Can Visual Defects of Galvanized Steel Affect Its Strength?

From bumps and pinholes to flaking and scratches, defects of galvanized steel can appear in a few different ways. It is important to understand that some of these defects are only visual, while others can be a sign of poor quality galvanizing.

If your galvanized steel has noticeable visual defects, it is smart to verify its quality is uncompromised before using it in your build. If you want to order galvanized materials with confidence every time, working with a reputable company is the best option.

At South Atlantic, we are galvanized steel experts. With decades of experience galvanizing our own materials and working with steel manufacturers across the country, we take great pride in giving our customers the best building materials, every time. 

You can learn more about our Galvanized Steel division, or you can keep reading to understand more about defects in galvanized steel and what they could mean for your project.

What Are The Most Common Galvanized Steel Defects?

Galvanized steel is famous for its corrosion-resistant zinc coating. 

This coating’s impressive resilience isn’t the only thing that makes it popular. It is also an aesthetically pleasing, durable material. It is often a shiny, silvery-gray color. It is smooth and sleek, making it a popular choice for stadium handrails and monuments. 

While defects in galvanized steel are not necessarily a common issue, there are some imperfections that are more likely to appear than others. These include:

• Small bumps under the coating
• Pinholes in the coating
• Surface-level scratches 

The first two are the result of poor galvanizing, while the scratches can be the result of poor handling during shipment.

Some less common visual defects of galvanized steel include:

• Marks left behind by the chains or wires used during the galvanizing process
• Distortion of thin galvanized steel or galvanized wire mesh, which results in it looking wavy or buckled
• Drainage spikes, which look almost like icicles of zinc hanging off the sides of the galvanized piece

Some of these imperfections can look more concerning than they are. Understanding what caused them will help you know if the quality of the galvanized steel is trustworthy. 

What Causes Defects During the Galvanizing Process? 3 Main Possibilities

Most causes for visual imperfections in galvanized steel generally fall under three categories. They are: 

• Poor preparation before galvanizing
• Incorrect galvanizing
• Clumsy transportation

1. Poor Preparation of Steel Causes Bumps and Holes

How well a manufacturer prepares its steel for galvanizing will have a huge impact on the resulting coating. This goes for both the coating’s final appearance and quality. 

Preparing steel for galvanizing means thoroughly cleaning it to ensure the zinc adheres to the entire surface. But, when dirt, dust, oil, or even old paint are still stuck on the steel before it is immersed in the zinc, those dirty areas often become visual defects. 

For example, a small bit of dirt that was on the steel before galvanizing may fall off afterwards, leaving behind a pinhole. Or, paint under the surface that was not removed beforehand can start to chip or peel, causing the coating to begin flaking or peeling, also.

2. Incorrect Galvanizing Leaves Areas Uncovered

In order for the entire steel piece to receive the zinc coating during galvanizing, it must be fully immersed in the molten zinc bath. When this doesn’t happen, sections may not receive the coating. How large those uncovered sections are will determine the quality of the final galvanized materials. 

This is when defects like chain marks we mentioned earlier can occur. If the chains used to lift and lower the steel into the zinc are too tight or not shifted around during the process, the steel underneath them can remain uncoated. 

Another common reason for spots to still be bare after galvanizing is when the piece of steel is too large to fit in the zinc bath. To galvanize large pieces, they have to be strategically dipped from different angles to make sure the entire surface area is coated. It can be easy for small, overlapping areas to be missed in this process.

Rough handling during the galvanizing process can also lead to scratches or damage to the zinc coating. This can include moving the steel pieces too closely together or rushing the cooling process, leading to abrasions or a soft coating.

3. Poor Transportation Practices Scratch the Zinc Coating

Care is still necessary when transporting galvanized steel. Improper loading, tight stacking, or inadequate padding during transit can cause the surfaces to rub against each other. This can cause scratches or chips in the coating. Rough or careless unloading at the destination can also harm the protective layer.

Galvanized steel’s zinc coating does have self-healing properties, but it is not able to seal up scratches that reach a certain point. And that is where understanding the difference between visual and structural defects becomes important.

Can Visual Defects Impact the Strength of My Galvanized Steel Materials?

As the American Galvanizers Association (AGA) explains, there may be different opinions about how perfect the final appearance of galvanized steel needs to be. 

So, the two factors that decide whether a visual defect impacts the steel’s quality are the “effect on corrosion resistance and intended use.”

• The first of these two factors is self-explanatory. If the defect will hurt the performance of the galvanized steel and make it more vulnerable to rust, then it is more than a visual defect. 

Rust and corrosion are the biggest threats to steel and can cause it to weaken. If there is damage that will expose the steel to rust, it will have to be repaired before the piece can be part of a construction project.

• The second factor is more nuanced. Even if the visual defects of the galvanized steel do not hurt the quality, they can make the materials unacceptable for their intended purpose.  The AGA uses the example of a handrail with small bumps under the surface. The galvanized railing may still be perfectly corrosion resistant. But, its coating is still too low-quality for the setting.

What to Do If You Have Damaged Galvanized Steel

If you suspect you received poor-quality galvanized steel, you have a few options. 

First, photograph the defects as soon as you notice them. 

Then, call your manufacturer or galvanizer and share your concerns. Ask them about what options they have for repairing or replacing the pieces if they are unusable. A building inspector who specializes in the type of project you’re working on should be able to let you know if the galvanized steel item would pass inspection. 

When it comes to repairing galvanized steel, there are a few different options, depending on the size of the defect. 

If visual defects are present, they can often be repaired using zinc-rich paints, sprays, or soldering to restore the protective coating. These methods help maintain the material’s corrosion resistance while improving its appearance. 

Quality Galvanized Steel You Can Trust Every Time: South Atlantic’s Got You Covered

At South Atlantic, we do everything in our power to avoid defects of galvanized steel in our products. We not only meet and exceed ASTM standards for galvanized steel, but we also follow our own 25-step quality assurance process. 

As leaders in this industry for over 50 years, you know you can trust the products we manufacture and deliver to your construction site.

Learn more about our Galvanized Steel division today, then reach out to us to start your order. We look forward to working with you on your next project.