Angle Iron: The Ultimate Guide to Sizes, Uses, and Buying Tips

Angle iron is a favourite of engineers, fabricators and designers worldwide, thanks to its versatility and low cost. It offers great strength in multiple directions and a multitude of mounting options when used in a wider assembly.

If you’re thinking of using angle iron in your project, this guide will explain all there is to know about sizing, selecting and designing for metal angle iron.

Understanding Angle Iron Sizes: A Comprehensive Guide

Like all metal sections, angle iron comes in a wide range of sizes. There are three critical dimensions to be aware of when deciding what size angle iron to use:

• A Leg length 1
• B Leg length 2
• C Thickness

Equal and Unequal Angles

Angle iron is available in both equal (e.g., 50mm x 50mm x 5mm) and unequal (e.g., 50mm x 75mm x 6mm) leg lengths. The designated thickness (e.g., 5mm) is always the same across both legs, regardless of whether the angle is equal or unequal.

What sizes of angle iron are available?

Metals Supermarket offers anything from 13mm x 13mm and 3mm thick, up to 200mm x 200mm in 20mm thick, quite a range! Naturally, these sizes go up in increments, such as 5mm, 10mm or 50mm.

Top Uses for Angle Iron in Construction and DIY Projects

You’ll find angle iron being used for all sorts of things. It is one of the cheapest metal sections that can be used both in tension and compression. These are some common uses in construction and DIY.

• Frameworks for equipment – things such as control panels, enclosures and housing frameworks are often made of angle.
• Bracketry – if you need to mount something perpendicularly, a small piece of angle iron with some holes drilled in makes a strong and fast mounting solution.
• Structures – Angle is often used in the construction of building structures, bridges, portal frame buildings and more.

Angle Iron Material Types: Choosing the Right One for Your Needs

Angle iron is available in all the common engineering materials, including but not limited to:

• Mild steel
• Galvanized steel
• Stainless steel
• Aluminum

Mild Steel angle iron

The most commonly used angle iron is in steel, thanks to its high strength but very low cost. Typically, angle iron is available in the following grades:

• S235
• S275
• S355

Other grades are available, but these will be the easiest to get. Galvanized angle iron is also widely available, great for using to make brackets and components in the field, where minimal painting or finishing is ideal.

Stainless steel angle iron

Stainless steel is made into most of the same section shapes as mild steel, including angle iron. It offers the same benefits as steel, but with excellent corrosion resistance. The most commercially available grades of stainless angle are 304 or 316 grade.

Angle Iron Buying Guide: Factors to Consider for Best Value

Angle iron can be an extremely versatile and cost-effective material, as it comes with one of the lowest per-metre rates of any section, but it’s still important to consider value when using it.

Thanks to its simple design, angle is cheaper than both square and round tubes per metre, but not as strong per kg. This means you may find your overall assembly weighing more when using angle iron compared to square tube. This, in turn, can increase secondary costs such as transport or finishing, both of which are often affected by weight.

Another cost implication of using mild steel angle iron is finishing, left uncoated, mild steel will rust in most outdoor environments. Galvanized angle can be used to mitigate this, providing a pre-protected material, perfect if no welding is required.

Angle Iron Installation Tips: Ensuring Strength and Safety

If you’re planning to use angle iron for anything mission-critical, it’s important to ensure the proper installation and design methods are followed.

Angle iron is strong in both tension and compression, but being an asymmetrical section, care should be taken when used in a compressive application to avoid buckling.

Similar attention should be paid to load paths and bolted connections, again, as the shape is not uniform across its X axis. In some cases, an extra piece of angle iron can be welded to the end, over the bolt holes, to form a stronger box-section like shape, increasing strength significantly.