Solidification time of a molten metal in a casting is proportional to (where, V = volume of metal & A = its surface area; in the casting) ?

Related Mcqs:

1. Titanium is added to molten aluminium alloys before casting for the purpose of_____________________?

   A. Grain refinement
   B. Increasing corrosion resistance
   C. Reducing porosity
   D. Improving fluidity

2. Volume of blast furnace slag is about _______________ times the volume of hot metal (pig iron) of the same weight ?

   A. 1.5
   B. 3
   C. 5
   D. 7

3. Oxide layer formed on the non-ferrous metal surface after its annealing is__________________?

   A. Removed by acid pickling
   B. Hammered into the surface
   C. Removed with coarse emery cloth
   D. Left as such to protect the surface

4. ____________ is the process used for setting up compressive stresses in the surface of a metal to improve its fatigue strength ?

   A. Lancing
   B. Shot peening
   C. Slugging
   D. Spinning

5. Yield strength of a polycrystalline metal with an average grain size „d’, is proportional to ____________________?

   A. d1/2
   B. d-1/2
   C. d
   D. d-1

6. Insulation of liquid surface can be achieved by _____________ on top of its surface?

   A. Floating hollow polypropylene spheres
   B. Spraying alumina powder
   C. Putting cement
   D. None of these

7. Dephosphorization of molten pig iron is favoured by_______________________?

   A. Oxidising and basic slag
   B. Reducing and basic slag
   C. High activity co-efficient of phosphorous in metal
   D. Oxidising and neutral slag

8. Damage to metal surface by mechanical action is called____________________?

   A. Pitting
   B. Corrosion
   C. Erosion
   D. None of these

9. Normalising of a casting does not__________________?

   A. Induce stresses in it
   B. Refine its grain structure
   C. Reduce segregation
   D. Improve its mechanical properties

10. The most suitable material for die casting is __________________?

    A. Iron
    B. Copper
    C. Steel
    D. Nickel