1Since the FeC equilibrium phase diagram represents both the

1.Since the Fe-C equilibrium phase diagram represents both the family of steel and
iron, what distinguishes these 2 regions?

2. What is the most characteristic feature of the steel vs the iron portion of the phase
diagram? How is this characteristic used in the fabrication of steel vs iron components?

Solution

The percentage of carbon distinguishes betwen steel and iron in iron carbon diagram.

The steel part of the Fe-C phase diagram covers the range between 0 and 2.08 wt. % C. The cast iron part of the Fe-C phase diagram covers the range between 2.08 and 6.67 wt. % C.

The steel portion of the metastable Fe-C phase diagram is subdivided into three regions: hypoeutectoid (0 < wt. % C < 0.68 wt. %), eutectoid (C = 0.68 wt. %), and hypereutectoid(0.68 < wt. % C < 2.08 wt. %)..

liquid iron can dissolve C at levels well above 2.1 % C, solid iron cannot. This leads to a different solid structure for cast irons (iron with total C greater 2.1 %).