If you’ve ever bought steel pipe, you’ve probably come across the term ERW. But what does it actually mean, and is it the right type of pipe for your project?
ERW stands for Electric Resistance Welded. It’s one of the most commonly used steel pipes in South Africa because it’s strong, reliable, readily available and cost-effective.
Whether you’re building a shed, fabricating a trailer, installing irrigation, or working on a large construction project, there’s a good chance you’re using ERW pipe.
How is ERW pipe made?
ERW pipe starts life as a flat strip of steel that’s welded into a tube. As the edges come together, an electrical current heats the steel and pressure joins the two edges into a solid weld. No filler material is used.
Once the pipe has been welded, it’s sized, straightened, cut to length and inspected before leaving the mill.
The end result is a pipe that’s consistent in size and suitable for a wide range of applications.
What is ERW pipe used for?
One of the reasons ERW pipe is so popular is its versatility.
You’ll find it being used for:
• Structural steelwork
• Agricultural equipment
• Trailer manufacturing
• Irrigation systems
• Fencing
• Handrails
• General engineering
• Factory maintenance
• Fire protection systems
• DIY projects
For most everyday fabrication and construction work, ERW pipe is the go-to choice.
Is ERW pipe strong?
Yes.
There’s sometimes a misconception that because ERW pipe has a welded seam, it’s weaker than seamless pipe. Modern manufacturing has come a long way, and today’s ERW pipe is used in demanding structural and industrial applications every day.
The important thing is choosing the correct size, wall thickness and grade for the job.
If you’re unsure, ask your supplier before buying.
ERW vs seamless pipe
This is probably the question we’re asked most often.
Seamless pipe is manufactured from a solid billet of steel, so it doesn’t have a welded seam. Because of this, it’s generally used for specialised applications involving very high pressure or temperature.
For the majority of projects, though, ERW pipe is the more practical choice. It’s easier to source, costs less and performs exceptionally well in structural and general engineering applications.
Unless your specification specifically calls for seamless pipe, ERW is usually the right option.
Can ERW pipe rust?
Like any mild steel product, it can.
If the pipe is exposed to the weather without protection, it will eventually corrode.
Depending on where it’s being used, you can improve its lifespan by:
• Hot-dip galvanising
• Painting
• Powder coating
• Choosing pre-galvanised pipe where appropriate
The best option depends on the environment and the intended use.
Can ERW pipe be welded?
Yes.
ERW pipe is easy to cut, weld, drill, thread and fabricate, which is one of the reasons it’s so widely used in workshops and fabrication businesses.
Choosing the right ERW pipe
Not all steel pipe is the same.
Outside diameter, wall thickness and steel grade all affect how the pipe performs. Using pipe that’s too light for the job can lead to unnecessary failures, while using heavier material than you need simply adds cost.
If you’re not sure what to buy, it’s worth getting advice before placing your order.
Need help?
At Steel Pipes & Fittings, we’ve been supplying steel to businesses, farmers, contractors and DIY customers since 1993.
If you’re unsure which pipe is right for your application, get in touch with our team. We’ll help you choose the right product for the job, whether you need a single length or a truckload.