Spiral Steel Pipe Anticorrosion

For three processes electrochemical corrosion of buried pipelines, such as the increase in pipe wall corrosion coating, loop resistance can be increased, reducing the corrosion current; external DC power supply, so that the soil pipe to cause the formation of cathodic protection negative potential can eliminate the yin and yang. potential difference, stopping fundamentally carried anode and cathode process, but once the anti-corrosion coating is damaged, exposed iron part will accelerate localized corrosion. Therefore anti-corrosion coating and cathodic protection is a combination of methods to rid the table of the economic and effective, it must adopt anti-corrosion coating cathodic protection must also be adopted. But for city gas system, because the underground pipe network intensive cathodic protection of pipelines to other large external power supply interference can cause its own benefit. Maintenance costs after the gas pipe network due to city gas pipeline network in the urban areas, put into operation after maintenance and overhaul difficulties and high costs, it should be appropriate to increase an investment in order to reduce the workload of routine maintenance after commissioning the pipeline due to the destruction of the output current process, the magnesium alloy sacrificial anode design life of the pipeline's life is best to use match, spiral pipe corrosion inhibiting method from the start of a process which, while using the ratio of the potential negative spiral spiral steel metal materials and sacrificial anode protection law does not appear connected to such a situation, so dry gas city gas pipe corrosion protection methods should be used with sacrificial anode corrosion coating combining For other non-trunk pipelines lower pressure, the anti-corrosion coating method is generally used directly. Currently buried gas pipeline external corrosion coating commonly used are mainly three PE composite structure. Epoxy powder (FBE), coal tar enamel. Coal tar epoxy and PE tape and other five. Neither wasted nor multi-increasing maintenance costs, but it should be noted that when the soil resistivity and high waters are protected through the pipeline, the sacrificial anode protection should not be used. has a different quality and cost of different antiseptic preservative methods, different pressures should be protected in accordance with spiral welded pipe Different purposes and different environments in which different gas and transportation, comprehensive account of the cost of corrosion and corrosion protection method in consideration of economic rationality should pay attention to two points. When the spiral pipe corrosion, hardness index is an issue to consider.