1. Insertion Direction
The bolt insertion direction must be uniform, starting from the center of the structure and expanding symmetrically outwards.
For torque-shear bolts, the chamfered side of the washer should face the nut; for large hexagonal bolts, the chamfered side of the washer should face the bolt head.
2. Tightening Steps
Initial Tightening: Tighten with an impact wrench to 60%-80% of the standard axial force, and mark the bolt positions.
Final Tightening: For torque-shear bolts, remove the clips; for large hexagonal bolts, use the torque method or the angle method.
Sequence: Start from the center of the bolt group and expand symmetrically outwards to avoid localized stress concentration.
3. Precautions
Forcing bolts into the bolts is strictly prohibited. Any deviations in hole position must be corrected with a reamer and metal filings removed.
Bolts at the same node must be fully tightened on the same day to avoid omissions.
