Lab Manual - Maharashtra Institute Of Technology

MATERIALS AND METALLURGY

MAHARASHTRA INSTITUTE OF TECHNOLOGY,

DEPARTMENT OF MECHANICAL ENGINEERING

LAB MANUAL


(MED 322)

G.S. Mandal’s


AURANGABAD




G.S. Mandal’s

MAHARASHTRA INSTITUTE OF TECHNOLOGY,AURANGABADDEPARTMENT OF MECHANICAL

ENGINEERING

NAME OF LABORATORY:MATERIALS AND METALLURGY

LABORATORY MANUAL

CLASS: THIRD YEAR PART: I COURSE CODE :MED 322

NAME OF COURSE : MATERIALS AND METALLURGY

PREPARED BY: Prof. P. A. Lad APPROVED BY: Dr., A. J. Keche (HMED) 2

INDEX

Sr. No.

Contents Page No.

1 Vision & Mission of Institute 3

2 Vision & Mission of Department 4

3 Program Educational Objectives 5

4 Program Outcomes 6

5 Program Specific Outcomes 8

6 Course Objectives & Course Outcomes 9

7 University Syllabus 10

8 Lab Instructions 11

9 Measurement of hardness by Rockwell hardness test. 12

10 Study of mechanical properties like tensile strength, impact strength and wear

resistance of materials. 18

11 Study of metallurgical microscope 24

12 Study of preparation of the specimen for microscopic examination. 30

13 Observation of microstructure of various types of Plain carbon steels and

Alloy steels. 35

14 Observation of microstructure of various types of Cast Iron. 41

15 Observation of microstructure of various types of Nonferrous Alloys 44

16 Study of changes in material properties and microstructures after Heat

treatments like Annealing, Hardening, Tempering, Cryogenic Treatment, etc. 48

17 Study of Jominy end quench test to understand the concept of Hardenability. 53

18 Study of Nanomaterials and Nanocomposites. 57

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Vision:

MIT aspires to be a leader in Techno-Managerial education at national level by developing

students as technologically superior and ethically strong multidimensional personalities

with a global mindset.

Mission:

We are committed to provide wholesome education in Technology and Management to

enable aspiring students to utilize their fullest potential and become professionally

competent and ethically strong by providing,

Well qualified, experienced and Professionally trained faculty

State-of-the-art infrastructural facilities and learning environment

Conducive environment for research and development.

Delight to all stakeholders.

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Vision of Mechanical Engineering Department

To be a center of excellence in the field of Mechanical Engineering where the best of

teaching, learning and research synergize and serve the society through innovation and

excellence in teaching.

Mission of Mechanical Engineering Department

To provide world-class under-graduate and graduate education in Mechanical

Engineering by imparting quality techno-managerial education and training to meet current

and emerging needs of the industry and society at large.

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Program Educational Objectives (PEOs):

PEO 1 Graduates will apply the tools and skills acquired during their undergraduate

studies either in advanced studies or as employees in engineering industries.

PEO 2 Graduates of the program will have successful technical and professional career.

PEO 3 Graduates of the program will continue to learn to adopt constantly evolving

technology.

PEO 4 Graduates will demonstrate sensitivity towards societal issues.

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Program Outcomes:

POs Description PO 1 Engineering

Knowledge Apply the knowledge of mathematics, science, engineering

fundamentals, and an engineering specialization to the

solution of complex engineering problems.

PO 2 Problem Analysis Identify, formulate, review research literature, and analyze

complex engineering problems reaching substantiated

conclusions using first principles of mathematics, natural

sciences, and engineering sciences.

PO 3 Design / Development of Solutions

Design solutions for complex engineering problems and

design system components or processes that meet the

specified needs with appropriate consideration for the public

health and safety, and the cultural, societal, and

environmental considerations

PO 4 Conduct Investigations of Complex Problems

Use research-based knowledge and search methods

including design of experiments, analysis and interpretation

of data, and synthesis of the information to provide valid

conclusions.

PO 5 Modern Tool Usage

Create, select, and apply appropriate techniques, resources,

and modern engineering and IT tools including prediction

and modeling to complex engineering activities with an

understanding of the limitations.

PO 6 The Engineer and Society

Apply reasoning informed by the contextual knowledge to

assess societal, health, safety, legal and cultural issues and

the consequent responsibilities relevant to the professional

engineering practice.

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PO 7 Environment and Sustainability

Understand the impact of the professional engineering

solutions in societal and environmental contexts, and

demonstrate the knowledge of, and need for sustainable

development.

PO 8 Ethics Apply ethical principles and commit to professional ethics

and responsibilities and norms of the engineering practice.

PO 9 Individual and Team Work

Function effectively as an individual, and as a member or

leader in diverse teams, and in multidisciplinary settings.

PO 10 Communication Communicate effectively on complex engineering activities

with the engineering community and with society at large,

such as, being able to comprehend and write effective

reports and design documentation, make effective

presentations, and give and receive clear instructions.

PO 11 Project Management and Finance

Demonstrate knowledge and understanding of the

engineering and management principles and apply these to

one’s own work, as a member and leader in a team, to

manage projects and in multidisciplinary environments.

PO 12 Life-long Learning

Recognize the need for, and have the preparation and ability

to engage in independent and life-long learning in the

broadest context of technological change.

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Program Specific Outcomes:

PSO 1 Ability to design &analyze components & systems for mechanical performance

PSO 2 Ability to apply and solve the problems of heat power and thermal systems

PSO 3 Ability to solve real life problems with the exposure to manufacturing industries

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Course Objectives:

1. Introduce students to the field of materials science and materials testing.

2. To understand various types of phase diagrams their applications.

3. To understand principle of various Heat Treatments.

4. To understand classification of Alloy Steels and cast iron.

5. To introduce latest materials in manufacturing

Course Outcomes:

CO Code Statement

CO 1 MED 352.1 Remember the types of Materials, Mechanical properties and Crystal structure of materials.

CO 2 MED 352.2 Understand the different types of phase diagrams and equilibrium diagram.

CO 3 MED 352.3 Describe the microstructure of different types of metals and alloys.

CO 4 MED 352.4 Distinguish between the properties and application of different types of metals and alloys.

CO 5 MED 352.5 Illustrate between various types of heat treatment processes and their effects on steel structure and properties.

CO 6 MED 352.6 Discuss about smart materials, composites and nanomaterials.

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University Syllabus:

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Lab Instructions

1. College uniform, shoes are compulsory in the lab.

2. Student should wear college ID-card and must carry record and observation.

3. Take signature of lab in charge after completion of observation and record.

4. If any equipment fails in the experiment report it to the supervisor immediately.

5. Students should come to the lab with thorough theoretical knowledge.

6. Don't touch the equipment without instructions from lab supervisor.

7. Don't crowd around the experiment and behave in-disciplinary.

8. Students should carry their own stationary and required things.

9. Using the mobile phone in the laboratory is strictly prohibited.

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EXPERIMENT NO. 1

Aim: Measurement of Hardness by Rockwell Hardness test

Objectives:-

1. To understand the concept of hardness.

2. To conduct and measure typical engineering hardness tests on different materials.

3. To study behavior of materials using hardness test.

Apparatus: Rockwell hardness tester, Indenters, etc.

Table no 1.1 Standard Rockwell hardness scale and their specification

Scale

Symbol

Indenter Major

Load(kg)

Dial

Numerical

Typical Application of Scale

Remark

B 1/6" Ball 100 Red Brass, Low and medium carbon

steel in annealed and normalized

condition.

C Blade 150 Black Hardened steel, Hard C.I., Deep

case hard steel.

A Blade 60 Black Hard thin material like blade, Case

hardened steel and surface centered

carbide.

D Blade 100 Black Used where major load is desired

between those required for A and C.

F 1/8" Ball

(32mm)

100 Red Used for measuring hardness of

very safe material such as ferrite

material, aluminum and its alloy etc.

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Theory:

In this method hardness of metal is correlated with the depth of indentation and does

not with area of indentation as in Brinell hardness and vice versa. The dial is calibrated in an

inverse fashion, so that the hardness number becomes directly proportional to hardness of

material. In this test there are 2 types of indenters are used:

1. Hard steel ball of 1/6", 1/8", 1/4" and 1/2" diameter

2. Brale indenter made of diamond in form of cone with include angle of 120O, the tip of

indenter is accurately grounded to radius of 0.2mm.

Loads are applied in 2 stages:

1. A constant minor load of 10kg is applied.

2. Then major loads are applied of 60, 100 or 150kg.

The Various combination of indenters and loads are indicated by letter such as a, b, c etc. The

complete list is given in table. In all there are 15 combinations. A letter indicates 60kg load

and Brale indenter. B letter indicates C letter indicates 150kg load and Brale indenter and so

on. Few of application of each scale are given in table 1.1.

Procedure:-

The method of testing is illustrated in figure by taking a standard 1/6" diameter ball

indenter and 100kg major load "B-scale". The size of ball is exaggerated in the figure for

better illustration of penetration distance by minor and major load.

The test is carried out as bellow:

1. The specimen surface on which hardness is to be measure should be free from dust

and surface defects. The specimen is placed on the anvil, the dial pointers are ideal major or

minor load is applied. The anvil along with the specimen is raised, then so that the specimen

touches the indenter. By further raising the anvil slowly, the minor load of 10kh is applied. At

this stage the small pointer on dial co-inside with number 3 and big dial co-inside with zero

pointed with black ink or 30 mark pointer in red ink or set point marked on dial.

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If the large pointer is not at this position, the barrel of dial is then rotated until zero or 30 or

set point mark co-inside with large pointer. The minor load of 10k has forced the indenter into

the specimen to a depth up to B (A to B).

2. In this step, since load is an opposite direction, the large pointer moves in clockwise

direction during the penetration of indenter.

3. Major load of 100kg is applied by means of a release handle provided on right side of the

instrument. This load is applied gradually by means of a dashpot arrangement. The major load

of 100kg consists of original minor load of 10kg plus an additional load of 90kg. The

application of major load forced the ball into specimen to additional depth up to C (B to C).

Due to this large pointer move in counter clockwise direction from set point, corresponding to

(B to C) the depth of penetration

(100-40) X 0.002 =0.12 mm

4. Without removing the minor load of 10kg, the major load of 90 out of 100kg is removed.

Due to this elastic recovery depth comes to D point.

5. Without removal of minor load hardness No. read directly from dial which is 60 in figure.

This hardness is designation of RB = 60 RHN.

6. The minor load of 10kg is removed and next reading is taken on same specimen at different

place in way similar to above. The scale of dial with respect to the motion of pointer is

reversed so that shallow and deeper indication indicate a lower hardness No.

The calibration is according to the following equation:

A) For Brale indenter: RHN = 100 - (Depth of penetration in mm/0.002)

B) For ball indenter: RHN = 130-(Depth of penetration in mm/0.002)

TECHNOLOGY,AURANGABAD


LABORATORY MANUAL

CLASS: THIRD YEAR

NAME OF COURSE : MATERIALS

PREPARED BY: Prof. P. A. Lad

Table no 1.2 Scale symbol for various combinations of load and

Indenter

Cone (Brale) 1/6" Ball 1/8" Ball 1/4" Ball 1/2" Ball

Figure 1.1 Procedure of Rockwell Hardness Test

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PART: I COURSE CODE :


APPROVED BY: Dr., A. J. Keche (HMED)

Scale symbol for various combinations of load and ball diameter:

Major Load(kg) 60 100 A D F B H E L M R S

Figure 1.1 Procedure of Rockwell Hardness Test

DEPARTMENT OF MECHANICAL

RSE CODE :MED 322


ball diameter:

150 C G K P V

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Observation:

Table no. 1.3 Observations Table

Sr.No Material

to be

Tasted

Load(kg) Indenter Scale Dial Reading

1

2

3

4

5

6

Advantages of Test:

1. Since both type of indenter are used i.e. steel ball and diamond cone, it combines

advantages of Brinell and Vickers’s hardness test and also eliminates the back draw of this

test. Brale indenter is used for testing of the hard material and indenter used for testing of soft

and heterogeneous material. Due to this testing of all types of material is possible by proper

selection of indenter.

2. Thick as well as thin (no very thin) material can be tested 60kg major load is applied for

thin material and 100kg for thick material.

3. Surface condition of the component to be testes is not so critical because the hardness No.

is correlated to difference of depth from minor load top major load.

4. The operator needs very little training for operating this instrument and hence a new

operator can be trained in short time.

5. The test is very fast and require less time.

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Precautions:

1. For testing cylindrical test specimen, use V-type platform.

2. Calibrate the machine occasionally using standard test blocks.

3. After applying Major load, wait for some time to allow the needle to come to rest.

4. The waiting time vary from 2 to 8 seconds.

5. The surface of the test piece should be smooth and even and free from oxide scale

and foreign matter.

6. Test specimen should not be subjected to any heating or cold working.

7. The thickness of test piece or of the layer under test should be at least 8 times the

permanent increase of depth of “E”.

8. The distance between the centers of two adjacent indentations should be at least 4

indentations to the edge of the test piece should be at least 2.5 times the diameter of

the indentation.

Results: -

Conclusions:

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EXPERIMENT NO: - 2

Aim: - To Study Mechanical properties like tensile strength, impact strength and wear resistance of materials.

Objectives:-

i. To Study a tensile strength of a material.

ii. To measure the Impact Strength of material

iii. To study wear testing of material.

Theory:-

THEORY: The tensile test is most applied one, of all mechanical tests. In this test ends of test

piece are fixed into grips connected to a straining device and to a load measuring device. If

the applied load is Universal Testing Machine 3 | P a g e M T L a b C C - D .S . D h a k a

small enough, the deformation of any solid body is entirely elastic. An elastically deformed

solid will return to its original from as soon as load is removed. However, if the load is too

large, the material can be deformed permanently. The initial part of the tension curve which is

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recoverable immediately after unloading is termed. As elastic and the rest of the curve which

represents the manner in which solid undergoes plastic deformation is termed plastic. A

tensile test, also known as a tension test, is one of the most fundamental and common types of

mechanical testing. A tensile test applies tensile (pulling) force to a material and measures the

specimen's response to the stress. By doing this, tensile tests determine how strong a material

is and how much it can elongate. Tensile tests are typically conducted on universal testing

instruments, are simple to perform, and are fully standardized. By measuring the material

while it is being pulled, we can obtain a complete profile of its tensile properties. When

plotted on a graph, this data results in a stress/strain curve which shows how the material

reacted to the forces being applied. The point of break or failure is of much interest, but other

important properties include the modulus of elasticity, yield strength, and strain.

Ultimate Tensile Strength

One of the most important properties we can determine about a material is its ultimate

tensile strength (UTS). This is the maximum stress that a specimen sustains during the test.

The UTS may or may not equate to the specimen's strength at break, depending on whether

the material is brittle, ductile, or exhibits properties of both. Sometimes a material may be

ductile when tested in a lab, but, when placed in service and exposed to extreme cold

temperatures; it may transition to brittle behavior.

Hooke's Law

For most materials, the initial portion of the test will exhibit a linear relationship

between the applied force or load and the elongation exhibited by the specimen. In this linear

region, the line obeys the relationship defined as "Hooke's Law" where the ratio of stress to

strain is a constant, or . E is the slope of the line in this region where stress (σ) is proportional

to strain (ε) and is called the "Modulus of Elasticity" or "Young's Modulus."

Modulus of Elasticity

The modulus of elasticity is a measure of the material's stiffness which only applies in the

initial linear region of the curve. Within this linear region the tensile load can be removed

from the a specimen and the material will return to the exact same condition it had been in

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prior to the load being applied. At the point when the curve is no longer linear and deviates

from the straight-line relationship, Hooke's Law no longer applies, and some permanent

deformation occurs in the specimen. This point is called the "elastic or proportional limit.

From this point on in the tensile test, the material reacts plastically to any further increase in

load or stress. It will not return to its original, unstressed condition if the load is removed.

Yield Strength

A material's "yield strength" is defined as the stress applied to the material at which

plastic deformation starts to occur.

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Impact Test

THEORY: - In manufacturing locomotive wheels, coins, connecting rods etc. the

components are subjected to impact (shock) loads. These loads are applied suddenly. The

stress induced in these components are many times more than the stress produced by gradual

loading. Therefore, impact tests are performed to determine shock absorbing capacity of

materials subjected to suddenly applied loads. These capabilities are expressed as (i) Rupture

energy (ii) Modulus of rupture and (iii) Notch impact strength.

Two types of notch impact tests are commonly

1. Charpy test

2. Izod test

1. Izod test: -

In Izod test, the specimen is placed as ‘cantilever beam’. The specimens have V-

shaped notch of 45°. The notch is located on tension side of specimen during impact loading.

Depth of notch is generally taken as t/5 to t/3 where ‘t’ is thickness of the specimen.

2. Charpy Test

In charpy test, the specimen is placed as ‘horizontal beam’. The specimens have V-shaped

notch of 45°. U-shaped notch is also common. The notch is located on tension side of

specimen during impact loading.

Diagram

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Wear Test:

Aim: To study the wear resistance property of materials-steel, brass and aluminum using pin-

on disc wear testing machine.

Theory: Wear is the progressive loss of substance from the operating surface. The usual

classification of types of wear is abrasive wear ; most examples in practice are a combination

of two or more of these. “Abrasive wear”– abrasion is virtually a cutting action which may

result from loose, hard particles sliding between two mating surfaces. It can also arise when

one pair of rubbing surfaces is itself rough. The loose particles may be dirt from the

environment or wear debris.

Adhesive wear:

If a tangential force is applied between two sliding blocks, shearing can take place

either at the original interface or along a path below or above it, causing adhesive wear.

Adhesive wear arises when junctions weld together, becomes broken by relative motion and

wear particle result . In the case of a steel shaft rotating in a broken bearing , it is not

uncommon to find traces of broken film on the shaft thus indicating adhesive wear. Fretting

wear: When a small relative slipping motion takes between two surfaces the result is an

amount of fine wear debris and this wear is designated as fretting wear.

Fatigue wear:

Wear due to dynamic loading is called fatigue wear. Balls and rollers are subject to

very high alternating stresses and when these are above the endurance limit, small cracks will

result followed by pitting and spalling. Erosive wear: Wear due to impact of particles is called

erosive wear. A popular example is sand blasting

There are several testing materials for measure of wear. The simplest is pin on disc machine in

which a loaded pin is pressed on to rotating disc. The amount of wear after a given amount of

rubbing is measured either by loss of weight of specimen or dimensional changes.

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Practical Importance:

The primary object of most wear studies is to reduce wear . Wear may result whenever

there is relative sliding. The rate at which material is removed will depend on working

conditions. E.g. Loading, lubrication and environment.

Wear studies are of immense use in study of:

1) Wear in reciprocating engine.

2) Wear in sleeve bearing, ball bearing and roller bearings

3) Wear in cam and tappet wear.

4) Wear of tires.

5) Wear of gears of machinery.

6) Wear of cutting tools etc., Surface treatment like plating, nitriding , carburizing and

hardening and etc., are given to reduce wear , wear may also be reduced by good design and

proper selection of materials.

Results:-

Conclusion:-

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EXPERIMENT NO: - 3

Aim: - To Study Metallurgical Microscope

Objectives:-

To be acquainted with the Operation, Construction, application and capabilities of a

Metallurgical Microscope.

Apparatus: - Optical Microscope

Specification Inverted Metallurgical Microscope

Objective Plan Achromatic(up to 40x)objective 10x/0.25 (W.D = 8.9mm) 20x/0.40 (W.D = 0.72mm) 40x/0.60 (W.D = 0.67mm) 60x/0.75 (W.D = 0.35mm) 100x/0.85 (W.D = 0.25mm)

Plan eyepieces 10x (field of view : 16mm) 16x (field of view : 11mm) 20x (field of view :9mm)

Stage Square movable mechanical stage, size : 200m x 152mm Movable range 15mm x 15mm

Illumination system

Koehler illumination system with 6v. 20W halogen build or LED light intensity are adjustable

Filter With yellow, green and Blue filters Other Coaxial coarse and fine adjustment system with security stopper.

Eyepiece with micrometer (optional) 10x with minimum division 0.1mm

Theory: -

The metallurgical microscope is the most important tool of the metallurgist. It consists

of an objective & an eye-piece. Its primary function is to reveal the details of the object. he

clarity & the extent to which their optical system are created.

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Principle: -

A Horizontal beam of light froth light source is reflected by means of a plane gas

reflector downwards through the microscope objective on the surface of the specimen some of

this incident light reflected from the specimen surface will be magnified & passing through

the plane glass reflector & magnified again by upper lens system of the eye-piece.

Construction Details: -

Parts of Metallurgical Microscope

1. Stage: A flat movable table supporting specimen. This can be moved up or down by knobs

2. Tubes: The vertically movable tube containing eye-piece, objective & plane reflector. The

tube length varies from 160mm to 250mm.

3. Illuminating System: It used to light up the surface of the specimen under examination. It

consists of a light source/aperture, diaphragm a slot for fillers & a plane glass reflector. A

horizontal beam of light from the source is divided by the pain glass reflect downwards &

through microscope objective to the surfaces of specimen. A certain amount of this incident

light is reflected from the specimen surface and passes through the objective in the eyepiece

an enlarge ass the illuminated area of the specimen surface is observed by looking through the

eyepiece. The aperture diagram in the illuminating system controls the angular aperture of the

cone of light rays which is used to illuminate the specimen from the image. The optimum

opening of the diaphragm should be used, which depends upon the objectives being used for

satisfactory illumination; the angle of the plane glans reflector should be adjusted.



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CLASS: THIRD YEAR



Figure 2.1 Optical system of Metallurgical Microscope

4. Objective Lens:-

The objective lens system which forms the primary image of

important of the microscope. The major function of an objective lens is to collect the

maximum quantity of light coming from any point on the specimen. and combine it into an

image. The ability to collect light is determined by t

NA =𝜇𝑠𝑖𝑛𝛼

Where,

NA = Numerical aperture of the objective.

𝜇 = Reflective index of the medium between the sp

𝛼 = Half of angle of the most oblique rays entering front lens of objective.

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Figure 2.1 Optical system of Metallurgical Microscope

The objective lens system which forms the primary image of the specimen is the most



image. The ability to collect light is determined by the numerical aperture of the objective.

Numerical aperture of the objective.

= Reflective index of the medium between the specimens of objective lens.

= Half of angle of the most oblique rays entering front lens of objective.


RSE CODE :MED 322


the specimen is the most



he numerical aperture of the objective.

Numerical aperture of the objective.

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Numerical aperture of the objective increase𝜇 &𝛼 . The value of refractive index for an air

objective lens is 1.0 and 1.5. Numerical aperture for the objective varies from 0.5 to 1.32.

The most important property of an objectives lateral solution which may be defined as

the ability to see very small object or to revolve to objects very close together. The limit of

resolutions i.e. the minimum distance which may be just resolved is given by.

Resolution limit = 0.5 to 0.61 λ

NA

Where,

λ = Wavelength of radiation.

Therefore, the resolution of an optical microscope is directly dependent upon the numerical

aperture of objective once this limit of resolution has been reached, there is no use in

increasing the magnification of system since, no extra details will be revealed. Another term

used has a measure of resolution is the resolving power which is the reciprocal of the limit of

the resolution.

Hence,

Resolving Power = 2NA / λ

Another important property of an objective is its magnification. All objective lenses

are positive lens system i.e. they passes the ability to magnify an object without any additional

optical accessories. The magnifying power of an objective is written on the less mount along

the numerical aperture.

The total magnification of the objective lens and eyepiece i.e. (Mt = Mo. Me)

Where,

Mt = Total magnification.Mo = Objective magnification Me = Eyepiece magnification.

Ideally, all that an optical microscope resolves can be seen at magnification of about 500.

Higher magnification makes the detail easier to see but does not increase the resolution.

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5. Eyepiece: - A removable eyepiece is fitted to an adjustable draw tube of the microscope.

By approximately positioning the primary real image with respect to the eyepiece the primary

image upon can be further enlarged depending upon the magnifying power of eyepiece

magnification are 5x, 7x, 10x, 5x, etc.

Microscope Technique: - Most of the microscopic studies of metal are made using bright

filled illumination. In addition to these types of illumination, several special techniques, such

as oblique illumination dark -field illumination, opaque-stop microscopy, and phase contrast

microscopy and polarized contrast microscopy and have particular application for

metallographic studies. In addition to these techniques 10W, high temperature microscope

work can also be done using different attachments to the microscope.

Electron Microscope: - A breakthrough in metallographic has been achieved through the

development of an electron microscope. It is capable of achieving much greater resolution

power and higher magnification then that obtains in optical microscope. A modern electron

microscope is capable of giving magnification from 104 to 106 diameters for optical

microscope. The resolution obtainable with electron microscope is of order of 0.0002μ.

Working Principle:-

The electron microscope uses electron to illuminate the specimen in an electron

microscope, an image of the contour of specimen surface is formed by converging a stream of

rapidly moving electron after passing through a thin section of specimen or of transparent

replica. The beam of electron trade incident on specimen originates from cathode ray

discharge tube operated at 50 to 1000 KW. The beam of electron is focused by passing

through a series of electron magnetic lens. It is used in vacuum to give sufficiently long free

path for electrons.

Results:-

Conclusions:-

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EXPERIMENT NO: - 4

Aim: Study of preparation of the specimen for Microscopic Examination

Objective:

To learn the preparation of specimen for Microscopic examination

Apparatus:

1. Abrasive cut off wheel

Absolute minimal deformation, cool & burn-free sample production

Effortless cutting by lever mechanism, counter balancing

Robust construction and rigid clamping minimizing wheel breakage.

Large and Effective coolant delivery by unique design of casted wheel guard

with focused vains.

Control Panel incorporates door limit switch, emergency stop, illumination

on/off & machine-on, switches.

Indications of door open, power on pump on. Covering other safety norms.

Dedicated wheels for very hard, medium hard, soft components and universal

wheel, in 10 “, 12 " & 14 ", thickness 1.5mm,2mm,3mm,hole sizes 1" or

1.25",(Al2O3).

2. Specimen

3. Hot specimen mounting press

Just press a button and get the mould

Reliable microcontroller based technology offering complete automation like pressing ,heating, holding, cooling(water circulation)

Transparent mould capability enabling seeing identification mark.

Easy mould interchangeability.

Fast mould production.

Mould produced – 1” ,11/4” ,11/2”

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Heater – 1000 Watts

Cooling automatic water circulation.

Air pressure required 150 PSI

Electrical supply- single phase. 4. Thermosetting powder 5. Belt Grinder

Table No. 3.1 Specification of Belt Grinder Motor ¼ HP motor OR 1 HP motor, 220 AC, 60 Hz ,

Single phase

Belt driving roller Dia. 100 mm.

Belt dimensions 100 x 915 mm , Medium or fine grade

Housing

Sheet metal, side panel in built sink, water faucet

arrangement with inlet and outlet hope pipe

nipples’.

6. Double disc polishing machines

Table No. 3.2 Specification of Belt Grinder

Disc diameter 200 mm

Motor Capacity ½ HP or 1 HP

Net Wt. 45 Kg

Supply 5 Amps, 230 V, Single phase

Speed 1400 rpm

Other Digital rpm indicator

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Theory:-

The credit for originating Metallographic examination goes to Alloys BeckVon

Widmanstatten (between 1808 & 1840). Microscope was employed for the purpose in 1841,

when Paul Ann sow used the instrument to examine the etched surfaces of oriental steel

blades. It was around 1890 when metallographic technique received general recognition,

largely as a result of the work of Professor Henry C. Sorby in England.

Metallography is the general study of metals and their behavior, with particular

reference to their microstructure and macrostructure.

Microstructure is the characteristic appearance and physical arrangement of metal

molecules as observed with a microscope.

Macrostructure is the appearance and physical arrangement as observed with the

naked eye.

Metallurgical Microscopeis by far the most important tool of the metallurgist from

both the scientific and technical stand point. It helps determining:

a) Grain size and shape.

b) Size, shape and distribution of various phases and inclusion.

c) Mechanical and thermal treatment of the alloys.

The mounting press consists of top plate and bottom plate with movable center stage

plate which is moving up and down along the guide ways. The middle part is raised and

lowered by hydraulic jack. The mould part is the space between the guide ways. Its

temperature is controlled by a knob. A digital timer is also provided on the panel to maintain

the constant temperature of the mould for a certain period of time.

In belt polishing machine, an endless belt rotates between two shafts. In plate

polishing machine different grades of emery papers are placed on the stand. In disc polishing

machine emery cloth is placed over the two rotating plates.

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Procedure:-

Preparation of Specimen:

Preparation of specimen is necessary to study its microstructure, because the metallurgical

microscope discussed earlier makes use of the principle of reflection of light from the

specimen to obtain the final image of the metal structure. Following are the steps involved in

the preparation of specimen:

1) Selection of specimen: When investigating the properties of a metal or alloy, it is essential

that the specimen should be selected from that area (of the alloy plate or Casting) which can

be taken as representative of the whole mass.

2) Cutting of the specimen: After selecting a particular area in the whole mass, the specimen

may be removed with the help of appropriate cutting tools. The specimen is cut by abrasive

cut off machine.

3) Mounting the specimen: If the specimen is too small to be held in hand for further

processing, it should be mounted on a thermoplastic resin disc or some other low melting

point alloy. Specimen is placed in the desired position preferably at the Centre of the mould.

Bakelite powder is poured up to the required level. The spindle is tightened. Switch ON the

power supply. Press the mould using ram. Switch on heater button. The process is started by

pressing process button on mounting press. When desired temperature is reached near about

100oC to 110oC in the digital display first buzzer will start then switch of the first buzzer.

Again second buzzer will start, press the reset button and start water supply. When temp

reaches to 80 degree reset the button and after three to five minutes takes out the mounted

specimen from the mould. Finally the specimen is mounted in the thermosetting material.

4) Obtaining flat specimen surface: It is first necessary to obtain a reasonably flat surface on

the specimen. This is achieved by using a fairly coarse file or machining or grinding.

5) Intermediate and Fine Grinding: Intermediate and fine grinding is carried out using

emery papers of progressively finer grade.

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6) Rough polishing:A very small quantity of diamond powder (particle size about 6microns)

carried in a paste that is oil-soluble is placed on the nylon cloth-covered surface of a rotating

polishing wheel. The specimen is pressed against the cloth of the rotating wheel with

considerable pressure and is moved around the wheel in the direction opposite to rotation of

the wheel to ensure a more uniform action.

7) Fine polishing: The polishing compound used is alumina (Al2O3) powder placed on a cloth

covered rotating wheel. Distilled water is used as a lubricant. Fine polishing removes fine

scratches and very thin distorted layer remaining from the rough polishing stage.

8) Etching:Necessity-Even after fine polishing, the granular structure in a specimen

usuallycannot be seen under the microscope; because grain boundaries in a metal have a

thickness of the order of a few atom diameters at best, and the resolving power of

amicroscope is much too low to reveal their presence.In order to make the grain boundaries

visible, after polishing the metal

Specimens are usually etched. Etching imparts unlike appearances to the metal constituents

and thus makes metal structure apparent under the microscope. Method- Before etching, the

polished specimen is thoroughly washed in running water. Then, the etching is done either by,

(i) Immersing the polished surface of the specimen in the etching reagent or by

(ii) Rubbing the polished surface gently with a cotton swab wetted with the etching reagent.

After etching, the specimen is again washed thoroughly and dried. Now, the specimen can be

studied under the microscope.

Precautions:

Pressure should be applied uniformly

The specimen should be placed at the Centre of the mould

Heat the specimen uniformly

Results:

Conclusions:

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EXPERIMENT NO: 5

Aim: Preparation and Study of Microstructures of Plain Carbon Steel.

Objectives:

1. To learn the preparation of specimen for microscopic observation.

2. To understand the microstructures of different steels.

3. To study the microstructures of different steels.

4. To study the differences in microstructure of different type of cast irons.

Apparatus: (Specifications details given in Exp.No.2 &3)

Given specimen

Consumables

Belt grinder

Emery papers (80,120,240,400,600)

Disc polishing machine

Microscope

Theory:

Iron-Carbon Diagram

In their simplest form, steels are alloys of Iron (Fe) and Carbon (C). The Fe-C phase diagram

is a fairly complex one, but we will only consider the steel part of the diagram, up to around

7% Carbon.

Phases in Fe–Fe3C Phase Diagram

1. α-ferrite -solid solution of C in BCC Fe

• Stable form of iron at room temperature.

• The maximum solubility of C is 0.022 wt.%

• Transforms to FCC γ-austenite at 912 °C

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2. γ-austenite -solid solution of C in FCC Fe

• The maximum solubility of C is 2.14 wt. %.

• Transforms to BCC δ-ferrite at 1395 °C

• Is not stable below the eutectic temperature (727 °C) unless cooled rapidly.

3. δ-ferrite solid solution of C in BCC Fe

• The same structure as α-ferrite

• Stable only at high T, above 1394 °C

• Melts at 1538 °C

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4. Fe3C (iron carbide or cementite)

This intermetallic compound is metastable, it remains as a compound indefinitely at

room T, but decomposes (very slowly, within several years) into α-Fe and C (graphite) at 650

-700 °C

5. Fe-C liquid solution

A few comments on Fe–Fe3C system C is an interstitial impurity in Fe. It forms a

solid solution with α, γ, δ phases of iron Maximum solubility in BCC α-ferrite is limited

(max. 0.022 wt.% at 727 °C) -BCC has relatively small interstitial positions Maximum

solubility in FCC austenite is 2.14 wt.% at 1147 °C-FCC has larger interstitial positions

Mechanical properties: Cementite is very hard and brittle can strengthen steels. Mechanical

properties also depend on the microstructure, that is, how ferrite and cementite are mixed.

Magnetic properties: α -ferrite is magnetic below 768 °C, austenite is non-magnetic.

Plain carbon steels are steels having carbon as the predominant alloying element and

the other alloying elements are either Nil or negligible though some amount of Sulphur and

phosphorous are present. Normally the amounts are less than 0.05 percent and hence they are

not considered. The plain carbon steels are broadly classified in to low carbon steels with

carbon content less than 0.3 percent and medium carbon steels contains Carbon with 0.3 to

0.7. The high carbon steels contain carbon from 0.7 to 1.5 percent.

Procedure:

Step 1: The specimens of pure metals like Mild steel, Low carbon steel and high carbon steels

are mounted in a thermosetting material as explained in the experiment no. 1.

Step 2: Polish the specimen by using (80,120,240,400and 600) grade emery papers. Subject

the given specimen to mirror like finish by using disc polishing machine and with suitable

abrasive.

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Step 3: Clean the specimen with alcohol and wash it under the stream of flowing water. After

washing the specimen is dried.

Step 4: After drying apply the suitable etching agent for 30 to 60 sec.

Step 5: After etching wash the specimen under the stream of flowing water. Dry the specimen

with the help of air blower.

Step 6: Place the specimen under the microscope for metallurgical studies. Draw the micro

structure and identify the material for the given specimen.

Low Carbon Steel:

As the microstructure shows the structure of the mild steel, it contains 25% pearlite

and 75% ferrite. The dark region defines the pearlite and bright portion is of ferrite. The

properties of low carbon steels are the material is soft and ductile It is easily weld able. It is

cold workable.The tensile strength varies from 390 to 550 N/ mm^2 The Brinell hardness

number varies from115 to 140. The application includes making steel wire, sheets, rivets,

screws, pipe chain and structural parts.

Medium Carbon Steel:

The microstructure reveals two phases are to be about 50% each. Hence the carbon

content can be accessed to be equal to it. The properties of medium carbon steels are

invariably between low and high carbon steels. The tensile strength varies between 75 to 800

N/ mm2 The medium carbon steels are used in manufacture of drop forging dies, die block

plates, punches, screws and valve springs etc.

High Carbon Steel:

Microstructure of high carbon steels consists of continuous network of cementite in

matrix to pearlite. This cementite structure is hard and brittle and hence has poor

machinability. As carbon content increases weldability, cold working decreases. They have

high strength and hardness. Its Tensile strength is up to 1400 N/mm2 hardness varies from

450 to 500 BHW. High carbon steels are used in cutting machine tools, manufacturing cold

dies and wheels for railways.

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Observations:

Precautions:

1. Polishing should be slow, sooth and flat.

2. Uniform pressure is applied throughout the polishing.

3. CLEANLINESS!!! Keep the room and the work areas.

4. Don't touch etched and polished surface of the specimen.

5. Don't touch the lances of eyepiece with dirty hand.

6. Use clean clothes only to clean the lenses of eyepieces.

7. Handle the microscope with gently.

8. Return the standard specimen to the Lab Technician after observation.

9. Switch off the microscope after the observation.

Results:

Conclusions:

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EXPERIMENT NO: 6

Aim: To identify and draw the microstructures of Cast Iron specimens like Grey Cast Iron,

White Cast Iron, Malleable Cast iron, and S.G. Cast iron etc.

Objectives:


2. To understand the microstructures of different cast irons.

3. To study the microstructures of different cast irons.

4. To learn the differences in microstructure of different type of cast irons.

Apparatus :( Specifications details given in Exp.No.2 &3)

Given specimen

Specially designed files

Belt grinder

Emery papers (80,120,240,400,600)

Disc polishing machine

Microscope

Theory:

Cast irons contain 2 to 6.67 % of carbon. Since high carbon of 2.5 to 4% of carbon, the

ductility of Carbon is very low and it cannot be rolled, drawn or worked at room temperature.

However they melt readily and can be cast to complicated shapes which are usually machined

to final dimensions. Since the casting is only the suitable process applied to these alloys, they

are known as cast irons.

Although the common cast irons are brittle and have lower strength properties than

most steels, they are cheap, can cast more readily than steel and have other useful properties.

In addition by proper alloying good foundry control and appropriate heat treatment is

possible. The properties of any cast iron can be varied over a wide range.

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Procedure:

Polish the specimen by using (80,120,240,400,600) grade emery papers. Subject the

given specimen to mirror like finish by using disc polishing machine and with suitable

abrasive. clean the specimen with alcohol and wash it under the stream of flowing

water

After washing the specimen is dried. After drying supply the suitable etching agent for

30 to 50 sec.

After etching wash the specimen under stream of flowing water.

Dry the specimen with the help air drier.

Place the specimen for metallurgical studies.

Draw the microstructure and analyze the properties

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White Cast Iron:

In white cast iron most of the carbon is present in the combed forms as cementite.This

is obtained by rapid cooling of the iron. White cast irons contains large amount of cementite

as continuous inter dendritic network. It makes the cast iron hard, wear resistance but

extremely brittle and difficult to machine. White cast irons are limited in engineering

applications because of brittleness and lack of machinability. They are used where resistant to

wear is important and service does not require, such as cement mixer, ball mills certain types

of drawing dies and extrusion nozzle. A large tonnage of white cast iron is used as a raw

material for manufacture of malleable cast iron. The composition of typical malleable cast

iron is as follows

Carbon: 2.9% Silicon: 1.15% Manganese: 0.6% Phosphorous: 0.15%Sulphur: 0.5%

Malleable Cast Iron:

In which most of the carbon is uncombined form of irregular particles known as

tempered carbon. This is obtained by heating the white cast iron to 920 to 1000 degree

centigrade for about 50 hours followed by slow cooling to room temperature. While on

heating, the cementite structure tends to decompose in to ferrite plus tempered carbon

(Graphite). The lubrication action of the graphite imports high machinability to malleable cast

iron and lower the melting point makes it much easier to cast than steel. Malleable cast irons

are tough, strong and shock resistant. The addition of copper and molybdenum in combination

produces malleable cast iron of superior corrosion resistance and mechanical properties. The

malleable cast iron is used for wide applications such as agricultural implements, automobile

parts, man whole covers, rail road equipment gears, cams and pipe fittings etc.

Grey Cast Iron:

In which most or all of the carbon is uncombined form of graphite flakes. The

tendency of carbon to form as graphite flakes is due to increased silicon and carbon content

and thereby decreasing the cooling rate.

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It is a low melting alloy, having good cast ability and machinability. It has low tensile

strength, high compression strength and very low ductility. Grey cast iron has excellent

damping capacity and is often used as base for machinery or any equipment subject to

vibration. It is also used for machine tool bodies, pipes and agricultural implements. The

presence of graphite flakes provides lubricating effect to sliding bodies.

The composition of typical grey cast iron is as follows

Carbon: 2.8 to 3.6%

Silicon: 1 to 2.75%

Manganese: 0.4 to 1%

Phosphorous: 0.1 to 1%

Nodular Cast Iron: (Spheroidal Grey Cast Iron)

Nodular cast iron is also known as ductile iron. Spheroidal graphite iron is a cast iron

in which graphite is present as tiny balls or spheroids.

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The compact spheroids interrupt the continuity of the matrix much less than graphite flakes.

This result in higher strength and toughness compared with a similar structure of grey cast

iron. Nodular cast iron differs from malleable cast iron in that it is usually obtained as a result

of solidification and does not require heat treatment. The spheroids are more rounded than

irregular aggregates of temper carbon found in malleable cast iron. The formation of

spherical graphite is due to addition of magnesium to the molten grey iron.

The composition of typical S.G.cast iron is as follows Carbon: 3 to 3.5% Silicon: 2 to

2.5% Manganese: 0.15 to 0.6% Phosphorous: 0.025 to 0.4% Sulphur: 0.015 to 0.04 %

Applications:

Agricultural tractor and implement parts, automotive and diesel crank shafts, piston and

cylinder heads, electrical fittings, motor frames, hoist drums, flywheels and elevator buckets,

steel mill, furnace doors and bearings wrenches levers and handles.

Observations:

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Precautions:









9. Switch off the microscope after the observation.

Results:-

Conclusions:-

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EXPERIMENT NO. 7

Aim: Study of Microstructures of Non-Ferrous Alloys

Objectives:


2. To understand the microstructures of different Non -ferrous alloys.

3. To study the microstructures of different Non -ferrous alloys

4. To learn the differences in microstructure of different type of Non -ferrous alloys.

Apparatus :( Specifications details given in Exp.No.2 &3)

Given Al, Cu alloy specimens

Metallurgical microscope

Suitable etchants

Specially designed files

Belt grinder

Emery papers (80,120,240,400,600)

Double disk polishing machine

Theory:

Nonferrous metals ad alloys contain other than iron as a main constituent. They exhibit

different properties compared to ferrous metals and alloys. Hence their application also differs

from ferrous metals. We shall study the microstructures of Al, Cu, and alloys.

Procedure:

Polish the specimen by using (1/0, 2/0, 3/0, 4/0,) grade emery papers. Subject thegiven

specimen to mirror like finish by using disc polishing machine and with suitable

abrasive. Clean the specimen with alcohol and wash it under the stream of flowing

water.

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After washing the specimen is dried. After drying supply the suitable etching agent for

30 to 50 sec.

After etching wash the specimen under stream of flowing water.

Dry the specimen with the help air drier.

Place the specimen for metallurgical studies.

Draw the microstructure and analyze the properties

Cu- Alloys

Brass:

Brasses are the copper alloys containing zinc up to 30% they possess relatively good

corrosion resistance and good working properties. They also possess high ductility hence they

are suitable for drastic cold working. In common to relieve the stresses annealing is done.

Most normally used brass contains 30% zinc and 70% copper which isknown as cartridge

brass. This shows higher ductility and malleability. The microstructure shows a typical

equiaxed grain structure with twins in annealed structure. This brass is used for making

cartridge cases. Other applications include4s radiator cases, head light reflectors, hardware,

and plumbing accessories.

Al-Alloys:

Aluminum alloy contains silicon up to 12 %. Aluminum- silicon is also called as

silumin. There are two types of aluminum silicon alloys are there.

LM-6:

It contains above 12% silicon due to its higher corrosion resistance and fluidity. It is

Used in water cooled marine tools for pump parts

LM-13

It contains silicon up to 12.5%, Ni 2.5%, ca 1% and Mg 12%. This shows goodforge

ability and low coefficient of thermal expansion. It is used in automobile pistons.

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Bearing Metal:

Bearing metal has high compressive strength and high wear resistance, highfatigue

strength and better thermal conductivity for heat dissipation, corrosion resistance and good

machinability. They have hard and soft phases. Most widely used bearing metal is a Babbitt

metal. They are called as low melting bearing alloy. Lead based ad tin based Babbitt contain

Antimony as most popular this group.

Observations:

Precautions:









9. Switch off the microscope after the observation

Results:

Conclusions:

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EXPERIMENT NO. 08

Aim: Study of changes in material properties and microstructures after Heat treatments like Annealing, Hardening, Tempering, Cryogenic Treatment, etc. Objectives:-

1. To study the different types of the heat treatment process.

2. To study the changes in macrostructure due to heat Treatment.

3. To study the changes in properties of materials after heat treatment process.

Apparatus: Furnace, polish paper, lapping paste, polymeric solution, microscope.

Specification of muffle furnace (MTI-1200)

Chamber- 6 x 6 x 12 Inch. Ceramic Lined.

Max.Temp.12000c, 3 KW,

Heating Element- Kanthal A1 (15 SWG).

Control Panel - Digital controller, Ammeter, Contactor etc.

Theory: Heat Treatment Process

Purpose of Heat Treatment Process:

1. To relief the internal stresses.

2. To reduce hardness and increase ductility.

3. To refine grain quality and make homogenous material.

4. To improve the wear and tear resistance.

5. To improve abrasion resistance.

6. To increase machinability and durability.

Annealing

Annealing is a rather generalized term. Annealing consists of heating a metal to a

specific temperature and then cooling at a rate that will produce a refined microstructure,

either fully or partially separating the constituents. The rate of cooling is generally slow.

Annealing is most often used to soften a metal for cold working, to improve machinability, or

to enhance properties like electrical conductivity.

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Normalizing

Normalizing is a technique used to provide uniformity in grain size and composition

throughout an alloy. The term is often used for ferrous alloys that have been austenitized and

then cooled in open air. Normalizing not only produces pearlite, but also Martensite and

sometimes bainite, which gives harder and stronger steel, but with less ductility for the same

composition than full annealing.

Stress relieving

Stress relieving is a technique to remove or reduce the internal stresses created in a

metal. These stresses may be caused in a number of ways, ranging from cold working to non-

uniform cooling. Stress relieving is usually accomplished by heating a metal below the lower

critical temperature and then cooling uniformly.

Quenching

Quenching is a process of cooling a metal at a rapid rate. This is most often done to

produce a Martensite transformation. In ferrous alloys, this will often produce a harder metal,

while non-ferrous alloys will usually become softer than normal.

To harden by quenching, a metal (usually steel or cast iron) must be heated above the

upper critical temperature and then quickly cooled. Depending on the alloy and other

considerations (such as concern for maximum hardness vs. cracking and distortion), cooling

may be done with forced air or other gases, (such as nitrogen). Liquids may be used, due to

their better thermal conductivity, such as oil, water, a polymer dissolved in water, or a brine.

Upon being rapidly cooled, a portion of austenite (dependent on alloy composition) will

transform to Martensite, a hard, brittle crystalline structure. The quenched hardness of a metal

depends on its chemical composition and quenching method. Cooling speeds, from fastest to

slowest, go from fresh water, brine, polymer (i.e. mixtures of water + glycol polymers), oil,

and forced air. However, quenching certain steel too fast can result in cracking, which is why

high-tensile steels such as AISI 4140 should be quenched in oil.

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Tool steels such as ISO 1.2767 or H13 hot work tool steel should be quenched in forced air,

and low alloy or medium-tensile steels such as XK1320 or AISI 1040 should be quenched in

brine.

Tempering

Untampered martensitic steel, while very hard, is too brittle to be useful for most

applications. A method for alleviating this problem is called tempering. Most applications

require that quenched parts be tempered. Tempering consists of heating steel below the lower

critical temperature, (often from 400 to 1105 ˚F or 205 to 595 ˚C, depending on the desired

results), to impart some toughness. Higher tempering temperatures (may be up to 1,300 ˚F or

700 ˚C, depending on the alloy and application) are sometimes used to impart further

ductility, although some yield strength is lost.

Tempering may also be performed on normalized steels. Other methods of tempering

consist of quenching to a specific temperature, which is above the Martensite start

temperature, and then holding it there until pure bainite can form or internal stresses can be

relieved. These include Austempering and martempering

Flame hardening

Flame hardening is used to harden only a portion of a metal. Unlike differential

hardening, where the entire piece is heated and then cooled at different rates, in flame

hardening, only a portion of the metal is heated before quenching. This is usually easier than

differential hardening, but often produces an extremely brittle zone between the heated metal

and the unheated metal, as cooling at the edge of this heat affected zone is extremely rapid.

Induction hardening

Induction hardening is a surface hardening technique in which the surface of the metal is

heated very quickly, using a no-contact method of induction heating. The alloy is then

quenched, producing a Martensite transformation at the surface while leaving the underlying

metal unchanged.

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This creates a very hard, wear resistant surface while maintaining the proper toughness in the

majority of the object. Crankshaft journals are a good example of an induction hardened

surface.

Case hardening

Case hardening is a thermo chemical diffusion process in which an alloying element, most

commonly carbon or nitrogen, diffuses into the surface of a monolithic metal. The resulting

interstitial solid solution is harder than the base material, which improves wear resistance

without sacrificing toughness.

Laser surface engineering is a surface treatment with high versatility, selectivity and novel

properties. Since the cooling rate is very high in laser treatment, metastable even metallic

glass can be obtained by this method.

Procedure:-

Step 1: Measure the mechanical properties of sample before doing heat treatment process.

Step 2: Observe the microstructure of sample before doing heat treatment process.

Step 3: Place the sample in the furnace and heat the sample in the furnace according to the

heat treatment process.

Step 4: Take out sample from furnace and quench as per heat treatment process.

Step 5: Measure the mechanical properties of sample after heat treatment process.

Step 6: Observe the microstructure of sample after heat treatment process.

Observations:

Results:-

Conclusions:

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EXPERIMENT NO.9

Aim: Study of Jominy end quench test to understand the concept of Hardenability.

Objectives:

1. To understand the concept of Hardenability.

2. To study methods of determination of Hardenability.

Apparatus:

Heat treatment furnace

Jominy end quench apparatus,

Test specimen,

Rockwell test setup

Apparatus Specification details:

Special Furnace with DTC, Thyristor controlled panel avoids temp.

overshooting

At a time three Jominy tests can be carried out.

Quick transfer of specimen to quenching fixture within specific time with the

special tong

Quenching Fixture designed strictly as per BS / SAE with specifications like

45 degree angle of top plate, quenching distance, jet stopper release just before

quenching etc.

Motorized Water Circulation with storage & test tank

Theory:

The various steps involved in evaluating the Hardenability test for a given specimen are as

given below:

a. Determination of hardness no. by Rockwell hardness test

b. Heat treatment in the furnace

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c. Quenching the specimen in Jominy end quench apparatus

a. Determination of hardness No. by Rockwell Hardness Test

The method of determining the hardness consists of measuring the depth of a diamond

cone penetrant that was forced into a metal by applying primary and secondary loads. This

method of measuring hardness significant because errors due to mechanical defects on the

system such as backlash are eliminated ad as well as errors resulting from slight surface

imperfections. The specimen is placed on a suitable anvil on the upper end of the elevation

screw. A minor load of 10 kg is applied by raising the anvil by using elevation screw. Then

apply the major load by using the leaver. After applying the load for a period of 20 sec,

remove the load by turning the lever. Note down the reading on the Rockwell scale.

b. Heat Treatment in the Furnace

Heat treatment is a combination of heating and cooled operations timed and applied to

a metal or alloy so as to produce the desired properties. Heat treated steels amount to about 5

percent of total steel production, but it is indispensable for tools, dies, and a variety of special

purpose steels.

SPECIMEN: Medium carbon (plain Carbon) steel. The percentage of composition is

Carbon 0.35% to 0.45%

Silicon 0.35 %( max)

Manganese 0.60% to 0.8%

Sulphur 0.05 %( max)

Phosphorus 0.05 %( max

c. Quenching the specimen in Jominy end quench apparatus

Take the specimen, place it I the furnace and supply the power. Wait till the

temperature reaches to the Austeniizing temperature. Heat the specimen at the Austeniizing

temperature until it is completely transformed in to Austenite. Remove the specimen from the

furnace with the help of tongs and gloves and place it in the Jominy end quench apparatus and

allow the jet of water to strike one end of the specimen.

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When the specimen reaches to the room temperature remove it from the apparatus and find the

Rockwell hardness at 0.5cms along the length of the specimen. Plot the graph between the

hardness and distance from the quenched end.

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Procedure:

1. Out of the given steel bar, the standard sample is to be prepared as per the dimensions.

2. The Austeniizing temperature and time for the given steel is to be determined

depending on its chemical composition.

3. The furnace is setup on the required temperature and sample is kept in the furnace.

4. The sample is to be kept in the furnace for a predetermined time (based on chemical

composition of steel) then it is taken out of the furnace and is kept fixed in the test

apparatus.

5. The water flow is directed onto the bottom end of the sample. The water flow is

adjusted such that it obtains shape of umbrella over bottom of sample.

6. The quenching is to be continued for approximately 15 minutes.

7. A flat near about 0.4 mm deep is grounded on the specimen. The hardness of the

sample can be determined at various points starting from the quenched end and the

results are tabulated.

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8. The graph is plotted with hardness values versus distance from quenched end. From

the results and graph plotted the depth of hardening of the given steel sample can be

determined.

Observations:

Table 8.1 Observation table for hardness values

Sr.No. Distance from quenched end Hardness

Precautions:

1. The specimen is to be handled carefully while transferring from furnace to test

apparatus.

2. Don’t use the hard water as it leads to formation of scales in nozzles and copper

conduits.

3. Proper water flow (at high pressure) over the bottom end of specimen is to be ensured.

Results:

Conclusions:

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EXPERIMENT NO: - 10

Aim: -Study of properties of Nanomaterials and Nanocomposites.

Theory: -

Nanomaterials can be defined as those materials whose structural element clusters, crystallites

or molecules—have minimum one dimension in the 1 to 100 nm range. Clusters of atoms

consisting of typically hundreds to thousands on nanometer (nm) scale are commonly called

as Nanomaterials. These small groups of atoms, in general, also go by different names such as

nanoparticles, nanocrystals, nanostructures, quantum dotsand quantum boxes. Nanomaterials

can occur naturally, can be created as by-products of combustion reactions or can be produced

purposefully through engineering to perform a specialized function. These materials can have

different physical and chemical properties to their bulk-form counterparts.

Classification of Nanomaterials:

One way to classify Nanomaterials is often dependent upon the number of their dimensions

that are in nanoscale.

1. Zero-Dimensional (0-D): The Nanomaterials with all three dimensions in nanoscale, i.e.

< 100 nm are Zero-Dimensional or 0-D Nanomaterials. These include nanospheres and

nanoclusters.

2. One-Dimensional (1-D): Materials with their two dimensions in the nanoscale are One-

Dimensional or 1-D nanomaterials. This leads to needle shaped materials, however in

nanoscale. Nanofibers, nanotubes, nanorods and nanowires fall under this category.

3. Two-Dimensional (2-D): Here, only one dimension is in nanoscale and other two

dimensions are outside nanoscale. These includenanofilms, nanolayers and nanocoatings

having nanometric thickness.

4. Three-Dimensional (3-D): These are the nanomaterials that are not confined to the

nanoscale in any dimension. These materials have three arbitrary dimensions above 100

nm. The bulk (3D) nanomaterials are composed of a multiple arrangement of nanosize

crystals in different orientations. It includes dispersions of nanoparticles, bundles of

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nanowires and nanotubes as well as multi-nanolayers (polycrystals) in which the 0-D, 1-D

and 2-D structural elements are in close contact with each other and form interfaces.

For the better understanding, nanomaterials are again organized into four types as follows.

1. Carbon based materials: These are composed of carbon, taking the form of hollow

spheres, ellipsoids or tubes. The spherical and ellipsoidal forms are referred as fullerenes,

while cylindrical forms are called nanotubes.



LABORATORY MANUAL

CLASS: THIRD YEAR



2. Metal based materials: A quantum dot is a closely packed semiconductor crystal

comprised of hundreds or thousands of atoms, whose size is on the order of a few

nanometers to a few hundred nanometers.These include quantum dots, nanogold,

nanosilver and metal oxides like TiO

3. Dendrimers: Dendrimers are repetitively branched molecules. The name comes from the

Greek word ‘dendron’ (tree). These nanomaterials are nanosized polymers built from

branched units. The surface of a dendrimer has numerous chain ends,

specific chemical functions. Dendrimers are used in molecular recognition, nanosensing,

light harvesting, and opto-electrochemical devices. They may be useful for drug deliver

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A quantum dot is a closely packed semiconductor crystal



l oxides like TiO2.

Dendrimers are repetitively branched molecules. The name comes from the


branched units. The surface of a dendrimer has numerous chain ends, which can perform


electrochemical devices. They may be useful for drug deliver


RSE CODE :MED 322


A quantum dot is a closely packed semiconductor crystal



Dendrimers are repetitively branched molecules. The name comes from the


which can perform


electrochemical devices. They may be useful for drug delivery.

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4. Composites: Composites are combination of nanoparticles with other nanoparticles or

with larger, bulk-type materials. Nanoparticles like nanosized clays are added to products

(auto parts, packaging materials, etc.) to enhance mechanical, thermal, and flame-retardant

properties.

Nanocomposites:

Results:-

Conclusions:-

Lab Manual - Maharashtra Institute Of Technology

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