A plain carbon steel having $0\mathrm{.}5\%$ C is heat treated in a mixture of gases Methane$-$HydrogenNitrogen can be used to prepare a protective atmosphere for this steel. Suppose that the gas mixture contains $20\%$ by volume of nitrogen and that the total pressure in the furnace is $1\mathrm{.}1$ atm. a$)$ Calculate the composition of the gases that will be necessary to keep the carbon content of the steel unchanged during the heat treatment process at $1000$C$.$ The activity of carbon in this steel is $0\mathrm{.}2$ at $1000$C$.$ b$)$ We would like to decrease the surface carbon content of the steel to $0\mathrm{.}3$ wt $\%$ carbon level by decarburizing it in the gas atmosphere. What should be the composition of the MethaneHydrogen$-20\%$ Nitrogen gas mixture for this purpose at $1000$C and $1\mathrm{.}1$ atm total pressure? The activity of carbon in the steel containing $0\mathrm{.}3\%$ C at $1000$C is $0\mathrm{.}1.$ DATA C $+2$H$2=$ CH$4$G$=-90420+110$ T joule$/$moleA plain carbon steel having $0\mathrm{.}5\%C$ is heat treated in a mixture of gases Methane$-$Hydrogen$-$

Nitrogen can be used to prepare a protective atmosphere for this steel. Suppose that the gas mixture

contains $20\%$ by volume of nitrogen and that the total pressure in the furnace is $1\mathrm{.}1$atm.

a$)$ Calculate the composition of the gases that will be necessary to keep the carbon content of the

steel unchanged during the heat treatment process at $1000C.$ The activity of carbon in this steel

is $0\mathrm{.}2$ at $1000C.$

b$)$ We would like to decrease the surface carbon content of the steel to $0\mathrm{.}3wt\%$ carbon level by

decarburizing it in the gas atmosphere. What should be the composition of the Methane$-$

Hydrogen$-20\%$ Nitrogen gas mixture for this purpose at $1000C$ and $1\mathrm{.}1$ atm total pressure?

The activity of carbon in the steel containing $0\mathrm{.}3\%C$ at $1000C$ is $0\mathrm{.}1.$

DATA

$\{\begin{array}{c}\text{:}[C+2H_2=C{H}_4]\\ R=8\mathrm{.}314& \text{j}\text{o}\text{u}\text{l}\frac{e}{m}\text{o}\text{l}\text{e}& K\end{array},G=-90420+110T,$ joule $\frac{?}{?}$ mole