New secondary cooling patterns for peritectic and microalloyed steel ES leidiniai Leidinio metaduomenys This project is aimed at investigating the surface quality improvement achievable by a fine grain size and small grain boundary precipitate within the surface and sub-surface regions by use of an alternative secondary cooling practice when casting aluminium grain refined and microalloyed peritectic steel grades. A specifically designed intense cooling unit for the intermediate thickness slab Rodyti daugiau caster at Corus Tuscaloosa has allowed optimisation of the operating conditions and an improvement of both as-cast and rolled product surface quality was notes. Limited work tslab 2 0 parinktys an intense secondary cooling was performed for Bloom at Scunthorpe while laboratory and pilot plant studies have demonstrated that an intense secondary cooling to increase the amount of grain boundary ferrite requires a casting speed around 0. CRM has worked on a metallurgical study of the hot ductility improvement achievable by a grain refining treatment and numerical modelling indicates that the feasibility is rather limited as it should combine a quenching to at least °C of 10 mm of the product, a reheating of this outer layer, and a progressive decrease of this layer to reach °C before unbending.
The aim of the project was to improve product quality with two innovative concepts for an optimised heat transfer tslab 2 0 parinktys slab casting of ultra low carbon and peritectic steels.
Rodyti daugiau Industrial trials were carried out aiming at adjusted heat transfer in the mould.
Both concepts were accompanied by physical modelling, numerical modelling with CFD as well as FEM codes and laboratory trials. The industrial trials of the SCPC were prepared by pilot plant trials.
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The LDCC was developed by numerical modelling and tested in an industrial trial. The expected temperature increase in the copper walls was measured but the trials had to be aborted because the mould sealing was damaged.
However, no significant difference to standard production could be proven. Examination of SCPC data measured during pilot plant trials suggested a decrease in heat flux around the meniscus.
Assessment of the pilot plant cast product indicated a significant improvement in surface quality. However, VASL decided after weighting of all arguments not to proceed with an industrial trial.