Ductile Cast Iron Castings

Ductile iron refers to cast iron in which the graphite is spherical after the molten iron is treated with a spheroidizing agent. That is why the ductile cast iron is also called spheroidal graphite cast iron or nodular cast iron. Inside the ductile cast iron by electron microsope, the shape of spheroidal graphite is approximately spherical, and its interior is radial shape, and it has obvious polarization effect. The spheroidization rate refers to the percentage of the total number of spherical graphite in a certain range to the total number of graphite. The spheroidization rate is an index to measure the spheroidization grade of nodular cast iron, and it is an important standard in ductile cast iron castings.

Performance Characteristics of Ductile Iron Castings

• Fluidity and line shrinkage of ductile iron are very close to those of gray cast iron
• The tendency of volume shrinkage and internal stress formation is greater than that of gray cast iron, which is prone to shrinkage and cracks
• The strength, plasticity, and elastic modulus of ductile iron are larger than those of gray cast iron, with good abrasion resistance
• Shock absorption is worse than gray cast iron

Structural Characteristics of Ductile Iron Castings

• Generally designed to be uniform wall thickness, and try thick section should be avoid if possible
• For certain thick and large section castings, hollow structure or structure with reinforced ribs should be adopted