ESTUDO DA MORFOLOGIA, TAMANHO, DISTRIBUIÇÃO E PRECIPITAÇÃO SOBRE ÓXIDOS DE INCLUSÕES DE SULFETOS DE MANGANÊS EM AÇOS RESSULFURADOS
STUDY OF MORPHOLOGY, SIZE, DISTRIBUTION AND PRECIPITATION ON OXIDES OF INCLUSIONS OF MANGANESE IN RESULPHURISED STEELS
Alexsandro Bobsin, Wagner Viana Bielefeldt, Antônio Cezar Faria Vilela
Resumo
O enxofre tem influência direta nas propriedades mecânicas nas diversas classes de aços, principalmente se formar FeS que reduz a resistência no trabalho a quente, devido ao seu baixo ponto fusão. A fim de que o teor de enxofre seja controlado na produção do aço, tem sido aplicada a adição de elementos de liga como o manganês. O manganês reduz consideravelmente a solubilidade do enxofre pela formação de sulfetos de manganês com a redução da temperatura. Estas inclusões controlam o crescimento do grão e facilitam a usinagem, aumentando a vida útil das ferramentas de corte. No entanto, prejudicam a qualidade dos aços e provocam problemas como redução na dutilidade e qualidade superficial de chapas laminadas a quente. Portanto, este trabalho fará uma abordagem sobre as influencias de processos, objetivando estudar sua morfologia, distribuição e tamanho médio, assim como, a precipitação dos sulfetos de manganês sobre óxidos; usando análise de imagens produzidas a partir de amostras retiradas de aço ressulfurado.
Palavras-chave
Abstract
Sulfur has a direct influence on the mechanical properties of the various grades of steel, especially if it forms FeS, which reduces the resistance to hot rolling due to its low melting point. In order that the sulfur content is controlled in the production of steel, the addition of alloying elements such as manganese has been applied. Manganese considerably reduces the solubility of sulfur by the formation of manganese sulphides with the reduction of temperature. These inclusions control grain growth and facilitate machining, increasing the life of cutting tools. However, they impair the quality of the steels and cause problems such as reduction in the ductility and surface quality of hot-rolled sheets. Therefore, this work will focus on the influences of processes, aiming to study their morphology, distribution and average size, as well as the precipitation of manganese sulphides on oxides; using image analysis produced from samples taken from resulphurised steel.
Keywords
Referências
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