TOPICS COVERED HEAT TREATMENT OF STEELS FERROUS, NON FERROUS AND THEIR ALLOYS This is used for polytechnic students and engineering students of mechanical engineering

1. CHAPTER-04
heat treatment of steel

2. HEAT TREATMENT OF STEEL: PROCESS OF CHANGING STRUCTURE
AND PROPERTIES OF METALS AND ALLOYS BY CONTROLLED
HEATING AND COOLING.
Stages of heat treatment:
1. Heating: steel is heated slowly to some pre-determined temperature.
2. Soaking: holding the metal at that temperature until structure becomes uniform.
3. Cooling: steel is cooled slowly upto room temperature.

3. PURPOSE OF HEAT TREATMENT
1. To improve machinability.
2. To relieve internal stresses.
3. To remove gases from castings.
4. To refine or change the grain structure.
5. To improve various mechanical and electrical properties.
6. To improve corrosion resistance.
7. To improve wear resistance.
8. To harden the surface.

4. DEFINITIONS
Critical rate of cooling: the minimum temperature of cooling at which austenite is
transformed into complete martensite.
Martensite: it is super saturated solution of carbon in α-iron which is very hard and
brittle and is a body central tetragonal structure.
Bainite: it is a mixture of ferrite and cementite. It is obtained by isothermal
decomposition of austenite at 350ºc-450ºc.
Sorbite: at high rate of cooling (600ºc) austenite is transformed into fine mixture of
ferrite and cementite. Its structure is weak but more ductile.
Troosite: at a very high rate of cooling (550ºc-500ºc) austenite is transformed to very
fine mixture of ferrite and cementite.

5. TRANSFORMATION IN STEEL DURING SLOW COOLING
• When molten metal is cooled structure of metal starts changing at upper critical temperature and the change is
completed when metal is cooled down to lower critical temperature.
• At T1 and T2, austenite structure of steel is converted into ferrite (0.008%C) and pearlite(0.8%C)
• At T3 and T4, austenite structure is completely converted into pearlite and cementite.

6. HEAT TREATMENT PROCESSES
1. Annealing: to soften the steel.
2. Normalising: to refine the structure.
3. Hardening: to increase the hardness.
4. Tempering: to eliminate brittleness in hardened steel.
5. Surface hardening: to eliminate retained austenite in marteniste
structure in hardened steel.

7. ANNEALING
• it is defined as a softening process consisting of heating the steel to a temperature at
or neat the critical point, holding there for a certain time and then allowing it t o cool
slowly in furnace.
• Grain structure is coarse.
Types of annealing:
1.Full annealing
2.Isothermal annealing
3.Process annealing or sub-critical annealing
4.Spheroidise annealing

8. FULL ANNEALING
 Heating the steel to austenite phase and then cooling slowly within a closed furnace by putting off the
heat supply.
 Heating the hypo-euctectoid steel to a temperature of 30ºc-50ºc above upper critical point and the
same amount above lower critical temperature for hyper-euctectoid steel.
 Holding at t his temperature for sufficient time and then slow cooling in the furnace.

9. ISOTHERMAL ANNEALING
 In this process steel is heated above UCT and held for sometime at this temperature to form austenite
and the suddenly cooled to a temperature of 50ºc-1000ºc below LCT.
 At this tempereature austenite is completely decomposed to form pearlite. And then steel is cooled in
still air.
 It is widely used in reducing the hardness of alloy steel and suitable only form small components.

10. PROCESS OR SUB-CRITICAL ANNEALING
• In this process steel is heated to a temperature of 600ºc-700ºc below LCT and
holding at this temperature for 2-4hrs and it is air-cooled.
• This type of process results in softening the steel.
• This method suitable for low carbon steels and mild steels.

11. SPHEROIDIZE ANNEALING
• In this process steel is heated to temperature 20ºc-40ºc below LCP and holding it for
prolonged time of 2-8hrs and then cooling slowly in a furnace.
• It improves machinability, toughness, ductility and reduces hardness, strength.
• This process is particularly used for hyper-euctectoid steel.

12. NORMALISING
• It is defined as the process of heating steel to above UCT 810ºc-930ºc and holding
for a short period and then allowing it to cool in still air at room temperature.
• It is mainly used for low and medium carbon steels and alloy steels.
• As the cooling rate is faster fine grain structure is formed.

13. HARDENING OR AUSTENING
In this process steel is heated to a temperature
within or above its critical range and held at that
temperature for a considerable time and then
allowed to cool by quenching in water, oil or
brine solution.
For hypo-euctectoid steels heated at 30ºc-50ºc
above UCT. For hyper-euctectoid steels heated
30ºc-50ºc above LCT.
On heating above critical temperature, the
structure becomes austenite and on rapid
cooling austenite changes into martensite.

14. TEMPERING
• It is the process of reheating the hardened steel to a temperature below critical range
followed by any rate of cooling.
• Types of tempering process:
1.low-temperature tempering: this type is performed at 250ºc and holding for 2-3hrs
and then cooled. And is employed to retain micro structure of martensite. Process is
used for making cutting tools, measuring tools.
2.Medium temperature tempering: this type is performed at 350ºc-500ºc and is cooled
in water. And is employed to retain martensite structure into troosite. Process is used
for making steel springs and die steels.
3.High temperature tempering: this type is performed at 500ºc-670ºc. And employed
for resultant steel structure called sorbite. Process is used for making gear wheels,
connecting rods and shafts.

15. AUSTEMPERING (ISOTHERMAL
QUENCHING):
the steel is heated to a temperature 50ºc-
100ºc above LCT and then quenched down
into a molten salt bath to a temperature of
300ºc. It is held at sufficient time to
decompose from austenite into bainite. This
method is applied for small components
made of high carbon steel or low-alloy steel.

16. MARTEMPERING
(STEPPED
QUENCHING):
the steel is heated above the
transformation range and then
suddenly quenched in molten salt
bath at temperature of 180ºc-
300ºc. Its main purpose is to
minimize distortion, cracking and
internal stresses.

17. Surface hardening
• The surface to be hardened is heated to austenite range and then quenched immediately to form martensite. This
process is employed to increase hardness, wear resistance.
• Methods of surface hardening:
1. Induction hardening
2. Flame hardening
Case hardening
• components like gear, cam shafts etc., require a hard wear resistance but at the same time they require tough,
ductile core to withstand shock loads. For these purposes case hardening is performed.
• Methods of case hardening:
1. Carburising
2. Nitriding
3. Cynaiding
4. carbonitriding

18. INDUCTION HARDENING
• The part to be surface hardened is placed within induction coil through which a high frequency current is passed.
This causes current to induce in that part and temperature is rised and is quenched immediately by a jet of cold
water.
• https://youtube.com/shorts/_AMLvRWZJ-8?feature=share

19. FLAME HARDENING
• The process consists of heating the work surface of medium and high carbon steel by oxy-acetylene flames at
2400ºc-3500ºc and cooled immediately in water or air blast.
• https://www.youtube.com/watch?v=yz9FradY_Co

20. CARBURISING
• It is to add carbon content in a metal surface. Its purpose is to obtain a hard layer on the surface of the workpiece.
It is mainly employed for low carbon steel.
• Types of carburising process:
1. Solid or Pack carburizing: the parts of low carbon steels are surrounded by carburizing mixture and packed in a
closed container. And is heated to a temperature of 810ºc-1100ºc and the time is 6- 8hrs.
2. Gas carburizing: in this process the work pieces are heated in a furnace in which the carburizing gas (which Is
rich in carbon) such as methane, propane or butane is circulated.

21. Nitriding
In this process the steel is heated
to a temperature of about 654ºc in
the presence of ammonia gas and
held there for a period of time.
Nitrogen liberated is combined
with iron to form iron nitride.
Applications: many automobile
parts, aero planes, pump shafts
and gauges.
Cyaniding
This process is generally used
for producing hard cases on low
and medium carbon steels. The
cyanide mixture of 20%-50%,
sodium cyanide and 40% of
sodium carbonate (soda ash)
with varying amounts of
sodium and barium chloride is
heated to a temperature of
870ºc-930ºc.
Carbonitriding
In this process mixture of
ammonia and hydro carbon gas
is used. The work is heated to
700ºc-900ºc. In the mixture of
above gases for 2-10hrs. This is
followed by quenching and then
tempering is employed at 180ºc.
Both carbon and nitrogen
diffuse simultaneously.

22. • If γ (Austenite) is super cooled below temperature
723ºc and is undergoes a transformation which is
plotted in time temperature diagram or c-curves or S-
curves.
• the metal is heated upto austenite temperature range
for sufficiently long period to assure complete
transformation to austenite then they are rapidly cool.
• No decomposition of austenite is observed during the
initial period of time which is called incubation
period. After this period, austenite begins to
decompose into ferrite and cementite mixture.

23. CHAPTER -05
Ferrous, non-ferrous metals and their alloys

24. CLASSIFICATION OF CAST IRON
1.Gray cast iron
2.Ductile cast iron or nodular cast iron or spheriodal cast iron.
3.White cast iron
4.Malleable cast Iron
5.Compacted graphite iron

25. GRAY CAST IRON
In gray cast iron graphite exists in largely in the form of flakes. It is called gray cast iron because the graphite flakes gives
the cast iron grey appearance when fractured.
Properties: 1. negligble ductility
2. Good damping capacity
3. Ability to dissipate enrgy
4. High compressive strength
5. moderately brittle
Applications: machine tools and supports for structures.
Composition: carbon: 3-3.6%
silicon: 2-2.5%
manganese: 0.15-0.6%
phosphorous: 0.025-0.04%
Sulphur: 0.015-0.04%
Iron: remaining

26. DUCTILE IRON (NODULAR IRON OR SPHEROIDAL GRAPHITE IRON)
In the ductile iron structure graphite is in a nodular or spheroid form. Graphite flakes is changed into nodules
(spheres) by adding magnesium and cerium to the molten metal. As graphite is present in the form of sphere, this
iron is called as spheroidal graphite iron.
Properties:
1. High fluidity
2. Excellent strength and ductility
Applications: used in hydraulic cylinders, valves, pipes and pipe fittings.
Composition:
Carbon: 3-3.6%
Silicon: 2-2.5%
Manganese: 0.15-0.6%
Phosphorous: 0.025-0.4%
Sulphur: 0.015-0.04%
Iron: remaining

27. WHITE CAST IRON
The white cast iron structure very hard because of the presence of large amounts of iron carbide (instead of
graphite). It is obtained by cooling gray iron rapidly or adjusting the composition by keeping the carbon and
silicon content low.
Properties:
1. Wear resistance
2. Brittle
Applications: grinding balls, extrusion dies and agricultural machinery.
Composition:
Carbon: 2.5%
Silicon: 1.5%
Manganese: 0.6%
Phosphorous: 0.15%
Sulphur: 0.5%
Iron: remaining

28. MALLEABLE IRON
• It is obtained by annealing white cast iron in an atmosphere between 800ºc and 900ºc for upto several hours.
Properties:
1. Promotes ductility
2. High tensile strength
3. High shock resistance
Applications: automotive and agricultural equipment industries, hinges, door-keys, spanners, cranks, levers.
Composition:
Carbon: 2.0-2.8%
Silicon: 0.7-1.4%
Manganese: 0.4-0.6%
Phosphorous: 0.2%
Sulphur: 0.1%
Iron: remaining

29. PLAIN CARBON STEELS
• Steel is the amin product of ferrous metallurgy with roughly 90% being
manufactured as carbon steel and 10% as alloy steel.
• Plain carbon steel is an alloy of iron and carbon.
Comuposition:
Carbon: 0.08-1.7%
Manganese: 0.3-1.0%
Silicon: 0.05-0.3%
Sulphur: 0.05%
Phosphorous: 0.05%

30. CLASSIFICATION OF PLAIN CARBON STEEL
• Low carbon steel: also called mild steel with less than 0.3% carbon. And is
generally used for common industrial products. Mild steel is further divided into
dead mild and mild steel.
Applications: bolts, nuts, sheet plate and tubes.
• Medium carbon steel: with 0.30-0.60% of carbon.
Applications: gear axles, connecting rod and crank shafts.
• High carbon steel: with more than 0.60% carbon. After being manufactured into
shapes these steels are usually heat treated and tempered.
Applications: cutting tools, music wires, springs.

31. CLASSIFICATION OF PLAIN CARBON STEELS
ACCORDING TO CARBON CONTENT
Type Carbon content properties Applications
Dead mild steel 0.08-0.15% Soft, ductile, can be cold
worked easily
Chains, rivets, nailseam
welded pipe boiler plates,
carpanels
Mild steel 0.15-0.30% Low fluidity, good tensile
strength, high resistance
Structures, screw machine
parts, axles
Medium carbon steel 0.30-0.6% Good strength, high
toughness, better castability
Connecting rod, shafts,
crane hooks
High carbon steel 0.6-0.9% Good strength high
hardness, high toughness,
increased wear resistance
Drop hammers, screw
drivers, saws.
Tool steel 0.9-1.5% High strength and
toughness, good wear
resistance, heat treatable
shock resistance
Springs, axles, knives,
razors.

32. CLASSIFICATION BASED ON DEGREE OF
DEOXIDATION
• Killed steel: the deoxidized steel is called as killed steel. These steels are free from
blow holes and segregation. It contains more than 0.25% carbon.
• Semi killed steel: the partial deoxidized steel is called as semiskilled steel. It is free
from surface blow holes and pipes. It contains 0.15-0.25% carbon.
• Rimmed steel: insufficient deoxidized steel is known as rimmed steel. It consists of
clean and dense surface layer and blow holes are found in center or layers. It
contains 0.15% carbon.

33. EFFECTS OF ALLOYING ELEMENTS OF
CARBON STEELS
• Boron: improves hardenability without the loss of machinability and formability.
• Calcium: deoxidizes steels, improves toughness and may improve formability and machinability.
• Carbon: improves hardenability, strength, hardness, and wear resistance. It reduces ductility, weldability and
toughness.
• Chromium: improves toughness, hardenability, wear and corrosion resistance and high temperature strength. It
increases the depth of hardness penetration.
• Cobalt: improves strength and hardness at elevated temperatures.
• Copper: improves resistance to atmospheric corrosion and to a lesser extent, increases strength with little loss in
ductility.
• Lead: improves machinability. It causes liquid metal embrittlement.
• Manganese: improves hardenability, strength, abrasion , resistance and machinability.
• Molybdenum: improves hardenability, wear resistance, toughness, elevated temperature strength.
• Nickel: improves strength, toughness, corrosion resistance, improves hardenability.
• Silicon: improves strength, hardness, corrosion resistance and electrical conductivity.

34. • Sulphur: improves machinability when compared with manganese, lowers impact
strength and ductility.
• Tungsten: improves strength and hardness at elevated temperatures.
• Vanadium: improves strength toughness, abrasion resistance and hardness at elevated
temperatures it inhibits grain growth during heat treatment.
• Zirconium: produces a fine grained steel.

35. ALLOY STEELS
• Steel is a metal alloy consisting mostly of iron, in addition to small amounts of carbon depending on the grade
and quality of steel.
• Common elements that are added to make alloy steel are molybdenum, manganese, nickel, silicon, boron,
chromium and vanadium.
Properties:
1. To produce fine grained steel.
2. To improve wear resistance, corrosion resistance.
3. To improve machinability.
4. To improve weldability.
5. To improve electrical properties.
6. To improve physical properties at high temperatures.

36. CLASSIFICATION OF ALLOY STEEL BY CHEMICAL
COMPOSITION
1.Ternary alloy steel: it is composed of iron, carbon and one alloying element such as
nickel steel, chromium steel and manganese steel
2.Quarternary alloy steel: it is composed of iron, carbon and nickel-chromium or
cobalt-chromium steel.
3.Complex alloy steel: it is composed of three or more alloying element with iron and
carbon. Such as high speed tool steel, heat resistivity steel etc.,

37. TYPES OF ALLOY STEEL
Name of alloy composition properties Applications
Nickel steel Carbon- 0.35%
Nickel- 3-5%
Iron- rest
High strength, more
ductility, high corrosion
resistance, high
toughness
Aeroplan parts, crank
shaft, propeller shafts
etc.,
Chromium steel Carbon-0.3%
Chromium- 1.6%
High hardness, high
strength, high wear
resistance, high corrosion
resistance, high elastic
limit
Steel gears. Gun barrels,
axles, shafts, tools etc.,
Manganese steel Carbon- 0.5%
Chromium-1-2%
High strength, high
toughness, wear
resistance, low distortion,
good machinability
Gears, shafts, axles, press
tools, cams etc.,
Had field manganese steel Carbon- 1.2%
Manganese- 12%
High strength, high
ductility, excellent wear
resistance
Grinding, railway track
works, gears shafts, gears
etc.,

38. Nickel-chromium steel Carbon- 0.3-0.45%
Nickel-1-2%
Chromium- <1%
High strength,
toughness, hardness,
fatigue strength
Piston pins, worm
gears, crank shafts
gears etc.,
Chrome-vanadium
steel
Carbon- 0.35-0.95%
Chromium- 1%
Vanadium- 0.25%
High strength,
toughness, and
fatigue resistance
Aeroplane parts,
missile parts, axles,
locomotive parts
invar Carbon- 0.1%
Nickel- 35%
Iron- rest
Low coefficient of
thermal expansion
Measuring
instruments, length
standards, measuring
tapes

39. STAINLESS STEEL
• Steels are called stainless because in presence of oxygen they develop a thin, hard adherent film of chromium
oxide that protects the metal from corrosion.
• Properties: corrosion resistance, high strength and ductility and high chromium content.
• Types of stainless steels:
1. Ferrite stainless steel: chromium - 13 to 20 %
carbon - 0.09%
Applications: surgical instruments, utensils, cutlery.
2. Martensite stainless steel: chromium - 10 to 40%
carbon - 0.3%
Applications: gas turbine parts, cutlery and springs.
3. Austenite stainless steel: chromium - 18%
Nickel - 8%
Carbon - 0.06 to 0.12%
Applications: chemical industries, kitchen equipment and domestic proposes.

40. NON-FERROUS METALS AND ALLOYS
material Characteristic
Non-ferrous alloys More expensive than steel and plastic, wide range
of mechanical, physical and electrical properties,
good corrosion resistance.
Aluminium High thermal and electrical conductivity, good
corrosion resistance, good manufacturing
properties.
Magnesium Lightest metal, good strength
Copper High electrical and thermal conductivity, good
corrosion resistance
Super alloy Good strength and resistance to corrosion
titanium Good strength and corrosion resistance

41. ALUMINUM AND ALUMINUM ALLOY
Aluminum:
• it is a silver white metal.
• It is insoluble in water under normal circumstances.
Properties:
1.Low density
2.Ability to resist corrosion
Applications: structural components, aerospace industry, transportation and building.

42. ALUMINIUM AND ALUMINIUM ALLOYS
Aluminium alloy Composition Properties Uses
Duralumin Copper-4%
Magnesium-0.5%
Manganese-0.5%
Iron or silicon-0.7%
Aluminium-rest
Higher tensile strength,
good casting and forging
properties, low corrosion
resistance
Bars, tubes, sheet rivets,
automobile and aircraft
parts
Aluminium-casting alloy Aluminium-90%
Copper-8%
Iron-1%
Silicon-1%
Good strength, hardness
and machinability
Architectural, marine and
ornamental
Aluminium-silicon alloy Silicon-5 to 50%
Iron-rest
Good castability, low
shrinkage
Architectural, marine and
ornamental
Y-Alloy
(Cu-Al alloy)
Aluminium-93%
Copper- 4%
Nickel-2%
Magnesium-1%
High strength at elevated
temperature
Piston of I.c. engines

43. Hindalium Aluminium-95%
Magnesium-5%
Good corrosion
resistance and
weldability
Tubes, gas, oil lines, food
handling equipment
Magnalium Aluminium-95%
Magnesium-5 to 50%
Nickel and tin-small
amount
Greater strength, good
corrosion resistance, low
density
Aircraft and automobile
parts

44. MAGNESIUM AND MAGNESIUM ALLOYS
Magnesium alloy composition properties Uses
Dow metal Magnesium-90%
Aluminium-10%
Extremely light weight,
can be welded or
machined
Automobile and aircraft
industries
Cast magnesium alloy Zirconium and
aluminium
Creep resistance, ductile
and shock resistant
Die castings
Electron metal Aluminium-10%
Zirconium-4%
Manganese-0.55%
Magnesium-rest
Shock resistant, creep
resistance
Machine parts, printing
machines, gear boxes
etc.,

45. COPPER AND COPPER ALLOYS
Copper:
• Copper is a reddish-yellow material and is extremely ductile.
• It has a face centered cubic (FCC) crystal structure and has the second best electrical conductivity of
the metal.
Properties:
1.Extremely ductile
2.High electrical and thermal conductivity.
Applications: rods, plates, sheets, strips, tubes, pipes etc.,

46. COPPER AND COPPER ALLOYS
Alloy composition properties Appliocations
1. Brass
a. ∝-brass (yellow brass)
∝-brass (red brass)
Copper+zinc
20 to 36% zinc
5 to 20% zinc
FCC structure, string and
ductile
Corrosion resistance
Cold rolled into sheets,
wires and tubes, screws
Coins, tokens, fuse caps,
plumbing pipes.
∝-𝛽 brass 54 to 62% copper
33 to 46% zinc
Hard, brittle, castings Hot working, hot
extrusion, hot stamping

47. Commercial brass:
Cartidge brass
Muntz metal
Admiralty brass
Standard brass (high
brass)
70% copper
30% zinc
60% copper
40% zinc
70% copper
29%zinc
1% tin
66% copper
29% zinc
Strong, ductile
Resistance to corrosion,
high tensile strength
Corrosion and abrasion
resistance
Cold working properties
Head lamp reflector,
springs, rivets
Hot rolling, stamping or
extruding
Tubes, plates shafts,
piston rods
Utensils, brass coatings

48. alloy composition properties applications
2. Bronze Copper+ tin
Commercial bronze 2 to 12 % tin 8% tin can be cold
worked
Phosphorus bronze 0.32to 0.5% Pu
6% to 13% tin
Rest copper
High strength corrosion
resistance
Springs, electrical
instruments, bushes
Gun metal 88% copper
10% tin
2%zinc
High corrosion
resistance, harden ability
and machinability
Castings, guns or of
cannons, boiler fittings
Bell metal 80% copper
20% tin
Hard, wear resistance Marine castings,
hydraulic valves, bells
utensils
Berllium bronze 88% copper
1.5% barium
0.5% cobalt
Hard and tough Tools, hammers, chisels

49. NICKELAND NICKELALLOY
Nickel:
• It is a silver-white metal.
Properties:
1.Oxidation resistance
2.High tensile strength
3.Take up high polish
4.Alloys with steel
Applications: coating for food processing equipment, jet engine components, rockets

50. NICKELALLOYS
Alloy Composition Properties Applications
German silver (Ni-silver) 60% copper
30% nickel
10% zinc
Silvery appearance,
corrosion resistance, high
strength
Valves, taps, jewelers,
constantan 45% nickel
55% copper
High resistance Resistors, thermos couples
Monel metal 66% nickel
32% coper
1% iron
1% manganese
Brighter appearance, high
corrosion resistance
Marine equipment, paper
oil, chemical industries
Inconel 80% nickel
14% chromium
6% iron
High resistance to
corrosion, oxidation at
elevated temperature
Air crafts, salt pots, furnace
chambers
nichrome 60% nickel
16% chromium
24% iron
High resistance to
corrosion, oxidation at
elevated temperature
Electrical appliances
Invar (Ni-iron alloy) 40 to 50% Nickel
Rest iron
High strength, Measuring taps, clock
pendulums

51. PROPERTIES OF OTHER NON-FERROUS METALS
metal properties applications
lead Corrosion resistance, high formability, low
electrical conductivity
Pipes and drainage fittings, low
melting solders, bearing materials
zinc Low melting point, high fluidity, high
corrosion resistance, solubility in carbon
Die casting, production of brass,
dry batteries
tin Good resistance acid corrosion, low
strength, high hardness
Preservation of food products, tin
foils
Chromium
Chromium alloys:
Nichrome
Nimonic alloy
White malleable metal, strong and hard,
resistance to wear
Good wear and corrosion resistance, resist
high temperature and oxidation
High strength, ability to operate under
intermittent heating and cooling
Chrome plating and making alloys,
tool steel
Heavy duty rheostats, electrical
heating elements
Gas turbine components

52. BEARING METAL
Alloy composition properties applications
Bearing metal Resistance to wear and corrosion , low
coefficient of friction , good load
bearing capacity, ease of maintenance
Bearing bronze 85% copper +15% tin Tensile strength: 220 n/mm2,
Hardness :100 BHN
Heavy compressive
loads ,slide valves,
bearings
Phosphor bronze 89% copper +11% tin Tensile strength: 280 n/mm2,
Hardness :100 BHN
Heavy load carrying
bearings , sand cast
Admiralty gun
metal
88% copper +10% tin +2%
of lead
Tensile strength: 270 n/mm2,
Hardness :65 BHN
Well lubricated bearings
Babbit metal 85% tin +10 % of antimony,
5% of copper
Excellent antifriction properties High duty bearings
Lead bronze 80% copper +10% tin +10%
of lead
Tensile strength: 230 n/mm2,
Hardness :65 BHN
Aero engines, auto
mobile crank shaft

53. alloy composition properties applications
Cadmium alloy 95% cadmium, 5%
silver
Ability to withstand
high temperatures
Medium loaded
bearings