1.What are the core advantages of galvanized steel pipes in water supply projects?
Excellent corrosion resistance
The galvanized layer protects the steel pipe substrate through the "sacrificial anode" effect: when the pipe surface is damaged, the zinc corrodes first, forming a dense zinc oxide or zinc hydroxide protective film, delaying the rust of the steel pipe.
High strength and pressure resistance
Galvanized steel pipes are based on low-carbon steel, with a nominal pressure of up to 1.6MPa. They can withstand the stress caused by soil backfill pressure, water flow impact and temperature changes, and are not easy to deform or break.
Convenient installation
Flexible connection method: supports threaded connection, flange connection or groove connection, simple on-site processing, no need for complex welding equipment;
Moderate weight: lighter than cast iron pipes, low transportation and hoisting costs, especially suitable for narrow construction sites (such as urban underground pipeline reconstruction).
2.What are the main application scenarios?
Municipal tap water projects: water supply mains in urban main roads and branch pipes for residential areas, which need to take into account both pressure resistance and hygiene;
Industrial circulating water systems: such as cooling water pipelines in power plants and chemical plants;
Temporary water supply projects: such as temporary water supply at construction sites and emergency water supply (quick installation and disassembly, and reusable);
Water supply in low temperature environments: In environments above -20℃, the frost resistance is better than that of plastic pipes (not easy to rupture due to frost heave).
3.What are the limitations of galvanized steel pipes in water supply projects?
Highly corrosive water: such as acidic water, high-chlorine water or water containing sulfide, the zinc layer will corrode quickly, and plastic-lined galvanized pipes or stainless steel pipes need to be used instead;
Long-term high-temperature transportation of drinking water: When the water temperature is greater than 60°C, the zinc layer may dissolve faster, causing the zinc content in the water to exceed the standard, affecting drinking safety;
High-precision clean water system: such as ultrapure water transportation in the pharmaceutical and electronics industries, the zinc layer may fall off and produce impurities, and seamless stainless steel pipes are required.
4.What are the anti-corrosion and protection measures?
Double internal and external corrosion protection: In addition to the galvanized outer wall, the inner wall can be lined with cement mortar or epoxy resin coating to enhance the adaptability to water quality;
Buried pipeline protection: When the soil is highly corrosive, it is necessary to strengthen the anti-corrosion layer + sacrificial anode cathodic protection to extend the service life to more than 30 years;
Regular maintenance: Check the corrosion condition of the pipeline every 3-5 years, and promptly apply cold-spray zinc paint with a zinc content of ≥95% to the exposed or damaged zinc layer.
5.What are the connection quality control requirements?
Threaded connection: Use hemp or polytetrafluoroethylene tape to seal, avoid over-tightening and damage to the zinc layer; apply anti-rust paint to exposed threads;
Flange connection: Use rubber or asbestos gaskets (to avoid electrochemical corrosion caused by metal contact), and the bolts need to be galvanized;
Groove connection: The groove depth needs to match the pipe diameter to ensure that the sealing ring fits completely, and the pressure test is carried out.