If you’re planning a project that involves strong, affordable structural components, mild steel RHS is likely one of the first materials you’ll come across. Known for its balance between strength and versatility, mild steel RHS (Rectangular Hollow Section) is widely used in construction, fabrication, infrastructure, and general engineering applications across Australia and the world.

In this guide, we’ll walk you through what mild RHS is, why it’s such a popular material, its common uses, and how to select the right size and thickness for your project.

What Is Mild Steel RHS?

Mild steel RHS refers to rectangular hollow steel sections made from mild steel. These are tubular products with a rectangular cross-section and are typically cold-formed or hot-rolled, depending on the grade and application.

Mild steel is a low-carbon steel that’s easy to cut, weld, and form—making it cost-effective and ideal for a wide range of structural and mechanical uses. When shaped into RHS, it combines excellent load-bearing capacity with a simple form that is easy to handle and install.

Why Use Mild Steel RHS?

There are many reasons why mild steel RHS is preferred by builders, engineers, and fabricators:

1. Excellent Strength-to-Weight Ratio

Despite being lightweight compared to solid steel sections, mild RHS maintains high compressive and tensile strength. It performs well under load, making it ideal for structural support.

2. Versatile and Adaptable

From agricultural equipment to industrial frames and residential fencing, RHS made from mild steel can be used almost anywhere. Its adaptability is one of the biggest advantages.

3. Easy to Cut, Weld, and Fabricate

One of the main reasons mild steel is so commonly used is that it’s easy to work with. RHS sections can be joined, bent, or cut using standard tools and techniques.

4. Cost-Effective Option

Compared to other alloys like stainless steel or aluminium, mild steel RHS is much more budget-friendly, both in terms of material costs and fabrication expenses.

Common Applications of Mild Steel RHS

Mild steel RHS (Rectangular Hollow Sections) is widely recognised for its versatility, making it a popular choice across many industries. Thanks to its balanced combination of strength, formability, and affordability, mild RHS is used in countless construction and fabrication projects—from light-duty home builds to heavy industrial applications.

1. Structural Frameworks for Buildings and Infrastructure

One of the most common uses for mild steel RHS is in structural framing. Its rectangular shape provides excellent strength-to-weight ratio, making it ideal for beams, columns, and bracing systems. Whether for residential houses, warehouses, or commercial buildings, mild RHS helps create solid frameworks that meet Australian standards and load requirements.

2. Fencing, Gates, and Protective Barriers

Because of its straight edges and ease of welding, mild steel RHS is also frequently used in fencing and gate construction. It delivers a neat, uniform appearance while being sturdy enough to handle impacts, weather, and daily use. With the right coating or galvanisation, these steel sections resist corrosion and maintain their appearance for years.

3. Outdoor Structures: Carports, Pergolas & Shelters

For DIY builders and professionals alike, mild steel RHS is a go-to material for outdoor frameworks like pergolas, carports, gazebos, and patio roofs. Its ability to support long spans without sagging makes it perfect for open structures. It’s easy to cut and weld on-site, which reduces time and costs during installation.

4. Furniture and Industrial Frames

In the world of industrial and commercial furniture, mild steel RHS provides the skeleton for desks, shelving units, benches, and storage racks. It’s often chosen not just for its strength but also for its clean, boxy aesthetic that suits modern interior and industrial design trends.

5. Agricultural Equipment and Utility Trailers

Farmers and agricultural manufacturers often rely on mild steel RHS for constructing trailers, feeders, machinery frames, and other farming equipment. Its durability and cost-effectiveness make it ideal for rural applications where performance is essential and budgets are tight.

6. General Fabrication and Custom Projects

From signage and steel art to machine guards and display structures, mild steel RHS is used in general fabrication work where both strength and appearance matter. The flat surfaces allow for easy attachment of panels, connectors, and other components—making custom designs much easier to achieve.

Available Sizes of Mild Steel RHS

Mild RHS is available in a wide range of sizes, wall thicknesses, and lengths. These can include:

Note: Sizes may vary based on region and supplier.

Always check with your supplier for stock availability or request custom lengths if needed.

How to Choose the Right Mild Steel RHS for Your Project

Choosing the right mild steel RHS depends on several factors:

1. Load-Bearing Requirements

For structural applications, calculate the load-bearing needs of your build. Heavier loads will require thicker wall sections and larger sizes.

2. Indoor vs Outdoor Use

Mild steel can corrode over time if exposed to moisture. If you’re using RHS outdoors, make sure it’s hot-dip galvanised or powder-coated for corrosion protection.

3. Aesthetics

Since RHS sections have clean, flat lines, they are often used where a neat appearance is desired. Choose sizes that visually complement your design.

4. Fabrication Needs

Consider how easy the section will be to cut, bend, or weld. Thicker walls may be stronger but harder to work with manually.

Protecting Mild Steel RHS from Rust

Unlike stainless steel, mild steel isn’t naturally corrosion-resistant. But that doesn’t mean it can’t be used outdoors or in harsh conditions. Here are some protection options:

• Galvanising: A zinc coating that prevents rust
• Powder Coating: Offers colour and added corrosion protection
• Oil Coating: For temporary protection during transport or storage
• Painting: Economical for general applications

Where to Buy Mild Steel RHS in Australia

You can find mild steel RHS at most local steel suppliers, building material stores, or metal distribution companies. Many suppliers offer custom cutting services, and some even provide delivery directly to your job site.

If you’re sourcing steel for a project in Perth or regional WA, contact us for a fast quote, reliable stock, and expert advice. We offer a wide range of RHS sizes and finishes, and we can help you choose the right one for your needs.

Conclusion: Mild Steel RHS Is a Solid Choice

Mild steel RHS is a staple in the world of construction and fabrication. It’s affordable, strong, and easy to work with—making it a go-to choice for professionals and DIY builders alike. By understanding your project’s structural needs and environmental conditions, you can confidently select the right size and finish of mild RHS for a job done right.

Need Help Finding the Right RHS?

Send us your project specs or drawings, and we’ll help you choose the ideal mild steel RHS—and provide a fast, no-obligation quote.

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