At present, the safety of threaded connection in the manufacturing, production and maintenance of aerospace engines has been highly valued. Especially for self-locking nuts, because of their good shock resistance, loosening resistance and reusability, they have become a widely used thread in the aviation industry. Connect the components. The self-locking nut uses plastic deformation to form friction on the thread pair to prevent the thread from loosening. However, the self-locking torque between the thread pair will gradually decrease during repeated use, especially in the case of engine impact or significant load changes obvious.

Hydrogen embrittlement fracture of bolts is a common form of failure. Because hydrogen embrittlement fracture is delayed and concealed, the damage it brings is much greater than the damage caused by other fractures. Since this century, hydrogen embrittlement fractures of alloy steel bolts have been commonplace, seriously hindering the normal development order of aerospace models, and have reached the level of "talking about hydrogen discoloration". In order to enable more scientific and technical personnel to understand the mechanism of hydrogen embrittlement, grasp the law of hydrogen embrittlement of bolts, and effectively prevent the occurrence of hydrogen embrittlement of bolts, the results of these studies are now written and introduced for readers' reference.