Galvanized steel is considered a ferrous metal. This material is steel that has been coated with a layer of zinc to provide protection against corrosion. The underlying steel material determines the metal’s fundamental classification. This combination provides the high strength of steel with the extended lifespan afforded by the sacrificial zinc coating.
Understanding Ferrous and Non-Ferrous Metals
Metals are broadly categorized into two groups based on their chemical makeup: ferrous and non-ferrous. The defining factor for a metal to be considered ferrous is the presence of iron, symbolized as Fe, as its main constituent element. These metals typically exhibit magnetic properties due to the iron content and are widely used in construction and heavy industry because of their inherent strength and durability.
Non-ferrous metals, in contrast, are those that do not contain iron in any significant amount. Examples of non-ferrous metals include aluminum, copper, zinc, and gold. Because they lack iron, non-ferrous metals are generally not magnetic and offer a higher natural resistance to rust and corrosion than their ferrous counterparts. This classification system is based on the bulk composition of the material, not on any thin surface treatments.
The Base Material: Why Steel is Ferrous
The underlying material of galvanized steel is steel, an alloy overwhelmingly composed of iron. Steel is created by combining iron with a small percentage of carbon. Iron remains the dominant element, which means that steel inherently possesses the physical and chemical characteristics of a ferrous metal.
The addition of carbon significantly increases the material’s tensile strength and hardness. Because the iron content remains high, steel retains its magnetism, a hallmark property of ferrous materials. This primary composition—an iron-based alloy—establishes the classification of all steel, including the galvanized variety.
The Role of the Zinc Coating (Galvanization)
Galvanization is a process that involves applying a protective layer of zinc to the surface of steel, most commonly through a method called hot-dip galvanizing. This process involves submerging the fabricated steel item into a bath of molten zinc, which is heated to a temperature of around 860°F (460°C). The zinc metallurgically bonds to the steel surface, forming a dense, corrosion-resistant coating.
Zinc itself is a non-ferrous metal, but its application as a coating does not change the classification of the steel substrate underneath. The zinc layer is purely a surface treatment designed to act as a barrier and a sacrificial anode to protect the iron from rusting. The thickness of this coating is very thin compared to the bulk material, and the fundamental properties of the steel core, such as its strength and ferrous classification, remain entirely unchanged by the superficial layer of zinc.