1、Designation: E 588 03Standard Practice forDetection of Large Inclusions in Bearing Quality Steel bythe Ultrasonic Method1This standard is issued under the fixed designation E 588; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This practice covers a procedure for the rating ofrectangular steel sections by immersion ultrasonic techni
3、ques.Its purpose is to provide information on the content of largeinclusions or clusters of small inclusions for determining thesuitability of a steel lot for bearing applications. This practicein no manner defines or establishes limits of acceptability.1.2 For this document, large inclusions are de
4、fined inultrasonic terms as those having a reflecting area equivalent toor larger than a164-in. diameter flat-bottom hole in a steelreference block of similar properties and thickness. In metal-lographic terms, large inclusions, defined in this way, are ofapproximately the same size as the smallest
5、detectable sizesrevealed by the macroscopic methods of Practice E45. In somecases, inclusions smaller than those described previously canbe detected either individually or in clusters, depending ontheir type, chemical composition, orientation to the ultrasonicbeam and distance from the sound entry s
6、urface of thespecimen.1.3 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
7、to use.2. Referenced Documents2.1 ASTM Standards:E45 Test Methods for Determining the Inclusion Contentof Steel2E 214 Practice for Immersed Ultrasonic Examination by theReflection Method Using Pulsed Longitudinal Waves3E 428 Practice for Fabrication and Control of Steel Refer-ence Blocks Used in Ult
8、rasonic Examination3E 543 Practice for Agencies Performing NondestructiveTesting3E 1316 Terminology for Nondestructive Examinations32.2 ASNT Documents:SNT-TC-1A Recommended Practicefor Personnel Qualifi-cation and Certification in Nondestructive Testing4ASNT-CP-189 STandard for Qualification and Cer
9、tificationof Nondestructive Testing Personnel43. Terminology3.1 DefinitionsFor definitions of terms used in this prac-tice, see Terminology E 1316.4. Basis of Application4.1 Agreements Between Using PartiesIn order for thispractice to be effectively used, the following items requireagreement between
10、 the using parties.4.1.1 Evaluation of Nondestructive Testing AgenciesAnagreement is required as to whether the nondestructive testingagency, as defined in Practice E 543, must be formally evalu-ated and qualified to perform the examination. If such anevaluation is specified, a documented procedure
11、such asPractice E 543 shall be used as the basis for evaluation.4.1.2 Personnel QualificationNondestructive testing(NDT) personnel shall be qualified in accordance with anationally recognized NDT personnel qualification practice orstandard such as ASNT CP-189, SNT-TC-1A, or a similardocument. The pr
12、actice or standard used and its applicablerevision shall be specified in the contractual agreement be-tween the using parties.4.1.3 Search Unit Performance TestsAnnex A1 definesthe minimum manufacturers specifications for search units tobe used with this practice. The extent of testing and verificat
13、ionof these parameters to be performed by the manufacturer shallbe specified in the contractual agreement between the usingparties.5. Summary of Practice5.1 The general technique used is immersion ultrasonictesting by the reflection method using pulsed longitudinalwaves such as described in Practice
14、 E 214. Specific additionalrequirements for sample preparation, equipment operatingparameters and calibration, and expression of results are1This practice is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.2
15、8 on Bearing Steels.Current edition approved April 10, 2003. Published July 2003. Originallyapproved in 1976. Last previous edition approved in 1995 as E 588 95.2Annual Book of ASTM Standards, Vol 03.01.3Annual Book of ASTM Standards, Vol 03.03.4Available from the American Society for Nondestructive
16、 Testing, 1711 Arlin-gate Plaza, P.O. Box 28518, Columbus, OH 43228-0518.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.delineated in this procedure. Special focused
17、search unitshaving operating characteristics as defined in Annex A1 arerequired.6. Significance and Use6.1 Comparison with Other Inclusion Rating MethodsBecause the test is performed on a volumetric rather than asurface-examination basis, the ultrasonic method is inherentlybetter able to detect infr
18、equently occurring large inclusions orclusters of small inclusions than eddy current, magnetic par-ticle, microscopical, or macroscopic examination procedures.6.2 Limitation of Inclusion Size and TypeA limitation ofthe method is that it will not detect all inclusions. Inclusionchemistry, size, shape
19、, location, and distribution may limit theability of the method to provide indications distinct from thosegenerated by the surrounding metallurgical structure. Therecommended practice is only meaningfully applicable toexamination of steel wherein the inclusion size and type arewithin the detection c
20、apabilities of the method. For steelwherein inclusion size, dispersion, and chemistry preventoptimum inclusion detection by ultrasonics, microscopicalmethods detailed in Practice E45may be applied.7. Interference7.1 Reflections from Multiple InclusionsAn ultrasonicindication can represent the reflec
21、tion from a single inclusion;however, it typically represents the vector summation ofreflections from clusters of small inclusions contained within avolume of a few cubic millimetres.7.2 Response as a Function of Inclusion TypeThe indi-vidual inclusion reflections can have different amplitudesbecaus
22、e of different inclusion characteristics. In addition, theindividual reflections may have different phase characteristicswhen arriving at the search unit if the travel distances aredifferent.8. Apparatus8.1 Equipment RequiredAn equipment system with thefollowing components is needed to conduct this
23、test: ultrasonictest instrument, search unit, a means of recording signals ofvarious amplitudes, a system reference block, instrumentcalibration block, and an immersion tank with suitable scan-ning accessories.8.2 Ultrasonic InstrumentThe ultrasonic instrument shallbe capable of generating and recei
24、ving electrical pulses of10-MHz frequency at levels compatible with the test require-ments. It shall have both an A-scan presentation and an analogor digital output. It shall be the ultrasonic instrument manu-facturers responsibility that instruments supplied for use withthis test meet the minimum r
25、equirements delineated in thisrecommended practice.8.2.1 Receiver CharacteristicsThe center frequency shallbe 10 6 0.5 MHz. The bandpass of the receiver shall be at least1.3 MHz (3 dB points).8.2.2 Dynamic RangeThe dynamic range of the instru-ment shall permit detection of steel balls with a 16-to-1
26、diameter ratio at a given sensitivity. Balls shall be placed inwater at the focal point of the search unit. Each size ball withinthis range shall give a significantly different amplitude ofindication.8.2.3 StabilityThe signal amplitude of a usable full-scaleindication shall not vary more than 5 % af
27、ter1hofinstrumentwarm-up, and preferably by less than 2 % (4-h test with airtemperature being held to 61.2C over a temperature range of17.5 to 25.5C).8.2.4 Sweep Length and LinearitySweep length of oscil-loscope presentation shall be capable of being adjusted torepresent 1 mm = 1.27 mm of steel. A m
28、inimum of 80 mm ofthe sweep display shall be linear to within 5 % of full scale.The signal amplitude of an indication from a target shall notvary more than 64 % over the gated portion of the sweepemployed in calibration and testing.8.2.5 Repetition RateThe repetition rate of the pulsershall not be l
29、ess than 500 pulses per second.8.3 Search UnitsUltrasonic search units for this test shallbe spherically focused immersion-type units. Uniform perfor-mance characteristics of search units are critical for obtainingreproducible test measurements. (See Annex A1, which delin-eates search unit performan
30、ce characteristics to be met bysearch unit manufacturers.) Performance characteristics ofsearch units requiring consideration are: the uniformity of focaldistance in water, center frequency, frequency spectrum, lensradius, width of field, and beam symmetry.8.3.1 Focal LengthA focused beam of radiate
31、d ultrasonicenergy is recommended to provide lateral resolution of smalldefects and to improve testing sensitivity in the region near thefocal point. The focal length of a search unit is defined in thisdiscussion as the distance in water, on the search unit axis,between the search unit and the surfa
32、ce of a12-in. or 12-mmdiameter ball target at which the highest reflection amplitudeindication is obtained. Different focal length transducers maybe used to obtain optimum response at selected distances belowthe test sample surface. (Variation of search unit-to-specimensurface water path would also
33、affect the focal point within thetest sample.)8.3.2 Search Unit CharacteristicsSearch units generallyemployed have the following frequency and focal length aspurchased:Frequency Focal Length in Water10 6 0.5 MHz 8.2 6 0.3 in. (208.3 6 7.6 mm)8.3.3 Beam SymmetryEach search unit should be rotatedon it
34、s ultrasonic beam axis (not necessarily geometric axis)until a particular circumferential orientation is found whichgives a maximum severity, or count, from the system referenceblock. This search unit orientation shall be identified andemployed in subsequent tests. Search units that exhibit varia-ti
35、ons in indication amplitude in excess of 15 % during rotationshall not be considered satisfactory for the test. There are othermethods, such as optimum response over a precision anduniform taut wire, that have been found to be usable.8.3.4 PerformanceThe performance capabilities of allnew search uni
36、ts shall be verified by an actual test on thesystem reference block. The data obtained for new search unitsE588032should be compared with that obtained for other search unitshaving the same specifications and tested under identicalconditions.8.4 Immersion Tank and AccessoriesAn immersion tankwith as
37、sociated scanning and indexing facilities shall be used.8.4.1 Search Unit AngulationThe tank shall be providedwith a manipulator capable of continuously angulating thesearch unit in two vertical mutually perpendicular planespermitting the required normalization.8.4.2 Scanning and IndexingThe tank br
38、idge and carriageassemblies shall provide X-Y motion to the search unit. Thescanning shall be parallel or perpendicular (depending on theprocedure) to the test specimen axis and the indexing shall beperpendicular to the scanning.8.4.3 Test Specimen MountingThe tank shall be providedwith fixturing pe
39、rmitting the mounting of the entry surface ofthe test specimen parallel to the bridge travel so that thedistance between search unit and specimen remains constantwithin 6164 in. (0.4 mm).8.4.4 Couplant:8.4.4.1 The inspection solution shall consist of tap ordistilled water to which a wetting agent ha
40、s been added todisperse air bubbles. The pH of the water shall be maintainedwithin 712 to 812 . Rust preventives may also be added. Allchemical additives shall be held within concentrations that donot adversely affect test performance. Water temperature mustbe held between 19.5 and 25.5C. It is impo
41、rtant that excessivethermal gradients do not exist between the search unit and thecalibration standards.8.4.4.2 A means of circulating the immersion inspectionsolution shall be employed, when necessary, to dissipatethermal gradients.8.5 Readout EquipmentVarious types of instrumentationhave been empl
42、oyed in conjunction with ultrasonic instrumentsfor many years to determine the number of occurrences ofvarious amplitude indications. These include level counters,pulse counters, integrators, strip chart recorders, B-scan re-corders, C-scan recorders, memory oscilloscopes, and com-puter techniques.
43、With pulse counters, both repetition rate andscanning speed must be held within a 5 % tolerance and,preferably, 2 %.8.6 System Reference BlockA system reference block(defined dimensionally in Section 9.2) is required for initialadjustments and operational testing of the equipment. Thissample should
44、be selected to provide reflection signals at allcounting levels. Depth distribution of inclusions in the selectedreference block should make its response characteristics rela-tively insensitive to minor focal length variations betweendifferent search units. The reference block should give aminimum c
45、hange in total counts of 10 % for each 10 %increase or decrease in amplitude setting. A maximum of 30 %change in count for each 10 % change in amplitude settingshould not be exceeded. It should be suitably protected fromcorrosion to assure its longevity.9. Test Specimens9.1 GeneralTest specimens mus
46、t be either in the rolled orforged condition. If forged, upset forging is prohibited in orderto maintain the rolling direction. Care should be taken not tooverheat the forging to avoid spurious ultrasonic indications.Specimen location and frequency shall be as agreed uponbetween the supplier and the
47、 purchaser.9.2 Specimen Size and ShapeSpecimens shall have aminimum cross-sectional dimension after preparation of 312 in.(88.9 mm). The area scanned shall be sufficient to permittesting of a minimum of 25 in.3(410 cm3) of the specimen. Thetested volume equals the scanned area multiplied by the gate
48、ddepth. If special consideration is given, thinner samples may betested.9.3 Entry Surface FinishThe test surface through whichthe sound enters the specimen shall be machined and ground.This finish in any direction over the surface shall be preferably10 to 80 in. (.25 to 2.0 m). Final material remova
49、l mayrequire a dressed grinding wheel to avoid spurious, near-surface indications. All four sides are to be ground.9.4 Heat TreatmentThermal conditioning of the speci-mens is required to minimize acoustic anomalies. Typical heattreatment may consist of normalizing or quenching and tem-pering, depending on steel type, to meet the ultrasonic penetra-bility requirement of Section 9.5. Certain steels may requirespecial thermal treatment such as a double temper to obtainsuitable acoustic properties.9.5 Ultrasonic PenetrabilityThe ultrasonic penetr
