1.Superior Rust Resistance
The main goal of galvanizing is to stop rust in its tracks—and that’s where the zinc oxide layer on galvanized steel comes in. Here’s how it works: the zinc coating corrodes first, taking the hit so the steel beneath stays intact longer. Without this zinc shield, metal would be far more prone to rust, and exposure to rain, humidity, or other natural elements would speed up the decay.
2.Extended Lifespan
This longevity stems directly from the protective coating. Research shows that, under typical circumstances, galvanized steel used in industrial settings can last as long as 50 years. Even in highly corrosive environments—think places with lots of water or moisture—it can still hold up for 20 years or more.
3.Improved Aesthetics
Most people agree that galvanized steel has a more appealing look than many other steel alloys. Its surface tends to be brighter and cleaner, giving it a polished appearance.
Where Galvanized Steel Gets Used
Different processes can be used for galvanizing:
2. Electro galvanizing
3. Zinc diffusion
4. Metal spraying
Hot-dip galvanized
During the galvanizing process, the steel is immersed in a molten zinc bath. Hot-dip galvanizing (HDG) involves three basic steps: surface preparation, galvanizing, and inspection.
Surface Preparation
In the surface preparation process, the pre-fabricated steel is sent for galvanizing and undergoes three cleaning stages: degreasing, acid washing, and fluxing. Without this cleaning process, galvanizing cannot proceed because zinc will not react with impure steel.
Galvanizing
After surface preparation is complete, the steel is immersed in 98% molten zinc at 830°F. The angle at which the steel is immersed in the pot should allow air to escape from tubular shapes or other pockets. This also allows the zinc to flow through and into the entire steel body. In this way, the zinc comes into contact with the entire steel. The iron inside the steel begins to react with the zinc, forming a zinc-iron intermetallic coating. On the outer side, a pure zinc coating is deposited.
Inspection
The final step is to inspect the coating. A visual inspection is conducted to check for any uncoated areas on the steel body, as the coating will not adhere to uncleaned steel. A magnetic thickness gauge can also be used to determine the coating thickness.
2 Electro galvanizing
Electrogalvanized steel is produced through an electrochemical process. In this process, the steel is immersed in a zinc bath, and an electric current is passed through it. This process is also known as electroplating.
Before the electrogalvanizing process, the steel must be cleaned. Here, zinc acts as the anode to protect the steel. For electrolysis, zinc sulfate or zinc cyanide is used as the electrolyte, while the cathode protects the steel from corrosion. This electrolyte causes zinc to remain on the steel surface as a coating. The longer the steel is immersed in the zinc bath, the thicker the coating becomes.
To enhance corrosion resistance, certain conversion coatings are highly effective. This process produces an additional layer of zinc and chromium hydroxides, resulting in a blue appearance on the metal surface.
3 Zinc Penetration
Zinc plating involves forming a zinc coating on the surface of iron or steel to prevent metal corrosion.
In this process, steel is placed in a container with zinc, which is then sealed and heated to a temperature below the melting point of zinc. The result of this reaction is the formation of a zinc-iron alloy, with a solid outer layer of pure zinc adhering to the steel surface and providing significant corrosion resistance. This coating also facilitates better paint adhesion on the surface.
For small metal objects, zinc plating is the optimal method. This process is particularly suitable for irregularly shaped steel components, as the outer layer can easily follow the pattern of the base steel.
4 Metal Spraying
In the metal spraying zinc plating process, electrically charged or atomized molten zinc particles are sprayed onto the steel surface. This process is carried out using a handheld spray gun or a special flame.
Before applying the zinc coating, all contaminants, such as unwanted surface coatings, oil, and rust, must be removed. After the cleaning process is complete, the atomized molten zinc particles are sprayed onto the rough surface, where they solidify.
This metal spraying coating method is the most suitable for preventing peeling and flaking, but it is not ideal for providing significant corrosion resistance.
How long does a zinc coating last?
Regarding durability, it typically depends on the thickness of the zinc coating, as well as other factors such as the type of environment, the type of zinc coating used, and the quality of the paint or spray coating. The thicker the zinc coating, the longer the lifespan.
Hot-dip galvanizing vs. cold galvanizing Hot-dip galvanized coatings are generally more durable than cold galvanized coatings because they are typically thicker and more robust. Hot-dip galvanizing involves immersing the metal in molten zinc, whereas in the cold galvanizing method, one or two layers are sprayed or brushed on.
In terms of durability, hot-dip galvanized coatings can last over 50 years regardless of environmental conditions. In contrast, cold-dip galvanized coatings typically last only a few months to a few years, depending on the coating thickness.
Additionally, in highly corrosive environments such as industrial settings, the lifespan of zinc coatings may be limited. Therefore, selecting high-quality zinc coatings and maintaining them over the long term is crucial for maximizing protection against corrosion, wear, and rust.
Post time: Aug-12-2025
