Topic: Material Science
In nodular iron, graphite is in the form of-
- A. Cementite
- B. Free carbon
- C. Flakes
- D. Spheroids
Answer: D. Spheroids
Explanation: Nodular (or Ductile) Cast Iron- Nodular cast iron has also known as spheroidal or ductile cast iron. Alloying additions are of prime importance in producing these materials. Small additions of Mg/Ce to the gray cast iron melt before casting can result in graphite to form nodule or spheroids like particles. Matrix surrounding these particles can be either ferrite or pearlite depending on the heat treatment. These are stronger and ductile than gray cast iron.