Tube material and determining proper wall reduction

When it comes to tube reduction, you need to be able to determine the reduction of the walls. Additionally, you have to understand the characteristics of tubing materials. A general rule to keep in mind is that the harder a material is, the less wall reduction you need to get a tube joint.

Below, we have some information to help with calculating a wall reduction percentage. They are guidelines and general suggestions for working with tubes.

Admiralty Brass

This type of Brass is very common in condensers. If you want optimum tube joints, you should look at reducing the wall by around 7-8%. Generally, reducing wall thickness by 4-10% will create a tight tube in a serrated hole. However, more than 15% can result in splits, leaking, and flaked tubes.

Carbon Steel

People use Carbon Steel in most pressure vessels today. Any tube wall reduction should be around 7-8%. Make sure you check the hardness of the tubing if there is any cracking or if your tooling is showing excessive wear.

Copper & Cupro Nickel

You should consider reducing walls around 8-10% when rolling Cupro Nickel and Copper to produce a proper tube joint. Because copper is a softer material choice for tubes, it is fairly easy to work with.

Titanium & Stainless Steel

If you are rolling Titanium or Stainless Steel tubes, reducing walls by approximately 4–5% is enough to make a secure joint. These alloys can work harden so you should complete any wall reduction quickly. It is wise to use a 4 or 5 roll expander when rolling Titanium. This is in order to eliminate tube end cracking and decrease the diaphragm of a thin wall.


tube reduction

You won’t want to reduce walls by more than 5% if you are rolling 3003 or 4004 Aluminium. If you are working with 6061-T, a substance which is very popular for aircraft fittings, you can reduce walls by 10-12% for a mechanical joint.

Multiform completes tube reduction with precision. We also offer many other forms of tubing manipulation to cater for our clients. Reach out now and a member of our highly experienced team will talk to you about your specifications.