•
193
Diamond
pyramid
Diamond
cone:
1 1 1 1
e 16
@, 8@, 4@, 2@ in.
diameter
steel spheres
Knoop
microhardness
Rockwell and
superficial
Rockwell
120°
l/b = 7.11
b/t = 4.00
136°
d
D
t
d1
l
d
Shape of Indentation
Side View
Top View
b
d1
15 kg
30 kg ¶ Superficial Rockwell
45 kg
60 kg
100 kg ¶ Rockwell
150 kg
P
P
P
Load
2P
pD[D - 2D2 - d 2]
HK = 14.2P/l2
HV = 1.854P/d21
HB =
Formula for
Hardness Number a
Source: Adapted from H. W. Hayden, W. G. Moffatt, and J. Wulff, The Structure and Properties of Materials, Vol. III, Mechanical Behavior. Copyright © 1965 by John
Wiley & Sons, New York.
For the hardness formulas given, P (the applied load) is in kg, and D, d, d1, and l are all in millimeters.
Diamond
pyramid
Vickers
microhardness
a
10-mm sphere
of steel or
tungsten carbide
Indenter
Brinell
Test
Table 6.5 Hardness-Testing Techniques