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Ductile Iron Casting: Process, Composition & Advantages

Iron-carbon alloy tweaked by adding magnesium or cerium is what is commonly known as ductile cast iron. Ductile cast iron reacts with sulfur and oxygen while the iron is in the molten stage to create a more ductile alloy.

Cast iron is more of a brittle alloy as compared to ductile cast iron. Little addition of magnesium or cerium allows the ductile cast iron to have a stable alloy structure. The Resulting solidified castings have almost perfect nodules of graphite in it. Ductile cast iron is known for high resistance against impact and fatigue.

How Is The Ductile Cast Iron Made?

Similarly, like any cast iron, ductile cast iron gets its magic from being inside the furnace. The process revolves around incorporating more carbon into the molten iron. The iron in the molten state gets the magic potion of silicon, sulfur, manganese, and oxygen.
This oversimplification of the process might make it look easy but is not this simple in reality. The prime part of the process is adding carbon to iron as much as it can absorb. The composition mix gives the alloy the infamous spherical structure of graphite.

Ductile Iron Advantages

Ductile Iron Casting made out of ductile iron are significantly solid than regular grey iron or cast iron. Tensile strength of grey iron form stands between 20000-60000 psi. However, ductile cast iron can endure as much as double-cast iron’s highest psi strength.

Here are some more advantages –

  1. Ductile cast iron is a more potent form of cast iron. Unlike cast iron that can break easily, ductile cast iron can endure much more.
  2. Nodule formation in ductile cast iron promotes it to bend and not break, unlike the cast iron.
  3. Graphite structure of ductile cast iron works as a dry lubricant to have excellent wear resistance.
  4. Even after being harder to work with than cast iron, ductile cast iron dissipates and dampens vibration, sound, and heat.

Ductile Cast Iron Uses And Application

The ductile cast iron can offer strength, and enhanced wear resistance makes it fit for various uses. Here are some items made from ductile cast iron:

  • Pipe and its fittings
  • Axles
  • Cylinders
  • Crankshafts
  • Disc-brake Calipers
  • Gears
  • Gear Boxes
  • Housing
  • Hydrostatic Barrels
  • Idler’s Arms
  • Large Machinery
  • Military works
  • Piano Harps
  • Spindle support
  • Suspension parts 
  • Truck Axles
  • Valves for high pressure
  • Wheel Hubs
  • Power Transmission Yokes

Difference Between Regular Cast Iron And Ductile Cast Iron

Cast iron is easier and cheaper to cast, and strength is possible with heat treatment. Cast iron has a flakes structure of graphite. On the other hand, ductile cast iron offers higher strength and durability due to the graphite sphere structure.


Ductile iron has the upper hand at durability, given the spherical structure of graphite. Cast iron or grey iron is cheaper but lacks the wear resistance that improves the uses. The most popular type to be used for industrial purposes is the ductile form of cast iron. To know more about the best ductile iron casting manufacturers in India, you can follow