The raw material of seamless steel pipe is light, high strength, good tolerance, can withstand high internal pressure, sensitive in production and application, and can be used in messy or harsh geological conditions. However, there are disadvantages in the use process, mainly because the internal and external anti-corrosion treatment is more troublesome.
1. First of all, the problem of external wall corrosion. The quality of external wall corrosion directly affects the service life.
At present, the external anticorrosion of domestic steel pipes is mainly concealed. All steel pipes need to be reinforced or specially reinforced, and cathodic protection has been promoted in some areas.
Common anti-corrosion methods for exterior walls include petroleum pitch, epoxy coal pitch and other coatings, which are not easy to solidify at low temperatures, and there are many problems in the construction of on-site welded joints. In the past, chlorosulfonated polyethylene was used. Due to the large amount of solvent, it is easy to produce pinholes and cannot resist penetration. It is no longer used in some areas.
Cathodic protection has a good anti-corrosion effect, but due to the method of sacrificing anodes, anodes must be replaced regularly in future operations, which increases operating costs and operating expenses.
2. There are three commonly used treatment methods for the inner wall of seamless steel pipes: anti-corrosion paint, resin mortar, and cement mortar.
But these three methods have two problems: one is the bonding strength of the anti-corrosion layer and the steel pipe. Both anti-corrosion coatings and resin mortar require thorough derusting of the inner and outer walls of the steel pipe before construction, but this is difficult to achieve. Therefore, rust spots are the source of subsequent delamination, which constitutes corrosion and scaling. Second, most of the steel pipes are butt welded on site, and they are anticorrosive after welding. It can only be done manually, and the quality is not well controlled. For pipelines with small diameters, since personnel cannot enter the construction, they cannot be treated with anti-corrosion treatment, which also poses a hidden danger of future weld damage.
Tips: ASTM A53 covers seamless and welded steel pipe with nominal wall thickness. The surface condition is usually black and hot-dipped galvanized. ASTM A53 is produced mainly for pressure and mechanical applications, and is also used for transport of steam, water, gas line pipes. A53 ERW pipe is a typical carbon steel pipe(CS erw pipe).