Free carbon in iron makes the metal

hard and gives a fine grained crystalline structure

cupola furnace

Cast iron is manufactured in Cupola furnace.

Cupola Furnace is a melting device which used to melt cast iron, Bronze and other alloying elements are melted. It is mainly used to convert pig iron to cast iron.

Cupola furnace is employed for melting scrap metal or pig iron for production of various cast irons. It is also used for production of nodular and malleable cast iron.

brittle material

Brittleness
Brittleness is a property of material which breaks with little or no deformation.

all of these

Cast iron has
* high compressive strength
* excellent machinability
* good casting characteristic