INDUSTRY
Precision tube and heat-resistant grades for OEM and motorsport
Hydraulic precision tube, exhaust manifolds and bends, up to heat-resistant grades for motorsport. An industry where dimensional tolerance and repeatability matter as much as the grade.
ISO 1127 tolerances 310/310S · 321H Repeatable production runs
What you come to us for
A tolerance, before a grade. On precision tube destined for a cylinder or a mechanical assembly, the dimensional tolerance class determines machinability downstream — and drift between two runs is paid for in rework, not in claims.
On exhaust systems the constraint is thermal. A motorsport manifold runs at temperatures where a 304 distorts and scales; 310S and 321H are chosen for hot strength, not for aqueous corrosion — their PREN is low and carries no meaning here.
What we supply
Re-drawn precision tube, tube in heat-resistant and stabilised austenitic grades, to tolerances set at enquiry stage. For series production, sourcing directly from a partner mill guarantees consistency of source from one order to the next.
The ISO 1127 tolerance class is set at enquiry stage, according to diameter and grade. State the critical dimension — outside, inside or wall — rather than the class alone: that is what drives the choice of source.
Grades in this industry
| Grade | EN | Indicative PREN |
|---|---|---|
| 310/310S | 1.4845 | 24–28 † |
| 321H | 1.4541 | 18–20 ¹ |
| Re-drawn tube | — | — |
† PREN is calculable but not the deciding factor for this grade, see the note below · ¹ usual value from the technical literature, not drawn from a product standard.
PREN caveats (†)
- 310/310S
- ⚠️ PREN is NOT the relevant criterion for a heat-resistant grade. 310S is designed for hot oxidation resistance, not aqueous corrosion: without molybdenum, it isn't suited to chlorinated environments.
The grades listed are the most common in this industry, not a closed list. Every piping grade belongs to one of our nine families; if yours doesn't appear here, it is not outside our scope.
Applicable standards
Precision tube: ASTM A269, ISO 1127 dimensional tolerances. Heat-resistant grades: EN 10095, ASTM A312. Stabilised grades for hot service: ASTM A213, EN 10216-5.
Frequently asked questions
- What is re-drawn tube and when do you need it?
- Tube that has been through an additional drawing pass, which tightens dimensional tolerances and improves surface finish. It is used when the inside or outside dimension has to be held tighter than a standard tube guarantees — typically in hydraulics, or ahead of machining.
- Why a 310S rather than a 316L on an exhaust?
- Because the criterion is resistance to high-temperature oxidation, not aqueous corrosion. 310S, at 25% chromium and 20% nickel, withstands temperatures at which a 316L degrades. Its PREN is low and carries no meaning in this application.
- Can you guarantee the same source from one run to the next?
- On mill-sourced supply, yes: that is the main reason to use that route for series production. From partner stock, the source depends on availability at the time of order — tell us if consistency of source is a requirement.
- Do you handle short runs?
- Yes. We have no minimum quantity as a matter of principle. Volume determines the supply route — stock or mill — and therefore lead time and price, not our ability to quote.
Tell us what you need: grade, size, quantity, deadline. Same-day response on a simple enquiry, within 2 to 3 working days on a complex one.
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