Question

Spheroidal grey cast iron (SG Iron) will be produced by:

• A. Controlling carbon content
• B. Inoculation with Mg
• C. Malleablisation treatment
• D. Controlling Carbon Equivalent

Hint:

Spheroidal graphite (SG) iron is produced by adding magnesium to molten iron, which transforms graphite flakes into spheroids, enhancing toughness and ductility.

Answer 1

The Correct Option is B

Spheroidal graphite iron (also known as ductile iron or SG iron) is a type of cast iron in which the graphite is present in the form of spherical nodules instead of flakes. This structure improves ductility and strength.
To achieve this nodular structure, molten cast iron is treated with a small amount of magnesium (Mg) or cerium. This process is known as inoculation.
Magnesium modifies the graphite morphology, promoting the formation of spheroids instead of flakes during solidification. Other options like controlling carbon or carbon equivalent affect general properties but do not result in nodular graphite formation.