Smooth, bright, bead-free bore. The alternative to seamless tube.
The Delmàs PRECISE range is high-precision welded steel tube with maximum inner and outer diameter control and a smooth, bright bore. It directly replaces seamless extruded tube in the vast majority of industrial applications, with significant cost savings and immediate availability.
The perfect bore extruded tube promised, now at its real cost.
For decades, when an application required a perfect tube bore — a gas damper, a hydraulic cylinder, a cooling circuit — the answer was always the same: seamless extruded tube. Not because it was the only possible technical solution, but because it was the only one known.
Seamless tube's three real problems
Seamless extruded tube has a seam-free bore, which historically gave it the edge in high inner-precision applications. But it has three problems its users know well.
- Cost: Between 40% and 80% more expensive than the equivalent precision welded tube.
- Lead time: Significantly longer delivery times. In special diameters, they can reach months.
- Availability: In diameters outside the standard catalogue — the ones many applications require — seamless tube is scarce or unavailable.
The PRECISE range demonstrates that the absence of a weld seam is not a technical requirement of the application — it is a historical legacy. What the application requires is a smooth, precise, irregularity-free bore. And that is exactly what PRECISE delivers.
From steel coil to tube with mirror bore.
Five steps controlled in-house: from base steel to delivery with smooth, bright, certified bore.
Raw material
Steel coil selected by grade, purity and mechanical properties to guarantee the mirror bore finish.
Precision welding
High-technology ERW process. The inner seam is formed with maximum control from the very first millimetre.
Outer calibration
Outer dimensional control with ±0.05 mm tolerance. Without compromising the inner finishing process.
Mirror bore finishing
Proprietary Delmàs process: the inner surface is brought to mirror finish, free of bead and irregularities. The differentiator of the range.
Certified delivery
Certificate with composition, mechanical properties, verified inner and outer dimensions and applicable standard.
The highest technical demand inner in welded tube.
The PRECISE range is the only Delmàs range with a mirror bore. Designed to replace seamless extruded tube in high inner-precision applications.
| Parameter | PRECISE Specification | |
|---|---|---|
| Manufacturing process | High-precision welded steel tube with calibrated inner and outer diameter | |
| Outer diameter (OD) | 8 mm – 25 mm (including non-standard sizes on request) | |
| Wall thickness | 0.50 mm – 8.00 mm | |
| Dimensional control | Inner and outer diameter — maximum precision | |
| Inner finish | Smooth and bright surface — mirror-type bore, bead-free | |
| Outer finish | Precision-calibrated outer surface | |
| Standards | EN 10305-2 · ASTM 513 Type 5 · ASTM 513 Type 6 · JIS G3445 | |
| Supply formats | Standard length · Coil · Cut-to-exact-length · Finished part ready to assemble | |
| Main applications | Gas dampers · Low-pressure hydraulics · Cooling · Pneumatics | |
| Standard | Market | What it defines for PRECISE |
|---|---|---|
| EN 10305-2 | Europe | Precision steel tube with calibrated inner diameter. Defines inner dimensional tolerances, mechanical properties and inner surface quality requirements. The reference standard for gas dampers, hydraulic cylinders and applications where the piston slides directly on the tube bore. |
| ASTM 513 Type 5 | USA/Global | ERW tubing with high-precision inner calibration (Drawn Over Mandrel — DOM). Inner-control level equivalent to EN 10305-2 for the American market. Required by damper and hydraulic component manufacturers with North American homologation. |
| ASTM 513 Type 6 | USA/Global | Top level of the ASTM 513 standard for welded tube with maximum-precision bore. For applications requiring the greatest inner dimensional control within the American standard. Comparable to the most demanding EN 10305-2 specifications. |
| JIS G3445 | Japan/Asia | Japanese standard for welded steel tube for mechanical use. Covers high inner-precision applications in the Japanese and Asian markets. Relevant for Japanese carmakers and their global supply chains. |
The product certificate is issued with every delivery and includes steel composition, batch mechanical properties, verified inner and outer dimensions, and the applicable standard for the order. It is not an additional document: it is our standard delivery.
| Parameter | PREMIUM | OPTIM | PRECISE ★ Mirror bore |
|---|---|---|---|
| Bead-free bore | ✗ Not applicable | ✔ ≤ 0.15 mm | ✔ Mirror — bead-free |
| Inner finish | — Standard | Controlled | Smooth and bright |
| Outer Ø control | ✔ High precision | ✔ High precision | ✔ High precision |
| Inner Ø control | ✗ Not applicable | ✔ High precision | ✔ Maximum precision |
| Technical equivalent | — | — | Seamless extruded tube |
| Available diameter | 3–13 mm | 3–10 mm | 8–25 mm |
| Primary standard | EN 10305-3 | EN 10305-3/2 | EN 10305-2 |
| Ideal application | Surface finishes | Axles, wheels, mechanisms | Gas springs, hydraulics, dampers |
There are three levels of inner control in precision welded steel tube. The PRECISE range occupies the most demanding level: mirror bore, technically equivalent to seamless extruded tube.
Four formats, adapted to your process.
For gas damper and hydraulic cylinder applications, cut-to-exact-length is the most common format: the length of the cylinder body directly determines the piston's stroke.
Standard length
Standard-length bars. For cutting and machining processes at the client's plant.
Coil
Continuous coil. For cooling-coil and continuous-circuit manufacturing lines without stoppages for bar changes.
Cut-to-length Recommended
Exact length with tight tolerance. Cylinder body length is critical for piston stroke.
Finished part
PRECISE tube as the base for a transformed part: cutting, bending, end tapering. Ready to receive the piston directly.
What the application needs is not the absence of a seam. It is the perfect bore.
The PRECISE range demonstrates that the absence of a weld seam is not a technical requirement — it is a historical legacy. What the piston needs is a smooth, precise, irregularity-free bore. And that is exactly what PRECISE delivers, at a fraction of the seamless cost.
Seamless extruded tube
- Perfect bore — but at 40–80% higher cost
- Lead times of weeks or months in special diameters
- Limited availability outside the standard catalogue
- Extrusion process generates significant material waste
- High MOQs imposed by steel manufacturers
- No downstream transformation capability at source
Delmàs PRECISE range
- Smooth bright bore — technically equivalent to seamless
- Availability in weeks, not months — in the diameter you need
- Diameters 8–25 mm including non-standard sizes on request
- Precision welding process with minimal material waste
- Flexible orders without punishing MOQs — pilot order possible
- Transformation capability: cutting, bending, tapering, finished part
The saving is not only on price per metre: it is in lead time, availability, flexibility and total process cost. For many manufacturers who have been buying seamless tube for years, PRECISE is the most profitable change they can make to their supply chain.
Where the PRECISE range replaces seamless.
Bonnet and boot gas springs · Seat and cab dampers · Sunroof cylinders · Furniture and equipment gas springs.
Precision pneumatic actuators · Low-pressure hydraulic cylinders · Height-adjustment systems · Agricultural machinery cylinders.
Engine cooling circuits · Industrial cooling systems · Low-pressure oil circuits · Heat-exchanger coils.
The perfect bore, in the sectors where the bore is everything.
As specialist manufacturers of high-precision welded steel tube, at Delmàs we develop solutions for the sectors where the tube bore is the critical dimension.
In the mobility sector, the PRECISE range solves applications where the element sliding inside the tube requires the highest bore quality — beyond OPTIM's bead control.
Automotive is the highest-volume sector for the PRECISE range. Low-pressure circuits, gas springs and vehicle interior mechanisms are the most widely deployed applications.
In the home sector, the PRECISE range provides the inner precision that furniture mechanisms, adjustable lighting systems and domestic gas springs need.
Engineering is where the PRECISE range shows its greatest technical differential: it is the direct alternative to seamless extruded tube in all applications where a perfect bore is the determining technical requirement.
We manufacture the part your product needs.
At Delmàs we do not limit ourselves to manufacturing tube. As manufacturers with our own transformation capability, we can deliver a complete solution — from raw material to finished part ready to assemble — with the geometry, dimensions and inner finish your high-precision application requires.
Special profiles
Square, oval or special-geometry tube, maintaining the same PRECISE inner control.
Decorative finishes
Engravings, textures or marks incorporated directly during manufacturing, with no additional operations at the client's plant.
Transformation
Cut-to-exact-length, controlled-radius bending, punching and end tapering for direct piston assembly.
Finished part
From tube to cylinder ready to assemble. We deliver the finished component with mirror bore, ready to receive the piston directly. One single manufacturer controls the entire process.
As manufacturers, our commitment ends when the piston enters the cylinder without friction, noise or play.
Manufacturers who have replaced seamless tube with PRECISE.
The PRECISE range is part of the manufacturing process of companies leading their sectors — manufacturers that depended on seamless tube and that, after validating PRECISE on their lines, have found a technically equivalent solution at a significantly lower cost.
Are you paying the seamless tube price when PRECISE can give you the same at a lower cost?
Let's talk. Send us the diameter, the wall thickness and the application. We will analyse the technical feasibility and, if needed, manufacture samples for final validation in your process.
- Technical response within 24 hours
- Non-standard diameters available (8–25 mm)
- Physical samples in your exact specification