9
Materials
Range of
hardness
(HBW)
Specimen
thickness
(mm)
F/D
2
Ball diameter
(mm)
Test force F
(Kgf)
Test force
retaining time (s)
Ferrous metals
140-650
＞
6
F/D
2
=30
10
3000
12
6-3
5
750
＜
3
2.5
187.5
Ferrous metals
＜
140
＞
6
F/D
2
=30
10
3000
30
6-3
5
750
＜
3
2.5
187.5
Non-ferrous metal and alloys
(copper, bronze and others)
31.8-140
＞
6
F/D
2
=10
10
1000
30
6-3
5
250
＜
3
2.5
62.5
Nonferrous metals and alloys
(aluminum bearing alloy)
8-35
＞
6
F/D
2
=2.5
10
250
60
6-3
5
62.5
＜
3
2.5
15.6
It can be understood from the above table that the tungsten carbide balls and test forces can be selected randomly
for Brinell Hardness Test. However, if you adopts different tungsten carbide balls with different diameters and
apply different test forces to the same specimen, only when the ratio of test force against the square of ball
diameter is a constant, is it possible to obtain the same hardness or comparable results
Cleaning: Remove the antirust grease with acid-free gasoline and clean it with cotton or soft gauze.
B. Fitting indenter
(1) Fit the indenter and tighten the screw lightly.
(2) Place the standard hardness block onto the work table.
(3) Turn hand wheel to raise up the work table until the hardness block is pressed against the indenter.
(4) Tighten the screw so that it is tightly pressed against the flat part of fixing rod.
C. Selection of test forces:
(1) Select test forces as per Table 4.
(2) Selection of test force retaining time: First turn power on, and select the retaining time as per Table 4. The
retaining time can be regulated from 4 seconds to 99 seconds.
D. The specimen shall meet the following requirements:
(1) The specimen shall be polished so that the edges of indentation are visible enough to ensure the precision of
indentation measurement. Also its surface shall be free from oxide skins, electroplated layers oil dirt and any
surface defects.
(2) The surface to be tested shall be parallel to the supporting face so that the test force is perpendicularly applied
to the specimen surface.
(3) The thickness of specimen shall be no less than 10 times to the depth of indentation. In special cases stipulated
in Technical Document, the thickness may be at least no less than 8 times to the depth of indentation. The depth of
indentation
h
shall be that: h = 0.102F/
π
D. If deformations are found at the edges of specimen and its back face,
the test shall be regarded invalid and new test shall be done with smaller ball indenter and relevant test force.
(4) The distance between the centers of indentations and edges of specimens shall be no less than 2.5 times to the
diameter of indentation. The distance between the centers of two adjacent indentations shall be more than 4 times
to the diameter of indentation. Besides, the distances shall be larger than specified herein for soft metals.
(5) After test, the diameters of indentations shall be 0.24D
＜
d
＜
0.6D. Otherwise, the test results are invalid and
new test shall be done with corresponding test forces.
(6) During the process of testing, the axial line of indenter must be perpendicular to the specimen or its tested
surface. The test forces shall be applied stably, without any impact or vibration.
(7) The diameter of indentation shall be measured along two directions perpendicular to each other and their
