The document discusses different hardness testing methods including Brinell hardness testing and Rockwell hardness testing. Brinell hardness testing involves pressing an indenter ball into the surface of a metal under a load and measuring the diameter of the indentation. Rockwell hardness testing measures the additional depth of a heavy load indenter beyond the depth of a previously applied light load. Both tests provide standardized hardness values and have advantages such as being simple and quick to perform.
This presentation is for mechanical engineering/ civil engineering students to help them understand the different type of destructive mechanical testing of materials. The tensile testing, hardness, impact test procedures are explained in detail.
Unit-II Mechanical Testing
Subject Name: OML751 Testing of Materials
Topics: Various Mechanical Tests [Hardness, Tensile, Impact, Bend, Shear, Creep & Fatigue]
B.E. Mechanical Engineering
Final Year, VII Semester, Open Elective Subject
[As per Anna University R-2017]
In these slides, an important mechanical property of Materials, that is HARDNESS, is discussed along with the different procedures which are used for determination of Hardness value of a certain material.
I hope, you'll find it helpful...!
This presentation is for mechanical engineering/ civil engineering students to help them understand the different type of destructive mechanical testing of materials. The tensile testing, hardness, impact test procedures are explained in detail.
Unit-II Mechanical Testing
Subject Name: OML751 Testing of Materials
Topics: Various Mechanical Tests [Hardness, Tensile, Impact, Bend, Shear, Creep & Fatigue]
B.E. Mechanical Engineering
Final Year, VII Semester, Open Elective Subject
[As per Anna University R-2017]
In these slides, an important mechanical property of Materials, that is HARDNESS, is discussed along with the different procedures which are used for determination of Hardness value of a certain material.
I hope, you'll find it helpful...!
Impact Testing of metals is performed to determine the impact resistance or toughness of materials by calculating the amount of energy absorbed during fracture. The impact test is performed at various temperatures to uncover any effects on impact energy. These services provide test results that can be very useful in assessing the suitability of a material for a specific application and in predicting its expected service life.
Unit-III Non Destructive Testing (NDT)
Subject Name: OML751 Testing of Materials
Topics: Various NDT tests [Visual inspection, Liquid penetrant test, Magnetic particle test, Thermography test, Radiographic test, Eddy current test, Ultrasonic test, Acoustic emission test]
B.E. Mechanical Engineering
Final Year, VII Semester, Open Elective Subject
[As per Anna University R-2017]
Impact Testing of metals is performed to determine the impact resistance or toughness of materials by calculating the amount of energy absorbed during fracture. The impact test is performed at various temperatures to uncover any effects on impact energy. These services provide test results that can be very useful in assessing the suitability of a material for a specific application and in predicting its expected service life.
Unit-III Non Destructive Testing (NDT)
Subject Name: OML751 Testing of Materials
Topics: Various NDT tests [Visual inspection, Liquid penetrant test, Magnetic particle test, Thermography test, Radiographic test, Eddy current test, Ultrasonic test, Acoustic emission test]
B.E. Mechanical Engineering
Final Year, VII Semester, Open Elective Subject
[As per Anna University R-2017]
Generally soaps create foam in water, but in present of some materials the foam creation is reduced and need more soap for producing foam, and this condition of water is called water hardness.
The presence of Calcium, Magnesium salt i.e. bicarbonates, sulphates, chloride in water is called causes of hardness of water. The water which contains these salts is called hard water. Hard water does not easily form lather with soap as the salt of Calcium and Magnesium react with soap to form insoluble organic salts.
The PHB-150 Pin Static Brinell hardness tester is designed following the Brinell hardness test method. The test force is controlled by a shear pin. After reading the diameter of the indention with the reading microscope, the Brinell hardness value can be obtained from the look up table.
1. OBJECT
The hardness test is a mechanical test for material properties which are used in engineering
design, analysis of structures, and materials development. The principal purpose of the
hardness test is to determine the suitability of a material for a given application, or the
particular treatment to which the material has been subjected. The ease with which the
hardness test can be made has made it the most common method of inspection for metals and
alloys.
Here I include some materials hardness testing experiment such as: brinell hardness testing, rockwell hardness testing, knoop and vickers hardness and impact test.
This part deals with the meaning of hardnbess. The importance of hardness and how to measure comparative values. Aportable apparatus can be used connected with a lap top or with any feasible means of recording the results can be appled.
The mechanical properties, i.e., yield strength of the material can be obtainedusing this NDT test without destructing the component by simply multiplying the reco9rded hardness reading by a constant depending on the carbon equivalent of the material.
2. For more help contact me
Muhammad Umair Bukhari
Engr.umair.bukhari@gmail.com
www.bzuiam.webs.com
03136050151
3. Hardness
The Metals Handbook defines hardness as
Resistance of metal to plastic deformation,
usually by indentation.
OR
The dictionary of Metallurgy defines the
hardness as the resistance of a material to
indentation.
4. Introduction to hardness testing..
Hardness has variety of meanings
Metal Industry resistance to
Metallurgist resistance to penetration
Mineralogist resistance to scratching
Machinist resistance to machining
5. Purpose of hardness testing
The principal purpose of hardness test is
to determine the suitability of a material for
a given application.
The ease with which the hardness test
is performed has made it the most
common method of inspection for metals
and alloys.
6. General types of hardness
testing…..
Current practice in USA divides hardness testing into
two categories:
Macrohardness:
Refers to testing with applied loads on the indenter of
more than 1 kg and material being tested are tools, dies
and sheet material in the heavier gages(in large scale)
Microhardness:
Refers to testing with applied loads are 1 kg or
below, and material being tested is very thin (down to
0.0125 mm or 0.0005 inch).
7. Hardness measuring mechanisms
Hardness is measured in a variety if ways.
Static indentation tests
Rebound tests
Scratch file tests
Ultrasonic test etc.
erosion test
abrasion tests
8. Static indentation test
A ball, cone, or pyramid is forced into the
surface of the metal being tested
The relationship of load to area or depth
of indentation is the measure of hardness,
such as in brinell, knoop, Rockwell and
Vickers hardness tests.
9. Brinell hardness
testing
INTRODUCTION:
A Swedish, J.A.Brinell, announced Brinell
hardness test. He pressed an indenter with a
hard ball to the surface of a metal. During
testing period, the weights were maintained
constant in indicated time. A low-order
microscope measured the diameters of
indentations. The values of diameters will be
transferred respectively into the value of
Brinell hardness, HB value.
10. Standard procedure..
That the test be made with
a ball of 10 mm diameter
under a load of 3,000 kg for
ferrous metals the loaded
ball is pressed into the
specimen for at least 10s.
But for non-ferrous these
parameter are different in
which load of 500 kg is
applied for 30s.
11. Contd…..
The diameter of the impression produced
is measured by means of a microscope
containing an ocular scale, usually
graduated in tenths of a millimeter,
permitting estimate to the nearest
0.05 mm.
12. Brinell hardness number
The Brinell hardness
number, or simply the
Brinell number, is
obtained by dividing the
load used, in kilograms,
by the actual surface
area of the indentation, in
square millimeters.
13. BHN = the Brinell hardness number
F = the imposed load in kg
D = the diameter of the spherical indenter in mm
Di = diameter of the resulting indenter impression in mm
14. A well structured Brinell hardness
number reveals the test conditions, and
looks like this, "75 HB 10/500/30" which
means that a Brinell Hardness of 75
was obtained using a 10mm diameter
hardened steel with a 500 kilogram load
applied for a period of 30 seconds.
15. Rockwell hardness
testing
INTRODUCTION:
S.P. Rockwell announced hardness test in 1919.
In the United States; however, it was used to
practical by C.H. Wilson.
Different weights composed of different material
indenters will inspire various usages. There are
two kinds of indenters, one is with a steel head
and the other is with a diamond head. Rockwell
hardness test is the most popular hardness test
nowadays.
16. Types of Rockwell testing
Rockwell testing:
In Rockwell testing the minor load is 10 kg
and major load (60, 100, or 150 kg) is
used regardless of the type of indenter.
Rockwell superficial testing:
In Rockwell superficial testing minor load
is 3 kg and major loads (15, 30 or 45 kg)
are used.
17. TEST PROCEDURE
Apply a minor load of 10 kg.
Then the dial is set to zero and then major load is
applied.
Then apply major load 60 to 150 kg according to the
scale used for 4 to 5 seconds.
Release the major load only.
Machine will show the Rockwell Hardness Number
HR on the machine.
All these operation will be done by machine
automatically.
100 number means most hard and 0 means least
hard
18. Rockwell test principle..
Itconsists of measuring the additional
depth of heavy load indenter beyond
the depth of previously applied light
load (minor).
20. Types of indenters used
Diamond cone indenters are used for
testing hard materials such as hardened
steel and cemented carbides.
Hardened steel ball indenter are used
for testing softer materials such as fully
annealed steel, softer grades of cast iron ,
wide variety of non-ferrous metals and
some non0metallic materials
21. Advantages of Rockwell hardness
testing:
The most widely used method for determining
hardness.
Simple to perform
Highly skilled operators are not required.
Different types of loads and indenters can
be used.
The entire operation completes within 10 sec.
Results are displayed digitally on the screen
22. Precautions
During manual operation, the work piece
should be raised very slowly with the
screw as it approaches the indenter.
The surface being tested must be
perpendicular to the direction of the force
on the indenter within 2-5 degree.
Careless operation in applying load, not
only result in accurate reading but can
damage the indenter.