1、Designation: A939/A939M 12A939/A939M 15Standard Practice forUltrasonic Examination from Bored Surfaces of CylindricalForgings1This standard is issued under the fixed designation A939/A939M; the number immediately following the designation indicates the yearof original adoption or, in the case of rev
2、ision, 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 a basic procedure of ultrasonically inspecting cylindrical forgings with bore
3、s from the bore surface.1.2 This practice applies to the manual testing mode. It does not restrict the use of other testing modes, such as mechanized orautomated.1.3 This practice applies to cylindrical forgings having bore sizes equal to or greater than 2.5 in. 64 mm.1.4 This practice is expressed
4、in inch-pound and SI units; however, the inch-pound units shall apply unless the purchase orderor contract specifies the applicable “M” specification designation (SI units). The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated in each s
5、ystem may not be exact equivalents; therefore, each systemshall be used independently of the other. Combining values from the two systems may result in non-conformance 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 t
6、he responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A788/A788M Specification for Steel Forgings, General Requirements2.2 ASNT Standard:3SNT-
7、TC-1A Recommended Practice for Non-destructive Personnel Qualifications and Certification3. Significance and Use3.1 This practice shall be used when ultrasonic inspection from the bore surface is required by the order or specification forinspection purposes in which the acceptance of the forging is
8、based on limitations of the number, amplitude, or location ofdiscontinuities or a combination thereof, which leads to ultrasonic indications.3.2 The acceptance criteria shall be stated clearly as order requirements.3.3 This practice requires pitch-catch search unit with twin transducers, which depen
9、ding on the angle, are sensitive only to 2to 3 in. 50 to 75 mm into the metal from the bore surface.4. General Requirements4.1 As far as possible, the entire bore surface shall be subjected to ultrasonic inspection. It may be impossible to inspect somesmall portions of the bore surface because of ch
10、amfers at step-downs and other local configurations.4.2 The bore ultrasonic inspection shall be performed after the final austenitizing and tempering heat treatment for mechanicalproperties of the forging, and may be performed either prior to or after any subsequent stress relieving heat treatment.4
11、.3 The ultrasonic beam shall be introduced radially for overall scanning.1 This practice is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.06on Steel Forgings and Billets.Current edition approved Nov. 1,
12、2012May 1, 2015. Published November 2012May 2015. Originally approved in 1995. Last previous edition approved in 2012 asA939 07 (2012).A939/A939M 12. DOI: 10.1520/A0939_A0939M-12.10.1520/A0939_A0939M-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Serv
13、ice at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.This docu
14、ment 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 technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as
15、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 standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United
16、 States14.4 Forgings may be tested either when stationary or while rotated by means of a lathe or rollers.4.5 To ensure complete coverage of the bore surface, the search unit shall be indexed approximately 75 % of the transducerwidth with each pass of the search unit.4.6 A frequency of 2.0 or 214 MH
17、z shall be used unless additional transducer frequencies are specified by the purchaser.4.7 The bore hole diameter and calibration hole(s) shall be as specified on the purchasers drawing or order.5. Personnel5.1 Personnel performing ultrasonic examination to this practice shall be qualified and cert
18、ified in accordance with a writtenprocedure conforming to SNT-TC-1A or another national standard that is acceptable to both the purchaser and the supplier.6. Pulsed Ultrasonic Reflection Equipment and Accessories6.1 Electronic ApparatusA pulse echo instrument permitting inspection frequencies of 1,
19、2.25, and 5 MHz is required. Theaccuracy of discontinuity amplitude analysis using this practice involves 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 freq
20、uency response, with either a broad band transducer or a narrow band tuned transducer of known andmatching frequency. An equipment calibration plan that is acceptable to both the purchaser and the supplier shall be available.6.2 AmplifierThe amplifier and the instrument screen shall provide linear r
21、esponse (within 65 %) up to 112 in. 38 mmsweep to peak. An equipment calibration plan that is acceptable to both the purchaser and the supplier shall be available.6.3 Signal AttenuatorInstruments shall contain a calibrated gain control or signal attenuator (accurate within 65 % in eachcase) that wil
22、l allow indications beyond the linear range of the instrument to be measured. It is recommended that these controlspermit signal adjustment up to 25 to 1 (28 dB).6.4 Search UnitsPitch-catch longitudinal wave search units of known effective frequency should be used for scanning. Eachunit, containing
23、twin 14- by 1-in. 6 by 24-mm 2.0 or 2.25 MHz transducers, shall be used with the 1-in. 25 mm dimensionparallel to the longitudinal axis of the forging, to provide a desirable combination of resolution and beam width. Search units shallhave interchangeable shoes that are machined to various diameters
24、 for matching different bore diameters.7. Preparation of Forging for Ultrasonic Inspection7.1 The surface of the bore shall be free of tool tears, loose scale, grinding particles, or other foreign material at the time ofultrasonic testing and shall have a surface finish of 63 in. 1.08 m or better. T
25、he definition for surface finish shall be as perSpecification A788/A788M.7.2 Bore surfaces should be honed for bore diameter uniformity to maintain a near constant energy transmission from thetransducer into the forging.8. Procedure8.1 Establish the inspection sensitivity such that the reflection am
26、plitude equals 100 % of the screen height throughout the entireinspection, using the calibration hole, specified by the purchaser, drilled parallel to the bore surface.8.2 Check the distance calibration for linearity.8.3 Using only one transducer connected with pulse delay; mark the location of the
27、reflected signal from the curved surface ofthe shoe at the bore surface.8.4 Record the distance from the bore surface to the side of the calibration hole.8.5 Adjust the sweep length control to position the back reflection approximately three fourths of the distance across theinstrument screen.8.6 Re
28、cord all indications axially and circumferentially as a percentage of the calibration hole sensitivity.8.7 Support the search unit with structural means at regular intervals.8.8 Record all indications for radial distance and axial distance.9. Report9.1 Report the following information:9.1.1 Amplitud
29、es of all indications as a percentage of the calibration hole sensitivity,9.1.2 Axial locations of all indications,9.1.3 Radial and circumferential locations of all indications,9.1.4 Areas with high densities of indications as levels of 5 % increments, and9.1.5 All reflection losses of 20 % or more.
30、A939/A939M 15210. Keywords10.1 bore inspection; bored turbine rotor; forgings; ultrasonic examinationSUMMARY OF CHANGESCommittee A01 has identified the location of selected changes to this standard since the last issue (A939 07(2012)A939/A939M 12) that may impact the use of this standard. (Approved
31、Nov. 1, 2012May 1, 2015.)(1) Changed to dual unit practice.(2) Clarified transducer details and replaced term “cathode ray tube.”(1) Added boreSpecification A788/A788M as a Referenced Document, and revised 7.1 relative surface finish and personnelrequirements.requirement.ASTM International takes no
32、position respecting the validity of any patent rights asserted in connection 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 responsi
33、bility.This standard is subject to revision at any time by the responsible 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
34、ASTM International Headquarters. Your comments will receive careful consideration 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 addre
35、ss shown below.This standard is copyrighted by ASTM International, 100 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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 153
