Question

Compute the weight fraction of graphite, in a 3 wt% C Ferritic Gray cast iron, assuming that all the carbon exists as the graphite phase. Assume densities of 7.9 and 2.3 g/cm3 for ferrite and graphite, respectively.

Answer 1

9.60%

Step-by-step explanation:

Computation for the weight fraction of graphite

First step

Computation for the mass fraction for Wa using this formula

Wa=Cg-Co/Cg-Ca

Let plug

Wa=10-3/100-0

Wa=0.97

Computation for the mass fraction for Wg using this formula

Wg=Co-Ca/Cg-Ca

Let plug in the formula

Wg=3-0/100-0

Wg=0.03

Second step is to convert the mass fraction to Volume Fraction using this formula

Volume Fraction =[Wg/Pg÷(Wa/Pa)+(Wg/Pg)]*100

Let plug in the formula

Volume =[0.03/2.3 ÷(0.97/7.9)+(0.03/2.3)]*100

Volume=[0.0130435÷0.1227848+0.0130435]*100

Volume=[0.0130435÷0.135828]*100

Volume=0.096*100

Volume=9.60%

Therefore the weight fraction of graphite will be 9.60%