Plastics - Determination of tensile-impact strength (ISO 8256:2023)

1.1     This document 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 the ISO 179 series 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 are not necessarily the same. Equally, it is possible that specimens cut from moulded products will 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 can or can 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.

Kunststoffe - Bestimmung der Schlagzugzähigkeit (ISO 8256:2023)

Dieses Dokument legt zwei Verfahren (Verfahren A und Verfahren B) zur Bestimmung der Schlagzugzähigkeit von Kunststoffen unter festgelegten Bedingungen fest. Die Prüfungen können als Zugversuche mit verhältnismäßig hoher Verformungsgeschwindigkeit bezeichnet werden. Diese Verfahren können bei steifen Werkstoffen (wie in ISO 472 festgelegt) angewendet werden, sie sind jedoch besonders bei Werkstoffen von Nutzen, die für die Schlagbiegeprüfungen in Übereinstimmung mit der Normenreihe ISO 179 und nach ISO 180 zu flexibel oder zu dünn sind.
1.2   Diese Verfahren werden benutzt, um das Verhalten festgelegter Probekörper bei festgelegten Schlaggeschwindigkeiten zu untersuchen und die Sprödigkeit oder Zähigkeit von Probekörpern innerhalb der Grenzen der Prüfbedingungen festzustellen.
1.3   Diese Verfahren sind sowohl für Probekörper geeignet, die aus Formmassen hergestellt sind, als auch für Probekörper, die Formteilen und Halbzeugen entnommen sind (zum Beispiel aus Spritzgussteilen, Schichtstoffen oder aus extrudierten oder gegossenen Tafeln).
1.4   Ergebnisse, die bei der Prüfung von geformten Probekörpern unterschiedlicher Maße gewonnen wurden, sind nicht notwendigerweise gleich. Ebenso ist es möglich, dass die aus Formteilen ausgearbeiteten Probekörper nicht zu den gleichen Ergebnissen wie direkt aus der Formmasse geformte Probekörper gleicher Maße führen. An aus Formmassen hergestellten Probekörpern erhaltene Prüfergebnisse können nicht unmittelbar auf Formteile irgendeiner Form übertragen werden, da die Messwerte von der Formteilgestalt und den Bedingungen der Formgebung abhängen können. Ergebnisse nach Verfahren A und Verfahren B können vergleichbar sein oder nicht.
1.5   Diese Verfahren sind nicht als Datenquelle für Konstruktionsberechnungen von Teilen geeignet. Informationen über das spezifische Werkstoffverhalten können jedoch erhalten werden durch die Prüfung unterschiedlicher Probekörpertypen, die unter verschiedenen Bedingungen hergestellt wurden, und durch Prüfung bei verschiedenen Temperaturen. Die beiden verschiedenen Verfahren sind sowohl zur Produktionskontrolle als auch zur Qualitätskontrolle geeignet.

Plastiques - Détermination de la résistance au choc-traction (ISO 8256:2023)

1.1         Le présent document 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 à la série ISO 179 ou l’ISO 180.
1.2         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.
1.3         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, stratifiés, feuilles extrudées ou coulées).
1.4         Les résultats obtenus en soumettant à l’essai des éprouvettes moulées de différentes dimensions peuvent ne sont pas nécessairement identiques. De même, il se peut que des éprouvettes découpées dans des produits moulés ne pas donne 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.
1.5         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 8256:2023)

Standard ISO 8256:2004 določa metodi (metoda A in metoda B) za ugotavljanje natezno-udarne trdnosti polimernih materialov pod določenimi pogoji. Preskuse je mogoče opisati kot natezne preskuse pri sorazmerno visokih stopnjah deformacije. Metodi je mogoče uporabiti za toge materiale (kot je opredeljeno v standardu ISO 472), predvsem pa sta uporabni za materiale, ki so preveč prožni ali pretanki za preskušanje z udarnimi preskusi v skladu s standardom ISO 179 ali ISO 180.
Metodi se uporabljata za preiskovanje vedenja določenih vzorcev pod določenimi hitrostmi udarca in za ocenjevanje krhkosti ali žilavosti vzorcev v okviru omejitev preskusnih pogojev.
Metodi se uporabljata tako za vzorce, pripravljene iz materiala za oblikovanje, kot za vzorce končnih izdelkov ali polizdelkov (kot so odlitki, folije, laminati ali ekstrudirane oziroma vlite plošče).
Rezultati, pridobljeni s preskušanjem ulitih vzorcev različnih mer, nujno niso enaki. Prav tako vzorci, izrezani iz vlitih izdelkov, morda ne dajo enakih rezultatov kot vzorci enakih mer, vlitih neposredno iz materiala. Rezultatov preskusov, pridobljenih iz vzorcev, pripravljenih za zmesi za oblikovanje, ni mogoče uporabiti neposredno za odlitke poljubne oblike, saj so vrednosti lahko odvisne od zasnove odlitka in pogojev oblikovanja. Rezultati, pridobljeni z metodo A in metodo B, so lahko primerljivi ali ne.
Ti rezultati niso primerni za uporabo kot vir podatkov za konstrukcijske izračune komponent. Pridobiti je mogoče podatke o značilnem obnašanju materiala, vendar s preskušanjem različnih vrst preskušancev, pripravljenih pod različnimi pogoji, in s preskušanjem pri različnih temperaturah. Različni metodi sta primerni za nadzor proizvodnje in nadzor kakovosti.

General Information

Status
Published
Public Enquiry End Date
22-Nov-2022
Publication Date
11-Jan-2024
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
03-Jan-2024
Due Date
09-Mar-2024
Completion Date
12-Jan-2024

Relations

Overview

EN ISO 8256:2023 - Plastics - Determination of tensile-impact strength (ISO 8256:2023) is a CEN-endorsed international standard that specifies two tensile‑impact test methods (Method A and Method B) for assessing the tensile-impact strength of plastics. These are high‑strain‑rate tensile tests especially suited to materials that are too thin or too flexible for Charpy/Izod impact tests. The standard is intended for material characterization, production and quality control rather than for direct design calculations.

Key topics and technical requirements

  • Two test methods: Method A and Method B are defined for tensile‑impact testing; results from the two methods may not be directly comparable.
  • Test principle: Tensile tests at relatively high strain rates using a pendulum/striker and a crosshead to impose impact loading.
  • Apparatus: Requirements and descriptions for test machines, pendulum and striker, crosshead, clamping devices/jaws, and measuring instruments (micrometers, gauges).
  • Specimen types and preparation:
    • Applicable to moulding compounds and specimens taken from finished or semi‑finished products (mouldings, laminates, extruded/cast sheets).
    • Guidance on specimen shape, dimensions, machining, moulding, extrusion, and notching where applicable.
    • Consideration of anisotropy and conditioning (standard atmospheres).
  • Energy corrections:
    • Correction for plastic deformation and kinetic energy of the crosshead (Method A).
    • Crosshead‑bounce energy correction (Method B).
    • Procedures and annexes describe how to determine correction factors.
  • Results and statistics:
    • Calculation of corrected tensile‑impact energy and tensile‑impact strength.
    • Reporting principles, statistical parameters, number of significant figures and precision statements.
  • Limitations:
    • Test outcomes depend on specimen dimensions, moulding conditions and specimen source; results are not generally suitable as inputs to component design.

Applications and users

  • Practical uses:
    • Assessing material toughness or brittleness under high strain‑rate tensile loading.
    • Production control and quality assurance of plastics and polymer products.
    • Comparative material screening in R&D and failure analysis for thin or flexible plastics.
  • Typical users:
    • Materials testing laboratories, polymer manufacturers, compounders, quality engineers, product development teams, and certification/inspection bodies.

Related standards

Normative references cited include ISO 179 (Charpy), ISO 180 (Izod), ISO 291 (conditioning), ISO 294‑1/2 and ISO 295 (specimen moulding), ISO 472 (vocabulary), ISO 2818 (machining), and ISO 1268 (fibre‑reinforced plastics). These complement EN ISO 8256:2023 for specimen preparation and conditioning.

Standard
SIST EN ISO 8256:2024
English language
23 pages
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Frequently Asked Questions

SIST EN ISO 8256:2024 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Plastics - Determination of tensile-impact strength (ISO 8256:2023)". This standard covers: 1.1     This document 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 the ISO 179 series 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 are not necessarily the same. Equally, it is possible that specimens cut from moulded products will 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 can or can 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.

1.1     This document 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 the ISO 179 series 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 are not necessarily the same. Equally, it is possible that specimens cut from moulded products will 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 can or can 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.

SIST EN ISO 8256:2024 is classified under the following ICS (International Classification for Standards) categories: 83.080.01 - Plastics in general. The ICS classification helps identify the subject area and facilitates finding related standards.

SIST EN ISO 8256:2024 has the following relationships with other standards: It is inter standard links to SIST EN ISO 8256:2004. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.

You can purchase SIST EN ISO 8256:2024 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of SIST standards.

Standards Content (Sample)


SLOVENSKI STANDARD
01-februar-2024
Polimerni materiali - Določanje natezno-udarne trdnosti (ISO 8256:2023)
Plastics - Determination of tensile-impact strength (ISO 8256:2023)
Kunststoffe - Bestimmung der Schlagzugzähigkeit (ISO 8256:2023)
Plastiques - Détermination de la résistance au choc-traction (ISO 8256:2023)
Ta slovenski standard je istoveten z: EN ISO 8256:2023
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 8256
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2023
EUROPÄISCHE NORM
ICS 83.080.01 Supersedes EN ISO 8256:2004
English Version
Plastics - Determination of tensile-impact strength (ISO
8256:2023)
Plastiques - Détermination de la résistance au choc- Kunststoffe - Bestimmung der Schlagzugzähigkeit (ISO
traction (ISO 8256:2023) 8256:2023)
This European Standard was approved by CEN on 9 December 2023.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8256:2023 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 8256:2023) has been prepared by Technical Committee ISO/TC 61 "Plastics" in
collaboration with Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by SIS.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by June 2024, and conflicting national standards shall be
withdrawn at the latest by June 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 8256:2004.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 8256:2023 has been approved by CEN as EN ISO 8256:2023 without any modification.

INTERNATIONAL ISO
STANDARD 8256
Third edition
2023-11
Plastics — Determination of tensile-
impact strength
Plastiques — Détermination de la résistance au choc-traction
Reference number
ISO 8256:2023(E)
ISO 8256:2023(E)
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 8256:2023(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 . 2
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 .14
Bibliography .16
iii
ISO 8256:2023(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 2,
Mechanical behaviour, in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 249, Plastics, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 8256:2004), which has been technically
revised.
The main changes are as follows:
— the reference to ISO 3167 has been replaced with ISO 20753;
— Table 2 has been modified clarified;
— additional description on preparation methods for the specimen types in 6.2.1 has been given.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
INTERNATIONAL STANDARD ISO 8256:2023(E)
Plastics — Determination of tensile-impact strength
1 Scope
1.1 This document 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
the ISO 179 series 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 are not necessarily the
same. Equally, it is possible that specimens cut from moulded products will 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 can or can 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 documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 (all parts), Plastics — Determination of Charpy impact properties
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 295, Plastics — Compression moulding of test specimens of thermosetting materials
ISO 472, Plastics — Vocabulary
ISO 8256:2023(E)
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 13802, Plastics — Verification of pendulum impact-testing machines — Charpy, Izod and tensile
impact-testing
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 472 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
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
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
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.
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
ISO 8256:2023(E)
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
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