Q238
Ductile 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
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
AnswerAnswer: Option D
Solution
Answer: Option D
Solution:
Ductile cast iron 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 materialductile iron has much more impact and fatigue resistance, due to its nodular graphite inclusions.