CASTING

                                         CASTING
                  Casting process is based on the property of a liquid to take up the shape of the vessel containing it. Molten metal poured into a mould flows into the corners and fills all the voids. When metal solidifies it takes the shape of the mould not exactly the same because solid being denses there is reduction of volume. For obtaining correct dimension, provision needs to be made for shrinkage of metal. Hollow components can be produced by inserting a core into the cavity in the mould.

               Casting is one of the most versatile forms of mechanical process for producing components, because there is no limit to the size, shape and intricacy of the article that can be produced by Casting. It offers one of the cheapest methods and gives high strength rigidity even to intricate parts, which are difficult produced by other methods of manufacturing. One of the most attractive features of casting is its ability to form any shape in one operation. This result in saving labour cost and avoids any problem which might arise in joining sub-assembly together in casting high degree reproducibility is possible. Ones the shape of mould has been established, control of melting and pouring conditions ensure that all casting are identical casting process the complete range of mechanical and physical properties.

               Principle of casting consists of introducing the metal into a cavity and mould of the desired shape and alloying it to solidify. When it is removed from the mould, the casting is of same shape built slightly smaller, due to contraction of metal. The molten metal passes through the four stages (liquid stage, mushy stage, plastic stage, and solid stage) till the solidification takes place the metal with in a solidification range is at mushy stage. Contraction of metal begins immediately this range over and the metal comes into plastic stage.

Types of casting process:

A. Sand casting 
B. Gravity die casting
C. Chilled die casting 

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