Answer the following questions using the phase diagram of the iron$-$carbon system.

a$)$ A plain carbon steel contains $60$ wt $\%$ ferrite and $40$ wt $\%$ pearlite. Estimate the carbon

content of the steel.

b$)$ This steel is heat treated under a CO$2-$CO$-10\%$ N$2$ gas mixture at $900$C$.$ Total pressure in the

furnace is $0\mathrm{.}9$ atm. Calculate the composition of the CO$2-$CO$-10\%$ N$2$ gas atmosphere that will

keep the carbon content of the steel unchanged throughout the heat treatment.

c$)$ What will be the carbon content of the affected zone of the steel if the composition of gas

mixture used for the heat treatment purpose in part $($b$)$ consists of $80\%$CO$-20\%$CO$2$ without

changing the total pressure $(0\mathrm{.}9$ atm$)$ in the furnace? Briefly explain your reasoning.

d$)$ What will be the carbon content of the affected zone of the steel if the composition of gas

mixture used for the heat treatment purpose in part $($b$)$ consists of $78\%$CO$-12\%$CO$2-10\%$N$2$

without changing the total pressure $(0\mathrm{.}9$ atm$)$ in the furnace? Briefly explain your reasoning.

e$)$ We would like to change the surface carbon content of the steel to $0\mathrm{.}6$ wt$\%$ carbon by heat

treating it at $900$C in a CO$2-$CO gas atmosphere without changing the total pressure $(0\mathrm{.}9$ atm$)$

in the furnace. What should be the composition of the CO$2-$CO gas mixture?

C $+$ O$2=$ CO$2$G$=-394184-0\mathrm{.}84$ T joule$/$mole

C $+1/2$ O$2=$ CO $$G$=-111727-87\mathrm{.}66$ T joule$/$mole

R$=8\mathrm{.}314$ joule$/$mol degree.Answer the following questions using the phase diagram of the iron$-$carbon system.

a$)$ A plain carbon steel contains $60wt\%$ ferrite and $40wt\%$ pearlite. Estimate the carbon

content of the steel.

b$)$ This steel is heat treated under a $C{O}_2-CO-10\%N_2$ gas mixture at $900C.$ Total pressure in the

furnace is $0\mathrm{.}9$atm. Calculate the composition of the $C{O}_2-CO-10\%N_2$ gas atmosphere that will

keep the carbon content of the steel unchanged throughout the heat treatment.

c$)$ What will be the carbon content of the affected zone of the steel if the composition of gas

mixture used for the heat treatment purpose in part $($b$)$ consists of $80\%CO-20\%C{O}_2$ without

changing the total pressure $(0\mathrm{.}9$atm$)$ in the furnace? Briefly explain your reasoning.

d$)$ What will be the carbon content of the affected zone of the steel if the composition of gas

mixture used for the heat treatment purpose in part $($b$)$ consists of $78\%CO-12\%C{O}_2-10\%N_2$

without changing the total pressure $(0\mathrm{.}9$atm$)$ in the furnace? Briefly explain your reasoning.

e$)$ We would like to change the surface carbon content of the steel to $0\mathrm{.}6wt\%$ carbon by heat

treating it at $900C$ in a $C{O}_2-CO$ gas atmosphere without changing the total pressure $(0\mathrm{.}9$atm$)$

in the furnace. What should be the composition of the $C{O}_2-CO$ gas mixture?

$C+O_2=C{O}_2,G=-394184-0\mathrm{.}84T$ joule $\frac{?}{\text{m}\text{o}\text{l}\text{e}}$

$C+\frac{1}{2}{O}_2=CO,G=-111727-87\mathrm{.}66T$ joule $\frac{?}{\text{m}\text{o}\text{l}\text{e}}$

$R=8\mathrm{.}314$ joule $\frac{?}{\text{m}\text{o}\text{l}}$ degree.