I guess Fe3C will nucleate first. At 723 degree C, carbon diffusion is faster than Fe which helps carbon to cluster around Austenite GB, and if it's 25 atom percent, Fe3C will form.
Sir I have 2 doubts 1) Eutectoid steels have structure of Pearlite alone or phases of ferrite and Cementite. 2) Hypo eutectoid steels have structure of Pearlite alone or phases of ferrite and pearlite. Which is correct sir.
Pearlite itself is a mixture of ferrite and cementite. Eutectoid steel will give only pearlite. Hypoeutectoid steel will have both pearlite and some ferrite, called proeutectoid ferrite, which is not part of the mixture.
Sir, above 725 degrees Celsius it is Gamma austenite right sir , it is not steel .?? Steel is only below 725 centigrade and at 0.8 it is eutectoid steel. So how come above above 725 at 0.8 composition it is eutectoid steel?
Irrespective of temperature and microstructure we will call an alloy of Fe and C containing 0.8% C as eutectoid steel. Similarly for hypo and hypereutectoid steels.
Well, Fe-C diagram is the best practical example of eutectoid phase diagram. All heat treatment of steels depends essentially on controlling the eutectoid reaction.
yeah .. how the eutectoid start at 0.8 wt% of carbon after that i get 0.02wt% c for alpha and 6.7 wt% c for fe3c .. the total carbon in the composition is 6.72 wt%c when the reactoin start at 0.8 wt% c i dont understand that ..from where the exceed carbon come ?..please explain ?
@@anasalazazmeh5749 Hey I think u have misunderstood. The carbon is conserved. see the fe3c by percentage will be less in the total sum and alpha will be more it is not 50% alpha 50% fe3c
