High-strength bolt for universal shaft of rolling mill

The high-strength bolt comprises a bolt head and a screw rod which are connected into a whole, a counter bore is formed in the bolt head, the screw rod comprises a threaded section and a smooth section, the threaded section is arranged at the end, away from the bolt head, of the screw rod, the smooth section is provided with at least one reducing part, and the diameter of the reducing part is larger than that of the screw rod. And the diameter of the reducing part is smaller than that of the screw rod. When an existing bolt is designed, in order to prevent the bolt from being snapped or threads from generating limit deformation in the process of applying pre-tightening force, only the strength of a screw rod is increased, but the effect is not very good. The bolt is already applied in engineering time, stress concentration at the threaded section is prevented, and stress distribution of the bolt is more uniform, so that pre-tightening force can be reliably applied to the bolt, and the failure probability of t