Difference between high strength bolt and common bolt

From the perspective of raw materials:

High strength bolts are made of high strength materials. The screw, nut and washer of high strength bolt are made of high strength steel. 45 steel, 40 boron steel and 20 manganese titanium boron steel are commonly used. Ordinary bolts are usually made of Q235 steel.

In terms of strength grade:

High strength bolts are widely used. 8 s and 10.9 s are commonly used, of which 10.9 is the most. Ordinary bolt strength

The degree level is low, generally 4.4, 4.8, 5.6 and 8.8.

According to the mechanical characteristics:

High strength bolts exert pre tension and transmit external force by friction. The shear force is transmitted by the shear resistance of bolt rod and the pressure bearing of hole wall

In addition to the material strength of high strength bolt, the material strength is very high

In addition, a large pre tension force is applied to the bolt, which causes extrusion force between the connecting members, thus causing great friction in the direction perpendicular to the screw

Friction force, pre tension, anti slip coefficient and steel type directly affect 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, commonly used

M16 ~ M30, the performance of super large bolt is unstable, so it should be used carefully in design.