High-strength bolts are mainly used in steel structure engineering to connect the connecting points of steel structure steel plates. A very important feature of high-strength bolts is that they are limited to single use. They are generally used for connection. Repeated use of high-strength bolts is prohibited.
From the perspective of raw materials:
High-strength bolts are made of high-strength materials. The screws, nuts and washers of high-strength bolts are all made of high-strength steel, commonly used 45 steel, 40 boron steel, 20 manganese titanium boron steel. General bolts are usually made of Q235 steel.
From the perspective of intensity level:
High-strength bolts are increasingly widely used. Two strength levels of 8.8s and 10.9s are commonly used, of which 10.9 is the majority. Generally, the bolt strength level is lower, generally 4.4, 4.8, 5.6 and 8.8.
From the perspective of force characteristics:
High-strength bolts exert pre-tension and transmit external force by friction. Generally, the bolt connection relies on the shear resistance of the bolt and the pressure of the hole wall to transmit the shear force. The pretension force generated when the nut is tightened is small, and its effect can be ignored. In addition to the high material strength of the high-strength bolt, it also exerts a great deal on the bolt. The pre-tension force causes the squeezing force between the connecting members, so that there is a great friction force perpendicular to the screw direction, and the pre-tension force, the anti-slip coefficient and the steel variety directly affect the bearing capacity of the high-strength bolt.