High strength bolt tightening method
High strength bolts are a common fastening part and tightening them is one of the most important aspects we look for in the process. How to tighten high strength bolts? What are the methods of tightening high strength bolts? Today to give you the answer to this series of questions.
1、Torque method
According to the relationship between torque M and pretension proportional, first use an ordinary spanner to tighten the nut initially, and then use a special spanner that can display the torque value to tighten to the specified torque value.
2、Corner method
According to the close contact between the plates, the rotation angle of the high-strength bolts is determined in proportion to the pre-tension of the bolts. When fastening, first use a short spanner to screw the nut to a position that does not rotate, and then use a long spanner to screw the nut to the specified position to achieve the pre-tension.
3、Twist off the end of the bolt
For torsion-shear type high-strength bolts, which have a special tail. When tightening, a special spanner is used to hold the bolt and the tail of the bolt, one sleeve is turned positively and the other sleeve is reversed, and when the nut is tightened to a certain extent, the tail of the bolt is broken. As the depth of the groove in the tail of the bolt is determined by the relationship between the breaking torque and the preload tension, the corresponding preload value is reached when the bolt is broken.
