Influence of Secondary Introduction of Carbon and Ferrosilicon on the Microstructure of Rotary Furnace Produced Ductile Iron

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Author(s) Alasoluyi. J.O | Omotoyinbo J. A. | Borode J. O. | Olusunle S.O.O. | Adewoye O.O.
Pages 211-217
Volume 2
Issue 2
Date February, 2013
Keywords Ductile Iron, Inoculants, Microstructure
Abstract

The production of various grades of ductile cast iron using carbon from graphite, ferrosilicon and its mix as inoculants has been achieved using a rotary furnace. Powdered graphite, ferrosilicon and graphite with ferrosilicon mix were used separately as inoculants on magnesium treated cast iron melt. 680g of magnesium ferrosilicon was used to treat 40kg mass of molten metal in ladle by sandwich process and poured into sand mould where it was inoculated with 72g of powdered graphite and ferrosilicon respectively to produce 30kg ductile iron casting. Similarly, 36g and 18g each of powdered graphite mixed with ferrosilicon (ratio 1:1) were used separately as inoculant to study the synergistic effect of these materials on the final microstructure of the ductile iron produced. Increasing graphite in the ductile iron promotes pearlite formation in the matrix of the graphite nodules while increase in ferrosilicon addition considerably gave rise to ferritic matrix of the graphite nodule. Also the synergistic effect of the graphite and ferrosilicon additions as inoculants progressively influenced the microstructure of the ductile irons produced. The graphite nodules obtained in the final ductile iron castings from the inoculations showed the bull’s eye structure in the pearlitic and pearlitic-ferritic matrices. This procedure can therefore be used to predetermine types of matrices in ductile iron.

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