How to deal with the white rust on the surface of galvanized steel pipe after being exposed to rain

First: The cause of alkali (white rust, black spots)
1. The formation principle of white rust
When galvanized steel pipes are tightly stacked and placed in humid air since there is no free-flowing air on the surface of the product, the surface of the zinc layer will undergo electrochemical corrosion to form white rust. Because the condensed water attached to the surface of the zinc layer merges with oxygen, carbon dioxide, hydrogen sulfide, sulfur dioxide, oxides, and other chemical gases, a corrosive aqueous solution will be produced and attached to the surface of the zinc layer to form an electrolyte, and this electrolyte and the zinc layer will produce electrochemical corrosion, thereby producing white dots of powdered substances (zinc oxide) white rust visible to the naked eye. The secondary and tertiary oxidation products of white rust form a local black appearance, which are collectively referred to as alkali-reversal phenomena.
2. The impact of white rust
Since the volume of metal zinc increases by 3 to 5 times when it is converted into zinc oxide or zinc hydroxide, the volume of white rust is larger, which makes the degree of white rust corrosion look much more serious than the actual situation, seriously affecting the appearance of the zinc layer, but they only cause a small loss of zinc on the surface.
3. Treatment of white rust
A large amount of white rust may appear on the surface of galvanized steel pipes, but the actual corrosion of the zinc layer is relatively mild. In most cases, the appearance of white rust does not indicate that the zinc layer has been severely damaged. After white rust occurs, the galvanized steel pipes should be spread out to make their surface dry quickly.
In summary, due to factors such as weather, transportation, and storage, the alkali-reversal phenomenon is common in galvanized steel pipes in summer. As long as the zinc layer after corrosion is higher than the standard value, it will not have any impact on the service life of the product.

Second: Precautions
1. All galvanized steel pipes will produce white rust in humid, high temperatures, poor air circulation, and corrosive environments. Products that are prone to white rust: angle steel, flat iron, square tube, round tube, and other tightly packaged and sealed products have water accumulation inside, and the weather is hot and humid, and the alkali-reversal phenomenon of galvanized steel pipes is prone to occur.
2. After arriving at the destination, the galvanized steel pipe should be stored in a warehouse with good air circulation, and should not be stacked in places with harmful gases and dust.
3. If slight white rust or spots appear on the surface, it should be immediately disassembled dried, and ventilated until the white rust turns into powder and then brushed off with a brush in time.
4. In a humid and hot environment, try to store indoors to keep ventilation and dry, and avoid direct contact with wet soil when stacking.
5. Galvanized steel pipes are not afraid of high temperature, humidity, or concentrated stacking, but they are afraid of all three at the same time, that is, concentrated stacking in a humid and hot environment. Only galvanized steel pipes that have been passivated are good.