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((( English caption v0.1 ))) ((( by agungedukasi )))
next, we will learn about Iron-Carbon Phase Diagram
Iron-Carbon Phase Diagram
will be more complex
as compared to Simple-Binary Phase Diagram
here I will draw
we have...
Iron
Carbon
composition
in weight percent (%)
zero
here we will
until 6.7% Carbon
in the previous video, we wrote here as 100%
but in this Iron-Carbon phase diagram
usually we use
Carbon
less than 6.7%
also, since this phase diagram is more complex
it is easier to draw it
from 0 to 6.7% Carbon composition
Y axis is the Temperature
in degree Celcius
Y axis is from 400 degree Celcius
to 1600 degree Celcius
OK
here we've got Alpha phase
Gamma phase
and beyond this point
far away, there is
Fe3C phase
over there, at 100% Carbon
in that region
there is Fe3C phase
OK
here is
Delta phase
Alpha dan Gamma phase form ...
Alpha + Gamma phase
Alpha and Fe3C form ...
Alpha + Fe3C phase
Gamma and Fe3C (beyond there) form
Gamma + Fe3C phase
here is Liquid
Gamma and Liquid form ...
Gamma and Liquid phase
I will write down ...
the temperature at this point is 912 degree Celcius
1394 degree Celcius
1538 degree Celcius
4.3 weight percent
2.14 weight percent
0.76 weight percent
7277 degree Celcius
OK
so here
I will explain what is Alpha
Alpha is Ferrite
and then Gamma
Gamma is Austenite
and the we have
Fe3C
Fe3C is Cementite
there is Delta phase over here
Delta is also Ferrite but
it is a Ferrite at high temperature
above 1394 degree Celcius
usually we are not interested
in this phase
we are interested to the phase below
OK
so
we can see over here
that we have
Iron
an Iron (e.g. 99.999% purity) has
melting point of
1538 degree Celcius
beyond this temperature
it will change to liquid
if we mix it with Carbon
the melting point will be going down
relative to this point
why we must mix
iron and carbon
because
from these phases
there are those which has
the strength
higher than
or
have properties that are better
as compared with pure iron
those are the usefulness of phase diagram
and
actually
in a practical world
we use TTT diagram
that I will present in the next video
in the series
please note that
here we've got
Eutectic point
Eutectic is whe we have liquid
let say we have iron with 4.3% carbon
decedent simple rent but want to get a center byron
initially it's at this temperature
then we cool it down
it will pass through this point
of Eutectic
where Liquid transform to two solid solutions
Liquid transform to Gamma and Fe3C
It is called Eutectic
here we've got Eutectoid
Eutectoid
happen when
during cooling down
transform from a solid solution phase to two different solid solution phase
here
Gamma cooled down
transform to
Alpha + Fe3C
that's all for Iron Carbon
Phase Diagram
((( English caption v0.1 ))) ((( by agungedukasi )))
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