GTBL042-07 GTBL042-Callister-v2 August 6, 2007 12:43
224 • Chapter 7 / Mechanical Properties
Table 7.5
Hardness-Testing Techniques
Shape of Indentation
Formula for
Test
Indenter
Side View
Top View
Load
Hardness Number
a
Brinell
10-mm sphere
of steel ortungsten carbide
D d
d
P
HB
=
2 P
π
D
[D
−
√
D
2 −
(^2) d
]
Vickers
microindentation
Diamond
pyramid
136
°
d^1
d^1
P
HV
854
P/
d
21
Knoop
microindentation
Diamond
pyramid
l/b
= 7.11
b/
t = 4.00
t
b
l
P
HK
14.2
P/l
2
Rockwell and
SuperficialRockwell
Diamond cone;
(^116)
,
1 , 8
1 , 4
1 , in. 2
diametersteel spheres
120
°
60 kg100 kg150 kg
⎫⎪⎬ ⎪⎭
Rockwell
15 kg30 kg45 kg
⎫⎪⎬ ⎪⎭
Superficial Rockwell
⎧⎪⎪⎨ ⎪⎪⎩
a
For the hardness formulas given,
P
(the applied load) is in kg, while
D, d, d
, and 1
lare all in mm.
Source:
Adapted from H. W. Hayden, W. G. Moffatt, and J. Wulff,
The Structure and Properties of Materials,
Vol. III,
Mechanical Behavior
. Copyright
c©
1965 by John Wiley & Sons, New York. Reprinted by permission of John Wiley & Sons, Inc.