421. Match the casting defects (Group A) with the probable causes (Group B):
     Group-A
     P. Hot tears
     Q. Shrinkage
     R. Blow holes
     S. Cold shunt
     Group-B
     1. Improper fusion of two streams of liquid metal
     2. Low permeability of the sand mould
     3. Volumetric contraction both in liquid and solid stage
     4. Differential cooling rate

1. 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-4, R-4, S-3

   
   
   

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1. View Hint View Answer Discuss in Forum

   P – 3, Q – 4, R – 2, S – 1

   Correct Option: B

   P – 3, Q – 4, R – 2, S – 1

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422. During solidification of a pure molten metal, the grains in the casting near the mould wall area

1. 1. coarse and randomly oriented

   
   
   

   2. fine and randomly oriented

   
   
   

   3. fine and ordered

   
   
   

   4. coarse and ordered

   
   
   

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1. View Hint View Answer Discuss in Forum

   coarse and ordered

   Correct Option: D

   coarse and ordered

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423. Green sand mould indicates that

1. 1. polymeric mould has been cured

   
   
   

   2. mould has been totally dried

   
   
   

   3. mould is green in colour

   
   
   

   4. mould contains moisture

   
   
   

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1. View Hint View Answer Discuss in Forum

   mould has been totally dried

   Correct Option: B

   mould has been totally dried

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424. While cooling, a cubical casting of side 40 mm undergoes 3%, 4% and 5% volume shrinkage during the liquid state, phase transition and solid state, respectively. The volume of metal compensated from the riser is

1. 1. 2%

   
   
   

   2. 7%

   
   
   

   3. 8%

   
   
   

   4. 9%

   
   
   

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1. View Hint View Answer Discuss in Forum

   The riser can compensate for volume shrinkage only in the liquid stage and transition stage and not in the solid state.
   Hence volume of metal that needs t o be compensated from the riser = 3 + 4 = 7%

   Correct Option: B

   The riser can compensate for volume shrinkage only in the liquid stage and transition stage and not in the solid state.
   Hence volume of metal that needs t o be compensated from the riser = 3 + 4 = 7%

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425. Which of the following engineering materials is the most suitable candidate for hot chamber die casting?

1. 1. low carbon steel

   
   
   

   2. titanium

   
   
   

   3. copper

   
   
   

   4. tin

   
   
   

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1. View Hint View Answer Discuss in Forum

   For hot chamber die casting, titanium is used.

   Correct Option: D

   For hot chamber die casting, titanium is used.

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