What is iron carbon diagram?

A diagram based on the different percentages of carbon and iron. It shows the different grain structure in the materials created and different melting and "mushy" stages of the material at certain temperatures. Here is one: http://www.sv.vt.edu/classes/MSE2094_NoteBook/96ClassProj/examples/kimcon.html The metastable iron-carbon phase diagram, however, is used when studying the microstructures of steels (both carbon steels and alloy steels), as well as various heat treatments. Here is a detailed description of the metastable iron-carbon phase diagram: http://www.calphad.com/iron-carbon.html