Galvanized Square Steel: What Is It, When To Use It & Where To Buy

Pre-galvanized steel is a great material; it’s perfect for making corrosion-resistant covers, brackets, and other parts, both in the shop and in the field. Galvanized square tubing is even more useful, as it enables the creation of support structures and frames without the need for painting.

But how is galvanized square steel made, what are some common uses for it, and where is it best to source it from?

What is Galvanized Square Steel Tubing and How Is It Made?

Square tube is one of the most commonly used materials in engineering and fabrication. Its high strength to weight ratio and its flat sides make it a simple material to use for making fabricated items such as frames and brackets.

Square tube starts as a round tube, which itself begins as a flat sheet, being passed through incremental stages of rolling until the desired shape is achieved. The tubes are then galvanized.

There are two types of galvanizing, hot dip and electroplating. Both involve coating the surfaces with zinc, but the former does so by dipping the parts in a bath of molten zinc, and the latter uses an electrolysis process to coat the metal using an electric current.

Key Advantages of Using Galvanized Square Steel

• Strength/Weight ratio: square tube has a high strength to weight ratio, making it useful for load bearing applications
• Corrosion resistance: the galvanizing protects the steel from corrosion, allowing it to be used in outdoor applications without needing paint
• Maintenance free: In applications where wood or painted mild steel might be used, galvanized steel offers the benefit of never needing to be treated/painted in the future
• Quick to deploy in the field: any other method of making a bolted structure would require painting or other coating to protect it

Common Applications of Galvanized Square Steel Tubing

Galvanized square tubing can be found in all manner of applications, anywhere a reliable, low maintenance, strong material is needed!

• Fencing: fence posts are commonly made of galvanized square tube for their strength and ease of connecting to
• HVAC framework: frames and support structures need to be corrosion resistant, and galvanized square tube allows technicians to construct them on site
• Rigging: in large buildings or theatre settings galvanized tube is often used as a cost-effective mounting material for lights, speakers and more

Factors to Consider When Choosing Galvanized Square Steel

Galvanized square tube is specified in much the same way non galvanized steel is, by the physical dimensions and material grade.

• Outside shape: both rectangular and square tubing is available
• Outside size: sizes typically range from 20mm to 100mm
• Thickness: the wall thickness can range from 2mm to 4mm in certain sections

All three of the parameters above affect the strength of the tube, but in certain cases, the tube dimensions are constrained by other parts of the assembly, in which case the wall thickness can be increased or decreased to improve strength or reduce weight.

If the strength to weight ratio is of the utmost importance, it might be worthwhile to consider a round galvanized tube, as round tubes are inherently stronger than square; they also have the benefit of being able to use the various types of clamping systems available.

Where to Buy Galvanized Square Steel Tubing: Top Suppliers

Many places stock galvanized square tube, as it is a commonly used material for many industries. A local steel merchant or stockholder is likely to be happy to sell you full lengths, although you may need to open an account with them.

Another option is to buy direct from Metals Supermarket, they have a wide range of both galvanized sheet, round and square tube. There are no minimum length requirements, and a cut-to-size service is offered nationwide.

Check where your nearest store is using the store locator here.