Examination of the factors affecting quality on continuous annealing processing lines

The Continuous Annealing Processing Line (CAPL) of the Corus Strip Products UK integrated works in South Wales, United Kingdom, is one of the most modern lines of its type in the world. It produces thin and wide carbon strip steels of the highest quality in terms of metallurgical consistency, surfac...

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Bibliographic Details
Main Author: Saunders, Paul
Published: Swansea University 2008
Online Access:https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.752120
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Summary:The Continuous Annealing Processing Line (CAPL) of the Corus Strip Products UK integrated works in South Wales, United Kingdom, is one of the most modern lines of its type in the world. It produces thin and wide carbon strip steels of the highest quality in terms of metallurgical consistency, surface quality and dimensional tolerances. Tensioned strip can travel at a velocity of up to 600m/min at temperatures in excess of 750°C. The yield point of the strip is naturally reduced at these annealing temperatures; therefore the contact interaction that develops between the transport roll and the strip steel it is transporting is critical. The primary focus of research is on maintaining the elasticity of the strip steel as it passes through the furnace section of the continuous annealing processing line. In particular focusing on the heating and adjacent soaking sections of the CAPL, where the temperatures are at their highest. The thesis is concerned with the roll-strip interaction and its many different parameters - roll geometry, strip dimensions, strip tension and strip temperature. Research concentrated on the initial contact plane, where the strip first comes into contact with the transport roll. Results indicate that the strip's elastic stress- state is most affected by the fillet that circumnavigates the transport roll, especially where the fillet intersects the initial contact plane. The parameters chosen took into consideration the future operational commitments of the CAPL, because continual demand is always increasing the threshold. To perform the task assigned the author made use of extensive computational finite element method models. A second aspect of the research was to consider acceptable temperature differentials between the transport roll and the strip steel at initial contact. The strip has a low yield stress at its annealing temperature, thus an excessively high temperature differential will create a buckle risk. Therefore, an experimental programme was developed in conjunction with industrial partners Stein Heurtey to investigate acceptable temperature differentials for initial contact conditions.