Estudo das var iações na microestrutura , na composição química e nas propriedades mecânicas de cubos de roda em ferro fundido nodular perlítico submetido a diferentes materiais inoculantes.

Abstract

The objective of this work was to analyze the effe ct on microstructural characteristics, chemical composition and mechanical properties as a function of the application of different inoculation processes and of different inoculating materials on wheel hubs manufactured in nodular cas t iron of perlite matr ix, observed for the same times and temperatures of leakage. The samples were submitted to In Mold inoculation (in the mold itself) and inoculation in the jet (at the time of casting) using three different types of iron silicon base i noculants: 75% Fe Si c ontaining calcium and barium ( Fe Si Ca Ba 75%), and two industrial inoculants containing in their composition silicon, magnesium, aluminum and calcium in different proportions, denominated, for this work, of tablet A and tablet B. In order to evaluate the e ffects of the different inoculant materials on the mechanical properties of the nodular cast iron of perlite matrix, hardness tests and traction tests. After the tests, it was possible to observe the hardness variations, in addition to obtaining the values of elongation, flow and tensile strength of each sample. To evaluate the microstructural effects of the samples, metallography and optical microscope analysis were performed to deter mine the graphite nodule count, the phase count and to determine the ty pe and size of the nodular graphite formed. In order to evaluate the effects on the chemical composition, analyzes were performed on optical emission spectrometers, through the burning of specimens taken from the samples . It was ver ified that the samples inoculate d with the three different inoculant materials presented chemical composition, mechanical properties and microstructural characteristics suitable for the manufacture of perlite nodular cast irons. It was also verified that t he samples inoculated with the i noculant in tablet A presented higher number of nodules per mm², better mechanical properties and smaller deviation between the results obtained for each sample.