Standard Guide for Magnetic Particle Testing1 - UNLP

1 Designation: E709 08 Standard Guide forMagnetic Particle Testing1 This Standard is issued under the fixed designation E709; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, 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 Standard has been approved for use by agencies of the Department of This guide2describes techniques for both dry and wetmagnetic Particle testing, a nondestructive method for detect-ing cracks and other discontinuities at or near the surface inferromagnetic materials. Magnetic Particle testing may beapplied to raw material, semifinished material (billets, blooms,castings, and forgings), finished material and welds, regardlessof heat treatment or lack thereof.

2 It is useful for preventivemaintenance This Guide is intended as a reference to aid in thepreparation of specifications/standards, procedures and This Guide is also a reference that may be used To establish a means by which Magnetic particletesting, procedures recommended or required by individualorganizations, can be reviewed to evaluate their applicabilityand To aid in the organization of the facilities and person-nel concerned in Magnetic Particle To aid in the preparation of procedures dealing withthe examination of materials and parts. This Guide describesmagnetic Particle testing techniques that are recommended fora great variety of sizes and shapes of ferromagnetic materialsand widely varying examination requirements. Since there aremany acceptable differences in both procedure and technique,the explicit requirements should be covered by a writtenprocedure (see Section21).

3 This Guide does not indicate, suggest, or specify accep-tance standards for parts/pieces examined by these should be pointed out, however, that after indications havebeen produced, they must be interpreted or classified and thenevaluated. For this purpose there should be a separate code,specification, or a specific agreement to define the type, size,location, degree of alignment and spacing, area concentration,and orientation of indications that are unacceptable in a specificpart versus those which need not be removed before partacceptance. Conditions where rework or repair is not permittedshould be This Guide describes the use of the following magneticparticle method Dry Magnetic powder ( ), Wet Magnetic Particle ( ), Magnetic slurry/paint Magnetic Particle ( ), Polymer Magnetic Particle ( ).

4 Qualification Personnel performing exami-nations in accordance with this Guide should be qualified andcertified in accordance with ASNT Recommended Practice , ANSI/ASNT StandardCP-189,NAS 410,orasspecified in the contract or purchase Testing Agency If a nondestructivetesting agency as described in PracticeE543is used to performthe examination, the nondestructive testing agency should meetthe requirements of The numerical values shown in inch-pound units are tobe regarded as the Standard . SI units are provided for informa-tion 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 Referenced Standards:3A275/A275 MPractice for Magnetic Particle Examinationof Steel ForgingsA456/A456 MSpecification for Magnetic Particle Examina-tion of Large Crankshaft ForgingsD93 Test Methods for Flash Point by Pensky-MartensClosed Cup TesterD445 Test Method for Kinematic Viscosity of Transparent1 This Guide is under the jurisdiction of ASTM CommitteeE07on Nondestruc-tive Testing and is the direct responsibility of LiquidPenetrant and Magnetic Particle edition approved Feb.

5 15, 2008. Published April 2008. Originallyapproved in 1980. Last previous edition approved in 2001 as E709 - 01. ASME Boiler and Pressure Vessel Code Applications see related GuideSE-709 in Section II of that referenced ASTM standards, visit the ASTM website, , orcontact ASTM Customer Service at ForAnnual Book of ASTMS tandardsvolume information, refer to the Standard s Document Summary page onthe ASTM ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United Opaque Liquids (and Calculation of Dynamic Viscos-ity)E165 Practice for Liquid Penetrant Examination for GeneralIndustryE543 Specification for Agencies Performing Nondestruc-tive TestingE1316 Terminology for Nondestructive ExaminationsE1444 Practice for Magnetic Particle TestingE2297 Guide for Use of UV-A and Visible Light Sourcesand Meters used in the Liquid Penetrant and MagneticParticle of automotive Engineers (SAE): AerospaceMaterials Specifications.

6 4 AMS 2300 Premium Aircraft Quality Steel CleanlinessMagnetic Particle Inspection ProcedureAMS 2301 Aircraft Quality Steel Cleanliness Magnetic Par-ticle Inspection ProcedureAMS 2303 Aircraft Quality Steel Cleanliness MartensiticCorrosion Resistant Steels Magnetic Particle InspectionProcedureAMS 2641 Vehicle Magnetic Particle InspectionAMS 3040 Magnetic Particles, Non-fluorescent, DryMethodAMS 3041 Magnetic Particles, Non-fluorescent, WetMethod, Oil Vehicle, Ready to UseAMS 3042 Magnetic Particles, Non-fluorescent, WetMethod, Dry PowderAMS 3043 Magnetic Particles, Non-fluorescent, Oil Ve-hicle, Aerosol PackagedAMS 3044 Magnetic Particles, Fluorescent, Wet Method,Dry PowderAMS 3045 Magnetic Particles, Non-fluorescent, WetMethod, Oil Vehicle, Ready to UseAMS 3046 Magnetic Particles, Non-fluorescent, WetMethod, Oil Vehicle, Aerosol PackagedAMS 5062 Steel, Low Carbon Bars, Forgings, Tubing,Sheet, Strip, and Plate Carbon, MaximumAMS 5355 Investment CastingsAMS-I-83387 Inspection Process, Magnetic RubberAS 4792 Water Conditioning Agents for Aqueous MagneticParticle InspectionAS 5282 Tool Steel Ring Standard for Magnetic ParticleInspectionAS 5371 Reference Standards Notched Shims for MagneticParticle society for Nondestructive Testing:5 SNT-TC-1 APersonnel Qualification and Certification inNondestructive TestingCP-189 ASNT Qualification and Certification of Nonde-structive Testing Standards:6A-A-59230 Fluid, Magnetic Particle Inspection, SuspensionFED-STD 313 Material Safety Data Sheets Preparation andthe Submission Hazard Documents.

7 8 NAS 410 Nondestructive Testing Personnel Qualificationand Certification3. For definitions of terms used in the practice, refer toTerminologyE13164. Summary of The Magnetic Particle method is based onestablishing a Magnetic field with high flux density in aferromagnetic material. The flux lines must spread out whenthey pass through non-ferromagnetic material such as air in adiscontinuity or an inclusion. Because flux lines can not cross,this spreading action may force some of the flux lines out of thematerial (flux leakage). Flux leakage is also caused by reduc-tion in ferromagnetic material (cross-sectional change), a sharpdimensional change, or the end of the part. If the flux leakageis strong enough, fine Magnetic particles will be held in placeand an accumulation of particles will be visible under theproper lighting conditions.

8 While there are variations in themagnetic Particle method, they all are dependent on thisprinciple, that Magnetic particles will be retained at thelocations of Magnetic flux leakage. The amount of flux leakageat discontinuities depends primarily on the following factors;flux density in the material, and size, orientation, and proximityto the surface of a discontinuity. With longitudinal fields, all ofthe flux lines must complete their loops though air and anexcessively strong Magnetic field may interfere with examina-tion near the flux entry and exit points due to the highflux-density present at these While this practice permits and describesmany variables in equipment, materials, and procedures, thereare three steps essential to the The part must be Magnetic particles of the type designated in thecontract/purchase order/specification should be applied whilethe part is magnetized or immediately Any accumulation of Magnetic particles must beobserved, interpreted.

9 And to Magnetize A ferromagnetic material can bemagnetized either by passing an electric current through thematerial or by placing the material within a Magnetic fieldoriginated by an external source. The entire mass or a portionof the mass can be magnetized as dictated by size andequipment capacity or need. As previously noted, in order to bedetectable, the discontinuity must interrupt the normal path ofthe Magnetic field lines. If a discontinuity is open to the4 Available from society of automotive Engineers (SAE), 400 CommonwealthDr., Warrendale, PA 15096-0001, from American society for Nondestructive Testing (ASNT), Box28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, from Occupational Safety and Health Administration (OSHA), 200 Constitution Ave.

10 , NW, Washington, DC 20210, from Aerospace Industries Association of America, Inc. (AIA), 1000 Wilson Blvd., Suite 1700, Arlington, VA 22209-3928, 082surface, the flux leakage attracting the particles will be at themaximum value for that particular discontinuity. When thatsame discontinuity is below the surface, flux leakage evidenton the surface will be a lesser Direction If a discontinuity is oriented parallelto the Magnetic field lines, it may be essentially , since discontinuities may occur in any orientation, itmay be necessary to magnetize the part or the area of interesttwice or more sequentially in different directions by the samemethod or a combination of different methods (see Section13)to induce Magnetic field lines in a suitable direction in whichto perform an adequate Strength The Magnetic field must be of suffi-cient strength to indicate those discontinuities which areunacceptable, yet must not be so strong that an excess of localparticle accumulation masks relevant indications (see Section14).