Fe - Fe3C Eutectoidic Diagram

Annotations:

• Steel contains <2.1% carbon. Different carbon percentages completely change the structure and mechanical properties of iron.

1. Austenite (YFe)

   Annotations:

   • Heat YFe to temperature <750'C, and keep there long enough for solid mix to be homogeneous, to produce Austenite.
   1. Rapid cooling produces Martensite

      Annotations:

      • High Hardness, Too brittle to use
      1. Reheat for a few hours to Tempered Martensite
   2. Moderate cooling produces Bainite
   3. Slow cooling produces Pearlite

      Annotations:

      • Made up of cementite and ferrite mix
      1. Spheroidite

         Annotations:

         • Reheat Bainite or Pearlite to 700'C and keep at this constant temperature for 24hrs.