A STUDY ON RELATIONSHIP BETWEEN CASTING GEOMETRIC MODULUS AND FEEDING DISTANCE OF DUCTILE IRON BAR-SHAPED CASTINGS

摘要

Ductile iron is an engineering material gaining its popularity for its versatility in making complex engineered components. Ductile iron, also known as nodular iron or SG iron, has graphite in the form of spheroids. The solidification phenomena of ductile iron are complex since it has long freezing range and the formation of thin flexible skin where the metal comes in contact with the mold or core. Ductile iron microstructure is more sensitive to solidification due to the presence of magnesium which influences the thermo-physical properties of the material such as surface tension, viscosity and thermal conductivity. Formation of non-metallic oxides, silicates and sulfides during nodularization treatment makes solidification more complex. Various attempts have been made to understand the effect of solidification behavior on the feeding distance. Very little work has been done on the feeding distance of ductile iron casting shapes. In this paper, an attempt is made by conducting series of experiments to find out the maximum feeding distance in the bar-shaped ductile iron sand castings as a function of the geometric modulus.