As for the three electrochemical corrosion processes of ASTM A179 cold-drawn steel pipe, the main points of rust prevention are as follows:


First of all, for the urban gas system, due to the dense underground pipeline network, the interference of external power supply of cathodic protection to other cold-drawn steel pipes will cause their own interests and affect their families. This is not the case when cold-drawn steel pipe is connected to sacrificial anode protection with negative metal material and cold-drawn steel pipe. Therefore, anti-rust coating and sacrificial anode combination anti-rust method should be adopted for urban gas pipeline.




Secondly, there are three kinds of PE composite coatings commonly used in underground gas-cooled steel pipe at present, including epoxy resin powder (FBE), coal tar enamel, epoxy coal tar asphalt and PE tape. Three layers of PE composite structure, epoxy powder coating performance, so Europe and the United States is the main anti-rust coating for cold-drawn steel pipe. In China, three-layer PE composite structure Antirust Coatings are generally chosen for durability, maintenance cost and other comprehensive economic considerations.




Thirdly, in the method of sacrificial anode protection, the general purpose of magnesium alloy as sacrificial anode is to protect cold-drawn steel tubes. Due to the damage of output current, the design life of magnesium alloy sacrificial anode is best matched with the service life of cold-drawn steel pipe, which neither wastes nor increases the maintenance cost. However, it should be noted that sacrificial anode protection should not be used when the soil resistivity is too high and the protected cold-drawn steel pipe passes through the water.




Fourthly, different rust prevention methods have different quality and cost of rust prevention. According to the protection of cold-drawn steel tubes under different pressures, different uses, different environments and different gas transportation, comprehensive consideration should be given to rust prevention methods and cost. When considering the economic rationality, two points should be paid attention to: (1) investment in rust prevention of gas pipeline network construction and (2) maintenance cost after gas pipeline network construction. Because the city gas pipeline network is located in the urban area, the maintenance and maintenance cost is high after putting into operation, so the investment should be increased appropriately once to reduce the daily maintenance workload of cold-drawn steel pipe.