mt lab

Department of Industrial Engineering and Management, R.V. College of Engineering, Bangalore 59.

Dept. of Industrial Engineering & Management

Laboratory Manual

Material Testing lab Manual

Edition

2006


Department of Industrial Engineering and Management

R.V. College of Engineering, Bangalore 59

MATERIALS TESTING LABORATORYSCHEME OF CONDUCT AND EVALUATION

CLASS: III SEMESTER (New Scheme) SUBJECT CODE: MEL37 A YEAR: 2006 CLASS MARKS: 25

Sl.No

Expt. No. Title

No. of Class

Class & Test Marks

CYCLE I01 MT01 Tension Test on Mild Steel Specimen 01 2002 MT02 Torsion Test on Mild Steel Specimen 01 20

03MT03 Impact Tests (IZOD and CHARPY) on Mild Steel Specimen 01 20D01 Non-Destructive Tests Demonstration

04 MT04 Rockwell hardness Test 01 20CYCLE II

05 MT05 Wear Test 01 10

06MT06 Double Shear Test on Mild Steel Specimen

01 20D02 Fatigue Test demonstration

07 MT07 Compression Test on Mild Steel Specimen 01 2008 MT08 Brinell Hardness Test 01 20

CYCLE III09 MT09 Vickers hardness Test 01 1010 MT10 Bending Test on wood 01 20

11S01 Preparation of specimen for metallographic examination.

01 10S02 Microstructure study of the Engineering materials identification

12 D03 Heat treatment of steel materials & study of their hardness using their Rock-well testing machine--Demonstration 01 10

13 TEST 01 50TOTAL 13 250

KEY MT Materials Testing Expt. S Study Expt. D Demonstration Expt.


MATERIAL TESTING LAB


EVALUATION SCHEME:

CLASS MARKS = Class work total + Test Marks (Reduced to 25) 10

Proposed by: Prepared by: Approved byD.Venugopal setty.Shobha N S H.M.Shadakshara Prof.K.S.Badarinarayana

SYLLABUSMATERIALS TESTING LABORATORY

(Common to ME I IP I AU I IM I MA)Sub Code MEL37 A/MEL47 A IA Marks 25Hrs/Week 03 Exam Hours 03Total Hrs. 42 Exam Marks 50

PART-A

1. Preparation of specimen for metallographic examination of engineering materials and study the microstructure of plain carbon steel, tool steel, gray C.I, SG iron, Brass, Bronze.

2. Heat treatment: Annealing normalizing hardening and tempering of steel & to study their Rock-well hardness (Demonstration only)

PART-B

3. Conduction of tensile, shear, compression, torsion and bending tests of a Mild Steel specimen using a Universal Testing Machine.

4. Conduction of Izod and Charpy tests on Mild Steel Specimen.

5. Experiment on Wear Study.

6. Brinell, Rockwell and Vicker's Hardness tests.

7; .Fatigue Test- (demonstration only).

8. Non-destructive test experiments - (demonstration only).(a). Ultrasonic flaw detector(b). Magnetic crack detector(c). Dye penetrant testing

Scheme of Examination:ONE question from part -A : 10 Marks(Identification only)ONE question from part -B : 30 MarksViva-Voce : 10 Marks



INTRODUCTION:

Materials constitute an important component of the curriculum of every branch of engineering and applied science. For fabrication of machines, manufacture of parts, building of plants and structures, and carrying out processes, the choice of the material is critical. An awareness of materials available to the characteristic material properties & us are desirable for efficient problem solving, decision-making, and development of advanced materials and functioning of an engineer. The need for materials literacy of engineers and technologists is now recognized all over the world. It is clear that an engineer should keep the materials scenario in mind while designing a component or machine. Otherwise his design may become redundant. For the efficient design of engineering products, problem solving, decision making and the overall efficient functioning of an engineer, an awareness of available materials, there potentials and limitations, and an understanding of there properties and behaviour or desirable.

Every engineering material is known by its set of properties. A variety of tests are conducted in the Material Testing Laboratory to evaluate & compare the mechanical properties of different materials.

The Mechanical Properties are:

1. Stiffness2. Elastic Strength3. Yield Strength4. Ductility5. Malleability

6. Ultimate Tensile Strength7. Fracture Strength8. Stress9. Strain10. Toughness

These tests are classified into three categories:

1. Loading conditions Static tests - Tension, compression, Torsion, Bending, Shear Tests Dynamic testsImpact tests- Charpy Test, Izod Test Repeated loading - Fatigue test. High Temperature tests - Creep test

2. Hardness Tests Penetration Tests - Rockwell Hardness Test, Brinell Hardness Test, Vickers Hardness Test

3. Non- destructive Tests Visual Inspection Magnetic Particle inspection Magnetic crack detector Dye penetrate test

Radiography Ultrasonic test X-Ray test.



EXPERIMENT No. MT01

TENSION TEST ON DUCTILE MATERIAL

AIM: - To determine the strength and several properties of ductile steel, to observe the behaviour of the material under load and to study the fracture and thus determine the following:

1. Yield strength 2. Tensile strength

3. Ductility i. Percentage elongation ii. Percentage reduction in area4. Modulus of elasticity (Graphical Method)

APPARATUS / INSTRUMENTS / EQUIPMENT USED: -1. Universal Testing machine2. Extensometer3. Vernier caliper4. scale

UNIVERSAL TESTING MACHINE

Equipment Description:UTM as name implies, are general purpose machines. They vary greatly in physical size, load capacity, versatility & sophistication.

In its simplest form, a UTM system includes a load frame where the test is actually performed. The load frame must, of course, be rugged enough for the application. Some means of control over the load frame is necessary. This control can be as simple as hand wheel on a valve or as complex as a


l


computer to control the loading & unloading process and the rates at which these are done. Generally a recorder is used to record permanently the results of the tests.Grips or some other accessory are used to interphase between the sample being tested & the load frame itself. The action & use of the grips is often one of the most critical and least understood parts of the test.

Each UTM is desired to have a maximum load capacity. Small units may have a load of few 100N or even less.

The UTM can be used for:1. Tensile test2. Shearing test3. Compression test4. Bending test5. Functions of

i. Yield pointii. Elasticity Modulus,

iii. Young's Modulusiv. Ultimate valuev. Break value

PROCEDURE:-

1. Determine the average cross-section of the given specimen. Scribe a line along the bar and with a centre punch lightly mark a 120 mm gauge length symmetrical with the length of the bar.2. Firmly grip the upper end of the specimen in the fixed head of the testing machine using proper fixing devices or shackles. The specimen is placed such that the punch marks face the front of the machine 3. Firmly attach the extensometer to the specimen so that the axis coincides with that of the specimen. Adjust the testing machine and extensometer to read zero. Grip the lower end of the specimen taking care not to disturb the fixing of the extensometer.4. Select suitable increments of load (between 200 and 500 kgs) to obtain at least 15 readings of strain within the proportional limit. Apply the load at a slow speed, taking simultaneous observations of load and strain without stopping the machine. The extensometer is used only till the yield point value is reached at which point the extensometer dial makes two complete revolutions. After this, the elongation is observed on the scale fixed to the machine frame.5. Loading is continued till the failure of the specimen. Record the ultimate load and breaking load.

6. Remove the broken specimen from the machine and observe the failure characteristics. Measure the dimension of the smallest section. Hold the broken parts together and measure the gauge length.7. Plot a stress-strain diagram and mark the following on the graph:

a. Upper yield pointb. Lower yield point


l


c. Breaking stressd. Ultimate stress

8. Calculate the slope of the graph (within the elastic limit), which is the Youngs modulus value of the given material.

R.V. COLLEGE OF ENGINEERING, BANGALORE-560059DEPARTMENT OF INDUSTRIAL ENGG. AND MANAGEMENT

MATERIAL TESTING LABORATORY

OBSERVATION / DATA SHEET

Date: Name: USN:Lab : MT Lab Class: III Sem Expt.No:

Title of the Experiment: TENSION TEST

OBSERVATIONS:

Least count of extensometer =0.01mm Least count of Vernier caliper = 0.02mm

DETAILS OF SPECIMEN:

Material : Mild steelTotal length of specimen (L) :330mmLength between shoulders (l) :133mmGauge length (l1) :120mmDiameter at the ends (D) :19mmDiameter of reduced section (d) :14mmDiameter of ruptured section (d1) :8.5mmGauge length after fracture (l2) :15.5mm

SKETCH OF THE SPECIMEN:


d

l1

l

L

D

Shoulder


Contd..

Signature of the staff in charge





Title of the Experiment: TENSILE TEST

EXPERIMENTAL READINGS:

Sl. No

Load(Kg)

Extensometer Reading Scale reading (mm) RemarksLeft Right

1 500 3 02 1000 6 03 1500 7 14 2000 10 35 2500 11.5 4.56 3000 13 67 3500 15 88 4000 17 9.59 4500 19 1110 5000 20.5 1311 5500 22.5 16.5 Yield point12 6000 1.513 6500 314 7000 4.5



15 7500 6.516 8000 9.517 8500 13 Ultimate point18 8000 3519 6500 39.520 6000 40 Breaking point






Title of the Experiment: TENSILE TEST

Tabulated results: Sl.No

Load Extensometer Reading (mm)

Scale Reading

(mm)

Stress (N/mm2)

Strain Remarks

Left Right Average

1 4905 0.03 0 0.015 31.86 0.000132 9810 0.06 0 0.03 63.73 0.000253 14715 0.07 0.01 0.04 95.59 0.000334 19620 0.1 0.03 0.065 127.46 0.000545 24525 0.115 0.045 0.08 159.32 0.000676 29430 0.13 0.06 0.095 191.19 0.000797 34335 0.15 0.08 0.115 223.05 0.000968 39240 0.17 0.095 0.1325 254.92 0.001109 44145 0.19 0.11 0.15 286.78 0.0012510 49050 0.205 0.13 0.1675 318.65 0.0014011 53955 0.205 0.165 0.195 350.51 0.00163 Yield point

12 58860 1.5 382.38 0.012513 63765 3 414.25 0.02514 68670 4.5 446.11 0.037515 73575 6.5 477.97 0.054216 78480 9.5 509.85 0.07916



17 83385 13 541.70 0.1083 Ultimate point

18 78480 35 509.85 0.291619 73575 36 477.97 0.308320 68670 37.5 466.11 0.316721 63765 39.5 414.25 0.32922 58860 40 382.38 0.3334 Breaking

Point

Signature of the staff in charge Stress-Strain Diagram

0

100

200

300

400

500

600

0.000

13

0.000

33

0.000

67

0.000

96

0.001

25

0.001

630.0

25

0.054

2

0.108

3

0.308

30.3

29

strain

stre

ss(N

/mm

2)

SPECIMEN CALCULATION:

For Sl. No.3

1.Applied load , P = 1500 x 9.81 =14715 N

2.Area of cross section before fracture , A= pi d / 4 = pi x (14)2 /4 = 153.93 mm2

3.Area of cross section after fracture = pi d12 / 4 = pi x (8.5)2 /4 = 56.745 mm2

4.Applied stress = P / A = Load/ Initial area of cross section = 14715/153093 = 95.595 N/mm2 = 77.18 X106 N/m2



5. Strain = Change in length / Original length = 0.035/120= 0.000333

6. % Elongation = Change in gauge length X100 / Original gauge length = (L2 -L1 )X 100 / L1 = (155-120)X100/120 = 29.17%

7. % Reduction in area = (Original area Area after fracture)X100 / Original area = (153.93 56.745 )X100 / 153.93 = 63.135%

8.Yield strength = Load at yield point / Initial area of cross section = 5300*9.81/153.93 pi = 337.77 N/mm2 =3.377 X108 N/m2

9. Tensile strength = Maximum load / Initial area of cross section = 83385/153.93= 541.7 N/mm2 = 5.417 X108N/m2

10. Breaking strength = Load at break point / Initial area of cross section = 58860/153.93=382.382 N/mm2 =3.823 X108 N/m2

11.Modulus of elasticity (Graphical), E = Slope of Graph = 2.4 X1011N/m2

RESULT :-

Experimental results are as follows:

Percentage elongation = 29.166% Percentage reduction in area = 63.135%Yield strength = 3.377 X108 N/m2 Tensile strength = 5.417 X108N/m2 Breaking strength = 3.823 X108 N/m2 Modulus of elasticity (Graphical), E = 2.4 X1011N/m2



EXPERIMENT No. MT02

TORSION TEST

AIM: - To determine the behaviour of ductile steel when subjected to torsion, and obtain the following tensional properties:

Modulus of rigidity Maximum Shear strength of the material

APPARATUS/EQUIPMENT/INSTRUMENTS USED

Torsion testing machine, Torsion Shackles, Vernier Calipers

TORSION TESTING MACHINE

Equipment description: Torsion Testing Machine is designed for conducting Torsion and Twist on various metal wires, tubes, sheet materials.

This Machine applies a torque on the specimen held in its chuck and measures the twist.

Suitable for Torsion and Twist test on various metal rods and flats. Torque measured by pendulum dynamometer system.

Geared motor to apply torque to specimen through gear box. Set of jaws to accommodate different size and diameter of test specimens provided.







Title of the Experiment: TORSION TEST

OBSERVATIONS:

Least count of the Vernier caliper =0.01mm

Least count of the Torque Indicator r=60Kg-cm

Least count Twist Indicator =0.5

TORQUE AND TWIST READINGS:

Sl.No.TORQUE

Kg-Cm (x 60)Twist (Degrees)

1 21. 0 10 02. 3 20 0.253. 12 30 0.754. 14 40 1.005. 15 50 1.256. 16 60 1.257. 17 70 1.25




PROCEDURE:-

1. Measure the dimensions of the specimen using Vernier caliper 2. Fix the specimen between the shackles. The axis of the specimen should coincide with the

axis of the shackles 3. Rotate the wheel very slowly to give a twist of 1=104. Note down the corresponding torque developed (kg-cm), T and the angle of twist, 2 from the indicators.5. Increase the twist 1 in steps of 10 till the failure of the specimen. Note the corresponding values of 2 and T.6. Calculate the effective twist, = 1 ~ 2

7. Calculate shear strength using formula, = T x R / J8. Plot a graph between and . 9. Calculate rigidity modulus from the slope, G = Slope x L / R

TABULATION:

SlNo

Torque(division)

Torque(N-m)

TWIST (Degree)TWIST, (radians)

Shear Stress, (x108N/m2) 1

2

= 1 ~ 2

1 0 0 10 0 10.00 0.1745 02 3 17.658 20 0.025 19.75 0.3447 89.933 12 70.632 30 0.75 29.25 0.5105 359.724 14 82.404 40 1.00 39.00 0.6807 419.685 15 88.290 50 1.25 48.75 0.8508 449.666 16 94.176 60 1.25 58.75 1.0254 479.63


0

100

200

300

400

500

600

0.1745 0.3447 0.5105 0.6807 0.8508 1.0254

Twist (Radians)

Shea

r Str

ess

(x10

8 N/m

2 )


SPECIMEN CALCULATION (for sl.no.2)

1. Torque division = 3 Torque (T) = 3x60 Kg- CmT = 3x60x9.81/100 = 17.658 N m

2. Twist, = 1 ~ 2= 20 ~ 0.25 = 19.75 = 19.75 x pi /180 = 0.3447 radians 3. Diameter (D) = 10 mm,

Polar moment of inertia, J = pi D4 / 32 = pi (10)4 / 32 = 981.75 mm4 = 981.75 x10-12 m4

4. Shear stress, = T x R /J = 17.658 x (5/1000)/ 981.75 X10-12 = 8.993 x107 N/m2

5. Maximum shear stress, max = 5.0961 x108 N/m2

6. 1. Modulus of rigidity or Polar Moment of Inertia, G = Slope x L / R N/m2

=(1.56x103x130)/5=4.056x109 N/m2

RESULTS: -

1. Maximum shear stress = 5.0961 x108 N/m22. Modulus of rigidity = 4.056 x 109 N/m2



EXPERIMENT No. MT03IMPACT TEST IZOD AND CHARPY

AIM:- To determine the relative impact resistance of a given specimen by conducting the IZOD and Charpy tests.

APPARATUS / INSTRUMENTS / EQUIPMENT USED:-

Impact testing machine, Vernier caliper, Centerpiece or setting gauge, Allen key.

IMPACT- TESTING MACHINE

Theory: Impact loading differs from quasi-static loading. In that a load is applied over a very short time instead of being introduced gradually at some constant rate. This causes significant changes in the observed material properties from those associated with normal static tests. In the case of impact loading the effects measured are of a dynamic nature, with vibration and possibly fracture being observed.The Notched Bar test, where specimens are subjected to axial, bending or torsion loads using specialized testing machines. The technique involves swinging a weight of W from a certain specified height h to strike the notched specimen, breaking it as it passes through, and arriving at a



height h', lower than the initial position of the pendulum. The energy expended in rupturing the specimen can be described using the equation U = W (h-h')Where, W= Weight h & h= Specified height





Title of the Experiment: IMPACT TEST--- IZOD

OBSERVATIONS:

Least count of Vernier Calliper:0.02mmLeast count of the Dial on the Impact testing machine = 0.1 kg-m


Material Dimensions of the specimen

Notch angle

Dial Reading (Kg-m)

Initial (E1)

Final (E2)

Energy consumed(Kg-m)

Mild Steel

Length = 27.0mm.Diameter =12mmDia. of notch=9mmDepth of notch =1.5mmWidth of notch = 3.0mm

45 0 1.5 1.5

Cast Iron

Length = 25.0mmDiameter = 11.0mmDia .of notch = 7.84mmDepth of notch=1.58mmWidth of notch = 3.0mm

45 0 0.1 0.1



PROCEDURE: -

1. Raise the pendulum and fix it to the pendulum notch. Place a thick wooden plank on the stand below the pendulum pipe.

2. Keep the reading pointer at 17 kg-m on the inner scale. Release the Izod lever and allow the pendulum to swing freely. Arrest the movement of the pendulum by using the pendulum brake.

3. Record the indicator reading, which will give the energy lost due to friction and air drag. See if the pointer comes to o (Zero) reading. If not, there will be on error (in calibration of the instrument). Note that as initial reading. Again raise the pendulum and fix it onto the notch.

4. Measure the lateral dimension of the specimen at the full section and at the notch and check whether the dimensions conform to the given standard,

5. Now fix the Izod specimen inside the damping device, hold the specimen in hand vertically such that the half of the V-notch is just above the horizontal surface of the clamping device (cantilever beam position) and the notch is facing the pendulum.

6. Now insert the setting gauge such that the pointer edge of the setting gauge correctly fits inside the V-groove. Simultaneously tighten the clamping screw using allen key and check that there is no movement of the specimen.

7. After ascertaining that, there will be nobody in the range of swinging the pendulum.

8. Operate the Izod lever. Now the pendulum will swing freely and the specimen will be smashed. Care must be taken to see that proper range is selected on the indicator (The circular opening in the dial should be fully-3/4th red and partly black)

9. Stop the swinging pendulum by applying the pendulum brake.

10. Note the reading on the dial corresponding to the pointer.

11.Calculate the difference between final and initial readings. This value gives the impact energy consumed or lost in breaking the specimen.



TABULATION AND CALCULATION:-

Material Dial Reading Energy consumed

(E2- E1) (Kg-m)

EnergyConsumed(E2- E1) , JInitial E1

(Kg-m)Final E2(Kg-m)

Mild Steel 0 1.5 1.5 14.715

Cast Iron 0 0.1 0.1 0.981

SPECIMEN CALCULATION (For Mild Steel):-

Actual energy absorbed by the specimen during fracture= Energy recorded on the dial indicator with specimen in position - Energy recorded on the

dial indicator without specimen in position.

= 1.5- 0 = 1.5 Kg-m = 1.5x9.81 = 14.715 J

RESULTS:-

The actual energy absorbed by the specimens is as follows: -

1. Mild steel = 14.715 J2.Castiron = 0.981J







Title of the Experiment: IMPACT TEST---CHARPY

OBSERVATIONS:

Least count of Vernier Calliper:0.02mmLeast count of the Dial on the Impact testing machine =0.1Kgm


Material Dimensions of the specimenNotch angle

Dial Reading (Kg-m)

Initial (E1)

Final (E2)

Energy consumed

Brass Length = 60 mmBreadth = 10 mmWidth of the notch=10mmDepth of notch=02 mm

900 0 1.05 1.05

Mild Steel

Length = 56.20 mmBreadth = 9.76 mmWidth of the notch=10mmDepth of notch=02 mm

900 0 3.8 3.8




RESULT :

DIMENSIONS OF SPECIMEN BEFORE TESTING

SL.NO.

PARAMETERS MATERIALSBRASS MILD STEEL

1 Length of the specimen (mm) 56.20 55.202 Breadth of the specimen (mm) 9.76 9.723 Thickness of the specimen (mm) 9.72 9.64

SPECIMEN CALCULATION

BRASSActual energy absorbed by specimen during fracture

= Energy recorded on the dial indicator with specimen in position - Energy recorded on the dial indicator without specimen in position

= 1.05-0 = 1.05 kg-m = 1.05x9.81 = 10.30 N-m = 8.829 J

RESULTS: The actual energy absorbed by the different specimens are as follows:-Brass: - 10.3 JMild steal: -37.27 J



EXPERIMENT No. D01NON -DESTRUCTIVE TESTS

INTRODUCTION: -

A Non - destructive test is an examination of a component in any manner which will not impair its future use. Although non-destructive test do not provide a direct measurement of mechanical properties, but they are very useful in revealing defects in components which could impair their performance when put in service.

Non destructive tests make components more reliable, safe and economical.

ULTRASONIC TEST

AIM: To study the ultrasonic flaw detector and to determine the location of the interior crack or cavity in the given specimen.

APPARATUS: Ultrasonic flaw detector.

THEORY: Ultrasonic flaw detector is a device, which is used to detect internal discontinuities in the material by nondestructive means. It makes use of phenomenon of back reflection (echo) of waves by surfaces. When ultrasonic waves are made to pass through the test material, portion of the sound is immediately reflected from the surface at which they enter as a very large echo. Part of the sound will continue on into the test material, until it is partially reflected from the back surface as a second echo. If there is a discontinuity in the material, a portion of the sound will be reflected from the discontinuity and will return to the receiver as a separate echo between the echoes received from the front and back surface. The signals received are shown on a cathode ray tube, which also has a time base connected to it, so that the position of the signal on the screen gives an indication of the distance between the crystal generator and the surface from which the echo originates.

Sound waves oscillating with a frequency greater than 20,000 cps are inaudible and are known as ultrasound. High frequency sound is produced by a piezoelectric crystal, which is electrically pulsed and then vibrates at its own natural frequency. In order to transmit the sound waves from the crystal to the metal, it is necessary to provide a liquid couplant. This is accomplished by using a film of oil between the crystal and the test piece. After the crystal has given off its short burst of sound waves, it stops vibrating and listens for the returning echoes, i.e., one crystal probe is used to send and receive the sound. This cycle of transmitting and then receiving is repeated at an adjustable rate from 100 to 1000 times per second.

Returning echoes on the CRT causes short vertical spikes called pips. These are spaced along the baseline according to their time of receipt. Since the sound travels through the material at a constant speed, the spacing of the pips can be considered as indicating thickness. Selecting and expanding full screen size of the CRT can eliminate unwanted echoes caused by reverberations with the test piece.


U-Horse Magnet

Location of Crack

Magnetic particles


PROCEDURE:

1. Clean the surface of the test piece.2. Place the probe against the surface of test piece using thin oil film.3. Switch on the power supply of the ultrasonic wave generator.4. Adjust the number of cycles of transmitting and receiving the signals to the desired value.5. Select the segment of time, which contain the echo pips.6. Observe the echo from the cavity if any on the CRT and measure the relative distances of pips on the time axis.

Let A = Time elapsed between the pips of front surface echo and bottom surface echo (sec)

B = Time elapsed between the pips of front surface echo and cavity surface echo (sec)H = Thickness of test specimen (mm)

Location of the crack from the front surface x = (B/A)x h

ADVANTAGES:

1. It is a fast, reliable method of non destructive inspection2. It is a very sensitive method.3. The minimum flow size which can be detected is equal to about 0.1% of the distance from

the probe to the defect.4. Big castings can be systematically scanned for initial detection of major defects.5. Ultrasonic inspection involves low cost and high speed of operation.6. The sensitivity of ultrasonic flow detection is extremely high, being at a maximum when

using waves of highest frequency.

LIMITATIONS:

1. Ultrasonic inspection is sensitive to surface roughness since cost surfaces are usually rough, some preliminary machining an castings will be required.

2. In complex castings the interpretation of the oscillographic trace may not be easy. Waves reflected from corners or other surfaces may give a false indication of defects.

APPLICATIONS:

1. Inspection of large castings and forgings, for internal soundness, before carrying out expensive machining operations

2. Inspection of moving strip or plate (for laminations) as regards its thickness.3. Routine inspection of locomotive axles and wheel pins for fatigue cracks.4. Inspection of rails for bolt-hole breaks without dismantling railed assemblies.


U-Horse Magnet

Location of Crack

Magnetic particles


MAGNETIC PARTICLE TESTAIM: To detect the surface or subsurface crack of the given ferromagnetic material.

APPARATUS: Magnetic field generator and ferromagnetic powder.

THEORY: The magnetic particle method of inspection is a procedure used to determine the presence of defects at or near the surface of the ferromagnetic objects. This method consists of placing fine ferromagnetic particles on the surface. The particles can be applied either dry or in a liquid carrier such as water or kerosene. When the part is magnetized with a magnetic field, a discontinuity (defects) on the surface causes the particles to gather visibly around it. Thus, the defects become a magnet due to the principle of flux leakage where magnetic field lines are interrupted by the defect and collect the ferromagnetic particles. The collected particles generally take the shape and size of the defects. Sub surface defects can also be detected by this method, provided they are not deep. The ferromagnetic particles may be colored with pigments for better visibility on the metal surfaces.

The magnetic fields can be generated either with direct current or alternating current, using yokes, bars and coils. The equipment may be portable or stationery.Procedure:1. Clean the surface of the test specimen to remove scales, oil and grease.2. Apply a thin layer of ferromagnetic particles over the surface to be tested.3. Magnetize the test piece.4. Observe the shape and size of the magnetic particles collected, which is the shape and size of the defect.

VISUAL INSPECTION

Defects like surface cracks, tears, blowholes, metal penetration, rattails and buckles, swells, shifts, surface roughness and shrinkage are easily located by visual inspection.

It is carried out with the marked eye or using a magnifying glass. This method is the simplest, fastest and most commonly employed, but requires greater skill on the part of the inspector to locate and identify different manufacturing defects.

The inspector identifies the casting defects and assigns their cause to some foundry operation or raw materials so that corrective measures can be employed.

Visual inspection ensures that none of the features of a casting has been omitted or malformed by moulding errors short running or mistakes in fitting.


U-Horse Magnet

Location of Crack

Magnetic particles


LIQUID PENETRANT TEST

AIM: To detect the surface defects by penetrant test.

APPARATUS: Penetrant, developer and ultraviolet light source.

THEORY: In the liquid penetrant test, liquids are applied to the surface of the part and allowed to penetrate into surface openings, cracks, seams and porosity. Two commonly known types of liquid penetrants are: (a) Fluorescent Penetrants which fluoresce under ultraviolet light, and (b) Visible penetrant using dyes, usually red if which appear as bright outlines on the surface.The test piece is coated or socked in a liquid penetrant and the surplus coating is wiped off. After a short time, a developing agent is added to allow the penetrant to seep back to the surface (due to capillary action) and spread to the edges of openings. The surface is then inspected for defects, either visually in the case of dye-penetrants or under ultraviolet light for fluorescent penetrant. The developer includes dry powders, aqueous liquid and non-aqueous liquid. This method is capable of detecting variety of surface defects and is used extensively.

PROCEDURE:1. Clean the test piece surface to remove scales, oil and grease.2. Immerse the test piece in the selected penetrant and hold it for some time.3. Remove the excess penetrant on the test piece surface.4. Apply the developer on the surface of the test piece.5. Examine the surface of the test piece under appropriate viewing conditions.6. Clean the surface to prevent corrosion, etc.

OTHER NON-DESTRUCTIVE TESTS

1. Hammer Test2. Radiography Test

X- Ray radiographyGamma-ray radiography

3. Testing for metal composition -Wet analysis

- Spectroscopy - Spot test techniques.

EXPERIMENT No. MT04

ROCKWELL HARDNESS TEST



AIM:- To determine the Rockwell hardness number of the given specimen.

APPARATUS / INSTRUMENTS / EQUIPMENT USED:-

Rockwell Hardness tester Indentors

ROCKWELL HARDNESS TESTER

Equipment Description: Rockwell HTM impacts a standard load on a steel ball or diamond indenter.

Rockwell hardness test determines the hardness of ceramic substrates. The most common method of calculating hardness of plastics such as nylon, polycarbonate, polystyrene, and acetal is done by Rockwell hardness test. This test is also used for measuring the resistance of the plastic to indentation. The dial gauge is used to calculate the difference in depth produced by two different forces. The load applied, indenter diameter and the indentation depth can be measured using Rockwell hardness value.







Title of the Experiment: ROCKWELL HARDNESS TEST

OBSERVATIONS AND TABULATION

SL.NO Material Scale Load(Kg) IndenterRockwell Hardness NumberTrail 1 Trail 2 Trail 3

1 Mild steel C 150 Cone(120) 107 107 1082 Cast Iron C 150 Cone(120) 93 94 933 Brass B 100 Ball (1/16th 48 51 464 Copper B 100 Ball (1/16th 91 95 1015 Aluminium B 100 Ball (1/16th 52 54 52




SELECTION OF LOAD AND INDENTOR

PROCEDURE

1. Place the specimen on the anvil.2. Select the load and indentor combination based on specimen material.3. Raise the anvil until the specimen comes in contact with the indentor. Continue to raise the

anvil slowly till the pilot lamp goes off. This indicates that the minor load of 10 kg is acting on the indentor.

4. Actuate the lever to apply the major load.5. Give at least 10 seconds after the lever comes to rest position.6. Read the position of the pointer on the corresponding scale of the dial, which gives the

Rockwell hardness number.7. Make three tests on each specimen.8. Calculate average Rockwell hardness number.9. Plot the bar chart separately for B-Scale and C-Scale


ScaleSymbol

Major Load (Kg)

Indentor Application

A 60 Cone Cemented carbide, thin steel, hardened steel.

B 100 (1/16) Ball Copper alloys, Soft Steels, Aluminum Alloys, Malleable Iron

C 150 Cone Steel, Hard cast Iron, Paralyte malleable Iron, Deep case hardened steel.


TABULATION AND CALCULATIONS:-

SL. NO Material Scale Load(Kg) Indenter

Rockwell Hardness NumberTrial

1 Trial 2 Trial 3 Avg.RHN

1 Mild steel C 150 Cone(120) 107 107 108 107.332 Cast Iron C 150 Cone(120) 93 94 93 93.33

3 Brass B 100Ball dia

(1/16th of an inch)

48 51 46 48.33

4 Copper B 100Ball dia (1/16th

of an inch)

91 95101 95.66

5 Aluminium B 100Ball

dia(1/16thof an inch)

52 5452 52.66

SPECIMEN CALCULATION:-

Material : BRASS

Scale : B-Scale

Indentor = 1/16 Ball Indentor

Major Load Applied = 100 Kgs

Rockwell Number for trail 1, RHN1 = 48

Rockwell Number for trail 2, RHN2 = 51 Rockwell Number for trail 3, RHN3 = 46

Average Rockwell Number = (RHN1+RHN2+ RHN3) / 3 = (48+51+46) / 3 = 48.33 Kg/cm2

RESULTS:-

MATERIAL ROCKWELL HARDNESS NUMBER

Cast Iron 93.33Mild Steel 107.33

Brass 48.33



Copper 95.66Aluminium 52.66

C Scale

93.33

107.33

85

90

95

100

105

110

Cast Iron Mild Steel

Materials

Rock

wel

l Har

dnes

s No

.

B Scale

48.33

95.66

52.66

0

20

40

60

80

100

120

Brass Copper Aluminium

Materials

Roc

kwel

l Har

dnes

s N

o.



EXPERIMENT No. MT06

DOUBLE SHEAR TEST

AIM:- To conduct a Double shear test on different materials and obtain their shear strengths.

APPARATUS / EQUIPMENT / INSTRUMENTS USED:-

Universal testing machine, Vernier calipers, Double shear shackles.

UNIVERSAL TESTING MACHINE

DOUBLE SHEAR SHACKLES AND SPECIMEN:







Title of the Experiment: DOUBLE SHEAR TEST

OBSERVATIONS:

Least count of vernier caliper =0.02mm

TABULATION

Sl. No. MATERIAL DIAMETER (mm) Failure Load (Kg)

1 Brass 7.7 32002 Mild Steel 7.7 4300




PRINCIPLE:

Shear stress is caused by forces which act parallel to in area if cross-section and tend to produce sliding of one portion past another portion as shown in figure below:

If the force is resisted by failure through one plane and single area, then the material is said to be in single shear. In single shear,

= 222 /4

4section cross of areaload failure mN

DP

DP

AP

pipi===

Where, D - initial diameter of the specimen.

P - failure load.

If 2 areas resist the fracture, then the area is said to be in double shear.

22 /

22section cross of Area2

Load Failure mNDP

AP

pi ==

=

For conduction shear test, a suitable steel shackle may be fabricated based upon fork and eye plate principle the specimen is inserted as a connecting pin in the bush housing between the shackles; the fork plates of the shackle held rigidly together by bolts for avoiding any bending tendency of the specimen under high loads, and is tested in double shear.

1. The diameter of the specimen is measured using vernier calipers and the area of cross section of the specimen is calculated.

2. The specimen is than inserted inside the shear shackles & is placed inside the shear center plate.

3. The entire assembly is then placed on the lower cross slide of the universal testing machine.


P

P P


4. The intermediate cross slide is then moved down till it makes contact with the top of the centre plate, through which the load is applied on the specimen.

5. The machine is started and the load is applied gradually till the specimen fails. At this point note down the load and the corresponding dial gauge reading.

OBSERVATION:Sl. No. MATERIAL DIAMETER (mm) Failure Load (Kg)

1 Brass 7.7 32002 Mild Steel 7.7 4300

CALCULATION OF DOUBLE SHEAR STRENGTH

MILD STEEL

Area of cross section, ( )

26-

222

1046.566

566.4647.7

4m

mmdA

=

=== pipi

Double strength,

( ) 266 /10937.45210566.46281.94300

section cross of Area2Load Failure mN=

=

=

BRASS

Area of cross section, ( )

26-

222

1046.566

566.4647.7

4m

mmdA

=

=== pipi

Double strength,

( ) 266 /10069.33710566.46281.93200

section cross of Area2Load Failure mN=

=

=

RESULT:

SL.N0 MATERIAL DOUBLE SHEAR STRENGTH

1 MILD STEEL 452.937 X106 N/m2 2 BRASS 337.0699 X106 N/m2

EXPERIMENT No. D02



FATIGUE TESTAIM: To determine the fatigue limit and the fatigue strength.

APPARATUS: Fatigue testing machine and micrometer caliper.

THEORY: Failure due to repeatedly applied load is known as fatigue. The physical effect of a repeated load on a material is different from the static load, failure always being brittle fracture regardless of whether the material is brittle or ductile. Mostly fatigue failure occurs at stress well below the static strength of the material. If the applied load changes from any magnitude in one direction to the same magnitude in the opposite direction, the loading is termed completely reversed, where as if the load changes from one magnitude to another (the direction does not necessarily change), the load is said to be fluctuating load.Fatigue testing machine: In the simplest type of machine for fatigue testing, the load applied is of bending type. The test specimen may be of simply supported beam or a cantilever. R.R.Moore rotating beam type machine for a simply supported beam.A specimen of circular cross-section is held at its ends in special holders and loaded through two bearings equidistant from the center of the span. Equal loads on these bearings are applied by means of weights that produce a uniform bending moment in the specimen between the loaded bearings. A motor rotates the specimen. Since the upper fibers of the rotating beam are always in compression while the lower fibers are in tension, it is apparent that a complete cycle of reversed stress in all fibers of the beam is produced during each revolution. A revolution counter is used to find the number of cycles the specimen is repeatedly subjected to the load. For simply supported beam, maximum bending moment is at the center.The testing techniques are subjected to a series of identical specimens to loads of different magnitudes and note the number of cycles N of stress (or load) necessary to fracture the specimen. The data are plotted on a semi logarithmic paper, the stress S being plotted to a linear scale and the number of cycles N to a logarithmic scale.This is known as stress-cycle (S-N) diagram and the fatigue limit can be, determined from the diagram. Fatigue limit or endurance limit is the stress below, which a material can be, stressed cyclically an indefinitely large number of times without failure. The fatigue strength is the stress at which a metal fails by fatigue after a certain number of cycles.Specimens: All specimens should be taken from the same rod, each specimen should receive same kind of machining and heat treatment. The specimens for tests have no sharp stress raisers. The surface of the specimen is polished.

Fracture appearance: Under repeated loading, a small crack forms in a region of high-localized stress, and a very high stress concentration accompanies the crack. As the load fluctuates, the crack opens and closes and progresses across the section. Frequently this crack propagation continues until there is in sufficient cross section left to carry the load and the member ruptures, the failure being fatigue failure. Therefore fractured surface shows two surfaces of distinctly different appearance.

1. A smooth surface where the crack has spread slowly and the walls of the crack are polished



by repeated opening and closing. This surface usually shows characteristic of beach or clamshell marking.2. A crystalline or fibrous surface where sudden failure occurred.

PROCEDURE: 1. Measure the diameter d and the length L of the specimen. 2. Fasten the specimen in the chucks of the testing machine. 3. Set the maximum load. Set the counter to zero, and start the machine. 4. Note the number of cycles N the specimen experiences before fracture. 5. Repeat the above test on the other specimens with gradually reduced loads. Draw the S-N diagram and obtain the endurance limit.



EXPERIMENT No. MT10

BENDING TEST

AIM:- To conduct the bending test on the given material and there by determine the following:

i. Stiffness ii. Maximum bending moment iii. Maximum bending stress at failure iv. Modulus of elasticity


Universal Testing Machine Cathetometer Bending test attachment Former (acting as a knife edge to apply a concentrated load at the center of the specimen)

Cathetometer

The Cathetometer can measure with great precision the difference in level between two points whether or not they lie on the same vertical line. This instrument is made of a robust graduated vertical copper rod, more than a meter long. The rod turns on its axis and is mounted on a tripod with leveling screws. Attached to the rod are two horizontal collimeter telescopes attached to tracks which have a ruler and a pointer and which can slide along the rod. The instrument's case has the form of a right angle prism and rests on a strong metallic tripod. Less sophisticated cathetometers have one telescope with which the two points are collimated successively.



If two points, A and B, are collimated through the telescopes and the positions assumed by the two pointers are read on the scale, the difference between gives the distance between the horizontal planes of the two points. The collimation is effected by creating a coincidence between the image of the point (observable through the telescopes) and the center of the instrument's optical grid. The degree of precision obtained in measurement depends on the approximation obtained with the ruler and on the care with which the graduated rod is put vertical and the telescopes horizontal.







Title of the Experiment: BENDING TEST

OBSERVATIONS Least count of vernier caliper = 0.02mm

Least of cathetometer = 0.01mm

MATERIAL SPECIFICATIONS

Length (l) mm 400Breadth (b) mm 46Thickness (d) mm 71

LOAD AND DEFLECTION READINGS

Cathetometer initial reading = 17.272mmSl. No Load (Kg) MATERIAL: MATTI WOOD

Final Reading Final-Initial Reading1 0 17.272 02 300 17.403 0.1313 600 17.413 0.1414 900 17.413 0.1415 1200 17.541 0.2696 1500 17.788 0.5167 1800 18.007 0.7358 2100 18.126 0.8549 2400 Breaking point


PRINCIPLE



A bending test can be performed on an actual being cross -section by using a 3-point loading system. The bending fixture is supported on the platform of the hydraulic cylinder of the UTM , The loading edge is held in the middle or intermediate crosshead. At a particular load , the deflection at the centre of the beam is determined using a dial gauge.

The deflection at the centre of the beam is given by = W L 3 / (48 E I )

E = W L 3 / (48 I ) Stiffness , W/ = 48 EI/ L3This is derived from the bending equation , M/I = / y = E/R

The beam with simply supported at two ends and loaded at the centre is as shown in figure

For the above beam

Maximum bending moment = WL/4 Since cross section of beam is rectangle with dimensions b&d,I = bd3 / 12 Therefore, s = 3WL / (2d3) N/m2

Where L = Length of the specimen in meters, b = breadth of the specimen in meters ,

d = depth or thickness of the specimen in meters , W= Applied load in N


W

W/2W/2L/2 L/2


PROCEDURE

1. The bending test attachment is fitted in the universal testing machine and the specimen is fixed in it using the special shackles provided for the purpose.

2. The breadth and thickness of the specimen are measured using vernier caliper and its length determined after fixing

3. The loading former is fixed in the intermediate cross head firmly and is adjusted till it just touches the specimen.

4. Record the initial cathetometer reading .5. Load is applied, and after every 300 Kg, the cathetometer is focused on the wood specimen

and the corresponding reading recorded. 6. Loading is continued till the specimen fails7. Calculations are made.8. A graph of load against deflection is plotted.

Principal features of supporting and loading devices for BEAM TESTS indicating provision for longitudinal and lateral rotational adjustment at support

DEFLECTION MEASURING DEVICES



BENDING OF A BEAM

MATERIAL: TEAK WOODBENDING MOMENT CALCULATIONS

SL. NO.

LOAD W (X9.81 N)

DEFLECTION READING (mm) Bending moment (N-m)

1 0 162.60 162.60 0 02 300 162.60 163.53 0.93 286.943 600 162.60 164.03 1.43 573.894 900 162.60 164.42 1.92 860.835 1200 162.60 165.16 2.56 1147.776 1500 162.60 165.34 2.74 1434.717 1800 162.60 165.50 2.90 1721.668 2100 162.60 166.00 3.40 2008.609 2400 162.60 166.64 4.04 2295.5410 2700 162.60 166.80 4.20 2582.4811 3000 162.60 167.32 4.72 2869.43

MATERIAL : MATTI WOOD

BENDING MOMENT CALCULATIONS

LOAD W (X9.81 N)

DEFLECTION (mm)Bending moment

(N-m)INITIAL FINAL = Final Initial 1 0 17.272 17.272 0 02 300 17.272 17.403 0.131 286.943 600 17.272 17.413 0.141 573.89



4 900 17.272 17.413 0.141 860.835 1200 17.272 17.541 0.269 1147.776 1500 17.272 17.788 0.516 1434.717 1800 17.272 18.007 0.735 1721.668 2100 17.272 18.126 0.854 2008.609 2400 17.272 Breaking

point




DEFELECTION vs LOAD GRAPH FOR TEAK WOOD

0

500

1000

1500

2000

2500

3000

3500

0 0.93 1.43 1.92 2.56 2.74 2.9 3.4 4.04 4.2 4.72DEFLECTION (X0.001 m)

LOAD

(X9.

81 N

)

DEFLECTION vs LOAD FOR MATTI WOOD

0200400600800

1000120014001600

0 1.15 1.65 2.25 1.05 3.35

DEFLECTION (X0.001 m)

LOAD

(X9.

81 N

)



MATERIAL : TEAK WOOD (Sl. No. 2)

1. Deflection, = Final reading - Initial reading = (17.541-17.272) = 0.269 mm =26.9 x 10-3 m

2. Load, W = 1200 Kg = 1200 x 9.81= 11772 NLength of the specimen, l = 400.0 mm = 0.4 mBreadth of the specimen, b =47.0 mm = 0.47mThickness of the specimen, d = 71.0 mm = 0.071m

3. Bending moment, M = W l / 4 = 11772x 0.4 /4 = 1177.2 N-m 4 Maximum bending moment = Wmax x l /4 = 3000 x9.81 x 0.39/4 = 2869.43N-m5 Momentum of inertia, I = bd3/12= 0.47 x (0.71 )3/12 = 1.4018 x 10-6 m4

6 Stiffness = W / = 2400 x 9.81/ 26.9 x 10 3 N/m = 875.24 x 103 N/m

7 Maximum bending stress = 3 Wmax L/ ( 2 bd2 )

= 3 x 3000 x 9.81 x 0.4 / (2 x 0.071 x (0.047)2) = 91.82 x 106 N/m2 8 From graph W vs ,

W = 2500x9.81 N = 3.9 x 10-3 m Now,

Youngs Modulus, E = WL3 / (48 I ) = 4.28 x 1015 N/m2

RESULT :

SL. No

PROPERTIES MATERIALS

TEAK WOOD MATTI WOOD

1 Modulus of Elasticity 9.95 x 109 6.19 x 1092 (Youngs Modulus) ( N/m2) 2869.43 1397.933 Maximum Bending (N-m) 6.29 x 106 4.04 x 1064 Stiffness (N/M) 91.82 x 106 44.17x106

CONCLUSION:

From above results, it can be concluded that Teak Wood is having more strength than Matti Wood



EXPERIMENT No. MT08

BRINELL HARDNESS TEST

AIM:- To find out the Brinell Hardness Number for the given specimen/s of ferrous metals (mild steel, cost iron) and non-ferrous metals (copper, Brass)

APPARATUS / EQUIPMENT/INSTRUMENTS USED:-

Brinell hardness testing machine , Ball Indentor Traveling microscope .

Brinell Hardness Testing Machine

Equipment Description:Brinell HTM measures the resistance of a material to the penetration of a hardened steel ball subjected to a standard load.

This Hardness Tester uses a machine to measure hardness by determining the depth of penetration of a spherical shaped device under controlled conditions. A carbide sphere of a specified diameter under a specified load is applied to the surface of the material and the diameter of the indentation is measured. The diameter of the indentation made is measured with the aid of Microscope.

The Brinell hardness value is obtained by dividing the load to the actual surface area. This number is used to make relative comparisons of the different materials.The formula used to calculate the Brinell hardness number is as follows:



Brinell Hardness Number (BHN) = F/[/2 (D-D- Di)]WhereF - Applied LoadD - Diameter of the spherical indenterDi -Diameter of the resulting indenter impression

These machines are robustly built to provide laboratory accuracy in the harshest industrial environments and are used all over the world. The only disadvantage is more time is consumed for measuring hardness.







Title of the Experiment: BRINELL HARDNESS TEST

OBSERVATIONS:

Diameter of ball indenter =2.5mm

Least count of micrometer =0.001mm

TABULATION:

Sl.

No.MATERIAL

LOAD

(KG)

Duration of

loading (sec)

Diameter of

indentation(mm)1 Steel 187.5 15 1.117 1.255 1.2472 Cast Iron 187.5 15 1.043 1.031 1.0453 Brass 62.5 15 0.82 0.812 0.8314 Copper 62.5 15 0.965 0.955 0.975


DERIVATION FOR BRINELL HARDNESS NUMBER

The principle of the Brinell Hardness Number is as shown in Figure . From the geometry of the figure,



h = depth of indentation in mm d = diameter of indentation in mm D = diameter of indentor ball in mm

From triangle OAE, OA =Sqrt ( OE2 EA2) = Sqrt[( D/2)2 (d/2)2] h = OB- OA = D/2 - Sqrt[( D/2)2 (d/2)2] Area of spherical indentation,

A = P x DXh=P x Dx{D/2 - Sqrt[( D/2)2 (d/2)2]} = P x (D/2) x{ D - Sqrt[( D)2 (d)2]}

BHN = Load / Area of spherical indentation = P

P x (D/2) x[( D Sqrt [( D)2 (d)2]

Cross Sections of Indentation in Brinell Test

PROCEDURE:

1. Place the polished specimen on the platform.

2. Raise the platform till the surface of the specimen gets focused on the microscope screen.


h

D/2 D/2O

d

C EA

Bh


3. Select the load by pressing the load selector.Load P : 30XD2 for ferrous materials

:10 D2 For non ferrous materials : 5 D2 for soft metals and alloys

Where P is the load in kg. and D is the diameter of the indentor in mm.

4 Press the actuator in position,then the load acts on the indentor.5. Wait till the handle on the left side of the frame comes to rest position. Now allow the load to

act for 15 seconds for ferrous materials and 30 seconds for non ferrous materials.6. Press the handle down without jerk to release the load and to bring the objective lens back into

position7. Measure the diameter of the indentation using the micrometer and microscope8. For each materials make at least three indentations and measure the diameters.

9. Calculate the BHN for each diameter obtained and take the average of the three.10. Tabulate the results.11. Draw the Bar chart

TABULATION AND CALCULATIONS

Sl No

Material Load (Kg)

Duration Of Loading

(Sec)

Diameter of Indentation (mm)

Average BHN

(X108N/M2)1 COPPER 62.5 30 0.965 0.955 0.975 8.052 BRASS 62.5 30 0.82 0.812 0.831 11.4783 MILD STEEL 187.5 15 1.117 1.255 1.247 15.3944 CAST IRON 187.5 15 1.043 1.031 1.045 21.112




MATERIAL : COPPER

Applied Load, P = 62.5 Kg.

Diameter of Ball, D = 2.5 mm

Avg.Diameter of Indentation, d= 0.965 mm

BHN = P / [ pi x (D/2) x (D- Sqrt D2 d2)] = 62.5 / [pi x(2.5/2)x(2.5 Sqrt (2.5)2 (0.965)2)] = 82.143Kg / mm2 = 82.143x9.81 N /mm2 = 8.05 x 108 N/m2

RESULT:

1. Bar chart was drawn for the given materials

2. The BHNs of the given materials are as shown in below:

SL. NO

MATERIAL BRINELL HARDNESS NUMBER

(X108N/ m2)1 COPPER 8.05 2 BRASS 11.4783 MILD STEEL 15.3944 CAST IRON 21.112

8.0511.478

15.394

21.112

0

5

10

15

20

25

COPPER BRASS MILDSTEEL

CAST IRON

Materials

Brin

ell H

ardn

ess

Num

ber



EXPERIMENT No. MT09

VICKERS HARDNESS TEST

AIM: - To determine the Vickers Hardness number of the given material

APPARATUS/EQUIPMENT/INSTRUMENTS USED: - Vickers Hardness Tester, Diamond pyramid indentor.

Vickers Hardness Testing Machine

Vickers HTM is used to measure hardness of metals with hard surfaces. It is measured from the size of an impression produced under standard load by a diamond indenter used, which is pyramid-shaped. The diagonal length is measured with a Microscope. The formula used to calculate the Vickers Hardness Number is as follows:Vicker Number (HV) = 1.854(F/ D)

Where,F - Applied Load, D - Indentation Area

Advantages of Vickers Hardness Tester The diagonal of the square can be measured easily and accurately Easier method for testing harder materials.

Disadvantages of Vickers Hardness Tester More Complicated & Expensive







Title of the Experiment: VICKERS HARDNESS TEST

OBSERVATIONS:

Indentor = Square pyramid indentor Least count of traveling micrometer =0.001mm

TABULATIONS

Sl. No. MATERIAL Standard Load P

(Kg)

Diagonal width (mm)

d1 d21 BRASS 20 0.500 0.500 0.486 0.500 0.467 0.5002 CAST IRON 30 0.501 0.530 0.544 0.559 0.516 0.5393 MILD STEEL 30 0.618 0.610 0.625 0.618 0.620 0.6134 COPPER 20 0.569 0.553 0.558 0.547 0.547 0.5481 BRASS 20 0.500 0.500 0.486 0.500 0.467 0.500




THEORY :-

Vickers hardness number indicate the extent of resistance offered by the material to permanent indentation under static loading .

The test consists in forcing a square based diamond pyramid (with an angle of 1360 between opposite faces) into the ground or polished surface to be tested. The pyramidal indentor makes impressions that remain geometrically similar irrespective of its size.

The hardness number is derived from the relationship between the applied load and the surface area of the indentation.

Definition: Vickers hardness number is defined as the ratio between load and surface area of the impression and is calculated by formula,Vickers hardness number (VHN) = 2 P sin (q/2)/ d2 = (1.854xP/d2) Kg/mm2

=(18.188 x 106 x P/d2) /m2

Where P = applied load in kg d = Length of diagonal of indentation in m = apex angle of the pyramidal indentor

PRINCIPLE :-

Diamond pyramid Indentor(included angle 1360 )

Top view of indentation


d1

d2


PROCEDURE:-

1. Place the polished specimen on the platform

2. Raise the platform till the surface of the specimen is focused on the microscope screen.

3. Select the load by pressing the load selector button

4. Load , P = 30 Kg, For ferrous materials

5. = 20 Kg. For non-ferrous materials

6. Wait till the handle on the left side of the frame comes to rest position, and after that

allow the load to act for 15 seconds for ferrous materials and 30 seconds for non-ferrous

materials

7. Press the handle down without any jerk to release the load and to bring the objective lens back into the position

8. Measure the length of the diagonals (d1 and d2) using the traveling micrometer and calculate their average, d.

9. For each material make at least three indentations and measure the length of the diagonals 10.Using the formula, calculate the Vickers hardness number for each trial and calculate their

average.

TABULATION AND CALCULATIONSSl. No.

MATERIAL Load (Kg)

Length of diagonal (mm) VHN X106 N/m2

Average VHNX106

N/m2d1 d2 d=(d1+d2) / 2

1 BRASS 20 0.5000.5000.486

0.5000.4760.500

0.5000.4880.493

1455.021527.461496.65

1493.04

2 COPPER 20 0.5690.5530.558

0.5470.5470.548

0.5580.5500.553

1168.261202.491189.48

1186.74

3 CAST IRON 30 0.5410.5300.544

0.5590.5160.539

0.5500.5230.542

1803.741994.791857.38

1885.3

4 MILD STEEL 30 0.6180.6100.625

0.6180.6200.613

0.6180.6150.619

1428.641442.611424.03

1431.76




Material : Brass

Load,P = 20 Kg = 20 x 9.81 N = 196. 2 N

For Trial 1, Length of diagonals, d1 = 0.500 mm & d2 = 0.500 mm Average length of diagonal, d = (d1 +d2)/2 = (0.500 +0.500)/2

= 0.500 mm = 0.500 x 10- 3 m VHN1 = (18.188 x 20)/ (0.500 x 10- 3 ) 2 = 1455.02 x 106 N/m2

VHN2 = (18.188 x 20)/ (0.488 x 10- 3 ) 2 = 1527.46 x 106 N/m2

VHN3 = (18.188 x 20)/ (0.493 x 10- 3 ) 2 = 1496.65 x 106 N/m2

Average VHN = (VHN1+VHN2+VHN3) / 3

= {(1496.63+1455.02 +1455.02) x 106} / 3 N/m2 = 1493.04 x 106 N/m2

RESULTS:-

MATERIAL VICKERS HARNESS NUMBER (x106 N/M2)

COPPER 1186.74BRASS 1493.04CAST IRON 1885.30MILD STEEL 1431.76

1186.74

1493.04 1431.76

1885.3

0200400600800

100012001400160018002000

COPPER BRASS CAST IRON MILD STEEL

Materials

Vick

ers

Har

dnes

s N

o.

EXPERIMENT No. MT07



COMPRESSION TEST

AIM: To study the behaviour of the given materials under compressive loading and to determine the following properties:

1. Maximum Compressive strength,2. Proportional limit,3. Elastic limit (Youngs modulus)


Universal testing machine, Vernier Caliper, Compression shackles.

Universal Testing Machine







Title of the Experiment: COMPRESSION TEST

OBSERVATIONS:

Least count of Vernier Caliper =0.02mm

TABULATION

SL.

NO.

CHARACTERISTIC OF THE

SPECIMEN

MATERIAL

BRASS MILD STEEL

1

. Initial Height of the specimen (hi) mm

22.00 21.16

2

. Initial Diameter of the specimen (di) mm

18.00 18.40

3

. Final Height of the specimen (hf) mm

16.78 14.70

4

.

Final Diameter of the specimen (df) mm 21.60 22.60




TABULATION:

INITIAL SCALE READING = 100 mm

MATERIAL : MILD STEEL MATERIAL : BRASSSL. NO

LOAD (KG)

SCALE READING (mm)

SL. NO LOAD (KG) SCALE READING

(mm)1 0 100 1. 0 10.02 1000 101 2. 1000 10.03 2000 101 3. 2000 10.04 3000 101 4. 3000 10.05 4000 101 5. 4000 10.06 5000 101 6. 5000 10.07 6000 101 7. 6000 10.08 7000 101 8. 7000 10.09 8000 101 9. 8000 10010 9000 101 10. 9000 10111 14000 102 11. 10000 10112 15000 103 12. 11000 10113 16000 104 13. 12000 10114 17000 104 14. 13000 10115 18000 105 15. 14000 10116 19000 105 16. 15000 10217 20000 106 17. 16000 10318 21000 106 18. 17000 10319 22000 106 19. 18000 10320 23000 106 20. 19000 10421 24000 107 21. 20000 10422 25000 108 22. 21000 10423 14000 102 23. 22000 10424 15000 103 24. 23000 105

25. 24000 10526. 25000 105



27. 26000 10628. 27000 10629. 28000 106

PROCEDURE :

1. Fix the lower and upper compression plates in between the bottom cross head and intermediate crosshead.

2. Measure the initial diameter (di) and initial height (hi) of the given specimen using vernier caliper.

3. Place the specimen at the centre of the bottom plate and bring the top of the specimen in contact with the top plate by moving the intermediate cross head down wards.

4. Apply compressive load in steps of 1000 Kg.5. The experiment is continued till the specimen attains a barrel shape on reaching the max load

for ductile materials or fractures at maximum load for brittle materials.6. 6.Record load values and corresponding decrease in heights form the scale which is fixed to

the UTM.7. Measure final height (hf ) and largest diameter of the specimen (df) using vernier caliper8. Calculate stress and corresponding strain.9. Plot the stress- strain diagram .

10. Calculate the youngs modulus from the graph ( Slope of the graph with in elastic limits)

MATERIAL : BRASS

INITIAL SCALE READING = 100 mm , A= 254.47mm2

SL NO LOAD(Kg)

SCALE READING

(mm)

STRESS x106(N/m2)

STRAIN

1 0 100 0 02 1000 100 38.55 03 2000 100 77.10 04 3000 100 115.65 05 4000 100 154.20 06 5000 100 192.75 07 6000 100 231.30 08 7000 100 269.85 0



9 8000 100 308.41 010 9000 101 346.96 0.04511 10000 101 385.51 0.04512 11000 101 424.06 0.04513 12000 101 462.61 0.04514 13000 101 501.16 0.04515 14000 101 539.71 0.04516 15000 102 578.26 0.09117 16000 103 616.81 0.13618 17000 103 655.36 0.13619 18000 103 693.91 0.13620 19000 104 732.46 0.18221 20000 104 771.01 0.18222 21000 104 809.56 0.18223 22000 104 848.12 0.18224 23000 105 886.67 0.22725 24000 105 925.22 0.22726 25000 105 963.77 0.22727 26000 106 1002.32 0.27328 27000 106 1040.87 0.27329 28000 106 1079.42 0.273

MATERIAL: MILD STEELINITIAL SCALE READING :-

SL NO LOAD(Kg)

SCALE READING

(mm)

STRESS x106(N/m2)

STRAIN

1 0 100 0 02 1000 100 38.55 03 2000 100 77.10 04 3000 100 115.65 05 4000 100 154.20 06 5000 100 192.75 07 6000 100 231.30 08 7000 100 269.85 09 8000 100 308.41 010 9000 101 346.96 0.04511 10000 101 385.51 0.04512 11000 101 424.06 0.04513 12000 101 462.61 0.04514 13000 101 501.16 0.04515 14000 101 539.71 0.04516 15000 102 578.26 0.09117 16000 103 616.81 0.136



18 17000 103 655.36 0.13619 18000 103 693.91 0.13620 19000 104 732.46 0.18221 20000 104 771.01 0.18222 21000 104 809.56 0.18223 22000 104 848.12 0.18224 23000 105 886.67 0.22725 24000 105 925.22 0.22726 25000 105 963.77 0.22727 26000 106 1002.32 0.27328 27000 106 1040.87 0.27329 28000 106 1079.42 0.273




Material: Brass (Sl.No.2)

1.Stress = P/A = Load in Kgs x 9.81 / Initial Area

2.Initial Area (Ai) = pidi2/4 = pi x (18.00)2/4 = 254.47 mm2 = 245.47 x 10-6 m2

3.Stress = 1000 x 9.81 / (245.47 x 10-6) = 38.55 x 106 N/m2

4.Change in Height = Scale reading Initial Scale reading = 100 100 = 0mm

5.Strain = Change in Height / Original Height = 0/ 21.16 = 0.00

6.Final area (Af) = pidf2/4 = pi x (21.6)2/4 = 401.15 mm2 = 388.15 x 10-6 m2

7. % increase in area = (Af Ai) x 100 / Ai = 44.00

8. % decrease in height = (hf hi) x 100 / hi = 23.73

9. Compressive Strength = Max. Load / Initial Area = 28000 x 9.81/ (245.47 x 10-6) = 10.79 x 108 N/m2

10. Modulus of elasticity (from graph) = 10.33 x 109 N/m2


B. Material: Mild Steel (For l.No.2)

1.Stress = P/A = Load in Kgs x 9.81 / Area

2.Initial Area (Ai) = pidi2/4 = pi x (18.00)2/4 = 254.47 mm2 = 245.47 x 10-6 m2

3.Stress = 1000 x 9.81 / (245.47 x 10-6) = 38.55 x 106 N/m2

4.Change in Height = Scale reading Initial Scale reading = 101 100 = 1mm



5. Strain = Change in Height / Original Height = 1/ 21.16 = 0.047

6. Final area (Af) = pidf2/4 = pi x (22.6)2/4 = 401.15 mm2 = 401.15 x 10-6 m2

7. % increase in area = (Af Ai) x 100 / Ai = 57.64

8. % decrease in height = (hf hi) x 100 / hi = 30.539. Maximum Compressive Strength = Max. Load / Initial Area

= 25000 x 9.81/ (245.47 x 10-6) = 9.64 x 108 N/m2

10. Modulus of elasticity (from graph) = 5.67 x 109 N/m2

SPECIMEN SKETCH

MATERIAL :DUCTILE MATERIAL :BRITTLEBEFORE TESTING BEFORE TESTING


AFTER TESTING AFTER TESTING


STRESS vs STRAIN GRAPH FOR BRASS MATERIAL

RESULT

SL. NO.

PARAMETER BRASS MILD STEEL

1. Decrease in height (%) 23.73 30.53

2 Increase in area (%) 44.00 57.64

3 Compressive strength ( N/m2) 10.7942x108 96.377x108

4 Modules of elasticity (N/m2) 1.033x109 5.67x109



EXPERIMENT No.S01&S02

PREPARATION OF SPECIMEN FOR METALLOGRAPHIC EXAMINATION & MICROSTRUCTURE STUDY OF THE ENGINEERING MATERIALS

Objective: To study the microstructure of the given specimen (micro-section) and to determine the grain size.

Apparatus: Hand press, flat file, emery papers of various grades, rotary polishing machine and metallurgical microscope.

Theory: Micrography is the study of the structures of metals and their alloys under a microscope at magnification from x75 to x1500. The observed structure is called the microstructure. The metallographic studies include;

1. Determination of size and shape of the crystallites, which constitute an alloy.2. Reveal the structure characteristic of certain type of mechanical working operations.3. Detect the micro-defects such as nonmetallic inclusions, micro cracks, etc.4. Determine the chemical content of alloy.5. It indicates the quality of heat treatment.Preparation of specimens for microscopical examination: The various steps involved in preparing a specimen for microscopic examination are given below.

1. Selection of specimen: When investigating the properties of a metal, it is essential that the specimen must be homogeneous in composition and crystal structure. A specimen of 10mm diameter or 10mm square is cut from the metal with a saw or water-cooled slitting wheel. The thickness of the specimen should not be more than 12mm. When a specimen is so small that it is difficult to hold, the specimen may be mounted in a suitable compound like thermoplastic resin, by using a hand press. In cases where neither pressure nor heating is desirable, a cold setting thermoplastic resin can be cast round the specimen, a specimen whose surface has been prepared for micro analyses is called micro-section.

2. Grinding: It is primarily necessary to obtain a reasonably flat surface of the specimen. This can be achieved either by using a fairly coarse file or by using motor-driven emery belt. Care must be taken to avoid overheating of the specimen by rapid grinding methods; since this may lead to alterations in the microstructure. When the original hacksaw marks have been ground out, the specimen should be thoroughly washed.

3. Fine grinding: Fine grinding is carried out on waterproof emery papers of progressively finer grades (220, 320, 400 and 600) that are attached to a plane glass plate. The specimen is drawn back and forth along the entire length of No. 220 paper, so that scratches produced are roughly at right angles to those produced by the preliminary grinding operation. Having removed the primary grinding marks, the specimen is washed thoroughly. Grinding is then continued on No. 320 paper and again turning the specimen through 900 until the previous scratch marks has been removed.



This process is repeated with No. 400 and No. 600 papers. Light pressure should be used at all stages.

4. Polishing: The final polishing operation is to remove the fine scratches on the surface by using a rotary polishing machine. The specimen is polished by rubbing it on a soft moist velvet cloth mounted on a flat rotating disc, with the polishing paste. Suitable polishing pastes are fine alumina, magnesia, Chromium oxide or diamond dust. Polishing is continued until a mirror scratch free finish is obtained. Non-ferrous specimens are best finished by hand on a small piece of selvyt cloth wetted with silvo polishing. This should be accomplished with a circular sweep of the hand instead of back and forth motion used in grinding. During polishing a constant trip of water is fed to the rotating pad. After polishing, the specimen must be washed thoroughly. The grease films if any can be removed by immersing the specimen in boiling ethanol.

5. Etching: To make its structure apparent under the microscope, it is necessary to impart unlike appearances to the constituents. This is generally accomplished by selectively corroding or etching the polished surface by applying a chemical etching reagent. Grain boundaries will etch at different rates than the grains, then leaving the grains standing out and they become visible with a reflected light microscope.



EXPERIMENT No. D03

HEAT TREATMENT OF STEEL MATERIALS & STUDY OF THEIR HARDNESS USING THEIR ROCK-WELL TESTING MACHINE

(ANNEALING AND NORMALIZING OF STEEL)

Objective: To heat treat the given steel specimen( anneal or normalize)and determine the Rockwell hardness.

Apparatus: Austenitizing furnace (upto-1000C) and Rockwell hardness testing machine.

Theory: The microstructure of steel part can be modified by heat treatment techniques, that is, by controlled heating and cooling of the alloys at various rates. These treatments induce phase transformations that greatly influence mechanical properties of steel. The various heat-treatment processes are annealing, normalizing, hardening and tempering.

Annealing of steel is the process of heating the steel specimen to its austenizing temperature, holding it there long enough to dissolve the cementite and disperse the carbon uniformly and then cool it very slowly to change the structure to the softest state. The low rate of cooling is achieved by turning the furnace off and letting the closed furnace cool down to ambient temperature. The annealing temperature of hypoeutectoid steel is

tanneal = Upper critical temperature + 30C to 50C

To avoid excessive softness in the annealing of steels, the cooling cycle may be done completely in still air. This process is called normalizing. In normalizing, the part is heated to normalizing temperature and is withdrawn from the furnace. It is then cooled in still air at the room temperature. The more drastically cooled austenite decomposes into a more dispersed aggregate made up of pearlite. After annealing and normalizing, a fine grain structure is obtained, provided there is no super heating. The normalizing temperature is usually 30C to 50C more than that of annealing temperature.

The purposes of annealing are:1. To obtain softness.2. To improve machinability.3. To increase ductility and toughness.4. To relieve internal stresses.5. To refine the grain size. .6. To prepare steel for subsequent cold working.

The purposes of normalizing the steel are:1. To eliminate coarse-grained structure obtained in previous working (rolling, forging or stamping). 2. To increase the strength of medium carbon steel.3. To improve machinability of low carbon steel.4. To reduce internal stresses.



Heat-treating furnace: A heat-treating furnace is a refractory lined chamber in which the metal parts are heated to the required temperature. Usually the furnace consists of a box-like structure of steel shell, door, refractory lining. heating source, temperature controls and temperature indicators.

Procedure for annealing:

1. Heat the given steel specimen in a box type furnace until the specimen reaches the annealing temperature.

2. keep the specimen in the furnace at the annealing temperature for some time3. Cool the specimen by switching off the furnace.4. Remove the steel specimen from the furnace when the furnace is cooled down to atmospheric

temperature.5. Determine the hardness of the annealed specimen using Rockwell hardness testing machine.

Procedure for normalizing:1. Heat the given steel specimen in a box type furnace until the specimen reaches the

normalizing temperature.2. keep the specimen in the furnace at the normalizing temperature for some time3. Remove the steel specimen from the furnace when the furnace is cooled down to

atmospheric temperature.4. Determine the hardness of the normalized specimen using Rockwell hardness testing

machine.



EXPERIMENT NO. MT05

WEAR TEST

AIM: To study the wear properties of the given specimen and to determine the wear rate.

APPARATUS/ TOOLS/ EQUIPMENT USED:

Wear testing machine Tachometer Scale Digital weighing machine Digital stopwatch.

THEORY: Wear is defined as the progressive loss or removal of material from a surface. Usually parts damaged by wear can be repaired or replaced before disastrous failure takes place. Wear is usually classified as adhesive, abrasive, corrosive, fatigue, fretting, and impact wear.Adhesive wear: If a tangential force is applied between the two sliding blocks, shearing can take place either at the original interfac

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