Hot Dipped Galvanized vs Galvanized Steel
Electro zinc plating (or electroplating)
This method of galvanizing replaces the zinc bath with an electrolyte solution in which the steel is covered before treatment. While the steel rests in an electrolyte solution, an electric current is applied, converting zinc ions into zinc metal that adheres to the steel. This scientific process creates a thin layer of zinc. However, because the coating is so thin, the material is still susceptible to corrosion.
Annealing of galvanized layer
The process combines hot-dip galvanizing with annealing, a heat treatment that changes the material's microstructure to make it more durable. Therefore, alloyed galvanizing is still hot-dip plating, but by simultaneously annealing it, the resulting steel has more of a matte gray surface. The resulting coating is a combination of zinc and iron. It's great for manufacturing products or welding, but isn't the best choice for infrastructure projects that require stronger materials and corrosion protection.
Pre-galvanized
As the name suggests, pre-galvanizing is similar to hot-dip galvanizing, but is done as the first stage of production rather than the last. Most commonly used for rapid coating of sheet metal, the material is cleaned and treated before passing through a bath of molten zinc and then immediately backflushed. While this accelerated process does coat the material, the protective layer is cut during the manufacturing process. This leaves any areas where cuts occur uncoated and prone to rust and corrosion.
Reasons why we still recommend hot dip galvanizing compared to other methods:
Hot-dip galvanizing guarantees optimal corrosion protection
Hot dip galvanizing remains the best choice for ultimate corrosion protection. This is due to the thickness of the coating and how long it takes to apply the coating.
Other galvanizing methods do not allow the steel to bond with the zinc in the same way. This means that the resulting coating is not as thick or strong as that produced by hot-dip galvanizing. Without enough thickness to protect the material, the coating will be just as fragile and unable to withstand the test of time as any other protection option.
Another major reason why hot-dip galvanizing offers better corrosion protection is that the coating is applied during the fabrication process before the steel is installed. This means that any areas that were cut or damaged during installation will still have a protective coating. Other galvanizing methods, such as pre-galvanizing, coat the steel before it is cut and fabricated. This leaves any areas that were cut or damaged during installation susceptible to rust and corrosion.
Hot dip galvanizing is more economical in the long run
Hot dip galvanizing is one of the most economical methods of protecting steel. There are several reasons for this. By galvanizing the steel during or after fabrication, you save time shipping materials back and forth. You receive the material ready to cut without worrying about compromising the integrity of the product.
