Strategy to increase the hot strip rolling performance in terms of surface quality, final properties and reproducibility

ended

InFire will increase the hot strip rolling performance in terms of final properties, surface quality and reproducibility. High surface quality of hot rolled steel strip and reproducible rolling results are a major challenge today especially for high strength steel grades (AHSS, HSLA) prone to scale related failures and downgrades. Primary scale residues, secondary and tertiary scale formed during the rolling process lead to severe surface impairments and product downgrades while influences and interrelations of the process conditions on final product quality are poorly known. This situation is not acceptable for the new innovative steel grades whose demand is constantly increasing as the hot rolling conditions change while the limits in rolling are not fully known. To improve the understanding of the limits in the process in order to achieve reproducible final properties with main focus on the minimisation of scale related effects on the final surface texture and strip mechanical properties the project Infire was setup by four European steel producer and three research institutes. Conducting various investigations on scale evolution will lead to - description, determination and evaluation of the scale formation and oxide types formed after descaling and during rolling - description of surface phenomena during cooling - evaluation and determination of the interactions in the rolling process including the scale formation mechanisms - understanding and conditioning of scale formation during rolling and cooling, its physical properties, evolution along the hot rolling process and the interdependencies with process liquids. The concentrated approach will lead to an improved control of existing and new actuators, a model for predicting scale behaviour and guidelines for mastering surface defects in order to deliver high yield final products. The increased knowledge will enable existing plants to handle new kind of steel grades in a more efficient and reproducible way.