Composition: 3.52C-2.51Si-0.49Mn-0.2P-0.02S-0.06Mg (Carbon equivalent = 4.36).

Processing: Casting, Annealing (910ºC-2h), Normalizing.

Etching: 10-30s immersion in 2% nital.

This is the same cast iron as the one in F8 specimen, but with a normalizing heat treatment. During this treatment, Fe₃C dissolves and a structure consisting of austenite and spheroidal graphite is produced. Upon cooling in air, the eutectoid transformation predicted by the metastable diagram occurs (γ → α + Fe₃C). This results in a fine pearlite matrix with several graphite nodules. Due to the oxidizing atmosphere during treatment, there is some decarburization of the surface, resulting a ferritic matrix.

Fe-C diagram

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