Up to
35
less volume and weight
Hydraulic cylinders are the heart of every hydraulically driven machine. They move presses, cranes and excavator arms – day after day, millions of times over many years – often under extreme pressure.
Weld seams are usually the weakest points in the design – despite the use of state-of-the-art welding processes, they remain the Achilles heel of every welded hydraulic cylinder. High tensile and compressive alternating loads have a particularly damaging effect on weld seams. Due to local hardening, structural transformations and internal stresses, the material is particularly susceptible to microcracking in these areas. Cracks can grow very quickly and lead to cylinder failure and ultimately to high downtime and repair costs.
The good news is that the deep-R process can be used to mitigate this weak point. ACONA has done pioneering work in the industry and now has a large inventory of deep-R cylinders in the field. Contact us to learn more about validation.
Weld seams as the weak point of hydraulic cylinders
Due to changes in structure, localised increases in stiffness and unfavourable tensile stresses, the weld seam is the weak point in most cylinders.
Added to this is the localised stress concentration or increase in stress that occurs at the root of a weld seam (notch effect). This objectively makes the weld seam the biggest structural weak point. Under continuous stress, inconspicuous cracks spread rapidly and grow over time through the entire cross-section, ultimately leading to sudden oil loss – with collateral damage to the machine, product and personnel.
Unplanned downtime due to defective hydraulic cylinders often causes five- to six-figure costs because press cylinders, hydraulic cylinders for cranes or other machines such as excavators fail completely. This results in additional costs for cleaning, removing oil-related environmental damage and delays in the delivery of spare parts. The total costs are further driven up by new production or hydraulic cylinder repairs.
Why traditional countermeasures do not solve the underlying problem
The obvious approach is often to ‘build thicker’: a thicker weld seam does lead to higher load-bearing capacity, but also to greater wall thicknesses – unfortunately even in places where this is not necessary. In case of doubt, this means several tonnes of additional weight, higher material and energy consumption, additional processing effort and a poorer carbon footprint.
Post-weld heat treatment (PWHT) or stress relief annealing can reduce local unfavourable residual stresses and improve material properties. However, neither of these measures increases the load-bearing capacity of the critical weld root or specifically generates positive compressive residual stresses that counteract the operating stresses. Even with extensive testing and post-processing, the service life of the welded joint therefore remains limited. The safety gain is marginal – the effort involved is high.
X-ray and ultrasonic testing can be used to locate seam defects and minimise risks. However, these methods do not increase the load-bearing capacity itself.
deep-R: Targeted strengthening increases strength where it counts.
With deep-R, we start where conventional hydraulic cylinders reach their limits: directly at the weld seam – the most sensitive point of any cylinder design.
The process, developed in collaboration with leading research institutions, combines state-of-the-art calculation methods with proven strengthening technology. The result: noticeably greater safety, efficiency and service life.
Your advantages at a glance:
increased dynamic load capacity through targeted cold working
Positive compressive residual stresses for maximum fatigue strength
Significant reduction in micro-notches – less cracking, more safety
Service life tests prove: deep-R multiplies the number of tolerable load cycles. The higher fatigue strength enables slimmer wall thicknesses, higher operating pressures and more compact design – without compromising safety.
Measurable effects: longer service life, higher operating pressure and lower volume
To ensure that deep-R's performance is not just impressive on paper, we had the process validated in comprehensive laboratory tests conducted in collaboration with the Machine Tool Laboratory (WZL) at RWTH Aachen University.
After many years, numerous deep-R cylinders are now in continuous use – with great success!
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Up to
25
performance improvement
Up to
100
longer service life
This offers two attractive options for designers and operators:
More power in the same installation space – ideal when higher forces are required,
Same power in a slimmer design – perfect for making machines lighter, more compact and more energy-efficient.
In both scenarios, the total cost of ownership (TCO) is reduced: longer service intervals, reduced downtime risks and lower spare parts and maintenance costs make deep-R a solution that pays off both economically and ecologically, both in terms of purchase and operation.
Conclusion: Why deep-R gives you a real competitive advantage
Our deep-R process specifically strengthens the weld seam – precisely where conventional cylinders reach their limits. Targeted treatment of the seam surface eliminates the weak point. The result: up to 100% longer service life, 25% higher operating pressure and up to 35% less weight and installation space.
Where others reach their limits, we build targeted strength.
So if you need customised hydraulic cylinders for dynamic or highly dynamic, safety-relevant or particularly sustainable applications, deep-R offers you not only a technical innovation, but also an economically and ecologically superior optimisation of your welded construction.
We design individual hydraulic solutions exactly according to your requirements and accompany you from the initial idea to commissioning. All our expertise – design, engineering, manufacturing and our modern machinery – is concentrated at our site in Herzogenrath near Aachen, so you benefit from short distances and quick decisions.
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What can we do for you?Whether hydraulic cylinder enquiry, tube machining, repair or general questions.
We will be happy to advise you.