576. Thread rolling is restricted to

1. 1. ferrous materials

   
   
   

   2. ductile materials

   
   
   

   3. hard materials

   
   
   

   4. None of these

   
   
   

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   Intricate Deformation can take place only in Ductile material.

   Correct Option: B

   Intricate Deformation can take place only in Ductile material.

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577. While rolling a strip the peripheral velocity of the roll is.... A.... than the entry velocity of the strip and is... B... the exit velocity of the strip.

1. 1. less than/greater than

   
   
   

   2. greater than/less than/equal to

   
   
   

   3. less than

   
   
   

   4. greater than

   
   
   

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   At entry, plate velocity is smaller than Roll velocity then it increases & becomes equal to roll velocity at Neutral plane after that it is higher than the roll velocity.

   Correct Option: A

   At entry, plate velocity is smaller than Roll velocity then it increases & becomes equal to roll velocity at Neutral plane after that it is higher than the roll velocity.

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578. Gating ratio of 1: 2: 4 is used to design the gating system for magnesium alloy casting. This gating ratio refers to the cross-section areas of the various gating elements as given below:
     1. Down sprue
     2. Runner
     3. Ingates
     The sequence of the above elements in the ratio 1: 2: 4 is

1. 1. 1, 2 and 3

   
   
   

   2. 1, 3 and 2

   
   
   

   3. 2, 3 and 1

   
   
   

   4. 3, 1 and 2

   
   
   

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   Spruce base: Runner: Ingates

   Correct Option: B

   Spruce base: Runner: Ingates

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579. A 10 mm thick steel bar is to be horizontally cast with two correctly top risers of adequate feeding capacity. Assuming end effect without chill, what should be the theoretical length of the bar?

1. 1. 96 mm

   
   
   

   2. 132 mm

   
   
   

   3. 192 mm

   
   
   

   4. 156 mm

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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580. The permeability of moulding sand was determined using a standard AFS sample by passing 2000 cc of air at a gauge pressure of 10 g/cm². If the time taken for the air to escape was 1 min, the permeability number is

1. 1. 112.4

   
   
   

   2. 100.2

   
   
   

   3. 75.3

   
   
   

   4. 50.1

   
   
   

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1. View Hint View Answer Discuss in Forum

   PN =	VH	=	2000 × 5.08
   	pAT		10 ×	π	(5.08)2 × 1
   				4

   
   PN = 50.12

   Correct Option: A

   PN =	VH	=	2000 × 5.08
   	pAT		10 ×	π	(5.08)2 × 1
   				4

   
   PN = 50.12

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