Steel structure hexagon bolts are divided into hexagon bolts and large hexagon bolts.
Hex bolts made of high-strength steel or bolts that require a large preload force are called high-strength bolts. It is mostly used for the connection of bridges, rails, high pressure and ultra high pressure equipment. The breakage of such bolts is mostly brittle fracture. High-strength bolts used on ultra-high pressure equipment require large pre-stresses to ensure the seal of the container.
The high-strength bolt exerts a pre-tensioning force and transmits the external force by friction. In addition to the high material strength, the high-strength bolt exerts a large pre-tension on the bolt, so that a pressing force is generated between the connecting members, so that the direction perpendicular to the screw is very large. Large friction, and pre-tension, anti-slip coefficient and steel type directly affect the bearing capacity of high-strength bolts. According to the characteristics of the force, it is divided into bearing type and friction type. The calculation methods are different. The hexagonal bolt connection has the advantages of simple construction, good performance, disassembly, fatigue resistance, and no looseness under dynamic load. It is a promising connection method. The hex bolts are tightened with a special wrench to create a large and controlled pre-tension of the bolt. Through the nut and the backing plate, the same amount of pre-stress is also applied to the connected parts. Under the pre-pressure, a large friction force will be generated along the surface of the connected member. Obviously, as long as the axial force is less than the frictional force, the member will not slip and the connection will not be damaged. This is the hexagonal bolt connection. principle. The hexagonal bolt connection is prevented from sliding against each other by the frictional force between the contact surfaces of the connecting members. In order to make the contact surface have sufficient friction, it is necessary to increase the clamping force of the member and increase the friction coefficient of the contact surface of the member. The clamping force between the components is achieved by applying a pre-tension to the bolts, so the bolts must be made of high-strength steel.
Large hexagon bolts are also steel bolts that are a high-strength bolt and a standard part. The fastening performance is better, and it is used for the steel structure and engineering to make the fastening effect. In general steel construction, the required steel structural bolts are 10.9 grade and are high strength steel structural bolts. Steel structural bolts are mainly used in steel structure engineering to connect the connection points of steel structural steel plates. The construction of large hexagon bolts must be tightened immediately after initial tightening. The impact bolts or torque adjustable electric wrenches are required for the initial tightening of steel structural bolts. The final tight steel structural bolts have strict requirements, and the final tight torsion shear type steel structural bolts must be Torsion-type electric wrenches must be used with torque-type electric wrenches. The large hexagonal steel structural bolts consist of one bolt, one nut and two washers.