Why Did Your Bolt Suddenly Break?

Reasons for bolt breakage:

1.the quality of the bolts

2.the strength of the bolt

3.pretightening torque of bolts

4.Fatigue strength of bolts

Unqualified materials, unqualified heat treatment, unqualified product manufacturing, unreasonable bolt selection, harsh use environment, etc. all have a direct impact. When these conditions are all standardized, most bolt breakage occurs due to looseness. Because the situation of loosening and breaking of bolts is roughly the same as that of fatigue fracture. Finally, we can always find the reason from the fatigue strength. In fact, the fatigue strength is so great that we cannot imagine that the fatigue strength of the bolts is not used at all during use.

Causes of damage to threaded fasteners are loosening:

After the threaded fasteners are loosened, a huge kinetic energy mv2 is generated. This huge kinetic energy directly acts on the fasteners and equipment, causing damage to the fasteners. After the fasteners are damaged, the equipment cannot work under normal conditions, further causing Equipment damage. When fasteners are subjected to axial force, the threads are damaged and the bolts are pulled apart. When fasteners are subjected to radial force, the bolts are sheared and the bolt holes are made into ovals. Choosing a thread anti-loosening method with excellent anti-loosening effect is the fundamental solution to the problem.

Loosening of threaded fasteners has nothing to do with the fatigue strength of the bolt:

Threaded fasteners can be loosened only a hundred times in a transverse vibration test, but they need to be vibrated repeatedly a million times in a fatigue strength test. In other words, the threaded fastener becomes loose when it uses one ten thousandth of its fatigue strength. We only use one ten thousandth of its maximum capacity, so the loosening of the threaded fastener is not due to the fatigue strength of the bolt.