Rolling is the process of forming substances such as metals into shapes that are small in comparison with their length. Examples of rolling end products include bars, sheets, rods and rails. Rolling may be done while the steel is hot, a process known as hot-rolling. However, when cycling between hot and cooled conditions, the roll surface where the steel is pressed can deteriorate. To deliver optimal performance, ways to best preserve the original roll surface were much needed.
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Started in July 2004, the Effective Work Roll COOLing (EWRCOOL) was a project under the Research Fund for Coal and Steel (RFCS). For 42 months, it aimed at finding new and improved hot rolling processes. Specifically, EWRCOOL gained valuable knowledge of roll cooling systems in long product steel mills.
With European Union (EU) funding of €1.15 million, EWRCOOL was coordinated by Tata Steel in the United Kingdom and had several partners from Italy, Spain, Germany, Czech Republic, Belgium and the UK.
Significant improvement in roll cooling technology knowledge was achieved during the lifetime of EWRCOOL. The design of roll cooling for long product mills has been accentuated through enhanced knowledge of roll cooling methods, components and system design. The project has also enabled long product mills to use high-alloy steel rolls which was previously only possible in flat product mills.
"The roll materials and technologies used in long product mills have traditionally lagged far behind those used in flat product mills, primarily because of the complexity of cooling systems required for rolls that have curved and shaped surfaces," says project coordinator Andy Heeley of Tata Steel. "Understanding how to improve roll cooling system design and how to tailor it to long product rolls has been crucial for the development and use of advanced roll materials and cooling methods."
Results under EWRCOOL are impressive. For example, it is estimated that raw materials savings amount to approximately €5 million each year. In addition, a yearly reduction of €225,000 in roll losses has been reported by one mill adopting improvements to roll cooling. Finally, the project has seen an estimated €500,000 reduction in water use.
EWRCOOL has also resulted in the roll cooling process having a lower impact on the environment due to reduced water and chemicals required as well as lower energy consumption. According to Heeley, there are other intangible benefits including the increased level of knowledge acquired and higher levels of productivity.
Results of EWRCOOL appeared in 8 journal and conference papers that targeted the wider scientific and engineering community. In addition, a one-day technical seminar was organised at Brno University of Technology that served the purpose of sharing experiences of roll cooling system developments at long product mills.
EWRCOOL has certainly set the scene for better cooling systems and advanced roll materials. According to Heeley, the project has laid the foundations for the RFCS Pilot and Demonstration project known as 'Selective Roll Cooling' as well as the RFCS Research project 'LPRollCoat'.