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Ref. No.: lSO/R 179-1961 (E)
IS0
I N T ERN AT I ON A L
ORGAN IZAT I ON FOR STAN DARD IZATl O N
IS0 RECOMMENDATION
O
R 179
PLASTICS
DETERMINATION OF THE CHARPY
IMPACT RESISTANCE OF RIGID PLASTICS
(CHARPY IMPACT FLEXURAL TEST)
1st ED IT1 ON
February 1961
COPYRIGHT RESERVED
IS0 Recommendations and IS0 Standards
The copyright of
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
Fox each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 179, Determination of the Charpy Impact Resistance of
Rigid Plastics (Charpy Impact Flexural Test), was drawn up by Technical Committee,
ISO/TC 61, Plastics, the Secretariat of which is held by the American Standards
Association, Incorporated (ASA).
Work on this matter which the Technical Committee had begun since 1956, came to
an end in 1957, with the adoption of a proposal as a Draft IS0 Recommendation.
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On 8 May 1959, the Draft IS0 Recommendation (No. 213) was distributed to all the
IS0 Member Bodies and was approved by the following Member Bodies:
Austria India Sweden
Belgium Israel Switzerland
Burma Italy Turkey
Czechoslovakia Japan United Kingdom
Finland
Netherlands U.S.A.
Germany Portugal U.S.S.R.
Greece Romania
Hungary Spain
One Member Body opposed the approval of the Draft: France.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0
Council, which decided, in February 1961, to accept it as an IS0 RECOMMENDATION.
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IS0 / R 179-1961 (E)
IS0 Recommendation R 179 February 1961
PLASTICS
DETERMINATION OF THE CHARPY*
IMPACT RESISTANCE OF RIGID PLASTICS
(CHARPY IMPACT FLEXURAL TEST)
1. DEFINITIONS
1 .I Impact strength of unnotched specimens. The impact energy consumed by the unnotched
specimen, referred to the cross section of the specimen (see clause 9.1).
1.2
Impact strength of notched specimens. The impact energy consumed by the notched
specimen (see Fig. 1 and 2), referred to the cross section of the specimen at the notch
before the test (see clause 9.2).
1.3 Relative impact strength. The ratio of the impact strength of notched specimens to
the impact strength of unnotched specimens (see clause 10.2.4).
1.4 Rigid plastics. For the purpose of this IS0 Recommendation, plastics that break under
the conditions of this test.
2. SCOPE
2.1 The impact flexural test is used for the determination of the behaviour of specified speci-
mens under specified impact stresses and for the estimation of the brittleness or of the
toughness of the specimens within the limitations applied by the conditions of the test.
The impact flexural test specified by this method is applied to specimens prepared from
2.2
moulding materials or taken from mouldings (including laminates). The test is particularly
suited for the control of the production and manufacture, as well as for the inspection
and acceptance of moulding materials and mouldings.
The test results obtained by testing specimens separately prepared from moulding materials
cannot be simply related to mouldings of other shapes, since the results of these tests depend
on the shape of the moulding and the conditions of their production.
A comprehensive estimation of the behaviour of moulded materials under impact flexural
stresses is only possible if the test described here is accompanied by other tests carried out
with differently shaped and dimensioned specimens and with different impact speeds of
the striker, as well as with different specimen arrangements and at different temperatures.
* For the determination of the Izod impact resistance, see IS0 Recommendation R 180, Determination af the Izod Impact Resistance of
Rigid Plastics (Izod Impact Flexural Tests).
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lPU/ K 1IY-1W1 (tl
3. TEST SPECIMENS
3.1 Unnotched specimens. The! determination of the impact strength of unnotched specimens
should be effected with t e specimen shapes according to Table 1, below. Specimens of
laminated sheets should b,e h taken so that the impact flexural test can be carried out with
impact direction lengthwife, as well as crosswise to the laminations.
Notched specimens. Notc ed specimens should be taken from the unnotched specimens
3.2
b
in accordance with table^ 1, notches being milled in accordance with Figures 1 and 2,
below. I
, TABLE 1.-Dimensions of spechens
'
Thickness h
Length Breadth b
(height)
Shape of specimen
mm mm mm
,
Standard bar I 120 2 15 f 0.5 10 & 0.5"
Standard small bar 50 f 1 6 f 0.2 4 f 0.2
,
Rounding off of the
notch base < 0.2
FIO. 1 .Sddard bar with notch
Dimensions in millimetres
Rounding off of the
notch base < 0.1
FIG. 2.Standarqh small bar with notch
* SecNote 1, page 7.
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IS0 I R 179 - 1961 (E)
The specimens are provided with a U-notch vertical to the axis of the bar. Position and
dimensions of the notch are I indicated in Figures 1 and 2. The depth of the notch should
be selected so that the remaining cross-section amounts to about 2/3 of the original total
cross-section of the bar, in the case of the standard test bar, for instance, about 1 cm2.
The edges of the notch base should not be rounded, if possible. The rounding radius of
these edges in standard test bars should remain below 0.2 mm, while in the standard small
bar it should not reach 0.1 mm (see Fig. 1 and 2).
3.2.1 In the case of specimens taken from laminated sheets, the notch should be cut into one
of the surfaces of 15 mm width as well as into one of the surfaces of 10 mm width, as
indicated in Figures 3 and 4.*
NOTES
In the case of specimens cut from laminated sheets, the thickness up to 10 mm is the same
1.
as that of the sheets. Specimens taken from sheets thicker than 10 mm should be milled
off uniformly from both sides to a thickness of 10 f0.5 mm. Specimens are not taken
5 mm thick.
from sheets less than
2. The dimension indicating the length of the notch is added as index value to uk.
RG. 3.-Notched standard bar
taken from laminated materials for
the determination of the impact
strength ak 15 *
Notch base perpendicular to
the laminations. Direction of
impact parallel to the laminations.
Dimensions in millimetres
FIG. 4.-Notched standard ,’ bar
taken from laminated materials for
the determination of the impact
strength ak 10 *
Notch base parallel to the
laminations. Direction of impact
perpendicular to the laminations.
* See Note 2.
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IS0 / R 179-1961 (E) *
I
3.3 Application of different s cimen shapes. The specimen shape to be selected should be
subject to agreement. acking agreement, ,the following specimens are used for
1
comparative investigation$, e.g., as basis for the classification of moulding materials and
mouldings :
(a) the standard bar,
ut or with notch, usually used for moulded specimens and spe-
cimens from
(6) the standard small b
without or with notch, for specimens cut from mouldings
(otherwise usually for specimens prepared by injection moulding).
44 NUMBER OF TEST SPECIMENS
The number of specimens to be tested should be subject to agreement. Lacking agreement,
4.1
five specimens should be ~tested.
4.2 For materials whose values are clearly dependent on direction
...