Question

Match the casting defects in Column I with the characteristic features in Column II. 

• A. P – 2, Q – 4, R – 3, S – 1
• B. P – 1, Q – 3, R – 2, S – 4
• C. P – 1, Q – 2, R – 4, S – 3
• D. P – 2, Q – 4, R – 3, S – 1

Hint:

When analyzing casting defects, consider the nature of the defect (e.g., premature solidification, gas evolution, metal penetration) and match it with the characteristic features like cracking, porosity, or incomplete filling of molds.

Answer 1

The Correct Option is D

Let’s analyze each casting defect and its corresponding characteristic feature: - P. Misrun: A misrun occurs when the metal solidifies prematurely in the mold, and some sections of the casting are not filled. This is associated with 2. Metal solidifies prematurely in the mould and some sections of the casting are not filled.
- Q. Expansion scab: This defect is caused by the penetration of liquid metal behind the surface layer of sand molds. Therefore, Q corresponds to 1. Penetration of liquid metal behind surface layer of sand molds.
- R. Pin holes: Pin holes are tiny holes in the casting due to the evolution of gases during solidification, resulting in porosity. Hence, R corresponds to 4. Evolution of gases during solidification resulting in porosity.
- S. Hot tearing: Hot tearing is a form of cracking that occurs because of restraint to contraction in certain areas of the casting during solidification and cooling to room temperature. So, S corresponds to 3. Cracking because of restraint to contraction in certain areas of the casting during solidification and cooling to room temperature.
Thus, the correct matching is:
- P – 2: Misrun with metal solidifying prematurely in the mold
- Q – 1: Expansion scab with penetration of liquid metal behind surface layer
- R – 4: Pin holes with evolution of gases resulting in porosity
- S – 3: Hot tearing with cracking due to restraint to contraction during solidification
Therefore, the correct option is Option D.