N.G. PATEL POLYTECHNICN.G. PATEL POLYTECHNICIsroli - AfwaIsroli - Afwa

GUIDED BY :-

MR. N.N.PATELMR. S.R.PATEL

PREPARE BY:-ABHI D. PANWALA 106370319074KRUNAL S. PATEL 106370319087DEVEN K. PRAJAPATI 106370319083

Seminar On

IRON-CARBON EQULIBRIUM DIAGRAM

INDEX

• PURPOSE• IMPORTANT TERMS• FIGURE ANALYSIS• USES• LIMITATIONS

PURPOSE• TO UNDERSTAND :-- Ferrous metallurgy easily.- Necessity Heat treatment process.- Effects of alloying elements.- Properties of steel.- Changes occurred in iron by varying

carbon percentage.- Structures of steel.

IMPORTANT TERMS

Austenite

• γ- iron• FCC structure• 2% carbon maximum.• Non magnetic and tough.• Solidifies around temperature 113 c.0̊ ̊ 0̊� ̊�

• α- iron.• Less than 0.025% carbon• BCC structure• Hardness 50-100 BHN• 3400 kgf/cm^2 strength.

Ferrite

Pearlite

• Combination of ferrite and cementite.

• 0.8% carbon.• Hardness 180 BHN.• Strenght 9400kgf/cm^2.• Appears like mother of

pearl.

Cementite• Contains carbon around

6.67%.• Hardness 650 BHN.• Strength 450 kgf/cm^2.• Brittle and white in

colour.• Can be magnetised.

Ledeburite

• Contains 4.3% carbon.• Some what hard.• Form of decompose

eutectic.• Exists around 1147 c. ̊�

Other terms• Eutectoid – The metal formed at 723 c containing ̊�

0.85% carbon is known as eutectoid.• Steel – Iron containing upto 0 to 2% is known as steel.

• Eutectoid steel – The steel having 0.8% carbon and in the form of 100% pearlite is known as eutectoid steel.

• Hypo Eutectoid steel – The steel having carbon less then 0.8% is known as eutectoid steel.

• Hyper Eutectoid steel – The steel having carbon from 0.8% to 2% is known as Hyper Eutectoid steel .

• Eutectic – The metal formed at 1130 c ̊�containing 4.3% carbon is known as eutectic.

• Cast iron – Iron containing carbon more than 2% is known as cast iron.

• Hypo Eutectic C.I – The C.I containing 2 to 4.3% carbon is known as Hypo Eutectic C.I .

• Hyper Eutectic C.I - The C.I containing 4.3 to 6.67% carbon is known as Hypo Eutectic C.I .

IRON-CARBON EQULIBRIUM DIAGRAM

FIGURE ̊ANALYSIS• There are three types of iron forming in

process α, δ, γ.• α – ferrite form, magnetic material, BCC

structure.• γ – austenite form, non magnetic, FCC

structure.• δ – BCC structure.

Iron

Steel Cast iron

• Steel – contains 0.008 to 1.8% carbon. Types – hypo eutectoid - hypereutectoid• Cast Iron – contains 1.8 to 6.67% carbon. Types – hypoeutectic - hypereutectic

• Pure molten iron solidify at 1539 c. ̊�• When 2 to 4% carbon is added in iron its solidification

temperature comes down to 1130 c. ̊�• When it is under range of 2% then it is hypereutectoid

steel and if above 2-4% then it is hypoeutectic .• If we increase more carbon % then it forms cementite,

upto 6.67%.• Austenite does not contain carbon more than 0.025%.• When it is in range between 0.025 to 0.08% then it is

ferrite.• When temperature is in range upto 723 c and carbon is ̊�

more then 1.7% with alloys then it is ledeburite.• Pearlite is form with two structures of ferrite and

austenite.

Uses ̊• Predict number type and composition of

phases.• Predict amount if phases.• Guide heat treater.• Predict micro-structure of alloy.

LIMITATIONS• we cannot get the exact temperature at

which they get solidify , we only get temperature range.

• It does not give information about size of micro-structure.

• It does not give information about physical properties of materials.

• It does not give detail information about how transformation of phase take place.

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