Why Hot-Dip Galvanizing is Steel’s Superhero

Don’t dip out — this is going to be a good read! We’re talking about the hot topic, hot-dip galvanizing (aka HDG).

Hot dip?! Like cheese dip? No, cheese dip doesn’t have anything on this … That’s because we all know cheese dip never lasts. But galvanized structures certainly do.

So, let’s galavant right into what hot-dip galvanizing is.

“Hot-dip galvanized steel is produced by dipping bare steel in a bath of molten zinc metal. A protective coating is formed by a metallurgical reaction between iron and zinc, providing both a barrier and cathodic protection that protects the steel from corrosion,” the experts at GalvanizeIt.org write. 

For us outside of the galvanizing industry, this means steel goes into a bath and comes out with a defensive layer against damage. AKA, wax on, don’t wax off. 

Below, we explore the benefits, application, and longevity of hot-dip galvanizing. What it is, what it does, and why you need it.

THE BENEFITS OF HOT-DIP GALVANIZING

Does steel get a sense of well-being from a soak in a hot zinc bath? Kind of, but not exactly. Here’s a quick rundown of why steel deserves a hot dip. 

• All-weather protection
• Corrosion protection throughout
• Arcing and bending prevention

Let’s dive deeper into each of these three benefits, exploring the top reasons behind hot-dip galvanizing steel. 

1. SUPERMAN STRENGTH

Holy hot-dip, Batman! Hot-dip galvanizing offers unmatched durability in extreme environments, such as underwater, buried in soil, near waterways, and in the baking sun. 

“The three biggest factors in hot-dip galvanizing’s durability are abrasion resistance, uniform protection, and complete coverage.”¹

Just think about what would happen if the bridges you drive on weren’t galvanized! They would rust and ultimately fail. So, that’s a no-go, and we’re all super grateful now for hot-dip galvanized infrastructure.

2. CORROSION’S ARCH ENEMY 

When steel is hot-dip galvanized, that means it’s fully submerged in molten zinc. This silvery zinc liquid coats all the nooks and crannies of the metal.  

Galvanizing metallic structures in a zinc bath. Photo by BogdanVj.

“This complete coverage ensures even the insides of hollow and tubular structures and the threads of fasteners are coated. As corrosion tends to occur at an increased rate inside hollow structures where humidity and condensation occur, interior coverage is very beneficial. Fully coating fasteners are equally important as they are utilized at connection points critical to structural integrity.”¹

We at Natina are all about what’s on the inside matching, what’s on the outside, too. Our color solution can go on every piece of galvanized metal (and rock and concrete) on your project. Seriously, every piece — inside and out.

On left: Galvanized steel with Natina finish.

3. THE PROTECTOR WE ALL NEED

Ever seen steel transported on a semi-truck on the highway or installed on a construction site? This process isn’t always a smooth one because delivery can be a literal and metaphorical bumpy road. And it doesn’t stop there. After installation, Mother Nature likes to take a toll, too. See our post about Monsoons for more on that! 

So, that said, hot-dip galvanizing is key to sturdy steel, making a huge difference in arcing and bending prevention: “Hot-dip galvanizing’s abrasion resistance provides unmatched protection against damage caused by rough handling during transport and erection, as well as in service.”¹

Rough and tough is a hot-dip dream. But, how does hot-dip galvanizing give steel all of these benefits? Read below for more information about the application. (Hint: It forms layers, not to be confused with comic supervillain’s lairs.) 

THE APPLICATION OF HOT-DIP GALVANIZING 

We’ve “covered” the details of hot-dip coating, but here’s a glimpse of what’s below the surface.  

“A unique characteristic of the Hot-Dip Galvanized coating is the development of tightly-bonded (~3,600 psi), abrasion-resistant intermetallic layers. The cross-section of a galvanized steel coating shows the three intermetallic layers (Gamma, Delta, and Zeta) and the top layer of pure zinc (Eta). During the galvanizing process, these layers develop naturally during a metallurgical reaction between the iron in the steel and zinc in the kettle.”¹

Cue: Ooohhhh. Cue: Ahhhhh. 

Now we all want those layers because when the steel has been hot-dip galvanized, it lasts a long, long time.  

THE LONGEVITY OF HOT-DIP GALVANIZED STEEL 

The reason to choose hot-dip over leaving steel bare is longevity. If you want your steel to last longer than the dinosaurs (close, right?), hot-dip galvanizing is the way to go. 

“In addition to the bond strength, which is approximately 3,600 psi, the way the coating develops is key to its long-term durability. The galvanized coating grows evenly … and covers all surfaces, ensuring its abrasion resistance is all-encompassing.”¹

Hot-dip galvanized steel has a long life, generally corroding at a rate of 1/30 of bare steel in the same environment!² With such a long lifetime, that makes hot-dip galvanizing a sustainable choice for steel, postponing the need for replacement. 

BUT WAIT, THERE’S MORE

Are you interested in learning more about hot-dip galvanizing? Check out a video from the American Galvanizers Association. 

WHERE NATINA DIPS IN

If you want a rustic and natural look on hot-dip galvanized metal, then think Natina! We help change how you see construction, blending steel into its natural surroundings with our color solutions.  

Sources

¹ https://galvanizeit.org/hot-dip-galvanizing/why-specify-galvanizing/durability 

² https://galvanizeit.org/hot-dip-galvanizing/why-specify-galvanizing