Success with U

Case Studies Call ETU

Introducing U: Case Studies & References

Getting to know one another only works if we open up. That’s why we’re opening our doors to you. Here’s how some of our most exciting projects unfolded:

Exceptional U: High performance in extreme lengths

Extraordinary dimensions call for extraordinary solutions.

In this case, we took on a large-scale contract bending job – quite literally:

4,706 cold-bent, low-finned U-tubes
made from TP 439 with unusually long legs of up to 17,273 mm
plus insert tubes of up to 35,589 mm

In addition to the precision machining, it was above all the extreme lengths that posed a logistical and technical challenge – from in-house handling to transport and packaging, right through to quality assurance and acceptance.

A production project on this scale had never before been carried out in Germany.

U-Rohr in Überlänge auf LKW vor unseren Werkhallen

Coming together for U

An interdisciplinary project team comprising members from production, the order centre, quality assurance, the customer and the logistics partner developed a tailored solution for each individual challenge.

These included, amongst other things, adapting the production facilities to the extreme lengths, detailed scheduling and staff planning, as well as specially developed transport and packaging concepts. Throughout, we kept sustainability in focus, whether in terms of transport emissions or energy efficiency in production.

Close coordination between all parties involved ensured that, despite the large volume of material, day-to-day operations at ETU were not disrupted.

Rohre in Überlänge auf LKW in unseren Hallen

Win-Win with U

Thanks to close collaboration and technical precision, the project was carried out entirely in Germany – a production process that would not have been possible without the solutions we developed.

The result: 4,706 flawlessly bent U-tubes, securely packed in 36 wooden crates and delivered on time. This created a genuine win-win situation for both our customer and ETU itself: maximum quality, secure supply chains and strong evidence that complex tube projects can also be carried out efficiently within Germany.

U-Rohre in Überlänge sicher und geschützt verpackt

Two Sides of U: One tube, two materials

When two materials present completely different challenges, solutions are needed that think one step ahead.

For this project, we undertook the manufacture of

352 U-tubes
in 180° and box-shaped (2×90°) configurations
based on 25.0 × 1.50 mm tubes
made from grade 1.4404
externally coated with 0.40 mm film

The particular challenge:

Bending and sawing the tubes without causing even the slightest damage to the delicate coating. Technologically, this meant simultaneously machining two completely different materials – metal and coating – to extremely tight tolerances.

U-Rohre mit Beschichtung, beschädigungsfrei gebogen trotz zwei verschiedener Werkstoffe mit unterschiedlichen Ansprüchen

Engineering for U

The solution was developed in close consultation between production, the order centre, quality management and the customer.

To protect the coating throughout the entire machining process, our machines were specifically adapted. Standard tools weren’t enough:
New bending tools were designed, manufactured and tested, supplemented by specially developed protective mechanisms that enabled damage-free bending and sawing.

Quality assurance was carried out in collaboration with the customer. Each individual tube was subsequently subjected to a high-voltage test to verify the complete integrity of the coating – a testing procedure that ensures maximum safety.

Realising U – without compromise

Without the technical solutions developed, it would not have been possible to manufacture these tubes.

The result:
352 flawless U-tubes, fully inspected – with the coating undamaged and the tubes carefully packaged to ensure safe transport.

This delivered significant added value for the customer: direct oversight during production, 100% first-pass yield, streamlined coordination processes and a reliable partner for the implementation of a specialised heat exchanger project.

Beschichtete U-Rohre in besonderer Verpackung für Schutz und Stabilität

Maximum Security for U: The Core of Power

Since 2019, we have regularly manufactured heat exchangers for French nuclear power stations. These heat exchangers are used exclusively in the event of an incident. Their role is to maintain cooling as an additional safety circuit – a key element in preventing major disasters.

The background to this dates back to the Fukushima nuclear disaster in 2011. In the wake of this, existing plants across Europe were retrofitted with additional safety systems. As a long-standing and trusted partner, we were chosen to reliably carry out these highly sensitive projects.

Naturally, sustainability plays a central role here: in the event of an accident, the additional cooling circuit specifically prevents far-reaching consequences for the plant and the people working there.

However, our commitment to sustainability goes far beyond this: it extends to numerous efforts to minimise unnecessary material waste and emissions, while placing great emphasis on the choice of packaging and short supply chains.

We manufacture approximately 500 U-tubes per heat exchanger. Between 2019 and 2025, 26 complete heat exchangers were built – further projects are currently underway.

U-Rohre für Wärmetauscher für französische Atomkraftwerke

Strict Rules for U

The greatest challenge lies not in any single production step, but in the consistent adherence to and ongoing tightening of nuclear requirements.

Every heat exchanger is subject to recurring acceptance inspections, during which strict compliance with all guidelines, customer specifications and additional special requirements is verified:

Packaging: The tubes are stacked in layers, separated by plastic film inserted horizontally, so that no two tubes touch. The effort involved is significantly greater than the industrial standard, but is absolutely essential.
Documentation requirements: Extensive dimensional checks are carried out, clearly assigned to individual straight tubes and documented in special forms.
Mandatory qualification process: Completed before series production begins, it is binding for all subsequent processes. Deviations in series production are not permitted.
Minimum permissible wall thickness: At 0.99 mm in the tube bend, the minimum wall thickness is close to the technical limit of feasibility, given the agreed ‘average wall’ specification for the straight tube. Targeted additional measures ensure flawless results: the use of tubes with increased wall thickness, meticulous alignment of the straight tubes, and measurements before and after bending.
Material requirements: Any material coming into contact with the tubes must be known in all components or approved in accordance with PMUC (EDF). The proportion of critical elements such as halides or sulphur is strictly limited.
Maximum safety: All support and contact surfaces are covered with PMUC-approved VCI or ICB film to ensure that only permitted materials with a known composition come into contact with the tubes throughout the entire manufacturing process.

U-Rohre für Kernkraftwerke in besonders geschützter Verpackung

Complete Trust in U

The project is carried out with particular care in terms of handling, transport and dimensional checks. Short lines of communication between production and administration enable rapid coordination and the direct implementation of new specifications.

The fact that the project has been ongoing for years and that further heat exchangers have already been ordered speaks for itself: consistent quality, efficient processes and a high level of trust.

For the customer, this means working with an experienced, well-coordinated team, minimal staff turnover and the assurance that even the most complex nuclear requirements will be reliably met. Ideally, of course, the product will never be needed during trouble-free power station operation.

U-Rohre für Wärmetauscher für ein Kernkraftwerk, sicher verpackt

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