I. Appearance Issues
Rough Surface: Tool marks and grinding marks left by improper machining will affect the thread fit accuracy.
Rust Spots: Corrosion caused by improper storage or use environment.
Burrs/Indentations: Indentations or thread defects on the hexagonal face or flange bottom surface.
II. Installation Issues
Flange End Face Not Perpendicular: A deviation exceeding 1-2mm (based on pipe diameter) will lead to poor sealing.
Flange Misalignment: Loose bolt holes or misaligned outer edges will affect bolt insertion.
Eccentric Gasket: The gasket is not in full contact with the flange sealing surface.
III. Bolt Issues
Inconsistent Specifications: Length and thickness do not match.
Incomplete Threading/Insufficient Tightening: Bolts are not fully tightened or are not properly tightened.
Inconsistent Installation Direction: Bolts are installed in the wrong direction.
IV. Sealing Issues
Damaged Sealing Surface: Damage will reduce sealing performance.
Media Leakage: Leaks discovered during pressure testing or operation must be addressed immediately. V. Corrosion Prevention Issues
Inadequate Surface Treatment: Insufficient corrosion prevention measures for bolts, nuts, and washers.
VI. Standardization Issues
Exposed Bolt Length: Should be controlled within 1-3 thread pitches.
Washer Usage: More than two washers are strictly prohibited on each sealing surface.
