Does galvanized steel pipe need to be painted with antirust paint?

After the steel pipe is galvanized, the surface is covered with a layer of zinc coating, which separates the steel pipe from the atmosphere, avoiding the direct contact and corrosion of the steel to the atmosphere and is protected. The coating of zinc on the surface of the steel pipe, due to the strong chemical activity of zinc, forms a thin and dense layer of zinc carbonate in the air at normal temperature, and the zinc itself will not continue to be oxidized. Therefore, the galvanized pipe, whether it is the surface layer of zinc or the steel pipe itself, is protected from rust and does not need to be painted with anti-rust paint. Only when the galvanized layer is destroyed (such as steel pipe welding, coating burnt at the joint), the steel pipe is exposed to the air and loses the protection of the galvanized layer. At this time, it is necessary to make up the anti-rust paint.