The difference between high strength bolt and ordinary bolt
Datetime:2016.10.09 From:HanDan HaoQiang Fastener Manufacturing Co.,Ltd
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High strength bolts are more bearable than ordinary bolts of the same specification. The material of common bolts is made of Q235 (A3). High strength bolt material 35 steel or other high quality material is made after heat treatment to improve the strength. The difference between the two is the difference in the strength of the material. From the raw material: High strength bolts are made of high strength materials. The screws, nuts and washers of high-strength bolts are made of high strength steel. They are commonly used in No. 45 steel, 40 boron steel and 20 manganese titanium boron steel. Common bolts are usually made of Q235 steel. From the level of strength: High strength bolts are used more and more widely. 8.8s and 10.9s are commonly used in two intensity grades, of which 10.9 are the majority. The strength grade of ordinary bolts is low, generally 4.4, 4.8, 5.6 and 8.8. In terms of the characteristics of the force: High strength bolts apply pre tension and friction force to transfer external force. The common bolt connects the shearing force of the bolt rod and the pressure of the hole wall to transfer the shear force. When the screw cap is tightened, the pretension is very small, and the influence can be ignored. The high strength bolt, in addition to the high strength of the material, also exerts a great pretension to the bolt to make the extrusion pressure between the connecting members, so that the vertical direction of the screw is very large. Friction, and pre tension, anti slip coefficient and type of steel directly affect the bearing capacity of high-strength bolts. According to the force characteristics, they are divided into pressure bearing type and friction type. The minimum specification M12 of high strength bolts is usually M16~M30, and the performance of super large bolts is unstable, so they should be carefully used in design.
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