In the oil, natural gas, petrochemical, nuclear power, and processing industries, pressure vessels, thermal pipeline joints, valves, pumps, and machinery will face the problem of how to control the tightness of bolts. It is required that the gap between the flanges should be uniform, the sealing surface should be installed tightly, the connection points should not leak, and the use of media and gaskets should be good. Therefore, users need to master the knowledge of bolt pre-tightening force, hydraulic torque wrench operating performance, safety precautions, maintenance and maintenance knowledge, and how to use hydraulic torque wrenches safely and reasonably to save time and effort to uniformly apply a constant torque to the bolts. Finally, the task will be completed quickly and accurately.

Over the past few decades, even with the use of high-quality and high-precision tools, it has been impossible to stop the occurrence of leaks. Traditional methods such as sledgehammer percussion and manual trigger are completely judged by human feelings, and there is no precision at all. There are two unknown factors whether the nut is turned to the proper position: for torque, the friction coefficient between the rotating surface and the thread; for tension, the estimated value of over-tension and manual tightening of the nut. In addition, various application factors, working conditions, fitting tolerances, perpendicularity, and friction coefficient of the bolts and nuts used affect the bolt fastening factors, making the accuracy of bolt fastening difficult to control. In the heavy industry, the economic loss caused by the leakage due to the sealing problem and the failure due to the loose bolt is very huge. If the remaining tensile force of each bolt is the same, the flange can obtain a uniform load. If the load is uniform, the flanges will be closed in parallel and there is no leakage. Correctly tightening the bolts and accurately controlling the pre-tightening force of the bolts is the only way to reduce leakage and bolt looseness.