SIST EN 10247:2007

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Micrographic examination of the non-metallic inclusion content of steels using standard picturesDétermination micrographique de la teneur en inclusions non-métalliques des aciers a l'aide d'images-typesMetallographische Prüfung des Gehaltes nichtmetallischer Einschlüsse in Stählen mit BildreihenTa slovenski standard je istoveten z:EN 10247:2007SIST EN 10247:2007en,fr,de77.040.99Druge metode za preskušanje kovinOther methods of testing of metalsICS:SIST ENV 10247:2000/AC:2001SIST ENV 10247:20001DGRPHãþDSLOVENSKI
STANDARDSIST EN 10247:200701-september-2007







EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 10247April 2007ICS 77.040.99Supersedes ENV 10247:1998
English VersionMicrographic examination of the non-metallic inclusion contentof steels using standard picturesDétermination micrographique de la teneur en inclusionsnon-métalliques des aciers à l'aide d'images-typesMetallographische Prüfung des Gehaltes nichtmetallischerEinschlüsse in Stählen mit BildreihenThis European Standard was approved by CEN on 13 January 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN 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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2007 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 10247:2007: E



EN 10247:2007 (E)
2 Contents Foreword.5 Introduction.6 1 Scope.7 2 Normative references.7 3 Principles.7 4 Terms and definitions.8 4.1 General.8 4.2 Proximity.9 4.3 Parameters.9 4.4 Classes.10 4.5 Others.10 5 Symbols and abbreviations.11 6 Sampling.13 6.1 General.13 6.2 Minimum reduction.13 6.3 Size and location of test area.13 6.4 Number of specimens.14 6.5 Preparation of specimens.14 7 Test method.14 7.1 Magnification.14 7.2 Field of view.15 7.3 Definition of the pictures of the chart.15 7.3.1 Size and Shape.15 7.3.2 Parameters.15 7.3.3 Arrangement of the pictures.15 7.4 Procedure.15 7.4.1 General.15 7.4.2 Several inclusions of mixed sizes in one field.16 7.4.3 Scanning.16 7.4.4 Assessment and evaluation.16 7.4.5 Evaluation of different types of inclusions.17 7.4.6 Default assumptions.17 7.4.7 Recording of results.17 8 Types of assessment.17 8.1 Worst inclusion method: method P.17 8.1.1 Principle.17 8.1.2 Evaluation of PL (worst length).17 8.1.3 Evaluation of Pd (worst diameter).18 8.1.4 Evaluation of Pa (worst area).18 8.2 Worst field method: method M.18 8.2.1 Principle.18 8.2.2 Evaluation of Mn (rating according to number).18 8.2.3 Evaluation of ML (rating according to length).18 8.2.4 Evaluation of Md (rating according to diameter).18 8.2.5 Evaluation of Ma (rating according to area).18 8.3 Average field method: method K.19



EN 10247:2007 (E) 3 8.3.1 Principle.19 8.3.2 Scanning of a specimen for average field assessment.19 8.3.3 Evaluation.20 8.3.4 Evaluation of Kn, KL for elongated and Kn, Kd for globular inclusions.20 8.3.5 Evaluation of Kn and Ka.20 9 Test report.21 Annex A (normative)
Type of inclusions.34 Annex B (normative)
Parameters and assessments to be used if not otherwise specified.36 Annex C (informative)
Examples for inclusions of different types.37 Annex D (informative)
Shape factor.41 Annex E (informative)
Examples for magnification.42 Annex F (informative)
Details of the eyepiece graticules.44 Annex G (normative)
Manufacturing of eyepiece graticule.45 G.1 General.45 G.2 Narrow field microscopes.45 G.3 Broad field microscopes.46 Annex H (normative)
Calculation basis for the pictures of the chart.49 Annex K (normative)
Rules for classification.51 K.1 Definition of classes.51 K.2 Classification of length.51 K.3 Classification of width.51 K.4 Classification of diameter.51 K.5 Classification of area.52 Annex L (informative)
Comparison of inclusion types in different standards.53 Annex M (informative)
Worst inclusion assessment.54 Annex N (informative)
Worst field assessment.56 N.1 General.56 N.2 Evaluation of Mn.56 N.3 Evaluation of Mn, ML and Md.56 N.4 Evaluation of Mn and Ma.57 Annex P (informative)
Average field assessment.60 P.1 General.60 P.2 Evaluation of Kn, KL and Kd.60 P.3 Evaluation of Kn and Ka.60 P.4 Restricted values.60 Annex Q (normative)
Calculation basis for the assessment.69 Q.1 Worst inclusion assessment.69 Q.2 Worst field assessment.69 Q.2.1 Calculation of Mn.69 Q.2.2 Calculation of ML.69 Q.2.3 Calculation of Md.70 Q.2.4 Calculation of Ma.70 Q.3 Average field.70 Annex R (normative)
Determination of precision and scanning parameters for average field assessment.72 Annex S (informative)
Edge Errors correction.75 S.1 General.75 S.2 Field by field measurement.75 Annex T (normative)
Calculation of average values of parameters for one class.77



EN 10247:2007 (E)
4 Annex U (normative)
Average values of parameters.79 Annex V (informative)
Comments of the working group.80 V.1 General.80 V.2 Length.80 V.3 Width.80 V.4 Number.80 V.5 Resolution.80 V.6 Area.81 V.7 Description of inclusions.81 V.8 Globular particles.82 V.9 Shape factor.82 V.10 Combined inclusions.83 V.11 Measuring frame.83 Bibliography.84



EN 10247:2007 (E) 5 Foreword This document (EN 10247:2007) has been prepared by Technical Committee ECISS/TC 2 “Steel - Physico-chemical and non-destructive testing”, 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 October 2007, and conflicting national standards shall be withdrawn at the latest by October 2007. 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 ENV 10247:1998. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.



EN 10247:2007 (E)
6 Introduction This document establishes procedures for the assessment of inclusions in steels, based on their morphology using standard pictures. These procedures include principles that are coherent with physical results obtained from inclusion measurements. The results are in physical units: length in µm/ mm2, number/ mm2, areas in µm2/ mm2. In comparison to other inclusion rating standards, in this standard the order of the classification begins with the length (row index q).These results can be transposed into other standard's ratings for comparison purposes. The conditions of assessments, for instance the rules to scan fields on the specimen, are defined such that there is an optimization between magnification and the number of fields to be assessed. The same precision level is achieved by using the same method in manual evaluation and computer controlled measurements. The chart of standard pictures is derived from mathematical principles. The results and their precision may be directly computed from field assessments.



EN 10247:2007 (E) 7 1 Scope This European Standard defines a method of microscopic non-metallic inclusion assessment using picture charts. The method does not apply to particles of a length less than 3,0 µm or a width smaller than 2,0 µm. Defined by a product standard or agreement between the involved parties for certain special products, inclusions with a width below 2,0 µm can only be evaluated according to their length. Elongated inclusions with a length above 1 410 µm are counted separately and are beyond the upper application limit of this standard. Globular inclusions with a diameter of 3,0 µm and above are included in the assessment. It is assumed, if particles are elongated or if there are stringers of particles, that they are parallel to each other. Other arrangements are not covered by this standard. This European Standard applies to samples with a microscopic precipitation approaching random distribution. From the data of measurements obtained by this method, evaluation according to other standards can be established. This European Standard does not apply to free cutting steels. NOTE The basic principle of this European Standard allows the determination of non-metallic inclusion content by image analysis techniques. 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. EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:2005) 3 Principles This method consists of a comparison between inclusions observed in a field of view with chart pictures. The chart pictures defined by this European Standard are based on the shape of inclusions and for each shape on length, width and area, for columns 1 to 10 and number for column 11. This standard employs an ellipse as a basic shape with the circle as a special case of an ellipse (see Figure 1a). Inclusions with a shape like a rectangle or square are treated as ellipses or circles as their areas are not significantly different for the purpose of this method. The pictures are arranged in rows and columns. The length changes from row to row, the shape factor changes from column to column. This standard is principally concerned with the morphology and arrangement of inclusions. It does not provide information relevant to crystal structure or chemical constitution of measured inclusions. General practice usually requires a differentiation between inclusions of different chemical composition. The definition of the types should be defined by the product standards. Should no standard be available, then the definition of characteristic morphologies shall be, by agreement, between the involved parties. To make description easier, a tree of specific terms is given in Annex A, Figure A.1. The chart pictures represent the upper limits of classes. The length Lx is classified in row q if: qx1-q
LLL≤<µm (1)



EN 10247:2007 (E)
8 The width wx is classified in column k if: kx1-k
www≤< µm (2) In Figure 5 the first row on the top without number and the first column on the left without number and a thicker surrounding contain the lower limiting pictures. Inclusions with a length shorter than that given in that row or a width smaller than that given in that column are not taken into account for classification. Inclusions classified as columns 6 and 11 are called globular. The parameters measured are number, length, width and area. The results of the evaluations can give expressions of worst inclusion, worst field or an average field value, all of which have physical dimensions. In addition to these values, this method gives an estimation of distribution of the inclusions within the test specimens. The entire chart is mathematically based. It has a limited number of pictures, which limits choice and hence improves reproducibility when used in a manual method. The mathematical basis permits use by manual and image analysis methods providing potential for higher statistical precision. The data produced gives a wide range of features for cleanness definition. The chart employs different shapes and magnifications allowing an application to cleaner steels where shape control is of interest. This European Standard contains several different methods of evaluation. The choice of method shall be defined by the product standard or be agreed between the involved parties. By default, the methods of evaluation used are the worst inclusion and the average field method; parameters are given in Annex B. The methods PL, Pd; Kn, KL and Kn, Kd are proposed as standard methods. 4 Terms and definitions For the purposes of this document, the following terms and definitions apply. 4.1 General 4.1.1 particle single precipitate, in general non-metallic 4.1.2 inclusion general designation of particles in association, defined by the size and proximity of particles. It describes a single, separated particle as well as an arrangement of at least 2 particles (see Figure 2a) if the distance t
is ≤ 10 µm and the distance e is ≤ 40 µm and the main axis of the particles are parallel within ± 10 °. For an arrangement of only two globular particles, each particle shall be considered as an individual inclusion. An inclusion can also be formed by several stringers if the distances t and e are ≤ 10 µm and ≤ 40 µm (see Figure 2b). Particles with L < 3 µm or w < 2 µm are not taken into account (see Figure 2c). Special cases: If elongated and more or less spherical particles are combined, see Figure 2d, in general it is treated as one inclusion. In case 4 the width of the largest particle is consulted for the width of the inclusion. If in this case w1 > 3 w2 then the particles w1 and w2 are treated separately. For an example see Figure 2e. Some examples for inclusions are given in Figure 2f



EN 10247:2007 (E) 9 4.1.3 stringer arrangement of at least 3 particles, normally aligned, forming an inclusion (see Figures 2b, 2f), For examples see Annex C and Figure 2f 4.1.4 test area area on the polished surface of the specimen to be evaluated NOTE In general, the size of the test area is 200 mm2. 4.2 Proximity 4.2.1 distances between particles distance e between the particles in the direction of main deformation and distance t in the direction perpendicular to it (see Figure 2a) 4.2.2 distance between stringers similar to that for the distance between particles (see Figure 2b) 4.2.3 scattered random arrangement of particles.
NOTE For example see Annex C. This is defined in one field of view 4.3 Parameters 4.3.1 length dimension of an inclusion in the main direction of deformation, always assumed to be greater than the width 4.3.2 diameter maximum dimension of inclusion classified according to column 6 (globular inclusion) 4.3.3 width Maximum width perpendicular to the direction of principal deformation. This is the width of the ellipse inscribed to the confining rectangle and having the same length as the inclusion. For manual evaluation this value can only be estimated. The width is the maximum width perpendicular to the direction of principal deformation for inclusions with only one particle. The width w of an inclusion with 2 particles is given by the largest particle (see Figure 2a). Width of a stringer (see Figure 1b): The width of a stringer is defined as the width of an ellipse inscribed to the confining rectangle and having the same length as the stringer Width of an inclusion out of several stringers (see Figure 2b). The distance t between two stringers is defined as the shortest distance between the confining rectangles in a transverse direction. The distance e is defined as the shortest distance between the confining rectangles in a machine direction. Case a) for 0 ≤ e ≤ 40 µm, t ≤ 10 µm: is the width of an inclusion out of two stringers defined as the width of the widest stringer. (wtotal = w1, w1 > w2) (see Figure 2b, a)).



EN 10247:2007 (E)
10 Case b) for e < 0 µm, t ≤ 10 µm: is the width of an inclusion out of two stringers defined as the sum of the stringers' widths and the distance t (wtotal = w1 + w2 + t) (see Figure 2b, b). The width of an inclusion, which consists of several stringers, is determined by the width of the widest stringer. This is identified under consideration of the neighboring stringers corresponding to case a) and b), see Figure 2b, c) 4.3.4 area area of the ellipse inscribed to the confining rectangle and having the same length as the inclusion (see 4.3.3 and Figures 1a, 1b) 4.3.5 shape factor exponent f in the equation  cL
=aL2f4 (3) NOTE For details see Annex D 4.4 Classes 4.4.1 elongated particles particles with elliptical shape (see Figure 1a) 4.4.2 globular particles circular or rectangular particles classified as column 6 4.4.3 type types of inclusions are separated according to their colour, shape and arrangement and not by chemical composition (see Annex A).
4.5 Others 4.5.1 lot unit of material processed at one time and subject to similar processing variables 4.5.2 rest
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