Spiral Steel Pipe Anticorrosion Coating Performance

Spiral steel pipe anti-corrosion coating performance mainly has the impact resistance, flexural properties, wear resistance. On the impact strength, the twist with polyethylene plastic coating is better than the asphalt coating, and a good protective layer of polyethylene plastic rigid polyurethane foam coating toughness, which has good resistance to bending properties, but smaller mechanical strength, can not withstand the beat, hit, so pay attention gently, avoid collisions and reduce damage when loading and unloading. into heat-resistant coating temperature resistance and low temperature resistance, which is to determine the boundaries of the main transport medium temperature parameters, to ensure that the use of heat resistance temperature deformation, not flowing, do not accelerate the rate of aging, and the softening point related the low temperature to ensure that it stacked at low temperatures, transport and construction pull no cracks, no shedding. Asphalt coating temperature performance is poor, piped medium temperature does not exceed 80 , heat-resistant coating of polyethylene plastic twist with a certain degree depending on the heat-resistant primer, if primer poor temperature resistance, adhesion performance is poor, the upper limit is quite petroleum asphalt coating, foam, rigid polyurethane foam coating as a good insulation material, but also has good high temperature performance. Size asphalt coating adhesion to the tear surface coated steel pipe attached to the first layer of asphalt torn area filled bit qualified, which is a qualitative description, because of its thick and coated glass cloth wrapped, meaning no quantitative analysis large, the adhesion with time is not obvious; polyethylene plastic is cast with a tear-resistant coating adhesion capability represents the size usually 20N/cm; rigid polyurethane foam having the coating of insulation effect protective layer of plastic foam and polyethylene composition has a protective effect, foam adhesion and corrosion of steel and asphalt layer and coating of polyethylene plastic twist with no comparable tensile strength polyethylene plastic protective layer is greater than 20MPa, has good tensile strength, pressure resistance. Buried steel pipe corrosion is electrochemical corrosion, electrolyte ions in the environment only through the anti-corrosion coating of metal surfaces constituting the current reaches the circulation circuit to cause corrosion, and therefore the electrically insulating coating is very important, asphalt coating polyethylene plastic coating and twist with rigid polyurethane foam insulation resistance and resistance to corrosion layers are very high breakdown voltage, which can meet the coating of oil and gas gathering pipeline coating electrical insulation requirements. Pipeline transportation, laying and other processes will inevitably damage the coating, the underground due to soil electrolyte and applied cathodic protection potential role of the damaged coating will produce a new leak or produce loosening the drain point, all type of coating will have a certain degree peeling. Since the absorption of asphalt coating is relatively high, when used in a high water environment, the coating resistance decreases due to water absorption, cathodic protection current density is increased, the possibility of peeling of the coating caused by increased proliferation, and because oil bitumen coating on the steel surface treatment do not ask, descaling is not complete, but misses the potential scale is higher than steel pipe, steel pipe surface corrosion layer electrochemical corrosion damage at the anode becomes, the greater the volume of rust generated aggravated Tu peeling layer, loss of corrosion.