Necking out/raw necking out
In pipeline construction, branching and junctioning is increasingly being realized with necking.
They have a number of advantages over cast or welded purchased parts:
- improved flow properties
- lower weight
- Fewer joints in pipeline construction
- lower maintenance costs
- fewer complaints and leakages
- no storage costs
Necking principle
In the first step, an elliptical pilot hole is milled in the tube (left picture) . Then, the necking tool is used to slowly pull the pipe opening upwards until the characteristic opening is created (center picture). In the final operation, the drawn pipe connection is turned flat to remove unevenness for subsequent welding.