1. CHAPTER 2 :
FERROUS MATERIAL
STRUCTURE AND BINARY
ALLOY SYSTEM

2. METAL PRODUCTION
IRON PRODUCTION

3. INTRODUCTION TO IRON
 Pure iron is soft (softer than aluminium), but is
unobtainable by smelting.
 Iron is significantly hardened and strengthened
by impurities from the smelting process, such
as carbon.
 Crude iron metal is produced in blast furnaces,
where ore is reduced by coke to cast iron.

4. Types of Iron Ore
Iron
Limonite Magnetite Hematite
Carbonate

5. IRON ORE CONTENT
 LIMONITE
Content : 20% - 55% irons + 40% water
Colour : Yellow brownish

6.  IRON CARBONATE
Content : Less than 30% irons + Carbon +
Phosphorous
Colour : Grey

7.  MAGNETITE
Content : 72.4% irons
Colour : Black

8.  HEMATITE
Content : 40% - 65% irons
Colour : Dark brown reddish

9. BLAST FURNACE
 What is the purpose of Blast Furnace?
Is to chemically reduce and convert iron ores
into liquid iron called "hot metal". This is due to
Iron ore contains impurities, mainly silica
(silicon dioxide).
 Basic material for iron production :
Iron ore, limestone, and coke.

10.  Blast Furnace diagram :

11.  The Exhaust Gas Outlet
To expel used gases
 Charging Bells
Have two bells; small and big. To allow the
Charge drop into the Furnace.
 Gas Outlet
Holes in the Furnace that allows the escaping
gases to get to the Exhaust Gas Outlet.

12.  Tuyere
These are small pipes that permit hot air to
enter the furnace.
 Taphole
Used to draw off the molten Iron.
 Slag Hole
Used to draw off the waste Slag.

13.  Refractory Lining
Reflects the heat into the Furnace.
 Conveyor System
Takes the Charge to the top of the Blast
Furnace. The Charge is carried in Skip Cars
which run on a rail track.

14.  Process in blast furnace
- Iron ore, coke and limestone are carried to the
top of the blast furnace and dumped into it.
- Limestone is added to the blast furnace to
remove the impurities in the iron ore.
- Limestone reacts with the silica to form molten
slag in the blast furnace.
- Slag flows to the bottom of the furnace where
it floats on the liquid iron and is easily
removed.

15. - Hot air is blasted into the furnace causing coke
to burn rapidly and raise the temperature to
2000°C.
carbon+ oxygen = carbon dioxide + heat.
- The carbon dioxide then reacts with hot
carbon to form carbon monoxide which
reduces iron in the ore to iron metal.
- Iron falls to the bottom of the furnace and is
tapped off periodically.

16. STEEL PRODUCTION

17. INTRODUCTION TO STEEL
 Is an alloy consisting of a certain proportion of
carbon (between 0.2% and 2.1%) and iron.
 Steel is 1000 times harder than pure iron.
 Further refinement with oxygen reduces the
carbon content in cast iron from blast furnace
process produce steel.

18. BASIC OXYGEN FURNACE
(BOP)
 What is the process of Basic Oxygen Furnace
(BOF)?
Is a steel making furnace, in which molten pig
iron and steel scrap convert into steel due to
oxidizing action of oxygen blown into the melt
under a basic slag.

19.  BOF Diagram

20.  The Water-Cooled Oxygen Lance
Provides the oxygen to the furnace so that the
temperature in the furnace will increase.
 The Slagging Hole
Where the slag can be poured out when
necessary.
 The Steel Shell

21.  The Refractory Lining
Has two purposes. The first is to keep the heat
from the furnace. The second reason is to
protect the Steel Shell of the Furnace.
 The Tapping Hole
Used to remove the Molten Steel from the
Furnace.

22.  The Gas Offtake Hood
Has two purposes.
i) To trap the dangerous gases that the BOF
produces so that they cannot escape into the
atmosphere. One important use of the gases is
to heat the Oxygen that is going through the
Water-Cooled Oxygen Lance.
ii) To reduce the amount of heat loss in the
Furnace.

23.  Process in BOF
The furnace is tilt and charge it with scrap.

24. Hot iron metal from the blast furnace is
poured from a ladle into the top of the
tilted furnace.

25. The charged furnace is returned to an upright position and
a water cooled oxygen lance is lowered from the top;
oxygen is blown at supersonic speeds causing rapid
mixing and heat from the oxidation of iron and impurities.
Fluxes are added to help carry off the impurities in the

26. After the steel has been refined, the furnace is
tilted (opposite to the charging side) and molten
steel is poured out into a preheated ladle.

27. ELECTRIC ARC FURNACE
 What is the process of Electric Arc Furnace??
Is a steel making furnace, in which steel scrap
is heated and melted by heat of electric arcs
striking between the furnace electrodes and
the metal bath.

28.  Electric Arc Furnace Diagram

30.  Scrap Charge
- Steel scrap is tipped into the EAF.
- Electrodes then are lowered into the furnace.
- An electric current is passed through the
electrodes to form an arc.
- The heat generated by this arc melts the
scrap.

31.  Melting Phase
- During the melting process, other metals
(sulphur) are added to the steel to give it the
required chemical composition.
- Oxygen is blown in to the furnace to purify
the steel.
- Limestone and fluorspar are added to
combine with the impurities and form slag.

32.  Tap out
- The furnace is tilted to allow the slag, which
is floating on the surface of the molten steel, to
be poured off.
- The furnace is then tilted in the other
direction and the molten steel poured (tapped)
into a ladle.

33. PLAIN CARBON STEEL

34. INTRODUCTION
 Plain carbon steel is a type of steel having a
carbon content may range from less than
0.02% to slightly more than 2%.

35. IRON-CARBON PHASE
DIAGRAM

37.  The eutectoid reaction describes the phase
transformation of one solid into two different
solids.
 In the Fe-C system, there is a eutectoid point
at approximately 0.8wt% C, 723°C.
 The phase just above the eutectoid
temperature for plain carbon steels is known
as austenite or gamma.

39.  The compositions of the two new phases are
given by the ends of the tie-line through the
eutectoid point.
 The general eutectoid reaction is therefore:
Solid γ –> solid α + solid β
 Or using the names given to these phases:
Austenite –> ferrite + cementite (Fe3C)

40.  ASSIGNMENT
i) Sketch an iron-carbon phase diagram up to
2% C & at 910ºC together with the
microstructure for various phases of steel.
ii) Create your own style how to remember
every phase in the iron-carbon phase diagram.
Submit the assignment by 2nd October 2011.

41.  Ferrite (α)
- Also known as alpha iron.
- Is an interstitial solid solution of a small
amount of carbon dissolved in iron with a Body
Centered Cubic (B.C.C.) crystal structure.

42.  Austenite (γ)
- Also known as gamma-iron,
- Is an interstitial solid solution of carbon
dissolved in iron with a face centered cubic
crystal (F.C.C) structure.

43.  Cementite (Fe3C)
- Is also known as iron carbide which has a
chemical formula, Fe3C.
- It contains 6.67 % Carbon by weight.
- Its crystal structure is orthorhombic.

44.  Pearlite
- It is the eutectoid mixture containing 0.83 %
Carbon and is formed at 1333oF on very slow
cooling.
- It is very fine platelike or lamellar mixture of
ferrite and cementite.
- The structure of pearlite includes a white
matrix (ferritic background) which includes thin
plates of cementite.

45.  Ledeburite (a + Fe3C)
- It is the eutectic mixture of austenite and
cementite.
- It contains 4.3 % Carbon and represents the
eutectic of cast iron.
- Ledeburite exists when the carbon content is
greater than 2 %, which represents the
dividing line on the equilibrium diagram
between steel and cast iron.

46. ALLOY STEEL

47. DEFINITION
Alloy steel is a steel which contains more
than 1% of other elements besides carbon
and iron.

48. PURPOSE
To improve quality and steel properties so that it
can easily be modify by heat treatment.

49. ELEMENTS INFLUENCE
Manganese improves hardenability, ductility and wear resistance.
(Mn) Mn, increasing strength at high temperatures.
Copper (Cu) improves corrosion resistance.
Chromium (Cr) improves hardenability, strength and wear resistance,
sharply increases corrosion resistance at high
concentrations (> 12%).
Sulfur improves machinability.
Silicon (Si) improves strength, elasticity, acid resistance and
promotes large grain sizes, which cause increasing
magnetic permeability.
Nickel (Ni) increases strength, impact strength and toughness,
impart corrosion resistance in combination with other
elements.
Molybdenum increases hardenability and strength particularly at high

50. Aluminum deoxidizer, limits austenite grains growth.
(Al)
Vanadium increases strength, hardness, creep resistance and
(V) impact resistance due to formation of hard vanadium
carbides, limits grain size.
Tungsten increases hardness particularly at elevated
(W) temperatures due to stable carbides, refines grain size
Titanium improves strength and corrosion resistance, limits
(Ti) austenite grain size.

51. TYPES OF ALLOY STEELS
3 TYPES
MEDIUM
LOW ALLOY HIGH ALLOY
ALLOY
STEELS STEELS
STEELS

52.  STRUCTURE STEEL
 CORROSION RESISTANCE STEEL
 HEAT RESISTANCE STEEL
 TOOL & MOULD STEEL
 MAGNETIC STEEL

53. Structure Steel
o Element Content : Ni, Mn, Cr, Mo
o Properties : High strength
o Usage : for construction purpose.

54. Corrosion Resistance Steel
o Element Content : Cr, Ni, Mo, Ti
o Properties : corrosion resistance, high strength
and ductility.
o Usage : cutlery, health care and surgical
equipment, etc.

55. Heat Resistance Steel
 Element Content : 18% W + 4% Cr + 1% V +
0.88% C
 Properties : High strength and hardness, wear
resistance.
 Usage : Tool for cutting at high temperature
~660˚C.

56. Tool & Mould Steel
o Element Content : 0.6-1.5% C
o Properties : High strength, wear resistance at
elevated temperature.
o Usage : used in forming and machining of
metals.

57. Magnetic Steel
o Element Content : Depend on types of
magnetic steel to produce (permanent or
temporary).
o Properties : have magnetic field.
o Usage : Magnet

58. CAST IRON

59.  HOW CAST IRON BEEN MADE ???
Re-melting pig iron, steel scrap to cupola (small
blast furnace).

60. FACTORS INFLUENCE
PROPERTIES
ELEMENT
COOLING
CONTENT
RATE
4 FACTORS
CARBON
HEAT
CONTENT
TREATMENT

61. Cooling Rate
 Depend on thickness and type of mould.
High Cooling Rate Low Cooling Rate
Produce : Produce : Graphite
Cementite
White Cast iron Gray Cast Iron

62. Element Content
Element Function
Carbon Increase graphite content
Silicon Help formation of graphite
Sulfur + Stabilize cementite and
Manganese combination of sulfur and
manganese form manganese
sulfide.
Phosphorous Lower down melting point

63. Heat Treatment

64. TYPES OF CAST IRON
CAST IRON
GRAY CAST WHITE NODULAR MALLEABLE
RON CAST IRON CAST IRON CAST IRON

65. Gray cast iron
 Gray cast iron, named because its fracture has a gray
appearance
 Produce by slow cooling.
 Structure : Graphite in the form of flakes.
 Properties :
> Advantages : Self-lubricate.
> Disadvantages : Negligible ductility, weak in
tension.
 Usage : Gear box, head stock, bearing bracket.
Figure 1. Graphite Flakes in Figure 2. Photomicrograph of
Gray Cast iron Gray Cast iron

66. White cast iron
 Is called white cast iron because of the white crystalline
appearance of the fracture surface.
 Produce by rapid cooling.
 Structure : Iron carbide
 Properties :
> Advantages : Very hard (difficult to machine),
abrasion resistance.
> Disadvantages : Brittle.
o Usage : Extrusion dies, ball mills.
Figure 1. Photomicrograph of
White Cast Iron

67. Malleable cast iron
 Is called malleable cast iron because of latin words ‘malleus’
meaning ‘can be hammered’.
 Produce by annealing white cast iron at 900˚C for 50hrs.
 Structure : Graphite exists as clusters or rossetes.
 Properties :
> Advantages : High ductility, strength and shock
resistance.
> Disadvantages : NA
o Usage : Transmission gears, connecting rods.
Figure 1. Malleable Cast Iron

68. Nodular cast iron
 Is called nodular cast iron because of graphite is in a nodular or
spheroid form.
 Produce when gray cast iron with small amounts of magnesium
and cerium which nodulates the graphite.
 Structure : Graphite in a nodular form.
 Properties :
> Advantages : High strength and high ductility.
> Disadvantages : NA
 Usage : Piston, crankshaft.