This diploma work covers the test of various inoculants designed for achieving sufficient amount of graphite particles in cast iron. Through a centrifugal casting process, three commercially available iron and silicon-based inoculants were tested on a special carbide enhanced cast iron. All experiments were carried out on an industrial level in the company Valji d.o.o.
The aim of the diploma work was to select the most suitable inoculant, that will be further used to achieve graphite in the working layer of indefinite chill rolls.
The first part includes a description of the modern production process of cast rolls for hot strip rolling, the role of work rolls made of indefinite cast iron as rolls for the final frames of continuous rolling mills. The role, purpose, and achievement of graphite in the working layer of these rolls are described. As part of the experimental work, from a group of six, three inoculants were selected, which were added to the melt stream during the discharge from the furnace. The melt was then cast into a steel mold using a horizontal centrifugal machine. Nodular grey cast iron was used for the roll core. For the purposes of this diploma work, samples were cut out of the rolls, from which the entire profile of the working layer was visible. In the analysis of the samples, the proportion and shape of the participated graphite were observed using optical microscopy and computer software. The hardness drop along the working layer profile was also measured separately. Based on the results of the analysis, the most appropriate inoculant was selected.
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