高強螺栓可分為扭剪型和大六角型兩種，國標扭剪型高強螺栓為M16、M20、M22、M24四種，現在也有非國標的M27、M30兩種;國標大六角高強螺栓為M16、M20、M22、M24、M27、M30等幾種。一般的對于高強螺栓的緊固都要先初緊再終緊，而且每步都需要有嚴格的扭矩要求。大六角高強螺栓的初緊和終緊都必須使用定扭矩扳手。
High-strength bolts can be divided into two types: torsional shear type and large hexagon type. The national standard torsional shear type high-strength bolts are M16, M20, M22 and M24, and now there are also two types of non-national standard M27 and M30; National standard large hexagon high-strength bolts are M16, M20, M22, M24, M27, M30, etc. Generally, the high-strength bolts should be tightened first and then finally, and each step should have strict torque requirements. Fixed torque wrench must be used for initial and final tightening of large hexagon high-strength bolts.
定扭矩電動扳手的使用:
Use of fixed torque electric wrench:
定扭矩電動扳手既可初緊又可終緊，它的使用是先調節(jié)扭矩，再緊固螺栓。
The fixed torque electric wrench can be used for both initial and final tightening. Its use is to adjust the torque first and then tighten the bolts.
