How to determine the source of bolt fracture

After understanding the fracture morphology of bolt products under various stresses, the next step is how to determine the source of fracture. Because the fracture source is the place where the bolt has the weakest performance or the most concentrated stress, it records the possible defects of the bolt from the raw material to the finished product, as well as information about the bolt's assembly and service. Through the analysis of the fracture source, the real cause of the fracture is obtained. Generally speaking, the following methods can be used to determine the fracture source:

1. For the fracture caused by the overload of the bolt, the fiber zone is the location of the fracture source. The fibrous zone with a circular ridge-like pattern always has the crack source at the innermost crater.

2. For brittle fractures, the radial or herringbone pattern on the fracture can be used to find the source of the fracture.

3. For the fatigue fracture, the source of the fracture can be found according to the convergence of the shell lines.

4. In many cases, the instantaneous fault zone on the fracture is easier to judge, and the source of the fracture is generally on the opposite side of the instantaneous fault zone. Therefore, this principle can be used to find the source of the fracture. (Guide: Restrictions on the use of commodity fasteners in pipe flanges)

The above is the most basic method to determine the source of fracture. In fact, no matter what kind of fracture is caused by the action of force, when determining the source of fracture, it must be analyzed according to the stress of the bolt and its performance organization. The resulting fracture can accurately determine the location of the fracture source! If a bolt breaks during assembly, we should understand the force of the bolt during assembly and its performance organization. If the bolt is manually twisted and assembled, it is obviously not affected by the impact force; if the bolt is used with a gun head For high-speed assembly, the bolt is also subject to instantaneous impact force. Therefore, the fracture of the bolt is obviously different in these two assembly methods. Because the force of bolts is very complicated during assembly and service, the fracture appearances presented are also ever-changing, but as long as the above methods are used in conjunction with the force analysis, any form of bolt fracture is not difficult to determine.

More related Shenzhen stamping factory industry news: