Precision welded steel tube for fluid circuits: the same performance as seamless, at a fraction of its cost.
Same circuit. Same leak-tightness. Different tube. Different cost.
Cooling circuits, low-pressure fluid management systems and engine oil lines have historically used seamless extruded tube — not because it is the only technical option, but because historically it was the only known one. That fear has a name: the weld might leak. And that fear has a real cost: seamless tube is between 30% and 80% more expensive, scarce and with unpredictable lead times.
Delmàs precision welded tube — PRECISE range for larger diameters and higher inner precision requirements, PREMIUM or OPTIM for smaller diameters or low-pressure leak-tightness applications — meets the leak-tightness and pressure requirements of these applications at a significantly lower cost and with immediate availability.
The welding Delmàs uses is not the welding of the 1960s. It is a high-precision Electric Resistance Welding (ERW) process, certified on every batch, with weld quality control on every metre of tube produced. It is not a weak point. It is a controlled process that certifies its integrity with every delivery.
For manufacturers who have been buying seamless tube for their fluid circuits out of habit, switching to Delmàs precision welded tube is probably the most profitable change they can make to their supply chain — without changing anything in their manufacturing process, valves, fittings or connectors.
"Same circuit. Same leak-tightness. Different tube. Different cost."
The seamless argument made sense. Forty years ago.
Seamless extruded tube has a real advantage: there is no inner weld bead that could be a potential leak initiation point. In the years when welding technology could not guarantee consistent joint quality, that argument was valid. Today, with the high-precision ERW technology Delmàs uses, that argument no longer stands technically.
What does remain is the cost: seamless tube is between 30% and 80% more expensive depending on diameter and market. And the lead times: in diameters outside the standard catalogue, lead times are very uncertain and unpredictable. And availability: in small diameters under 25 mm, scarcity is even greater.
The real cost
Extruded tube costs between 30% and 80% more than the equivalent precision welded tube depending on diameter and market. At high volumes, that difference accumulates every month.
Technically equivalent leak-tightness to seamless. Precision welded tube pricing.
The real lead time
Seamless tube in diameters outside the standard catalogue has very uncertain and unpredictable lead times. In small diameters (under 25 mm), scarcity is even greater.
Predictable availability in weeks. Diameters 3–25 mm including non-standard sizes on request.
The real availability
In non-standard diameters — exactly those that many applications require — seamless tube is simply unavailable or involves unworkable MOQs.
Custom manufacturing in 3–25 mm. Flexible orders. First trial order possible without punishing MOQs.
Where it is applied: all sectors with low-pressure fluid systems
Low-pressure fluid management is one of the most versatile applications in the Delmàs catalogue. The exact range depends on the diameter and the level of inner precision required: PRECISE for the highest inner precision applications, PREMIUM or OPTIM for small diameters and low pressure.
Engine cooling circuits, air conditioning systems and oil lines have used seamless tube historically because of fears that ERW welding would create weak points. That fear has an annual accumulated cost that nobody has quantified.
Industrial fluid circuits, machinery cooling systems and process oil lines have used seamless tube out of habit. In low and medium-pressure applications where a mirror-quality inner bore is not required, the cost of seamless is not justified.
Hot water circuits, heating systems and refrigerant lines in premium domestic appliances use small-diameter tube where leak-tightness is critical but production volume justifies switching from seamless to precision welded tube.
The right range depends on the diameter and on the inner precision requirement
For: higher pressure circuits, precision inner bore.
- Mirror bore
- OD 8–25 mm · Wall 0.5–8 mm
- EN 10305-2 · ASTM 513 T5/T6 · JIS G3445
- Replaces seamless
For: fluids where the ID is relevant.
- Bead ≤ 0.15 mm
- OD 3–10 mm · OD+ID control
- EN 10305-3/2 · SAE J356
- Inner diameter defined with client
For: low pressure, small diameters.
- Bright surface
- OD 3–13 mm · Wall 0.4–2.0 mm
- EN 10305-3 · ASTM 513 T2/T4 · SAE J526
- Chrome-ready
The question is not whether precision welded tube can replace seamless in fluid applications — it already does in hundreds of applications. The question is how much continuing to use seamless is costing when it is no longer necessary.
This application is present across every sector with low-pressure fluid circuits
Are you still paying the seamless tube price for your fluid circuits? Send us the problem and we will design the solution together.
- Technical response within 24 h
- Physical sample available
- Product certificate on every batch