ISO 12986-2:2005

INTERNATIONAL ISO
STANDARD 12986-2
First edition
2005-02-15
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 12986-2:2005(E)
©
ISO 2005

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ISO 12986-2:2005(E)
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ISO 12986-2:2005(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
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ISO 12986-2 was prepared by Technical Committee ISO/TC 226, Materials for the production of primary
aluminium.
ISO12986 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
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ISO 12986-2:2005(E)
Introduction
[5]
This part of ISO 12986 is based on DIN 51944 .
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INTERNATIONAL STANDARD ISO 12986-2:2005(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
1Scope
This part of ISO 12986 specifies a four-point method to determine the flexural strength of carbon and solids
graphite materials at room temperature.
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 6906, Vernier callipers reading to 0,02 mm
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
bB
quotient of the bending moment, at fracture of the specimen under the conditions of the four-point method, and
its section moment
M
B
σ = (1)
bB
W
where
M is the bending moment, in newton millimetres;
B
W is the section moment, in cubic millimetres.
NOTE 1 It is expressed in newtons per square millimetre.
NOTE 2 Generally the maximum load displayed on the test machine and the load at fracture are similar; if they are
different, the term refers to the maximum load displayed.
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ISO 12986-2:2005(E)
3.2
bending moment
M
B
maximum moment at fracture, calculated from the maximum load displayed by the testing machine and the
geometry of the test specimen
NOTE Generally the maximum load displayed on the test machine and the load at fracture are similar; if they are different,
the term refers to the maximum load displayed.
4Principle
A bar-shaped test specimen is placed on two bearing blocks and its centre is loaded until the test specimen
ruptures; the load is equally distributed on two points. The flexural strength is calculated from the load at
fracture, the distance between the load-bearing edges and the points of support, and the dimensions of the
cross-section of the test specimen.
5 Apparatus
5.1 Compression-testing machine, which meets at least the demands of class 2 in accordance with
ISO 7500-1.
5.2 Measuring device with two bearing blocks and two loading edges.
The device shall guarantee a symmetrical load over the whole test lengt
...