Q58
White cast iron
A.
Contains 1.7 to 3.5% carbon in Free State and is obtained by the slow cooling of molten cast iron
B.
Is also known as chilled cast iron and is obtained by cooling rapidly. It is almost unmachinable
AnswerC.
Is produced by annealing process. It is soft, tough and easily machined metal
D.
Is produced by small additions of magnesium (or creium) in the ladle. Graphite is in nodular or spheroidal form and is well dispersed throughout the material
Answer: Option B
Solution
Answer: Option B
Solution:
White cast iron Is also known as chilled cast iron and is obtained by cooling rapidly. It is almost unmachinable.White cast iron is a cast iron without any alloy addition and with low C and Si content such that the structure is hard brittle iron carbide with no free graphite.
A fast cooling rate prevents the precipitation of C as graphite.