Why Hydraulic Stud and Bolt Tensioning?
HTI’s Hydraulic Stud and Bolt Tensioning Systems are the simple and efficient answer to common stud and bolt tightening problems, and provide: • Accurate and Repeatable Stud Loading – Engineers design a flange or joint knowing the stud tension necessary for it function as intended. Under–tightened, over–tightened or unevenly–tightened studs can lead to the failure of the joint. Tensioners produce a known tension in the stud. Accurate stud tension is difficult to attain using torque, because friction has a significant effect on the torque–tension relationship. For example, the torque required to stretch a 2″–8UN stud to 35% of its yield strength varies between 1,400 ft–lbf (using a moly–based lubricant) and 8,360 ft–lbf (“dry”, with no lubricant). If the operator failed to lubricate the threads and nut surface and torqued dry, the resulting stud tension would be only 6% of yield (Tension = 17,100 lbf) instead of 35% of yield (Tension = 102,300 lbf)! • Fast Operation – Using Hydraulic St
