Difficultiesof anticorrosion in Flange connection
Corrosion prevention of flange part of pipeline has always been a technical problem. Pipes and equipment are arranged in the open air and installed on the ground. Coating is used to prevent corrosion, which requires good adhesion with metal surface, waterproof and atmospheric corrosion resistance, UV aging resistance and weather resistance. The coating composition of process pipeline is generally as follows: epoxy zinc-rich primer (bottom layer, thickness ≥ 80 μ m)-epoxy cloud iron antirust paint (middle layer, thickness ≥ 140 μ m)-fluorocarbon topcoat (top layer, thickness ≥ 100 μ m), the total thickness of coating should be ≥ 320 μ m. According to the requirements of anticorrosion construction code, the rust removal quality of anticorrosive coating is required to reach Sa2.5 grade before painting, but in the flange joint part, especially in the clearance of flange, because it is difficult to clean up the grease dirt on the surface and gap of the joint, the rust removal quality is often difficult to meet the requirements of the standard specification, so the anticorrosive coating coated is easy to fall off and can not play an anti-corrosion effect.