Last updated: September 16, 2020

Nodular cast iron is produced by adding magnesium to the molten grey cast iron. When Mg (magnesium) added to graphite cast iron, it forms nodules instead of flakes. In this article, you’ll learn about Nodular cast iron.

Nodular cast iron is also known as ductile cast iron, spheroidal cast iron or SG iron.

Problem with Grey Cast Iron

Gray cast iron consists of graphite flakes. These flakes make the cast iron brittle and thus a problem for steelmakers.

If you consider the flakes in the cast iron, each flake has very fine ends. Due to the small area at the end of graphite flakes, once the load is applied to the material it can cause heavy stress concentration at the tip. This stress concentration can cause cracks at the tip and cause the material to fail.