Fundamental of Metal Casting:
Fundamental of Metal Casting : Casting process is based on the property of a liquid to take up the shape of 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 mould but not exactly the same because solid being. denser there is reduction of volume (2 to 9%). For obtaining correct dimensions, provision needs to be made for shrinkage of metal. Hollow components can be produced by inserting a core into the cavity in the mould.
Sand Casting : Sand castings are porous enough and, therefore, cannot be used for pressure sight vessels. Structure obtained by sand casting is loose and hence not stranger than wrought products. As the grains are not close, the casting has lower density and poor strength. Sand casting has poor ductility.
Shell-mould Casting : This is variant of the resin bonded sand technique for casting steel, iron or non-ferrous alloys.
The mould is formed from a mixture of fine sand (100 - 150 mesh) and a thermosetting resin binder that is placed against a heated metal pattern, preferably made of grey cast iron.