Metal tubes come in various shapes and sizes. As a result they are suitable for a huge array of different applications. This includes continuous systems such as handrails or pipe lines. To make these you will likely need to be able to slot individual sections of tube together. You will also need to be able to attach them to other fittings and fixtures. One way to allow this is tube expansion.

How does it work?

The expansion process is really effective and does not require a great deal of extra working. The process literally involves pushing a die into the end of the tube. This can be one of two types. The first will taper so that it will gradually open the tube as the die moves further into the tube. The other option is a segmented die that opens and closes rapidly to literally hammer the inner surface of the tube.

Expanding the tube will increase the inner diameter so the opening is wider. This can then allow another piece of tube or a fixture or fitting to slot inside. You can open the tube varying degrees so you can create a tight joint.

What does it mean for the wall thickness?

The goal with tube expansion is to open the tube end without affecting the wall thickness. As a result it should remain consistent around the circumference, even at the now expanded section.

The concern with expansion is that the compression will result in thinner walls towards the tube end. If this happened it could compromise the strength and stability of the tubing. Luckily, Multiform has the skills to ensure this does not happen. We also take care to maintain the shape of the tubes so they remain consistent after expanding. As a result with round tubing there should be no flat spots or other flaws.

Thicker walls are harder to expand

One thing to think about is that the wall thickness can actually restrict how much you can expand a tube. It is naturally harder to expand thicker wall tubes because there is more material. You may still be able to have some tube expansion, it just might require more pressure to insert a tapered die or more force from a segmented one.

When planning expansion you should consider the wall thickness and as well as the type of material you are working with. This is especially true if it is a substance like stainless steel that is subject to work hardening. These substances get harder as you work them. As a result you may have even more restrictions in terms of how much you can expand the tube.

Talk to us about tube expansion

If you are using tubing and need to alter it in any way, rely on Multiform Tubes. We are a team of experts with access to a wide array of great equipment. Whatever you need, we are confident we can cater for your needs.

You can contact us if you have any questions about tube expansion. We are happy to help.