What is the 7-Tank Process in Powder Coating? - The 7-Tank Process is a chemical pretreatment system used to clean and prepare metal surfaces—primarily mild steel—before applying powder coating. It removes oil, rust, and scale, and forms a phosphate layer that improves adhesion and enhances corrosion resistance. 1) Degreasing Removes oil, grease, and dirt from the surface. 2) Water Rinse 1 Rinses off degreasing solution. 3) Derusting / Pickling Removes rust, mill scale, and oxides using acidic chemicals. 4) Water Rinse 2 Cleans off the rust remover. 5) Surface Activation (optional) Sometimes used to prepare surface for better phosphating. 6) Phosphating Deposits a conversion coating (zinc or iron phosphate) that increases corrosion resistance and paint adhesion. 7) Final Rinse (with or without Passivation) Neutralizes remaining chemicals and may include a passivation agent to further prevent corrosion. #7-Tank Process in Powder Coating Manufacturer