through the carbide button, causing plastic deformation of the hole. As the number of impacts increases, the plastic deformation at the upper end of the tooth hole continues to expand to form a bell mouth, and the force tightening the carbide button decreases, causing the carbide button to loosen and then fall off.
Improper pressing process
- Operational errors: during tooth fixing by cold pressing, if the operator is unskilled or the equipment is not precise enough, it may easily lead to uneven distribution of the tooth pressing force, excessive local pressure, and damage to the tooth holes.
- Material matching problem: the thermal expansion coefficient, hardness, and other physical properties of the materials of the drill bit and carbide button are very different, which may also have adverse effects during the tooth pressing process, such as micro-cracks caused by inconsistent thermal expansion and cold contraction.
Unreasonable amount of interference
- Design calculation error: the design of the amount of interference requires precise consideration of material properties, working conditions, and other factors. The design and calculation of minor deviations may lead to the actual use of the process of friction or tooth hole expansion cracks.
- Manufacturing deviation: during the manufacturing process, due to processing accuracy limitations and lax quality control, the actual interference amount may deviate from the designed value, affecting the tooth-fixing effect.
Preventive measures for tooth loss of DTH drill bits
Strengthen drill bit protection and maintenance
- Use highly wear-resistant and corrosion-resistant materials to manufacture drill bits to improve fatigue resistance.
- Regularly check the wear of drill bits and replace severely worn drill bits in time.
- Take protective measures to reduce the contact between the drill bit and corrosive substances in harsh working environments.
Optimize the design and material of the tooth holes
- Use high-strength and high-toughness materials to manufacture tooth holes to improve their resistance to plastic deformation.
- Optimize the tooth hole structure design, reduce stress concentration areas, and delay the occurrence of plastic deformation.
Precisely control the tooth-pressing process
- Strengthen the training of tooth-pressing operators to improve their operating skills and process level.
- Regularly check and maintain tooth pressing equipment to ensure its accuracy and stability.
- Optimize tooth pressing process parameters such as tooth pressing force and holding time for different materials and working conditions.
Precisely control the amount of interference
- Strengthen the accuracy and precision of design calculations, fully consider various influencing factors, and formulate a reasonable range of interference.
- During manufacturing, strengthen quality control and testing methods to ensure that the actual interference is consistent with the design value.
- Carry out test verification and optimization adjustments for different materials and working conditions to obtain the best tooth-fixing effect.
Conclusion
DTH drill bit tooth loss is one of the common problems in drilling operations, and its causes are complex and diverse. From the wear of the drill bit body, the plastic deformation of the tooth hole, the improper tooth pressing process, and the unreasonable selection of the interference, each link may become a potential risk point for the drill bit tooth loss.
However, in the face of these challenges, we are not helpless. By adopting high-strength and high-wear-resistant materials, optimizing the design of the drill bit and the tooth hole, finely controlling the tooth pressing process, and accurately adjusting the interference, we can effectively reduce the risk of drill bit tooth loss and improve the service life and stability of the drill bit. At the same time, strengthening the training and management of operators to ensure that they master the correct operating methods and maintenance skills is also an indispensable part of preventing drill bit tooth loss.
With the advancement of science and technology, we have reason to believe that the problem of DTH drill bit tooth loss will be more effectively resolved. In this process, every practitioner should maintain a keen insight and unremitting spirit of exploration, actively seek more scientific, reasonable, and efficient solutions, and jointly promote the healthy development of the geological exploration and mineral mining industry.
