NOVELIS is the leading producer of flat-rolled aluminium products and the world’s largest recycler of aluminium. The company offers highly developed solutions for the aerospace, automotive and beverage can industries, as well as for numerous speciality markets. With seven locations in Germany alone, the site in Nachterstedt plays a central role in supplying global markets with high-quality aluminium rolled products.
It began on 6 August 2019 with an initial visit to the cold rolling mill by EVERTZ HYDROTECHNIK (EHT) and ended in a success story.
Initially, this project was purely aimed at repairing the existing roll cooling system on the CRM4, a SKET Quarto roll stand that was last modernised by Achenbach in 1993. The compressed air-controlled remote system had become outdated and required a great deal of maintenance. Further discussions between NOVELIS and EHT revealed that only the use of a selective ‘state of the art’ cooling system could fulfil the requirements for strip flatness while at the same time reducing maintenance costs. The excellent technical presentation of the spray system and, above all, the very good and long-standing experience that Aluminium Norf had already gained with EHT, especially with its revamps of KW5, KW2 and KW3, were the decisive factors for NOVELIS Nachterstedt to enter deeper into this project with EHT in order to get even more out of its systems.
After analysing the requirements in detail, EHT worked closely with the NOVELIS team and project partner MILLTEC to develop a customised roll cooling system and integrated this into the machine's existing surroundings without any conversion work.
To fulfil the high-quality requirements, the new spray system was equipped with two double-rowed headers for work roll cooling with 26mm/52mm pitch and two single-row spray bars for back-up roll cooling. The extremely compact and modular design of the EHT system enabled efficient integration into the existing infrastructure. Both, the existing connection points in the swivelling device of the upper spray bar and also the supply pipings for the bottom header can continue to be used with the new system.
By using “transformation kits”, identical spray bars could be modelled for the different installation situations top and bottom. This solution offers the customer the valuable flexibility of only having one universal header on stock, which can then be implemented later in a ”roll exchange”. The cable harnesses and the electrical control are designed in such an intelligent way that the spare header can be used if required - regardless of the installation location - without changing the programming or even rewiring.
Fast and precise intervention as part of the flatness control with reaction times in the millisecond range - this is thanks to the EHT COOLECTRO® spray valve, which performs optimally both, in the centre zone with an extremely high flow rate and in the narrow edge zones with 26mm spacing, without any significant pressure drop. The configuration selected by NOVELIS enables the individual control of each nozzle for targeted, selective cooling of the work rolls. The EHT Taylor-Made design ensures optimum positioning of the i-Jet® nozzle in front of the work roll. The reliably reproducible spray jet generated by the patented i-Jet® nozzle offers a good prediction of the spray pattern via simulation.
The spray test carried out in advance on the EHT test area to validate the spray pattern, as well as a 100% in-house functional check of the entire system, were the decisive factors for a timely and smooth “plug and play” commissioning, which was accompanied by EHT in January 2022.
Since then, the system has performed reliably throughout the entire operating time and works maintenance-free and reliably thanks to integrated worst-case filtering!
To assess the condition of the roll cooling system and determine the future NOVELIS maintenance plan for the aforementioned “roll exchange”, EHT carried out the first inspection on 25 May 2023. All nozzles and valves worked perfectly, showed a visually clean spray pattern and responded with excellent behaviour.
After three years of 24/7 operation and millions of reliably executed switching operations of the system, the roll exchange is scheduled to start in 2025 so that the best belt quality can be produced again for three years or more.
Conclusion
The targeted improvements in terms of output and quality were accomplished 100%. All relevant performance parameters were achieved and the FAC was awarded to EHT after just eight weeks of operating experience. The modernisation of the system is clearly noticeable thanks to the increase in productivity and cost savings.
In addition to “first class” technology, the decisive factor for the successful realisation of such a demanding project is the will of the project partners to create something great together and to always react flexibly to changing situations. In keeping with EHT's guiding principle “BOTB - Bring out the best”, NOVELIS was able to rely 100% on this will and the flexibility of EHT.
To quote Thomas Rosenbauer (CEO EHT): “We love short and fast routes, even if challenging decisions, and are only satisfied until the customer is satisfied with us.”
We would like to thank NOVELIS for the trust they have placed in us and look forward to continuing our successful collaboration. With its focus on innovation, quality and sustainability, EHT remains a reliable partner for the aluminium rolling industry.
Outlook / follow-up projects
The next major project with NOVELIS is already underway with the upgrade of the cooling system of the KW4 at Aluminium Norf. In addition, EHT's latest innovation in the field of emulsion and water cooling is currently paving the way - COOLECTRO®PRO!