Roll tooling is the first thing to wear and the last thing buyers think about — and it decides the shape of every metre of pipe you make. We design the pass line, machine the rolls on our own CNC lathes, vacuum heat-treat them and finish them in-house, so a new set arrives with the profile you approved rather than a copy of whatever was on the shelf.
What We Design
- Breakdown and forming rolls — the first passes that turn flat strip into a round section without marking the surface.
- Fin passes and welding rolls — the squeeze rolls and fin rolls that set the weld V and hold the edges together at the weld point.
- Sizing and Turk's head rolls — the final passes that bring the tube to diameter, roundness and straightness.
- Square and rectangular tube roll sets — corner radii and flat-face quality set for furniture, construction and structural sections.
- Quick-change roll sets and stands — so a size change is a cassette swap instead of a shift of shimming.
- Spare and replacement rolls — single rolls or complete sets for machines already in production, including lines we did not build.
How the Design Process Works
- 1. You send the job — tube diameter and wall range, material, line speed, and the mill make and model if you have one.
- 2. We model the pass line — roll profiles, flower pattern and strip width are worked out and checked before anything is cut.
- 3. You approve a roll drawing — profile drawings come to you for sign-off, so there are no surprises at the machine.
- 4. We machine, harden, grind and ship — with the roll set marked for stand and pass, plus fitting notes for your fitters.
Machining, Heat Treatment & Inspection
Rolls are turned and milled on CNC lathes and machining centres, hardened and vacuum heat-treated in our own furnace, then finished and checked for profile, concentricity and surface finish before they are packed. Because the tooling shop, the heat treatment and the assembly benches sit on the same site, a replacement roll does not wait for a third party’s schedule.
Ordering a Roll Set Without a Drawing
Most roll enquiries arrive without a drawing, because the mill was bought second-hand or the original tooling drawings were never handed over. That is normal, and it is workable. The pass can be reconstructed from the machine plus the product, and the product is the easier half.
What we need to rebuild a pass line:
- Tube outside diameter, wall thickness and the material grade.
- The stand it fits: number, shaft diameter, roll bore, roll width, keyway or friction mounting.
- The pass number, or a photograph of the worn roll with a rule against it.
- Strip width your slitter supplies, and the tolerance it holds.
- If available, the profile depth measured at the contact line on the worn roll.
From that, the flower pattern is re-derived, the passes are laid out, and the drawing is sent for your approval before any steel is cut. If the mill has been re-shimmed since the rolls were made, say so: a pass copied from a worn sample without allowing for that reproduces the error.
Regrinding: When It Saves Money and When It Moves the Problem
A roll can be reground while the groove still has enough depth to hold the profile. The rule of thumb is that the working surface can come down until the profile is within about 0.3 mm of its minimum, after which the pass no longer forms the section and the roll is finished.
| Symptom | Regrind? | Why |
|---|---|---|
| Polished wear band, profile still measurable | Yes | Cheapest correction available |
| Edge pick-up and galling | Yes, plus polish | Surface condition, not geometry |
| Profile depth below minimum | No | The groove can no longer form the section |
| Cracks at the keyway or bore | No | Scrap, and a warning about the shaft fit |
| Uneven wear across the face | Investigate first | Usually alignment or strip camber, not the roll |
Regrinding also changes the pass line height on that stand. If you regrind a full set, the change is uniform and the line still runs; if you regrind one stand, the pass line steps and the tube will show it. Record the ground amount on the roll card and adjust the stand shims by the same figure.
Roll Life Is Mostly Decided by the Strip
Two plants running the same roll set on the same tube size get different life, and the difference is almost always the strip: scale, edge condition, camber, and whether the coil was pickled. A roll that runs 8,000 tonnes on clean pickled coil may run 3,000 on a scaly hot-rolled coil with a rough edge. This is why we ask about the strip before quoting a roll set, not after the first complaint.
Spare Sets, and Which Size to Keep
- Keep one spare set for the size that runs most often — that is the size where a wear failure stops the plant.
- Keep the finishing pass as a separate spare if you run tight tolerance work; it is the pass that decides ovality.
- Do not keep a spare of every size. The capital sits on a shelf while the size you need is the one that changed.
A spare set also halves the changeover argument: with a pre-set set on a trolley, the mill can change size while the worn set goes for regrinding, instead of waiting for it.
From the Knowledge Centre
- From Flower Pattern to Finished Pass
- Roll Material and Heat Treatment
- Reading Roll Wear: When to Resharpen and When to Replace
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