The length of high strength bolt connection must be strictly controlled

High strength bolts exert pre tension and transmit external force by friction.

The shear force of ordinary bolt connection is transmitted by the shear resistance of bolt rod and the pressure bearing of hole wall. When tightening the nut, the pretension is very small, and its influence can be ignored. In addition to its high material strength, the high-strength bolt also exerts a large pre tension force on the bolt, so that there is a great friction force perpendicular to the screw direction The type of steel directly affects the bearing capacity of high strength bolts.

According to the stress characteristics, it can be divided into pressure bearing type and friction type. The minimum specification of high-strength bolt is M12, which is usually m16-m30. The performance of super large bolt is unstable, so it should be used carefully in design.

High strength bolt refers to the grade of bolt, hard bottom and other performance is relatively strong, also known as high strength bolt. Generally, it refers to 8.8 or above. For example, 10.9 grade bolts and 12.9 grade bolts are of high hardness and torsion performance

Length calculation of high strength bolt

The length of high strength bolt connection must be strictly controlled. The length of torsional shear type high-strength bolt is the length from the lower bearing surface of the screw head to the notch of the screw tail; for the high-strength hexagon head bolt, the thickness of a washer should be added,