What is Galvanized Steel?

Galvanized steel is coated with zinc oxide to prevent rusting, since the chemical compound takes far longer to corrode than steel. It also changes the steel’s appearance, giving it a rugged look that some people prefer. All in all, galvanization makes the steel stronger and harder to scratch, so it’s ideal for outdoor use.

How does galvanization work?

Typically, manufacturers will dip the steel into molten zinc, which bonds itself to the steel like any other alloy would. This makes zinc more than just a protective coating, because it’s actually becoming part of the steel’s chemical composition. The interior may be steel, and the exterior may be zinc, but in between are gradient mixtures of steel and zinc that combine both metals’ properties. This dipping process is the most common form of galvanization, called hot-dipped galvanization. It’s also possible to spray zinc onto the steel, but this method creates a weaker layer of zinc.

Advantages

  • Rust Resistance: Iron in steel is incredibly prone to rusting, but zinc acts as a protective buffer between moisture, oxygen, and the steel.
  • Easy Inspection: It’s fairly simple to tell how strong a galvanized coating is, just by looking at it. There are also quick stress tests that can tell you how thick the zinc is.
  • Sacrificial Anode: This ensures that any damaged steel is protected by the surrounding zinc coating. It doesn’t matter if the steel section is completely exposed; the zinc will still corrode first.
  • Longer Life: With galvanization, a piece of industrial steel is expected to last more than 50 years in average environments, and can last over 20 years with severe water exposure. No maintenance required.

Disadvantages

  • Impractical to Dip Certain Items: Some steel pieces are too tiny or too huge to be hot-dipped, and it doesn’t make sense to galvanize them using other methods.
  • Zinc Can Be Temperamental: It’s important to take enough time to let galvanized steel cool down and settle in, so that the zinc doesn’t peel off. Galvanization isn’t nearly as effective if the zinc is not binding to the steel. The right coating thickness must be applied.