In view of the three processes of electrochemical corrosion of buried pipelines, the anticorrosion method of polyurethane insulated steel pipes should also start from restraining one of them. Therefore, the combination of anti-corrosion coating and cathode maintenance is an economical and useful method. Because it is damaged in the process of output current, the service life of the magnesium alloy anode is best matched with the service life of the pipeline, which is neither extravagant nor expensive.
Different anti-corrosion methods have different anticorrosion quality and cost. The anticorrosion method and cost should be considered according to the different pressure, different use, different environment and different gas transported. When the flattening amount is 50 mm, the cracks are gradually added to the whole pipe section at the edge. According to the test results, when the flattening amount is 1% of the pipe diameter, the "hairy" cracks occur. When the flattening amount is 6-9%, the mortar coating begins to crack and falls off when reaching 30% of the pipe diameter. This is not allowed to happen in construction.
It is common for polyurethane thermal insulation steel pipe to deform and flatten under external pressure. However, it is very difficult to peel the mortar from the pipe wall. On the steel pipe with diameter of DN800 mm and wall thickness of 7.1 mm, one meter long pipe section is cut off and coated with 11 mm thick mortar coating. When the flattening amount is 7-8 mm, hairy cracks can be seen. According to the measurement, the minimum flattening is 15 mm on the pipe of DN 100 and 21 mm on the pipe of DN 1800. It can be seen that with the increase of pipe diameter, the flattening amount of cracks will also increase. The cement mortar fabric has the following obvious advantages: it can avoid the corrosion and scale on the inner wall of the pipeline, keep the pipeline in excellent water delivery condition for a long time, and the friction coefficient is small.
There are two ways to construct cement mortar. One is centrifugation on the ground. It is suitable for lining construction of pipes with diameter below dn400. It is the underground spraying method, which is mainly applicable to the underground anti-corrosion construction of pipes with diameter above DN700. Because of the barrier of the fabric coating, the water does not touch the metal pipe, which guarantees the water quality.
The inner wall of the pipeline is anticorrosive by cement mortar, which avoids the corrosion perforation and prolongs the service life of the pipeline. The material selection of the cement mortar coating is convenient, the construction period is short, the anti-corrosion effect is good, and the cost of the pipeline project is reduced. In view of the above advantages of cement mortar, its anti-corrosion function and economy are recognized by more and more engineering and technical departments at home and abroad. Domestic large and medium-sized cities promote the use of cement mortar as the primary receiving point of internal corrosion protection of water supply metal pipes. The state has also formulated the standard and quality standard of cement mortar fabric.
With the brief summary of polyurethane insulated steel pipe manufacturers, we hope to help our customers. If you have any questions or seek help, please click our website: https://www.sdhpgy.com Or call consultation, we will try our best to solve it for you
