Which Tubes Can Be Spin Closed? How Material, Weld Seam, Wall and Ductility Affect Closing
Spin closing gradually gathers the tube end with forming rollers at room temperature – it is cold forming. With no heat and no welding, the tube itself decides whether closing works and how good the result is.
Tube conditions that matter
| Condition | Effect |
|---|---|
| Material and ductility | Carbon steel, stainless, aluminium and copper can all be closed, but the material must be ductile enough; hard material tends to crack at the closure |
| Weld seam | On seamed steel and stainless tubes the seam must be sound, or it will split during closing |
| Wall thickness | Diameter and wall must suit each other – too thin wrinkles, too thick is hard to form; each model has its working range |
| Incoming tolerance | Cold forming carries the tube's own tolerance into the part; tighter incoming tolerance gives more stable closed ends |
| Surface condition | Oil and rust affect forming and appearance; keep tube ends clean before closing |
Common causes of cracking
- Material too hard or not ductile enough.
- A weak weld seam.
- Diameter and wall outside the machine's working range.
- Tooling or forming settings not suited to the tube.
How to confirm your tube can be closed
The most reliable way is a sample trial: send the tube specification and closed-end drawing, and a trial on your actual tube shows the appearance, dimensions and any cracking.
Related machines: TD-31040 hydraulic 3-station, TD-21025 flat-end, TD-382 CNC servo.
Why TONG DA
- TONG DA has designed and built tube processing machines since 1989 and runs contract processing on its own machines.
- Tooling is designed to your tube and drawing; sample trials available.
- CE certified; machines sold to the USA, Germany, Turkey, the UK, India, China and more.
FAQ
Can stainless tube be closed?
Yes – softer stainless forms more easily; a sample trial is recommended.
Does closing discolour or anneal the tube?
No heat is used, so stainless does not discolour from heating.
How do I arrange a closing trial?
Send the tube OD, wall, material, length and closed-end drawing to sales@tdco.com.tw and we will reply promptly.