Ductile Iron Specification

What is Ductile iron?

Ductile iron, also known as ductile cast iron, nodular cast iron, While most varieties of cast iron are weak in tension and brittle, ductile iron has much more impact and fatigue resistance, due to its nodular graphite inclusions.

Ductile Iron Casting grades and mechanical properties of single cast styles

Composition

• Iron ~94%
• Carbon 3.2 – 3.60%
• Silicon 2.2 – 2.8%
• Manganese 0.1 – 0.2%
• Magnesium 0.03 – 0.04%
• Phosphorus 0.005 – 0.04%
• Sulfur 0.005 – 0.02%
• Copper <= 0.40%

To improve the strength of ductile iron, additional tin or copper can be added.  To improve corrosion resistance, copper, nickel, or chromium can replace anywhere from 15-30% of the iron.

Benefits of Ductile Iron Casting:

• It has superior castability and machinability.
• It has an excellent strength to weight ratio.
• Cost of ductile iron casting is lower than steel castings.
• Compared to grey iron casting, ductile iron has much more impact and fatigue resistance, due to its nodular graphite inclusions.
• Ductile iron casting provides a designer with an exceptional combination of toughness, low cost manufacturing, and reliability.