Redução do consumo de ferro-ligas utilizadas no refino secundário via forno-panela de uma aciaria elétrica

Abstract

With the evolution of steelmaking processes , great advances have been achi eved in all st ages of ste elmaking, one of the main ones is secondary metallurgy, which can b e defined as metallurgical work to adjust the ch emical composition and temperature carried out outside the primary furnace of fusion. In the first place, it is know n that both ac tions carri ed out in the primary refining stage as well as in the secondary r e fi ning stage will have a direct effect on the ch emical composition of the steel to be manufactured. Thus, directly or indirectly, suc hactions will affect a set of properties of the steels. Therefore, it is necessary to have a better knowledge about the e f fe ct of the alloying and residual elements on th e properties of the steels, since over time the demands on the refining processes hav e been increasing significantly , consequently becoming e ssential for the competitiveness of a power plant to be able to co n tr ol more and more accurately the elements gener ally present in steel. In this way, this work intends to contribute with a study dire cted to the reduction of the co nsumption of t he main fer roalloys used in the secondary refining stage through the ladle fu r na ce, ferro silico manganese and ferrosilicon 75 , and graphite fuel to evaluate the consequences on the mechanical properties, to ana lyze the possible gains and to identify the b est additio ns standard that meets the metallurgical characteristics of the fi n al product. The study presents the construction of statistical analyses, such as control charts, normality tests, and capacity or cap ability analysis, to verify the influence of the new rec ipes on the properties of: yield limit, tensile strength limit and el ongation; in the main products manufactured by a mini mill, that is, rebars or ribbed bars for civil construction. After this, test s were performed for the narrow ing of bands o f chemical composition, implementing a mass balance via a spreadsheet with SO L VE R extension for prediction calculations of the ideal addition of ferroalloys and fuels, performing a mean displacement for SAE 1017 steel and concluding with comp arisons betwee n the resul ts obtained and the results of the revenue previously used in the p ro cess. In that it was proven that such displace men t did not alter the main properties of the final product, that is, the objective was achieved.