A hypoeutectoid plaincarbon steel that was slowcooled from t

A hypoeutectoid plain-carbon steel that was slow-cooled from the austenite region to room temperature contains 8.8 wt% eutectoid ferrite. Assuming no change in structure just below the eutectoid temperature to room temperature, what is the carbon content of the steel.

Solution

the carbon content in the steel wwould be 0.83% beacause if we look at the iron carbon diagram and from the austenite region we are moving towards the room temperature by slow cooling into the eutectoid region and assuming there is no change in microstructure ..... that is only possible when line passes through the sepration point of Pearlite-ferrite and pearlite-cementite, if we mark a straight line from this point on the abcissa of the diagram, the carbon content would be 0.83%.