Kelly bars are a key component on hydraulic rotary drilling rigs. They transfer the torque of the rotary drive and the crowd pressure of the crowd system concurrently to the drilling tool. Our kelly bars consist of 3-6 telescopic tubular sections with a system of drive keys and lock recesses that have been welded onto the outer surfaces. Standard kelly bars are produced with a total of 6 drive keys on each section. The tubular kelly sections are manufactured from high tensile steel to ensure the minimum weight has the right strength for different applications.
Locking kelly bar systems are designed specifically for drilling into hard materials and when a crowd force application is required. Locking kelly bars come with drive rails designed with locking pockets on their length, and corresponding terminal joint locking points. The purpose is to interlock each telescopic element to the inner following one in order to apply the maximum torque and crowd force developed by the base rig.
Due to that, the rotary table inner drive is also equipped with locking pockets. When extracting the locking bar from down the hole, the combination of lifting and rotating clockwise allows the telescopic element to unlock. Locking bars are usually supplied with 3 or 4 telescopic elements.
A friction kelly bar gets its name from the method by which is transfers torque to the drilling tool. The telescopic elements are advanced using ‘frictional contact' from each of the friction drive rails that run down the outside of each kelly bar. These drive rails are driven by the rotary table and the terminal joints of each successively larger in diameter kelly bar. The terminal joint is a long piece on the inside and at the bottom of the kelly bar.
Friction kelly bars are normally available with 3, 4, 5 or 6 telescopic elements as they are primarily used for deep piles in medium hard soil conditions.
Telescopic pipes steel quality: Q345B
Drive rails steel quality: German imported steel plate
Drive stub steel quality: Special forged steel
Drive stub dimensions: 200x200, 150x150 or customized
Outer pipe available diameter: 254, 292, 298, 305, 343, 368, 378, 445…
Upper shock absorber: Damping rubber ring
Lower shock absorber system: Damping rubber ring and damping spring
Telescopic elements Number: 3, 4, 5, 6 others on request
Kelly Bar Performance and Characteristics
1. Use of advanced international six-key distribution technology and standard modular design.
2. With the use of advanced processing equipment, processing technology and unique tooling manufacturing processes, our kelly bar can be used on different drilling machine brands, including XCMG, CSR, SANY, SOILMEC and others.
3. The entire kelly bar set is light weight, high strength, high linearity of the single section and the pipe wall, there is a small seam between sections, and there is an excellent wear resistance on the key plates, meeting the specific requirements for rotary drilling machines.
4. Our kelly bars are manufactured with seamless steel pipes that have been specifically customized using high quality domestic alloys as well as German imported high-strength seamless steel pipes to ensure the dimensional accuracy, position error, mechanical properties and excellent weldability. The small pipes use an alloy hydraulic prop tube, which, with a secondary processing features a strength that can reach more than 800Mpa.
5. The outer keys are made of alloy steel, giving them their high hardness, high toughness and excellent welding performance. After a special heat treatment, the wear resistance is significantly improved, in order to reduce failure rates and maintenance costs.
6. We have three types of kelly bars: interlocking, frictional and combined. The length of the kelly bar depends on customer requirements or the drilling machine parameters. Kelly bars with different torques can be paired with different rotary drilling rig models. Lifting lugs and square heads have multiple connection methods available for users.
7. Complete material specifications ensure we can provide kelly bars for any domestic or imported rotary drilling rigs. Each kelly bar features a full torque and maximum drilling depth of 100meters.
8. Long term maintenance is supplied on all kelly bars, and we have the experience necessary to carry out on-site maintenance services.
In addition to high quality products, we also provide the following services:
1. We have outstanding after-sales services and keep a record of all material sources and manufacturing processes. We also keep spare parts available.
2. Starting from the date the drilling rig leaves the factory, we provide videos for trouble shooting or paid maintenance services for customers.
3. We provide spare parts for maintenance services on the kelly bars at a favorable price.