Hot Dipped Galvanization is the process by which a steel part is physically dipped into a molten bath of zinc at a temperature of around 840°F. The zinc adheres to the steel part (in this case a trailer wheel) and completely coats the steel trailer wheel. The zinc then reacts with oxygen to form zinc oxide, and then reacts with carbon dioxide to form zinc carbonate. The result is a dull grey, anti-corrosive finish that protects the trailer rim from rust and corrosion. Trailer Wheels are commonly galvanized as it is more cost effective than stainless steel.
Galvanization forms a protective layer between the steel rim and the environment. Zinc is an electro-negative metal in comparison to the steel. This is an important characteristic of galvanized rims, because in the event that the galvanized surface is damaged and the steel rim is exposed; the coating can continue to protect the wheel up to 5mm in diameter through galvanic corrosion. Damaged areas greater than 5mm are not protected as much because the electron transfer rate decreases.
The Hot-Dipped Galvanization Process:
Tip: Don't Lick Your Galvanized Wheels! Lead is often added to the zinc to improve the fluidity of the zinc bath.