What Is Galvanizing? The Use and Benefits of Galvanized Metal

Steel and iron have a wide range of use and they play an important part in construction. You’ve probably noticed that your gates, balconies, fences, car parts, and home appliances are mostly made of metal. Now, the one downside to this material is that it’s prone to rusting.

There probably isn’t a living soul in this world that actually likes the sight of the reddish-brown spots. But that doesn’t change the fact that, without proper protection, rain, humidity, and harsh weather would easily damage the metal. Galvanizing is one of the most efficient methods of protecting iron and steel from this nuisance.

By choosing to galvanize metal, you are choosing a simple, reliable, and cost-effective way to increase the lifespan of your products or property.

What Is Galvanizing?

Galvanizing is applying a thin layer of zinc to a base metal (usually iron and steel) in order to help shield it from the environment. This process further prevents premature corrosion and rust formation.

Rust is actually an iron oxide, and it is formed by iron and oxygen in the presence of moisture from water or air. Depending on the climate and the environment, iron and steel can rust incredibly quickly, while the process is somewhat slower with zinc.

The thin, silver zinc layer protects the thick base metal from the elements, securing a long life and simple maintenance. As opposed to plastic coating protection or painting that often chips, flakes and falls off, galvanizing offers toughness and additional strength.

How Does Galvanizing Work?

Galvanizing is a natural metallurgical reaction and it doesn’t require any manual labor. Because it’s a natural reaction of clean steel to the zinc plating, the bond becomes a part of the steel, unlike some other forms of protection such as painting. Moreover, galvanizing is a process that can be repeated over and over again, but it guarantees protection from day one.

The process itself helps shield the base metal in different ways:

  • Firstly, it creates a thin zinc coating of the base metal, protecting it from environmental influence. The zinc prevents moisture from the air and other elements from damaging and corroding the base underneath.
  • Secondly, galvanization helps protect the base metal through “galvanic corrosion,” an electrochemical process that occurs when two metals with different corroding potentials make contact. With the help of an electrolyte, one metal acts as a cathode and the other one as an anode. The anode corrodes rapidly, protecting the cathode. During the galvanizing process, zinc tends to act as the anode when it comes in contact with many different metals. That slows the corrosion of the base metal or the cathode.

The cathodic protection zinc offers shields even the exposed, small areas with minor surface damage. As long as the zinc coating is present, those spots won’t be needing a touch-up any time soon.

The Benefits of Galvanizing

You can find galvanized steel and iron wherever there is an even remote potential for rusting. Many different industries use them because they offer an array of benefits, for both residential and commercial environments.

Galvanized Metal Has Significantly Longer Lifespan

The galvanized coating is one of the most effective types of steel protection available. The average lifespan of a piece of galvanized steel is well beyond 50 years in rural areas and average urban environments. Using galvanized metals as construction material leaves you feeling confident for many years to come.

Galvanizing Offers Great Value for Money

The cost of applying a galvanized coating is lower than that of other steel treatments and coating alternatives. The application process is simple and fast, and the final product is ready to use immediately.

On the other hand, some alternatives, such as specialized painting are much more labor-intensive, which results in a higher cost for the contractors.

Galvanizing Is a Reliable, Standardized Process

Galvanizing is a fast, relatively simple process. A controlled environment of the galvanizing plant means there are no surprises. There are clear standards for the thicknesses of coating and they are very specific. Even the minimum coating thickness improves the performance and strength of the base.

Also, this metallurgical bond is much stronger than any chemical or mechanical bond. The zinc layer becomes a part of the base metal, making it incredibly resistant to damage.

Galvanized Metal Is Ready and Easy to Use

You can use and assemble galvanized metal parts immediately. There’s no need for an additional touch up, painting or coating. Right after the delivery, the parts are ready for the next stage, thus accelerating your construction work greatly.

Galvanizing Is Environmentally Friendly and Sustainable

Both zinc and steel are natural materials that are easily recyclable. Galvanizing is relatively safe and the environmental burden is relatively low. The process itself is energy efficient and the final product has a long life expectancy. Such materials require low maintenance, too.

Different Galvanizing Methods

There are various different galvanizing processes available, some more popular than others.

Hot-Dip Galvanizing

Hot-dip galvanizing is the most common and the most popular method of galvanizing metals. As the name implies, this process involves dipping the base metal into a pool of  melted zinc maintaining the temperatures higher than 800°F.

The first step is cleaning the base metal either mechanically or chemically. After cleaning, fluxing removes any remaining oxides from the metal.

Last and the most relevant step is dipping the base into heated zinc to form the metallurgical bond. Removing the metal from the hot bath leads to its reaction with oxygen in the aerosphere and the creation of zinc oxide. In reaction to carbon dioxide, zinc oxide further creates the final layer of protection, zinc carbonate.

The distinctive pattern resembling crystals develops on the surface of the metal and is a sure sign of hot-dip galvanizing.

Pre-Galvanizing

Pre-Galvanizing is performed at the first stage of production and it’s very similar to hot-dip galvanizing. Most often it’s the first step, in the steel mill, for materials that already have a certain shape or are coiled immediately after galvanizing.

This method involves bathing the metal in a cleaning compound in order to prepare it for dipping into the heated pool of zinc. Once the metal passes through the molten zinc, it is coiled immediately.

The main advantage of pre-galvanizing is that it provides quick galvanization of steel sheets. Also, large scale galvanization is possible and it provides a more uniformed coating than hot-dipping.

The main drawback of this process is that it leaves unprotected spots. Cutting a long metal sheet into smaller pieces for further production leaves exposed and unprotected edges that are prone to corrosion.

Galvannealing

Galvannealing is a combination of the annealing process and hot-dip galvanizing. Annealing is heating of metal at a specific temperature with the intention to improve ductility and reduce brittleness.

Combining these two processes results in a very specific coating on base metals (mostly steel). Galvannealed steel, for example, is first dipped in zinc and then warmed to provoke alloying between the steel and the zinc layer. The final outcome is a matt surface ideal for painting and welding.

Electrogalvanizing

The only method that doesn’t involve dipping metals in a molten bath of zinc is electrogalvanizing. Instead, the process uses electric current in an electrolyte solution to transfer zinc ions onto the metal.

The electric current reduces positively charged zinc ions to zinc metal, which then transfers onto steel, forming the coating. Similarly to pre-galvanizing, electrogalvanizing is mostly used in the first phase of production.

This method offers a uniform coating of an exact thickness. However, the layer is usually thinner, providing less protection to the base.

Galvanized Metal Is Everywhere for a Reason

Galvanized metal is a popular choice in telecommunications, automotive industry, wind and solar industries, as well as construction. Regardless of your line of work or lifestyle, you’ll find galvanized metal all around your business venues as well as your household. Galvanizing is an affordable, reliable way to increase the lifespan of a final product. Moreover, it looks incredibly attractive while preventing corrosion from developing. Choose the method which best suits your needs and talk to your contractor to ensure long lasting protection of your metal.

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