1. SOLIDIFICATION OF 0.05%C STEEL 1.Liquid with 0.05%C to δ +L 2. L + δ to δ 3 BCC δ cools with C% change 4 δ to δ + Austenite,FCC 5 δ + Austenite to Pure Austenite, FCC 6. FCC Austenite 7

2. Location near EUTECTOID Region 0.8% C FERRITE α +γ γ FERRITE + CEMENTITE δ Iron - BCC – Max. solubility of 0.1% at 1493 0 C γ Iron – FCC – AUSTENITE- max. solubility of 2% at 1131 0 C α Iron – BCC- max. solubility of 0.02% at 723 0 C – FERRITE Fe 3 C –CEMENTITE - 100% iron carbide - Intermetallic Compound - From Latin caementum, meaning stone chips. –

3. 723 0 C 910 0 C

4. PEARLITE

5. 7. Austenite to Ferrite + Austenite 8. Austenite in (7) to Pure Ferrite ( α) + Eutectoid ( α +Fe 3 C) 9. Ferrite to stable form with C% decrease + Pearlite 10. At room condition, C% in Ferrite is only 0.0025%

6. BCC Tetragonal based cell on ABCD and FCC Austenite

7. Unit cells AusteniteFerriteMartensite FCC BCC RECT.PRISM- BC Tetragonal