Looking at the steel microstructure below what would be the

Looking at the steel microstructure below, what would be the minimum carbon content of this steel? The minimum carbon content of this steel is 80%

Solution

The microstructure given corresponds to the microstructure of a hypereutectoid steel.

Hypereutectoid alloys contain proeutectoid cementite (formed above the eutectoid temperature) plus pearlite that contains eutectoid ferrite and cementite.

Hypereutectoid corresponds to right of the eutectoid composition (0.76 wt % Carbon) i.e, compositions between 0.76 and 2.14 wt % Carbon.

So, Minimum carbon content = greater than 0.76 wt % Carbon (eutectoid composition)