1、Designation:A275/A275M15Standard Practice forMagnetic Particle Examination of Steel Forgings1This standard is issued under the fixed designation A275/A275M;the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of last revision.A n
2、umber in parentheses indicates the year of last reapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 This practice2covers a procedure for magnetic particl
3、eexamination of steel forgings.The procedure will produceconsistent results upon which acceptance standards can bebased.This practice does not contain acceptance standards orrecommended quality levels.1.2 Only direct current or rectified alternating(full or halfwave)current shall be used as the elec
4、tric power source for anyof the magnetizing methods.Alternating current is not permit-ted because its capability to detect subsurface discontinuities isvery limited and therefore unsuitable.1.2.1 Portable battery powered electromagnetic yokes areoutside the scope of this practice.NOTE1Guide E709 may
5、 be utilized for magnetic particle examinationin the field for machinery components originally manufactured from steelforgings.1.3 The minimum requirements for magnetic particle ex-amination shall conform to practice standards of PracticeE1444/E1444M.If the requirements of this practice are inconfli
6、ct with the requirements of Practice E1444/E1444M,therequirements of this practice shall prevail.1.4 This practice and the applicable material specificationsare expressed in both inch-pound units and SI units.However,unless the order specifies the applicable“M”specificationdesignation SI units,the m
7、aterial shall be furnished toinch-pound units.1.5 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two
8、systems may result in non-conformancewith the standard.1.6 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
9、 regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:3A508/A508M Specification for Quenched and TemperedVacuum-Treated Carbon and Alloy Steel Forgings forPressure VesselsA788/A788M Specification for Steel Forgings,General Re-quirementsE709 Guide for Magnetic Particle Testing
10、E1444/E1444M Practice for Magnetic Particle Testing2.2 Other Document:Recommended Practice No.SNT-TC-1A,SupplementB-Magnetic Particle Method43.Terminology3.1 Definitions:3.1.1 indicationthe visual magnetic particle buildup re-sulting from leakage fields in the magnetic field.3.1.2 linear indicationa
11、n indication in which the length isat least three times the width.The minimum length ofindications to be considered linear shall be116in.1.6 mm.3.1.3 magnetic fluxthe product of the magnetic inductionand the area of a surface(or cross section)when the magneticinduction is uniformly distributed and n
12、ormal to the plane ofthe surface.The concept that the magnetic field is flowingalong the lines of force suggests that these lines are therefore“flux”lines,and they are called magnetic flux.3.1.4 magnetic particle method of examinationa methodfor detecting discontinuities on or near the surface in su
13、itably1This 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 1944.Last previous editio
14、n approved in 2013 as A275/A275M 08(2013).DOI:10.1520/A0275_A0275M-15.2For ASME Boiler and Pressure Vessel Code applications see related MethodSA-275/SA-275M in Section II of that Code.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.o
15、rg.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.4Available 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 t
16、he end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 magnetized materials,which employs finely divided magneticparticles that tend to congregate in regions of leakage fields.3.1.5 nonrelevant indicationsindications produced byleakage fields.However,the conditions causing them arepresent by design or accident,or other features of the parthaving no relation to the damaging flaws being sought.Theterm signifies that such
