Superior hydraulic conditions for large diameter spiral steel pipe

　　Large diameter spiral steel pipe is not only anti-corrosion, but also anti-scaling. After actual observation, the cement mortar lining is even and smooth, covering all the concave and convex inner wall of spiral steel pipe and welding seam. The surface of cement mortar lining can form a layer of slippery putty containing manganese, which can reduce friction resistance. Its roughness coefficient is about 0.012, and API 5L Large Diameter Spiral Steel Pipe tends to decrease with the extension of service life. Therefore, cement mortar lining is conducive to improving the water delivery capacity of spiral steel pipe, saving energy and reducing consumption.

　　When spiral steel pipe needs internal corrosion protection, cement mortar lining should be considered first. Cement mortar lining separates the inner wall of spiral steel pipe from water or air to form a dense protective layer, thus inhibiting the oxidation, corrosion and scaling of the inner wall of spiral steel pipe. Compared with other anticorrosive coatings, cement mortar and spiral steel pipe inner wall have stronger bonding force, because the hydration of cement particles forms gel body, which produces bonding force on the inner wall of spiral steel pipe; when cement mortar hardens, the volume shrinks and tightens; when it adheres to the inner wall of spiral steel pipe, it produces friction force; when the inner wall of spiral steel pipe is uneven, it produces bonding force between cement mortar and steel pipe inner wall. Mechanical bite cooperation