Bolt Torquing & Tensioning
Bolt tensioning is performed by hydraulically stretching a stud to a calculated pre-load value and then hand-tightening a nut.
Bolt torquing is done by using a wrench to turn a nut against a combined resistance created by friction and material elongation. The torque causes the bolt to stretch and creates the required pre-load on the stud.
The main difference is how torquing and tensioning are performed to achieve the desired pre-load. Torquing requires a specific rotational force (torque) to achieve a calculated pre-load, whereas tensioning creates a direct pre-load via hydraulic load cells.
Advantages of tensioning
- Consistent and repeatable results
- Bolting surface finish and lubrication are not a factor in achieving the desired pre-load
- Suitable for larger diameter bolting
Advantages of torquing
- Can be performed with common tools
- Torquing procedures are well understood in the industry
- Typically required on legacy equipment that does not have clearances for hydraulic tensioning
