The Galvanized Steel Inspection Process: Protecting Your Investment

The galvanized steel inspection process is critical for both manufacturers and customers alike. Galvanizing is a unique process that covers steel in a corrosion-resistant zinc coating. Careful inspection throughout the process ensures that the resulting products maintain their quality and durability. 

There are clear industry standards outlined by the American Society for Testing and Materials (ASTM) that dictate how galvanized steel should look and perform. Manufacturers are required to meet these minimum standards. Any step skipped in this inspection process can result in inferior galvanized materials hitting the market. That puts public safety at risk and hurts the projected lifespan of the projects that use these materials.

Experience and in-depth knowledge are the most important qualities to look for in a galvanizer. A seasoned galvanizing company will know the process well enough to identify issues quickly and address them in the appropriate manner. In this article, we’ll look at how galvanizing works, how the inspection process guides the manufacturing of galvanized materials, and what can go wrong.

If you are ready to work with galvanized steel experts for your upcoming construction project, then reach out to our team at South Atlantic. 

A Quick Look at the Steps of the Galvanizing Process

Galvanizing steel happens in three basic stages: preparation, galvanization, and then inspection. While a final round of testing and inspection does happen at the end of the process, there are also quality checks throughout to make sure the steel is responding correctly.

The Preparation Stage

In the preparation stage, the raw steel is degreased and pickled. This removes any dirt, oil, sediment, or paint from the steel. Before pickling, the steel can also be sandblasted to remove any tough debris. The pickling is the final “cleaning” process and preps the surface of the steel to receive the zinc coating.

The Galvanizing Process

Then comes the galvanizing process. Before dipping the steel into the molten zinc, the pieces are dipped in a flux solution. This solution helps prevent rust from forming underneath the zinc coating. Once that dries, the steel is ready for the molten zinc bath. It is immersed in the bath, allowing every inch of the steel to be completely encased in the zinc. It is then set out to dry and harden.

Potential Areas of Concern

Throughout this process, there are a few things that can go wrong. If the preparation stage is not handled well, dirt or oil can prevent the zinc from adhering to the steel. The final coating can appear bumpy and uneven. Or, the coating may be thinner than desired for the project.

How Does the Galvanized Steel Inspection Process Work?

Catching the issues we mentioned above is the job of the inspection process. By evaluating coating thickness, performing visual inspections to identify defects, and testing adhesion to verify the coating’s strength, the manufacturer can make sure his galvanized materials will be reliable.

Measuring the Galvanized Steel Zinc Coating Thickness

Why is the zinc coating thickness measured? It is measured because the coating thickness of the galvanized steel is most important for its performance. The thickness determines the durability and lifespan of the galvanized steel. While thicker is not always better, the heaviest coating possible for the project at hand is ideal.

The inspector or manufacturer uses a magnetic thickness gauge to take measurements across the galvanized steel. At least five readings taken from different sections are required to guarantee accuracy. There are a few guidelines for measuring galvanized steel correctly. These include avoiding holes or edges and measuring flat sections instead of rounded ones. 

The required minimum thickness depends on the steel. The American Galvanizers Association explains: 

“The specifications (ASTM A123, A153, and A767) give requirements concerning the minimum zinc coating for a given material class during the hot-dip galvanizing process.”

Completing the Inspection: Testing Adherence and Appearance

Once the steel passes the coating thickness test, there are two other tests to complete the inspection. The adherence test makes sure that the zinc has bonded with the steel and is not just sitting on top of it. To prove this, a knife is run down the side of the galvanized steel. While it will mark the steel, it should not cause it to flake, move, or chip.

Finally, the galvanized steel undergoes a visual inspection. The manufacturer looks over the steel to check for any obvious bumps, ridges, or uncoated sections. These can indicate weak points in the coating that can compromise structural integrity or aesthetic appeal.

If the coating thickness is consistent and meets requirements, the zinc has reliable adherence to the steel, and the coating looks smooth and even, then the galvanized steel inspection process is complete.

What Happens When Galvanized Steel Fails Inspection?

Galvanized steel can fail inspection for several reasons. These include:

• Imperfect zinc coverage
• Inconsistent coating thickness
• Visible defects 

When any of these things happen, they can threaten the performance of the galvanized steel materials. Whether or not the imperfections can be repaired depends on the size of the imperfections and the intended purpose of the steel.

How Can Flawed Hot-Dip Galvanized Steel Be Repaired?

The most common, repairable imperfection is a thin or uncoated section of the steel. If the inspection process reveals a small section of bare steel, there are three options for covering it. 

• The first is using a zinc-based alloy solder on the area to repair the coating or increase its thickness. 
• The second is covering the area with zinc-rich paint. 
• The third option is to metalize or “zinc spray” the area, which is similar to spray-painting the area with molten zinc.

There are very strict rules dictating how many imperfections can be repaired after galvanization. If these imperfections are not addressed or too many are allowed, the galvanized steel can fail in the field. This poses significant safety risks, decreases durability, and threatens compliance with industry standards.

 It is best to work with a manufacturer who takes the galvanized steel inspection process seriously so you can avoid these headaches in your project.

How South Atlantic Protects Your Investment with a Strict Galvanized Steel Inspection Process

At South Atlantic, we take great pride in the quality of our galvanized steel. We are unwilling to compromise, which is why we offer in-house galvanizing services. We only sell our customers galvanized products we are certain meet both industry standards and ours.

To this end, we strictly follow all ASTM standards. We have a rigorous 25-point quality assurance process that each of our galvanized steel products must pass before we sell it. For our regular inventory of steel products, we source our materials from top American steel manufacturers to ensure we can offer our customers the highest quality materials. We also offer Kettle Tags to make sure you receive the steel products you ordered and ensure nothing is mixed up during the galvanization process.

With over 50 years in the galvanization industry, we have been able to fine-tune the galvanization and ordering process to best serve our customers. Our careful process, combined with our expertise, means your steel will be galvanized with accuracy you can count on, every time.

Call South Atlantic Galvanizing Today for Your Upcoming Construction Project

At South Atlantic Galvanizing, we’ve got you covered. From superior galvanizing services to the management of every step, from order to delivery, we make it easy for you to galvanize any steel you need for your construction project. 

To learn more about our galvanizing services and request a free quote, fill out our contact form here. One of our experienced team members will be in touch soon.