The characteristics of large construction machinery and equipment are: when the mechanical equipment is in working state, it is subjected to very large impact load, resulting in extremely strong high-frequency vibration. Under this high-frequency impact vibration, ordinary bolts and nuts will loosen and fall off. The most commonly used and valued nut is the nut. Nut is a part used for fastening together with bolt or screw. It is a component that must be used in all mechanical equipment industries. If its quality, fastening force and service life are not qualified, the mechanical equipment will become loose, resulting in damage or even scrapping, resulting in huge losses for mechanical enterprises. It is very important to select a nut with excellent quality and first-class anti loosening effect. Most nuts in the general market should be used with washers. In the machinery manufacturing industry, they are used under high normal temperature, atmospheric pressure and high vibration. Under such circumstances, the anti loosening effect will decrease significantly, loosen or even break. In order to prevent fastener failure, some use preset torque nuts, some use flattened nuts, and others use chemical gluing. However, these anti loosening methods are rigid anti loosening methods, which do not completely solve the essential problem of loosening. In essence, these anti loosening methods only delay the time of thread loosening, and the loosening of threaded connection is inevitable.