prEN ISO 8256
(Main)Plastics - Determination of tensile-impact strength (ISO/DIS 8256:2022)
Plastics - Determination of tensile-impact strength (ISO/DIS 8256:2022)
ISO 8256:2004 specifies two methods (method A and method B) for the determination of the tensile-impact strength of plastics under defined conditions. The tests can be described as tensile tests at relatively high strain rates. These methods can be used for rigid materials (as defined in ISO 472), but are especially useful for materials too flexible or too thin to be tested with impact tests conforming to ISO 179 or ISO 180.
These methods are used for investigating the behaviour of specified specimens under specified impact velocities, and for estimating the brittleness or the toughness of specimens within the limitations inherent in the test conditions.
These methods are applicable both to specimens prepared from moulding materials and to specimens taken from finished or semi-finished products (for example mouldings, films, laminates, or extruded or cast sheets).
Results obtained by testing moulded specimens of different dimensions may not necessarily be the same. Equally, specimens cut from moulded products may not give the same results as specimens of the same dimensions moulded directly from the material. Test results obtained from specimens prepared from moulding compounds cannot be applied directly to mouldings of any given shape, because values may depend on the design of the moulding and the moulding conditions. Results obtained by method A and method B may or may not be comparable.
These methods are not suitable for use as a source of data for design calculations on components. Information on the typical behaviour of a material can be obtained, however, by testing different types of test specimen prepared under different conditions, and by testing at different temperatures. The two different methods are suitable for production control as well as for quality control.
Kunststoffe - Bestimmung der Schlagzugzähigkeit (ISO/DIS 8256:2022)
Plastiques Détermination de la résistance au choc-traction (ISO/DIS 8256:2022)
L'ISO 8256:2004 spécifie deux méthodes (la méthode A et la méthode B) permettant de déterminer la résistance au choc-traction des plastiques dans des conditions définies. Les essais peuvent être décrits comme des essais de traction conduits à des vitesses de déformation relativement élevées. Ces méthodes peuvent être utilisées avec des matériaux rigides (tels que définis dans l'ISO 472) mais elles se révèlent particulièrement utiles dans le cas des matériaux trop flexibles ou trop minces pour être soumis aux essais de choc conformément aux ISO 179 et ISO 180.
Ces méthodes sont utilisées pour étudier le comportement d'éprouvettes spécifiées, à des vitesses de choc définies, et pour évaluer la fragilité ou la ténacité d'éprouvettes dans les limites spécifiques des conditions d'essai.
Ces méthodes sont applicables à la fois aux éprouvettes préparées à partir de matériaux pour moulage et aux éprouvettes prélevées dans des produits finis ou semi-finis (par exemple, objets moulés, films, stratifiés, plaques extrudées ou coulées).
Les résultats obtenus en soumettant à l'essai des éprouvettes moulées de différentes dimensions peuvent ne pas être nécessairement identiques. De même, des éprouvettes découpées dans des produits moulés peuvent ne pas donner les mêmes résultats que des éprouvettes de mêmes dimensions, moulées directement à partir du matériau. Les résultats d'essai provenant d'éprouvettes constituées de mélanges pour moulage ne peuvent pas être directement appliqués à des objets moulés d'une quelconque forme car les valeurs peuvent dépendre de la forme de l'objet moulé et des conditions de moulage. Les résultats obtenus par les méthodes A et B peuvent être comparables ou ne pas l'être.
Ces méthodes ne sont pas adaptées à une utilisation en tant que source de données pour les calculs effectués lors de la conception des pièces. Cependant, elles permettent d'obtenir des informations sur le comportement type d'un matériau si l'on soumet à l'essai divers types d'éprouvettes préparées dans des conditions différentes et si les essais sont conduits à différentes températures. Les deux méthodes décrites conviennent pour les contrôles de la production et les contrôles de la qualité.
Polimerni materiali - Določanje natezno-udarne trdnosti (ISO/DIS 8256:2022)
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN ISO 8256:2022
01-oktober-2022
Polimerni materiali - Določanje natezno-udarne trdnosti (ISO/DIS 8256:2022)
Plastics - Determination of tensile-impact strength (ISO/DIS 8256:2022)
Kunststoffe - Bestimmung der Schlagzugzähigkeit (ISO/DIS 8256:2022)
Plastiques Détermination de la résistance au choc-traction (ISO/DIS 8256:2022)
Ta slovenski standard je istoveten z: prEN ISO 8256
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
oSIST prEN ISO 8256:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN ISO 8256:2022
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oSIST prEN ISO 8256:2022
DRAFT INTERNATIONAL STANDARD
ISO/DIS 8256
ISO/TC 61/SC 2 Secretariat: SAC
Voting begins on: Voting terminates on:
2022-09-01 2022-11-24
Plastics — Determination of tensile-impact strength
Plastiques — Détermination de la résistance au choc-traction
ICS: 83.080.01
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
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STANDARDS MAY ON OCCASION HAVE TO
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Reference number
NATIONAL REGULATIONS.
ISO/DIS 8256:2022(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022
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oSIST prEN ISO 8256:2022
ISO/DIS 8256:2022(E)
DRAFT INTERNATIONAL STANDARD
ISO/DIS 8256
ISO/TC 61/SC 2 Secretariat: SAC
Voting begins on: Voting terminates on:
Plastics — Determination of tensile-impact strength
Plastiques — Détermination de la résistance au choc-traction
ICS: 83.080.01
This document is circulated as received from the committee secretariat.
COPYRIGHT PROTECTED DOCUMENT
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
© ISO 2022
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
NOT BE REFERRED TO AS AN INTERNATIONAL
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NATIONAL REGULATIONS.
Website: www.iso.org ISO/DIS 8256:2022(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
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RIGHTS OF WHICH THEY ARE AWARE AND TO
ii
© ISO 2022 – All rights reserved
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022
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oSIST prEN ISO 8256:2022
ISO/DIS 8256:2022(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principle . 2
5 Apparatus . 2
5.1 Test machine . 2
5.2 Pendulum and striker . 3
5.3 Crosshead . 3
5.4 Clamping devices/jaws . . 3
5.5 Micrometers and gauges . 3
6 Test specimens . 3
6.1 Shape and dimensions . 3
6.2 Preparation . 5
6.2.1 Moulding and extrusion compounds . 5
6.2.2 Sheets . 6
6.2.3 Fibre-reinforced resins . 6
6.3 Notching of specimens . . 6
6.4 Number of test specimens . 6
6.5 Anisotropy . 6
6.6 Conditioning. 7
7 Procedure .7
8 Determination of energy corrections . 8
8.1 Method A — Correction E due to the plastic deformation and the kinetic energy
q
of the crosshead . 8
8.2 Method B — Crosshead-bounce energy E . 8
b
9 Calculation and expression of results . 8
9.1 Calculation of corrected tensile-impact energy . 8
9.1.1 General . 8
9.1.2 Energy correction for method A . 8
9.1.3 Energy correction for method B . 9
9.2 Calculation of tensile-impact strength . 9
9.3 Statistical parameters. 9
9.4 Number of significant figures . 9
10 Precision . 9
11 Test report .10
Annex A (normative) Determination of correction factor for method A.11
Annex B (normative) Determination of bounce-correction factor for method B .15
Bibliography .17
iii
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oSIST prEN ISO 8256:2022
ISO/DIS 8256:2022(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 8256 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 2, Mechanical
properties.
This third edition cancels and replaces the second edition (ISO 8256:2004), which has been technically
revised.
The changes in the third edition are the following:
— Replacement of the reference to ISO 3167 by the reference to ISO 20753
— Better clarity in Table 2 — Specimen types and dimensions
— Additional description on preparation methods for the specimen types in chpt. 6.2.1
iv
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oSIST prEN ISO 8256:2022
DRAFT INTERNATIONAL STANDARD ISO/DIS 8256:2022(E)
Plastics — Determination of tensile-impact strength
1 Scope
1.1 This International Standard specifies two methods (method A and method B) for the
determination of the tensile-impact strength of plastics under defined conditions. The tests can be
described as tensile tests at relatively high strain rates. These methods can be used for rigid materials
(as defined in ISO 472), but are especially useful for materials too flexible or too thin to be tested with
impact tests conforming to ISO 179 or ISO 180.
1.2 These methods are used for investigating the behaviour of specified specimens under specified
impact velocities, and for estimating the brittleness or the toughness of specimens within the limitations
inherent in the test conditions.
1.3 These methods are applicable both to specimens prepared from moulding materials and to
specimens taken from finished or semi-finished products (for example mouldings, laminates, or
extruded or cast sheets).
1.4 Results obtained by testing moulded specimens of different dimensions may not necessarily be the
same. Equally, specimens cut from moulded products may not give the same results as specimens of the
same dimensions moulded directly from the material. Test results obtained from specimens prepared
from moulding compounds cannot be applied directly to mouldings of any given shape, because values
may depend on the design of the moulding and the moulding conditions. Results obtained by method A
and method B may or may not be comparable.
1.5 These methods are not suitable for use as a source of data for design calculations on components.
Information on the typical behaviour of a material can be obtained, however, by testing different types
of test specimen prepared under different conditions, and by testing at different temperatures. The two
different methods are suitable for production control as well as for quality control.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 179-1, Plastics — Determination of Charpy impact properties — Part 1: Non-instrumented impact test
ISO 179-2, Plastics — Determination of Charpy impact properties — Part 2: Instrumented impact test
ISO 180, Plastics — Determination of Izod impact strength
ISO 291, Plastics — Standard atmospheres for conditioning and testing
ISO 293, Plastics — Compression moulding of test specimens of thermoplastic materials
ISO 294-1, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 1: General
principles, and moulding of multipurpose and bar test specimens
ISO 294-2, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 2: Small
tensile bars
ISO 294-3, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 3: Small
plates
1
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oSIST prEN ISO 8256:2022
ISO/DIS 8256:2022(E)
ISO 295, Plastics — Compression moulding of test specimens of thermosetting materials
ISO 472, Plastics — Vocabulary
ISO 1268 (all parts), Fibre-reinforced plastics — Methods of producing test plates
ISO 2602, Statistical interpretation of test results — Estimation of the mean — Confidence interval
ISO 2818, Plastics — Preparation of test specimens by machining
ISO 10350-1, Plastics — Acquisition and presentation of comparable single-point data — Part 1: Moulding
materials
ISO 11403-3, Plastics — Acquisition and presentation of comparable multipoint data — Part 3:
Environmental influences on properties
ISO 13802, Plastics — Verification of pendulum impact-testing machines — Charpy, Izod and tensile
impact-testing
ISO 20753, Plastics — Test specimens
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
tensile-impact strength of unnotched specimens
a
tU
energy absorbed in breaking an unnotched specimen under specified conditions, referred to the
original cross-sectional area of the specimen
2
Note 1 to entry: It is expressed in kilojoules per square metre (kJ/m ).
3.2
tensile-impact strength of notched specimens
a
tN
energy absorbed in breaking a notched specimen under specified conditions, referred to the original
cross-sectional area of the specimen at the notch
2
Note 1 to entry: It is expressed in kilojoules per square metre (kJ/m ).
4 Principle
A specimen is broken by a single impact at the bottom of the swing of the pendulum of a tensile-impact
machine. The specimen is horizontal at the moment of rupture. One end of the specimen, at impact,
is held either by the frame or the pendulum and the other end by the crosshead. The two methods
described are based on two different ways of positioning the specimen held by the crosshead: the
specimen may be either mounted stationary on the support frame (method A) or carried downward
together with the pendulum (method B).
The energy to fracture is determined by the kinetic energy extracted from the pendulum in the process
of breaking the specimen. Corrections are made for the energy to toss (method A) or bounce (method B)
the crosshead.
5 Apparatus
5.1 Test machine
The principles, characteristics and verification of suitable test machines are detailed in ISO 13802.
2
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oSIST prEN ISO 8256:2022
ISO/DIS 8256:2022(E)
5.2 Pendulum and striker
5.2.1 The pendulum shall be constructed of a single- or multiple-membered arm holding the head,
in which the greatest mass is concentrated. A rigid pendulum is essential to maintain the proper
clearances and geometric relationships between related parts and to minimize energy losses, which
are always included in the measured impact-energy value.
5.2.2 The strikers for method A and method B are described in detail in ISO 13802.
5.3 Crosshead
5.3.1 As pointed out in ISO 13802, in order to reduce bouncing due to the impact of the metal striker
on the metal crosshead, the material used for the crosshead shall be one which gives an essentially
inelastic impact (e.g. aluminium). The mass of the crosshead, both for method A and for method B, shall
be selected from the values given in Table 1.
5.3.2 A jig or other device shall be used to assist in clamping the crosshead in the specified position,
at right angles to the longitudinal axis of the specimen.
Table 1 — Crosshead masses
Crosshead mass
Potential energy
g
J
Method A Method B
2,0 15 ± 1 or 30 ± 1 15 ± 1
4,0 15 ± 1 or 30 ± 1 15 ± 1
7,5 30 ± 1 or 60 ± 1 30 ± 1
15,0 30 ± 1 or 60 ± 1 120 ± 1
25,0 60 ± 1 or 120 ± 1 120 ± 1
50,0 60 ± 1 or 120 ± 1 120 ± 1
NOTE For method A, use the lighter crosshead whenever possible.
5.4 Clamping devices/jaws
Clamps and jaws for tensile-impact testing are described in ISO 13802.
5.5 Micrometers and gauges
Micrometers and gauges suitable for measuring the dimensions of test specimens to an accuracy of
0,01 mm are required. In measuring the thickness of the specimen, the measuring face shall apply a
load of 0,01 MPa to 0,05 Mpa. For notched specimens, see the requirements of 7.4.
6 Test specimens
6.1 Shape and dimensions
Five types of test specimen, as specified in Table 2 and shown in Figure 1, may be used. In general, all
types can be used with either of the two methods.
Method A: the preferred specimen types are type 1 and type 4.
Method B: the preferred specimen types are type 2 and type 4.
3
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oSIST prEN ISO 8256:2022
ISO/DIS 8256:2022(E)
The test result depends on the type of specimen used and its preparation and thickness. For
reproducible results, or in cases of dispute, the type of test specimen and its preparation and thickness
shall be agreed upon.
Specimens are tested at their original thickness up to and including 4 mm. The preferred specimen
thickness is 4 mm ± 0,2 mm for type 1 specimens and 3 mm ± 0,2 mm for type 4 specimens. Within
the gauge area, the thickness shall be maintained to within a tolerance of ±5 %. Above 4 mm, the test
methods described in this International Standard are inapplicable, and ISO 179 or ISO 180 have to be
used to determine the impact properties of specimens.
Table 2 — Specimen types and dimensions
...
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