engleski

The effects of casting section size and metallic charge materials on microstructure of ductile iron

The influences of different casting section thicknesses (sizes) (6, 3 mm, 12, 7 mm, 25, 4 mm and 38, 1 mm) and the pig iron, steel scrap and ductile iron returns content in metallic charge on the microstructure of ductile iron were analyzed in this paper. It was found that the nodule count, nodularity and pearlite content increases with the decrease of the casting section thickness, due to increase of the cooling rate. As the casting section thickness was increased, the ferrite content and the size of graphite nodules were increased, and the nodule count, nodularity and pearlite content were decreased. The obtained results confirmed the beneficial effect of pig iron addition on the nucleation potential of ductile iron producing an increase of nodule count and nodularity in all casting section sizes. The use of high percentage of steel scrap and ductile iron returns in the metallic charge was resulted in decreasing of nucleation potential, nodule count and nodularity.

ductile iron ; casting section thickness ; metallic charge materials ; microstructure

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