KERN & SOHN HMP - Manual (Page 4)

Sauter GmbH
Ziegelei 1
D-72336 Balingen
E-Mail: [email protected] Tel: +49-[0]7433- 9933-199
Fax: +49-[0]7433-9933-149
Internet: www.sauter.eu
Instruction Manual
HMP
HMP-BA-e-1211 4
To power on the instrument, the key has to be pressed
and held, meanwhile the key is also pressed. Then the
calibration screen is shown as on page 4.
5 points have to be tested on the standard hardness block.
After that, the average value of those 5 measured values
will be displayed. The keys and have to be
pressed to change its nominal value.
Finally the calibration has to be confirmed by pressing the
key. To cancel the calibration, the key has to be
pressed. Range of adjustment: ±30 HL
The measurement parameters, including the material
setting, the hardness scale and the impact direction, can’t
be changed during calibration.
3.2 Impact Device Selection
For the selection of impact devices, please refer to
APPENDIX Table 1 and Table 3.
3.3 Preparation of the Sample Surface
Preparation of the sample surface should conform to the
relative requirements in APPENDIX Table 3.

During the preparation of the sample surface,
any heating or cold processing on this surface
should be avoided.

Too big roughness of the surface being
measured could cause errors. The surface of the
sample should show metallic luster, be smooth
and polished, without any stains of oil etc.

Support of the sample is not necessary for
heavy objects. Medium-weight samples have to
be placed onto a smooth and stable plane. It
must be placed in absolute equability and
without any wobble.

Curved surface: The best testing surface, of
course, is flat. When the curvature radius R of
the surface to be tested is smaller than 30 mm
(D, DC, D+15, C, E and DL type of impact
device) and smaller than 50 mm (G type of
impact device), the small support rings should
be chosen.

The sample should have enough thickness, the
minimum thickness of it should conform to
Table 3.
*For a sample with a hardened layer on its surface,
the depth of the hardened layer should also conform
to Table 3.

Coupling: Light-weight samples must be firmly
coupled with a heavy base plate. Both coupled
surfaces have to be flat and smooth; there may
not rest any redundant coupling agent. The
impact direction must be vertical to the coupled
surface. If the sample is a big plate, long rod or
bending piece, it can be deformed and become
unstable, even though its weight and thickness
is big enough; accordingly, the test value might
not be accurate. So the sample should be
reinforced or supported at its back.
 Magnetism of the sample itself should be
avoided.
4. Testing Program
4.1 Start-up

The plug of the impact device has to be inserted
into the socket of the impact device of the
instrument.
 The key has to be pressed to power on. Now
the instrument is in working mode.
4.2 Testing
- The release button on the upside of the impact device
has to be pressed to start testing. The sample and the
impact device as well as the operator are all required to be
stable now. The action direction should pass the axis of
the impact device.
- Each measurement area of the sample usually needs 3
to 5 times of testing operations. The result data dispersion
should not be more than the mean value ± 15 HL.
- The distance between any two impact points or from the
centre of any impact point to the edge of the sample
should conform to the regulation of Table 4-1.
- If an accurate conversion from the Leeb hardness value
to another hardness value is requested, a contrastive test
is needed to get conversion relations for the special
material. An inspected qualified Leeb hardness tester and
a corresponding hardness tester have to be used to test at
the same sample respectively. For each hardness value,
each homogeneous measurement, 5 points of Leeb
hardness value are needed. They are in the surroundings
of more than three indentations which need conversion of
hardness. The Leeb hardness arithmetic average value
and the corresponding hardness average value as
correlative value respectively are used to establish an
individual hardness contrastive curve. The contrastive
curve at least should include three groups of correlative
data.