Galvanized tube steel is an alloy of iron and carbon that has been rolled into a tube shape — often round, square, or rectangular — and then coated with zinc. Steel tubing is generally galvanized in one of two ways. It can be hot dipped, or passed through molten zinc, which forms a thick protective coating, or electroplated — passed through a solution of zinc with electrical current, which results in a thinner layer of zinc adhering to the steel.
When steel tubing is galvanized, the zinc that is adhered to it will corrode faster than the steel. This is beneficial because it acts to slow down the time that steel will take to rust. This process is actually electrochemical in nature, with zinc having a greater electronegativity than steel. When zinc is applied to steel with the knowledge that it will corrode faster, yet reduce its corrosion time, the zinc is referred to as a sacrificial anode.
This metal tubing is used in a variety of construction settings. One common use of galvanized tube steel sections is as interior framing members in all types of building construction. For interior use, electroplated, or electrogalvanized steel can be used. Since the layer of zinc on this type of coated steel is thinner, it is generally not used where it will be exposed to outside elements.
Hot dipped galvanized tube steel is typically the product of choice for outdoor structural applications. This kind of tubing is often utilized in the construction of carports, playground equipment, farm buildings, awnings, canopies, and trailers. It can be coated with a baked enamel finish to give additional protection from corrosion.
Advantages of using galvanized tube steel in construction are many. It is very strong. Consequently, less of it is needed to frame a building than if the same building were framed with wood. It also generally weighs less than wood. This usually means that a building will not have to be engineered for as much load, or weight, which often cuts down construction expenses. Other benefits of metal tubing include its rot resistance, fire resistance, and the fact that it will not split or warp.
Galvanized tube steel is also sometimes used for interior construction of automobiles. The steel gives the car frame its strength, while the fact that it is galvanized protects against corrosion. In addition, galvanized steel plate is sometimes used to make automobile bodies. This metal plate, along with the painted finish, helps delay rusting of the car’s body.