High-strength bolts are one of our common fastening parts. Tightening is an important link that we value most during use, so many people will ask: How to tighten high-strength bolts? What are the methods for tightening high-strength bolts? This For a series of questions, China Standard Parts Network will give you the best answer based on years of experience.
1. Torque method
According to the proportional relationship between the torque M and the pre-tension force, the nut is preliminarily tightened with an ordinary wrench, and then screwed to the specified torque value with a special wrench that can display the torque value.
2. Corner method
A method determined according to the relationship between the rotation angle of the high-strength bolt and the pre-tension force of the bolt after the close contact between the slabs. When tightening, first use a short wrench to screw the nut to the non-rotating position, and then use a long wrench to screw the nut to the specified position to achieve pre-tension.
3. Unscrew the tail of the bolt
For torsional shear type high-strength bolts, this bolt has a special tail. When tightening, use a special wrench to hold the bolt and the bolt tail, one sleeve rotates forward, and the other sleeve reverses, and when the nut is tightened to a certain degree, the bolt tail is twisted off. Since the depth of the notch at the tail of the bolt is determined according to the relationship between the twisting torque and the pretensioning force, the corresponding pretensioning force value is reached when twisting off.