When wire mesh needs to withstand moisture, weather, and everyday wear, galvanized steel is often a reliable choice. The coating provides the steel with an added layer of corrosion protection without sacrificing the strength and versatility that make steel useful in so many applications. But the question everyone likely has is this: “Does galvanized wire rust?”
The short answer is yes, but not as quickly as uncoated steel. Galvanized wire can resist corrosion for years because the zinc coating acts as a protective barrier, shielding the steel beneath. How long that protection lasts depends on factors such as the environment, coating thickness, moisture, salt, chemicals, and physical damage. In this article, we will look at why galvanized wire mesh eventually corrodes, how long it can last, what causes rust, and how to extend its service life.
Why Does Galvanized Wire Mesh Rust or Corrode?
Galvanized steel is steel coated with zinc. The zinc creates a protective barrier between the underlying steel and the surrounding environment. This is why galvanized steel has better corrosion resistance than uncoated carbon steel. The zinc coating also provides a second form of protection. Zinc is more chemically active than steel, so it can corrode preferentially and provide sacrificial protection to exposed areas of the underlying steel.
However, that protection does not last forever.
When galvanized steel is exposed to moisture and air, the zinc surface gradually reacts with the environment and develops corrosion products known as a zinc patina. Under normal atmospheric conditions, this patina is relatively stable and helps slow further corrosion of the zinc coating.
But over time, the zinc coating becomes thinner. If enough zinc is consumed or the coating is damaged, the underlying steel can become exposed. At that point, the familiar reddish-brown rust associated with steel can develop. This means that galvanized steel is corrosion resistant, but it is not completely corrosion proof.
How Long Does It Take for Galvanized Wire to Rust?
There is no single answer to how long it takes for galvanized steel to rust because the zinc coating does not disappear at the same rate in every environment.
The American Galvanizers Association reports that atmospheric corrosion rates for zinc vary considerably depending on factors such as humidity, rainfall, temperature, air pollution, and salinity. Field testing across rural, suburban, industrial, tropical marine, and temperate marine environments has demonstrated significant differences in galvanized coating performance.
For Lawrence Sintered Metals customers, the relevant environments can include construction, agriculture, architecture, automotive, food and beverage, oil and gas, pharmaceutical, and other industrial applications.
Outdoor and General-Purpose Applications
For ordinary outdoor applications where the mesh is exposed to rain and humidity but not unusually aggressive chemicals or salt, galvanized steel can provide many years of protection. But also, actual service life depends on the conditions of use.
Industrial Environments
Industrial environments can accelerate zinc corrosion when the surrounding atmosphere contains pollutants or other corrosive substances. The American Galvanizers Association identifies humidity and sulfur dioxide pollution among the factors that influence zinc corrosion.
This is particularly relevant when galvanized mesh is used around industrial processing, manufacturing, or other environments where corrosive contaminants may be present.
Marine and Coastal Environments
Salt and chloride exposure can significantly increase corrosion. Marine environments therefore require more careful material selection than ordinary outdoor applications.
The American Galvanizers Association specifically identifies air salinity as a factor affecting zinc corrosion and notes that aggressive chlorides can affect the protective zinc patina. If mesh will be exposed regularly to salt water, marine spray, or another highly corrosive environment, galvanized steel may not be the best material. Stainless steel or a more corrosion-resistant alloy may be more appropriate depending on the application.
Oil, Gas and Chemical Applications
Lawrence Sintered Metals serves the oil and gas, chemical, pharmaceutical, and other industrial sectors where corrosion resistance can be an important design consideration.
For these applications, the expected service life of galvanized wire cannot be determined from the industry name alone. The actual fluid, temperature, humidity, chemical concentration, exposure time, and mechanical conditions all matter. For demanding filtration or corrosive process environments, stainless steel and specialty alloys may provide a better long-term solution than galvanized steel.
What Causes Rusting or Corrosion in Galvanized Wire Mesh?
Several factors can reduce the life of galvanized wire mesh, and they include:
Environmental Exposure
Moisture is one of the primary drivers of atmospheric corrosion. Repeated wet and dry cycles cause the zinc surface to react with the environment. Humidity, rainfall, temperature, air pollution, and salt exposure can all influence the rate at which the coating is consumed.
Constant exposure to moisture can be particularly demanding because the zinc has less opportunity to remain in its stable protective condition.
Salt and Chlorides
Saltwater and chloride-rich environments are especially aggressive toward metals. Coastal air, road salt, marine spray, and direct contact with saltwater can increase corrosion rates.
If your mesh will operate in a marine environment, it is worth discussing the application with a mesh supplier before selecting galvanized steel.
Zinc Coating Thickness
Not every galvanized product has the same amount of zinc protection. Coating thickness affects how much zinc is available to protect the underlying steel.
ASTM International (formerly American Society for Testing and Materials) specifications establish requirements for zinc coatings on various galvanized steel products, including fabricated wire work. When corrosion resistance is important, the coating specification should be considered alongside the wire diameter, mesh construction, and service environment.
Physical Damage
Cutting, bending, welding, abrasion, and impact can damage the galvanized coating.
Once steel is exposed, the zinc around the damaged area can still provide some sacrificial protection. However, repeated mechanical damage can reduce the effectiveness of the coating and create areas where corrosion can develop.
This is particularly important when mesh is installed in applications where it will be handled frequently or exposed to abrasion.
Chemical Exposure
Some chemicals can accelerate corrosion of zinc. The exact effect depends on the chemical, its concentration, temperature, and exposure conditions. For instance, a galvanized coating that performs well on an outdoor fence may not provide the same service life inside a chemical processing system.
For applications involving corrosive chemicals, material selection should be based on the actual operating environment rather than simply choosing galvanized steel because it has good general corrosion resistance.
Poor Storage Conditions
Galvanized mesh can also develop surface staining when moisture becomes trapped between tightly packed surfaces during storage. Proper storage and ventilation can help reduce problems associated with prolonged moisture exposure.
How to Prevent Galvanized Wire Mesh From RustingÂ
You cannot make galvanized steel completely immune to corrosion, but you can take steps to extend its service life. Here are some ways to prevent galvanized wire mesh from rusting quickly:
Choose the Right Coating
Start with a galvanized product that has a coating appropriate for the intended environment. Coating thickness matters because a thicker zinc layer generally provides more material to consume before the underlying steel is exposed.
Match the Material to the Environment
Consider the actual conditions the mesh will experience.
A galvanized mesh may be a practical choice for general outdoor, agricultural, construction, fencing, screening, and other applications. More aggressive environments may call for stainless steel or a specialty alloy.
Lawrence Sintered Metals supplies stainless steel, galvanized steel, plain steel, aluminum, copper, brass, bronze, and other materials to meet different application requirements.
Minimize Physical Damage
Ensure galvanized mesh is handled and installed carefully by professionals. Avoid unnecessary abrasion and damage to the coating. If the mesh needs to be cut, bent, welded, or otherwise fabricated after galvanizing, consider how the exposed areas will be protected.
Keep the Mesh Clean
Dirt, debris, salt, and other contaminants can hold moisture against the surface. Regular cleaning can help maintain the coating, particularly in outdoor or industrial applications.
Consider an Additional Protective Coating
In demanding environments, galvanized steel can sometimes be used as part of a multi-layer corrosion protection system. The galvanized surface can also be prepared for painting or powder coating using appropriate procedures.
For example, a duplex coating system can provide an additional barrier while retaining the underlying protection provided by zinc.
Applications of Galvanized Wire Mesh
Galvanized wire mesh is useful when an application requires the strength of steel with additional resistance to outdoor corrosion.
Common applications include:
- Fencing and gates
- Window and security screens
- Hardware cloth
- Garden and agricultural barriers
- Machine guards
- Partitions
- Building and architectural components
- Drainage and screening applications
- Storage and material handling
- Ventilation screens
- Protective barriers
Galvanized mesh can also be fabricated into components such as wire mesh discs. These discs can be used for inline filtration and inside pipes, tubes, ducts, and other filtration systems.
For more demanding industrial applications, however, material selection becomes increasingly important. The right mesh depends on what the material needs to withstand.
Where to Buy Galvanized Wire Mesh in the United States
If you are looking for galvanized wire mesh in the United States, work with a supplier that can help you select the right material, mesh size, wire diameter, and configuration for the application.
Lawrence Sintered Metals has supplied wire mesh, wire cloth, and sintered wire mesh for more than 30 years. We serve customers throughout the United States as well as international customers, with both in-stock and custom mesh solutions available.
Our wire mesh inventory includes galvanized steel, stainless steel, plain steel, aluminum, copper, brass, bronze, and specialty alloys. This gives customers the flexibility to select a material based on the actual requirements of their application rather than choosing galvanized steel by default.
If you are unsure whether galvanized mesh will provide enough galvanized steel corrosion resistance for your project, we can help you evaluate your requirements and determine which mesh material makes sense. Contact Lawrence Sintered Metals to discuss your application or request a quote.