Surface Pretreatment:

Before surface rust removal on piping components, loose rust and paint scales should be removed, as well as debris and mud. The rust removal grade should meet the rust level and rust removal grade of the steel surface before coating, as specified by GB/T8923, reaching the St2 grade.

After surface treatment of steel, apply AC paste if directly exposed to prevent rust. Form a certain thickness of oil layer. If the surface remains wet or underwater, it is mandatory to apply AC paste.

Filled AC Putty (Mud)

For irregularly shaped workpieces with indentations such as valves, flanges, pipe joints, and bolts, it is advisable to use AC putty to create a smooth outer contour, to prevent bridging or voids when wrapping with AC tape later.

AC oil tape winding

Helically wrapped with 55% overlap to achieve double protection. The overlap length of the AC oil tape at the start and end should be no less than 100mm. Press and hold the start end tightly during wrapping to prevent it from curling. Maintain a consistent tension during the wrapping process to flatten any wrinkles and gaps, ensuring the tape adheres closely to the workpiece surface. Avoid extending the tape too long.

AC External Protection Tape:

An additional self-adhesive AC outer protective strip is spiral wrapped around the AC oil tape, with a lap width of 55%. The lap length at the start and end of the protective strip should be no less than 100mm. The tape should be pressed down during wrapping to prevent it from curling up. A consistent tension should be maintained throughout the wrapping process. The wrapping should be as smooth as possible.

Quality Inspection:

Whether factory prefabricated or on-site construction, quality inspections should be conducted. Appearance inspection of the anti-corrosion coating

Coating Appearance Inspection

Conduct a 100% visual inspection of the protective coating; there should be no missing packages, no damage, and it should be as smooth as possible.

Thickness Inspection:

Measure the coating thickness of K pipeline using the non-destructive measurement method (magnetic method) as specified in SY/T0066. Randomly inspect three locations; if the thickness is found to be non-compliant, double the inspection; if still non-compliant, it is deemed不合格. The non-compliant sections should be repaired.

Electrical Spark Leak Detection

Corrosion-resistant coatings for on-site construction in dry environments should be subjected to an electrical spark leak test, and any leaks found should be repaired promptly. The leak test voltage is 5000V.

Backfill:

Fill with fine sand or fine earth, and prevent sharp objects in the backfill from damaging the protective coating.