Reasons for the fracture of hexagon bolts

The connecting rod bolts of diesel engines of hex bolt manufacturers are for one-time use and are not allowed to be reused.


The connecting rod bolts of diesel engines of hex bolt manufacturers are for one-time use and are not allowed to be reused. If the connecting rod bolts are repeatedly used, due to the large force and the elongated bolts, it is very easy to cause the bearing bush to roll and burn due to insufficient bolt tightening force; at the same time, due to insufficient tightening force, the matching clearance between the bearing bush and the crankshaft journal Increased, resulting in low oil pressure, resulting in excessive wear of bearing bushes and bush burning accidents.

Diesel engines are high-strength diesel engines, and the connecting rods are subject to greater impact load, much larger than ordinary diesel engines. Repeated use of connecting rod bolts can easily cause breakage, damage the engine cylinder block, and cause the engine to be scrapped. Although some units have replaced the connecting rod bolts, they also experienced fracture failures. Some engines suddenly broke the connecting rod bolts during operation.

The cause of the failure:① The tightening torque is too large during assembly and the force is uneven. Since there is no strict torque wrench used in the assembly, the specific tightening torque is not well understood, and the tighter the better. ② The connecting rods of diesel engines are divided into multiple levels. During maintenance, attention should be paid to not changing to connecting rods of different levels. If the connecting rod cover is not carefully messed up or installed incorrectly during maintenance, it will cause the coupling surface of the connecting rod big end to not fit tightly, and the connecting rod cover will loosen during engine operation, which will cause the connecting rod bolt to break.

If hex bolt manufacturers mess up the connecting rod cover during maintenance, it will inevitably lead to poor positioning of the serrations of the joint surface, which will easily cause the connecting rod cover to loosen during the engine work, and cause the connecting rod bolt to break.