ISO 180:2019 pdf free download – Plastics一Determination of Izod impact strength.
7.2 Measure the thickness h and width b of each test specimen, in the centre, to the nearest 0,02 mm. In the case of notched specimens, carefully measure the remaining width bN to the nearest 0,02 mm.
In the case of injection-moulded specimens, it is not necessary to measure the dimensions of each specimen. It is sufficient to measure one specimen from a set to make sure that the dimensions correspond to those in Table 1. With multiple-cavity moulds, ensure that the dimensions of the specimens are the same for each cavity.
73 Check that the impact machine is able to perform the test with the specified velocity of impact and that it is in the correct range of absorbed energy W which shall be between 10 % and 80 % of the available energy at impact, E. If more than one of the pendulums conform to these requirements, the pendulum having the highest energy shall be used.
7.4 Determine the frictional losses and correct the absorbed energy in accordance with Iso 13802.
7.5 Lift the pendulum to the prescribed height and support it. Place the specimen in the vice and clamp it as shown in Figure 2. in accordance with 5.1.2. When determining the notched Izod impact strength, the notch shall be positioned on the side that is to be struck by the striking edge of the pendulum.
7.6 Release the pendulum. Record the impact energy absorbed by the specimen and apply any necessary corrections for frictional losses, etc. (see 1A).
7.7 Four types of break designated by the following code-letters may occur:
C Complete break: a break in which the specimen separates into two or more pieces
H Hinge break: an incomplete break, such that one part of the specimen cannot support itself above the horizontal when the other part is held vertically, which means less than 90° included angle
P Partial break: an incomplete break that does not meet the definition for hinge break
N Non-break: there is no break and the specimen is only distorted, possibly combined with stress whitening
8 Calculation and expression of results
8.1 Unnotched specimens
Calculate the Izod impact strength of unnotched specimens, a1u, expressed in kilojoules per square metre, using Formula (1)
j) the number of specimens tested;
k) the standard atmosphere used for conditioning and testing, plus any special conditioning treatment if required by the standard for the material or product;
l) the type(s) of failure observed;
m) the individual test results, presented as follows (see also Table 2):
1) group the results according to the three basic types of failure:
C complete break, including hinge break H
P partial break
N non-break
2) select the most frequent type and record the mean value x of the impact strength for this type of failure, followed by the letter C or P for the type of failure,
3) if the most frequent failure type is N, record the letter N only,
4) add (between brackets) the letter C, P or N for the second most frequent failure type, but only if its frequency is higher than 1/3 (if not relevant, insert an asterisk);
n) the standard deviations of the mean values, if required;
o) the date(s) of the test.