(a) Pearlitic ductile cast iron and ferritic ductile cast iron differ only in how quickly they are cooled. Why does slow cooling give a different result that fast cooling?

(b) Can you transform a piece of ferritic ductile cast iron into a piece of pearlitic ductile cast iron without melting it? If so, how?

(c) Suppose you have some ferritic ductile cast iron at 3.0 wt% C. You first austenitize this and then quench very rapidly to room temperature. What is the likely resulting microstructure?

Duration of precipitation heat treatment ( h) (a)