1、May 2013 Translation by DIN-Sprachendienst.English price group 16No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 77
2、.040.99!%#q“2008878www.din.deDDIN EN ISO 643Steels Micrographic determination of the apparent grain size (ISO 643:2012);English version EN ISO 643:2012,English translation of DIN EN ISO 643:2013-05Stahl Mikrophotographische Bestimmung der erkennbaren Korngre (ISO 643:2012);Englische Fassung EN ISO 6
3、43:2012,Englische bersetzung von DIN EN ISO 643:2013-05Aciers Dtermination micrographique de la grosseur de grain apparente (ISO 643:2012);Version anglaise EN ISO 643:2012,Traduction anglaise de DIN EN ISO 643:2013-05SupersedesDIN EN ISO 643:2003-09 andDIN EN ISO 643 www.beuth.deDocument comprises p
4、agesIn case of doubt, the German-language original shall be considered authoritative.Corrigendum 1:2004-074005.13 DIN EN ISO 643:2013-05 2 A comma is used as the decimal marker. National foreword This document (EN ISO 643:2012) has been prepared by Technical Committee ISO/TC 17 “Steel” in collaborat
5、ion with Technical Committee ECISS/TC 101 “Test methods for steel (other than chemical analysis)” (Secretariat: AFNOR, France). The responsible German body involved in its preparation was the Normenausschuss Materialprfung (Materials Testing Standards Committee), Working Committee NA 062-01-31 GA Ge
6、meinschaftsarbeits-ausschuss NMP/FES: Metallographische Prfverfahren. Users of this standard should note the following: Although footnote 4 states that the standard charts in Annex B have been taken from ASTM E 112, not all the charts are equivalent to those in ASTM E 112. The test circles in these
7、charts, which are for determining grain sizes from 00 to 10, have different diameters, and all of these diameters differ from those in the charts of ASTM E 112. This means that a correct determination of grain size cannot be ensured when a manual method is used on the basis of the charts in this doc
8、ument. Therefore, we strongly urge users of this standard to use the original charts in ASTM E 112 when evaluating grain size by means of manual analysis. The DIN Standard corresponding to the International Standard referred to in this document is as follows: ISO 3785 DIN EN ISO 3785 Amendments This
9、 standard differs from DIN EN ISO 643:2003-09 and DIN EN ISO 643 Corrigendum 1:2004-07 as follows: a) in Subclause 7.1.2, a NOTE has been added concerning the magnification of the standard charts in Annex B; b) the title of the German version has been changed to read Stahl Mikrophotographische Besti
10、mmung der erkennbaren Korngre; c) the standard has been editorially revised. Previous editions DIN 50601: 1985-08 DIN EN ISO 643: 2003-09 DIN EN ISO 643 Corrigendum 1: 2004-07 National Annex NA (informative) Bibliography DIN EN ISO 3785, Metallic materials Designation of test specimen axes in relati
11、on to product texture EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 643 December 2012 ICS 77.040.99 Supersedes EN ISO 643:2003English Version Steels - Micrographic determination of the apparent grain size (ISO 643:2012) Aciers - Dtermination micrographique de la grosseur de grain apparent
12、e (ISO 643:2012) Stahl - Mikrophotographische Bestimmung der erkennbaren Korngre (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 t
13、he 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, Fre
14、nch, 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
15、, 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
16、 and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO
17、 643:2012: EContents DIN EN ISO 643:2013-05 EN ISO 643:2012 (E) 2 Page Foreword . . 1 Scope2 Normative references4 3 Terms and definitions .4 4 Symbols and abbreviated terms 5 5 Principle 6 Selection and preparation of the specimen7 6.1 Test location 7 6.2 Revealing ferritic grain boundaries .8 6.3
18、Revealing austenitic and prior-austenitic grain boundaries.7 Characterization of grain size 7.1 Characterization by an index .12 7.2 Characterization by the intercept method 14 8 Test report1Annex A (informative) Summary of methods for revealing ferritic, austenitic or prior-austenitic grain boundar
19、ies in steels18 Annex B (normative) Determination of grain size Standard charts taken from ASTM E11219 Annex C (normative) Evaluation method .3 712 8 54 3.4Foreword This document (EN ISO 643:2012) has been prepared by Technical Committee ISO/TC 17 Steel” in collaboration with Technical Committee ECI
20、SS/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 sta
21、ndards 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
22、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, F
23、rance, 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
24、ISO 643:2012 without any modification. “DIN EN ISO 643:2013-05 EN ISO 643:2012 (E) 3 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 m
25、ean 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-d
26、imensional 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 referen
27、ced 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
28、 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 wi
29、th a face-centered cubic crystal structure which may, or may not, contain annealing twins 3.1.2 ferritic grain crystal with a body-centered cubic crystal structure which never contains annealing twins1)1) Ferritic grain size is generally estimated for non-alloy steels with a carbon content of 0,25 %
30、 or less. If pearlite islands of identical dimensions to those of the ferrite grains are present, the islands are then counted as ferrite grains. DIN EN ISO 643:2013-05 EN ISO 643:2012 (E) 4 3.2 index positive, zero or possibly negative number G which is derived from the mean number m of grains coun
31、ted in an area of 1 mm2of the section of the specimen NOTE By definition, G = 1 where m = 16; the other indices are obtained by the formula 82Gm = 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
32、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, T,L usually measured in millimetres, in order to obtain the number of
33、 grains intercepted per unit length, .LN 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 v
34、arious locations. P is divided by the true line length, T,L usually measured in millimetres, in order to obtain the number of grain boundary intersections per unit length, .LP 4 Symbols and abbreviated terms The symbols used are given in Table 1. 5 Principle The grain size is revealed by micrographi
35、c 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
36、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. DIN EN ISO 643
37、:2013-05 EN ISO 643:2012 (E) 5 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 stru
38、cture where the arrows point to 7 intersection points and P =7 Figure 1 Examples of intersection, P, and interception, N DIN EN ISO 643:2013-05 EN ISO 643:2012 (E) 6 Table 1 Symbols Symbols Definition Value a Mean area of grain in square millimetres 1am= AFApparent area of the test figure in square
39、millimetres d Mean grain diameter in millimetres 1dm= D Diameter of the circle on the ground glass screen of the microscope or on a photomicrograph enclosing the image of the reference surface of the test piece 79,8 mm (area = 5 000 mm2) g Linear magnification (to be noted as a reference) of the mic
40、roscopic image In principle 100 G Equivalent index of grain size K Conversion factor from linear magnification g to linear magnification 100 100gK = l Mean lineal intercept length, generally expressed in millimetres 1/ 1/ LLlN P= LTTrue length of the test line divided by the magnification, in millim
41、etres m Number of grains per square millimetre of test piece surface in the area examined m = 2 n100(magnification 100) m = 2 K2ng(magnification g) M Number of the closest standard chart picture where g is not 100. ngTotal equivalent number of grains examined on the image of diameter D (with a magni
42、fication g) n1Number of grains completely inside the circle of diameter D n2Number of grains intersected by the circle of diameter D n100Total equivalent number of grains examined on the image of diameter D (with magnification 100) 2100 12nnn=+ N Mean number of grains intercepted per unit length L L
43、N Mean number of grains intercepted per unit length of the line T/LNNL= NxNumber of intercepts per millimetre in the longitudinal direction a NyNumber of intercepts per millimetre in the transverse direction a NzNumber of intercepts per millimetre in the perpendicular direction a P Mean number of co
44、unts of the number of grain boundaries intersected by the test line applied randomly at various locations LP Mean number of grain boundary intersections per unit length of test line T/LP PL= aThe method for designating the direction conforms to ISO 3785. 6 Selection and preparation of the specimen 6
45、.1 Test location If the order, or the International Standard defining the product, does not specify the number of specimens and the point at which they are to be taken from the product, these are left to the manufacturer, although it has DIN EN ISO 643:2013-05 EN ISO 643:2012 (E) 7 been shown that p
46、recision of grain size determination increases the higher the number of specimens assessed. Therefore, it is recommended that two or more sections be assessed. Care shall be taken to ensure that the specimens are representative of the bulk of the product (i.e., avoid heavily deformed material such a
47、s that found at the extreme end of certain products or where shearing has been used to remove the specimen etc.). The specimens shall be polished in accordance with the usual methods. Unless otherwise stated by the product standard or by agreement with the customer, the polished face of the specimen
48、 shall be longitudinal, i.e., parallel to the principal axis of deformation in wrought products. Measurements of the grain size on a transverse plane will be biased if the grain shape is not equiaxial. 6.2 Revealing ferritic grain boundaries The ferritic grains shall be revealed by etching with nita
49、l (ethanolic 2 % to 3 % nitric acid solution), or with an appropriate reagent. 6.3 Revealing austenitic and prior-austenitic grain boundaries 6.3.1 General In the case of steels having a single-phase or two-phase austenitic structure (delta ferrite grains in an austenitic matrix) at ambient temperature, the grain shall be revealed by an etching solution. For single phase austenitic stainless steels, the most commonly used chemical etchants are glyceregia, Kallings reagent (No. 2) and Marbles reagent. The be
