2024-11-17
1 Bolt preload creates pressure between the contact surfaces of the connected parts. The greater the pressure between the contact surfaces, the greater the lateral force that can be transmitted. When the contact surface pressure is large enough, the lateral force is transmitted entirely by friction, and the bolts only bear the preload, no longer subject to shear stress and compressive stress, and the safety of the bolts is greatly increased.
2 When bolt connections are used for pressure pipes or pressure vessels, the bolts need to have sufficient preload to seal, and the total bolt preload cannot be less than the pressure of the fluid between the contact surfaces
3 Generally, bolt connections subject to fatigue loads are not allowed to have gaps in the connected parts. Once gaps are generated between the connected parts, the bolt tension will increase rapidly with the increase of the external tensile load
1. After bolt preload, it can prevent the opening of the connected parts from separating and improve the fatigue strength of the bolt connection;
2. Prevent the sliding of the connected parts, rely on friction to achieve the role of the connected parts resisting external loads, and avoid the bolts from being subjected to shear loads;
3. Prevent the internal pressure of the pressure vessel from leaking.
