The high-strength nut pair after heat treatment is grade 10, and it is used in conjunction with the bolt of grade 10.9. There are certain differences between high-strength bolts and their general bolt calculation methods and bearing characteristics. Ordinary bolts directly bear the external bearing capacity, and the bearing capacity of high-strength nuts is used to increase the pre-tension force inside, and then the friction force produced by the contact area in the middle of the connector bears the external bearing capacity. The axial force of the high-strength nut is lower than the friction force, the connection will not be damaged, and the prefabricated component will not easily roll. It uses a common wrench to tighten the bolts, resulting in a very large and controllable preload. Using spacers and nuts, the pre-working pressure on the connection is the same. Under the action of prestressed tension, maijin is caused by very large friction along the connection surface. Therefore, the structure of the high-strength nut is relatively simple, and its physical properties are very good. It can be disassembled, relieves fatigue, and is not easy to loosen under dynamic bearing capacity. It is a very good connection method for development. The connection principle of high-strength nuts is like this. The connection of high-strength nuts is based on the friction between the contact areas to avoid rolling. In order to make the contact areas have sufficient friction, it is necessary to increase the clamping force and increase the friction coefficient of the contact areas. The previous locking force of the prefabricated component is realized by adding a pre-support force to the bolt, so the bolt must be made of high-strength steel. In the connection of high-strength bolts, the coefficient of friction has a great influence on the bearing. Experiments have shown that the coefficient of friction is mainly affected by the material of the parts and the form of the contact area. Sandblasting and steel brush cleaning are often used to remove the contact area of the components within the connection range to increase the friction coefficient of the contact area. Therefore, high-strength nuts are divided into two types: extrusion type and pressure type.