What Is Galvanized Steel? A Complete Guide

Galvanized steel is widely used in a variety of applications ranging from plumbing to interior and exterior décor. The visually appealing material is corrosion resistant and highly durable. How is it made, and how does it differ from stainless steel?

Galvanized steel refers to steel products that have a layer of zinc metal on their surface. The purpose of the zinc layer is to reduce rust and make the material more resistant under all environmental conditions. Galvanized steel also elongates the lifespan of projects and reduces maintenance costs.

The rest of the article will take a closer look at how galvanized steel is made. You’ll also see the advantages of the material and why you should consider it in your next project.

Galvanizing and Galvanized Steel Explained

Galvanization refers to a manufacturing process where the aim is to coat steel or iron with a layer of zinc to give it more protection and also reduce the chances of rusting. This process can be achieved in different ways, but the most popular is known as hot-dip galvanizing.

Galvanized steel refers to steel products that have undergone the zinc-coating galvanizing process. Once the process is complete, you’ll end up with a product that has the tensile strength of steel and the anti-corrosion properties of the zinc-iron coating.

The zinc acts as a barrier between the metal underneath and corrosive elements in the immediate environment, leading to a better quality steel product and enhanced longevity.

The final product’s versatility is why galvanized steel is used across a wide range of industries ranging from construction to agriculture.

Different Types of Galvanization

As we touched on briefly above, there are different ways to galvanize steel. We will cover them below.

Hot-Dip Galvanization

This is the most popular method of galvanizing steel. Here is what happens during this process:

The steel sheets are dipped into an acidic solution to get rid of dirt.
The sheets are rinsed off properly with the solution after cleaning.
They are passed into an acidic solution designed to get rid of iron oxides (mill scale).
The steel is cleaned again using a chemical cleaning agent such as ammonium chloride and allowed to dry.
Once dry, the sheets are immersed in molten zinc under high temperatures reaching 450°C (840°F).
A bond forms between the zinc on the steel’s surface and the iron molecules on the steel.
As the sheets cool down, they are exposed to air. At this stage, the zinc transforms into zinc oxides (ZnO) due to the interaction with atmospheric oxygen. The zinc also reacts with atmospheric carbon dioxide (CO2). The result is a durable coating of zinc carbonate (ZnCO3), a perfect shield against corrosion.

In hot-dip galvanizing, the type of coating given to the steel can vary from one use case to another. For example, galvanized steel meant for car parts will have a thinner layer than those designed for construction.

Galvannealing

Galvannealing is the product of combining annealing with hot-dipping galvanizing. The result is a special coating on the steel, with a finish that is typically matte gray. Steel galvanized in this manner is used in construction because it is easier to weld, and it makes the material more receptive to painting.

Thermal Diffusion Galvanizing

In thermal diffusion galvanizing, the goal is to have a zinc diffusion coating on the metals. Also known as sherardizing or dry galvanizing, the process does not involve the use of any liquids.During thermal diffusion galvanizing, the metal to be coated is tumbled in a rotating drum containing zinc powder under temperatures of up to 300°C (572 °F). The zinc diffuses into the substrate creating a layer. This type of galvanized steel is used to create small metal products with complex shapes.

Electro-Galvanizing

Electro-galvanizing is another popular method of galvanizing steel. Unlike other methods we’ve seen above, there’s no need to dip the material into a hot tub of zinc. Here, electricity is channeled into a solution of electrolyte containing the steel. This method is carried out within the first stage of steel production.

Pre-Galvanizing

This is another process that is similar to the hot-dip galvanizing method. However, it is performed mostly at the earliest stage of production. The pre-galvanizing process involves rolling the metal sheet under a cleaning agent, making the metal prime for galvanizing.Once clean, the metal is passed through a pool of molten liquid zinc and recoiled immediately. This method’s main benefit is that it ensures the coils of steel are rapidly galvanized on a large scale, delivering a more unified coating than what can be achieved with standard hot-dipped galvanization.

Industries That Use Galvanized Steel

Galvanized steel has been in use for over a century and across numerous environments. This highlights its reliability. Below are some industries where galvanized steel is heavily in use.

Plumbing

Some plumbing companies use galvanized steel in deploying plumbing architecture. Such systems can last for up to ten decades, depending on the region’s prevalent environmental conditions. Galvanized steel can withstand harsher conditions more than some other materials.

Automotive and Aerospace

The bodies of many cars on the roads today are made from galvanized steel. Some decades ago, only the most luxurious car models were built with galvanized metals. Today, the entry-barrier has been lowered considerably. Vehicle manufacturers count on the material’s anti-rust properties a great deal, allowing them to offer buyers warranties.

Aerospace is another industry where all kinds of galvanized materials (including steel) are used to create commercial aircraft parts.

Agriculture

Equipment in the agriculture industry is prone to corrosion. The natural elements and chemicals that come in contact with these materials can wear them down quickly if there’s no protective layer. Galvanized steel means that farmers’ equipment can be more resilient in the face of harsh chemicals and other environmental factors.

Renewable Energy

In the renewable energy industry, consistency is very important as interruptions can lead to significant loss of revenue. This is why the manufacturers in the niche use materials best equipped to handle harsh environmental conditions and fight corrosion.

This is why galvanized steel is one of the materials favored on renewable energy sites. With the corrosion-resistant material, the overall architecture can last for years.

Construction

The construction industry is one of the biggest users of galvanized steel. The material’s durability means that it can be used in residential and commercial projects during the core design stage and for enhancing the project’s aesthetic appeal.

The alluring sheen of galvanized steel brings a contemporary and modern appearance to any structure. This is why the material is popular in fencing, tubing, rails, etc.

Telecoms

The telecoms industry is another one where the major players can’t afford to use inferior materials. Apart from causing disruptions in the overall service, poor materials can also pose a danger to workers around a structure. Galvanized steel provides the durability required for structures in the industry, and the low-maintenance nature of the material is an added incentive.

Advantages of Galvanized Steel

As you’ve partly seen above, galvanized steel holds many benefits. Below is a more general look at the benefits of this material.

It has low initial costs. The initial cost of galvanizing steel is cheaper than other methods of coating steel. The labor-intensive nature of other coating applications such as painting means that many large scale projects choose to go with galvanizing as a first option—except in projects with specific requests.
It requires less maintenance. This means that over the lifetime of a structure built with it, you’re bound to save money. This is why even in applications where galvanizing the steel costs more than other forms of coating, you’ll get more value for money over time. When you also factor in the downtime caused by structures needing regular maintenance, the savings made by going for galvanized steel adds up.
It has a long expectancy. The life expectancy of galvanized steel in various applications can reach more than five decades in favorable conditions. Under severe conditions such as coastal exposure, you can still expect your galvanized steel to last up to three decades.
It is reliable. The best steel companies have to adhere to strict standards during galvanization. They have to stick to a minimum coating thickness, which guarantees you excellent performance in real-life applications. You may also request higher standards, but galvanized steel straight from the factory is still predictable and reliable.
The coating can withstand mechanical damage. With the special metallurgical structure of galvanized steel, it has a coating that can withstand all kinds of mechanical damage during erection, transportation, and maintenance. So, the coating that protects it against the elements also means you don’t have to worry about scratches and dents to the steel in transit.
It protects damaged areas automatically. Galvanization means that corrosion will be preferential to steel. So, when small parts of the steel get exposed due to damage, cathodic protection is triggered automatically. This means there is no need for touch-ups, as is the case with more organic steel coats.
It provides complete protection. All parts of galvanized steel are completely protected. Everything, from inaccessible areas and recesses to sharp corners, is covered adequately. You won’t get this level of protection if you apply the coating to a steel structure that has already been completed.
Inspection is easy. A big advantage of galvanized steel is that you can assess the coating with your eyes only. The galvanization process is such that you can tell if coatings look sound and continuous by just looking at the material. You can also quickly measure the thickness of the coating with methods that are non-destructive and simple.
The erection time is faster. Galvanized steel comes ready to use from the factory. You don’t have to spend additional time on-site inspecting, painting, or preparing the pieces for use. Similarly, you won’t lose any time once the structure is completed. You can move to the next stage of construction (or start using the structure) immediately without any additional special processes.

The Difference Between Galvanized Steel and Stainless Steel

Stainless steel and galvanized steel have a very similar look, which means that they can be mistaken. However, they are different. Below is a look at the differences between the two of them.

The Preparation Process

As we’ve seen above, galvanized steel is mostly made by dipping steel into a tub filled with molten zinc. It can also be made by other methods of galvanization, but hot-dipping—as the process is called—is more popular.

With stainless steel, the steel is mixed with chromium. The mixing process is carried out when both materials are in their molten state, and the ratio will come down to what type of stainless steel is needed for a project. When the mixture is cool, it will harden into a solid-state. Impurities are treated with acid to give a clean sheen.

The Structural Composition

Galvanized steel only contains regular steel but is coated by zinc, while stainless steel is two separate metals mixed thoroughly. Therefore, both types of steel are structurally different. While galvanized steel is pure steel but coated, stainless steel will contain at least 10% chromium.

Strength, Pricing, and Usage

Both types of steel are very strong, but the mixture of chromium means that stainless steel is stronger than galvanized steel. Stainless steel is also costlier than standard galvanized steel. This is why the latter is used in large scale projects where stainless steel is impractical and won’t fit into the budget. However, for heavy-duty projects with a big budget, stainless steel is often preferred.

Top Galvanized Steel Companies in the US Today

Below is a look at some of the top providers of galvanized steel in the US today.

Bloomsburg Metal Company LLC

This company is a distributor of steel products based in Wilkes Barre, PA. Apart from providing a wide range of steel products for use in construction or as raw material, the brand also provides custom galvanized steel amongst other types of fabrication. This makes the brand a leading name in the sector.

Plateco Inc.

The brand provides zinc plating for different infrastructure applications. They offer three main methods of galvanization, and they have a fast turnaround time on projects—typically within four days. Based in Reedsburg, WI, the brand has a team of highly skilled technicians and automation, which allows them to produce high-quality steel trusted around the country.

All-Service Metal Treating Co.

This is another company certified to deliver galvanizing and plating services. They are based in Trenton, NJ. You can count on them for services such as conversion coatings, dying, mechanical galvanizing, and more.

Do you want another coating material for your steel instead of zinc? All-Service Metal Treating Co. can also work with copper, tin, and cadmium to deliver the result you want, exceeding industry standards where necessary.

Los Angeles Galvanizing Co.

Based in Huntington Park, CA, this brand specializes in providing hot-dip galvanizing service across the Western US. You can count on them for galvanizing and other services such as ASTM-certified degreasing, pickling, fluxing, and other similar steel-related services.

Frontier Hot-Dip Galvanizing

This hot-dip galvanizing company provides its services to Buffalo, NY and nearby areas. Their clientele covers the transportation, manufacturing, public utility, and commercial construction sectors. All galvanized steel parts are tested before and after dipping within their in-house lab.

With a tank capacity that allows progressive dip coatings for materials that are up to 40 feet (12 meters) in length, you can trust the brand for heavy-duty solutions.

Korns Galvanizing Co.

Based in Johnstown, PA, this company delivers quality hot-dip galvanizing for castings, stampings, forgings, fasteners, fabricated parts, and more. The company emphasizes proper documentation to ensure they leave all customers satisfied at the end of a project. The brand is a member of the American Galvanizers Association (AGA). They are also ISO certified.

East Coast Welding

This is a custom manufacturer of steel products based in Gilford, NH. Among their other services, they provide galvanizing, plating, powder coating, and painting for all steel parts. You can count on them to prototype or finish your products. The brand has been around for nearly three decades, serving the residential, marine, commercial, and electronic industries effectively.

DynaBurr Chicago

This company’s plating capacity goes over 140 cubic feet (3.96 cubic meters). They work in line with the standards set by the National Association for Surface Finishing (NASF) and the American Society for Testing and Materials (ASTM). They are based in Northlake, IL, offering their services to businesses in the construction, automotive, and industrial sectors.

MST Steel Corp.

This brand focuses mostly on servicing the automotive industry. They have worked with some of the most popular names in the industry, including Ford, Tesla, GE, and Volkswagen. They have tons of lab-tested galvanized steel, ready to ship across the US, Mexico, and Canada.

Commercial Electro Plating Inc.

With headquarters in Fresno, CA, this is a galvanizing company you can count on to work on steel parts weighing up to 10,000 lbs (4500 kg). The company also offers tin and nickel plating, offering a quick turnaround time on all services. They aim to complete all orders within three days.

Choosing a Galvanized Steel Company to Work With

We’ve looked at some of the popular galvanized steel companies above. How do you choose the right one to work with? Here are some tips to guide you:

Size and Quality of the Workforce

When evaluating any company’s workforce, the first thing you need to do is find out how many people they have got on the payroll. The raw numbers are a good pointer on whether they have the staff strength to meet your deadlines but do not forget to factor in variables like the depth of automation.A company with 50 workers and lots of automated processes may deliver faster than one with 100 workers where everything is done manually.

Away from the numbers, you need to ensure the staff has the right skills you’re looking for. If you want custom galvanization for your steel parts, you need to be sure they can meet specifications. Again, the best way to ascertain the skill level is to pay attention to the type of projects they have worked on in the past.

Reach of the Portfolio

This is the company’s experience level, but it goes beyond just checking the company’s age. Do they have experience working on steel projects in your industry? Do they have experienced staff that can understand the intricacies of your project? If the brand does not tick these boxes, there is a high chance that they might deliver results that do not meet your needs.

For example, a business with experience working in architecture-related projects may not provide satisfactory results to your brand if you are in the automotive niche. So, you need to ensure the company has the technical skills to handle the scale of the project and has also worked for several clients in your industry in the past.

Competitive Pricing

The steel fabrication process will gulp a sizable portion of the budget set aside for any project. You need to ensure that the company you choose to go with for your galvanized steel can meet your demands while also offering competitive pricing. At this stage, you may have quotes from multiple companies on your desk. Going with the cheapest quote may not equate to competitive pricing.

Companies using lower-quality raw materials and older tools to produce your galvanized steel will most likely charge lower than average fees. Others that use higher quality material and cutting-edge technology may charge higher fees but are most likely to meet your standards and complete the job on schedule—saving you time and money that will be wasted on delays and remakes.

The location and overall size of the company will also influence how much they charge on your project. Therefore, you need to take a holistic approach when analyzing the quotes received for your project. Provide the companies with a minimum requirement and work with quotes that have taken those requirements into account. Watch out for extra costs and possible hidden charges.

Adherence to Standards

You should focus on working with companies that will hit the standards you want on your project. The best ones deliver excellent results on both big and small projects. Apart from meeting standards set by regulatory bodies, the company’s work should pass your business’s unique tests.

Discuss with the company to ensure they understand the manufacturing processes you want and ensure they have the equipment to test compliance.

Overall Customer Service

You need to choose a company that knows how to manage relationships with clients of all sizes. It may be difficult to see a brand’s customer service skills from outside, but you can get an idea from your initial communications with them. How quickly do they respond to inquiries through their designated contact channels? Do they sound professional in correspondence?

You can also speak with some of their past customers to see what they think about them. The best companies have a list of clients they have worked with on their websites. Where not listed, they should be willing to share this information with you.

The Brand’s Resource Level and Financial Standing

The best steel fabrication companies tend to have cutting-edge metal designing and manufacturing equipment. They have the resources to handle every aspect of the project from scratch, covering everything from design to final delivery to you. Such companies also typically have lots of automated processes, which help them avoid quality control errors.They also won’t shy away from installing new technology where necessary for custom projects. You need to ensure your chosen metal fabrication company is financially stable—enough to spend more money where necessary, hire new technicians to increase production capacity, etc.

A financially sound company will also have a motivated workforce and won’t have unhappy suppliers on their books. If the brand’s suppliers are happy, you can be sure that they will use the best raw material possible, and your project won’t get delayed.

Conclusion

Galvanized steel is one of the pillars of many industries today. The galvanization process is carried out by highly-equipped companies with the resources needed to produce finished steel that meets regulatory standards and can meet the specific project demands.