How to improve the durability of ductile iron pipe network?

The durability of ductile iron pipe network can be improved from the aspects of improving the performance of the pipe itself, strengthening external protection, controlling construction quality and optimizing operation and maintenance. The specific methods are as follows:

Improve pipe performance

Optimized material: In the production of ductile iron pipe, the content of carbon, silicon, manganese and other basic elements is precisely controlled, so that the cast iron structure is more dense and uniform. At the same time, the appropriate amount of nickel, chromium, molybdenum and other alloying elements can enhance the strength, toughness and corrosion resistance of the pipe, such as nickel can improve the fatigue resistance of the pipe, molybdenum can improve the pitting resistance.

Improved manufacturing process: Advanced spheroidization and inoculation process is adopted to ensure that the graphite balls are small, round and evenly distributed, thereby improving the mechanical properties and corrosion resistance of the pipes. In addition, by precisely controlling casting temperature, speed and other parameters, casting defects, such as pores, sand holes, etc., are reduced to avoid these defects becoming corrosion sources or stress concentration points, affecting the durability of the pipe network.

Strengthen protective measures

Internal and external coating treatment

Inner coating: non-toxic, corrosion-resistant inner coating materials, such as epoxy resin, cement mortar, etc. The epoxy resin coating has good adhesion and chemical corrosion resistance, which can effectively isolate the contact between water and the inner wall of the pipe and prevent the corrosion of the water quality on the pipe. Cement mortar coating can not only prevent corrosion, but also smooth the inner wall and reduce the resistance of water flow.

Outer coating: Usually use asphalt paint, polyethylene coating, etc., as the outer coating. Asphalt paint has good water resistance and soil corrosion resistance. The polyethylene coating has high mechanical strength and weather resistance, which can protect the outer wall of the pipe from the erosion of water, oxygen and acid, alkali and salt in the external soil.

Cathodic protection: For the buried ductile iron pipe network, cathodic protection technology can be used. By installing sacrificial anode or impressed current cathodic protection device in the pipe network system, the surface of the pipe becomes the cathode, so as to inhibit the corrosion reaction of the pipe. For example, in areas where the soil is highly corrosive, the installation of a magnesium alloy sacrificial anode can effectively protect the ductile iron pipe from electrochemical corrosion.

Strict construction quality control

Pipeline installation: During the installation process, ensure that the pipeline is laid in accordance with the design requirements to avoid excessive bending, stretching or compression stress in the pipeline. At the same time, strictly control the installation quality of the pipeline interface, ensure that the interface is sealed well, and prevent the corrosion of the pipe caused by the leakage of the interface. For example, when installing the socket interface, ensure that the rubber ring is installed in place and the interface gap is uniform.

Foundation treatment: Do a good job of pipeline foundation treatment, according to the geological conditions to choose the appropriate foundation form, such as sand cushion foundation, concrete foundation, etc. Ensure that the foundation has sufficient bearing capacity and stability to prevent pipeline rupture or interface damage due to uneven settlement of the foundation, affecting the durability of the pipe network.

Optimized operation and maintenance

Water quality management: For the pipeline network of water transmission, the water quality should be strictly controlled to ensure that the water quality meets the relevant standards. Through softening, desalting, disinfection and other treatment processes, the content of calcium and magnesium ions in water is reduced, and corrosive substances such as dissolved oxygen and hydrogen sulfide are removed to reduce the corrosion of pipes.

Regular inspection and maintenance: Establish a regular pipe network inspection system, and use ultrasonic detection, magnetic flux leakage detection and other technical means to detect the wall thickness, corrosion and interface status of the pipeline. Timely detection and treatment of pipeline problems, such as the repair coating treatment of slightly corroded parts, the replacement of seriously damaged pipeline sections, in order to extend the service life of the pipe network.