581. The height of the down sprue is 175 mm and its CS are at the base is 200 mm². The CS area of the horizontal runner is also 200 mm². Assuming no losses, indicate the correct choice for-the time (second) required to fill a mould cavity of volume 10^6mm3. (Use g = 10 m/s²)

1. 1. 2.67

   
   
   

   2. 8.45

   
   
   

   3. 26.7

   
   
   

   4. 84.50

   
   
   

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1. View Hint View Answer Discuss in Forum

   V_s = √2 × 10 × 175 × 10⁻³
   = 1870 mm/s
   Pouring time
   

   t =	106
   	200 × 1870

   
   t = 2.67 m/s

   Correct Option: C

   V_s = √2 × 10 × 175 × 10⁻³
   = 1870 mm/s
   Pouring time
   

   t =	106
   	200 × 1870

   
   t = 2.67 m/s

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582. According to Chvorinov's rule, the solidification time of a casting is proportional to (Volume/ surface area)ⁿ, where 'n' equals to

1. 1. 0.5

   
   
   

   2. 1

   
   
   

   3. 2

   
   
   

   4. 4

   
   
   

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1. View Hint View Answer Discuss in Forum

   t = k		V		2
   		A

   
   n = 2

   Correct Option: C

   t = k		V		2
   		A

   
   n = 2

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583. Application
     A. Undercut in components
     B. Large bells
     C. Mass production of casting by machine moulding
     D. Components with irregular parting lines
     Type of pattern
     1. Cope and drag
     2. Follow board
     3. Gated
     4. Loose piece
     5. Sweep

1. 1. A – 1, B – 5, C – 3, D – 4

   
   
   

   2. A – 5, B – 4, C – 3, D – 1

   
   
   

   3. A – 4, B – 5, C – 1, D – 3

   
   
   

   4. A – 4, B – 5, C – 3, D – 1

   
   
   

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1. View Hint View Answer Discuss in Forum

   A – 4, B – 5, C – 3, D – 1

   Correct Option: D

   A – 4, B – 5, C – 3, D – 1

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584. Chaplets are placed between mould in order to

1. 1. promote directional solidification

   
   
   

   2. help alloying the metal

   
   
   

   3. facilitate easy removal of core from casting

   
   
   

   4. prevent core movement due to buoyancy

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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585. The primary function of a riser is to

1. 1. feed molten metal to casting as it solidifies

   
   
   

   2. prevent atmospheric air from contaminating the metal in the mould

   
   
   

   3. allow gases to easily escape from mould cavity

   
   
   

   4. allow molten metal to rise above the mould cavity

   
   
   

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1. View Hint View Answer Discuss in Forum

   Riser is used to compensate liquid shrinkage & phase transition shrinkage.

   Correct Option: C

   Riser is used to compensate liquid shrinkage & phase transition shrinkage.

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