Ductile iron, known by several names including spheroidal graphite cast iron, spheroidal graphite iron, ductile cast iron, nodular cast iron, or SG iron, exhibits variations in nomenclature across different regions. It represents a graphite-rich form of cast iron, it is typically consisted by 3.2-3.9% carbon, 2.2-2.9% silicon, and 94-97% iron. Compared to gray cast iron, the graphite in ductile iron is nodular or spheroidal in shape, providing it with higher strength and ductility. Unlike conventional cast iron, which often suffers from low tensile strength and brittleness due to the presence of sharp-cornered flake graphite in its microstructure, ductile iron boasts significantly enhanced impact and fatigue resistance. This is attributed to its nodular graphite structure, which effectively mitigates the risk of fracture failure.

Due to its superior performance, ductile iron is widely used across various industries. For example, it is commonly used in the automotive industry for components such as wheels, crankshafts, and steering knuckles, as well as in the manufacturing of industrial equipment such as pipes, valves, and pumps.