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.

The tensile strength of a bolt refers to the maximum tensile force that the bolt can withstand before being broken in the axial direction. It is the critical value for the transition from uniform plastic deformation to locally concentrated plastic deformation, and it is also the maximum load under static tensile ability. The yield strength of a bolt refers to the phenomenon that the stress does not increase or fluctuates within a small range during the tensile test of the bolt, but the phenomenon of rapid increase in strain occurs.