1、BSI Standards PublicationBS ISO 12986-2:2014Carbonaceous materials used inthe production of aluminium Prebaked anodes and cathodeblocksPart 2: Determination of flexural strength bythe four-point methodBS ISO 12986-2:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation
2、 of ISO 12986-2:2014.It supersedes BS ISO 12986-2:2005 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee CII/24, Raw materials for the aluminium industry.A list of organizations represented on this committee can beobtained on request to its secretary.This
3、 publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 81220 0ICS 71.100.10Compliance with a British Standard cannot confer immu
4、nity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 July 2014.Amendments issued since publicationDate Text affectedBS ISO 12986-2:2014 ISO 2014Carbonaceous materials used in the production of aluminium Prebaked anodes
5、 and cathode blocks Part 2: Determination of flexural strength by the four-point methodProduits carbons utiliss pour la production de laluminium Anodes prcuites et blocs cathodiques Partie 2: Dtermination de la rsistance la flexion par la mthode quatre pointsINTERNATIONAL STANDARDISO12986-2Third edi
6、tion2014-06-15Reference numberISO 12986-2:2014(E)BS ISO 12986-2:2014ISO 12986-2:2014(E)ii ISO 2014 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2014All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means,
7、 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 ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Te
8、l. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 12986-2:2014ISO 12986-2:2014(E) ISO 2014 All rights reserved iiiContents PageForeword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 25 Apparatus . 26 Test speci
9、men 36.1 Sampling and sample preparation . 36.2 Size and geometry 47 Procedure. 48 Calculation and expression of results . 48.1 Bending moment, Mb48.2 Flexural strength, b59 Precision . 610 Test report . 6Bibliography 7BS ISO 12986-2:2014ISO 12986-2:2014(E)ForewordISO (the International Organization
10、 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
11、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 pro
12、cedures 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 documents should be noted. This document was drafted in accordance with the editor
13、ial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). 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. Details of any patent right
14、s identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an expla
15、nation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this docum
16、ent is ISO/TC 226, Materials for production of primary aluminium.This third edition cancels and replaces the second edition (ISO 12986-2:2009), which has been technically revised.ISO 12986 consists of the following parts, under the general title Carbonaceous materials used in the production of alumi
17、nium Prebaked anodes and cathode blocks: Part 1: Determination of bending strength by the three-point method Part 2: Determination of flexural strength by the four-point methodiv ISO 2014 All rights reservedBS ISO 12986-2:2014INTERNATIONAL STANDARD ISO 12986-2:2014(E)Carbonaceous materials used in t
18、he production of aluminium Prebaked anodes and cathode blocks Part 2: Determination of flexural strength by the four-point method1 ScopeThis part of ISO 12986 specifies a four-point method to determine the flexural strength of carbon and solid graphite materials at room temperature.NOTE This part of
19、 ISO 12986 is based on DIN 51944.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenc
20、ed document (including any amendments) applies.ISO 4288, Geometrical Product Specifications (GPS) Surface texture: Profile method Rules and procedures for the assessment of surface textureISO 7500-1, Metallic materials Verification of static uniaxial testing machines Part 1: Tension/compression test
21、ing machines Verification and calibration of the force-measuring systemISO 8007-1, Carbonaceous materials used in the production of aluminium Sampling plans and sampling from individual units Part 1: Cathode blocksISO 8007-2, Carbonaceous materials used in the production of aluminium Sampling plans
22、and sampling from individual units Part 2: Prebaked anodesISO 8007-3, Carbonaceous materials used in the production of aluminium Sampling plans and sampling from individual units Part 3: Sidewall blocks3 Terms and definitionsFor the purposes of this document, the following terms and definitions appl
23、y.3.1flexural strengthbmaximum flexural stress developed in a specimen during a flexural test to ruptureNote 1 to entry: The flexural strength is calculated as the quotient of the bending moment at maximum force, before or at rupture of the specimen under the conditions of the four-point method and
24、its section modulus.bb=MZwhere ISO 2014 All rights reserved 1BS ISO 12986-2:2014ISO 12986-2:2014(E)Mbis the bending moment at maximum force, in newton millimetres;Z is the section modulus, in cubic millimetres.Note 2 to entry: The flexural strength is expressed in megapascals (MPa).Note 3 to entry:
25、Generally, the maximum force displayed on the test machine and the force at fracture are similar; if they are different, the term refers to the maximum force displayed3.2bending momentMbcomponent of moment of force perpendicular to the longitudinal axis of a beam or a shaftNote 1 to entry: Mbis the
26、maximum moment at fracture, calculated from the maximum force displayed by the testing machine and the geometry of the test specimen. Generally, the maximum force displayed on the test machine and the force at fracture are similar; if they are different, the term refers to the maximum force displaye
27、d.3.3section modulusZratio of the second axial moment of area to the maximum radial distance of any point in the surface considered from the Q-axis with respect to which the second axial moment of area is definedNote 1 to entry: The section modulus can be expressed mathematically as shown in the fol
28、lowing formula.Z = Ia/rQ,maxwhereIais the second axial moment of area;rQ,maxis the maximum radial distance considered from the Q-axis with respect to which Iais defined.Note 2 to entry: The section modulus is calculated for the most common cross sections in Figure 2.4 PrincipleA bar-shaped test spec
29、imen is placed on two bearing blocks and a force is applied to its centre until the test specimen ruptures; the force is equally distributed on two points. The flexural strength is calculated from the maximum force, the distance between the load-bearing edges and the support, and the dimensions of t
30、he cross-section of the test specimen.5 Apparatus5.1 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 force edges.The device shall ensure a symmetrical force over the whole test length by mean
31、s of an appropriate self-adjusting system such as a cardanic suspension and movable support blocks; see Figure 1. The radius of curvature of the bearing blocks and of the force edges shall be in the range 2 mm to 5 mm.The distance between the support and between the force edges should be variable in
32、 order to adjust the measuring device to different sample geometries.2 ISO 2014 All rights reservedBS ISO 12986-2:2014ISO 12986-2:2014(E)5.3 Measuring device, (e.g. vernier calliper in accordance with ISO 13385-1) capable of measuring the linear dimensions of the test specimens with an accuracy of 0
33、,5.5.4 Measuring device, capable of measuring the surface roughness (peak-to-valley height) of test specimens.Key1 cardanic suspension2 force edges3 test specimen4 supportD diameter of test specimenF force, in newtonsh height of test specimenlssdistance between supportslsedistance between support an
34、d force edgeFigure 1 Example of a measuring device and test setup6 Test specimen6.1 Sampling and sample preparationSampling shall be in accordance with the appropriate method i.e. ISO 8007-1, ISO 8007-2, ISO 8007-3, or be agreed with the applicant. The number of specimens shall be defined with respe
35、ct to the homogeneity of the material to be tested.The side faces of the specimens shall be machined such that the surface roughness in terms of the peak-to-valley height Ra, when measured in accordance with ISO 4288, is smaller than 15 m. Depressions that can clearly be regarded as surface pores ar
36、e not considered. ISO 2014 All rights reserved 3BS ISO 12986-2:2014ISO 12986-2:2014(E)6.2 Size and geometryCylindrical or prismatic specimens can be used, provided that the smallest dimension be at least twice the diameter of the largest structural constituent (e.g. maximum particle size) of the mat
37、erial to be tested, but not smaller than 4 mm. The length of the specimens shall be at least 3,5 times their width or diameter.7 Procedure7.1 Perform all measurements at room temperature, i.e. in the range 10 C to 35 C.7.2 Choose the measuring range of the testing machine such that the expected load
38、 at failure is at least 1/10 of full scale. Centre the test specimen on the support, with the longitudinal axis perpendicular to the support edges. The width between supports shall be at least three times the width or diameter of the specimen. The distance between the force edges shall be equal to t
39、he width or diameter of the test specimen.In the case of prismatic specimens, ensure that the specimens rest entirely on the support edges, that at least one loading edge is movable and that the loading edges transmit the force uniformly over the whole width to the test specimens. In the case of cyl
40、indrical specimens, it is recommended that support edges be used with a diameter about 2 mm larger than the diameter of the test specimens to prevent the specimens from rolling away.Increase the force uniformly and shock-free at a rate (velocity of the force bearing) of about 5 mm/min or about 0,5 N
41、/mm2/s until the test specimen fractures. Determine the maximum force.8 Calculation and expression of results8.1 Bending moment, MbThe bending moment, Mb, is calculated according to Formula (1).MlFbse=2max(1)wherelseis the distance between the support and the force edge (leverage of force, see Figur
42、e 1), in mm;Fmaxis the maximum force, in N.4 ISO 2014 All rights reservedBS ISO 12986-2:2014ISO 12986-2:2014(E)8.2 Flexural strength, bThe flexural strength, b, in MPa is calculated using the formula in 3.1 and Formula (2).bse=lFZ2max(2)whereZ is the section modulus, in mm3(see Figure 2);lseis the d
43、istance between the support and the force-bearing edge (leverage of force, see Figure 1), in mm;Fmaxis the maximum force, in N.In the case of test specimens with square cross-section and lse= h, the flexural strength bin MPa is calculated according to Formula (3):b=32Fhmax(3)In the case of cylindric
44、al test specimens and lse= D, the flexural strength in MPa squared is calculated according to Formula (4):pib=162FDmax(4)a) Square b) Rectangle c) Circle d) RingZh=36Zbh=26ZD=pi332ZDdD=pi3244()KeyZ section moment, in mm3h height of a rectangular cross-section, in mmb breadth of a rectangular cross-s
45、ection, in mmD external diameter of a circular cross-section, in mmd internal diameter of a ring cross-section, in mmFigure 2 Calculation of section moments for cross-sections of the most common geometries ISO 2014 All rights reserved 5BS ISO 12986-2:2014ISO 12986-2:2014(E)9 PrecisionThe uncertainty
46、 of measurement when testing with this method of testing is approximately 5 % for a confidence level of 95 % under repeatability conditions for test pieces with dimensions of 30 mm 110 mm.10 Test reportThe test report shall contain the following information:a) a reference to this part of ISO 12986;b
47、) type, position and orientation of test specimens during the sampling procedure;c) designation of the test specimens;d) number of test specimens;e) linear dimensions of test specimens, in millimetres;f) flexural strength, b, in MPa, rounded to the nearest 0,1 MPa, individual values and mean value;g
48、) additionally agreed conditions deviating from this International Standard;h) test date.6 ISO 2014 All rights reservedBS ISO 12986-2:2014ISO 12986-2:2014(E)Bibliography1 ISO 13385-1, Geometrical product specifications (GPS) Dimensional measuring equipment Part 1: Callipers; Design and metrological
49、characteristics2 DIN 51944, Testing of carbonaceous materials Determination of flexural strength by four point method Solid materials ISO 2014 All rights reserved 7BS ISO 12986-2:2014ISO 12986-2:2014(E) ISO 2014 All rights reservedICS 71.100.10Price based on 7 pagesThis page deliberately left blankBSI is the national body responsible for preparing British Standards and other standards-related publications, information and services.BSI is incorporated by Royal Ch
