1、Designation: E2905/E2905M 12Standard Practice forExamination of Mill and Kiln Girth Gear TeethElectromagnetic Methods1This standard is issued under the fixed designation E2905/E2905M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision,
2、 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. Scope1.1 This practice describes a two-part procedure for electro-magnetic evaluation on gear teeth on mill and ki
3、ln gear drivesand pinions. The first part of this practice details the ability todetect 100 % of surface-breaking discontinuities only in theaddendum, dedendum, and root area of the gear tooth. Thesecond part of the examination is to have the ability to measureaccurately the length and depth of any
4、cracks found in theseareas. No existing practice addresses the use of eddy currentarray for the detection of surface-breaking discontinuities onmill and kiln gear teeth combined with alternating current fieldmeasurement to size accurately any cracks found, length anddepth.1.2 This practice is used o
5、nly for crack detection and earlysigns of macro-pitting. It will not illustrate a full gear toothanalysis. Visual examination by an experienced gear technicianis the only way to analyze fully gear teeth wear patterns andpotential failure.1.3 Two technicians are required for this practice. Onetechnic
6、al assistant guides the probe and the other technicianoperates the computer/software and analyzes the gear teethcondition.1.4 It is important that Practice E2261 and Guides E709accompany the technician when performing the examination.1.5 It is recommended that the technician reviews theappendixes in
7、 this practice well in advance of starting the job.1.6 A clean gear is recommended for a complete gearanalysis. Depending on the lubrication used, the technician, indiscussion with the client, shall determine what cleaningprocedure should be used. If a non-asphaltic lubricant is used,ensure the gear
8、 teeth surface is clean. If an asphaltic-basedlubricant is used, refer to the annexes and appendixes in thispractice.1.7 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard. Thevalues stated in each system may not be exact equivalents;therefore, ea
9、ch system shall be used independently of the other.Combining values from the two systems may result in noncon-formance with the standard.1.8 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 e
10、stablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E709 Guide for Magnetic Particle TestingE1316 Terminology for Nondestructive ExaminationsE2261 Practice for Examination of Welds Using
11、the Alter-nating Current Field Measurement Technique2.2 AIA Standard:3NAS 410 Certification and Qualification of NondestructiveTest Personnel2.3 ANSI/AGMA Standards:4ANSI/AGMA 1010 E-95 Standard for Appearance of GearTeethTerminology of Wear and FailureANSI/AGMA 1012 G-05 Gear Nomenclature, Definiti
12、on ofTerms2.4 ANSI/ASNT Standards:4ANSI/ASNT-CP-189 Qualification and Certification of Non-destructive Testing PersonnelSNT-TC-1A Recommended Practice Personnel Qualifica-tion and Certification in Nondestructive Testing3. Terminology3.1 DefinitionsThe definitions of general terms relating togear exa
13、minations can be found in Guide E709, TerminologyE1316, Practice E2261, ANSI/AGMA 1012 G-05, and ANSI/AGMA 1010 E-95.1This test method is under the jurisdiction of ASTM Committee E07 onNondestructive Testing and is the direct responsibility of Subcommittee E07.07 onElectromagnetic Method.Current edi
14、tion approved Nov. 15, 2012. Published November 2012. DOI:10.1520/E2905_E2905M-12.2For 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 pag
15、e onthe ASTM website.3Available from Aerospace Industries Association of America, Inc. (AIA), 1000Wilson Blvd., Suite 1700,Arlington, VA22209-3928, http:/www.aia-aerospace.org.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.o
16、rg.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2 Eddy Current Array Method:3.2.1 basic concepts of eddy current array, ECA, neddycurrent array (ECA) technology provides the ability to driveelectronically multiple eddy current co
17、ils placed side by side inthe same probe assembly. Data acquisition is performed bymultiplexing the eddy current coils in a special pattern to avoidmutual inductance between the individual coils. Most conven-tional eddy current flaw detection techniques can be repro-duced with an ECA examination. Wi
18、th the benefits of single-pass coverage, and enhanced imaging capabilities, ECAtechnology provides a remarkably powerful tool and significanttime savings during inspections. (See Fig. 1.)3.2.1.1 DiscussionThe use of eddy current array is forcrack detection and early signs of macro-pitting only.Limit
19、ationseddy current array will not reveal alignmentissues, backlash problems, lubrication issues, tip to rootinterface, and so forth. Visual interpretation is the method usedto analyze gear teeth condition. It is also very important thatthe technician has an education in gear analysis. Simple eddycur
20、rent experience does not provide the knowledge required tointerpret gear teeth issues or the understanding of ECA. Theknowledge of the defect type helps in determining the rootcauses and the potential solutions, resulting in a higherstandard of examination.3.2.2 depth of penetration, neddy current d
21、ensity does notremain constant across the depth of a material. The density isgreatest at the surface and decreases exponentially with depth(the “skin effect”). The standard depth of penetration equationis used to explain the penetration capability of eddy currenttesting, which decreases with increas
22、ing frequency,conductivity, or permeability. For a material that is both thickand uniform, the standard depth of penetration is the depth atwhich the eddy current density is 37 % of the material surfacevalue. To detect very shallow defects in a material, very highfrequencies are used.3.2.3 eddy curr
23、ent array probes, nprobes can be designedto detect a specific type of discontinuity and to conform to theshape of the part under examination (see Fig. 2).3.2.3.1 DiscussionProbes can be designed to detect aspecific type of discontinuity and conform to the shape of thegear tooth under examination.Als
24、o notice that the center of theroot would actually be scanned twice. In this examination,there is no saturation performed. Surface probes are made withcoils designed to be driven at relatively high frequencies(typically 50 to 500 kHz). Using higher frequencies results inless penetration of the eddy
25、current field into the test partallowing full coverage of any surface-breaking discontinuitiesof the component to be examined. In addition, the higherfrequencies provide a higher resolution for the detection ofsmaller defects. For this practice, a surface array probe, withthe ability of detecting al
26、l surface discontinuitiesincludingcracks, is required for a successful examination.3.2.4 reference standard, nshall contain at least one longreference indicator to standardize all the channels of the arrayat once and also representative defects for flaws characteriza-tion during the examination.3.2.
27、5 set screws, nconformable and substantially noncon-ducting set screws on the probe that are used to allow smallliftoff adjustments or excursions on surface response.3.2.6 system performance verification, nuse of a measure-ment of one or more physical property values for a referencepart to confirm t
28、hat the property values are within specifiedtolerances to validate the system standardization and verifyproper instrument operation.3.2.6.1 DiscussionProbe qualityProbe life varies de-pending on the environmental conditions within the work area.Some of these environmental factors are temperature, mo
29、isture,cleanliness, and the main factor being surface roughness.3.2.6.2 DiscussionDifferent equipment manufacturersmay use slightly different terminology. Reference should bemade to the equipment manufacturers documentation forclarification.3.2.7 Practice E2261The terminology, procedure, anddefiniti
30、on of terms are used in this practice.NOTE 1Different equipment manufacturers may use slightly differentterminology. Reference should be made to the equipment manufacturersdocumentation for clarification.3.3 ANSI/AGMA 1012 G-05The terminology used inANSI/AGMA 1012 G-05 is used throughout this practi
31、ce.3.4 ANSI/AGMA 1010 E-95The terminology used inANSI/AGMA 1010 E-95 is used throughout this practice.4. Summary of Practice4.1 Gear-Cleaning ProcedureTypically, operations doesthe cleaning or supervises the cleaning. Maintenance removesthe guards for access to the gear. Nondestructive evaluation(ND
32、E) girth gear examinations are provided for maintenance.As visual interpretation is the method used to analyze gearteeth condition, such as contact patterns and wear patterns, acleaned gear is mandatory. Another reason for a cleaned geartooth is that it is very hard for the ECA probe to maintain the
33、geometry of a gear tooth that is covered with lubrication,especially if the lubrication is asphaltic based. If asphalticlubrication is used, refer to Appendix X2 for cleaning proce-dures.4.1.1 ECAECA is used for nondestructively locating andcharacterizing surface-breaking discontinuities in conducti
34、ngmaterials to electrically conductive materials. For use in thispractice, the properly designed ECAprobe has proven to detectall surface-breaking discontinuities from 0.76 mm (0.03 in.)and larger on the addendum, dedendum, and root of girth gearFIG. 1 Eddy Current Single-Probe Coil Compared to Eddy
35、 CurrentArray Probe CoilsE2905/E2905M 122teeth. The examination is performed by scanning a conform-able eddy-current sensor array over the surface of theaddendum, dedendum, and root of the gear tooth beingexamined in one pass. The drive side of the tooth is referred toas the A side and the nondrive
36、side of the tooth is referred to asthe B side of the tooth. The measured responses and locationinformation are then used, typically in the form of a displayedimage (C-scan), to determine the presence and characteristicsof discontinuities.4.1.2 Alternating Current Field Measurement MethodAlternating
37、current field measurement is only to be used if acrack is found.4.1.3 Alternating Current Field Measurement for Nonde-structive Testing Detection and Sizing of Surface-BreakingCracksIt works on all metals, ferrous or nonferrous.Asensorprobe is placed on the surface to be examined and analternating c
38、urrent is induced into the surface. When no defectsare present the alternating current produces a uniform magneticFIG. 2 Coverage of a Flexible ProbeRoot, Dedendum, and AddendumFIG. 3 Two Cracks on Tooth Just Above the RootFIG. 4 Two- and Three-Dimensional ViewE2905/E2905M 123field above the surface
39、. Any defect present will perturb thecurrent, forcing it to flow around and underneath the defect;this causes the magnetic field to become non-uniform andsensors in the alternating current field measurement probemeasure these field variations. Two components of this mag-netic field are measuredone p
40、rovides information about thedepth or aspect ratio of the defect(s) and the other shows thepositions of the defects ends. The two signals are used toconfirm the presence of a defect and, together with a sizingalgorithm, measure its length and depth. The main advantageof alternating current field mea
41、surement for this practice is itprovides both depth and length information. Defects up to 25mm (1 in.) in depth can be sized accurately.4.1.4 Magnetic Particle ExaminationMagnetic particle isused when a crack is found. It is used to illustrate the crack forthe picture in the report. (See Fig. 3.) It
42、 is also used whenlift-off prevents the probe from receiving a signal.5. Significance and Use5.1 Visual interpretation of gear teeth condition is differentfrom examining for cracks or early signs of macro-pitting.Visual interpretation is referred to ANSI/AGMA 1010 E-95.5.1.1 The purpose of using edd
43、y-current array for girth gearteeth examination is it drastically reduces examination time;covers a large area in one single pass; provides real-timecartography of the examined region, facilitating data interpre-tation; and improves reliability and probability of detection(POD). One tooth can be exa
44、mined in less than 30 seconds.NOTE 2ECA is used as a discontinuity finding tool (see Fig. 3) and apresentation aid as support once problems are discovered and photo-graphed. As presentation is everything and so is visualization, colors andthree-dimensional (3D) images (see Fig. 4) that help with vis
45、ualization areabsolutely invaluable in such circumstances.5.1.2 The purpose of using alternating current field mea-surement is its ability to size accurately surface-breakingcracks.5.1.3 This practice is a useful tool for a condition-basedmonitoring program.5.2 The examination results may then be us
46、ed by qualifiedpersonnel or organizations to assess remaining service life orother engineering characteristics (beyond the scope of thispractice). This practice is not intended for the examination ofnon-surface-breaking discontinuities.6. Basis of Application6.1 The following item is subject to cont
47、ractual agreementbetween the parties using or referencing this practice.6.1.1 Personnel QualificationIf specified in the contrac-tual agreement, personnel performing examinations to thispractice shall be qualified in accordance with a nationally orinternationally recognized NDT personnel qualificati
48、on prac-tice or standard such as ANSI/ASNT-CP-189, SNT-TC-1A,NAS-410, or a similar document and certified by the employeror certifying agency, as applicable. The practice or standardused and its applicable revision shall be identified in thecontractual agreement between the using parties.7. Interfer
49、encesECA7.1 Curvature of Examination SurfaceFor helical gearswith a helix angle of 1 or more, a flexible probe is requiredand needs to be flexible enough to adjust its curvature to thevarious helix angles. System performance verification testsshould be run to verify liftoff sensitivity by adjusting the setscrews in the face of the array probe.7.2 Surface ConditionsMicropitting, macropitting,spalling, and so forth of gear teeth surfaces can be easilyscanned with the ECA probe by adjusting the set screwsallowing for liftoff. Gear teeth surfaces s
