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What is Galvanized Steel?

Meaning of Galvanized Steel

Galvanized steel is steel that has gone through a chemical process to prevent it from corroding. Steel is coated in layers of zinc oxide because this protective metal does not rust as easily.

The coating also gives the steel a more durable, scratch-resistant finish that many people find attractive. For countless outdoor, marine, or industrial applications, galvanized steel is an essential manufacturing component.

how it’s done

One of the most common ways to make steel resist rust is by combining (alloying) it with a metal that is less likely to corrode: zinc. When steel is immersed in molten zinc, a chemical reaction permanently bonds the zinc to the steel.

So zinc isn’t exactly a sealant, like paint, because it doesn’t just cover the other metal; it actually becomes permanently a part of him. The outermost layer is all zinc, but successive layers are a mixture of zinc and iron, with an interior of pure steel.

This process, known as hot-dip galvanizing, is one of the most common methods of making galvanized steel, but it’s not the only one.

Continuous sheet galvanizing passes a steel sheet or wire through molten zinc; It is also a form of hot dipping, but it leaves a thinner layer of the protective metal.

Steel can also be painted or zinc sprayed, although neither method creates the strong bond that hot dipping does. Electrogalvanizing or electroplating uses electricity to create the bond between the two metals, resulting in a relatively thin layer of zinc.

The steel cable can be galvanized to protect it from rust and corrosion.

The degree of galvanization is usually described as the weight of the zinc per surface area rather than its thickness, because this provides a better representation of the amount of metal that has been applied.

Steel is often galvanized after individual parts, such as braces, nails, screws, beams, or bolts, have been formed. However, continuous sheet galvanizing is often done before the metal is used to create products, and it can withstand some bending and forming without flaking.

Galvanized steel can be made into sheets for a variety of applications.

Benefits of galvanizing

Zinc protects steel in two ways. First, it is highly resistant to rust; Iron, a major component of steel, reacts very easily with oxygen and moisture and will eventually disintegrate.

The zinc layer on the surface prevents those elements from reaching the steel as quickly. It also develops a patina, a layer of zinc oxides, salts, and other compounds, which offers further protection.

Zinc is also extremely durable and scratch resistant, and has a satin-like appearance that many find attractive.

The outer layer also protects the steel by acting as a “sacrificial layer”. If, for some reason, rust adheres to the surface of the galvanized steel, the zinc will corrode first.

Even in areas where the surface is scratched or damaged, the surrounding zinc still corrodes before the steel. The service life of galvanized steel varies, but industrial steel with a 3.9 mil (0.0039 inch or 0.09906 mm) coating thickness can last more than 70 years without maintenance under average conditions.

Uses of Galvanized Steel

Galvanized steel can be found almost everywhere. Many people live in steel frame homes, and the buildings are often made with galvanized steel roofs.

There are multiple pieces of steel in cars that help protect them from the weather, and it is used in many marine applications due to its ability to resist salt and the elements. In addition to being inexpensive, durable, and effective, this metal is also popular because it can be recycled and reused multiple times.

Disadvantages

Galvanizing has relatively few disadvantages, but it is not a good method of protecting all steel items. Some items cannot be hot dipped, often because they are too large or too small, and other forms of galvanizing are often not as protective and durable.

Eventually the zinc will corrode, although how long it takes depends on the thickness of the coating and the environment. Galvanized steel has a much shorter lifespan when regularly exposed to rain or seawater.

Galvanized steel that cools too slowly or is stacked before they have completely cooled can also cause the outer layer of zinc to peel off.

In some cases, small spaces can form between the zinc and the underlying alloy, which can also cause flaking. When a very thick layer of zinc is applied, it can also become brittle and flake off.

Alternatives to Galvanization

Some metal items cannot be galvanized effectively; The zinc coating would be too thick on a small screw, for example. In many cases, stainless steel, made with chrome, is used. Unlike galvanized metals, stainless steel is not coated on the metal; Chromium is part of the composition of the steel alloy.

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