Galvanization is the process of coating steel and iron with zinc to protect the underlying metal from corrosion. This can be done by hot-dipping the steel or iron item into molten zinc or by dry-galvanizing iron or copper items by tumbling them with zinc powder. Hot-dip galvanizing is the most common method used by manufacturers to strengthen everything from building beams to yard furniture.
While both types of galvanizing can be done by the home hobbyist, it can be easier to get the equipment required for larger items as a manufacturing company because of both the size and expense of the items needed. Most companies will work with a galvanizing furnace manufacturer to build a system the size that they need for the items made such as the furnace, dip tanks and cooling racks. This allows a manufacturer to set up the size and design of the galvanizing system needed for the items being made without having to do the research and buying each item separately.
Preparing the surface of the steel or iron is a crucial step in hot-dip galvanization because if done incorrectly, then the finish will not last as long as needed or will have gaps. This step includes degreasing the item in a chemical or biological solution bath to remove oils and dirt from the surface, pickling it in acid to remove rust and milling dust, and then fluxing it to remove any remaining oxides and protect the surface with a thin layer of zinc to keep more oxides from forming before the galvanizing stage.
In this step of hot-dip galvanization, the item is lowered into a bath of molten zinc until it reaches the temperature of the bath. When it is raised again, it is drained, vibrated and sometimes centrifuged to get rid of excess zinc and then either dipped into a solution to cool and stop the metallurgical reaction or left on a rack to cool for the same purpose. Once it is cooled down, the item can be sent to the client for further manufacturing or as a finished product.
Galvanization is used on many products that you see and use daily from metal garbage cans to the beams in your office building or home. This makes the steel and iron more durable to the elements and is common in items designed to be used outdoors or in contact with water. You can find the equipment you need from manufacturing companies and can even get your whole system from the same one.