1. The specifications and technical conditions of the connection pair of high-strength large hexagon head bolts should meet the design requirements and the current national standard "Technical requirements for high-strength large hexagon head bolts, large hexagon nuts and washers for steel structures."
Inspection method: inspect the quality certificate and factory inspection report batch by batch.
The inspection content includes that the material performance level of high-strength large hexagon head bolts, nuts, and washers must meet the requirements of GB 3633-83.
2. Anti-slip coefficient of high-strength bolt connection surface. Must meet design requirements.
Inspection method: check the anti-slip coefficient test report of the component processing unit, and check the re-inspection report of the anti-slip coefficient of the construction site. The test pieces at the construction site should be produced at the same time as the friction surface of the steel component and stored under the same environmental conditions to ensure the reliability of the test data. The friction coefficient test pieces are generally made into three groups, and the average value is taken.
3. The torque coefficient of the high-strength large hexagon bolt connection pair should be re-examined, and the result should comply with the current national standard "Technical conditions for high-strength large hexagon bolts, large hexagon nuts and washers for steel structures."
Inspection method: check the torque coefficient re-inspection report. The bolts for re-inspection shall be randomly selected from the bolt batches to be installed at the construction site. Each batch shall select 8 sets of connection pairs for re-inspection.
4. The surface of the friction surface of the high-strength large hexagon head bolts should be smooth, free of flash, burrs, welding spatter, welding scars, oxide scale, dirt and unnecessary paint.
Inspection method: observe and inspect.
5. The torque wrench used to fasten high-strength large hexagon head bolts should be calibrated regularly. The final tightening can only be carried out after the initial tightening of the bolts meets the requirements of the current national standard "Code for Construction and Acceptance of Steel Structure Engineering" (GB50205?5).
Inspection method, check the torque wrench calibration record and bolt construction record.
6. High-strength large hexagon head bolts should be freely inserted into the bolt holes, and not forcibly knocked.
Inspection method: observe and inspect.