Does Galvanized Steel Rust?

Does Galvanized Steel Rust?

Galvanized steel is a popular material used in structural, structure piping, sheet metals, and other applications due to its durability and resistance to corrosion.

However, many people wonder whether galvanized steel rusts or not. The answer is both Yes and No.

Before you know the answer, first understand what is Galvanization and you will be able to answer it yourself.

What is Galvanization Process?

Galvanization is a process of coating metal with zinc in order to protect it from corrosion.

By preventing the underlying metal from rusting, galvanized steel and other metals can last much longer than their non-coated counterparts.

This process involves coating the metal with a layer of zinc, which acts as a barrier between the metal and its environment, protecting it from oxidation and other forms of the chemical attack.

Image courtesy:

The galvanization process typically starts with cleaning the surface of the metal by removing dirt, oils, and other contaminants that could affect adhesion.

After this is completed, a layer of zinc is applied using either hot dip galvanizing or electroplating.

Hot dip galvanizing involves submerging the metal into molten zinc while electroplating deposits a thin layer onto its surface through an electrical current.

This process has been used for centuries to create durable products, but it has become increasingly common in the modern era due to its affordability and effectiveness.

The galvanization process is often used for products such as steel beams, steel pipes, nuts and bolts, and even wires.

So, Does Galvanized Steel Rust?

The short answer is that Yes, galvanized steel will rust over time. This type of steel contains a thin layer of zinc which helps protect the underlying layer of material from the elements and corrosion.

However, the zinc coating on galvanized steel will wear out eventually, leaving the metal exposed to water and oxygen which can cause it to corrode and rust.

While the corrosion process may take longer than with regular steel due to the zinc coating, it is still possible for galvanized steel to start showing signs of wear over time.

When exposed to water or moisture, either through rain or dew, the zinc coating on the surface of the metal can start to erode over time.

This leaves the underlying steel vulnerable to rusting if it hasn’t been treated with additional protective measures such as paint or sealants.

It’s also important to note that galvanized steel can corrode if exposed regularly to severe weather conditions such as saltwater environments or areas with high acidity levels in the air or soil.

Read more: What is Corrosion & Its Types.

Galvanizing of Steel

The galvanizing technique involves coating the surface of the steel with a layer of zinc in order to provide a protective barrier against rusting, which can be damaging over time.

The galvanising process uses either a hot-dip method or an electroplating procedure, depending on the desired outcome.

A hot dip galvanised finish requires that the steel is immersed in molten zinc at temperatures exceeding 460°C.

This ensures complete coverage and superior protection from corrosion, as well as providing an aesthetically pleasing finish for architectural purposes.

With electroplating, the metal object is dipped into an electrically charged solution containing zinc ions which cling to the surface and form a bond with it; this method also produces a visually appealing result and offers good resistance against wear and tear.

How long does it take for Galvanized steel to rust?

Galvanized steel is coated with zinc, which helps to protect the steel from rust and corrosion.

The amount of time it takes for galvanized steel to rust will depend on several factors, including the thickness of the zinc coating, the environment in which the steel is located, and the type of steel.


Generally, galvanized steel can last for several decades without showing significant signs of rust.

However, if the zinc coating is damaged or worn away, the steel underneath can begin to rust in as little as a few years.

How long does galvanized steel last outside?

Galvanized steel is a popular material used for outdoor structures and fixtures due to its incredible durability.

But how long exactly does galvanized steel last outside?

The answer may depend on the environmental conditions, but in general, galvanized steel can last anywhere from 10-20 years without any maintenance.

The lifespan of galvanized steel depends on various factors such as exposure to moisture, extreme temperatures, UV rays, thickness of the zinc coating, and the environment in which it is located.

If the environment is mild with minimal exposure to harsh weather conditions or chemicals, then galvanizing can offer long-term protection against corrosion and rusting.

On the other hand, if exposed to more extreme conditions like high humidity or frequent rainstorms then the coating may deteriorate faster leading to corrosion over time.

In addition to that, if the zinc coating is damaged or worn away, the steel underneath can begin to rust in as little as a few years. Factors such as acid rain, high humidity, and salt air can also shorten the lifespan of galvanized steel.

Additionally, regular maintenance such as paint touch-ups or rust removal will extend its longevity even further.

How to protect Galvanized steel from rusting?

Here are some tips on how you can protect your galvanized steel from rusting.

  1. Keep it Clean: Regularly cleaning the steel can remove dirt, dust, and other contaminants that can cause rust to form.
  2. Paint it: Applying a coat of paint to the steel can provide an additional layer of protection against rust and corrosion.
  3. Use a rust inhibitor: Rust inhibitors are chemical compounds that can be applied to the steel to prevent rust from forming.
  4. Avoid Scratches: Avoiding scratches on the surface of the steel can help to prevent rust from forming.
  5. Keep it dry: Keeping the steel dry can help to prevent rust from forming, as moisture is one of the main causes of rust.
  6. Store it properly: Proper storage of the steel can help to prevent rust from forming.
  7. Apply a rust-inhibiting oil: To protect the steel from rusting, a rust-inhibiting oil can be applied to the surface of the steel.

Does Galvanized steel rust in water?

The simple answer to this question is yes, galvanized steel does rust in water.
This occurs because when the zinc coating on the metal oxidizes, it changes the composition and allows oxygen and moisture to penetrate into the metal underneath.

Also, if the zinc coating is damaged or worn away, the steel underneath can rust in water. The zinc coating on galvanized steel is not completely waterproof, and over time, the zinc can be corroded by exposure to water.

Does Galvanized steel rust in saltwater?

Saltwater environments, such as marine or coastal areas, can be particularly harsh on galvanized steel.

The salt in the water can cause the zinc coating to break down more quickly, exposing the steel underneath to rust. Additionally, the salt can also cause “white rust” as mentioned below.

Does Galvanized steel rust in the ground?

When buried in the ground, galvanized steel is exposed to different types of soil and chemicals which can cause the zinc coating to corrode over time.

The corrosion rate of galvanized steel in soil will depend on the soil’s pH level, the presence of salt, and the level of oxygen in the soil.

What is White rust?

Galvanized steel is also susceptible to a phenomenon called “White rust” which is caused by the presence of water and high humidity, it appears as a white powdery substance on the surface of the steel.

White rust is not as damaging as red rust (result of corrosion) but it can weaken the zinc coating if it’s not addressed.

Material Welding is run by highly experienced welding engineers, welding trainers & ASNT NDT Level III bloggers. We strive to provide most accurate and practical knowledge in welding, metallurgy, NDT and Engineering domains.