The difference between high tensile bolts and ordinary bolts
High tensile bolts can withstand larger loads than ordinary bolts of the same specification. The material of ordinary bolts is made of Q235 (A3). The material of high-strength bolt 35 # steel or other high-quality materials is heat treated after being made to improve the strength. So what is the difference between high tensile bolts and ordinary bolts? Let ‘s take a look together.
From the perspective of raw materials: high tensile bolts are made of high-strength materials. The screws, nuts and washers of high tensile bolts are made of high-strength steel. Commonly used are 45 # steel, 40B steel, 20MnTiB steel, 35CrMoA, etc. Ordinary bolts are usually made of Q235 (equivalent to the previous A3) steel.
From the strength level: high tensile bolts are increasingly used. Two intensity levels of 8.8s and 10.9s are commonly used, with 10.9 being the most common. The strength level of ordinary bolts should be low, generally 4.4, 4.8, 5.6 and 8.8.
From the perspective of the force characteristics: high tensile bolts apply pre-tension and transmit external forces by friction. The ordinary bolt connection relies on the shear strength of the bolt and the bearing wall pressure to transmit the shear force. When the nut is tightened, the pre-tension force is very small, and its effect can be ignored. In addition to the high strength of the material, the high-strength bolt also exerts a lot on the bolt The pre-tensioning force causes a squeezing force between the connecting members, so that there is a large frictional force perpendicular to the screw direction, and the pre-tensioning force, the anti-slip coefficient and the type of steel all directly affect the bearing capacity of the high-strength bolt.
From the use point of view: the bolt connections of the main components of the building structure are generally connected by high tensile bolts. Ordinary bolts can be reused, and high tensile bolts cannot be reused. high tensile bolts are generally used for permanent connections. high tensile bolts are prestressed bolts. The friction type uses a torque wrench to apply the prescribed prestress, and the pressure type unscrews the torx head. Ordinary bolts have poor shear resistance and can be used in minor structural parts. Ordinary bolts need only be tightened.
More specifically: High-strength bolted connections have the advantages of simple construction, good mechanical properties, detachability, fatigue resistance, and no loosening under dynamic loads. They are promising connection methods. high tensile bolts use a special wrench to tighten the nut, which causes the bolt to generate a huge and controlled pretension. Through the nut and the backing plate, the same amount of preload is generated on the connected part.
The above is the introduction of the differences between high tensile bolts and ordinary bolts. I hope everyone will understand the differences between high tensile bolts and ordinary bolts, which will be helpful to everyone.
