With telescopic structure, the kelly bar is mainly used for transmitting torque and feeding pressure to the lower end of the drilling tool to complete the hole-forming operation of the cast-in-place pile. The drill rods used by HANFA are made of high-strength alloy steel pipes, and the internal and external key strips are made of high-strength wear-resistant materials to ensure the efficiency of drilling construction, and have a long life and high reliability.

Inter Locking Kelly Bar

The inter locking kelly bar is suitable for hard formation drilling. With large pressure, the kelly bar is pressed downward by the pressing surface of the inner and outer key strips. Generally, the kelly bar does not exceed 4 knots, and the drilling depth is within 80 meters. Before lifting the drill pipe, the lock type drill pipe must unlock the inner and outer key bars and then raise the drill pipe. The unlocking process is more complicated.

Friction Kelly Bar

Friction kelly bar is suitable for drilling in ordinary soil layers, and it has high drilling efficiency in softer formations. The inner and outer key strips are easy to unlock, and the drill rod is relatively easy to lift. Generally, it is composed of 5 sections of drill pipe, and the drilling depth is deep. Friction drill rods are pressed downward by the friction force between the key bars, and the pressure is small, which is not suitable for drilling hard formations.

It can be equipped with drill rods and drilling tools suitable for various working conditions to meet the requirements of different users.