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
Location near EUTECTOID Region 0.8% C FERRITE α +γ γ FERRITE + CEMENTITE δ Iron - BCC – Max. solubility of 0.1% at C γ Iron – FCC – AUSTENITE- max. solubility of 2% at C α Iron – BCC- max. solubility of 0.02% at C – FERRITE Fe 3 C –CEMENTITE - 100% iron carbide - Intermetallic Compound - From Latin caementum, meaning stone chips. –
723 0 C C
PEARLITE
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 %
BCC Tetragonal based cell on ABCD and FCC Austenite
Unit cells AusteniteFerriteMartensite FCC BCC RECT.PRISM- BC Tetragonal