Match the casting defects (Group A) with the probable causes (Gro

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
S : Cold shut	4 : Differential cooling rate

A. P – 1, Q – 3, R – 2, S – 4

B. P – 4, Q – 3, R – 2, S – 1

C. P – 3, Q – 4, R – 2, S – 1

D. P – 1, Q – 2, R – 4, S – 3

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Concept:

The various defects of the welding are as follows:

DEFECT	DESCRIPTION	DIAGRAM
Hot Tear	Due to non-uniform cooling, internal stress will be developed in casting and fracture occurs on surface
Shrinkage	Volumetric contraction both in solid and liquid state. Shrinkage due to thermal contraction of liquid convert to solid state.
Blow Hole	Low permeability of the sand mould. It is gas defect which is formed on the surface of casting is open blows and which formed inside the casting is called as blow holes.
Cold Shut	Improper fusion of two streams of liquid metal