Question

Which one of the following is the correct statement in a centrifugal method?

1. No core is used
2. Core may be made of any metal
3. Core is made of sand
4. Core is made of ferrous metal

Answer 1

Correct Answer - Option 1 : No core is used

Explanation:

Centrifugal casting:

This is a process where the mould is rotated rapidly about its central axis as the metal is poured into it. Because of the centrifugal force, a continuous pressure will be acting on the metal as it solidified the slag, oxide and other inclusion being lighter, gets separated from the metal and segregates towards the centre.

Core:

It is used for making hollow cavities in castings. A core is made from chemically bound sand so when the casting has solidified, the sand can be broken down and removed from the casting. We generally use three different types of cores.

• Cylinder Cores
• Balanced Cores
• Dovetail Cores

In centrifugal casting, there is no requirement of any core for the making of the concentric hole. As the metal is always pushed outward because of the centrifugal force, the application of the core is eliminated.

Classification of casting:

Temporary Moulds (Expendable moulds):

1. Sand Casting
2. Shell castings
3. Investment castings
4. Full moulding
5.  CO₂ moulding

Metallic Moulds (Permanent moulds)

1. Centrifugal casting
2. Die casting
   1. Gravity casting
   2. Pressure casting
      1. Hot (suitable for Pb, Sn, Zn, alloy).
      2. Cold (suitable for Al & Cu, alloy).
3. Slush casting