According to the way of connecting with the drill rod, there are tapered drill rods, threaded extension rods, and integral drill rods. The tapered drill rod is a relatively widely used type and belongs to the category of small cross-section rods. During the rock drilling process, the main parts of the tapered drill rod, rock drill, and drill bit are the end of shank and the taper part. Therefore, the overall drill rod and its connection with the part of the geometry and parameters of the choice for the efficiency of rock drilling is crucial.
What is a tapered drill rod?
Tapered drill rod is a hexagonal hollow rod with a shank, the shank is connected to the rock drilling equipment and the rod end is tapered, which can be connected to the tapered drill bit.
Shank adapter handle
The shank adapter handle of the drill rod includes the shank adapter, drill shank, and drill shoulder parts.
Shank adapter
The shank adapter refers to the end of the shank about 30mm. During the drilling process, the end face of this end is in contact with the end face of the rock drill piston, bears the impact of the rock drill piston, and transmits the impact power of the rock drill to the drill rod. Since the impact frequency of the rock drill piston is about 2000~3000 times/min, it is required to have moderate hardness and wear resistance, reasonable geometric structure, and machined dimensions with a certain degree of accuracy, especially the end face should be flat and have a low machining roughness. Therefore, the end part must have the fatigue strength to resist the high-frequency impact of the rock drill piston.
Drill shank
During the drilling process, the drill shank is directly connected and matched with the hexagonal sleeve of the rock drill. Therefore, whether its matching performance is good or not is closely related to the geometric structure of the drill shank and the selection of parameters.
Drill shoulder
The drill shoulder mainly plays the role of fixing the drill rod on the rock drill during the rock drilling process.
Rod body
The rod body of the tapered drill rod generally refers to the part from 50mm in front of the drill shoulder to 50mm behind the cone. It is not processed in the brazing process, and its geometric structure and parameters are consistent with those of hollow steel.
Cone
The cone structure and parameters of the tapered drill rod vary from country to country. Considering the requirements for the connection and coordination between the drill rod-cone and the drill bit taper hole, the smaller the cone angle α of the cone is, the greater the expansion stress of the cone on the taper hole will be; the greater the cone angle α is, the greater the expansion of the drill bit shell stress is reduced, but the connection is slack.
The geometric structure and parameters of each part of the tapered drill rod affect its rock drilling efficiency and service life, and its quality has a great relationship with the steel type and rolling quality of the drill steel. In addition, Whether the manufacturing process is reasonable and whether the forging equipment is advanced and sophisticated is also extremely important. In particular, since the hollow brazing steel type adopts alloy steel, the material performance is significantly improved, and brazing technology and equipment on the quality of brazing rod is more prominent.
Process flow of tapered drill rod
Although the degree of mechanization and automation of the production process of each drill rod manufacturer is different, the basic manufacturing process is similar. The typical process flow is:
Selection of hollow steel – Quality inspection of incoming steel – Sizing material – Straightening – Induction heating – The end of shank adapter reaming and sizing – Flat end chamfering of the shank end – Induction heating – Forging drilling shoulder – Finishing drill shoulder – Forming of brazing cones (machining or forging) – Inspection of drill rod geometry – Induction heating – Shank adapter end quenching – Shank adapter end tempering – Shot peening treatment for the whole surface of drill rod – Anti-corrosion treatment for the whole drill rod – Quality inspection of finished drill rod – Packaging-Storage.
Features of tapered drill rods
High efficiency
The tapered drill rod is made from high-strength, high-wear-resistant alloy material, offering excellent wear and corrosion resistance. Its unique taper design enhances power transmission during drilling, reduces energy loss, and improves drilling efficiency.
Stability
The design of the tapered drill rod is exquisite. The drill rod can maintain good straightness in drilling, reduce deviation and swing, and ensure drilling accuracy and safety.
Adaptability
The parameters such as length, diameter, and taper of the tapered drill rod can be adjusted and customized according to actual needs to adapt to different engineering needs and rock characteristics. This design gives the tapered drill rod a broader range of applications and greater adaptability.
Durability
The tapered drill rod is manufactured using precise technology, resulting in a long service life and high durability. It can withstand harsh working environments for extended periods.
Selection of tapered drill rods
Choosing a suitable tapered drill rod is crucial to improving engineering operation efficiency and safety. When choosing a tapered drill rod, it should be selected according to specific engineering needs and the use environment, considering factors such as rock hardness, structure, and crushing requirements.
Conclusion
In short, the tapered drill rod is an essential tool in engineering construction, and its performance and quality directly affect the safety and stability of the project. By understanding its composition, manufacturing process, and other aspects, we can better understand it, and using the product, we can also choose the product parameters that are more suitable for our project and escort the engineering construction.
