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• Select the number of impacts n per measurement series by pressing the F4 key (see
section 6.4. "Number of readings per measurement series").
• Conduct impacts by cycling through the "1. load – 2. position – 3. trigger" mechanism:
1.
The impact device – while not in contact with the test piece – is held firmly with one
hand and the loading tube is depressed with the other hand until contact is felt.
2.
Position the support ring on the test piece. Take particular care to wholly seat the ring
on the test piece, but not coinciding with a previous test indentation.
3.
To trigger an impact, press the trigger button to release the impact body. To perform
another impact, repeat this cycle.
• After the last of the n impacts, the hardness average and further statistics of the measure
ment series are displayed.
Note: Make sure the loading tube is allowed to slowly return to the starting po-
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sition. Do take care the loading tube does not spring back uncontrolled, which
may result in permanent device damage.
Note: If possible, follow the standard practice of Leeb rebound hardness test-
ing as described in the standards DIN 50156-1 (metallic materials), ASTM A956
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(steel, cast steel and cast iron only), or other applicable standards. If these are
not available, the user is recommended to average a minimum of n = 3...5 im-
pacts at an indentation distance of 3 to 5 mm (0.12 to 0.20") for each location of
the sample that shall be tested.
Note: Do not carry out an impact in an area that has already been deformed by
another impact. Also, do not load the device when it is already positioned in the
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new test location, since the material under the device may be affected through
prior stress, and the catch chuck of the device may be damaged. The loading
movement can also be conducted in position after an impact (before the device
is moved to a new position), or in any location that shall not be tested later.
2.6. Testing light samples
In case samples are lighter than specified under section 2.3. "Test conditions" (1.5 / 5 / 15
kg) or sample sections have unfavourable mass distribution, they can go into vibration as the
impact body hits the test point. This entails unwanted energy absorption and thereby distorts
the test result. Therefore, such samples shall be supported by solid worktops. If the mass falls
below 0.5 / 2 / 5 kg but still exceeds 0.02 / 0.1 / 0.5 kg, "coupling" the sample to a larger mass
can help to prevent vibrations, where a rigid connection between the sample and a solid sup-
port is ensured. The following requirements must be met for coupling:
• The contact surface of the sample and the surface of the solid support must be level, flat
and ground smooth.
• The sample must exceed the minimum sample thickness for coupling (1 / 3 / 10 mm).
Follow the coupling procedure:
• Apply a thin layer of coupling paste to the contact surface of the sample.
• Press the sample firmly against the support.
• Rub the sample against the support in a circular motion.
Carry out the impact as usual, perpendicular to the coupled surface.
Note: Clamping may strain the sample, which can affect the hardness
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readings.
© 2012 by Proceq SA
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