Question

Cast iron is a:
A.Malleable material
B.Ductile material
C.Brittle material
D.Tough material

Answer 1

Hint: Cast iron is a combined group of alloys of iron and carbon having a carbon content of more than 2% and less than 4% in addition to varying amounts of manganese, silicon and traces of phosphorus and sulphur.

Complete answer:
Cast iron contains around 2 to 4% of carbon as impurity and is the second most impure form of iron after pig iron which contains more than 4% of carbon impurity along with traces of silicon, phosphorus, manganese and sulphur. Cast iron is prepared when pig iron is remelted and then cast into metal parts.
Cast iron is a hard and brittle material.

Thus, the correct answer is C.

Note:
-Cast iron is produced by various heat treatments and processing techniques. As a result, different types of cast iron are produced namely, grey cast iron, white cast iron, ductile cast iron, graphite cast iron and malleable cast iron.
-Gray iron has a characteristic flake shape of the graphite molecules that are present in the metal and also responsible for its colour.
-White iron is produced on shearing of the grey iron which results in loss of graphite molecules.
-Malleable cast iron has a structure that consists of temper carbon, pearlite and ferrite. It has properties in its microstructure that make it ideal for use where toughness and malleability are required. It is formed by heating white cast iron at high temperatures and then cooled very slowly.
-Ductile iron possesses special properties due to the presence of magnesium metal in the alloy
-Graphite iron has a structure like graphite and shows properties similar to both grey and white iron.