Multiple choice

Match the casting defects (Group A) with the probable causes (Group B).

     
Group A
Group B
P Hot tears 1 Improper fusion of two streams of liquid metal
Q Shrinkage 2 Low permeability of the sand mould
R Blow holes 3 Volumetric contraction both in liquid and solid stage
4 Stresses in different regions of metal

  1. P - 1, Q - 3, R - 2, S - 4

  2. P - 4, Q - 3, R - 2, S - 1

  3. P - 3, Q - 4, R - 2, S - 1

  4. P - 1, Q - 2, R - 4, S - 3
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(P) Hot tears is a metallurgical defect and occurs because of differential cooling rate, which creates stresses in the different regions of metal. (Q) Shrinkage occurs because of volumetric contraction as volume gets reduced during cooling. (R) Blow holes is a gas defect which occurs due to low permeability of sand mould. (S) Cold shut is pouring metal which appears due to improper fusion of two streams of liquid metal.

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