1、Designation: A939 07 (Reapproved 2012)Standard Practice forUltrasonic Examination from Bored Surfaces of CylindricalForgings1This standard is issued under the fixed designation A939; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、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.1. Scope1.1 This practice covers a basic procedure of ultrasonicallyinspecting cylindrical forgings with bores from th
3、e boresurface.1.2 This practice applies to the manual testing mode. It doesnot restrict the use of other testing modes, such as mechanizedor automated.1.3 This practice applies to cylindrical forgings having boresizes equal to or greater than 2.5 in. (63.5 mm).1.4 The values stated in inch-pound uni
4、ts are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsib
5、ility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Significance and Use2.1 This practice shall be used when ultrasonic inspectionfrom the bore surface is required by the order or specific
6、ationfor inspection purposes in which the acceptance of the forgingis based on limitations of the number, amplitude, or location ofdiscontinuities or a combination thereof, which leads to ultra-sonic indications.2.2 The acceptance criteria shall be stated clearly as orderrequirements.2.3 This practi
7、ce specifies dual search units, which depend-ing on the angle, are sensitive only to 2 to 3 in. into the metalfrom the bore surface.3. General Requirements3.1 As far as possible, the entire bore surface shall besubjected to ultrasonic inspection. It may be impossible toinspect some small portions of
8、 the bore surface because ofchamfers at stepdowns and other local configurations.3.2 The bore ultrasonic inspection shall be performed afterthe final austenitizing and tempering heat treatment for me-chanical properties of the forging, and may be performed eitherprior to or after any subsequent stre
9、ss relieving heat treatment.3.3 The ultrasonic beam shall be introduced radially foroverall scanning.3.4 Forgings may be tested either when stationary or whilerotated by means of a lathe or rollers.3.5 To ensure complete coverage of the bore surface, thesearch unit shall be indexed approximately 75
10、% of thetransducer width with each pass of the search unit.3.6 A frequency of 214 MHz shall be used unless additionaltransducer frequencies are specified by the purchaser.3.7 The bore hole diameter and calibration hole(s) shall beas specified on the purchasers drawing or order.4. Pulsed Ultrasonic R
11、eflection Equipment andAccessories4.1 Electronic ApparatusA pulse echo instrument permit-ting inspection frequencies of 1, 2.25, and 5 MHz is required.The accuracy of discontinuity amplitude analysis using thispractice involves a knowledge of the true operating frequencyof the complete inspection sy
12、stem. One of the best ways toobtain the desired accuracy is by use of a tuned pulser andnarrow band amplifier of known frequency response, witheither a broad band transducer or a narrow band tunedtransducer of known and matching frequency. An equipmentcalibration plan that is acceptable to both the
13、purchaser and thesupplier shall be available.4.2 AmplifierThe amplifier and the cathode ray tube shallprovide linear response (within 65%)upto112 in. (38.1 mm)sweep to peak.An equipment calibration plan that is acceptableto both the purchaser and the supplier shall be available.4.3 Signal Attenuator
14、The instrument shall contain a cali-brated gain control or signal attenuator (accurate within 65%in each case) that will allow indications beyond the linear rangeof the instrument to be measured. It is recommended that thesecontrols permit signal adjustment up to 25 to 1 (28 dB).4.4 Search UnitsDual
15、 longitudinal wave search units ofknown effective frequency should be used for scanning. Each14- by 1-in. (6.35 by 25.4-mm) 2.25 MHz transducer, used withthe 1-in. dimension parallel to the longitudinal axis of theforging, will provide a desirable combination of resolution and1This practice is under
16、 the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved May 1, 2012. Published May 2012. Originallyapproved in 1995. Last previous edition approved in 2007 as A93
17、9 07. DOI:10.1520/A0939-07R12.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.beam width. Search units shall have interchangeable plexiglassshoes that are machined to various diameters for matchingdifferent bore diameters.5. Preparat
18、ion of Forging for Ultrasonic Inspection5.1 The surface of the bore shall be free of tool tears, loosescale, grinding particles, or other foreign material at the time ofultrasonic testing.5.2 Bore surfaces should be honed for bore diameter uni-formity to maintain a near constant energy transmission
19、fromthe transducer into the forging.6. Procedure6.1 Establish the inspection sensitivity such that the reflec-tion amplitude equals 100 % of the screen height throughoutthe entire inspection, using the calibration hole, specified bythe purchaser, drilled parallel to the bore surface.6.2 Check the di
20、stance calibration for linearity.6.3 Using only one transducer connected with pulse delay,mark the location of the reflected signal from the curvedsurface of the plexiglass shoe as the bore surface.6.4 Record the distance from the bore surface to the side ofthe calibration hole.6.5 Adjust the sweep
21、length control to position the backreflection approximately three fourths of the distance across thecathode ray tube.6.6 Record all indications axially and circumferentially as apercentage of the calibration hole sensitivity.6.7 Support the search unit with structural means at regularintervals.6.8 R
22、ecord all indications for radial distance and axialdistance.7. Report7.1 Report the following information:7.1.1 Amplitudes of all indications as a percentage of thecalibration hole sensitivity,7.1.2 Axial locations of all indications,7.1.3 Radial and circumferential locations of all indications,7.1.
23、4 Areas with high densities of indications as levels of5 % increments, and7.1.5 All reflection losses of 20 % or more.8. Keywords8.1 bore inspection; bored turbine rotor; forgings; ultrasonicexaminationASTM International takes no position respecting the validity of any patent rights asserted in conn
24、ection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the respons
25、ible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful c
26、onsideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 10
27、0 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).A939 07 (2012)2
