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1、 G 0552 :1998 Foreword This translation has been made based on the original Japanese Industrial Standard revised by the Minister of International Trade and Industry through deliberations at Japanese Industrial Standards Committee in accordance with the Industrial Standardization Law. Consequently JI
2、S G 05521977 is replaced with JIS G 0552:1998. Date of Establishment: 1957-09-18 Date of Revision: 1998-02-20 Date of Public Notice in Official Gazette: 1998-02-20 Investigated by: Japanese Industrial Standards Committee Divisional Council on Iron and Steel JIS G 0552:1998, First English edition pub
3、lished in 1998-06 Translated and published by: Japanese Standards Association 4-1-24, Akasaka, Minato-ku, Tokyo, 107-8440 JAPAN In the event of any doubts arising as to the contents, the original JIS is to be the final authority. O JSA 1998 All rights reserved. Unless otherwise specified, no part of
4、 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 the publisher. Printed in Japan PROTECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under licens
5、e with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/26/2007 01:05:16 MDTNo reproduction or networking permitted without license from IHS -,-,- JAPANESE INDUSTRIAL STANDARD JIS G 0552 : 1998 Methods of ferrite grain determination test for steel Introduction This Japanese
6、 Industrial Standard was partially revised in 1977 since establishment in 1957, and has come to present. Though nearly 20 years have elapsed from the last revision, since there is a necessity for achieving conformance to International Standard IS0 643: 1983, Steels - Micrographic determination of th
7、e ferritic or austenitic grain size cojointly with technical progress during that time, the revision is executed. Main revised points are as follows. a) b) c) The application range is conformed to 0.25 % or under carbon content. The use symbol and the relation formula are conformed to International
8、Standard. Further, the item of report is newly established. As the judging method, a counting method and a judging method by intersected segment (grain size) are added as Annexes. 1 Scope This Japanese Industrial Standard specifies the testing method of measuring ferrite grain size (hereafter referr
9、ed to as “grain size“) of steel mainly with a carbon content not more than 0.25 %. Remarks: The corresponding International Standard to this Standard is shown as follows. IS0 643 Steels - Micrographic determination of the ferritic or austenitic grain size 2 Definitions For the purpose of this Standa
10、rd, the following definitions apply: a) grain size Grain size means the size of ferrite crystal grain of steel, and its marking is expressed in grain size number. b) grain size number The grain size number means the number expressed in accordance with either the method 1) or 2) undermentioned after
11、the grain size has been measured by the specified method. 1) Table 1 shall apply to the expression of grain size number when the measurement is made by comparison method. PROTECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111
12、111001, User=Wing, Bernie Not for Resale, 03/26/2007 01:05:16 MDTNo reproduction or networking permitted without license from IHS -,-,- 2 G 0552 : 1998 Grain size No. G -3 -2 -1 O 1 2 3 4 5 6 7 8 9 10 Table 1 Grain size number Number of crystal grain per mmz of sectional area m 1 2 4 8 16 32 64 128
13、256 512 1 024 2048 40% 8 192 Mean sectional area if crystal grain mm2 1 0.5 0.25 0.125 0.062 5 0.031 2 0.015 6 0.007 81 0.003 90 0.001 95 O.OO0 98 O.Oo0 49 o.OO0 244 o.oO0 122 Mean number of crystal grain in 25 mmz at 100 magnifications n 0.062 5 0.125 0.25 0 . 5 1 2 4 8 16 32 64 128 256 512 Remarks
14、: In Table 1, the following relation formula is concluded. r n = 8 2 2) In measurements made by intercept method, the following formula shall apply to the expression of grain size number. The grain size number shall be rounded off to the first decimal place. n=500(Ml 100)2(IxI)l(LxL2) G=(log n)l(0.3
15、01)+1 . (1) where, G : grain size No. n : number of grain size in 25 mm2 under a microscope of 100 magnification M : microscope magnification L(or Lz) : total length (unit: mm) of one linear length of the Il (or Z2) : total number of crystal grain intercepted by L i (or segments orthogonally crossin
16、g each other Remarks: Attached Fig. 3 shows a relationship included within formula (1) in a graphic chart. c) mixed grain Mixed grain shall mean the presence of 20 percent or more of crystal grain different, approximately 3 or more in grain size number within one visual field. elongation rate This i
17、s the ferrite crystal grain elongated due to the working, which shall be calculated from the following formula: d) PROTECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/26/2007 01:
18、05:16 MDTNo reproduction or networking permitted without license from IHS -,-,- 3 G 0552 : 1998 where, e : elongation rate ni : number of crystal grain intercepted by a certain length of a segment orthogonal to the direction in which the grains have been elongated n2 : number of crystal grain interc
19、epted by a segment identical in length to the ni segment parallel to the direction in which the grains have been elongated 3 following two categories: Classification of testing methods Testing methods shall be classified into a) Comparison method b) Intercept method The test shall be made, usually,
20、by comparison method, but, where ferrite crystal grains are markedly elongated or required to be accurate, intercept method should be rather used. Further, the counting method may be used as agreed upon between the purchaser and supplier. In this case Annex 1 applies. Also, the intersected segment m
21、ethod may be used as agreed upon between the purchaser and supplier. In this case, Annex 2 applies. 4 Steel with the section parallel to or at a right angle to the working direction shall be etched after being finished by polishing. For this etching, a solution, preferably of about 5 percent nitric
22、acid alcohol should be applied for 15 s. If necessary, the surface, as it is, of the test piece may be subjected to the testing. Treatment of test piece Remarks: As the etching solution nitryl (ethanol nitrate), picryl (ethanol picrate) or an appropriate reagent may be used excepting this. 5 Testing
23、 methods 5.1 be observed under a microscope and compared with a standard figure. Comparison method The grain sizes as appearing on the etched surface shall 5.2 Intercept method The number of the ferrite crystal grain intercepted by the 2 segments of a fixed length orthogonally crossing each other sh
24、all be determined by observing the grains appearing on the etched plane under a microscope or by means of a microphotograph. However, the ferrite crystal grain partially intercepted at both ends of a segment shall be counted only one grain and in case there is one partially intercepted grain at one
25、end of a segment, no count shall be taken. Also, the magnification of the microscope shall be so adjusted that the number of ferrite crystal grain to be intercepted by one segment will be not less than 10 within one visual field and the measurement shall be continued for several visual fields until
26、those grains amount to not less than 50. PROTECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/26/2007 01:05:16 MDTNo reproduction or networking permitted without license from IHS
27、-,-,- 4 G 0552 : 1998 1 -1 Remarks: 2 3 4 5 6 7 8 o 1 2 3 4 5 6 12 3 4 5 6 7 8 34 5 6 7 8 9 10 For the method for observing microphotograph and observation observation. with a microscope, there are on ground glass excepting visual 6 Method of determining grain size in each visual field 6.1 Compariso
28、n method 6.1.1 The grain size measured under a microscope shall be compared with the standard figure in Attached Fig. 1 to determine a corresponding grain size number. As a rule, the microscope in this case shall have a magnification of 100, th.e actual visual field shall be a circle of 0.8 mm diame
29、ter? and the size and shape of the projected image or the photographic print shall be a circle of 80 mm diameter. 6.1.2 For grain sizes falling between two consecutive grain size numbers, the smaller grain size number shall be used, but the number of 0.5 shall be added to that number. 6.1.3 When it
30、is difficult to make a determination under a microscope of 100 magnification? 50 or 200 magnification may be used. However, at that time, as given in Table 2, for example, at 50 magnification, the grain size number, thus obtained shall be decreased by 2, and at 200 magnification, the grain size numb
31、er shall be increased by 2. Table 2 Relation of grain size number to ordinary magnification Magni- fication of image 50 100 200 6.1.4 be determined by eye. For mixed grains, the proportion of the areas of each grain size number shall 6.1.5 In the case where pearlite and the like are mixed in great n
32、umbers so far as the mixed state is banded or granular, the area proportion of the mixed structure and of ferrite crystal grain shall be determined by eye. Subsequently, determination of a corresponding grain size number for only the ferrite crystal grain shall be made by comparison with the standar
33、d figure in Attached Fig. 1. Remarks: Attached Fig. 2 indicates the presence of a pearlite phase in the mixture. 6.2 Intercept method 6.2.1 on the basis of the number of ferrite crystal grain measured under a microscope. The grain size number shall be determined by formula (1) or Attached Fig. 3 PRO
34、TECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/26/2007 01:05:16 MDTNo reproduction or networking permitted without license from IHS -,-,- 5 G 0552 : 1998 Grain size No. in F!:i
35、l Mean grain Grain each visual field fields size No. size a b axb g ! 6 . 2 . 2 In the case where the pearlite and the like are mixed in great numbers, the area proportion of the mixed structure and of ferrite crystal grain shall be determined by an appropriate method (j and then the number of cryst
36、al grain in square 25 mm2 at 100 magnification shall be measured by intercept method. The results shall be converted into the number of ferrite crystal grain per 25 mm2 square to obtain the grain size number determined by formula (1) or by Attached Fig. 3. I I I Note (l) For example, point counting
37、method, gravimetric method, photo- tube method, linear analysis method, etc. I I 6 . 3 between the purchaser and supplier. In this case, Annex 1 applies. The judging method by a counting method may be used as agreed upon 7 Method for synthetic determination 7 . 1 In comparison method, the mean grain
38、 size number which derives from the method of determining grain size in each visual field in 6 . 1 by the formula as shown below shall be taken as the grain size of the steel. The mean grain size number shall be rounded off to the first decimal place. Table 3 shows an example. The number of visual f
39、ields observed shall be, as a rule, from 5 to 10. where, g : mean grain size number a : grain size number in each visual field b : number of visual fields indicating the identical grain size number Table 3 Calculation of grain size (example) 7 I 21141 II Total I1O165I I I 7.2 shall be taken as the g
40、rain size of the steel. In intercept method, the grain size number obtained by the method under 6 . 2 7 . 3 synthetic mean values of the proportion of area of each grain size number. For mixed grain under 6.1.4, the ratio of the mixture shall be determined by the 7.4 agreed upon between the purchase
41、r and supplier. In this case, Annex 2 applies. The judging method by the intersected segment (grain size) may be used as PROTECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/26/20
42、07 01:05:16 MDTNo reproduction or networking permitted without license from IHS -,-,- 6 G 0552 : 1998 8 Marking 8.1 Marking shall be made on the basis of the results of synthetic determination in order of the symbol(2) for the type of testing method, the symbol(3) for the tested plane, the grain siz
43、e, and the number of visual fields, as given below. Notes (2) Symbols for the types of testing methods shall be as follows: FGc : comparison method FGt : intercept method Symbols for the planes tested shall be as follows; V : vertical cross section P : parallel section S : surface (3) Example 1 For
44、not mixed grain FGc-V3.5 (A grain size of 3.5 in vertical cross section derived by synthetic determination obtained from 10 visual fields by Comparison Method as outlined in 5.1.) FGt-P6.5 . (A grain size of 6.5 in a parallel section derived by Intercept Method as outlined in 5.2.) F G C - V . -IA G
45、rain size No. 5 Grain size No. 6 Attached Fig. 1 (continued) PROTECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/26/2007 01:05:16 MDTNo reproduction or networking permitted witho
46、ut license from IHS -,-,- 10 G 0552 : 1998 Grain size No. 7 Attached Fig. 1 (concluded) PROTECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/26/2007 01:05:16 MDTNo reproduction or
47、 networking permitted without license from IHS -,-,- A C 11 G 0552 : 1998 B D Attached Fig. 2 Informative figure of microstructures mixed with pearlite (100 magnifications) PROTECTED BY COPYRIGHT Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/11
48、11111001, User=Wing, Bernie Not for Resale, 03/26/2007 01:05:16 MDTNo reproduction or networking permitted without license from IHS -,-,- 12 G 0552 : 1998 Photo identifi- cation No. Pearlite area Grain size Re- % number marks A 6 Granular structure Granular 6.5 structure 5.9 7 8.8 C E Attached Fig. 2 Baud structure 8.3 7 (concluded) D E Number of crystal grains per 25 mm2 n (at 100 magnifications) Granular structure 20.4 7.5 ,B,a,UCture 15.2 6 Attached Fig. 3 Relationship of grain size num