After the galvanized steel mailbox is produced, the surface is generally not too flat. The residual impurities particles on the surface must be removed before galvanizing, so that the zinc layer will not fall off easily.

The iron oxide layer attached to the front surface of galvanized steel mailbox will also cause the galvanized layer to fall off. In the annealing furnace, the steel plate has not been completely converted into sponge-like pure iron, so the galvanized layer will be weak.
The aluminum content of the alloy layer in the raw materials of the galvanized steel mailbox is small, and a reasonable alloy layer that is decisive for the adhesion of the zinc layer is not formed. It is also possible that this alloy layer is destroyed by the overgrown iron-zinc alloy layer.
If the galvanized layer of the hot-dip galvanized steel mailbox falls off, the service life and performance of the galvanized steel mailbox will definitely be greatly reduced, because without the galvanized layer, the galvanized steel mailbox will rust and the service life will be shortened a lot. Therefore, to know what causes the zinc layer to fall off, targeted prevention is necessary.