ISO 12986-2:2009

INTERNATIONAL ISO
STANDARD 12986-2
Second edition
2009-06-15

Carbonaceous materials used in the
production of aluminium — Prebaked
anodes and cathode blocks —
Part 2:
Determination of flexural strength by the
four-point method
Produits carbonés utilisés pour la production de l'aluminium — Anodes
précuites et blocs cathodiques —
Partie 2: Détermination de la résistance à la flexion par la méthode
quatre points




Reference number
ISO 12986-2:2009(E)
©
ISO 2009

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ISO 12986-2:2009(E)
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ii © ISO 2009 – All rights reserved

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ISO 12986-2:2009(E)
Contents Page
Foreword .iv
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Principle.2
5 Apparatus.2
6 Test specimen.3
6.1 Sampling and sample preparation.3
6.2 Size and geometry.4
7 Procedure.4
8 Calculation and expression of results .4
8.1 Bending moment, M .4
b
8.2 Flexural strength, σ .4
b
9 Precision.5
10 Test report.5
Bibliography.7

© ISO 2009 – All rights reserved iii

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ISO 12986-2:2009(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
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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 12986-2 was prepared by Technical Committee ISO/TC 226, Materials for the production of primary
aluminium.
This second edition cancels and replaces the first edition (ISO 12986-2:2005), which has been technically
revised.
ISO 12986 consists of the following parts, under the general title Carbonaceous materials used in the
production of aluminium — Prebaked anodes and cathode blocks:
⎯ Part 1: Determination of bending/shear strength by a three-point method
⎯ Part 2: Determination of flexural strength by the four-point method

iv © ISO 2009 – All rights reserved

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INTERNATIONAL STANDARD ISO 12986-2:2009(E)

Carbonaceous materials used in the production of aluminium —
Prebaked anodes and cathode blocks —
Part 2:
Determination of flexural strength by the four-point method
1 Scope
This part of ISO 12986 specifies a four-point method to determine the flexural strength of carbon and solid
graphite materials at room temperature.
NOTE ISO 12986 is based on DIN 51944.
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 4288, Geometrical Product Specifications (GPS) — Surface texture: Profile method — Rules and
procedures for the assessment of surface texture
ISO 7500-1, Metallic materials — Verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines — Verification and calibration of the force-measuring system
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
flexural strength
σ
b
maximum flexural stress developed in a specimen during a flexural test to rupture
NOTE 1 Adapted from ISO 472:1999. The definition is identical to that in ISO 472:1999; the symbol has been added.
NOTE 2 The flexural strength is calculated as the quotient of the bending moment at fracture of the specimen under
the conditions of the four-point method and its section modulus.
M
b
σ = (1)
b
Z
where
M is the bending moment at rupture, in newton millimetres;
b
Z is the section modulus, in millimetres cubed.
NOTE 3 The flexural strength is expressed in newtons per millimetre squared.
© ISO 2009 – All rights reserved 1

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