001- engineering skills principles-1 chapter - 03...

001- Engineering Skills Principles-1

Chapter - 03 Material

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Objective of Chapter 3.0 (Material)

� The aim of this section is to enable the candidate to:

1. Identify metals and compare their properties.

2. Understand the effect that material shape, and the position of

force, has on deflection.

3. Be aware of the causes of rusting, and effects of cold working

and heat treating plain carbon steels.

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TOPIC 3.1TOPIC 3.1TOPIC 3.1TOPIC 3.1

• Introduction to Material Science

• Materials • Materials

• Basic Properties Of Materials

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• Defined as the study of the properties of solid materials

and how those properties are determined by a material’s

Introduction to Material Science

and how those properties are determined by a material’s

composition and structure.

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• What are Materials?

• That’s easy! Look around.

• Our clothes are made of materials, our homes are made of

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• Our clothes are made of materials, our homes are made of

materials - mostly manufactured. Glass windows, vinyl siding,

metal silverware, ceramic dishes…

• Most things are made from many different kinds of materials.


� Kinds of Materials

1. Metals

2. Ceramics

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3. Plastic

4. Semiconductor

5. Composites material


• Kinds of Materials• Metals: are materials that are normally combinations of "metallic

elements". Metals usually are good conductors of heat and electricity. Also, they are quite strong but malleable and tend to have a lustrous look when polished.

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have a lustrous look when polished.

Metals


• Kinds of Materials

• Ceramics: are generally compounds between metallic and

nonmetallic elements. Typically they are insulating and resistant

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to high temperatures and harsh environments.

Ceramics


• Plastics: are generally organic compounds based upon carbon

and hydrogen. They are very large molecular structures. Usually

they are low density and are not stable at high temperatures.

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Plastic


• Semiconductors: A semiconductor is a material with electrical

conductivitydue to electron flow (as opposed to ionic conductivity)

intermediate in magnitude between that of a conductorand an insulator.

Semiconductor materials are the foundation of modern electronics, including

radio, computers, telephones, and many other devices. Such devices include

transistors, solar cells, many kinds of diodes.

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• Composites: Composite materials, often shortened to composites,

are engineeredor naturally occurring materialsmade from two or

more constituent materials with significantly different physicalor more constituent materials with significantly different physicalor

chemical propertieswhich remain separate and distinct at the

macroscopicor microscopic scalewithin the finished structure.

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Material

• History of Materials

• Our history has been defined by the materials we use…

• The stone age

• The copper age

• The bronze age

• The Iron age

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Material

• IRON AND STEEL

• Iron Ore: Iron taken from a mine looks like clay. It is found combined with

oxygen. The ore generally contain small amount of sulphur, Phosphorus,

silicon manganese , copper etc.

� Types of Iron Ore� Types of Iron Ore

1. Black Magnetite

2. Red Hematite

3. Brown siderite

4. Brown Limonite

5. Iron pyrite

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Material

• STEELSteel is an alloy that consists mostly of iron and has a carboncontent between

0.2% and 2.1% by weight, depending on the grade. Carbon is the most

common alloying material for iron, but various other alloying elements are common alloying material for iron, but various other alloying elements are

used, such as manganese, chromium, vanadium, and tungsten

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Material

• CARBON STEEL

Also called plain-carbon steel, is steelwhere the main alloying

constituent is carbon. The American Iron and Steel Instituteconstituent is carbon. The American Iron and Steel Institute

(AISI) defines carbon steel as: "Steel is considered to be carbon

steel when no minimum content is specified or required for

chromium, cobalt, columbium, molybdenum, nickel, titanium,

tungsten, vanadiumor zirconium.

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• Types of Carbon Steel

Material

Sr.NO. Name Percentage of Carbon

1 Dead mild steel 0.05% - 0.15 %

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1 Dead mild steel 0.05% - 0.15 %

2 Mild steel 0.15% - 0.3 %

3 Medium Carbon Steel 0.3 % - 0.5 %

4 High Carbon Steel 0.5 % - 1.3 %

• CAST IRON Cast iron is considered an alloy of iron, silicon and carbon. the carbon contents are usually adjusted in the rang of 1.7 to 4.5%,most of which is present in insoluble form (e.g graphite flakes)

• APPLICATION

Material

• APPLICATIONCast iron tends to be brittle, except for malleable cast irons. With its relatively low melting point, good fluidity, castability, excellent machinability, resistance to deformation and wear resistance, cast irons have become an engineering materialwith a wide range of applications and are used in pipes, machines and automotive industryparts.

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Material• CASTING

A manufacturingprocess by which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process.

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• ALUMINUMIs a silvery white member of the elements. It has the symbol Al. It is not soluble in water under normal circumstances. Aluminum is the third most abundant element, after oxygenand silicon.

• CHARACTERISTICSAluminum is a soft, durable, lightweight, ductileand malleable

Material

Aluminum is a soft, durable, lightweight, ductileand malleablemetalwith appearance ranging from silvery to dull gray, depending on the surface roughness. Aluminum is nonmagnetic and nonsparking and resistance to corrosion.

• Properties.� Melting point933.47K, 660.32 °C, 1220.58 °F

� Boiling point2792K, 2519 °C, 4566 °F

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• COPPERIs a chemical elementwith the symbol Cu. . Pure copper is rather soft and malleable, and a freshly exposed surface has a reddish-orange color. It is used as a thermal conductor, an electrical conductor, a building material, and a constituent of various metal alloys.

Material

alloys.• CHARACTERISTICS

It is a ductilemetal, with very high thermal and electrical conductivity. Pure copper is rather soft and malleable. It is good resistance to corrosion

• Properties � Melting point1357.77K, 1084.62 °C, 1984.32 °F� Boiling point2835K, 2562 °C, 4643

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Material• BRASS

Is an alloy of copperand zinc; the proportions of zinc and copper can be variedto create a range of brasses with varying properties.

APPLICATIONAPPLICATIONIs a substitutional alloy. It is used for decoration for its bright gold-like appearance; for applications where low friction is required such as locks, gears, bearings, doorknobs, ammunition, and valves; for plumbing and electrical applications; and extensively in musical instruments

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• Austenitic stainless steel.Steels have austeniteas their primary phase (face centered cubiccrystal). These are alloyscontaining chromiumand nickel(sometimes manganeseand nitrogen), structured around, 18%

Material

(sometimes manganeseand nitrogen), structured around, 18% chromium, and 8% nickel. Austenitic steels are not hardenableby heat treatment.

• CHARACTERISTICS

• Austenitic stainless steels have high ductility, low yield stress and relatively high ultimate tensile strength, when compare to a typical carbon steel.

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Basic Properties Of Materials

• Ductility

Ductility is the property that enables a material to stretch, bend, or twist without cracking or breaking. This property makes it possible for a material to be drawn out into a thin wire.

• MalleabilityMalleability is the property that enables a material to deform by compressive forces without developing defects. A malleable material is one that can be stamped, hammered, forged, pressed, or rolled into thin sheets.

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• Hardness Hardness refers to the ability of a metal to resist abrasion, penetration, cutting action, or permanent distortion. Hardness may be increased by working the metal and, in the case of steel and certain titanium and aluminum alloys, by heat treatment and and certain titanium and aluminum alloys, by heat treatment and cold-working

• ToughnessA material that possesses toughness will withstand tearing or shearing and may be stretched or otherwise deformed without breaking. Toughness is a desirable property in aircraft metals.

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• ElasticityElasticity is that property that enables a metal to return to its original shape when the force that causes the change of shape is removed. This property is extremely valuable, because it would be highly undesirable to have a part permanently distorted after an applied load was removed. Each metal has a point known as the elastic limit, beyond which it Each metal has a point known as the elastic limit, beyond which it cannot be loaded without causing permanent distortion.

• BrittlenessBrittleness is the property of a metal that allows little bending or deformation without shattering. In other words, a brittle metal is apt to break or crack without change of shape. Because structural metals are often subjected to shock loads, brittleness is not a very desirable property. Cast iron, cast aluminum, and very hard steel are brittle metals.

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Basic Properties Of Materials• Conductivity

Conductivity is the property that enables a metal to carry heat or electricity.

• Heat ConductivityThe heat conductivity of a metal is especially important in The heat conductivity of a metal is especially important in welding, because it governs the amount of heat that will be required for proper fusion.

• Electrical conductivity Is the reciprocal quantity, and measures a material's ability to conductan electric current.

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• Strength Strength is the property that enables a metal to resist deformation under load. The ultimate strength is the maximum strain a material can withstand. Tensile strength is a measurement of the


material can withstand. Tensile strength is a measurement of the resistance to being pulled apart when placed in a tension load.

The material must possess the strength required by the demands of dimensions, weight, and use. There are five basic stresses that metals may be required to withstand. These are tension, compression, shear, bending, and torsion.

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• Machinability• The term machinability refers to the ease with which a metal can

be machinedto an acceptable surface finish. Materials with good machinability require little power to cut, can be cut quickly, easily machinability require little power to cut, can be cut quickly, easily obtain a good finish, and do not wear the tooling much; such materials are said to be free machining. The factors that typically improve a material's performance often degrade its machinability. Therefore, to manufacture components economically, engineers are challenged to find ways to improve machinability without harming performance.

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• Identification Methods

• Identify Metals In 3.1

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• Because of the widespread use and necessity for metals in Manufacturing it is

important for the worker to have a basic understanding of metals and

metallurgy when fabricating and making repairs on metals.

IDENTIFICATION METHODS

metallurgy when fabricating and making repairs on metals.

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• Many methods are used to identify a piece of metal. Identification is necessary when selecting a metal for use in fabrication or in determining its behavior.

IDENTIFICATION METHODS

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IDENTIFICATION METHODS• Some basic methods used for Metal identification are:

Use of magnet

Color

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Density

Basic methodsOf

Identification

Copper• ColorSome metals can be easily identified by Color test

Reddish Brown

IDENTIFY METALS IN 3.1

Reddish Brown

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CopperDensity testD =8.94 g/cmFormulaD = M / V AM=8.94*46.875M= 419.062 g


DENSITY CHART

3

3

M= 419.062 gIf put all value in equation-AD=419.062/46.875D=8.94 g/cmAns.

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Elements Volume(cm ) Mass(gm) Density

Copper 25x25x75mm - ?

3

3

CopperDensity test


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Copper piece Reference weight

Copper pieceReference weight

Aluminum• Color

Whitish


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Aluminum

Density test

FormulaD = M / V


DENSITY CHARTD = M / V

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Elements Volume Mass(weight) Density

Aluminum 25x25x75mm - ?

AluminumDensity test


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Aluminum piece Reference weight

Aluminum pieceReference weight

Brass• Color

Yellow if high zinc content


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Brass

• Density test

FormulaD = M / V



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Alloy Volume Mass(weight) Density

Brass 25x25x75mm - ?

Brass• Density test


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Aluminum piece Reference weight

Aluminum pieceReference weight

Austenitic Stainless Steel• ColorBright silvery smooth


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Austenitic Stainless Steel

Density test

FormulaD = M / V



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Aus. Stainless Steel 25x25x75mm - ?

Austenitic Stainless Steel• Density test


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Aus. Stainless steel piece Reference weight

Aus. Stainless steel pieceReference weight

Cast Iron• Color Test

Dull gray


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Cast Iron

Density test

FormulaD = M / V


DENSITY CHART

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Cast Iron 25x25x75mm - ?

Cast Iron• Density test


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Cast Iron piece Reference weight

Cast Iron pieceReference weight

Carbon Steel Color Test

Dark gray


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Carbon Steel

Density test

FormulaD = M / V



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DENSITY CHART


Carbon steel 25x25x75mm - ?

Carbon Steel• Density test


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Carbon Steel piece Reference weight

Carbon Steel pieceReference weight



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• Identify Metals In 3.1 As Non Ferrous or

Ferrous Metal

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Ferrous Metal & Non ferrous Metal

� Ferrous Metal

• ferrous metals are those which

contain iron as a principle

ingredient.

� Non ferrous Metal

• Non ferrous metals are those

which do not contain iron.

8/16/2011 56Aluminium

Cast iron

MetalMetal

FerrousFerrous

Carbon SteelCarbon Steel

Cast IronCast Iron

CopperCopper

Ferrous Metal & Non ferrous Metal

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Non-ferrousNon-ferrous

BrassBrass

AluminumAluminum

Austenitic stainless Steel

Austenitic stainless Steel

Copper

• Magnetic testThe use of a magnet is another method used to help in the general identification

Of metals. Remember that ferrous metals, being iron-based alloys,

normally are magnetic, and nonferrous metals are nonmagnetic.


normally are magnetic, and nonferrous metals are nonmagnetic.

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•After magnetic test no attraction or repulsion were taken place.

•Copper is Non magnetic metal .

Aluminum

�Magnetic test


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•Aluminum is Non magnetic metal .

Brass

�Magnetic test


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• Brass is Non magnetic alloy .

Austenitic Stainless Steel

• Magnetic test


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•After magnetic test no attraction or repulsion were taken place.(it may be magnetic but in case of exact analysis )

• Stainless steel is Non magnetic alloy .

Cast Iron• Magnetic test


•After magnetic test attraction were taken place.

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• Cast Iron is Strongly magnetic alloy .

Carbon Steel• Magnetic test


•After magnetic test attraction were taken place.

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• Cast Iron is Strongly magnetic alloy .



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2. Understand the effect that material shape, and the position

of force, has on deflection.



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Carry out simple comparative deflection tests between

specimens of equal length and cross-sectional area,

centrally loaded and simply supported at each end.

a) Flat bar face down

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a) Flat bar face down

b) Flat bar edge down

c) “I” Section vertical

d) “I” Section horizontal

e) Tube

DEFLECTIONDefinition:

•The amount of deviation from a straight line or plane when

a force is applied.

•May be permanent or temporary deformation.

Sometimes called:Sometimes called:

•Deformation, buckling, bending…

Practical Examples;

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SIMPLY SUPPORTED BAR

Support

Bar

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Tension

CompressionLoad

SPECIMEN

•Equal length

•Equal thickness

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Flat Bar “I” Section Tube

Flat Bar Face Down

Load

Support

Bar

Support

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Tension

CompressionLoad

Flat Bar Edge Down

Load Load

Bar

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Support Support

Flat Bar Edge Down

Compression

A

Load

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Tension

Support Support

A

B

“I” Section Vertical

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“I” Section Horizontal

Load

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Tube

Load

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• Describe the properties of non-metallic materials (other than timber) and their usage.

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Non-metallic Materials

� Nonmetallic Materials

• a substance such as wood, plastic or

fabric that is not made of metal Plastic

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Rubber

Ceramicsfabric


• Properties� Non-lustrous

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• Properties� Brittle or Soft

Brittleness

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Softness Brittleness

Softness

Brittleness

Non-metallic Materials• Properties� Poor Conductor of Heat and Electricity

Plastic for example is a poor conductor because it is an insulator. Plastic is made up of a substance that dose not allow the flow of electrons.

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Poor conductor

of Electricity

Poor conductor of

Heat


• Properties� Shock AbsorptionA property has a ability to absorb shock or impact.

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No Fracture Was Found On Safety Helmet

Non-metallic Materials• Properties

Acoustic QuietingAcoustic Quieting

Noise absorptionNoise absorption Sound isolationSound isolation Acoustic dampingAcoustic damping

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To prevent it from transferring out of

one area

To prevent it from transferring out of

one area

Sounds can be absorbed rather than reflected inside the

place

Sounds can be absorbed rather than reflected inside the

place

To prevent vibration from transferring beyond the device

into another material

To prevent vibration from transferring beyond the device

into another material

Sound Proof Room

Non-metallic Materials• Advantages from the use of plastic for Pipe

Light in weight and

tough

Light in weight and

tough

Good elastic properties

Good elastic properties

They are rust resistant

They are rust resistant

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Plastic pipe

Plastic pipe

Resistant to chemical

attack


attack

Available in large lengthsAvailable in

large lengths

Reduces chances of

leakage.

Reduces chances of

leakage.

Smooth internal

surface of the pipes offer less friction

Smooth internal

surface of the pipes offer less friction

Non-metallic Materials• Advantages from the use of plastic for Conduit

FlexibilityFlexibility

Friction less Friction less

used for

protecting

electrical

used for

protecting

electrical

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Plastic Condui

t

Plastic Condui

tResistant to

chemical attack


attack

Remains ductile at low temperatures

Remains ductile at low temperatures

Continuous

Coils

Continuous

Coils

electrical

wiring

electrical

wiring

Non-metallic Materials• Disadvantages from the use of plastic for Pipes

They are

easily

cracked

They are

easily

cracked

At higher

temperature

At higher

temperature

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Plastic Pipes

Plastic Pipes

temperature

s, the

strength of

plastic pipes

reduces

temperature

s, the

strength of

plastic pipes

reduces

plastic pipes

are not

installed in

high

temperature

plastic pipes

are not

installed in

high

temperature

Not

environment

Friendly

Not

environment

Friendly

Raw Material

Costs

Raw Material

Costs

Non-metallic Materials• Disadvantages from the use of plastic for Conduit

Not conveyance for liquid or

gases

Not conveyance for liquid or

gases

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Plastic ConduitPlastic Conduit

Not

environment

Friendly

Not

environment

Friendly

High Raw

Material Costs

High Raw

Material Costs



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• Explain the difference between thermoplastic and thermosetting plastics and state suitable applications.applications.

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Thermoplastic And Thermosetting Plastics

Thermoplastic

� Thermoplastics can be shaped

easily by being cooled and heated

time and time again.

Thermosetting Plastics

� Thermo set on the other hand

cannot be repeatedly heated,

cooled and shaped.

� These can be softened as often as

they are reheated.

� They are not so rigid.

cooled and shaped.

� If heat the thermosetting

material gets hardened the first

time and if we again heat it, just

burns without deforming.

� They are so rigid.

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• Application of Thermoplastic

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Nylon

Thread

Polystyrene Car

Prototype

Polythene Bag


• Application Of Thermosetting Plastic

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Car door Handle

Socket Chair



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• State The Changes In Physical And Mechanical Properties Of Steel Due To Cold Working.

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Cold Working.

• Altering the shape or size of a metal by plastic deformation.

• The process is usually performed at room temperature, but slightly elevated

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but slightly elevated temperatures may be used to provide increased ductility and reduced strength

Material

Cold Working.

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Changing effect in Steel due to Cold Working.

Physical Properties

• Bright Surface

• Good surface finish

Mechanical Properties

• Strength And Rigidity become

increase

• It becomes hard• accurate to size

• free from scale

• It becomes hard

• Ductility becomes low

• makes the steel more brittle

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Bright Surface Through Out Accurate Size

Good Surface Finish

Free From Scale


Strength and Rigidity

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Ductility becomes low and brittleness increases



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• State the changes in physical and mechanical properties of steel due to temperature changes.changes.

• Effects of: hardening, tempering, annealing, normalizing, recrystallization, grain growth

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Changes In Physical And Mechanical Properties Of Steel Due To Temperature Changes.

• Heat Treatment Process

• To Improve mechanical properties of a material heat treatment process is used

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Mechanical Property

Mechanical properties are defined as those material properties that measure a material's reaction to applied force.

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Hardness Toughness Tensile strength

applied force.


Physical Property

Physical properties are properties other than mechanical properties that

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Density Heat conductivity

Magnetic

mechanical properties that depend on the physics of the material.

Changes In Physical Properties

• Thermal Expansion of Steel

Is the tendency of steel to

change in volume in response to

Gap is given between track joint to avoid deformation

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change in volume in response to

a change in temperature .All

materials have this tendency. Otherwise deformation

can takes place

• Magnetic Property


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At Room temperature

magnet attract with steel work

piece

At Room temperature

magnet attract with steel work

piece

After the heating to

steel’s grains, no attraction

took place with magnet.

After the heating to

steel’s grains, no attraction

took place with magnet.

• Density


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At Room temperature

Density of steel

remains same

At Room temperature

Density of steel

remains same

Density of steel will Decrease

after heating effect .

Density of steel will Decrease

after heating effect .

• Hardening

This is the process of heating a

piece of steel to a temperature

Changes In Mechanical Properties

HardeningHardening

Physical ChangesPhysical Changes Mechanical Mechanical

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within or above its critical

range and then cooling it

rapidly

Physical ChangesPhysical Changes

Steel might be distorted or cracked or scratches free

and we can get shiny surface

Steel might be distorted or cracked or scratches free

and we can get shiny surface

Mechanical Changes

Mechanical Changes

Steel becomes hard

Steel becomes hard

• Tempering

Quench-hardened steels are brittle as

well as hard. To make them suitable

for cutting tools they have to be

reheated to a specified temperature


TemperingTempering

Physical ChangesPhysical Changes Mechanical Mechanical

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reheated to a specified temperature

between 200 and 300◦C and again

quenched.


To make them suitable for

cutting

To make them suitable for

cutting

Mechanical Changes

Mechanical Changes

Steel becomes tough (ie

resistance to shock or impact)



• AnnealingMetal cools down in the furnace itself or by burying it in ashes or lime. This annealing process makes


AnnealingAnnealing


Mechanical Changes

Mechanical Changes

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annealing process makes the metal very soft and ductile.

ChangesChanges

Steel can be bent or

Formed easily

Steel can be bent or

Formed easily

ChangesChanges

Makes the metal very soft

and ductile.

Makes the metal very soft

and ductile.

• Normalizing

Steel cools down in free air.

Although the cooling is slow, it

is not as slow as for annealing so

the metal is less soft and ductile.


NormalizingNormalizing

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the metal is less soft and ductile.

This condition is not suitable for

flow forming but more suitable

for machining.


Steel can not be bent or formed easily but

machined easily

Steel can not be bent or formed easily but

machined easily

Mechanical Changes

Mechanical Changes






• Recrystallisation

Is the term used when the

distorted grains reform when

they are heated. During

recrystallization, the badly

RecrystallisationRecrystallisation

Physical Physical Mechanical Mechanical recrystallization, the badly

deformed grains are replaced by

new, strain-free grains. New

orientations, new grain sizes.


Steel can be bent or formed easily .Steel can be bent or formed easily .

Mechanical Changes

Mechanical Changes

The strength reduces and the

ductility increases

The strength reduces and the

ductility increases

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Changes In Mechanical Properties• Grain Growth

Grain growth is the growth of

some recrystallized grains, and it

can only happen at the expense of

other recrystallized grains.

Because fine grain size leads to

Recrystallisation

Recrystallisation


Mechanical Changes

Mechanical ChangesBecause fine grain size leads to

the best combination of strength

and ductility, in almost all cases,

grain growth is an undesirable

process.

ChangesChanges

Steel can be bent or formed

easily .

Steel can be bent or formed

easily .

ChangesChanges

The strength reduces and the ductility

increases

The strength reduces and the ductility

increases

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THANK YOUTHANK YOU

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001- engineering skills principles-1 chapter - 03...

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