Rust removal and anticorrosion engineering of steel structure building
Construction technology of rust removal and corrosion protection for steel structure roof (wall and indoor): rust removal → cleaning → painting and spraying of anti-corrosion primer → inspection and touch-up painting → painting and spraying of anti-corrosion surface.
1. Derusting process requirements: the base should be thoroughly cleaned and polished or sandblasted with special equipment. After derusting, there shall be no rust spots on the base, and oil stain, dust, iron sand and metal oxide shall be removed. After derusting, the primer must be sprayed for anticorrosion treatment within 6 hours. Before spraying, if the surface of the base steel is wet due to rain or other conditions, after the environment reaches the construction conditions, dry the surface moisture with dry compressed air and remove rust. After derusting, the steel surface reaches the derusting grade of Sa2.5, and the surface is cleaned with tools such as brushes before the next working procedure can be carried out. After rust removal, the steel surface presents metallic luster, and the rust spots and paint on the metal surface shall not be greater than 5% per square meter. If corrosion occurs before priming, the grinding requirements shall not be lowered to avoid reducing the roughness.
2. Cleaning process requirements: high-pressure cleaning equipment must be used to clean the surface of the base, and thoroughly clean the cracks, concave and convex parts and hidden corners of the base. The base surface must be solid and flat, and the uneven or cracked parts must be reinforced before construction; The base surface must be cleaned and free of dirt, floating dust, sundries, clear water, oil stains or loose objects. , and always pay attention to keep the base clean and hygienic.
3. Technological requirements for coating anticorrosive primer: Before construction, the base surface must be kept free of floating rust, wet marks, stagnant water and cleanliness, and construction is not allowed in rainy days. Use special equipment for high-pressure spraying for construction, and the construction materials must be free of precipitation. After strict inspection, the packaging barrel should be used as soon as possible on the day after opening the lid. Before use, the spraying materials must be evenly mixed with a special pulverizer to ensure that the special equipment for high-pressure spraying is not blocked during construction, and the spraying process must be even, without accumulation or omission.
4. Inspection of touch-up paint: Carefully inspect the corner, edge seam, horizontal lap, vertical lap, fan hole, pipes protruding from the roof, air conditioning pipes, joints between metal plate and parapet, screw fasteners (corners, C-beams, I-beams, trunking, ceiling suspenders, pipes) and other weak anti-corrosion links to ensure that all corners of edge seams are sprayed in place.
5. Technological requirements of anticorrosive topcoat: topcoat construction can only be carried out after the surface of primer is dry, and high-pressure spraying special equipment is used for construction. After construction, the anti-corrosion coating should be uniform in thickness and meet the design requirements; No defects such as falling off, accumulated cracks, warping, foaming, delamination, loose closure, etc. The construction shall ensure the seamless and comprehensive coverage of the whole base, and enter the maintenance period after the completion of the project, and no one shall enter the construction site.