1.0 FERROUS MATERIALS.pdf easy to learn and understand

In this presentation you will find the properties of ferrous materials easily

1. ME 2207
ENGINEERING METALLURGY
Md Abdullah Al Mohotadi
Lecturer
Department of Mechanical Engineering,
BAUST, Saidpur
FERROUS MATERIALS

2. References
Department of Mechanical Engineering, BAUST
For my part of syllabus-
•Materials and Metallurgy –V.K. Manchand& G.B.S. Narang
•Engineering Metallurgy –R.A. Higgins
•Any books on the prescribed topics
•Various online resources mentioned in the classes

3. Department of Mechanical Engineering, BAUST
-Ferrous Materials-
Cast Iron

4. Chapter outcome
Department of Mechanical Engineering, BAUST
At the end of this chapter you should be learn about:
•Production of iron from iron ore
•Different types cast irons and their characteristics
•Application of each type ferrous materials
•Effect of Carbon and various alloy elements on cast iron

5. Department of Mechanical Engineering, BAUST
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6. Department of Mechanical Engineering, BAUST

7. Department of Mechanical Engineering, BAUST

8. Department of Mechanical Engineering, BAUST

9. Ferrous Materials
Department of Mechanical Engineering, BAUST
•Ferrous metals are those metals that
contain Iron.
•Ferrous products may broadly classified
as:
–Pig iron
–Cast iron
–Steel
–Wrought iron

10. Iron Ores
Department of Mechanical Engineering, BAUST
•Hematite Fe
2O
3 (70%)
•Limonite Fe
2O
3.3H
2O (60-65%)
•MagnetiteFe
3O
4 (72%)
•Siderite FeCO
3 (48.3%)
•Iron pyriteFeS
2 (46.6%)
•Copper pyrite CuFeS
2

11. World Mine Production and Reserves
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From wiki

12. World Steel Industry –Top Ten
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13. World Steel Industry –Top Ten
Department of Mechanical Engineering, BAUST

14. World Steel Industry –Top Ten
Department of Mechanical Engineering, BAUST

15. Iron production from ore
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•Iron is extracted from iron ores……..
•The iron ores contain certain percentages of
metallic ironand impurities. Sulfur, phosphorous,
silica and clay are the principal impurities.
•Materials used to produce pig iron are coke,
limestone and iron ore.
•All iron producedin blast furnaceswhether in
molten state or cast into pigs is known as pig iron.
•Pure iron is a soft metal having a structure of iron
crystals. Inmetallurgy, pure iron is called “Ferrite”

16. Blast Furnace –Components (1/2)
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►Cylindrical Steel Shell Lined With Refractory
►Nonmetallic Substance –Firebrick
►Approximately 30m High, 6-8 m dia.
►Shell Is Tapered At Top & Bottom
►Creates Nozzle Effect
►Lower Portion Is Called Bosh
►Tubular Openings Called Tuyeres-Hot Air Blast
►Holes At Bottom Are Tapped
►Upper –Slag
►Lower -Molten Pig Iron To Torpedo

17. Blast Furnace –Components (2/2)
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►Top Portion Lets Gases Escape (Vent)
►Hoppers
►Charge Is Introduced Through Bell-Shaped Valves
►Charge
►Mixture Of Iron Ore, Coke, & Limestone
►Hot Air Stoves
►Produce Hot Air
►Dump Cars Or Skips
►Deliver Charge To Hopper

18. Typical Blast Furnace

20. Blast Furnace –Operation
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˃Operate continuously
˃Small charges are introduced at 10-15 minutes
˃Spontaneous combustion of charge
˃Slag is tapped every 2 hours
˃Molten iron tapped five times a day
˃Hot air enters at 500-700
o
C

21. Reactions
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Coke→ provides the heat & supplies carbon (C) to
extract iron(25%)
Limestoneis used to reduce the impurities (15%)
1.C + O
2→ CO
2
2. CaCO
3→ CaO+CO
2
3. CO
2+ C → 2CO 1500 C
Reduction
4. 3CO + Fe
2O
3→ 2Fe + 3CO
2 start from 600 C
Slag formation
5. CaO+ SiO→ CaSiO
3 800-1000 C

22. Pig Iron composition
Department of Mechanical Engineering, BAUST
•As Produced From Blast Furnace, Contains
–Iron, 92%
–Carbon, 3 To 4%
–Silicon, 0.5 To 3%
–Manganese, 0.25 To 2.5%
–Phosphorous, 0.04 To 2%
–Sulfur, Trace Amounts

23. Cast iron
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Castironisageneraltermappliedtoawiderangeofiron-
carbon-siliconalloysincombinationwithsmallerpercentageof
severalotherelements.
Castironismadewhenpigironisre-meltedinasmallcupola
furnaces(similartotheblastfurnaceindesignandoperation)
andpouredintomoldstomakecastings.CastIronisgenerally
definedasanalloyofIronwithgreaterthan2%Carbon,and
usuallywithmorethan0.1%Silicon.
Duringtheremeltingoperationinthecupola,noparticular
chemicalchangeintheironisexpected.Someoftheimpurities
maybeeliminatedandamoreuniformproductisobtained.

24. Cast Iron
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Iron with 1.7 to 4.5% carbon and 0.5 to 3% silicon
Lower melting point and more fluid than steel (better
castability)
Good wear resistance and good machinability
Low cost material usually produced by sand casting
A wide range of properties, depending on composition &
cooling rate
–Strength
–Hardness
–Ductility
–Thermal conductivity
–Damping capacity

25. Iron Carbon Diagram
Department of Mechanical Engineering, BAUST
Liquid
Austenite
a + Fe
3C
d
g+ L
a+ g
L + Fe
3C
723˚C
910˚C
0% 0.8% ~2% ~3%
a
g+ Fe
3C
Cast Iron
Carbon
Steel
%C

26. Types of Cast Iron
Department of Mechanical Engineering, BAUST
•Graycast iron -carbon as graphite
•White cast iron -carbides, often alloyed
•Ductile cast iron
–nodular, spheroidal graphite
•Malleable cast iron

27. Application of Cast Iron
Department of Mechanical Engineering, BAUST
•Engines
•Cylinder blocks, liners,
•Brake drums, clutch
plates
•Pressure pipe fittings
(AS2544)
•Machinery beds
•Furnace parts, ingot and
glass moulds
•Pipe and pipe fittings
•Kitchen utensils
The Iron Bridgeover theRiver Severnat Coalbrookdale,
England (finished 1779)

28. Gray Cast Iron
Department of Mechanical Engineering, BAUST
•When cast iron is allowed to cool slowly, most of the free
carbon solidifies in large crystals known as graphite.
•A small part of the carbon combines
with iron to form cementite (Fe
3C).
Iron and Carbon unit to form Iron
Carbide (Fe
3C) “Cementite” withthe
ratio of 1 Carbon : 14 Iron.
•Cementite: is very hard and brittle
substance so the more cementitethe
ironcontains the more it gets harder.

29. Microstructure of gray
cast iron
Separate graphite
flakes form
X500X100

30. Gray Cast Iron –Composition
Department of Mechanical Engineering, BAUST
•Typical composition
–C: 3 -3.75%
–Si: 1 -2.75%
–Mn: 0.4 –1%
–P: 0.15 –1%
–S: 0.06 –0.15%
Remainder Iron

31. Gray Cast Iron -Properties
Department of Mechanical Engineering, BAUST
•The strength of grayiron depends on the strength of steel
matrix and the size and character of graphite flakes in it
•Low ductility -elongation 0.6%
•Graphite flakes act as stress raiser at their sharp tips making
the gray iron brittle in tension
•High compressive strength
•High fluidity and able to make good casting because of low
shrinkage during solidification
•Good resistance to rust or corrosion
•Better machinability than steel
•Good damping, less vibration

32. Relativeabilityofferrousmetalstodampen
vibrations.Theenergyabsorbedpercycle,orspecific
dampingcapacityofthesecandifferbymorethan10
times.
Great at dampening!

33. Gray Cast Iron-Application
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•Flywheels
•Automobile cylinders and
pistons
•Gears
•Brake wheels
•Manhole covers
•Pulleys
•Machine frames
•Pressure valves
•Water main pipes
•Soil pipes , etc

34. Effect of composition
Department of Mechanical Engineering, BAUST 3
equivalentCarbon
Si
CCE 
•A CE over 4.3 (hypereutectic) leads to carbide or graphite
solidifying first & promotes graycast iron
•A CE less than 4.3 (hypoeutectic) leads to austenite
solidifying first & promotes white iron

35. ©2010 John Wiley & Sons, Inc.
M P Groover, Principles of
Modern Manufacturing4/e SI
Version
Ductility
•Ability of a material to plastically strain without
fracture
•Ductility measure = elongation EL
where EL= elongation; L
f= specimen length at fracture; and L
o= original
specimen length
L
f is measured as the distance between gage marks after two pieces of
specimen are put back togethero
of
L
LL
EL



36. • Plastic tensile strain at failure:
Adapted from Fig. 6.13,
Callister 7e.
Ductility
• Another ductility measure: 100x
A
AA
RA%
o
fo
-
=
x 100
L
LL
EL%
o
of


Engineering tensile strain, e
Engineering
tensile
stress, s
smaller %EL
larger %EL
L
f
A
o
A
f
L
o
Is rubber ductile ?

37. Malleability
•Uni-direction plastic deformation
•Drawn into wires
•Deform under pressure/stress
Ductility
•All-direction plastic deformation
•Beaten into sheet
•Deform under pressure/stress

38. Strength
•Fracture resistance
•Amount of force necessary for a material to deform
•Internal property
Adapted from Fig. 6.11,
Callister 7e.
s
y
strain
Typical response of a metal
F= fracture or
ultimate
strength
Neck –acts
as stress
concentrator
engineering
TS
stress
engineering strain
• TS is Maximum stress on engineeringstress-strain curve.

39. Plastic means permanent!
Plastic Deformation (Metals)
F
d
linear
elastic
linear
elastic
dplastic
1. Initial2. Small load 3. Unload
planes
still
sheared
F
delastic + plastic
bonds
stretch
& planes
shear
dplastic

40. • Energy to break a unit volume of material
• Approximate by the area under the stress-strain
curve.
Toughness
Brittle fracture: elastic energy
Ductile fracture: elastic + plastic energy
very small toughness
(unreinforced polymers)
Engineering tensile strain, e
Engineering
tensile
stress, s
small toughness (ceramics)
large toughness (metals)
Adapted from Fig. 6.13,
Callister 7e.

41. Hardness
• Resistance to permanently (plastically) indenting the surface of a product.
• Large hardness means:
--resistance to plastic deformation or cracking in compression.
--better wear properties.
e.g.,
Hardened 10
mm sphere
apply known force
measure size
of indentation after
removing load
dD
Smaller indents
mean larger
hardness.
increasing hardness
most
plastics
brasses
Al alloys
easy to machine
steels file hard
cutting
tools
nitrided
steelsdiamond
Hardness essentially measures the force required to deform the molecules. From a
molecular standpoint, it is how much free space there is in the crystal lattice that
can be compressed for a relatively small energetic cost.

42. White Cast Iron
Department of Mechanical Engineering, BAUST
•Whencastironisnotallowedtocoolslowly,the
amountofcementiteincreasesandtheamountof
graphitedecreases.
•MostcarbonisreactedwithFeto
getcementite(Fe
3C).
•Therefore,whitecastironisstrong
andhardbutbrittle.
•Duetotheabsenceofgraphite,it
hasalightappearance

43. Microstructure
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44. White Cast Iron -Compositions
Department of Mechanical Engineering, BAUST
•Typical composition
–C: 2 -2.5%
–Si: 0.85 –1.2%
–Mn< 0.4 %
–P< 0.2%
–S< 0.12%
Remainder Iron

45. White Cast Iron -Properties
Department of Mechanical Engineering, BAUST
•The presence of different carbides, depending on alloy
content, makes white cast irons extremely hard and but
very brittle.
•Excellent abrasive wear resistance
•Difficult to machine
•Poor weldabilitybut good castability
•Often alloyed to make malleable cast iron

46. White Cast Iron-Application
Department of Mechanical Engineering, BAUST
•Producing malleable cast iron
•Manufacturing those
components part which
require a hard and abrasion
resistance material-
–Stairs
–Tools and utensil
–Decorative pieces
–Bearing surface

47. Cast Iron –Carbon -Silicon diagram
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48. Ductile Cast Iron
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•SmallquantitiesofMg(modifier)addedtothe
desulphurisedmelttoproducethisiron
•Thebasiccompositionofthemeltis3-4%Cand
2.5%Si
•ThefairlyhighSiequivalentproducesgraphitisation
duringsolidification.
•Themodifierhastheeffectofmakingthegrowth
rateofgraphitesameinalldirections,sothata
sphericalshaperesults
•KnownasDuctile/nodular/spheroidalgraphite(SG)
castiron

49. Ductile Cast Iron
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Separate graphite
flakes form
Mg added to molten iron –helps
spherodisegraphite
Low levels of minor elements
such as S and P
X100
X500
X100

50. Ductile Cast Iron
Department of Mechanical Engineering, BAUST
•Nodular iron is a major engineering material,
as it combines the advantages of steel with
the processing economies of iron
•Good tensile strength with elongation in the
range 6-18%
•Strength higher than gray cast iron

51. Ductile Cast Iron –Application
Department of Mechanical Engineering, BAUST
•Automobile industry are
the major user of ductile
cast iron
–crankshafts
–gears etc.
•Water pipes and pipe
fittings

52. THANK YOU
Special Thanks to:
Dr. Md. Abdullah Al Bari
Assistant Professor
Department of Mechanical Engineering,
Khulna University of Engineering and Technology (KUET)