User manual

Sauter GmbH
Tieringerstr. 11-15
D-72336 Balingen
E-Mail: [e-mail]
Tel: +49-[0]7433- 9976-174
Fax: +49-[0]7433-9976-285
Internet: www. sauter.eu
Instruction Manual
HMM
HMM-BA-e-1111 6
6.2 Sample Preparation
Inappropriate samples will cause great measurement
errors. Therefore, preparation and the necessary handling
should be done under original conditions of the sample.
Preparation of the sample and surface of test should be
coincident with the following basic requirements:
1) Cold processing and thermal processing of the impact
device during the process of sample surface preparation
should be avoided.
2) The surface of the sample should be plane, with a
metallic sheen, and not involve oxide layer or other stains.
3) Roughness of the test surface: Ra≤ 1.6
4) The sample has to be of sufficient quality and rigidity.
Otherwise displacements or shaking during the test might
happen. These could also lead to measurement errors.
A sample quality of ≥ 5 kg can be directly tested. If the
sample quality is 2~5 kg, it should be fixed before the test
by appropriate clamps. If the sample quality is 0.05~2 kg, it
should be coupled before the test; if it is < 0.05 kg, this
hardness tester is inappropriate to use.
Coupling method: The testing sample’s back should be
plane as well as the surface of the supporting object.
A little coupling substance (i.e. Industry Vaseline) has to
be filled between the two components. Then the two parts
have to be pressed together. If the weight of the supporting
object is more than 5 kg, it can be replaced by the test
block.
5) Samples should be thick enough with sufficient layered
surface. If the D-type of impact sensor is used, the
thickness of the sample should be less than 5 mm and the
surface absorption layer (surface- hardening layer) should
not be less than 0.8 mm. To perform accurate hardness
measurements, the best way is to remove this layer before
testing.
6) If the testing sample surface isn’t horizontal and flat, the
curvature radius of the testing and nearby surface should
be larger than 30 mm. An appropriate supporting ring has
to be selected and installed.
7) A sample should not be magnetic. The signal of the
impact sensor would be seriously affected, which might
cause inaccurate test results.
7. Test Steps
1) Loading:
The loading tube has to be slided forward to load the
impact device.
2) Placing:
The impact device has to be placed and held on the
surface of the test piece at the desired test point. Impact
direction should be vertical with the surface being tested.
3) Measuring:
The trigger button has to be pressed to trigger the impact
device. The hardness value will be immediately displayed.
4) Reading the test result
The test result has to be read as shown in picture 6-4:
Sample Material: steel and cast iron
Impact direction: downwards
Date: 3
rd
, December
Current hardness value: 786 HLD
The current measurement is the third point
Current mean value: 785 HLD
Conversions to HRC: 58.6 HRC
Mean value of HRC: 58.5 HRC
Repeating the above steps, tests in more points can be
carried out.
Note: Generally, each measurement location of sample
is conducted for five tests. The X (difference of max.
value and the min. value) values must be less than 15
HL. The distance between any two impact positions
should be ≥ 3mm; the distance between impact
position and the edge of the sample should also be
≥ 3mm.
7. Troubles and solutions