Ductile iron—sometimes called ductile iron, nodular cast iron, ductile iron, or SG (cast) iron—has been an industry favorite since its invention in the 1940s and perfected in the 50s, 60s and beyond. reason? Spheroidal graphite nodules dot its infrastructure, providing structural integrity not found in ordinary cast iron (aka gray iron).
Mechanical Properties of Ductile Iron
Unlike graphite flakes in gray iron, nodular graphite holds ductile iron together without cracking when bent, and acts as a built-in buffer to prevent wear. This results in products with higher ductility, tensile and yield strength, heat dissipation, and vibration and sound damping properties than their gray iron counterparts.
Ductile iron casting process
The higher the number of nodules in a ductile iron casting, the better its strength and elongation properties. We achieved consistently high nodule counts through vertical in-mold inoculation. In this method, the molten metal is inoculated with magnesium as it is poured into each mold, ensuring even distribution within and between the molds. Our proprietary vertical casting process minimizes air pockets and other structural defects while consistently maintaining a nodularity rate of 85% or higher—far exceeding industry standards.
Benefits of Ductile Iron Castings
Ductile iron offers flexibility in both its physical properties and design. Its castability, machinability, elongation and deformation without breaking ability are far superior to gray cast iron.
The price of ductile iron is significantly lower than that of cast steel, and only slightly higher than that of gray cast iron. However, its overall performance and wear resistance make it a cost-effective solution.
Ductile iron is a very elastic material in terms of yield strength and tensile strength, meaning it can withstand enormous physical stress without changing shape or breaking.