How to repair an F-Style can after corrosion?
Nov 10, 2025
I. Corrosion Assessment and Surface Treatment
1. Corrosion Detection
Use an ultrasonic thickness gauge to measure the tank body in a grid pattern, focusing on welds, areas of liquid level fluctuation, and the bottom. If localized thinning exceeds 20% of the standard wall thickness or the remaining thickness is below the designed value, the can must be immediately decommissioned.
Analyze the corrosion products for chloride ions, sulfides, and other components to determine the type of corrosion (e.g., electrochemical corrosion, high-temperature sulfur corrosion, etc.).
2. Surface Treatment
Sandblast or polish to Sa 2.5 to expose the original metal color. Ensure the surface is free of oil, rust, and loose coatings.
If the can body is deformed (e.g., a concave bottom), weld reinforcement ribs (angle iron or profiles) to enhance structural stability.
II. Repair Material Selection
1. Polymer Composite Material
We recommend using 418 series nano-resin coating, which is resistant to high temperatures (≤200°C), acids, alkalis, and solvents, and is suitable for use in chloride-rich environments. Leaks can be sealed with 2211F plugging material before applying an anti-corrosion coating.
2. Fiberglass Lining
If long-term corrosion protection is required, vinyl resin fiberglass lining can be used. However, be aware that its poor thermal conductivity may affect tank efficiency.
III. Repair Process
1. Base Treatment
Chamfer weld cracks to a 120° angle. After cleaning, apply hot asphalt and fill with asphalt sand, compacting.
2. Coating Application
After the primer has dried, apply an anti-corrosion sheet (such as Fushi Blue), overlapping by 5mm and rolling to remove air bubbles. Curing with a UV lamp (≥3 minutes).
Finally, apply a top coat (0.2kg/m²). After curing, inspect for air bubbles and hollows. Repair any defects with primer.
IV. Special Scenario Treatment
High-Temperature Sulfur Corrosion: Use 0Cr13 stainless steel composite plates or aluminized materials to repair the tower and pipelines. Low-temperature sulfur-water corrosion: Catalytic cracking units must utilize 0Cr13 composite steel plates and ensure post-weld heat treatment.
5. Acceptance and Maintenance
After repair, airtightness testing is required, and coating hardness (Babcol hardness ≥ 50) and thickness are regularly monitored.
For buried tanks, upgrading to SF-type double-layer tanks and utilizing a vacuum leak detection system are recommended to enhance environmental safety.
