Dimensional Instability in Light Structural Tube
Structural tube for frames, racks and light construction must hold straightness and roundness so joints assemble square. Mills producing φ10-26mm sections often see end flare, bow and wall thinning at the weld, which raises assembly rework and weakens the finished frame under load.
Why Light Structural Tube Drifts Out of Shape
Single-radius forming over-works the strip edge and induces waviness, while an unguided seam produces uneven weld fusion and wall thinning. Residual heat that is not removed quickly enough leaves the body out-of-round and bowed, and worn roll shafts allow the pass profile to shift over time.
The ZY20 Structural Tube Mill Solution
A 7-roll leveler and double-radius pass with 5-stand rough plus 3-stand finish forming shape the strip evenly, so the weld enters the seam guide flat and centered.
Dedicated seam guidance with squeeze welding gives full fusion without wall thinning, and ≥10 t/h spray plus overflow-pool cooling locks roundness before the 6+6 sizing train.
A 4-roll Turk head straightens the finished section before the flying saw, delivering straight, square-ready tube at up to 90 m/min.
Technical Specifications of the ZY20 Tube Mill
| Parameter | Specification |
|---|
| Tube outside diameter | φ10–26 mm |
| Wall thickness | 0.4–1.5 mm |
| Rated production speed | up to 90 m/min |
| Raw material | HR / CR low-carbon steel, galvanized steel |
| HF welder power | 100 kW solid-state |
| Forming stands | 5 rough + 3 finish |
| Sizing stands | 6 horizontal + 6 vertical |
| Leveling rolls | 7-roll precision leveler |
| Cut length / precision | 4–8 m, ±3 mm |
| Coolant flow | ≥10 t/h spray + overflow pool |
| Roll shaft material | 42CrMo quenched & tempered + HF hardened |
Complete Continuous Production Process
Every ZY20 runs one continuous flow from coil to finished cut tube. An uncoiler feeds strip through a 7-roll precision leveler that removes coil-set, then double-radius forming shapes it in 5 rough and 3 finish stands without edge wave. A 100 kW solid-state HF welder fuses the seam under squeeze pressure with a dedicated seam guide, and an automatic outside-burr unit clears the bead immediately. ≥10 t/h spray plus overflow-pool cooling locks the shape, the 6-horizontal + 6-vertical sizing train sets the diameter, and a 4-roll Turk head straightens the tube before the microcomputer flying saw cuts 4–8m lengths to ±3mm. Overload-protected stands and 42CrMo hardened shafts keep the whole line stable over long runs.
Where the ZY20 Structural Tube Mill Is Applied
Light structural framing, rack and display structures, handrail and balustrade components, greenhouse and light construction sections in φ10-26mm round tube.
How to Select a Structural Tube Mill
Match your OD and wall to the ZY20 window of φ10-26mm and 0.4-1.5mm, define the straightness and roundness your assembly needs, then confirm HR, CR or galvanized coil and utility supply before installation.
Installation, Support and After-Sales
The ZY20 ships as a turnkey package with layout and foundation drawings so you can prepare the site before delivery. Engineer-led on-site installation and commissioning bring the line to rated output, with operator training to hand over a running mill. A one-year warranty with spare-parts support protects the investment, and because the line accepts HR, CR and galvanized coil, you can adapt to changing material costs and market demand without re-tooling.
Frequently Asked Questions About the ZY20 Structural Tube Mill
How straight is the finished tube?
The 4-roll Turk head straightens the section ahead of the flying saw for square, assembly-ready parts.
Does the weld thin the wall?
No — positive seam guidance plus squeeze welding keeps fusion complete without local wall thinning.
What sections can it run?
Round tube from φ10-26mm; the pass design can be discussed for your specific profile.
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