Galvanized steel pipe
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May I ask what standards are followed when welding galvanized steel pipes? Are there any standards? Should a second galvanizing be done?
Galvanized steel pipes are usually those with threads. If welding is required, it is similar to welding ordinary carbon steel. Generally, galvanizing is required again; in cases where the quantity is very small or removal is difficult, it is possible to discuss this with the owner and use a zinc-rich primer for spraying. But this is the most prone to corrosion and potential leakage point.
Galvanized steel pipes should preferably be connected using threads; even if anti-corrosion treatment is applied after welding on-site, the inner surface of the pipe cannot be treated. This is especially true for instrument air pipelines, where the galvanized layer that is damaged due to welding will block the instruments.
Galvanized steel pipes are generally not welded. Post-weld zinc supplementation is not very feasible. Threaded connections are generally used.
For welding, water-based media are generally used, such as the ballast water and sewage systems on ships. . .
Apply a zinc-rich primer, if the brush can reach inside.
It can be connected by flange coupling, clamping, etc., with each joint undergoing secondary galvanizing. For reference.
Galvanized pipes are generally connected using threads; welding is not recommended as it will damage the galvanizing layer. Moreover, welding produces a strong odor that is harmful to health, and there will also be many impurities both inside and outside the pipe!
It is usually threaded, with flange connections
In water pipeline design, galvanized steel pipes are used only for small diameters (≤DN50); these small pipes are connected by threading, while larger pipes use ungalvanized pipes.