1、Designation: A745/A745M 12A745/A745M 15Standard Practice forUltrasonic Examination of Austenitic Steel Forgings1This standard is issued under the fixed designation A745/A745M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the yea
2、r of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This practice2 covers straight and angle beam contact, pulse-echo ultrasonic examination of austenitic steel for
3、gingsproduced in accordance with Practice A388/A388M and Specifications A965/A965M and A1049/A1049M.1.2 Ultrasonic examination of nonmagnetic retaining ring forgings should be made to Practice A531/A531M rather than thispractice.1.3 Supplementary requirements of an optional nature are provided for u
4、se at the option of the purchaser. The supplementaryrequirements shall apply only when specified individually by the purchaser in the purchase order or contract.1.4 This practice is expressed in inch-pound and SI units; however, unless the purchase order or contract specifies the applicable“M” speci
5、fication designation (SI units), the inch-pound units shall apply. The values stated in either inch-pound units or SI unitsare to be regarded separately as standard. Within the practice, the SI units are shown in brackets. The values stated in each systemmay not be exact equivalents; therefore, each
6、 system shall be used independently of the other. Combining values from the twosystems may result in nonconformance with the standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to est
7、ablish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:3A388/A388M Practice for Ultrasonic Examination of Steel ForgingsA531/A531M Practice for Ultrasonic Examination of Turbine-Generator Steel Re
8、taining RingsA788/A788M Specification for Steel Forgings, General RequirementsA965/A965M Specification for Steel Forgings, Austenitic, for Pressure and High Temperature PartsA1049/A1049M Specification for Stainless Steel Forgings, Ferritic/Austenitic (Duplex), for Pressure Vessels and RelatedCompone
9、ntsE317 Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-EchoTesting Instruments and Systems without theUse of Electronic Measurement InstrumentsE428 Practice for Fabrication and Control of Metal, Other than Aluminum, Reference Blocks Used in Ultrasonic Testing2.2 American Soc
10、iety for Nondestructive Testing Document:4SNT-TC-1A Recommended Practice for Nondestructive Personnel Qualification and Certification3. Ordering Information3.1 When this practice is to be applied to an inquiry or purchase order, the purchaser shall furnish the following information:3.1.1 Quality lev
11、el of examination (see Section 12).3.1.2 Additional requirements to this practice.3.1.3 Applicability of supplementary requirements (see Supplementary Requirements section).1 This practice is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloysand is the direct r
12、esponsibility of Subcommittee A01.06 onSteel Forgings and Billets.Current edition approved March 1, 2012May 1, 2015. Published March 2012May 2015. Originally approved in 1977. Last previous edition approved in 20092012 asA745/A745M 94A745/A745M 12. (2009). DOI: 10.1520/A0745_A0745M-12.10.1520/A0745_
13、A0745M-15.2 For ASME Boiler and Pressure Vessel Code applications see related Specification SA-745/SA-745M in Section II of that Code.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume infor
14、mation, refer to the standards Document Summary page on the ASTM website.4 Available from theAmerican Society for NondestructiveTesting, 1711Arlingate Lane,Testing (ASNT), P.O. Box 28518, 1711Arlingate Ln., Columbus, OH 432280518.43228-0518, http:/www.asnt.org.This document is not an ASTM standard a
15、nd is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only
16、 the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.4 Supplementary re
17、quirements, if any.3.2 When specified, the manufacturer shall submit an examination procedure for purchaser approval that shall include, but notbe limited to, a sketch of the configuration as presented for ultrasonic examination showing the surfaces to be scanned, scanningdirections, notch locations
18、 and sizes (if applicable), extent of coverage (if applicable), and an instruction listing calibration andinspection details and stage of manufacture.4. Apparatus4.1 Electronic ApparatusA pulse-echo instrument permitting inspection frequencies of 1, 2.25, and 5 MHz is required. Theaccuracy of discon
19、tinuity amplitude analysis using this practice involves a knowledge of the true operating frequency of thecomplete inspection system. One of the best ways to obtain the desired accuracy is by use of a tuned pulser and narrow bandamplifier of known frequency response, with either a broadband transduc
20、er, or a narrow-band tuned transducer of known andmatching frequency.4.1.1 Apparatus Qualification and CalibrationBasic qualification of the ultrasonic test instrument shall be performed atintervals not to exceed 12 months or whenever maintenance is performed that affects the equipment function. The
21、 date of the lastcalibration and the date of the next required calibration shall be displayed on the test equipment.4.1.2 The horizontal linearity shall be checked on a distance calibration bar using the multiple order technique (see PracticeE317). The horizontal linearity shall be 62 % of the metal
22、 path.4.1.3 The accuracy of the linearity shall be checked by ultrasonically verifying the thickness of the component in at least onelocation beyond the near field of the transducer. If necessary, minor adjustments for differences in the ultrasonic velocities betweenthe calibration bar and the forgi
23、ng shall then be made.4.2 AmplifierThe amplifier and display shall provide linear response within 62 %, up to 100 % of full screen height.4.2.1 Amplifier CalibrationAn amplifier vertical linearity check shall be made prior to performing the test by observing amultiple order pattern from a calibratio
24、n block using a 2.25 MHz transducer (see Practice E317). The first back reflection shall beset at 100 % of full screen height. The higher order back reflections, 10 % and higher in amplitude, shall also be positioned onthe screen and their amplitudes noted. The first back reflection shall be reduced
25、 to 50 % and then 25 % of full screen height. Theamplitudes of the higher order back reflections shall be noted at each step. The vertical linearity will be considered acceptable ifthe signal heights of the higher order reflections decrease in proportion to the decrease set for the first back reflec
26、tion. Themaximum acceptable error for the decrease of the higher order reflections is the greater of 65 % of the expected back reflectionheight or 62 % of full screen height.4.3 Signal AttenuatorThe instrument shall contain a calibrated gain control or signal attenuator that meets the requirementsof
27、 Practice E317 (in each case, accurate within 65 %) that will allow indications beyond the linear range of the instrument to bemeasured. It is recommended that these controls permit signal adjustments up to 25 to 1 (28 dB).4.4 Search Units:4.4.1 The maximum nominal active area of 112 in.2 970 mm2 wi
28、th 12-in. 13 mm minimum to 118-in. 30 mm maximumdimensions or 34-in. 20 mm diameter minimum dimension shall be used for straight-beam scanning.4.4.2 Angle-beam scanning transducers shall have a nominal active area of 12 to 1 in.2 325 to 650 mm2. The search unit usedfor angle-beam examination shall p
29、roduce a beam angle of 30 to 70 in the material.4.4.3 Other search units, including frequencies other than those listed in Section 8, may be used for evaluating and pinpointingindications of discontinuities.4.5 CouplantA suitable couplant having good wetting characteristics shall be used between the
30、 transducer and theexamination surface. The same couplant shall be used for calibration and examination.4.6 Reference Blocks:4.6.1 All ultrasonic standard reference blocks shall be in accordance with the general guidelines of Practice E428. However,absolute conformance to Practice E428 is not mandat
31、ory due to the nature of the material covered by this practice.4.6.2 The reference block grain size, as measured by the relative acoustic penetrability of the reference blocks, should bereasonably similar to the forging under examination. However, it must be recognized that large austenitic forgings
32、 varyconsiderably in acoustic penetrability throughout their volume due to variations in grain size and structure. Reference blocksshould be chosen that reasonably approximate the average penetrability of the forging under examination. Supplementary blocksof coarser or finer grain may be used for ev
33、aluation of indications as covered in Section 11.4.6.3 As an alternative method, where practicable, the appropriate size of reference hole (or holes) or notches may be placedin representative areas of the forging for calibration and examination purposes when removed by subsequent machining. Whenhole
34、s or notches are not removed by subsequent machining, the purchaser must approve the location of holes or notches.5. Personnel Requirements5.1 Personnel performing the ultrasonic examinations to this practice shall be qualified and certified in accordance with a writtenprocedure conforming to Recomm
35、ended Practice No. SNT-TC-1A or another national standard that is acceptable to both thepurchaser and the supplier.A745/A745M 1526. Forging Conditions6.1 Forgings shall be ultrasonically examined after heat treating.6.2 The surfaces of the forging to be examined shall be free of extraneous material
36、such as loose scale, paint, dirt, etc.6.3 The surface roughness of scanning surfaces shall not exceed 250 in. 6 m unless otherwise stated in the order or contract.contract where the definition for surface finish is as per Specification A788/A788M.6.4 The forgings shall be machined to a simple config
37、uration, that is, rectangular or parallel or concentric surfaces wherecomplete volumetric coverage can be obtained.6.5 In certain cases, such as with contour forged parts, it may be impractical to assure 100 % volumetric coverage. Such forgingsshall be examined to the maximum extent possible. A proc
38、edure indicating the extent of examination coverage shall be submittedfor the purchasers approval (see 3.2).7. Procedure7.1 Perform the ultrasonic examination after heat treatment when the forging is machined to the ultrasonic configuration butprior to drilling holes, cutting keyways, tapers, groove
39、s, or machining sections to final contour.7.2 To ensure complete coverage of the forging volume when scanning, index the search unit with at least 15 % overlap witheach pass.7.3 The scanning rate shall not exceed 6 in. 150 mm/s.7.4 Scan all regions of the forging in at least two perpendicular direct
40、ions to the maximum extent possible.7.5 Scan disk and disk-type forgings using a straight beam from at least one flat face and radially from the circumference whenpracticable. For the purposes of this practice, a disk is a cylindrical shape where the diameter dimension exceeds the heightdimension. D
41、isk-type forgings made as upset-forged “pancakes” shall be classified as disks for inspection purposes although at thetime of inspection, the part may have a center hole, counterturned steps, or other detail configuration.7.6 Scan cylindrical sections, ring and hollow forgings from the entire extern
42、al surface (sides or circumference), using thestraight-beam technique, and scan the forging in the axial direction to the extent possible. When the length divided by the diameterratio (slenderness ratio) exceeds 6 to 1 (or axial length exceeds 24 in. 600 mm), scan axially from both end surfaces to t
43、he extentpossible. If axial penetration is not possible due to attenuation, angle-beam examination directed axially may be substituted in placeof axial straight beam. Examine ring and hollow forgings having an outside-diameter to inside-diameter ratio of less than 2 to 1and a wall thickness less tha
44、n 8 in. 200 mm by angle-beam techniques from the outside diameter or inside diameter, or both, usingfull node or half-node technique (see 10.1.2 and 10.1.3) as necessary to achieve either 100 % volumetric coverage or the extentof coverage defined by an approved procedure (see 3.2).8. Examination Fre
45、quency8.1 Perform all ultrasonic examination at the highest frequency practicable (as specified in 8.1.1, 8.1.2, or 8.1.3) that willadequately penetrate the forging thickness and resolve the applicable reference standard. Include in the ultrasonic examinationreport the examination frequency used. De
46、termine the test frequency at the time of actual examination by the following guidelines:8.1.1 The nominal test frequency shall be 2.25 MHz. Use of this frequency will generally be restricted due to attenuation.8.1.2 One megahertz is acceptable and will be the frequency generally applicable.8.1.3 Wh
47、en necessary, due to attenuation, 0.5-MHz examination frequency may be used. The purchaser may request notificationbefore this lower frequency is employed.8.1.4 In the event that adequate penetration of certain regions is not possible even at 0.5 MHz, alternative nondestructiveexamination methods (s
48、uch as radiography) may be employed to ensure the soundness of the forging by agreement between thepurchaser and the manufacturer.9. Straight-Beam Examination9.1 Method of Calibration:9.1.1 Perform calibration for straight-beam examination on the flat-bottom hole size determined by the applicable qu
49、ality level(see Section 12).9.1.2 Determine the calibration method by the test metal distance involved.9.1.2.1 Thicknesses up to 6 in. 150 mm may be examined using either the single-block or the distance-amplitude curvecalibration method.(a) Single-Block MethodEstablish the test sensitivity on the reference standard representing the forging thickness. Drillflat-bottom holes normal to the examining surface, to midsection in material up to 1.5 in. 40 mm in thickness and at least 0.75in. 20 mm in depth but no deeper than midsection in thick
