The GATE Grind

GATE 2026 ME – Question 30

Casting, Forming and Joining Processes · Casting: patterns, moulds, cores, solidification, riser and gating design, defects · 1 mark · Multiple choice

In relation to metal casting defects, match the following

DefectDescription
PDrossIShallow blow found on a flat casting surface
QScabIILighter impurities appearing on the top surface of a casting
RScarIIIA rough, thin layer of metal, protruding above the casting surface, on top of a thin layer of sand
  1. P-II, Q-III, R-I
  2. P-II, Q-I, R-III
  3. P-III, Q-I, R-II
  4. P-III, Q-II, R-I

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Show answer and explanation

Correct answer: (A) P-II, Q-III, R-I

Explanation

Dross is made of lighter impurities that float to the top of the casting, so P goes with II. A scab is a rough, thin layer of metal sitting above the casting surface on a thin layer of sand, so Q goes with III. A scar is a shallow blow on a flat surface, so R goes with I.