A study on comparison of bolt tensioning applied by conventional torque method and hydraulic tension method

Bolted assemblies are the most commonly used joints in mechanics and bolted joint requires preloading to perform its function successfully. Preloading is usually generated immediately after tightening the bolt by conventional torque wrench method. Other than torque wrench method, hydraulic tensioning a new method of bolt tightening has been used in industry recently. In this study, an experimental investigation on two types of tightening methods (conventional torque wrench and hydraulic tensioning) is performed. Bolt's behavior during tightening, and advantages-disadvantages of both tightening methods are investigated. The study comprises two tightening varieties of experiment; static bolt behavior and dynamic bolt behavior in a bolted joint. A total of 24 bolts, consisting of 8.8 grades and three different diameters (M14, M16 and M18) with almost the same (150 mm) lengths, were tested by employing both tightening methods. Static tests/investigations were performed in laboratory site of Mechanical Engineering of Gaziantep University of Turkey while dynamic tests/investigations were performed by applying cyclic load in laboratories of Karabuk University of Turkey.