Shiny, dull, or matte - differences in appearance are common, but does galvanising finish allows us to choose the desired final look?
Both of the photographs above were taken less than 24 hours after the completion of the galvanising process. By closely examining the dull grey finish, we can determine why it appears this way.
During the steel production process, silicone is added to some steel in varying quantities, resulting in the dull grey effect. The second photograph clearly illustrates that two different steels were welded together to create a lintel. The square hollow section appears predominantly grey, while the attached flat bar has a shiny appearance. Both pieces have undergone the same galvanising process at the same time, alongside the "shiny" steel depicted in the first picture.
Addressing the question of whether we can choose the appearance of the finish, the simple answer is no. We must, therefore, examine the distinction between the two finishes. Both are fully galvanised and offer the same level of corrosion protection. The dull grey finish, which has formed a zinc-iron alloy on the surface, is often thicker than shiny galvanised coatings and possesses greater hardness and abrasion resistance. Thus, disregarding aesthetics, it could be argued that the dull grey finish is superior.
Furthermore, it is worth noting that all galvanised steel will weather to a dull grey color when exposed to atmospheric conditions.