This document discusses different methods of hardness testing, including Brinell hardness testing, Rockwell hardness testing, Vickers hardness testing, and Shore hardness testing. Brinell hardness testing involves indenting a material with a 10mm diameter steel ball under a load and measuring the diameter of the indentation. Rockwell hardness testing uses different indenters and loads depending on the scale to measure depth of penetration. Vickers hardness testing uses a pyramid shaped indenter to measure hardness. Shore hardness testing provides an empirical hardness value for rubbers and elastomers using either the Shore A or Shore D scale.

1. MSE 2208
Materials Testing Sesssional
Presented by
Md. Abul Gofran Banna
Roll: 2027022
Department of Materials Science and Engineering
Khulna University of Engineering and Technology
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2. Hardness is the resistance of a
material to abrasion or localized
plastic deformation
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3. Hardness
 Hardness is not necessarily an indication of
strength , although for some materials such as
steel, a harder steel is a stronger steel.
 Measure of a material’s ability to resist surface
indentation or scratching.
 A difficult property to describe in terms of first
principles Φ value depends greatly on
method of testing.
 Different testing methods Φ different scales and
values.
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4. Hardness Testing
• Brinell Hardness Test: 10mm diameter ball
with a load of 500, 1000 or 3000kg
• Rockwell Hardness Test: A cone shape
indenter; the depth of penetration is measured.
• Vickers Hardness Test: Pyramid shape indenter
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5. Brinell Hardness Test (BHN)
F
Brinell’s Hardness
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6. Brinell’s Hardness Testing
P from 500 - 3000 kg
D= 10 mm
   
 
2 2
2
BHN P D D D d
  
  
 
 
d
D
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7. BHN Animation
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8. Brinell Test Protocol
1. Press a 10mm (3/8") diameter ball into
material with a known amount of load.
2. Measure diameter of the indentation.
3. BHN = Load = 2L
Surface Area D[D-(D2-d2)1/2]
a) L = Load placed on ball, usually 3000 kg , but 1500 kg, and
500 kg can also be used.
b) D = Diameter of steel ball ( = 10 mm)
c) d = diameter of dent, measured by looking thru a Brinell
microscope.
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9. Analysis of Plastic Deformation during
Brinell Hardness Test
Elastic
Plastic
H = Ae-BT
Mild steel
Copper
d / D ( % E )
H
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10. Limitations of the Brinell Hardness
Test
– Sample must be ten times thicker than the
indentation depth (sample usually should be at
least 3/8" thick).
– Test is most accurate if the indentation depth is 2.5
- 5.0 mm. Adjust load to achieve this.
– Test is no good if BHN > 650
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11. BHN PROS & CONS
• Widely used and well
accepted
• Large ball gives good
average reading with a
single test.
• Accurate
• Easy to learn and use
• Destructive
• Non-portable
• High initial cost
($5,000)
• Error due to operator
reading Brinell
Microscope (10% max)
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12. Rockwell Hardness Test
(HRb,HRc,etc.)
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13. Rockwell Hardness Method
Machine measures depth of penetration and computes
hardness
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14. Rockwell Hardness Method
• Select Scale - load and
indentor depending on the
scale
• Press a point into material
– - Diamond Point (Brale)
– - 1/16" ball
– - 1/8" ball
– - ¼” ball
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15. Symbol Minor(Pre-) Major(Total)
Indenter Load, kg Load, kg C1 C2mm-1
Coefficients in
R = C1 – C2 t
Normal Scales
RB, 1/16 ball*
RC, cone +
RA, cone
RD, cone
RE, 1/8 ball
RF, 1/16 ball
RG, 1/16 ball
Superficial Sales
R15N, cone+
R30N, cone
R45N, cone
R15T, 1/16 ball
R30T, 1/16 ball
R45T, 1/16 ball
10 100 130 500
10 150 100 500
10 60 100 500
10 100 100 500
10 100 130 500
10 60 130 500
10 150 130 500
3 15 100 1000
3 30 100 1000
3 45 100 1000
3 15 100 1000
3 30 100 1000
3 45 100 1000
Load levels and indenter sizes for Rockwell hardness tests.
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16. Rockwell Test Limitations
 Sample must be ten times thicker than the
indentation depth (sample usually should be
at least 1/8" thick).
 Need 3 tests (minimum) to avoid inaccuracies
due to impurities, hard spots.
 Test is most accurate if the Rockwell
Hardness is between 0 and 100. Adjust scale
to achieve this.
For Steel:
If HRa > 60, use HRc scale
If HRa < 60, use HRb scale
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17. PROS & CONS (RHT)
• Widely used and well
accepted
• Little operator
subjectivity
• Accurate
• Fast
• Destructive
• Non-Portable
• Initial cost ($5,000)
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18. Rockwell Readings to Brinell
1) If -20 < HRc < 40
BHN = 1,420,000
(100 – HRc)2
2) If 40 < HRc < 100
BHN = 25,000__
(100 - HRc)
3) If 35 < HRb < 100
BHN = 7,300____
(130 - HRb)
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19. Vickers Hardness Testing
Vickers Hardness = F/A = 3y
A
P
2
1.854P
HV
L

P: applied load in kg, 5-120 kg
L: average diagonal length, mm
(typically from a few µm to 1 mm)
q: angle between opposite faces of
indenter; 136°
Range: 5 (extremely soft metals) -
1500 (extremely hard materials)
q
DPH/VHN/VPH/VH = 2PSin(q/2)/L2
L
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20. Vickers Hardness Testing
• Continuous hardness from soft (5 DPH) to
hard materials (1500 DPH)
• DPH independent on load value unlike BHN
• Careful surface preparation required
• Slow due to careful measurement
• Small indentation compared to BHN
• Pin cushion and Barrel indentations possible
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21. Other types of HT
• Knoop hardness Test: Pyramid shape
indenter
• Scleroscope: rebound height
• Durometer: The resistance to penetration
(elastic deformation)
• Relationship between Hardness and
Strength
 
MPa
45
.
3
lb/in
500 2
in
in
K
where
HB
K
TS h
h



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22. Knoop Hardness Test
 Micro Hardness Tests
 Major : Minor = 7 : 1
 P : Applied load = 25 gf- 300 gf
 Ap : Unrecovered Proj. area of indentations, mm2
 L : Length of long diagonal, mm
 C : A constant supplied by the manufacturer
(C=0.07028 for 172° 30' between long edges and 130° 0' between
short edges)
2
14.2P
HK
L

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23. Pros & Cons (KHN)
• Accurate
• Useful for elongated
and anisotropic
constituents.
• Requires load to be
normal to surface plane
parallel surfaces.
• Can be done on
mounted specimens
• Slow
• Sensitive to surface
condition
• Subject to error in
diagonal measurement
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24. Comparison of HT Methods
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25. Shore (Durometer) Testing
 The Shore (Durometer) test provides an empirical hardness
value that doesn't correlate to other properties or fundamental
characteristics.
 Shore Hardness, using either the Shore A or Shore D scale, is
the preferred method for rubbers/elastomers and is also
commonly used for 'softer' plastics such as polyolefins,
fluoropolymers, and vinyls. The Shore A scale is used for
'softer' rubbers while the Shore D scale is used for 'harder'
ones.
 Because of the resilience of rubbers and plastics, the hardness
reading may change over time - so the indentation time is
sometimes reported along with the hardness number.
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26. Shore Tester
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27. Hardness Testing
• Indentation Hardness used for steel
– as opposed to scratch or rebound hardness
• It is indicative of ultimate tensile strength
– Atoms move out of the way to create indentation
• Two main types: Brinell and Rockwell
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28. Brinell Hardness
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29. Brinell Hardness
• A spherical indenter (1 cm diameter) is shot
with 29 kN force at the target
• Frequently the indenter is steel, but for harder
materials it is replaced with a tungsten carbide
sphere
• The diameter of the indentation is recorded
• The indentation diameter can be correlated
with the volume of the indentation.
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30. Brinell Hardness
BHN 
2P
D D D2
 d2
 
 
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31. Brinell Hardness
• ASTM and ISO use the HB value. It can be HBS (Hardness,
Brinell, Steel) or the HBW (Hardness, Brinell, Tungsten)
• HBW = 0.102 BHN
• Sometimes written as HBW 10/3000 (Tungsten, 10 mm
diameter, 3,000 kg force)
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32. Typical HB values
Material Hardness
Softwood (e.g., pine) 1.6 HBS 10/100
Hardwood 2.6–7.0 HBS 1.6 10/100
Aluminum 15 HB
Copper 35 HB
Mild steel 120 HB
18-8 (304) stainless steel annealed 200 HB
Glass 1550 HB
Hardened tool steel 1500–1900 HB
Rhenium diboride 4600 HB
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33. Rockwell Hardness
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34. Rockwell Hardness
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35. Rockwell Hardness Scales
Scale Code Load Indenter Use
A
HR
A 60 kgf 120° diamond cone
Tungsten
carbide
B
HR
B 100 kgf 1/16 in diameter steel sphere
Al, brass, and
soft steels
C
HR
C 150 kgf 120° diamond cone Harder steels
D
HR
D 100 kgf 120° diamond cone
E
HR
E 100 kgf 1/8 in diameter steel sphere
F HRF60 kgf 1/16 in diameter steel sphere
G
HR
G 150 kgf 1/16 in diameter steel sphere
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