I want to calculate the equilibrium pearlite, ferrite and bainite phase fraction below eutectoid temperature using the extended Acm and alpha/alpha and gamma line
Dear Kirty
can you explain the figure 1.PNG?
Especially the "extended Acm" and "alpha/alpha gamma line".
Is "Cc" the composition of wt % Carbon, which is 0.2?
Another thing:
In the phase diagram of Fe-C,
all the phases are equilibrium phases,
which are the product of a very slow cooling/heating process.
Thus from the diagram, we can calculate the % of all equilibrium phases of:
- Ferrite
- Austenite
- Pearlite
- Cemetite
But not Bainite, since Bainite is a non-equilibrium phase.
Bainite is meta stable, produced from a 'quite rapid' cooling process of Austenite.
Bainite can be measured from a Time-Temperature -Transformation (TTT) Diagram
for a particular % of Carbon.
Different %C of steel will have their own different TTT Diagram.
So it is better for you to refer to the TTT Diagram of "low alloy steel -C-0.2,Mn-0.8,Si0.2" to calclate the Bainite.
Dear Joy,
Thanks for your reply. Yes, Cc is the composition of wt % Carbon, which is 0.2. I know that Fe-C diagram is meant for calculating the equilibrium phases whereas for calculating the non equilibrium phase we need to look at the TTT/CCT curve. But I read in a thesis where there was a method for calculating the bainite transformation by extending the Acm and Ae2 line of phase diagram.I got the extended line from ThermoCalc software.
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