High strength bolt tightening inspection system

High strength bolt tightening inspection system

1. After the final tightening of high-strength bolts, on-site technical personnel should promptly issue a final tightening inspection notice to the laboratory, and the laboratory must make all preparations before the final tightening inspection.

2. The on-site final tightening inspection must be completed within 4 hours to 24 hours after the completion of high bolt tightening. The final tightening inspection will be carried out by the testing personnel in the work area, and on-site cooperation work will be done well.

3. Before inspection, the torque wrench must be calibrated, and its torque error should not exceed ± 3% of the torque value used.

4. The initial tightening inspection is carried out by on-site technical personnel. Use a small hammer with a weight of approximately 0.3KG to strike the opposite side of the nut and tightly grip the other side of the nut with your fingers for inspection. If the vibration is significant, it is considered unqualified and initial tightening should be carried out again.

5. Before the final tightening inspection, on-site technicians should observe all high-strength bolt connections after the final tightening, and check the relative positions of bolts and nuts marked with paint rings after the initial tightening to check for any missing final tightening.

6. The final tightening inspection frequency must strictly follow the specification requirements. At the connection of the main truss beam, longitudinal beam, and crossbeam, 5% of the total number of high-strength bolt connections for each bolt group, but not less than 5 sets, and at least 1 set of tightening torque inspection shall be conducted for each node.

7. After final tightening, check the torque value of the nut, and the deviation should not exceed 10% of the torque value, otherwise it will not be qualified.

8. The proportion of unqualified bolts in the total number of spot checks at each node shall not exceed 20%. If it exceeds 20%, continue to conduct spot checks until the cumulative pass rate reaches 80%.

9. When the tightening is insufficient, it should be supplemented in a timely manner. When the tightening is excessive, the bolts should be replaced and re tightened.

10. During the inspection process, the experimental personnel must make original records and file them in a timely manner.

11. After the inspection is completed, the laboratory should promptly release relevant data.