The iron obtained from the blast furnace is known as pig or cast iron. Because of the presence of impurities, such as carbon, it has a hard and brittle nature. Most of this type of iron is therefore converted into steel in the basic oxygen process. 

During this process either all or some of the carbon is removed. Calculated quantities of other elements are then added to produce the required type of steel.

a. Explain the meaning of the term alloy as applied to steel.

b. Name two impurities, other than carbon, which are present in cast iron and which are removed completely during the steel manufacture.

c. Describe the method of steel manufacture used which removes the impurities referred to in b. 

d. Name two metallic elements which may be added to the basic oxygen furnace to produce different varieties of steel.

e. Give two uses of stainless steel.

f. Give two advantages of stainless steel compared with cast iron.