ASTM_A_939_-_A_939M_-_15.pdf

Designation:A939/A939M15Standard 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 revision,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 ultrasonicallyinspecting cylindrical forgings with bores from the 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.64 mm.1.4 This practice is expressed in inch-pound and SI units;however,the inch-pound units shall apply unless the purchaseorder or contract specifies the applicable“M”specificationdesignation(SI units).The values stated in either SI units orinch-pound units are to be regarded separately as standard.Thevalues stated in each system may not be exact equivalents;therefore,each system shall 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 thesafety concerns,if any,associated with its use.It is theresponsibility 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.Referenced Documents2.1 ASTM Standards:2A788/A788M Specification for Steel Forgings,General Re-quirements2.2 ASNT Standard:3SNT-TC-1A Recommended Practice for Non-destructivePersonnel Qualifications and Certification3.Significance and Use3.1 This practice shall be used when ultrasonic inspectionfrom the bore surface is required by the order or specificationfor 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.3.2 The acceptance criteria shall be stated clearly as orderrequirements.3.3 This practice requires pitch-catch search unit with twintransducers,which depending on the angle,are sensitive onlyto 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 besubjected to ultrasonic inspection.It may be impossible toinspect some small portions of the bore surface because ofchamfers at step-downs and other local configurations.4.2 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 stress relieving heat treatment.4.3 The ultrasonic beam shall be introduced radially foroverall scanning.4.4 Forgings may be tested either when stationary or whilerotated by means of a lathe or rollers.4.5 To ensure complete coverage of the bore surface,thesearch unit shall be indexed approximately 75%of thetransducer width with each pass of the search unit.4.6 A frequency of 2.0 or 214MHz shall be used unlessadditional transducer frequencies are specified by the pur-chaser.4.7 The bore hole diameter and calibration hole(s)shall beas specified on the purchasers drawing or order.5.Personnel5.1 Personnel performing ultrasonic examination to thispractice shall be qualified and certified in accordance with a1This practice is under 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 1,2015.Published May 2015.Originallyapproved in 1995.Last previous edition approved in 2012 as A939/A939M 12.DOI:10.1520/A0939_A0939M-15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available fromAmerican Society for Nondestructive Testing(ASNT),P.O.Box28518,1711 Arlingate Ln.,Columbus,OH 43228-0518,http:/www.asnt.org.*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 States1 written procedure conforming to SNT-TC-1A or another na-tional standard that is acceptable to both the purchaser and thesupplier.6.Pulsed Ultrasonic Reflection Equipment andAccessories6.1 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 knowledge of the true operating frequency ofthe complete inspection system.One of the best ways t