1、BSI BS*EN*ISO 2624 95 Lb24669 0474854 9T8 BRITISH STANDARD Copper and copper alloys - Estimation of average grain size The European Standard EN IS0 2624 : 1995 has the status of a British Standard BS EN IS0 2624 : 1995 BS EN IS0 2624 : 1995 under the authority of the Standards Board and comes into e
2、ffect on 15 September 1995 BSI 1995 Amd. No. The following BSI references relate to the work on this standard: Committee reference NFE/34 Draft for comment 90/37770 DC ISBN O 580 24476 8 Committees responsible for this British Standard Date Text affected The preparation of this British Standard was
3、entrusted to Technical Committee NFE/34, Copper and copper alloys, upon which the following bodies were represented: British Bathroom Council British Cable Makers Confederation British Non-ferrous Metals Federation British Refrigeration Association British Valve and Actuator Manufacturers Associatio
4、n Copper Development Association London Metal Exchange Non-ferrous Metal Stockists Transmission and Distribution Association (BEAMA Limited) Coopted members The following bodies were also represented in the drafting of the standard, through subcommittees and panels: British Plumbing Fittings Manufac
5、turers Association British Railways Board British Turned-parts Manufacturers Association Institution of Incorporated Executive Engineers London Regional Transport National Association of Plumbing, Heating and Mechanical Services Power Generation Contractors Association (PGCA) (BEAMA Ltd.) Spring Res
6、earch and Manufacturers Association Contractors BSI BS*EN*ISO 2624 95 1624669 0474856 770 BS EN IS0 2624 : 1995 Contents Committees responsible National foreword Page Inside front cover 11 Foreword 2 Introduction Specification 1 Scope 2 Symbols and designations 3 3 Test samples 3 4 Procedures 3 5 Te
7、st report 4 Annex A Standard grain size charts x 75) 5 lbles 1 Jeffries multipliers for area of 5000 mm2 4 2 Relationships between the actual grain size of specimens viewed at various magnifications and the standard series of photomicrographs 4 1 BSI BS*EN*ISO 2624 95 lb24bb 0494857 bo7 BS EN IS0 26
8、24 : 1996 National foreword This British Standard has been prepared by Technical Committee NFE/34 and is the English language version of EN Is0 2624 : 1995 Copper and copper alloys - Estimation of average grain size, published by the European Committee for Standardization (CEN). It supersedes BS 742
9、8 : 1991 which is withdrawn. EN IS0 2624 : 1995 is identical with IS0 2624 : 1990, published by the International Organization for Standardization (ISO). It was produced as a result of international discussions in which the United Kingdom took an active part. The standard grain size charts in normat
10、ive annex A are reproduced with permission from the annual book of ASTM Standards (Copyright ASTM). Compliance with a British Standard does not of itself confer immunity from legal obligations. ii BSI BS*EN*ISO 2624 95 1624669 0494858 543 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN IS0 2624
11、 May 1995 ICs 77.040.30 Descriptorj: copper, copper alloys, grain size analysis, microstructure, grain structure, microscopy, microphotography English version Copper and copper alloys - Estimation of average grain size (IS0 2624 : 1990) Cuivre et alliages de cuivre - Evaluation de la dimension moyen
12、ne du grain (IS0 2624 : 1990) Kupfer- und Kupferlegierungen - Bestimmen der mittleren KorngrBe (IS0 2624 : 1990) This European Standard was approved by CEN on 1995-02-26. CEN members are bound to comply with the CENXENELEC Internal Regulations which stipulate the conditions for giving this European
13、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 Central Secretariat or to any GEN member. L This European Standard exists in three official versions (English, F
14、rench, 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 Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland
15、, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Bruss
16、els O 1995 All rights of reproduction and communication in any form and by any means reserved in all countries to CEN and its members Ref. No. EN IS0 2624 : 1995 E BSI BS*EN*ISO 2b24 95 Lb24bb9 0474857 48T E Page 2 EN IS0 2624 : 1995 Foreword The text of the International Standard from ISO/X 26, Cop
17、per and copper alloys, of the International Organization for Standardization (ISO) has been taken over as a European Standard by CEN/X 133, Copper and copper alloys. The European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement,
18、at the latest by November 1995, and conflicting national standards shall be withdrawn at the latest by November 1995. According to the CENKENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece,
19、Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom. Introduction On a section of metal, a grain is that area within the boundary of a crystal. For the purpose of applying the methods described in this International Standard, a crystal and i
20、ts twin bands are considered as one grain. Sub-grains, minor constituent phases, inclusions and additives are not considered in the estimation of the grain size. It is important, in using these methods, to recognize that the estimation of grain size is not a precise measurement, A metal structure is
21、 an aggregate of three-dimensional crystals of varying sizes and shapes. Even if all these crystals were identical in size and shape, the grain cross-sections produced by a random plane (surface of observation) through such a structure would have a distribution of areas varying from a maximum value
22、to zero, depending upon where the plane cuts each individual crystal. Clearly, no two fields of observation can be exactly the same. Practical reasons limit the number of grains that can reasonably be counted to less than the number statistically desirable. BSI BS*EN*ISO 2624 75 Lb24bb 0494860 LTL O
23、 Symbol f 111 d I Y Page 3 EN IS0 2624 : 1995 Designation Jeffries multiplier used to obtain number of grains per square millimetre by planimetric method Number of grains per square millimetre Average grain “diameter“ in millimetres; an arbitrary measure defined as 1 /fi Average intercept length Mag
24、nification Copper and copper alloys - Estimation of average grain size 1 Scope Thi International Standard specifies three procedures for estimating, and niles for expressing, the average grain size of copper and copper alloys consisting principally of a single phase. The respective procedures are te
25、rmed the comparison procedure, the intercept procedure and the planimetric pro- cedure. The comparison procedure (comparing the specimen with a standard chart) is most convenient and is sufficiently accurate for most commercial purposes. Higher degreees of accuracy in estimating grain size are ob- t
26、ainable by using the intercept (Heyn) or planimetric (Jeffries) procedures. In cases of dispute, it is recommended that the use of one of these procedures be agreed between the parties. For material with non-equiaxial structures it is recommended that the intercept procedure be used. 2 Symbols and d
27、esignations 3 Test samples 3.1 Grain size estimations shall be made on three or more representative fields of each sample section. In known equiaxial structures only a representative section need be taken on the sample. For non-equiaxial or unknown structures three sec- tions must be prepared, each
28、at right angles to the other. 3.2 The specimen shall be carefully prepared to reveal the grain boundaries using a contrast etch to match the standard charts. 4 Procedures 4.1 Comparison procedure The estimation of grain size is made by direct comparison of a projected image of a photomicrograph of a
29、 representative field of the test specimen, either with the photomicrographs of the standard grain size series or with suitable reproductions of them (for standard grain size charts, see annex A); when a pro- jection microscope is not available a bench microscope may be used. It is recommended that,
30、 to facilitate comparison, mechanical arrangements be made to permit bringing the stan- dard photomicrographs successively into juxtaposition with the projected image. 4.2 Intercept procedure 4.2.1 The grain size is estimated by counting, on the ground glass screen of a projection microscope, on the
31、 image in a bench microscope fitted with a graticule, on a photo- micrograph of a representative field of the specimen, or on the specimen itself, the number of grains intercepted by one or more straight lines sufficiently long to yield at least 10 inter- cepts per line and at least 50 intercepts fo
32、r all lines for normal purposes and at least 200 intercepts for referee purposes. Grains touched by the end of the line count only as half grains. The length of the line or lines in millimetres at the surface of the section, divided by the number of grains intersected by it, gives the average interc
33、ept length 1. For practical purposes, the ave- rage intercept length, I, may be regarded as equal to the ave- rage grain diameter dit. 4.2.2 For non-equiaxial structures, measurements should be made on longitudinal and transverse sections along lines that lie in all three principal directions of the
34、 specimen. For each direc- tion, the average grain “diameters“ should be calculated as in 4.2.1. 1) multiplied by the factor 1.13. To achieve compatibility with estimations of grain “diameter“ made by the planimetric or comparison procedure, the Intercept length, 1, should be BSI BS*EN*ISO 2624 75 L
35、b24bb9 04948b3 038 Image magnification x 75 (standard I x 25 x50 x loo x 200 x500 Page 4 EN IS0 2624 : 1995 Grain size when image matches standard chart rnrn 0,010 0,015 0,020 0,025 0,035 0,045 0,050 0,060 0,070 0.090 0,120 0,150 0,200 0.030 0,045 0.060 0,080 0,110 0.140 0,150 0,180 0,210 0,270 0,36
36、0 0,450 0,600 0,015 0,020 0,030 0,040 0,050 0,070 0,080 0.090 0.100 0,140 0,180 0,220 0,300 0.008 0,010 0,015 0,020 0,025 0,035 0,040 0,045 0.050 0,070 0,090 0,110 0,150 - 0,005 0,007 0,010 0,012 0,017 0.020 0.022 0,025 0,035 0,045 0,055 0,075 - - - - 0,005 0,007 0.008 0.009 0,010 0,014 0,018 0,022
37、0,030 4.3 Planimetric procedure 4.3.1 In the planimetric procedure, a circle or rectangle of known area (usually 5 o00 mm2 to simplify the calculation) is inscribed on a photomicrograph or on the ground glass screen of the projection microscope. A magnification should be selected which will give at
38、least 50 grains for normal purposes and 200 grains for referee purposes in the field to be counted. When the image is focused properly, the number of grains within this area should be counted. The sum of all the grains included completely within the known area plus one half the number of grains inte
39、rsected by the circumference of the area should be taken as giving the number of equivalent whole grains, measured at the magnifi- cation used, within the area. If this number is multiplied by Jeffries multiplier, f, in the second column of table 1 opposite the appropriate magnification, the product
40、 will be the number of grains per square millimetre, m. 4.3.2 The average grain “diameter“ in millimetres, d, for each field may then be calculated from the formula d = 1/6 Table 1 - Jeffries multipliers for area of 5 o00 mm2 Jeffries multiplier, J, to obtain grains per mm2 Magnification used, y 1 1
41、0 25 50 75.1 100 150 200 250 300 500 750 loo0 O.oo0 2 0.02 0,125 03 1,125 2,o 4.5 8.0 12.5 18,O %,O 112,5 200,o , *I At 75 diameters magnification, Jeffries multiplier, f, becomes unity if the area used is 5 625 rnm2 (a circle of 84.5 mm diameter). 5 Test report 5.1 Comparison procedure The estimate
42、d grain size for each field shall be reported as that of the nearest standard grain size chart (see annex A). Alterna- tively, where a single figure is required the median of these results shall be reported. The charts are reproduced at a magnification of x 75, which is normally suitable for copper
43、and copper alloys. If it is necessary to use other magnifications, the appropriate grain size from table 2 shall be reported. The values shown in this table have been rounded off to approximate commercial usage. Table 2 may be used for comparisons at other magnifications by using the appropriate fac
44、tor; for example, at x 250 divide by 10 the grain size indicated at x 25, or at x 400 divide by 2 the grain size indicated at x 200. Thus at x 250, a grain size which will match the same standard photograph of 0,050 rnm at x 75 will be a 0,015 mm grain size (0,150 at x 25 divided by 10). It should b
45、e appreciated that it is not uncommon for operators to differ by one step in the charts when estimating the grain size of a given field. 5.2 Intercept or planimetric procedures In equiaxial material, the results for each of the three or more representative fields on which estimations have been made
46、shall be reported. Alternatively, where a single figure is.required the median of these results shall be reported. In non-equiaxial material, when the intercept procedure should be used, the results for each of the three directions shall be reported either for individual fields or as the correspondi
47、ng me- dian for each direction. 5.3 Mixed grain sizes These are sometimes encountered, for example in hotworked metal. These shall be expressed by giving the estimated area percentages occupied by the two sizes or the two ranges of sizes, by using the comparison method. Table 2 - Relationships betwe
48、en the actual grain size of specimens viewed at various magnifications and the standard series of photomicrographs BSI BS*EN*ISO 2624 95 Lb24669 0494862 T4 Page 5 EN IS0 2624 : 1995 Annex A (normative) Standard grain size charts (X 75) NOTE - The reference photomicrograph plates given in this annex
49、are taken from the ASTM standard El 12-85, Standard methods for determjnlng the average grain size, Plate III. BSI BS*EN*ISO 2624 95 1624667 0494863 900 Page 6 EN IS0 2624 : 1995 BSI BS*EN*ISO 2624 95 1624669 0494864 847 II Page 7 EN IS0 2624 : 1995 *-s.* - 0,120 mm average grain diameter grain diameter grain diameter grain diameter BSI BS*EN*ISO 2624 95 I 1624667 0494865 783 = Page 8 EN IS0 2624 : 1995 grain diameter grain diameter grain diameter grain diameter BSI BS*EN*ISO 2624 95 Lb24bb 04948bb bLT I Page 9 EN IS0 2624 : 1995 I grain di
