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.

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 journeyOur Products
Your contacts in Sales

Jörg Schulze
Sales Director Retaining Rings & HNS- Phone: +49 201 17786-3342
- Email: joerg.schulze@gmh-gruppe.de
High-tech and innovation
Top expertise in rotor retaining rings
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

Christian Scholz
Plant Director Energietechnik Essen GmbH | Managing Director- Phone: +49 201 17786-4402
- Email: christian.scholz@gmh-gruppe.de
Downloads
File name | File size | |
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Energietechnik Essen GmbH - Framatome - Standard KTA 1401 with AVS D 100/50, IAEA GSR Part 2, IAEA GS-R-3, IAEA 50-C-Q | 724,60 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 | 202,32 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 | |
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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 | |
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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 | |
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Energietechnik Essen GmbH – General Terms of Sale and Delivery | 129,28 KB | Download |
Your contacts in Human Resources

Martin Karmann
HR Energietechnik Essen GmbH- Phone: +49 2331 128-227
- Email: Karriere.Schmiedag@gmh-gruppe.de
Your contact for Site Communication
Contact

Marlen Thiemig
Communications Energietechnik Essen GmbH- Phone: +49 35263 62 - 627
- Email: Marlen.Thiemig@gmh-gruppe.de