Does Brass Rust?

Brass is a metal used all across industry, from high precision valves to architectural and ornamental adornments. Its benefits are numerous, but does it rust?

In this article, we discuss the corrosion resistance of brass, how to care for it, and what to look out for to avoid corrosion-based failures.

Introduction to Brass Rust: What You Need to Know

Brass does not rust as such; that is, it does not corrode in the same fashion as steel, as it does not contain iron. Brass does tarnish and degrade, due to either oxidation or a process known as dezincification.

Oxidation happens in the same way as it does to other non-ferrous metals such as aluminum and copper. Oxygen in the air reacts with the base metal to form a dull oxide layer.

Dezincification is, as the name suggests, a chemical corrosion reaction in which the zinc is removed from the material, leaving behind just copper. This can have serious implications depending on the application.

The Corrosion Resistance of Brass: Factors that Influence Durability

Like most metals, different grades of brass are available, each with slightly differing properties and resistance to corrosion. The largest variable is the levels of zinc present, but other alloying elements such as lead and aluminum are commonly added too.

Marine grades of brass that are designed to resist corrosion from seawater are commonly alloyed with around 1% tin and have a relatively high percentage of zinc at 39%.

For components carrying water underground, most plumbing codes require grades known as DZR or dezincification resistant brass. These contain small amounts of arsenic and nickel – around 0.02% and 0.3% respectively, as well as having a low level of zinc, in the region of 15.

Common Causes of Brass Rust and Corrosion: Prevention Strategies

Along with correct material selection, there are other methods to prevent brass corrosion:

• Apply a protective coating: resin or polyurethane based clear coatings are available that help brass parts resist tarnishing and dezincification.
• Use appropriate grades: marine grades exist for use in harsh environments involving seawater, and other tailored brass alloys are available
• Reduce contact with the environment: by utilising multiple materials, a coating product and good design, the likelihood and consequences of brass corrosion can be limited

Maintenance Tips for Brass: Cleaning and Care Recommendations

Architectural brass can quickly tarnish through oxidization, but thankfully, it can be polished to a shine fairly easily. There are many commercially available products for this, but always be sure to check for adverse reactions on an inconspicuous area first.

Soft cloths or polishing pads are the best tools to apply polish or cleaning solution, as brass can be scratched easily with harsh abrasives.

When to Repair or Replace Brass Items: Signs of Severe Corrosion

On components that are purely for decorative purposes, replacement can be decided based on the part’s appearance. For more critical parts, such as valves, fasteners and mechanical components, a more robust quality control is needed.

A regular inspection schedule should be created, with trained personnel checking for the following:

• Changes in colour from yellow-gold to reddish-pink
• Cracks
• Porous surfaces
• Leaks or weeping of contained fluids
• Mineral stains or water spots caused by leaks

If any of the above are noticed, the part should be removed, inspected and a cost-benefit analysis conducted, with key emphasis on safety considerations if load or pressure are involved.

Buy Brass From Metals Supermarkets

Whether your project calls for flat sheet or plate, round bar or even hexagon bar, Metals Supermarkets can help. Check out all the available grades and shapes online, and have material cut and delivered nationwide.