Control of pre-tightening tapping screw suppliers measuring torque wrench-measure the pre-tightening torque, as shown in the figure below; fixed torque wrench-when reaching a fixed tightening torque

Major diameter D or d Major diameter refers to the diameter of an imaginary cylinder that coincides with the bottom of the internal thread or the top of the external thread

In the connection of threaded fasteners, the main possible factors that lead to the relaxation of the pre-tightening force are: contact surface subsidence, mutual influence of bolt groups, seal ring deformation

The pre-tightening force control method of important bolt connection. However, measurement devices (such as micrometers, ultrasonics, etc.) are inconvenient to implement in specific connection structures and affect production