A Tube Mill Machine is a production system used to manufacture metal tubes and pipes from flat strips (coils) of material like steel, stainless steel, aluminum, or titanium. It does this by continuously forming, welding, sizing, and cutting the strip into round, square, or rectangular tubes.
Basic Working Principle
Flat strip → Forming → Welding → Sizing → Cutting → Final Tube
Step-by-Step Operation Breakdown
1. Uncoiling and Strip Feeding
A decoiler holds and feeds a coil of metal strip into the machine.
A straightener or flattener ensures the strip is free from bends or memory set.
Key Function: Prepare flat, smooth input material for forming.
2. Forming Section (Roll Forming)
A series of forming rolls progressively bend the flat strip into a round or shaped tube.
The forming process is gradual to prevent cracking or deformation.
Roll stations bend the metal into a "U", then "O", then fully closed circle (for round tubes).
3. Welding Section
The open edges are joined by high-frequency welding (HF/ERW) or TIG/laser welding, depending on the material.
In ERW (Electric Resistance Welding), electric current heats the edges, which are pressed together to form a seam.
In TIG welding, an arc melts filler (or just edges), protected by shielding gas.
The weld bead may be internally and externally removed (scarfing) for smooth finish.
4. Weld Seam Annealing (optional)
For materials like stainless steel or titanium, induction annealing is used to normalize the weld zone.
This improves corrosion resistance and reduces internal stress.
5. Sizing and Straightening Section
The now-welded tube is passed through sizing rolls to achieve:
Accurate outer diameter (OD)
Correct roundness/squareness
Straight alignment
This also shapes square or rectangular profiles from the round tube.
6. Cutting to Length
A flying cutoff machine cuts the moving tube into preset lengths.
Types of cutting:
Cold saw
Friction saw
Laser cutting
Burr-free rotary cutoff
Lengths are controlled automatically via PLC systems.
7. End Finishing (optional)
Tubes can be:
Deburred
Chamfered
Threaded
Hydrotested
Ultrasonically inspected
Main Components of a Tube Mill Line
| Section | Key Equipment |
|---|---|
| Uncoiling | Decoiler, flattener, shear welder |
| Forming | Forming rolls, vertical stands |
| Welding | HF welder, TIG welder, scarfing tools |
| Sizing | Sizing rolls, calibrator stands |
| Cutting | Cold saw, flying saw, rotary cutter |
| Automation & Control | PLC system, servo drives, HMI screen |
| Testing (optional) | Eddy current, hydrotester, X-ray |
Tube Mill Types (Based on Use)
| Type | Material | Applications |
|---|---|---|
| ERW Tube Mill | Carbon/Stainless Steel | Structural pipes, scaffolds |
| TIG Tube Mill | Stainless/Titanium | Medical, chemical, food tubes |
| Aluminum Tube Mill | Aluminum alloys | HVAC, auto, construction |
| Precision Tube Mill | Alloys, copper | Automotive, instruments, pens |
| Spiral Weld Tube Mill | Large pipes (steel) | Oil & gas pipelines |
Summary of How It Works
| Stage | Purpose |
|---|---|
| Strip Feeding | Provide raw flat material |
| Roll Forming | Gradually shape strip into tube |
| Welding | Join edges into a continuous pipe |
| Sizing | Calibrate shape and dimensions |
| Cutting | Produce fixed-length tubes |
| Finishing | Prepare tubes for final use or delivery |
