What is Galvanized Steel Coil and Why Do We Use Them?

Galvanized Steel: Exploring Types, Uses, and Benefits

Welcome to the Worthington Steel blog! In this article, we will delve into the world of galvanized steel. Whether you're new to the industry or a seasoned professional, understanding galvanized steel's different types, uses, and benefits is essential.

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First, we'll provide a comprehensive overview of galvanized steel, explaining its unique properties and how it is manufactured. Next, we'll explore the wide range of applications where galvanized steel excels, from construction and automotive to agriculture and beyond.

One of the main reasons galvanized steel is so popular is its numerous advantages. We'll discuss these benefits, including its exceptional corrosion resistance, durability, and cost-effectiveness. Additionally, we'll provide insights into the considerations and maintenance required to keep galvanized steel in optimal condition.

Finally, as a leading provider of high-quality flat-rolled steel products, we'll highlight why choosing galvanized steel from Worthington Steel could benefit you. Our commitment to excellence as a solutions provider sets us apart from the competition.

What is Galvanized Steel?

Galvanized steel is a type of steel that has been coated with a metallic layer to protect the base steel substrate from corrosion. Types of galvanized coatings include zinc (Zn), aluminum (Al), combinations of zinc & aluminum, and combinations of zinc & aluminum & magnesium.  These metal coatings can be added electrolytically or through the hot dip galvanizing.  The hot dip galvanizing process can be performed through brief immersion in a molten metal bath (batch process) or more efficiently through a continuous process where steel passes through a molten metal pot.  These metals offer galvanic protection to the steel substrate, sacrificially corroding themselves before the underlying steel substrate due to the higher electrochemical potential of the metal layers.  This process provides a durable, long-lasting finish, making galvanized steel highly popular in various steel-intensive industries.

Where is Galvanized Steel Used?

Galvanized steel is widely used in various industries for its exceptional properties and durability. Let's explore some of the key applications of galvanized steel:

Galvanized steel in construction and infrastructure:

Galvanized steel is extensively used in the construction industry for its corrosion resistance and strength. It is commonly used for roofing, wall panels, framing, and structural components. The coating protects the steel from rusting, increasing its lifespan and reducing maintenance costs.

Galvanized steel in automotive manufacturing

Galvanized steel is vital in the automotive industry, where safety and durability are paramount. It produces car bodies, chassis, and various structural components. The galvanized coating provides excellent protection against corrosion, ensuring the longevity of vehicles even in harsh environments.

Galvanized steel in electrical and telecommunications

Galvanized steel is widely used in electrical and telecommunications infrastructure. It is used for cable trays, poles, towers, utility boxes, cabinets, enclosures, outlet boxes, lighting equipment, and conduits. The galvanized coating provides excellent corrosion resistance, making it suitable for outdoor installations and ensuring the reliability of these critical systems.  

Galvanized steel in agriculture

Galvanized steel is utilized in several applications in the agricultural industry.  It protects high-tech center-point irrigation systems as they irrigate crops in the fields. It is also widely utilized to manufacture shiny grain bins that withstand all weather environments. 

Galvanized Steel in Solar Energy

Galvanized steel is an important material in the manufacture of solar racking and solar ground mounts, protecting them from weather conditions.

Worthington Steel offers many galvanized steel products that meet the highest quality standards. Our galvanized steel is known for its exceptional performance, reliability, and long-lasting protection. Whether you require galvanized steel for construction, automotive, or electrical applications, we have the right solutions to meet your needs. Please reach out to us today to learn more about our galvanized steel products and how they can benefit your projects.

What is Hot-Dipped Galvanized Steel?

Worthington Steel produces a type of galvanized steel known as hot-dipped galvanized steel. When producing hot-dipped galvanized steel, the steel is first cleaned to remove any surface impurities and then dipped into a bath of molten zinc. The zinc coating bonds with the steel by developing an intermetallic layer, which forms a protective layer that acts as a sacrificial barrier against moisture, chemicals, and other environmental factors that can cause steel corrosion.  The zinc coating sits on top of steel and isn’t chemically bonded, making it more prone to chips. Galvanized coating is best for non-surface critical applications requiring high corrosion resistance, such as culverts, grain bins, and guard rails. 

What Other Types of Hot-Dipped Coatings Does Worthington Offer?

Galvanneal

A galvanneal coating is produced by annealing galvanized steel. During the annealing process, the zinc bonds to the iron in the steel, producing a zinc-iron alloy. The galvanneal coating is smoother and harder than the galvanized coating, making it superior for exposed painted applications and more resistant to surface damage.   Galvanneal is often selected for car bodies.

Aluminized (type I,II)

"Aluminized Type 1" steel refers to steel coated with a layer of aluminum-silicon alloy through a hot-dipping process. This coating provides several benefits to the steel, including enhanced corrosion resistance, improved heat resistance, and increased reflectivity.  This protective barrier is beneficial in environments where exposure to moisture, chemicals, or high temperatures is a concern. Typical applications are heat exchangers and automotive exhaust systems.

"Aluminized Type 2" steel also utilizes an aluminum-silicon alloy, but there are differences in the coating processes and properties.  This type of coating is best for applications where extremely high-temperature environments and corrosion are significant concerns.  Aluminized Type 2 offers superior corrosion protection to aluminized Type 1.  Applications for type 2 would be heavy-duty industrial equipment exposed to harsh conditions and applications involving chemical processing where heat and chemical exposure are factors.

Galvalume

Galvalume is a coating made of zinc and aluminum. The name “galvalume” is a combination of “galvanized” and “aluminum – the two main components of the coating.  Before the steel is dipped into the zinc bath, it is coated with a thin aluminum-silicon alloy layer.  This aluminum-silicon coating provides several advantages over traditional galvanized coating: enhanced corrosion resistance, improved heat resistance, better formability, and a longer lifespan.  The heat tolerance and formability make this coating ideal for metal roofing and siding in hot climates.

Advantages of Galvanized Steel

Galvanized steel offers several advantages, making it a popular choice in various industries. Let's explore some of the key benefits:

Enhanced Corrosion Resistance

One of the primary advantages of galvanized steel is its exceptional protection of base steel substrate. The galvanization process involves applying a protective zinc coating to the steel surface, which forms a barrier against moisture, chemicals, and other corrosive elements. This zinc coating acts as a sacrificial layer, protecting the underlying steel from rust and corrosion. As a result, galvanized steel exhibits superior resistance to environmental factors, making it ideal for outdoor applications.

Longevity and Durability

Galvanized steel is known for its long-lasting durability. The protective zinc coating provides an additional layer of defense against wear and tear, extending the steel's lifespan. This makes galvanized steel a cost-effective choice in the long run, as it requires minimal maintenance and replacement. Whether used in construction projects, automotive manufacturing, or infrastructure development, galvanized steel stands the test of time.

Cost-effectiveness in the Long Run

While the upfront cost of galvanized steel may be slightly higher than that of other materials, its long-term cost-effectiveness must be considered. Galvanized steel's enhanced corrosion resistance and durability reduce the need for frequent repairs, replacements, and maintenance. Additionally, its resistance to rust and corrosion eliminates the need for protective coatings or sealants, further reducing costs. Its longevity and low maintenance requirements make it an economical choice for various applications. It also acts as a natural lubricant in roll-forming operations.

Considerations and Maintenance

Regarding galvanized steel, proper handling, and storage are crucial to maintaining its quality and effectiveness. Here are some guidelines to follow:

Handling

Handle with care: Galvanized steel is coated with a protective layer of zinc, which can be scratched or damaged if mishandled. Avoid dropping, dragging, or sliding galvanized steel to prevent any potential damage to the coating.

Storage

Store in a dry, well-ventilated environment. Moisture can accelerate corrosion on galvanized steel, resulting in white rust caused by zinc oxidization. Before fabricating, storing galvanized steel in a dry environment is essential to minimize exposure to moisture or humidity. Regardless, a well-ventilated storage area with low humidity levels is ideal for long-term storage—ceiling fans are an excellent solution to prevent white rust from occurring.

Choosing Galvanized Steel from Worthington Steel

Worthington Steel offers a wide range of galvanized steel products designed to meet our customers' diverse needs. Whether you are in construction, automotive, or any other industry that requires durable and corrosion-resistant materials, our galvanized steel is the perfect choice.

Our galvanized steel products are available as master coil, slit, or cut-to-length sheets, and our customers fabricate, stamp, roll form, or bend. We understand that different projects have different requirements, which is why we offer customization options to ensure that our galvanized steel meets your exact specifications and can offer you galvanized, galvanneal, and type I or type II aluminized (used for heat-resistant applications or culvert, respectively).

When it comes to quality, Worthington Steel is committed to delivering nothing but the best. Our galvanized steel undergoes a rigorous process to ensure its strength, durability, and corrosion resistance. We adhere to strict quality standards and continuously invest in advanced technology and innovation to provide our customers with the highest quality products with the consistency you demand.

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 The steps in the galvanizing process are as follows:

• The steel is cleaned in a degreasing solution
• After being cleaned, the steel is pickled by being lowered into a vat of diluted hot sulfuric acid
• The steel is then fluxed in an aqueous solution (typically zinc-ammonium chloride)
• After the flux, the steel is galvanized through immersion in a vat of molten zinc
• Afterward, the steel is inspected for consistency and a complete coating

What are the advantages of galvanized steel?

Many different industries utilize galvanized steel primarily because it has such a wide array of benefits for industries to take advantage of, including having:

Low initial cost compared to most treated steels. In addition, galvanized steel is immediately ready to use when delivered. It does not require additional preparation of the surface, inspections, painting/coatings, etc. sparing companies more costs on their end.

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. There is no maintenance required. The increased durability of the steel’s finished product also increases the product’s reliability.

The sacrificial anode 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. The coating will corrode preferentially to the steel, creating a sacrificial protection to the areas that are damaged.

Rust resistance from the zinc coating. The iron elements in steel are incredibly prone to rusting, but the addition of zinc acts as a protective buffer between the steel and any moisture or oxygen. Galvanized steel is very protective, including sharp corners and recesses that couldn’t be protected with other coatings, making it resistant to damage.

Different methods of galvanizing

As stated above, there are several different processes for galvanizing steel.

Hot-Dip Galvanizing

The first and foremost method for galvanization is hot-dip galvanizing. The process is very similar to what the name suggests! In this method, steel or iron is dipped in a molten pool of zinc that maintains a temperature of around 860°F (460 °C). This molten bath begins a metallurgical bond between the zinc and the receiving metal. After the metal is pulled from the bath, it reacts to being exposed to the atmosphere, and the pure zinc mixes with oxygen to form zinc oxide. The zinc-oxide further reacts to carbon dioxide and forms zinc carbonate, which makes up the final protective coating on the material. The tell-tale sign of a hot-dipped galvanized material is the presence of a crystalline-like pattern on the surface, sometimes referred to as “spangle.”

The hot-dipped galvanizing method is an economical choice that can be quickly executed on both simple and complex shapes. 

The new coated material can be worked and machined in a similar fashion to uncoated materials. Galvanized steel can be used in high-temperature applications up to 392 °F, but use in temperatures exceeding that level will cause the zinc-carbonate layer to peel off. 

Galvannealing

Galvannealing is the outcome of combining the annealing and hot-dip galvanizing processes in order to produce a specialized coating on steel. The process of galvanization is performed via hot-dipping and instantaneous annealing, which produces a matte gray finish.

Galvannealed steel is a zinc-iron alloy product, where the base metal is coated by the hot-dip process, then heated to induce alloying between the molten zinc coating and the steel. The resulting finish is a dull matte surface. Galvannealed steel is conducive to welding and the surface is excellent for paint adhesion.

Pre-galvanizing

Also similar to the hot-dip galvanizing method, but performed at the very first stage of production. Pre-galvanizing is a process that involves rolling the sheet metal through a cleaning agent to quickly prime material for galvanizing. Then, the metal is passed through a pool of molten liquid zinc and is immediately recoiled. The primary advantage of this method is that coils of steel sheet can be rapidly galvanized on a large scale with a more unified coating than the traditional hot-dipped method.

Electrogalvanizing

The most unique of these outlined methods, electrogalvanizing does not involve dipping the material in a molten vat of zinc. Instead, an electric current is introduced to an electrolyte solution that is applied to the steel, which reduces positively charged zinc ions to zinc metal – which is then deposited on the positively charged steel. Like pre-galvanizing, this method is typically done at the first stage of production.

Galvanizing advanced high-strength steel

For more information about the galvanization process for advanced high-strength steel, as well as our partner National Galvanizing, please click here.

What industries utilize galvanized steel?

Galvanized metals are used everywhere!

The bodies of cars and many bicycles are made from galvanized metals. Some drinking water pipes are still made from galvanized steel. Cool rolled sheet metal is also frequently galvanized. Nuts, bolts, tools, and wires of all kinds are now galvanized because it is a cheap process, and helps boost the metal’s lifespan!

Galvanized steel, in particular, is often what is used in modern “steel frame” buildings. Galvanized steel is also used to create structures like balconies, verandahs, staircases, ladders, walkways, and more. Galvanized metal is the ideal choice if your project will live outside after it’s done. Fences, roofs, outdoor walkways, these are all great choices for galvanized metal!

• Wind & solar industries – Solar projects must have a continuous workflow once installed and any repairs/maintenance results in disruption to service (a.k.a. revenue loss). This means that hot-dipped galvanized steels are popular in solar projects for their corrosion protection. It is also popular for its ‘environmental’ friendliness because it does not produce emissions and ensures decades without maintenance. For example, it is often utilized in the agriculture industry because the equipment is susceptible to being easily corroded, creating a demand for tougher, more resilient equipment. Hot-dip galvanized steel provides corrosion protection that can often last for decades, even when exposed to the harsh environment of farming.

• Automotive industry – Though only used on luxury models up until the s, the use of zinc-coated bodies for automobiles is now the norm in auto manufacturing. The ‘body-in-white’ of a car makes up about 80% of the body, all using galvanized steel. The rust -resistance of galvanized steel is also a good marketing tool for the automotive industry because it can provide ‘anti-rust warranties’ to customers.
• Construction industry – Whether for residential or commercial, the durability of galvanized steel has made it popular for over a century in the construction industry. It is also selected for construction because of its aesthetics; The ‘shine’ that galvanized steel provides gives it a contemporary feel and is popular in modern architectural designs. Also, it isn’t just used for large structural pieces but things like fencing, gutters, rails, tubing, poles, and much more.
• Telecommunication industry – lines are not an easy maintenance job, they are tall and often difficult to reach. Hot-galvanized steel can be used on wiring and equipment boxes which decreases the risk of damage and need for maintenance at all.

Well, there you have it! With our partner Heidtman Steel, National Galvanizing  runs a 245,000-square-foot facility, featuring pickling, galvanizing, galvannealing, and slitting, all in one location, convenient to major markets. This combination of capabilities provides our customers with unparalleled responsiveness to meet the ever-changing demands of today’s market.

For more information, please visit Galvanized Steel Coil(in,vi,ar).