Compared with ordinary steel pipes,
seamless pipes (SMLS) can withstand higher pressures. Therefore, in industrial production, seamless steel pipes are used when pipes that need to withstand greater pressure. Some people call it "the tiny blood vessels in the industry", whether it is the manufacture of planes, ships, trains, or oil, gas, and water transportation, it is inseparable from him. Naturally, how to prevent corrosion of seamless steel pipes? What are the technical requirements? It is also a concern of many factories and Party A. Today we mainly talk about the anti-corrosion technical requirements of steel pipes.
Pipeline anticorrosion
The anti-corrosion of the steel pipe needs to be in accordance with the requirements of the drawings.
Outer wall construction process:
Pipe rust removal - primer - first coat - second coat - third coat
1. Pipe rust removal
Before priming, remove grease, ash, rust and iron oxide from the surface of the pipe. The quality standard of sandblasting and rust removal reaches Sa2.5 level.
2. Derusting the surface of the pipe
After the surface of the pipe is derusted, the primer should be applied, and the time interval between them should not exceed 8 hours. When the primer is applied, the base surface should be dry. The primer should be brushed evenly and fully, without any lumps or blistering, and should not be brushed within the range of 150~250mm at both ends of the tube.
3. Primer
After the primer surface is dry, apply the topcoat and wrap the glass cloth, and the time interval between the primer and the first topcoat should not exceed 24 hours.
4. Various material specifications
Epoxy coal tar tar coating adopts two-component, room temperature curing coating;
The glass fiber cloth is made of dry, dewaxed, untwisted, edge-sealed, medium alkali, and glass fiber cloth with a density of 10*12 pieces/cm~12*12 pieces/cm;
After the topcoat is painted, the glass fiber cloth should be wrapped immediately. The width of the edge of the glass fiber cloth is 30~40mm, and the lap length of the joint should not be less than 100mm. At the same time, the overlapped streets of each layer are staggered.
The oil penetration rate of glass fiber cloth reaches more than 95%, and no gaps larger than 50mm*50mm can appear. The pipe end needs to leave a stepped stubble of 150~250mm.
5. Pipe interface
The construction of the joint of the pipeline should be carried out after the welding pressure test is qualified. The old and new anti-corrosion edge pressing should not be less than 50mm, the lap length of the joint should not be less than 100mm, and the joint should be firmly and tightly bonded.
6. Outer wall of steel pipe
The coating requirements for the outer wall of the steel pipe: one bottom and two sides, one cloth and two sides, and the total thickness of the dry film is 400μm.
7. The inner wall of the steel pipe
Steel pipe inner wall coating mechanism: one bottom and three sides. The total dry film thickness is 300μm.
8. Quality inspection
After the external anti-corrosion construction is completed, it is necessary to carry out quality inspection in accordance with the design requirements or the corresponding requirements in the "Water Supply and Drainage Pipeline Engineering and Acceptance Specifications".
