BS/EN 59-2016 pdf download.Glass reinforced plastics Determination of indentation hardness by means of a Barcol hardness tester.
6.2 Verification
Check the device by a measurement on a glass plate or a hardened steel plate so as to obtain a reading of 100 on the display.
In addition the calibrated reference plates made of aluminium are used for verification. These reference plates shall be calibrated In a calibration laboratory.
The deviation of a measurement on a reference plate is limited to a maximum of± 2 Barcol units.
The deviation of a measurement with the Barcol tester shall be maximum ± 1 Barcol unit.
The deviation due to the reference plate and the deviation due to measurement with the Barcol tester are
cumulative (so the overall deviation is maximum ± 3 Barcol units).
7 Conditioning and testing atmospheres
7.1 Condition the test specimens before testing in the atmosphere specilied in the relevant material specification. If no material specification exists, condition the test specimens in one of those specified in
EN ISO 291.
For testing in the standard atmosphere of (23 ± 2) °C/(50 ± 2) % RH. a conditioning time of 16 h may be selected.
7.2 Carry out the test in one of the standard atmospheres specified in EN ISO 291, unless otherwise specified in the relevant material specification.
When conditioning and testing in the specified standard conditions is not possible, this shall be stated in the test report.
8 Procedure
8.1 Place the test specimen on a stable and hard surface that it cannot be bent or deformed under the pressure of the Barcol hardness tester.
Curved surfaces can cause difficulties for placing the Barcol hardness tester properly. While the pressure is applied, the deflection or jerking stress of the test specimen should be avoided.
8.2 Position the Barcol hardness tester with the feet or by using a test stand so that the presser foot is positioned straight above the specimen.
The penetration of the indenter shall occur only when the indenter Is perpendicular to the surface of the test specimen.
In case of a small test specimen, it may be necessary to fit the Barcol hardness tester with one or two support feet so that the indenter can be positioned straight above the test specimen.
Impressions should not be made within 3 mm of the edge of the specimen or of other impressions.
8.3 Apply by hand a large and quick force, preferably 80 N, on the top cover of the Barcol hardness tester while the highest number on the display unit is recorded, preferably within 1 s after applying the force. The time period of 1 s starts as soon as the indenter’s movement exceeds S Barcol units.
A slow fall in the reading on the indicating dial is sometimes noted for materials which are susceptible to creep. It is particularly important for such materials to record the highest instantaneous reading on the indicating dial.
A sliding of the indenter on the test surface during the test shall be avoided.
NOTE For materials which are subject to deformation and cannot be fully restored, fluctuations can occur on the display during the measurement In such cases, it is important to detect the maximum value on the display.
An automatic registration of time and indentation depth at a sufficient data collection frequency with an analysis algorithm may be used to calculate the initial hardness value. Registration of time dependence indentation depth otTers the possibility to analyse and quantity the creep effects.
9 Number of measurements
Reinforced plastics materials are inherently heterogeneous and a large scatter of readings is observed. This is mainly caused by the differences in hardness between the resin and the reinforcement material in contact with the small diameter indenter. The number of measurements shall be such that the average result has a standard deviation oft 4 % (at a 95 % probability level).
10 Test report
The test report shall include the following information:
a) a reference to this European Standard (i.e. EN 59);
b) all details necessary for identification of the material tested;
c) a detailed description of the test specimen (5.2);
d) conditioning and testing conditions (Clause 7);BS/EN 59-2016 pdf download.
BS/EN 59-2016 pdf download
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