EN ISO 643:2012
(Main)Steels - Micrographic determination of the apparent grain size (ISO 643:2012)
Steels - Micrographic determination of the apparent grain size (ISO 643:2012)
ISO 643:2012 specifies a micrographic method of determining apparent ferritic or austenitic grain size in steels. It describes the methods of revealing grain boundaries and of estimating the mean grain size of specimens with unimodal size distribution. Although grains are three-dimensional in shape, the metallographic sectioning plane can cut through a grain at any point from a grain corner, to the maximum diameter of the grain, thus producing a range of apparent grain sizes on the two-dimensional plane, even in a sample with a perfectly consistent grain size.
Stahl - Mikrophotographische Bestimmung der erkennbaren Korngröße (ISO 643:2012)
Diese Internationale Norm legt mikrophotographische Verfahren zur Bestimmung der erkennbaren Ferrit oder Austenitkorngröße von Stählen fest. Es werden Verfahren zum Sichtbarmachen der Korngrenzen und zur Schätzung der mittleren Korngröße von Proben mit einer gleichmäßigen Größenverteilung beschrieben. Obwohl die Körner dreidimensional sind, können sie durch eine metallographische Schnittebene von einem beliebigen Punkt am Rand eines Korns bis einschließlich durch seinen maximalen Durchmesser so durchschnitten werden, dass auch in einer Probe mit vollständig übereinstimmender Korngröße in der zweidimensionalen Ebene eine erkennbare Korngröße erzeugt wird.
Aciers - Détermination micrographique de la grosseur de grain apparente (ISO 643:2012)
L'ISO 643:2012 spécifie une méthode de détermination micrographique de la grosseur apparente du grain ferritique ou austénitique des aciers. Elle décrit les méthodes de mise en évidence des joints de grains et d'estimation de la grosseur moyenne de grain d'un échantillon ayant une distribution granulométrique unimodale. Bien que les grains soient de forme tridimensionnelle, le plan de la préparation métallographique peut couper un grain en tout point, passant par un coin du grain ou au travers du diamètre maximal du grain ou entre les deux, produisant de ce fait une gamme de grosseurs de grain apparentes sur le plan bidimensionnel, même dans le cas d'un échantillon présentant une grosseur de grain parfaitement cohérente.
Jekla - Mikrografsko določevanje navidezne velikosti kristalnih zrn (ISO 643:2012)
Ta mednarodni standard podaja mikrografsko metodo za določevanje navidezne velikosti feritnih in avsteritnih kristalnih zrn v jeklu. Opisuje metode za odkrivanje mej kristalnih zrn in ocenjevanje povprečne velikosti kristalnih zrn primerkov z enomodalno razporeditvijo velikosti. Čeprav so kristalna zrna tridimenzionalne oblike, lahko plošča za metalografski prerez v kateri koli točki prereže zrno od kota zrna do največjega prereza in tako na dvodimenzionalni plošči naredi nabor navideznih velikosti kristalnih zrn. To velja tudi za vzorce, ki imajo popolnoma skladno velikost zrna.
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Standards Content (Sample)
SLOVENSKI STANDARD
01-junij-2013
1DGRPHãþD
SIST EN ISO 643:2004
-HNOD0LNURJUDIVNRGRORþHYDQMHQDYLGH]QHYHOLNRVWLNULVWDOQLK]UQ ,62
Steels - Micrographic determination of the apparent grain size (ISO 643:2012)
Stahl - Mikrophotographische Bestimmung der scheinbaren Korngröße (ISO 643:2012)
Aciers - Détermination micrographique de la grosseur de grain apparente (ISO
643:2012)
Ta slovenski standard je istoveten z: EN ISO 643:2012
ICS:
77.040.99 Druge metode za Other methods of testing of
preskušanje kovin metals
77.080.20 Jekla Steels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN ISO 643
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2012
ICS 77.040.99 Supersedes EN ISO 643:2003
English Version
Steels - Micrographic determination of the apparent grain size
(ISO 643:2012)
Aciers - Détermination micrographique de la grosseur de Stahl - Mikrophotographische Bestimmung der scheinbaren
grain apparente (ISO 643:2012) Korngröße (ISO 643:2012)
This European Standard was approved by CEN on 10 December 2012.
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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 643:2012: E
worldwide for CEN national Members.
Contents Page
Foreword . 3
Foreword
This document (EN ISO 643:2012) has been prepared by Technical Committee ISO/TC 17 "Steel" in
collaboration with Technical Committee ECISS/TC 101 “Test methods for steel (other than chemical analysis)”
the secretariat of which is held by AFNOR.
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 2013, and conflicting national standards shall be withdrawn at
the latest by June 2013.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 643:2003.
According to the CEN/CENELEC Internal Regulations, the national standards organisations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 643:2012 has been approved by CEN as a EN ISO 643:2012 without any modification.
INTERNATIONAL ISO
STANDARD 643
Third edition
2012-12-15
Steels — Micrographic determination of
the apparent grain size
Aciers — Détermination micrographique de la grosseur de grain
apparente
Reference number
ISO 643:2012(E)
©
ISO 2012
ISO 643:2012(E)
© ISO 2012
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
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Published in Switzerland
ii © ISO 2012 – All rights reserved
ISO 643:2012(E)
Contents Page
Foreword .iv
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Symbols and abbreviated terms .2
5 Principle.2
6 Selection and preparation of the specimen.4
6.1 Test location .4
6.2 Revealing ferritic grain boundaries .5
6.3 Revealing austenitic and prior-austenitic grain boundaries.5
7 Characterization of grain size .9
7.1 Characterization by an index .9
7.2 Characterization by the intercept method .11
8 Test report.14
Annex A (informative) Summary of methods for revealing ferritic, austenitic or prior-austenitic
grain boundaries in steels.15
Annex B (normative) Determination of grain size — Standard charts taken from ASTM E112.16
Annex C (normative) Evaluation method .31
ISO 643:2012(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 643 was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 7, Methods of testing
(other than mechanical tests and chemical analysis).
This third edition cancels and replaces the second edition (ISO 643:2003), of which it constitutes a minor
revision. A note was added after the first paragraph of 7.1.2.
iv © ISO 2012 – All rights reserved
INTERNATIONAL STANDARD ISO 643:2012(E)
Steels — Micrographic determination of the apparent grain size
1 Scope
This International Standard specifies a micrographic method of determining apparent ferritic or austenitic grain
size in steels. It describes the methods of revealing grain boundaries and of estimating the mean grain size of
specimens with unimodal size distribution. Although grains are three-dimensional in shape, the metallographic
sectioning plane can cut through a grain at any point from a grain corner, to the maximum diameter of the
grain, thus producing a range of apparent grain sizes on the two-dimensional plane, even in a sample with a
perfectly consistent grain size.
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 3785, Steel — Designation of test piece axes
ISO 14250, Steel — Metallographic characterization of duplex grain size and distributions
ASTM E112, Standard Test Methods for Determining Average Grain Size
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
grain
closed polygonal shape with more or less curved sides, which can be revealed on a flat cross-section through
the sample, polished and prepared for micrographic examination
A distinction is made between:
3.1.1
austenitic grain
crystal with a face-centered cubic crystal structure which may, or may not, contain annealing twins
3.1.2
ferritic grain
1)
crystal with a body-centered cubic crystal structure which never contains annealing twins
1) Ferritic grain size is generally estimated for non-alloy steels with a carbon content of 0,25 % or less. If pearlite islands
of identical dimensions to those of the ferrite grains are present, the islands are then counted as ferrite grains.
ISO 643:2012(E)
3.2
index
positive, zero or possibly negative number G which is derived from the mean number m of grains counted in
an area of 1 mm of the section of the specimen
NOTE By definition, G = 1 where m = 16; the other indices are obtained by the formula
G
m=×82
3.3
intercept
N
number of grains intercepted by a test line, either straight or curved
See Figure 1.
NOTE Straight test lines will normally end within a grain. These end segments are counted as 1/2 an interception. N
is the average of a number of counts of the number of grains intercepted by the test line applied randomly at various
locations. N is divided by the true line length, L , usually measured in millimetres, in order to obtain the number of grains
T
intercepted per unit length, N .
L
3.4
intersection
P
number of intersection points between grain boundaries and a test line, either straight or curved
See Figure 1.
NOTE P is the average of a number of counts of the number of grain boundaries intersected by the test line applied
randomly at various locations. P is divided by the true line length, L , usually measured in millimetres, in order to obtain
T
the number of grain boundary intersections per unit length, P .
L
4 Symbols and abbreviated terms
The symbols used are given in Table 1.
5 Principle
The grain size is revealed by micrographic examination of a polished section of the specimen prepared by an
appropriate method for the type of steel and for the information sought.
NOTE If the order or the International Standard defining the product does not stipulate the method of revealing the
grain, the choice of this method is left to the manufacturer.
This average size is characterized either
a) by an index obtained
⎯ usually by comparison with standard charts for the measurement of grain size;
⎯ or by counting to determine the average number of grains per unit area;
b) or by the mean value of the intercepted segment.
2 © ISO 2012 – All rights reserved
ISO 643:2012(E)
Interception, N, counts for a straight line on a single-phase grain structure where the arrows point to
6 intercepts and two line segments ending within grain (2 × 1/2 = 1 N) and N = 7
Intersection, P, counts for a straight test line placed over a single-phase grain structure where the arrows point
to 7 intersection points and P =7
Figure 1 — Examples of intersection, P, and interception, N
ISO 643:2012(E)
Table 1 — Symbols
Sym
...
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