Problem
If the final closing of the tube is done imprecisely, the weld edges meet at the wrong angle or gap, producing off-center seams, poor penetration and out-of-round pipe.
Cause
The last forming passes determine the weld edge geometry, so any overshoot or undershoot there cannot be fixed by the welder and shows up directly as seam defects.
Solution
The ZY16 finishes forming in three precision stands that set the exact edge gap and approach angle before the weld point. Fine gap control gives the HF welder a consistent edge condition, producing a centered, fully fused seam on Φ8-18mm pipe, with roundness locked in before welding.
Key Engineering Data
- Three fine-adjust stands set the final weld edge gap.
- Controls edge approach angle for a centered, fully fused seam.
- Locks roundness before the HF weld point.
- Works with the rough stage for full-range Φ8-18mm control.
| Parameter | Specification |
|---|
| Mill Model | ZY16 |
| Tube OD Range | Φ8-18 mm |
| Wall Thickness | 0.4-1.0 mm |
| Strip Width Range | 25-57 mm |
| Max Line Speed | 90 m/min |
| HF Welder Power | 100 kW Solid-State High Frequency |
| Strip Material | Hot Rolled / Cold Rolled / Galvanized Steel |
| Uncoiler | Double-Mandrel Pneumatic, 1.5-Ton Coil Capacity |
| Accumulator | 200 m/min High-Speed Cage |
| Strip Leveling | Seven-Roller Leveling Unit |
| Forming Stands | 5-Stand Rough + 3-Stand Precision |
| Roller Geometry | Double-Radius Forming Rollers |
| Roller Shafts | 42CrMo High-Strength Alloy Steel |
| Safety | Forming Stand Overload Protection |
Performance & Quality
Three precision stands set the final weld gap and edge angle, so the HF welder sees a consistent edge condition. This produces a centered, fully fused seam and locks roundness before welding, which is why the ZY16 holds tight specs on Φ8-18mm precision tube.
Application
For Φ8-18mm pipe where weld seam straightness and penetration are critical, including precision, thin-wall and coated tube.
Selection Guide
Choose this configuration when weld consistency is your main requirement. The three precision stands work with the five rough stands to hold the weld gap within tolerance across the full Φ8-18mm range.
Application Scenarios
Precision mechanical tube, thin-wall tube with tight weld specs, and galvanized tube where a clean, centered seam is essential.
FAQ
Q1. What does the precision stage control?
It sets the final weld edge gap and approach angle so the HF welder sees a consistent edge condition for a centered seam.
Q2. Why three precision stands?
Three fine-adjust stands give the control needed to hold the weld gap tight without over-closing the tube.
Q3. Does it fix a bad rough forming stage?
No, the two stages work together; proper rough forming is required for the precision stage to finish correctly.
Q4. How is the weld gap set?
The precision rolls are profiled and adjusted per size so the edges meet at the correct gap and angle for your OD and wall.
Q5. How do I know the weld gap is set right?
The precision stands are set per size during commissioning, and you verify with the centered, fully fused seam on your first production coils.
Q6. Can I adjust the precision stands during a run?
Minor fine adjustment is possible, but major gap changes are done at tooling setup; the stands are designed for stable, repeatable settings.
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