Grasp the Degree of Bolt Tightening

Bolt tightening degree
The bolt is subjected to two forces, one is downward and the other is upward. The bolt rotates down along the thread, and a downward axial force is generated in the process of contact with the thread. At the same time, there is an upward force corresponding to the downward axial force. This force comes from the upward distributed force generated by the contact between the nut and the lower plane. A tightened bolt should ensure that the upper and lower forces are balanced with each other.All ductile materials have one thing in common, that is, there is a limit to the stress tolerance. In mechanics, this limit is represented by a stress-strain curve. In the process of screwing the bolt, the bolt is a kind of elastic part, and its elasticity will take effect. As the bolt is tightened gradually, the elastic effect of the bolt will approach a limit. Once this limit is broken, the bolt will enter the yielding stage from the elastic stage. Once the bolt enters the yield stage, it will produce permanent deformation. This deformation is irreversible, which means that the bolt will fail. It can be seen that the bolt is not tightened as tightly as possible.