Steel pipe is the most widely used gas pipe project. Its main advantages are: high strength, good toughness, bearing stress, impact resistance and tight, good plasticity, easy welding and thermal processing, the wall thickness is thinner, saving metal. But its poor corrosion resistance need to have proper anti-corrosion measures. Spiral steel pipe with a coil, low cost compared with steel rolling straight seam steel pipe. Moreover, spiral weld lines formed on the tube evenly than a straight seam pipe, weld avoid the main stress direction. So spiral in the city gas distribution pipe network still has some application.
City gas pipeline including gas transmission mains, distribution pipes, tubes and indoor users to introduce gas pipelines, each pipeline has a different purpose. Different pressure gas transmission, can be divided into low, medium, high-pressure and high pressure. Generally, the higher the pressure pipe, the greater the likelihood of the pipe leak, the pipeline with the higher quality requirements; but with a higher pressure, it is possible to reduce the initial investment in the entire network. Different purposes, different pressures and different diameter pipes, they must have different materials and different processes. City gas pipeline network, the high-pressure, high-pressure gas transmission pipelines and mains are generally used steel pipe, steel pipe, but there are also types of selection problems. In recent years, spiral steel pipe is widely used.
For the city gas system, due to the underground pipe network intensive, cathodic protection of external power supply to other pipeline interference, can cause its own benefit. The use of negative potential than steel metal materials and steel sacrificial anode protection law does not appear connected to such cases, therefore, city gas gas transmission trunk should be corrosion anti-corrosion coating and sacrificial anode method of combining.