1、Designation: E1245 03 (Reapproved 2016)Standard Practice forDetermining the Inclusion or Second-Phase ConstituentContent of Metals by Automatic Image Analysis1This standard is issued under the fixed designation E1245; the number immediately following the designation indicates the year oforiginal ado
2、ption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis practice may be used to produce stereological measurements that de
3、scribe the amount, number,size, and spacing of the indigenous inclusions (sulfides and oxides) in steels. The method may also beapplied to assess inclusions in other metals or to assess any discrete second-phase constituent in anymaterial.1. Scope1.1 This practice describes a procedure for obtaining
4、 stereo-logical measurements that describe basic characteristics of themorphology of indigenous inclusions in steels and other metalsusing automatic image analysis. The practice can be applied toprovide such data for any discrete second phase.NOTE 1Stereological measurement methods are used in this
5、practiceto assess the average characteristics of inclusions or other second-phaseparticles on a longitudinal plane-of-polish. This information, by itself,does not produce a three-dimensional description of these constituents inspace as deformation processes cause rotation and alignment of theseconst
6、ituents in a preferred manner. Development of such informationrequires measurements on three orthogonal planes and is beyond the scopeof this practice.1.2 This practice specifically addresses the problem ofproducing stereological data when the features of the constitu-ents to be measured make attain
7、ment of statistically reliabledata difficult.1.3 This practice deals only with the recommended testmethods and nothing in it should be construed as defining orestablishing limits of acceptability.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are inclu
8、ded in thisstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to
9、 use.2. Referenced Documents2.1 ASTM Standards:2E3 Guide for Preparation of Metallographic SpecimensE7 Terminology Relating to MetallographyE45 Test Methods for Determining the Inclusion Content ofSteelE768 Guide for Preparing and Evaluating Specimens forAutomatic Inclusion Assessment of Steel3. Ter
10、minology3.1 Definitions:3.1.1 For definitions of terms used in this practice, seeTerminology E7.3.2 Symbols:A= the average area of inclusions or particles, m2.AA= the area fraction of the inclusion or constituent.Ai= the area of the detected feature.AT= the measurement area (field area, mm2).HT= the
11、 total projected length in the hot-workingdirection of the inclusion or constituent in thefield, m.L= the average length in the hot-working directionof the inclusion or constituent, m.LT= the true length of scan lines, pixel lines, or gridlines (number of lines times the length of thelines divided b
12、y the magnification), mm.n = the number of fields measured.NA= the number of inclusions or constituents of agiven type per unit area, mm2.1This practice is under the jurisdiction of ASTM Committee E04 on Metallog-raphy and is the direct responsibility of Subcommittee E04.14 on QuantitativeMetallogra
13、phy.Current edition approved May 1, 2016. Published May 2016. Originallyapproved in 1988. Last previous edition approved in 2008 as E1245 03(2008).DOI: 10.1520/E1245-03R16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For An
14、nual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Ni= the number of inclusions or constituent particlesor the number of featu
15、re interceptions, in thefield.NL= the number of interceptions of inclusions orconstituent particles per unit length (mm) of scanlines, pixel lines, or grid lines.PPi= the number of detected picture points.PPT= the total number of picture points in the fieldarea.s = the standard deviation.t = a multi
16、plier related to the number of fieldsexamined and used in conjunction with thestandard deviation of the measurements to deter-mine the 95 % CIVV= the volume fraction.X= the mean of a measurement.Xi= an individual measurement. = the mean free path (m) of the inclusion orconstituent type perpendicular
17、 to the hot-working direction.X = the sum of all of a particular measurement overn fields.X2= the sum of all of the squares of a particularmeasurement over n fields.95 % CI = the 95 % confidence interval.% RA = the relative accuracy, %.4. Summary of Practice4.1 The indigenous inclusions or second-ph
18、ase constituentsin steels and other metals are viewed with a light microscopeor a scanning electron microscope using a suitably preparedmetallographic specimen. The image is detected using atelevision-type scanner tube (solid-state or tube camera) anddisplayed on a high resolution video monitor. Inc
19、lusions aredetected and discriminated based on their gray-level intensitydifferences compared to each other and the unetched matrix.Measurements are made based on the nature of the discrimi-nated picture point elements in the image.3These measure-ments are made on each field of view selected. Statis
20、ticalevaluation of the measurement data is based on the field-to-field or feature-to-feature variability of the measurements.5. Significance and Use5.1 This practice is used to assess the indigenous inclusionsor second-phase constituents of metals using basic stereologi-cal procedures performed by a
21、utomatic image analyzers.5.2 This practice is not suitable for assessing the exogenousinclusions in steels and other metals. Because of the sporadic,unpredictable nature of the distribution of exogenousinclusions, other methods involving complete inspection, forexample, ultrasonics, must be used to
22、locate their presence.The exact nature of the exogenous material can then bedetermined by sectioning into the suspect region followed byserial, step-wise grinding to expose the exogenous matter foridentification and individual measurement. Direct size mea-surement rather than application of stereolo
23、gical methods isemployed.5.3 Because the characteristics of the indigenous inclusionpopulation vary within a given lot of material due to theinfluence of compositional fluctuations, solidification condi-tions and processing, the lot must be sampled statistically toassess its inclusion content. The l
24、argest lot sampled is the heatlot but smaller lots, for example, the product of an ingot, withinthe heat may be sampled as a separate lot. The sampling of agiven lot must be adequate for the lot size and characteristics.5.4 The practice is suitable for assessment of the indigenousinclusions in any s
25、teel (or other metal) product regardless of itssize or shape as long as enough different fields can be measuredto obtain reasonable statistical confidence in the data. Becausethe specifics of the manufacture of the product do influence themorphological characteristics of the inclusions, the reportsh
26、ould state the relevant manufacturing details, that is, dataregarding the deformation history of the product.5.5 To compare the inclusion measurement results fromdifferent lots of the same or similar types of steels, or othermetals, a standard sampling scheme should be adopted such asdescribed in Pr
27、actice E45.5.6 The test measurement procedures are based on thestatistically exact mathematical relationships of stereology4forplanar surfaces through a three-dimensional object examinedusing reflected light (see Note 1).5.7 The orientation of the sectioning plane relative to thehot-working axis of
28、the product will influence test results. Ingeneral, a longitudinally oriented test specimen surface isemployed in order to assess the degree of elongation of themalleable (that is, deformable) inclusions.5.8 Oxide inclusion measurements for cast metals, or forwrought sections that are not fully cons
29、olidated, may be biasedby partial or complete detection of fine porosity or micro-shrinkage cavities and are not recommended. Sulfides can bediscriminated from such voids in most instances and suchmeasurements may be performed.5.9 Results of such measurements may be used to qualifymaterial for shipm
30、ent according to agreed upon guidelinesbetween purchaser and manufacturer, for comparison of differ-ent manufacturing processes or process variations, or to pro-vide data for structure-property-behavior studies.6. Interferences6.1 Voids in the metal due to solidification, limited hotductility, or im
31、proper hot working practices may be detected asoxides because their gray level range is similar to that ofoxides.6.2 Exogenous inclusions, if present on the plane-of-polish,will be detected as oxides and will bias the measurements ofthe indigenous oxides. Procedures for handling this situationare gi
32、ven in 12.5.9.3Vander Voort, G. F., “Image Analysis,” Vol 10, 9th ed., Metals Handbook:Materials Characterization, ASM, Metals Park, OH, 1986, pp. 309322.4Underwood, E. E., Quantitative Stereology, Addison-Wesley Publishing Co.,Reading, MA, 1970.E1245 03 (2016)26.3 Improper polishing techniques that
33、 leave excessivelylarge scratches on the surface, or create voids in or aroundinclusions, or remove part or all of the inclusions, or dissolvewater-soluble inclusions, or create excessive relief will bias themeasurement results.6.4 Dust, pieces of tissue paper, oil or water stains, or otherforeign d
34、ebris on the surface to be examined will bias themeasurement results.6.5 If the programming of the movement of the automaticstage is improper so that the specimen moves out from underthe objective causing detection of the mount or air (unmountedspecimen), measurements will be biased.6.6 Vibrations m
35、ust be eliminated if they cause motion inthe image.6.7 Dust in the microscope or camera system may producespurious indications that may be detected as inclusions.Consequently, the imaging system must be kept clean.7. Apparatus7.1 A reflected light microscope equipped with bright-fieldobjectives of s
36、uitable magnifications is used to image themicrostructure. The use of upright-type microscope allows foreasier stage control when selecting field areas; however, thespecimens will require leveling which can create artifacts, suchas scratches, dust remnants and staining, on the polishedsurface (see 1
37、2.2.1). The use of inverted microscopes usuallyresult in a more consistent focus between fields, thereby,requiring less focussing between fields and a more rapidcompletion of the procedure. A scanning electron microscopealso may be used to image the structure.7.2 A programmable automatic stage to co
38、ntrol movementin the x and y directions without operator attention is recom-mended (but not mandatory) to prevent bias in field selectionand to minimize operator fatigue.7.3 An automatic focus device may also be employed iffound to be reliable. Such devices may be unreliable whentesting steels or me
39、tals with very low inclusion contents.7.4 An automatic image analyzer with a camera of adequatesensitivity is employed to detect the inclusions, performdiscrimination, and make measurements.7.5 A computer is used to store and analyze the measure-ment data.7.6 A printer is used to output the data and
40、 relevantidentification/background information in a convenient format.7.7 This equipment must be housed in a location relativelyfree of airborne dust. High humidity must be avoided asstaining may occur; very low humidity must also be avoided asstatic electricity may damage electronic components.Vibr
41、ations, if excessive, must be isolated.8. Sampling8.1 In general, sampling procedures for heat lots or forproduct lots representing material from a portion of a heat lotare the same as described in Practice E45 (MicroscopicalMethods) or as defined by agreements between manufacturersand users.8.2 Cha
42、racterization of the inclusions in a given heat lot, ora subunit of the heat lot, improves as the number of specimenstested increases. Testing of billet samples from the extreme topand bottom of the ingots (after discards are taken) will defineworst conditions of oxides and sulfides. Specimens taken
43、 frominterior billet locations will be more representative of the bulkof the material. Additionally, the inclusion content will varywith the ingot pouring sequence and sampling should test atleast the first, middle and last ingot teemed. The same trendsare observed in continuously cast steels. Sampl
44、ing schemesmust be guided by sound engineering judgment, the specificprocessing parameters, and producer-purchaser agreements.9. Test Specimens9.1 In general, test specimen orientation within the test lot isthe same as described in Practice E45 (Microscopical Meth-ods). The plane-of-polish should be
45、 parallel to the hot-workingaxis and, most commonly, taken at the quarter-thicknesslocation. Other test locations may also be sampled, forexample, subsurface and center locations, as desired or re-quired.9.2 The surface to be polished should be large enough inarea to permit measurement of at least 1
46、00 fields at thenecessary magnification. Larger surface areas are beneficialwhenever the product form permits. A minimum polishedsurface area of 160 mm2is preferred.9.3 Thin product forms can be sampled by placing a numberof longitudinally oriented pieces in the mount so that thesampling area is suf
47、ficient.9.4 Practice E768 lists two accepted methods for preparingsteel samples for the examination of inclusion content usingimage analysis. The standard also lists a procedure to test thequality of the preparation using differential interference con-trast (DIC).10. Specimen Preparation10.1 Metallo
48、graphic specimen preparation must be carefullycontrolled to produce acceptable quality surfaces for imageanalysis. Guidelines and recommended practices are given inMethods E3, and Practices E45 and E768.10.2 The polishing procedure must not alter the true appear-ance of the inclusions on the plane-o
49、f-polish by producingexcessive relief, pitting, cracking or pullout. Minor finescratches, such as from a 1-m diamond abrasive, do notusually interfere with inclusion detection but heavier scratchesare to be avoided. Proper cleaning of the specimen is necessary.Use of automatic grinding and polishing devices is recom-mended.10.3 Establishment of polishing practices should be guidedby Practice E768.10.4 Inclusion retention is generally easier to accomplish ifspecimens are hardened. If inclusion retention is inadequatewith annealed, normalized, or low hardness as-rolledE12
