Question

Match List I with List II

LIST I (Material)	LIST II (Form of Microstructure)
A. Gray Cast Iron	I. Presence of large amount of iron carbide
B. White Cast Iron	II. Graphite in the form of spheroid
C. Ductile Cast Iron	III. Graphite exists as rosettes in ferrite or pearlite matrix
D. Malleable Cast Iron	IV. Graphite in the form of flakes

Choose the correct answer from the options given below:

• (A) - (I), (B) - (II), (C) - (III), (D) - (IV)
• (A) - (IV), (B) - (I), (C) - (II), (D) - (III)
• (A) - (I), (B) - (III), (C) - (IV), (D) - (II)
• (A) - (IV), (B) - (I), (C) - (III), (D) - (II)

Hint:

Graphite form influences the mechanical properties of cast iron Flakes reduce strength while spheroidal or rosette formations increase ductility and toughness

Answer 1

The Correct Option is B

Material-microstructure pairings are as follows:

• Gray Cast Iron: Graphite flakes (IV)
• White Cast Iron: Predominantly iron carbide (I)
• Ductile Cast Iron: Spheroidal graphite (II)
• Malleable Cast Iron: Rosette-shaped graphite in ferrite or pearlite (III)

Explanation:

- Gray Cast Iron: Composed of graphite flakes, it offers high damping but low tensile strength.
- White Cast Iron: Its microstructure is hard and brittle due to iron carbide (cementite).
- Ductile Cast Iron: Contains spheroidal graphite, providing good ductility and toughness.
- Malleable Cast Iron: Rosette-shaped graphite makes it malleable and improves machinability.

Correct Answer: 2. (A) - (IV), (B) - (I), (C) - (II), (D) - (III)