1. Torque Compliance Verification: Use a torque wrench to check each bolt individually. The tightening torque of all bolts must meet the design standard, with errors within the allowable range, ensuring uniform and compliant preload.
2. Exposed Length Compliance: At least two complete threads must be exposed on the outer side of the nut. The total exposed length should be controlled within 0-3 thread pitches and must not be lower than the nut end face.
3. Gasket and Alignment Check: Observe that the gap around the flange is uniform and consistent. Confirm that the gasket center is within the flange flange edge, without any offset or extrusion.
4. Sealing Leakage Test: Apply soapy water to the flange connection area, pressurize the system, and observe. No bubbles emerging indicates that the sealing performance is qualified.
