Materials for Manufacturing

Abdul Khader AA

1. Materials for manufacturing1. Introduction to Engineering Materials

2. Ferrous Metals

3. Mechanical Properties of Metals

4. Properties and Uses of Ferrous Metals

5. Classification of Steel (Grades of Steel ) according to the

Carbon Content

6. High Speed Steel (HSS)

7. Heat Treatment

I. Different heat treatment processes

8. Non-Ferrous Metals

I. Introduction to Non-ferrous Metals

II. Principal Non-ferrous Metals

I. Properties and Uses of Non-ferrous Metals

1. Differences between Ferrous and Non-ferrous Metals

2. Plastic

3. Properties and Applications (Uses) of Ceramic Materials

4. Composite Material Abdul Khader AA

1. Engineering Materials

1. Engineering materials are the solid substances from which an

useful articles can be made by manufacturing Processes.

2. The knowledge of engineering materials and their properties

is of great significance for different disciplines such as

1. Machine design

2. Manufacturing etc.

3. A Proper understanding of structure and properties of material

is essential for a proper design of products and for selecting a

best method for its processing.

Abdul Khader AA

1. Applications of Engineering Materials

1. Steel materials are used for production of bars,

channels, machineries etc.

2. Steel alloys are used for tools, dies, automobile parts

etc.

3. Copper is used in wires, heating element, etc.

4. Aluminum is used for windows, frames, domestic

articles etc.

5. Engineering materials used in construction.

6. Engineering materials are Used in vehicles, ships and

aero planes

7. Engineering materials are used in electronic equipment

Abdul Khader AA

Properties of metals*

Abdul Khader AA

Property*

• Property refers to specific characteristics of metals.

• In engineering properties are important as properties affect the manufacture and use of the metal.

Abdul Khader AA

Mechanical properties

• Mechanical properties are those properties of metal which completely define its behavior under the action of external forces or loads.

Abdul Khader AA

Mechanical properties

1. Elasticity

2. Plasticity

3. Ductility

4. Brittleness

5. hardness

6. Toughness

7. Stiffness

8. Resilience

9. malleability

10.CreepAbdul Khader AA

Elasticity

• Elasticity is defined as the property of the metal by virtue of which it is able to retain its original shape & size after the removal of loads.

Abdul Khader AA

Plasticity

• Plasticity is defined as the property of the metal by virtue of which a permanent deformation (without fracture) takes place under the action of external load.

• Plasticity is the opposite of elasticity. In general plasticity increases with the increase in temperature.

Abdul Khader AA

Ductility

• Ductility is defined as the property of the metal by virtue of which it can be drawn into wires or elongated with the application of tensile force.

• The ductile materials commonly used in engineering practice are mild steel, copper, aluminium, nickel, zinc etc.

Abdul Khader AA

Brittleness

• Brittleness is defined as the property of the metal by virtue of which it will fracture or break without any appreciable deformation.

• Brittleness is opposite to ductility of a material. Cast iron, Glass, Concrete are the examples for brittle materials.

Abdul Khader AA

Hardness

• Hardness is defined as the property of the metal by

virtue of which it is able to resist wear, scratching and

indentation (penetration).

• It also means the ability of a material to cut another material. Hardness is expressed in hardness numbers. Hardness numbers are experimentally determined using Brinell hardness test, Rockwell hardness test, Vickers hardness test etc.

Abdul Khader AA

Toughness

• Toughness is defined as the property of the metal by virtue of which it can absorb maximum energy before fracture takes place.

• Consider a piece of mild steel & glass. When a sudden load is applied to these materials mild steel absorbs much amount of energy before it fails, while the glass breaks suddenly. Thus it is said that the mild steel is much tougher than glass.

Abdul Khader AA

Toughness v/s brittleness

Abdul Khader AA

Stiffness

• Stiffness is defined as the property of the metal by virtue of which it resists deformation or deflection under stress. It is also called as rigidity.

• The stiffness of a metal is measured by its young’s modulus. The higher the young’s modulus, the stiffer is the material.

Abdul Khader AA

Resilience

• Resilience is defined as the property of the metal by virtue of which it stores energy & resist shock & impact loads.

• The maximum amount of energy which can be stored in the material up to the elastic limit is called proof resilience.

Abdul Khader AA

Malleability

• Malleability is defined as the property of the metal by virtue of which it can be rolled or hammered into thin sheets.

• A malleable material should be plastic but it is not essential to be very strong.

• Examples of malleable materials are lead, soft steel, wrought iron, copper etc.

Abdul Khader AA

Creep

• Creep is defined as the property of the metal by virtue of which it undergoes a slow & permanent deformation at constant stress.

• Generally the creep occurs in a material when it is subjected to high temperature for a long period of time.

Abdul Khader AA

Classification of Materials

Ferrous metals and alloys refers to the metals and alloys which contain iron as the base metal E.g.: Pig iron, Cast iron, Wrought Iron, Steels, Alloy steels

Non Ferrous metals : These are the metals or alloys which does not contain Iron as one of the ingredients

E.g.: Copper, Tin, Zinc, brass, bronze

Abdul Khader AA

Ferrous metals

Ferrous metals and alloys refers to the metals and alloys which contain iron as the base metal.Other materials like Carbon, Sulphur, Phosphorus, Manganese, Silicon etc. in small quantities

Abdul Khader AA

Important ferrous metals

• Pig iron

• Cast iron

• Wrought iron

• Carbon steel

• High Speed Steel

Abdul Khader AA

Pig iron

• Impure iron extracted from iron ores is known as pig iron.

• It is the basic raw material for the manufacture of cast iron, wrought iron and steel.

• It is manufactured in a furnace called blast furnace.

• It contains 4 to 5% of carbon.

Abdul Khader AA

Pig ironProperties of pig iron

1. It is hard and brittle.2. It cannot be magnetized.3. It cannot be welded or riveted.4. It does not rust.5. It is difficult to bend.6. It is neither ductile nor malleable.

Uses or applications of pig iron1. It is used for manufacture of wrought iron, cast

iron and steel.2. It is not suitable for commercial use, since it

has high percentage of impurities.

Abdul Khader AA

Cast iron

• It has 2 to 4% of carbon.

• It is widely used type of iron for engineering applications.

Manufacture of cast iron

It is manufactured by remelting pig iron with in a

furnace called CUPOLA.

Abdul Khader AA

Composition of cast iron

Element Effect Percentage

Carbon Makes it hard and brittle 2-4

Manganese Makes it hard and brittle Below 0.75

Phosphorus Increases fluidity Below 0.30

Silicon Removes carbon from

graphite form

Below 2.5

Sulphur Makes it hard and brittle

Causes rapid solidification

resulting in blow holes

Below 0.10

Abdul Khader AA

Properties of cast iron1. It is hard and brittle.

2. It cannot be magnetized.

3. It cannot be riveted or welded.

4. It will not rust easily.

5. It can be hardened by heating and sudden cooling but it cannot be tempered.

6. Its melting temperature is 1250°C.

7. Its specific gravity is 7.5.

8. It is weak in tension and strong in compression.

Abdul Khader AA

Uses of cast iron• For making manhole covers, sanitary fittings, water pipes

and gas pipes.

• For making spiral staircases, ornamental castings such as brackets, gates and lamp posts.

• For making parts of machinery, which require high compression strength and not subjected to impact loads.

• For structural members like columns.

• For preparing agricultural implements and textile machinery.

• For making garden seats, rail chairs and carriage wheels.

Abdul Khader AA

Types of cast iron

1. Gray cast iron

2. White cast iron

3. Malleable cast iron

4. Chilled cast iron.

5. Nodular cast iron

Abdul Khader AA

Wrought Iron

• Wrought iron is a highly refined iron.

• It is prepared from pig iron by burning out carbon, silicon, phosphorus, manganese and sulphur in puddling furnace

• The % of carbon is reduced to 0.02 %and other impurities

Abdul Khader AA

Pig Iron Cast Iron

1 High carbon content (4% by weight)

Low carbon content (2% by weight)

2 Obtained from iron ore Obtained from pig iron

3 More brittle Less brittle

4 Low strength Higher strength

5 Intermediate product of iron ore and useful form of iron

Alloy of iron and carbon used for articles

Abdul Khader AA

Properties of Wrought Iron

• 1. It is tough, malleable and ductile.

• 2. Its ultimate tensile strength is 350 N/mm2.

• 3. It can be forged.

• 4. [t can be readily welded.

• 5. It rusts more quickly than cast iron.

• 6. It can neither be hardened nor tempered like steel.

• 7. High melting point.

• 8. It cannot be used as `Abdul Khader AA

Uses of Wrought Iron

1. It is used for production of nuts and bolts.

2. Used for chains and crane hooks.

3. Used for railway couplings, pipe and pipe fittings.

4. Used for plates, sheets and bars.

5. Used for boiler tubes

Abdul Khader AA

Steel

• It is an important engineering material widely used for engineering purposes.

• Steel is an alloy of iron and steel

• It contains carbon from 0.25 to 1.5 percent.

• All the carbon present in the steel is in the form of compound of iron.

• If the percentage of carbon is more than 1.5 percent it does not combine with iron and forms free Graphite. There is no free graphite in steel.

Abdul Khader AA

Properties and uses of steel

Properties1. Good tensile, compression and shear strength

2. Excellent malleability and ductility.

3. Good machinability and weldability

4. Possess good hardness and toughness

1. Uses1. Casting forging, rolling, drawing, extrusion, etc.

2. Nuts and bolts.

3. Structural girders, automobile bodies, etc.

Abdul Khader AA

Classification STEEL

• Dead Mild steel – : 0.05-0.1% CarbonIt is Highly ductile. It is used for nails, rivets, plates, chains, stampings etc.)

• Low carbon steel or mild steel : 0.1 to 0.3 % CarbonSoft and ductile. It is easily forged, welded and machined. It is used for making chains, bolts, rivets, boiler plates, shafts, pins etc.

• Medium carbon steel : 0.3 to 0.6 %Harder and tougher with less ductile. It is used for axles, rails, heavy forgings, hammers, spanners, etc.

• High carbon steel : 0.60 to 1.7 %It is harder and less tougher than medium carbon steel. It is widely used for cutting tools such as saws, screw drivers, files etc.

Abdul Khader AA

Wrought Iron Steel

1 Pure form of iron An alloy of carbon, steel and other elements

2 Low tensile strength High tensile strength

3 Less vulnerable to corrosion

More vulnerable to corrosion

4 More ductile, less elastic Hard and good plastic property

Abdul Khader AA

COMPOSITION, PROPERTIES AND USES OF High Speed Steel (HSS)

High Speed Steel (Up to 18 % tungsten Up to 4% chromium and upto 1% Vanadium)

Propertieso High heat resistance.o High hardness.o High compressive strength.o Excellent toughness and cutting ability.

Uses• Used for drills, lathe, planer and shaper tools,

milling cutters, reamers, threading dies, punches, etc. Abdul Khader AA

Heat treatment of steel

Abdul Khader AA

Definition

• The heat treatment is defined as an operationinvolving the heating & cooling of metal or an alloy for the purpose of obtaining certain desirable properties.

Abdul Khader AA

The aim/purpose of heat treatment1. To increase the surface hardness of the metal.

2. To relieve the internal stresses set up in the metal after hot or cold working.

3. To improve the Machinability.

4. To soften the metal.

5. To modify the internal structure and modify electrical properties

6. To change the grain size.

7. To provide better heat resistance, corrosion resistance, & wear resistance.

8. To improve mechanical properties like tensile strength, ductility, shock resistance etc. Abdul Khader AA

Process of heat treatment

Process of heat treatment consists of the

following steps

1. Heating the metal to a specific temperature. (near or upto critical temperature)

2. Holding the metal at this temperature for a specified period;

3. Cooling (quenching) the metal according to the specified process.

Abdul Khader AA

Process of heat treatment

• True heat treatment does not involve any chemical change.

• The temperature to which a metal or an alloy is heated depends upon factors like its grade, grain size as well as type & shape.

• The metal is never heated much more beyond its upper critical temperature.

Abdul Khader AA

Heat treatment processes

• Annealing

• Normalising

• Hardening

• Tempering

• Nitriding

• Cyaniding

Abdul Khader AA

ANNEALING

• Annealing is the process of heat treatment for making steel soft so that it can be easily machined

Abdul Khader AA

Purpose of annealing

• To soften the metal so that it can be easily machined or cold worked.

• To refine the grain size & structure to improve mechanical properties like strength & ductility.

• To relieve internal stresses which may have been induced by hot or cold working.

• To alter electrical, magnetic & other physical properties.

• To remove gases trapped in metal during initial casting

Abdul Khader AA

Procedure of annealing

• Depending on the carbon content, steel is heated to a temperature of about 50 to 55 degrees above the critical temperature

• It is held at this temperature for a definite period of time depending on the type of furnace and the nature of the work

• The steel is then allowed to cool inside the furnace gradually

Abdul Khader AA

Application of annealing

• It is applied to castings and forgings

Abdul Khader AA

Normalising

• It is the process of heat treatment carried out to restore the structure of steel to normal condition

Abdul Khader AA

Objectives of normalising

• To promote uniformity of structure

• To secure grain refinement

• To bring about desirable changes in properties like tensile strength

• To improve machinability

Abdul Khader AA

Procedure of normalizing

1. Steel is heated to about 50-55 degrees above the upper critical temperature.

2. It is held at that temperature for a short duration

3. Then the steel is allowed to cool in still air at room temperature (which is quenching in air)

Abdul Khader AA

Application of normalizing

• It is applied to castings and forgings to refine grain structure and relieve stresses

• It is applied after cold working such as rolling, stamping and hammering

Abdul Khader AA

Annealing Normalising1 Steel parts are cooled

slowly in furanceSteel parts are cooled slowly in still air

2 Heating steel parts just below or above critical temperature

Heating 4 C. above critical temperature

3 BHN ranges from 125 to 220

BHN ranges from 140 to 225

4 Parts are comparataivelysoft and easily machinable

Comparatively hard

5 Comparatively more ductile

Less ductile

Abdul Khader AA

Hardening

• Hardening is the opposite of annealing. Here the purpose is to increase the hardness of the steel

Abdul Khader AA

Objectives of hardening

• To increase the hardness of the steel

Abdul Khader AA

Procedure of hardening• Steel is heated above critical temperature range

• It is held at that temperature for specific amount of time

• The steel is then rapidly cooled in the medium of quenching

• The quenching medium is selected according to the degree of hardness desired

• The air, water, brine, oil or molten salts are used as quenching medium

• Water is the widely used medium but results in the formation of bubble on the surface of the metal. Hence brine solution is used to prevent this

• Oil is used when there is a risk of distortion or cracks and is suitable alloy steels.

• The molten salts are used to cool thin sections to obtain crack freeand impact resistant products

Abdul Khader AA

Application of hardening

• It is applied for chisels, sledge hammer, hand hammer, centre punches, taps, dies, milling cutters, knife blades and gears.

Abdul Khader AA

Annealing Hardening1 Steel parts are heated and

cooled slowly in airSteel parts are heated and quenched in water

2 Objective is to soften the metal

Objective is to harden the metal

3 Ductility increases Ductility decreases

4 Refined grain size due to recrystallisation

Reduced grain size due to toughness

5 Relieves internal stress Does not relieve internal stress

Abdul Khader AA

Tempering

• When hardening process hardens a steel specimen, it becomes brittle and has high residual stresses.

• Tempering or drawing results in reduction of brittleness and removal of internal strains caused during hardening.

• Steel must be tempered after hardening process

Abdul Khader AA

Purpose of tempering

• To relieve internal stresses caused by hardening

• To reduce brittleness

• To improve ductility, strength and toughness

• To increase wear resistance

• To obtain desired mechanical properties

Abdul Khader AA

Procedure for tempering

• The steel after being quenched in hardening process is reheated to a temperature slightly above the temperature range at which it is to be used but belowthe lower critical temperature.

• The temperature varies from 100 to 700 degrees.

• The reheating is done in a bath of oil or m+en lead or molten salt. The specimen is held in the bath for a period of time till it attains the desired temper uniformly. The temperature depends on the composition and desired quality of steel.

• Now the specimen is removed from the bath and allowed to cool slowly in still air

Abdul Khader AA

Application of tempering

• It is applied for cutting tools and gears which are hardened by hardening process

Abdul Khader AA

Nitriding

• It is the process of case or surface hardeningin which nitrogen gas is used to obtain hard skin of the metal.

Abdul Khader AA

Purpose of nitriding

• To harden the surface of steel to a certain depth

• To increase resistance to wear and fatigue

• To increase corrosion resistance

Abdul Khader AA

Process of nitriding• It is done in electric furnace where temperature varying

between 450 and 510 degrees is maintained.

• The articles placed in an air tight container provided with outlet and inlet tubes through which ammonia gas is circulated

• The container with the articles is placed in the furnace and ammonia gas is passed through it while the furnace is heated

• During the process of heating, nitrogen gas is released from ammonia in the form of atomic nitrogen which reacts with the surface of the article and form iron nitrate, which is very hard.

• The depth of penetration depends upon the length of time spent at the nitriding temperature.

• The article is taken out and it does not require any quenching or further heat treatment

Abdul Khader AA

Application of nitriding

1. It is applied for hardening the surface of medium carbon alloy steels.

2. It is used in gears, shafts, valves, sprockets,cutters, boring bars and fuel injection pumps

Abdul Khader AA

Cyaniding

• It is the process of surface hardening in which the carbon and nitrogen are added to the surface layer to increase the hardness.

Abdul Khader AA

Purpose of cyaniding

• To increase surface hardness

• To increase wear resistance and fatigue limit

• To give clean, bright and pleasing appearanceto the hardened surface

Abdul Khader AA

Procedure for cyaniding

• The article to be treated is immersed in a molten cyanide salt bath maintained at a temperature of 950 degrees for about 15 to 20 minutes.

• The decomposition of cyanide yields nitrogenand carbon form carbon monoxide, which are diffused into the surface resulting in hardening the surface.

Abdul Khader AA

Application of cyaniding

• It is applied for small articles like bolts, nutsand small gears, bushings, screws, pins and small hard tools which require a thing and hard and wear resistant surface

Abdul Khader AA

Non Ferrous metals

Abdul Khader AA

Non Ferrous Metals

• Non ferrous metals are the metals which do not contain iron.

• They have very low melting point compared to ferrous metals.

Abdul Khader AA

Ferrous metal Non Ferrous metal

1 These are metal which contain iron

Metal which do not contain iron

2 They are magnetic Non Magnetic

3 Low resistance to corrosion High resistance to corrosion

4 More commonly used for engineering structures

Less commonly used

5 E.g: Steel, cast iron Copper, Zinc, Tin

Abdul Khader AA

Important Non Ferrous Metals

1. Copper

2. Aluminum

3. Zinc

4. Tin

5. Lead

6. Nickel

7. Magnesium

Abdul Khader AA

Copper

• It is reddish colored metal.

• It is extracted from ores such as cuprite, copper pyrites and azurite

Abdul Khader AA

Properties of copper

• It can be worked in hot and cold condition but it cannot be welded.

• It is a good conductor of heat and electricity.

• It offers good resistance to corrosion.

• It is highly ductile, malleable and soft.

• It is not attacked by dry air but moist air gives a green coating on its surface.

• It is light in weight.

• Its melting point is 1083°C and boiling point is 2300°C.

• Its specific gravity is 8.92.Abdul Khader AA

Uses of copper

• It can be cast, forged, rolled and drawn into wires.

• It is widely used for making electrical cables and wires.

• It is used in heat exchangers, heating vessels and home appliances.

• It is used for electroplating and for soldering iron bits.

• Used as a coating on steel prior to nickel and chromium.

• It is used for corrosion resistant applications like sheets, boilers and condensers.

Abdul Khader AA

ALUMINIUM

• It is a white metal.

• It is produced from its ore called bauxite.

Abdul Khader AA

Properties of aluminum

• It is silvery white metal with bluish tinge.

• It is light in weight, malleable and ductile.

• It is a very good conductor of heat and electricity.

• It is very soft and non-magnetic metal.

• It is highly resistant to corrosion and non-toxic.

• It is rarely attacked by acids.

• It possesses great toughness and tensile strength.

• Its melting point is 658°C and boiling point is 2056°C.

• Its specific gravity is 2.7.

Abdul Khader AA

Uses of aluminum

• Due to its lightweight it is used to manufacture aircraftand automobile components.

• It is used in power transmission cables, electric bulbs and electric conductors.

• It is used in cooking utensils since it is non-toxic.

• Used to manufacture window frames.

• Used in manufacture of chemical containers.

• It is widely use for mirrors, reflectors and telescopes.

• It is used in surgical instruments.

• It is used for manufacturing paints in powder form.Abdul Khader AA

ZINC

• It does not occur in free state and is manufactured from its ores such as zincite, franklinite and zinc blende.

Abdul Khader AA

Properties of zinc

• It is a bluish white metal and burns with greenish flame.

• It is a brittle at room temperature.

• It is a good conductor of heat and electricity.

• It is not affected by dry air and pure water.

• It is damaged by acid, hot water and sea salt.

• It resists corrosion.

• Its melting point is 419.4° C and boiling point 907 °C.

• Its specific gravity is 7.14Abdul Khader AA

Uses of zinc

• It is used as protective coating on iron, iron vessel, steel and corrugated sheets in the form of galvanized surface (coating of zinc is known as galvanizing)

• It is used in electric cells.

• It is used in the preparation of alloys and paints

• It is used for lining to the drinking water storage tanks.

Abdul Khader AA

TIN

• Tin is extracted from its ore called as tin cassiterite.

Abdul Khader AA

Properties of tin

• It is a brilliant white metal with a yellowish tinge.

• It is soft, malleable ductile and can be rolled into very thin sheets.

• It is not affected by dry air, pure water and withstands corrosion due to acids.

• It is dissolved in hydraulic acid with evolution of hydrogen.

• It becomes brittle above 200 0 C.

• Its melting point is 232° C and boiling point 769 °C.

• Its specific gravity is 7.31. Abdul Khader AA

USES of Tin

• It is used for plating, lining lead pipes.

• It is used as protective coating for copper and iron utensils.

• It is used for coating steel sheets, which are used for making cans for food, fruit and milk.

• It is used for silvering of mirrors.

• It is used for packing cheese, chocolate, tobacco,

toilet soaps

Abdul Khader AA

LEAD

• Lead does not occur in free state in nature. It is found in the form of lead sulphide called galena

Abdul Khader AA

Properties of lead• It is blush gray metal with a bright and shinning metallic

surface when freshly cut.

• It is the softest and heaviest of all the common metals.

• It gives very dull sound when struck and makes dark impression on paper.

• It has a very little tenacity.

• It is highly plastic and malleable and possesses least causticity.

• It is readily soluble in dilute nitric acid.

• It is not attacked by dry air, but moist air forms a dark protective film on its surface.

• Its melting point is 327.5 C and boiling point is 1600 C

• Its specific gravity is 11.36.

Abdul Khader AA

Uses of lead

• It is widely used for making shots bullets and alloy.

• It is used for making sheaths for electric cables and bearing metals solders.

• It is used for storage batteries, sanitary fittings and X-ray shields.

• It is used for making waterproof and acid proof, gutters, and damp proof courses of buildings.

• It is widely used for the preparation of lead oxides for paints.

Abdul Khader AA

NICKEL

• Nickel is obtained from the ore of copper, manganese and iron but the maximum quantity is obtained from iron sulphide ores.

Abdul Khader AA

Properties of nickel

• It is silvery white metal capable of taking a high polish.

• It is highly resistance to corrosion.

• It is almost as hard as steel but less ductile.

• It is malleable, magnetic and can be easily welded.

• It is not attacked by most acids but it dissolves readily in nitric acid.

• Its melting point is 1452°C and boiling point is 2900°C

• Its specific gravity is 8.90.

Abdul Khader AA

Uses of nickel

• The iron and steel particles are nickel plated to protect them from rusting.

• It is used for cooking utensils and vessels for heating and boiling.

• It is used as a constituent in several ferrous steels and non-ferrous alloys like German silver and nickel.

• It is used as catalyst in several industrial processes.

• It is used for making chemical apparatus, crucibles, electroplating of machine parts etc.

Abdul Khader AA

MAGNESIUM

• It is available in natural salt brines, seawater and water liquids from potash industry.

Abdul Khader AA

Properties of magnesium

• It is lightest of all metals, about 67% lighter than aluminum.

• It possesses good castability.

• It can be easily spun, formed, drawn, forged and machined with high accuracy.

• It is inflammable in finely divided form.

• It has poor corrosion resistance.

Abdul Khader AA

Uses of magnesium

• It is used to manufacture castings of motorcar gearbox, differential housing and portable.

• It is used to manufacture material handling equipments like hand trucks, barrel skids and gravity conveyors.

• It is used in typewriters, calculators, binocular and camera bodies.

• It is used to manufacture storage tanks, components of textile and printing machines and ladders.

• It is used in components of aeroplanes, missilesand space shuttles.

Abdul Khader AA

Plastic

• Plastic may be defined as organic material that can be easily moulded or shaped to give non-crystaliinesubstances that are solid at ordinary ternperatrtres.

• Plastics are made up of long-chain molecules based on carbon and hydrogen.

• Thebasic raw materials for the plastics are coal petroleum, cotton, wood, gas, air, salt and water. Plastics may be classified into two branches:

1) ThermoPlastic

2) Thermosetting PlasticsAbdul Khader AA

Properties of plastics

1. Good compressive strength

2. Excellent tensile strength

3. Good machining Properties

4. Good chemical resistance

5. They are insoluble and fire proof up to certain temperature

6. Can be shaped easily'

7. They are rigid.

8. High wear resistant with low density

9. Good creep resistance.

10. Good corrosion resistance

11. Low melting Point.

12. Light and strong.

13. Low specific gravity

14. Low coefficient of friction High thermal expansion Abdul Khader AA

Uses of plastics1. Used for adhesives and coatings.

2. Used for rubber compounds, resins, oils etc.

3. Used in radio cabinet, TV cabinet, computers, etc.

4. Used in electric materials

5. Used for bags, bottles etc.

6. Used for printed circuit boards, boats, etc.

7. Used for taps, Pipes, tanks etc.

8. Used for lab equipment, insulators, capacitors, etc

9. Used as floor and decorative materials

10.Used as a thermal barriers etc.Abdul Khader AA

Thermo plastics

1. The plastics which are softened by the application of heat without pressure and harden on cooling are known as thermos plastic plastics.

2. Thermoplastics are linear polymers, the molecules of which are synthesized in the shape of long threads.

3. They undergo no chemical change in the mouldingoperation and is becomes soft with the application of heat and harden upon cooling

4. Then can be reshaped while in the softened state and they will reharden, therefore the scrap can be used again.

Abdul Khader AA

Properties and Thermo plastics

Properties :

1. Good compressive strength (210 N/mm2)

2. Excellent tensile strength (55 N/mm2)

3. Good machining Properties

4. Good chemical resistance.

Uses :

1. These are best suited for shrink fit packaging

2. Used as binding materials for grinding wheels, phonographic discs

3. Used in toilet materials, Pens, tooth brushes, radio dials etc. Abdul Khader AA

Common Thermo-plastics1. Polyethylene

2. P.V.C.

3. Polystyrene

4. Polypropylene

5. Nylon

6. Silicones

7. Bitumen

8. Polymides

Abdul Khader AA

Thermo-setting plastics

1. The plastics which are softened by the application of heat and pressure and harden on cooling are known as thermosetting plastics.

2. Thermosetting plastics are made from chains which have been linked together referred to as a cross-linked. These have a three dimensional network of molecules

3. They will not soften when heated.

4. They are practically insoluble, fireproof and usually hard and brittle.

5. These plastics cannot be reused. The thermosetting plastics are popular due to their properties like hardness, rigidity and heat resistant. Abdul Khader AA

Different Thermo-setting plastics

1. Phenol formaldehyde

2. Urea formaldehyde

3. Melamine formaldehyde

4. Polysters

5. Silicons .

6. Epoxy resins .

7. Phenolics.

Abdul Khader AA

Properties of Thermo-setting plastics

1. These are hard and brittle

2. They are rigid.

3. High heat resistant.

4. They are insoluble and fire proof

5. They can not be reused.

Abdul Khader AA

Uses of Thermo-setting plastics

1. Used for printed circuit boards, boat bodies etc. .

2. Used for radio cabinet, electric switch cover plates, insulators, etc.

3. Used for adhesives and coatings.

4. Used for rubber compounds, resins, oils, greases etc.

Abdul Khader AA

Ceramic Materials

1. A ceramic material is an inorganic, non-metallic, often crystalline oxide, nitride or carbide material.

2. Some elements, such as carbon or silicon, may be considered ceramics.

3. Ceramic materials are brittle, hard, strong in compression, weak in shearing and tension.

Abdul Khader AA

Ceramic Materials uses

1. These are used for cutting tools and engine components

2. Used for coating of cutting tools and engine components

3. Used as a thermal barriers

4. Used in fuel cells, glassware, 'dinner ware' etc.

5. Used in safety glass windshields in automobiles.

6. Used as structural components for ground flooring

7. Used as a decorative material’

8. Used in glass fibers and optical fibers

9. Used in insulators, capacitors and IC packagesAbdul Khader AA

Ceramic Materials – uses 9. Ceramic abrasives are used in grinding wheels,

polishing wheels

10. Ceramic abrasives are used for polishing, lapping and Pressure blasting of materials.

11. Used in refractories, chemical industries.

12. These are used in turbine blades, knife, exhaust manifolds in automobile's etc.

13. To build the ceramic balls for bearings.

14.To replace human body parts like orthopedic joint replacement, bone implants, dental restoration, etc.

15. Used in bricks, lab equipment, cements membranes etc.

16. Used in communication equipment like TV and radio components

Abdul Khader AA

Composite Materials• Composite materials are the combination of two or

more organic or inorganic components.

• One component acts as a "matrix", which holds everything together while the other component acts as a reinforcement in the form of fibre embedded in the matrix.

• Generally, the thermosetting materials like epoxy, polymide, etc., can be used as a matrix materials.

• Where as glass fibre, boron fibres, etc., can be used as a reinforcing materials.

• The compound materials are incorporated into the composite to take advantage of their properties and their applications.

Abdul Khader AA

Properties of Composite Materials1. High strength of weight ratio.

2. High stiffness to weight ratio.

3. Good wear resistance.

4. Superior magnetic Properties.

5. High modulus of elasticity.

6. Superior mechanical properties.

7. High resistance to thermal expansion.

8. Good corrosive resistivity

9. Excellent fatigue resistance.

10. Improved toughness.

11. Occupy less space. Abdul Khader AA

Uses / Properties of Composite Materials1. High temperature structures.

2. Aerospace applications where light weight, stiffness and fatigue resistance are essentially required.

3. Used in gas turbines.

4. Used in Storage battery plates.

5. High temperature engine Parts.

6. Structural walls, shells, cylinders, pipes, etc.

7. Used in reactors.

8. Electrical components.

9. Used in pressure vessels and sea mining equipment.

10. Used in aircrafts.Abdul Khader AA