Physical Metallurgy of Cast Irons

1. Fe-C system. Stable and metastable equilibrium diagrams.

1.1. Fe-C equilibrium diagram.

1.2. Graphitizing elements.

1.3. Inoculant elements.

1.4. Carburigenous elements.

1.5. The influence of silicon in cast irons.

2. Stable eutectic. Graphite morphologies.

2.1. Stable eutectic.

2.2. Lamellar graphite morphologies.

3. Compromise between stable and metastable solidifications.

3.1 Composition and massivity factor (section sensivity or volume/area ratio).

3.2. Superheating.

3.3. A eutectic of iron phosphide (Fe₃P), steadite.

4. Stable and metastable cooling compromise in solid state.

4.1. Introduction.

4.2. Cooling of gray cast irons in solid state: matrix structures.

4.3. Non-equilibrium transformations. Low and medium alloy elements.

4.4. High alloying and transformations during the cooling.

4.5. Transformations by heating.

4.5.1. Indirect ferritizing due to heat treatment.

4.5.2. Cementite graphitization at 450 °C.

5. General properties of non-alloyed gray cast irons (or low alloy) and flake graphite.

6. Malleable irons.

6.1. Malleable cast irons.

6.2. White heart malleable cast iron.

6.3. Blackheart malleable cast iron.

6.3.1. Ferritic blackheart malleable cast iron.

6.3.2. Blackheart malleable cast iron of pearlitic matrix.

7. Spheroidal graphite cast irons (or ductile cast iron).

7.1. Chemical composition.

7.2. General properties of ductile cast irons.

7.3.1. Ferritizing treatments.

7.3.2. Heat treatments for pearlitic matrix.

7.3.3. Treatments for achieving a matrix of tempered martensite.

7.3.4. Other treatments for austenitic cast irons: stress relieving

and hyperquenching.

7.4. Isothermal treatments. Austempered cast irons, ADI.

(Austempered Ductile Iron).

8. Fe-C-Cr system.

8.1. Binary diagrams.

8.3. Austenite with chromium. Composition limits and temperature.

8.3.1. Gamma iron constituents in the Fe-Cr system.

8.3.2. Limits of the gamma iron constituent in the Fe-C-Cr diagram.

9. Composition, structure, and properties of high alloy cast irons.

9.1. Introduction to high alloy cast irons.

9.1.1. Non-alloyed white cast irons.

9.2. High alloy cast irons for wear resistance applications.

9.2.1. Ni-hard cast irons.

9.2.2. Martensitic cast irons and K_C carbides eutectic (15-28% Cr).

9.3. Corrosion resistant cast irons.

9.3.1. High silicon cast irons.

9.3.2. Ferritic cast irons with more than 28% chromium.

9.3.3. High nickel cast irons (15-35% Ni).

9.4. Heat resistant cast irons.

10. Exercises, problems, and case studies.

10.0. Introduction.

10.1. Thermal analysis. Carbon solubility in the metastable and stable system.

10.2. Thermodynamics of the Fe-C-Si ternary system. Interaction coefficients. Carburigen and graphitizing elements.

10.4. Solidification times. Chvorinov equation.

10.5. Risering. Equations of Caine and Adams-Taylor. Exothermic isolation. Solidification defects.

10.5.1. Introduction to Caine's equation.

10.5.2. Risering in gray irons.

10.5.3. Rail aluminothermic welding (Applicable to exothermic risers).

10.5.4. Gases in cast metals.

10.5.5. Pressure tightness.

10.6. Mold filling times. Gating design. Down-hill casting and bottom casting.

10.6.1. Aspiration of gases.

10.7. Superheating. Fluidity. Castability.

10.8. Mechanical properties. Reliability (Weibull statistics).

10.9. Creep: stress relieving.

10.9.1. Measurement of residual stresses.

10.9.2. Stress relieving.

10.10. Thermal shock resistance. Damping capacity.

10.10.1. Thermal shock resistance.

10.10.2. Damping effect.

10.11. Fatigue.

10.12. Heat treatments.

10.13. Fe-C-Cr system.

Case study 1: CAM CAD methods applied to the feeding system of parts manufactured in Ni-hard cast iron.

Case study 2 and case study 3. Relationship structure mechanical properties in camshafts and crankshafts manufactured in cast iron.

Case study 2. Relation structure-mechanical properties of camshafts manufactured in cast iron.

Case study 3. Relation structure-properties in crankshafts manufactured in forged steel and spheroidal cast iron.

11. Fundamentals of the cupola furnace. Applications. Mass and energy balances.

11.1. Cast iron production in cupola furnace.

11.2. Sulfur and phosphorus in the cupola furnace.