1、Designation: A531/A531M 13A531/A531M 18Standard Practice forUltrasonic Examination of Turbine-Generator Steel RetainingRings1This standard is issued under the fixed designation A531/A531M; the number immediately following the designation indicates the yearof original adoption or, in the case of revi
2、sion, the year 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 practice covers ultrasonic examination of turbine-generator retaining rings produced in accord
3、ance with SpecificationsA288 and A289/A289M with an inside diameter to wall thickness ratio equal to or greater than 5:1 and with wall thicknesses from1 to 4 in. 25 to 102 mm.1.2 Forgings may be inspected by either the contact or the immersion methods, or combinations thereof, as agreed upon between
4、the manufacturer and the purchaser.1.3 Supplementary requirements of an optional nature are provided for use 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
5、 inch-pound and SI units; however, unless the purchase order or contract specifies the applicable“M” specification designation (SI units), the inch-pound units shall apply. The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. Within the practice, the SI
6、units are shown in brackets. The values stated in each systemmay not be exact equivalents; therefore, each 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 saf
7、ety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.6 This international standard was developed in
8、 accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 A
9、STM Standards:2A288 Specification for Carbon and Alloy Steel Forgings for Magnetic Retaining Rings for Turbine GeneratorsA289/A289M Specification for Alloy Steel Forgings for Nonmagnetic Retaining Rings for GeneratorsE127 Practice for Fabrication and Control of Aluminum Alloy Ultrasonic Standard Ref
10、erence BlocksE317 Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-EchoTesting Instruments and Systems without theUse of Electronic Measurement Instruments2.2 Other Documents:ANSI/ASME B46.1 Surface Texture (Surface Roughness, Waviness and Lay)3Recommended Practice No. SNT-TC-
11、1A Personnel Qualification and Certification in Nondestructive Testing43. Personnel Requirements3.1 Personnel performing ultrasonic examinations to this practice shall be qualified and certified in accordance with a writtenprocedure conforming to Recommended Practice No. SNT-TC-1A or other national
12、standard acceptable to both the purchaser andthe supplier.1 This practice is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloysand is the direct responsibility of Subcommittee A01.06 onSteel Forgings and Billets.Current edition approved May 1, 2013May 1, 2018.
13、Published June 2013May 2018. Originally approved in 1965. Last previous edition approved in 20122013 asA531/A531M 12.A531/A531M 13. DOI: 10.1520/A0531_A0531M-13.10.1520/A0531_A0531M-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm
14、.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.4 Available from American Society for Nondestru
15、ctive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.This document is not an ASTM standard and 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 technica
16、lly possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only 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 sta
17、ndardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Ordering Information4.1 When this practice is to be applied to an inquiry, contract, or order, the purchaser shall so state and shall also furnish thefollowing information:4.1.1
18、The method or combination of methods to be used for inspection.4.1.2 The frequency to be used for conducting each inspection.4.1.3 Report requirements including C-scan plot, if applicable.4.1.4 Supplementary requirements, if any.5. General Requirements5.1 As far as possible the entire volume of the
19、retaining rings shall be subject to ultrasonic inspection. Circumferential and axialfaces shall be machined flat and parallel to one another.5.2 The ultrasonic inspection shall be performed after final processing and heat treatment for properties, unless otherwisespecified in the order or contract.5
20、.3 Rings may be tested either stationary (contact) or while rotating (immersion). If not specified by the purchaser, acombination of methods may be used at the manufacturers option. Scanning speed shall not exceed 6 in./s 15 cm/s, unlessautomatic recording (C-scan) equipment is employed.5.4 To ensur
21、e complete coverage (during contact testing), the search unit shall be indexed no more than 75 % of the transducerwidth with each pass of the search unit. During immersion testing establish a transducer index adjustment which will ensurecomplete coverage with sufficient overlap.5.5 During the testin
22、g, a combination of methods and frequencies of 1 MHz, 2 MHz, 214 MHz, and 5 MHz may be used foraccurately locating, determining orientation, and defining specific discontinuities detected during overall scanning.5.6 For reporting purpose, location of indications shall be circumferentially defined by
23、 clock position. The test notch or a similarlocator, such as a reference line bisecting the serial number, shall be used to define and identify the 12 oclock position.6. Apparatus6.1 Electronic ApparatusA pulse-echo instrument permitting inspection frequencies of at least 1 to 5 MHz is required. The
24、accuracy of discontinuity 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
25、broadband transducer, or a narrow-band tuned transducer of known andmatching frequency.6.1.1 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 equip
26、ment function. The date of the lastcalibration and the date of the next required calibration shall be displayed on the test equipment.6.1.2 The horizontal linearity shall be checked on a distance calibration bar using the multiple order technique (see PracticeE317). The horizontal linearity shall be
27、 62 % of the metal path.6.1.3 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
28、 bar and the forging shall then be made.6.1.4 When the immersion method of inspection is employed, suitable equipment must be available so that the retaining ringscan be immersed in a liquid coupling agent or can be subject to inspection by the use of a column or stream of the couplant throughan app
29、ropriate container attached to the part or transducer. Equipment must also include fixturing for smooth mechanical rotationof the part or the transducer during scanning.6.2 AmplifierThe amplifier and display shall provide linear response within 62 %, up to 100 % of full screen height.6.2.1 Amplifier
30、 CalibrationAn amplifier vertical linearity check shall be made prior to performing the test by observing amultiple order pattern from a calibration block using a 2 or 2.25 MHz transducer (see Practice E317). The first back reflection shallbe set at 100 % of full screen height. The higher order back
31、 reflections, 10 % and higher in amplitude, shall also be positionedon the screen and their amplitudes noted. The first back reflection shall be reduced to 50 % and then 25 % of full screen height.The amplitudes of the higher order back reflections shall be noted at each step. The vertical linearity
32、 will be considered acceptableif the signal heights of the higher order reflections decrease in proportion to the decrease set for the first back reflection. Themaximum acceptable error for the decrease of the higher order reflections is the greater of 65 % of the expected back reflectionheight or 6
33、2 % of full screen height.6.3 Signal AttenuatorThe instrument shall contain a calibrated gain control or signal attenuator that meets the requirementsof Practice E317 (in each case, accurate within 65 %) that will allow indications beyond the linear range of the instrument to bemeasured. It is recom
34、mended that these controls permit signal adjustments up to 25 to 1 (28 dB).6.4 Search Units:A531/A531M 1826.4.1 Contact Method:6.4.1.1 A 2.25, 2.0 or 1.0-MHz, 45 angle beam shear wave search unit shall be employed for shear wave testing (2.0 or 2.25MHz shall be used unless acoustic attenuation of th
35、e material is such that 1 MHz must be employed to obtain adequate penetrationof the ring section). Adequate penetration is the ability to clearly resolve the calibration notch above resultant noise level.6.4.1.2 A5, 2.25, 2.0 or 1-MHz, 34 to 118-in. 20 to 30-mm diameter, longitudinal wave transducer
36、 shall be used for performingthe longitudinal wave test.6.4.1.3 Acrylic resin shoes ground to the curvature of the retaining ring may be used to maintain the optimum contact anglebetween the transducer and outside diameter of the ring.6.4.1.4 When agreed upon between the purchaser and supplier, alte
37、rnative test frequencies may be used to perform the requiredtests.6.4.2 Immersion Method:6.4.2.1 A 5, 2.25, 2.0 or 1-MHz transducer, 34 to 1 in. 20 to 30 mm in diameter, suitable for water immersion, shall be usedfor performing the required test.6.4.2.2 The manipulator (holder) for the search tube o
38、r transducer, or both, shall provide for angular manipulation of thetransducer for optimum response from the internal discontinuities. The tolerance or play present in the manipulation and in thetraversing unit should not be excessive so as to prevent ultrasonic examination at the required sensitivi
39、ty level.6.4.2.3 When agreed upon between the purchaser and supplier, alternative test frequencies may be used to perform the requiredtests.6.4.2.4 Accessory EquipmentCoaxial cables and search tubes used in conjunction with the electronic apparatus capable ofconducting the electrical pulses while im
40、mersed in a liquid, and collimators for shaping the sound beam may be used.6.5 Recording instruments or alarm systems, or both, may be used, provided sufficient range and sensitivity are available toproperly monitor the test.7. Preparation of the Forging for Ultrasonic Examination7.1 Surface roughne
41、ss on the outside and inside diameter and radical face surfaces of the ring shall not exceed an Ra of 125in. 3.18 m (Ra is defined in ANSI/ASME B46.1), and waviness shall not exceed 0.001 in. 0.02 mm measured in both theaxial and circumferential directions. The radical faces of the ring shall be suf
42、ficiently perpendicular to the axis of the forging topermit axial tests.7.2 All surfaces of the ring to be examined shall be free of extraneous material such as surface tears, loose scale, machiningor grinding particles, paint, and other foreign matter.8. Ultrasonic Couplants8.1 For contact testing,
43、 a suitable couplant, such as clean SAE 20 motor oil, shall be used to couple the transducer to testsurfaces.8.2 For immersion testing, a liquid such as water, oil, glycerin, etc., capable of conducting ultrasonic vibrations from thetransducer to the material being tested shall be used. Rust inhibit
44、ors, softeners, and wetting agents may be added to the couplant.The couplant liquid with all additives should not be detrimental to the surface condition of the test specimen or the container, andit should wet the surface of the material to provide an intimate contact. Couplant may be heated to a co
45、mfortable workingtemperature and must be free of air bubbles.9. Method for Shear Wave Testing9.1 Calibration Reference:9.1.1 Place a calibration V-shaped notch, with an included angle of 60 to 90 and 14 in. 6.35 mm long, in the outside diametersurface of the ring at a sufficient distance from the en
46、d of the ring to eliminate side wall interference. Determine the location ofthe notch by scanning the ring at a sensitivity high enough to show the material structure and with the shear wave beam directedcircumferentially. Using this procedure, then locate the notch in an area representative of the
47、ring material.9.1.2 Place the notch axially in the ring to a depth of 1 % of the wall thickness or 0.020 in. 0.51 mm, whichever is greater.Make the depth measurement after removal of the upset material adjacent to the notch.9.1.3 For the inspection of finish machined rings, an outside reference bloc
48、k of the same alloy, wall thickness, and curvatureas the ring being tested may be used. The block must be at least 4 in. 10 cm wide and long enough to permit three bounces fromthe reference notch.9.1.4 For axial shear wave examination by the immersion method, place a circumferentially oriented notch
49、 into the outsidediameter surface of the ring at a sufficient distance from the end of the ring so that it can be clearly resolved from the outsidediameter corner reflection. Dimensions of notch shall be the same as described in 9.1.1.9.2 Contact Method for Equipment Calibration:9.2.1 Connect the 2.25-MHz, 2.0-MHz or 1-MHz angle beam search unit to the test instrument and place it directly over thecalibration notch with the crystal directed circumferentially. Move the search unit circumferentially, directing the sound beamA531/A531M 183towa
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