How Sellers Mislead You with ‘Galvanised’ Steel

Don’t get fooled by the “galvanised” label. Many sellers take advantage of the buyer’s lack of technical knowledge, and this may cost customers significantly in the long run. But not anymore. 

The term “galvanised” means that a layer of zinc has been applied to steel to protect against corrosion. But how that zinc is applied makes a massive difference in durability and cost of the product. 

Galvanisation has two major types: electro galvanised and hot dip galvanised. You may only realise what electro galvanised and hot dip galvanised really mean when your steel starts rusting after 2–3 years. 

When you unknowingly purchase non–hot-dip galvanised steel, thinking it’s protected, at first, it looks fine, but then it starts rusting in just a few years. The paint peels, the coating bubbles, and the structure begins to weaken. That’s when it hits you: not all “galvanised” steel is the same.

If you're investing in a product that needs to last, you need to know the difference between electro galvanised and hot dip galvanised steel. In this post, I’ll share which is better: electro galvanised vs. hot dip galvanised? What's the difference between them?

So next time you come across these terms, you’ll know what they mean and which one you should choose. Without further ado, let’s get into it.

What is Galvanised?

Galvanisation is a process of applying a protective zinc coating to steel or iron to prevent rusting and corrosion. Galvanised coating acts as a barrier between the metal and the environment. The term "galvanised" is often used as a general description for any zinc-coated metal.

Galvanising can be done in different ways, but the most common methods are electro-galvanising and hot-dip galvanising. When people say "galvanised," they often mean electro-galvanised (less commonly used). It is a process where zinc is electrochemically deposited onto metal/steel using an electric current. This creates a smooth, thin, and even layer of zinc.

Types of Galvanisation

1. Hot Dip Galvanising: Immersion of steel in molten zinc (discussed in detail below).

2. Electro Galvanizing: An Electroplating process where zinc is deposited onto the steel using an electric current.

3. Pre-galvanised: Sheet metal processed through continuous galvanising lines before fabrication.

4. Mechanical Galvanising: Cold process where zinc is mechanically bonded to the substrate.

5. Zinc Spraying (Metallising): Molten zinc is sprayed onto the surface of the metal.

Many sellers sell “galvanised” products. Due to unawareness, customers often don’t know whether it’s electro galvanised or hot dip galvanised. As mentioned above, both are different processes and offer different levels of durability. Hot-dip galvanised steel provides longer durability than electro-galvanised and is slightly more expensive (but cheaper in the long run).

GEZU IMPEX clearly mentions whether the product is hot dip galvanised or electroplated, so the customer gets the right product at the right price. Many competitors don’t mention this, and it ends up costing the customer when the product starts to corrode after a few years.

So, beware of this and ask before you buy. This way, you get the right coated product for your project. Just seeing the words “galvanised steel” on a label isn’t enough.  

What is Electro Galvanising?

Electroplating involves coating a thin layer of zinc through an electroplating process (electrolytic cell). This method uses a zinc salt bath and electric current. The item to be coated is placed in a solution containing metal ions. When an electric current is applied, the ions move and form a layer on the surface of the item.

Features of Electro Galvanising (Electroplated Zinc Coating)

• Corrosion Resistance: The zinc coating sacrificially corrodes instead of the base metal, providing cathodic protection.

• Coating Thickness: Min 8–20 mm

• Appearance: Smooth, shiny or dull silver depending on finish

• Application Method: Electroplating in zinc salt solution using electric current

• Coverage: Uniform on simple shapes; less so on complex geometries

• Bonding: Electrochemical Bond

• Temperature Requirements: Ambient to low temperatures; no heating required

What is Hot Dip Galvanised (HDG)?

Hot dip galvanising is a specific galvanisation process. In this method, steel is dipped into a bath of molten zinc at high temperatures. This creates a much thicker, rougher and more durable coating compared to electro-galvanising (galvanising).

So basically, hot dip galvanised is a type of galvanisation. But it’s more effective than galvanised steel because it provides a thicker coating, stronger bonding, and longer-lasting protection.

Features of Hot Dip Galvanised Coating:

• Complete Coverage: The entire surface is coated, including recessed areas, inside corners, and hard-to-reach sections

• Thickness: Min 55mm (thicker than electro-galvanising)

• Appearance: Crystallised "spangle" pattern, slightly rougher texture

• Application Method: Immersion in a molten zinc bath

• Coverage: Complete coverage, including recessed areas and inside hollow sections

• Bonding: Metallurgical bond with zinc-iron alloy layers

• Temperature Requirements: Requires heating steel to approximately 850°F (450°C)

Process of Hot Dip Galvanising:

• Surface Preparation: Thorough cleaning through degreasing, acid pickling, and fluxing.

• Immersion: Complete submersion in a bath of molten zinc (≈450°C).

• Metallurgical Reaction: Formation of zinc-iron alloy layers.

• Withdrawal: Removal from the zinc bath, allowing excess zinc to drain off.

• Cooling: Air or water quenching.

• Inspection: Quality control checks for coating thickness and appearance.

Differences Between Electro Galvanised and Hot Dip Galvanised Steel

Here are the most common differences between hot dip galvanising and electro galvanising:

Advantages and Disadvantages of Electro Galvanised vs. Hot Dip Galvanised Steel

Both galvanising methods protect metal from rust, but they don’t perform the same in every situation. Below are the electro galvanised vs. hot-dip galvanised steel advantages and disadvantages.

Advantages of Electro Galvanising

• Precise Thickness Control: Can be adjusted to exact specifications

• Smooth Finish: Aesthetically pleasing

• Excellent for Post-Processing: Parts can be easily welded, formed, or bent after coating

• Tight Dimensional Tolerances: Minimal change to the original dimensions

• Unexpensive: Less expensive than hot-dip galvanising

• Ideal for Smaller Components: Works well for fasteners, fittings, brackets, and small parts

Disadvantages of Electro Galvanising:

• Limited Corrosion Protection: Thinner coating means shorter lifespan in harsh environments

• Less Durable: More susceptible to scratches and physical damage

• Shorter Service Life: Typically lasts 5-10 years in moderate environments

• Less Effective in Extreme Conditions: Not ideal for marine environments or chemical exposure

• Weaker Edge Protection: Coating is thinner at corners, edges, and threads

Advantages of Hot Dip Galvanising

• Superior Corrosion Protection: Can last 25+ years even in challenging environments

• Self-Healing Properties: Zinc can protect small scratches through cathodic protection

• Complete Coverage: Protects interior surfaces of hollow structures

• Excellent Impact and Abrasion Resistance: Harder, more durable surface

• Low Maintenance: Rarely requires touch-ups or reapplication

• Cost-Effective Long-Term: Lower lifetime cost due to extended service life

Disadvantages of Hot Dip Galvanising:

• Higher Initial Cost: More expensive upfront than electro galvanizing

• Rougher Finish: Less aesthetic appeal for visible applications

• Dimensional Changes: Can slightly alter dimensions due to coating thickness

• Limited Post-Processing: More difficult to weld or form after coating

• Not Suitable for Precision Parts: May interfere with tight tolerances

• Size Limitations: Restricted by the size of the zinc bath

So Which One Should You Choose?

There's no one-size-fits-all answer here, but I can help you figure out which approach makes the most sense for different situations.

Go with hot dip galvanised steel when:

• Your metal will be exposed to outdoor conditions

• You need decades of maintenance-free protection

• The item will be used in coastal areas 

• You're working with structural components like fencing, railings, scaffolding or building frames

• The somewhat rougher finish doesn't matter for your application

Choose electro galvanized steel when:

• You need a smooth, consistent appearance

• The metal needs to be bent, welded, or formed after coating

• You're working with smaller, precision parts

• The application is primarily indoors or in less corrosive environments

• You need tight dimensional tolerances

I’d recommend hot dip galvanised steel as the better option. While both processes involve similar materials, hot dip galvanising generally has a better environmental profile over the long term. It’s more durable and offers higher corrosion resistance compared to galvanised steel.

Your Most Frequently Asked Questions Answered!

Which is better, galvanised or hot-dipped galvanised?

Hot-dip galvanised steel is better than regular galvanised for outdoor and industrial use due to its thicker, more durable coating. Galvanised steel is better suited for indoor use or applications needing a smooth finish.

Does hot-dip galvanising weaken steel?

No, hot-dip galvanising does not weaken standard steel. The process involves dipping steel into molten zinc, which forms a protective coating without altering the core strength of the steel. However, in high-strength steels, the heat can sometimes cause slight distortion or reduce ductility, but this is rare and usually manageable with proper planning.

Can Galvanised Steel Rust?

Yes, galvanised steel can rust over time, but it takes much longer than regular steel. Galvanised steel is coated with a protective layer of zinc that prevents rust by shielding the steel from moisture. How fast it rusts depends on the coating type. Hot dip galvanised steel has a thicker zinc coating and can resist rust for 25+ years, while electro galvanised steel has a thinner coating and may rust sooner as compared to hot dip galvanised steel.

Is hot-dip galvanised rustproof?

Hot-dip galvanising provides excellent rust protection. The zinc coating protects steel through barrier protection, cathodic protection (where zinc corrodes instead of steel), and the formation of a zinc patina that seals the surface over time.

Make Your Decision

So there you have it — the complete rundown on electro galvanised vs. hot dip galvanised. As you can see, hot-dip galvanising is the best solution for protecting your metal components. If you’re looking for something that will truly stand the test of time in tough outdoor conditions, hot dip galvanising is hard to beat. Check out our range of hot-dip galvanised products and find the perfect solution for your project today!