From the perspective of the coating temperature range, epoxy powder coating and polyurea anti-corrosion coating can be used normally in soil corrosion environments ranging from -30 °C or -25 °C to 100 °C, while the three-layer structure polyethylene The maximum service temperature of the anti-corrosion coating is 70 ℃. In terms of coating thickness, except for the two epoxy powder coatings, the thickness of the other three coatings are all above 1mm, which should be classified into the category of thick coatings.
One of the general items of the pipeline coating standard is the mechanical and physical properties of the coating, that is, the actual situation that may be encountered in the pipeline construction process, such as considering the bending of the pipeline after welding and hoisting the lower ditch during the construction of the long-distance pipeline. The low-temperature bending resistance index items are formulated according to different pipe diameters, the impact resistance items of the coating are determined by the collision damage caused by pipeline transportation and backfilling, the scratch resistance and scratch resistance of the coatings are determined by scratches and abrasions when the pipelines are traversed. Wear resistance, etc. From the perspective of these properties, no matter epoxy powder coating, three-layer structure or polyurea coating, they all have good performance, but in terms of coating thickness, three-layer polyethylene has the highest impact resistance value, while spraying The minimum impact resistance value of 14.7J for the polyurea protective coating is also excellent.
Since the coating of long-distance pipelines is mostly used in combination with cathodic protection, the design of pipeline coating indicators pays more attention to the anti-cathodic disbondment performance of the coating, thus setting up short-term and medium-term anti-cathodic disbondment projects, taking into account the use of long-distance pipelines. The temperature thus sets the high temperature cathodic disbondment project. From the index setting point of view, it is obvious that the anti-cathodic disbondment index of epoxy coating is higher, the maximum cathodic disbondment is 8.5mm at room temperature for 28d, and the maximum cathodic disbondment at high temperature is 6.5mm at 48h. The indicators of urea coating are relatively loose, 12mm and 15m respectively.
Post time: Oct-12-2022