1、Designation: A939 07 (Reapproved 2012) A939/A939M 12Standard Practice forUltrasonic Examination from Bored Surfaces of CylindricalForgings1This standard is issued under the fixed designation A939;A939/A939M; the number immediately following the designation indicates theyear of original adoption or,
2、in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope Scope*1.1 This practice covers a basic procedure of ultrasonically inspecting cylind
3、rical forgings with bores 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. (63.5 mm).64
4、mm.1.4 This practice is expressed 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 sta
5、ndard. The values given in parentheses are mathematical conversions to SI units that areprovided for information only and are not considered stated in each system may not be exact equivalents; therefore, each systemshall be used independently of the other. Combining values from the two systems may r
6、esult 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 the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulator
7、ylimitations prior to use.2. Referenced Documents2.1 ASNT Standard:2SNT-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 specifi
8、cation forinspection purposes in which the acceptance of the forging is 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 prac
9、tice specifies dual search units, requires pitch-catch search unit with twin transducers, which depending on theangle, are sensitive only to 2 to 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 ultras
10、onic inspection. It may be impossible to inspect somesmall portions of the bore surface because of chamfers at stepdownsstep-downs and other local configurations.4.2 The bore ultrasonic inspection shall be performed after the final austenitizing and tempering heat treatment for mechanicalproperties
11、of the forging, and may be performed either prior to or after any subsequent stress relieving heat treatment.4.3 The ultrasonic beam shall be introduced radially for overall scanning.4.4 Forgings may be tested either when stationary or while rotated by means of a lathe or rollers.1 This practice is
12、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 May 1, 2012Nov. 1, 2012. Published May 2012November 2012. Originally approved in 1995. Last previous
13、 edition approved in 20072012 asA939 07.A939 07 (2012). DOI: 10.1520/A0939-07R12.10.1520/A0939_A0939M-12.2 Available from American Society for Nondestructive 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 i
14、ntended 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 the cu
15、rrent 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 States14.5 To ensure complete covera
16、ge 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 MHz shall be used unless additional transducer frequencies are specified by the purchaser.4.7 The bore hole diameter and calibration hole
17、(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 certified in accordance with a writtenprocedure conforming to SNT-TC-1A or another national standard that is acceptable to both the purchas
18、er and the supplier.6. Pulsed Ultrasonic Reflection Equipment and Accessories6.1 Electronic ApparatusA pulse echo instrument permitting inspection frequencies of 1, 2.25, and 5 MHz is required. Theaccuracy of discontinuity amplitude analysis using this practice involves a knowledge of the true opera
19、ting 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 broad band transducer or a narrow band tuned transducer of known andmatching frequency. An equipment ca
20、libration plan that is acceptable to both the purchaser and the supplier shall be available.6.2 AmplifierThe amplifier and the cathode ray tube instrument screen shall provide linear response (within 65 %) up to 112in. (38.1 mm)38 mm sweep to peak. An equipment calibration plan that is acceptable to
21、 both the purchaser and the supplier shallbe available.6.3 Signal AttenuatorThe instrument Instruments shall contain a calibrated gain control or signal attenuator (accurate within65 % in each case) that will allow indications beyond the linear range of the instrument to be measured. It is recommend
22、ed thatthese controls permit signal adjustment up to 25 to 1 (28 dB).6.4 Search UnitsDualPitch-catch longitudinal wave search units of known effective frequency should be used for scanning.Each unit, containing twin 14- by 1-in. (6.35 by 25.4-mm) 2.25 MHz transducer, 6 by 24-mm 2.0 or 2.25 MHz trans
23、ducers, shallbe used with the 1-in. 25 mm dimension parallel to the longitudinal axis of the forging, willto provide a desirable combinationof resolution and beam width. Search units shall have interchangeable plexiglass shoes that are machined to various diameters formatching different bore diamete
24、rs.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. testing and shall have a surface finish of 63 in. 1.08 m or better.7.2 Bore surfaces should be h
25、oned 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 amplitude equals 100 % of the screen height throughout the entireinspection, using the calibration hole,
26、 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,delay; mark the location of the reflected signal from the curvedsurface of the plexiglass shoe asat the bore surface.8.4 Record
27、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 the cathoderay tube. instrument screen.8.6 Record all indications axially and circumferentially as a percentag
28、e 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 Amplitudes of all indications as a percentage of the calibration hole sen
29、sitivity,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.A939/A939M 12210. Keywords10.1 bore inspection; bored turbine rot
30、or; forgings; ultrasonic examinationSUMMARY OF CHANGESCommittee A01 has identified the location of selected changes to this standard since the last issue (A939 07(2012) that may impact the use of this standard. (Approved Nov. 1, 2012.)(1) Changed to dual unit practice.(2) Clarified transducer detail
31、s and replaced term “cathode ray tube.”(3) Added bore surface finish and personnel requirements.ASTM International takes no 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 determin
32、ation 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 responsible technical committee and must be reviewed every five years andif not revised, either reapproved or wit
33、hdrawn. 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 consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that yo
34、ur 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, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (sin
35、gle 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/A939M 123
