Welcome to
Energietechnik Essen GmbH!

Energietechnik Essen GmbH is the global specialist in rotor retaining rings for energy-sector machinery and a byword for safety and reliability in turbo-generators. The company also develops and produces nitrogen-alloyed steels.

Plan your journey

Your contacts in Sales

Jörg Schulze

Sales Director Retaining Rings & HNS

High-tech and innovation

Top expertise in rotor retaining rings

No one in the world can match our more than 100 years of experience in the production of rotor retaining rings - precision components that reliably withstand the centrifugal forces encountered in today's increasingly powerful generators, where the rotors regularly reach speeds of up to 3,600 rpm.

Specialist in extreme applications

Our CRONIDUR® 30 cold-working steels incorporate a unique combination of properties. In many cases, they are what make innovative, highly stressed applications in aerospace, mechanical engineering, medical, pharmaceutical and foodstuffs technology, and also in the production of high-quality consumer goods, at all possible.

Steel that delivers safety

Our precision-engineered special steels are in demand around the globe: for satellites hurtling through space, for Formula 1 race cars performing to their limits on the world's top circuits, in beverage filling plants and for the springs that give high-end watches their extreme timekeeping accuracy. These steels assure product resilience and are the driving force behind whole industries.

Our production facilities

Two remelting furnaces

We use a standard electroslag remelting furnace and a pressure electroslag remelting furnace to produce the materials needed for retaining rings, and also for numerous other high-nitrogen austenitic and martensitic special steels in a wide range of dimensions and for the most diverse applications. These two installations produce remelt ingots with weights extending from 1 to 30 tonnes and diameters from 400 to 1,000 mm.

Expanding press of approx. 2,300 millimeters

We use an expanding press that exerts a force of 60 MN for cold expansion of our retaining rings. This enables us to achieve diameters of up to 2,200 mm and height of up to 1,480 mm. Cold expansion is a special variant of strain hardening that assures the precise attainment of the specified ultimate mechanical strength in the P900 austenitic material used for this application.

Machining/ incl. wage work

Our retaining rings are turned on seventeen carousel lathes. Maximum item weight 16 tonnes, maximum diameter 3,070 mm. A centre lathe, band saws and other mechanised cutting equipment complete the machining facilities at Energietechnik Essen GmbH and extend the range of operations we can perform.

Heat treatment/ incl. wage work

Systematic heat treatment enables us to meet precisely our customers' requirements for optimum hardness and toughness of steel - soft and solution annealing, normalising, oil and/or water quenching and tempering.

Site management

Nicolas Kardalo

Plant Director Energietechnik Essen GmbH | Managing Director


File name File size
Energietechnik Essen GmbH - Framatome - Standard KTA 1401 with AVS D 100/50, IAEA GSR Part 2, IAEA GS-R-3, IAEA 50-C-Q 491,01 KB Download
Energietechnik Essen GmbH - TÜV NORD - AD 2000-Merkblatt W0 442,17 KB Download
Energietechnik Essen GmbH - TÜV NORD - KTA 3201.1, Item 2.4 312,58 KB Download
Energietechnik Essen GmbH - TÜV NORD - QAS for material manufacturer according to directive 2014/68/EU 436,68 KB Download
File name File size
Energietechnik Essen GmbH - Certificate of Compliance Cronidur 30 1,18 MB Download
Energietechnik Essen GmbH - DNV - ISO 14001 202,65 KB Download
Energietechnik Essen GmbH - DNV - ISO 45001 205,40 KB Download
Energietechnik Essen GmbH - DNV - ISO 50001 205,37 KB Download
Energietechnik Essen GmbH - DNV - ISO 9001 203,12 KB Download
File name File size
Energietechnik Essen GmbH - Cronidur® 30 176,81 KB Download
Energietechnik Essen GmbH – Cronidur® 30 – EN/CHIN 252,03 KB Download
Energietechnik Essen GmbH – Cronidur® 30 – FRZ 108,54 KB Download
Energietechnik Essen GmbH – Cronidur® 30 – RU 215,36 KB Download
Energietechnik Essen GmbH – P2000 318,16 KB Download
File name File size
Energietechnik Essen GmbH – General Terms of Sale and Delivery 129,28 KB Download

Careers at GMH Gruppe

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Our values

For us at GMH Gruppe, responsibility, team spirit, transparency and trust are not just empty words, they are values that are lived out every day by our employees.

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Available apprenticeships/traineeships

Your contacts in Human Resources

Martin Karmann

HR Energietechnik Essen GmbH

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Marlen Thiemig

Communications Energietechnik Essen GmbH