Hydraulic Bolt Tensioning

Hydraulic bolt tensioning service involves using hydraulic tools and equipment to accurately apply tension to bolts in various applications, ensuring proper and uniform clamping force. This service is commonly utilized in industries such as construction, oil and gas, power generation, and heavy machinery.

Unlike conventional methods, it does not use torque and does not require any forceful turning of the nut or bolt, like impact wrenches, flogging spanners or hydraulic torque wrenches.  All of these methods have one common enemy: FRICTION.  Overcoming thread friction and friction between the nut and the washer uses up over 80% of the torque energy applied to the nut or bolt, leaving less than 20% of the energy to produce useful tension in the shank of the bolt.  Variations in this friction loss, from bolt to bolt causes non uniform tension in bolts that have been tightened to the same torque or impact wrench setting.


Here’s how hydraulic bolt tensioning service typically works:


  1. Assessment and Planning: Initially, a team of technicians or engineers assesses the specific requirements of the bolting application. This includes considering factors such as bolt size, material, and the desired clamping force.
  2. Selection of Hydraulic Tools: Based on the assessment, appropriate hydraulic bolt tensioning tools are selected. These tools are designed to fit various bolt sizes and configurations.
  3. Preparation of Bolts: The bolts are cleaned and prepared for tensioning. This may involve removing any debris, rust, or old lubricants from the bolt threads to ensure proper operation.
  4. Installation of Hydraulic Tensioners: Hydraulic tensioners are fitted onto the bolts in the desired pattern. The tensioners are positioned in such a way that they can evenly distribute the clamping force across the joint.
  5. Application of Tension: Hydraulic pressure is applied to the tensioners, causing them to exert a controlled and uniform force on the bolts. This process elongates the bolts slightly, creating tension in the bolted joint.
  6. Torqueing: In some cases, after tensioning, additional torque may be applied to the bolts to achieve the required preload. This ensures that the bolts remain securely tightened under operating conditions.
  7. Verification and Testing: The applied tension is verified using specialized tools such as load cells or ultrasonic equipment. This ensures that the specified clamping force has been achieved and that the bolted joint is properly secured.
  8. Documentation: Detailed documentation of the tensioning process, including bolt specifications, applied tension values, and any deviations from the planned procedure, is recorded for quality assurance and future reference.
  9. Post-Service Inspection: Once the tensioning process is complete, a final inspection of the bolted joints may be conducted to ensure that they meet safety and performance standards.


Hydraulic bolt tensioning services offer several advantages over traditional bolting methods, including increased accuracy, reduced risk of bolt failure, improved safety, ease and speed of operation, which can be simultaneous, give downtime reductions, reduce costs and increase productivity for tightening critical bolted joints.. By employing hydraulic tools and techniques, precise and uniform tension can be applied to bolts, contributing to the integrity and reliability of critical infrastructure and equipment.