​1. Due to the material of the bolt, if the material we choose is better, then the quality of our bolt will be better. If we choose poor materials, then our bolts will break to a certain extent. 2. The strength of the bolt is not high enough. If the pressure on the bolt is greater than the strength of the bolt, the bolt will easily break. Therefore, when we use bolts, it is best to know how strong the bolt can withstand, so that we can choose a bolt higher than this strength, and the possibility of bolt breakage will be much reduced. 3. As a result of unqualified manufacturing, many bolts will be produced unqualified, so there is no way to display the quality of standard bolts, which will lead to bolt fracture to a certain extent. After we produce the bolts, we must go through testing, so that we can guarantee that the bolts are qualified before being sold. This is also the most basic guarantee for consumers. 4. Due to the fatigue strength of the bolt. The most common factor for bolts to break is due to the fatigue strength of the bolts. There is no problem when we use the bolts at the beginning, but after the work of the object, there may be a certain amount of looseness. If the work is loosened, the fatigue strength of the bolt will increase. When the bolt is reached, the fatigue strength of the bolt will increase. The limit of the bearing range, then the bolt will also break.