Q146
Malleable 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
C.
Is produced by annealing process. It is soft, tough and easily machined metal
AnswerD.
Is produced by small additions of magnesium (or cerium) in the ladle. Graphite is in the nodular or spheroidal form and is well dispersed throughout the material
Answer: Option C
Solution
Answer: Option C
Solution:
Malleable iron is cast as white iron, the structure being a metastable carbide in a pearlitic matrix.Through an annealing heat treatment, the brittle structure as first cast is transformed into the malleable form.