Effect of Sulfur on the Formation of the Graphite Degradation in Ductile Iron

The objective of this study is to evaluate the effect of sulfur in core sand on the formation of the graphite degradation in ductile iron. The graphite degradation is caused by the depletion of Mg in liquid iron resulting in low nodularity zone underneath the casting surface. The content of sulfur in molding materials has been known as an important factor of the occurrence of the graphite degradation. It was found that the greater content of sulfur in the core sand promoted the formation of the graphite degradation. The graphite degradation with the thickness ranged from 113 to 1116 μm was observed for the sulfur content from 0.24 to 1.68 wt%S.