Avaliação do comportamento das inclusões não metálicas de um aço peritético durante as etapas finais de refino

Abstract

The present work is based on the characterization of non-metallic inclusions of a perithetic steel in the final stages of refining. The control of the types of inclusions is very important to achieve properties such as improved machinability, good mechanical properties and absence of cracks. The steel sampling took place in the following stages of the process: beginning of the ladle furnance, after final adjustment of chemical composition in the ladle furnance, tundish and slab. The steel samples were prepared metallographically without the need for etching. An area of 25 mm² was selected and analyzed by scanning electron microscope equipped with an EDS detector. Thus, if the inclusion quantities were obtained by area analyzed, the size ranges of the inclusions and their compositions, in observing them, the difference in the amount of inclusions between the analyzed samples could be discussed. A plot them were done in ternary diagrams, observing their respective melting points and thus know the amount of solid and liquid inclusions at the steelmaking temperatures.