What are the anti-loosening methods for external hexagon bolts? (1)

Why should hex bolts be loosened, is to make things better and longer and more useful. So, what are the anti-loosening methods for the connection of hexagon bolts? Let's talk about 5 kinds first:
1. Friction prevention
This is the most widely used anti-loosening method. In this method, a positive pressure that does not follow the external force is generated between the thread pairs, and a friction force that can restrain the relative rotation of the thread pair is generated. This positive pressure can be accomplished by pressing the thread pair axially or simultaneously in two directions. Such as elastic washers, double nuts, self-locking nuts and nylon insert lock nuts. This kind of anti-loosening method is more convenient to resist the disassembly of the nut, but in the environment of impact, oscillation and variable load, the preload force will decrease due to the loosening of the first end bolt. As the number of oscillations increases, the lost preload force is dull The increase in ground will eventually lead to loosening of the nut and failure of the threaded connection.
2. Permanent anti-loosening
Spot welding, riveting, bonding, etc. This method mostly destroys the threaded fasteners during disassembly and cannot be reused.