1、Designation: A341/A341M 16Standard Test Method forDirect Current Magnetic Properties of Soft MagneticMaterials Using D-C Permeameters and the Point by Point(Ballistic) Test Methods1This standard is issued under the fixed designation A341/A341M; the number immediately following the designation indica
2、tes 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.This standard has been approved for use by agencies of t
3、he U.S. Department of Defense.1. Scope1.1 This test method provides dc permeameter tests for thebasic magnetic properties of soft magnetic materials in theform of bars, rods, wire, or strip specimens which may be cut,machined, or ground from cast, compacted, sintered, forged,extruded, rolled, or oth
4、er fabricated materials. It includes testsfor determination of the normal induction under symmetricallycyclically magnetized (SCM) conditions and the hysteresisloop (B-H loop) taken under conditions of rapidly changing orsteep wavefront reversals of the direct current magnetic fieldstrength. This me
5、thod has been historically referred to as theballistic test method. For testing hard or permanent magnetmaterials, Test Method A977/A977M shall be used.1.2 This test method shall be used in conjunction withPractice A34/A34M.1.3 This test method covers a range of magnetic fieldstrength in the specime
6、n from about 0.05 Oe 4 A/m up toabove 5000 Oe 400 kA/m through the use of severalpermeameters. The separate permeameters cover this testregion in several overlapping ranges.1.4 Normal induction and hysteresis properties may bedetermined over the magnetic flux density range from essen-tially zero to
7、the saturation induction for most materials.1.5 Recommendations of the useful magnetic field strengthrange for each of the permeameters are shown in Table 1.2Permeameters particularly well suited for general testing ofsoft magnetic materials are shown in boldface. Also, seeSections 3 and 4 for gener
8、al limitations relative to the use ofpermeameters.1.6 The symbols and abbreviated definitions used in this testmethod appear with Fig. 1 and in appropriate sections of thisdocument. For the official definitions, see Terminology A340.Note that the term magnetic flux density used in this documentis sy
9、nonymous with the term magnetic induction.1.7 WarningMercury has been designated by EPA andmany state agencies as a hazardous material that can causecentral nervous system, kidney, and liver damage. Mercury, orits vapor, may be hazardous to health and corrosive tomaterials. Caution should be taken w
10、hen handling mercury andmercury-containing products. See the applicable product Ma-terial Safety Data Sheet (MSDS) for details and EPAs website(http:/www.epa.gov/mercury/faq.htm ) for additional informa-tion. Users should be aware that selling mercury or mercury-containing products, or both, in your
11、 state may be prohibited bystate law.1.8 The values and equations stated in customary (cgs-emuand inch-pound) or SI units are to be regarded separately asstandard. Within this standard, SI units are shown in bracketsexcept for the sections concerning calculations where there areseparate sections for
12、 the respective unit systems. The valuesstated in each system may not be exact equivalents; therefore,each system shall be used independently of the other. Combin-ing values from the two systems may result in nonconformancewith this standard.1.9 This standard does not purport to address all of thesa
13、fety 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:3A34/A34M Practice for Sampling
14、 and Procurement Testing1This test method is under the jurisdiction of ASTM Committee A06 onMagnetic Properties and is the direct responsibility of Subcommittee A06.01 on TestMethods.Current edition approved May 1, 2016. Published May 2016. Originallyapproved in 1969. Last previous edition approved
15、in 2011 as A341/A341M 00(2011)1. DOI: 10.1520/A0341_A0341M-16.2The boldface numbers in parentheses refer to a list of references at the end ofthis standard.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AST
16、MStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1of Magnetic MaterialsA340 Terminology of Symbols and Definitions Relating toMagnetic Testin
17、gA596/A596M Test Method for Direct-Current MagneticProperties of Materials Using the Ballistic Method andRing SpecimensA977/A977M Test Method for Magnetic Properties of High-Coercivity Permanent Magnet Materials Using Hyster-esigraphs2.2 IEC Standard:Publication 60404-4, Ed. 2.2 Magnetic Materials P
18、art 4:Methods of Measurement of D.C. Magnetic Properties ofTABLE 1 PermeametersPermeameterUseful Magnetic Field Strength RangeAH MeasuringDeviceBReluctanceCompensationMagnetizing CoilSurroundsSpecimenReferencesDOe kA/mBabbit 40/1000 3.2/80 I, HC yes yes (1,2)Burroughs 0.1/300 0.008/24 I yes yes (1,3
19、,4,5)Fahy SimplexC0.1/300 0.008/24 HC no no (1,4,5,6,7)Fahy SimplexSuper H adapterC100/2500 8/200 HC no no (1,3)Full range 0.05/1400 0.004/112 HC yes yes (1,8)High H 100/5000 8/400 FC yes no (1,5,7,9)Iliovici 0.5/500 0.04/400 I, HC yes yes (4,10,11)IEC Type A 0.1/2500 0.008/200 HC, HP no yes IEC 604
20、04-4IEC Type B 0.1/630 0.008/50 RCC no no IEC 60404-4Isthmus 100/20 000+ 8/1600+ HC, HP no no (1,4,12,13)MH 0.1/300 0.008/24 FC yes yes (1,6,14)NPL 0.5/2500 0.04/200 I, HC yes yes (15)Saturation 100/4000 8/320 HC no yes (5,16,17)AAlthough the permeameters are capable of being used at the lower end o
21、f the measurement range, the measurement accuracy is reduced.BImagnetizing current; HCfixed H coil; FCflip coil; HPHall probe; RCC Rogowski-Chattock coil.CFahy permeameters require a standard of known magnetic properties for calibration of the H coil.DThe boldface numbers in parentheses refer to a l
22、ist of references at the end of this standard.NOTE 1A1Multirange ammeter (main current)A2Multirange ammeter (hysteresis current)BMagnetic flux density test position for Switch S3FElectronic FluxmeterHMagnetic field strength test position for Switch S3N1Magnetizing coilN2Magnetic flux sensing (B) coi
23、lN3Magnetic field strength (H) sensing coilR1Main current control rheostatR2Hysteresis current control rheostatS1Reversing switch for magnetizing currentS2Shunting switch for hysteresis current control rheostatS3Fluxmeter selector switchSPSpecimenFIG. 1 Basic Circuit Using PermeameterA341/A341M 162I
24、ron and Steel, IEC, 1995 PlusAmendments 1 in 2000 and2 in 200842.3 Other Documents:NIST Circular No. 74, pg. 2695NIST Scientific Paper 117, SPBTA53. Significance and Use3.1 Permeameters require the use of yokes to complete themagnetic circuit and are therefore inherently less accurate thanring test
25、methods. Refer to Test Method A596/A596M forfurther details on ring test methods. However, when testingcertain shapes as bars or when magnetic field strength in excessof 200 Oe 16 kA/m is required, permeameters are the onlypractical means of measuring magnetic properties.3.2 This test method is suit
26、able for specification acceptance,service evaluation, research and development and design.3.3 When the test specimen is fabricated from a largersample and is in the same condition as the larger sample, it maynot exhibit magnetic properties representative of the originalsample. In such instances the
27、test results, when viewed incontext of past performance history, will be useful for judgingthe suitability of the material for the intended application.4. Interferences4.1 In general, permeameters do not maintain a uniformmagnetic field in either the axial or radial directions around thetest specime
28、n. The field gradients in both of these directionswill differ in the various permeameters.Also the H-sensing andB-sensing coils of the different permeameters are not identicalin area, in turns, or in length or identically located. Althoughtest specimens are prepared to have uniform physical crosssec
29、tion, they may have undetected nonuniform magnetic prop-erties radially or axially along the specimen length adjacent tothe H or B coils. Some permeameters may also introduceclamping strains into the test specimen. For the above reasonstest results obtained on a test specimen with one type per-meame
30、ter may not agree closely with those obtained on thesame test specimen using another type of permeameter.5. Apparatus5.1 Because of the differences in physical construction ofthe various permeameters listed in Table 1, no standard list ofcomponents is given. When used with a particular type ofpermea
31、meter, the components should conform to the generalrequirements listed below.Abasic schematic of a permeameteris shown in Fig. 1.5.2 PermeameterThe particular permeameter used shallbe of high quality construction. The yokes should be made ofhigh permeability alloy such as oriented or nonoriented sil
32、iconiron or nickel-iron alloy, although low carbon steel or iron isacceptable in certain instances. The preferred yoke dimensionsare listed in the appended references (see Table 1). Deviationsfrom these dimensions should be such that the yoke isoperating at or below the point of maximum permeability
33、 forthe highest test magnetic flux densities encountered. Yokeconstruction may consist of either stacked laminations orstripwound C cores suitably bolted or adhesive bonded to-gether.5.3 Power SupplyThe magnetizing current shall be sup-plied by either storage batteries or dc power supplies. Linearpo
34、wer supplies have been found to be well suited for this use.The source of dc current must be stable, have negligible rippleand be capable of quickly returning to the stable state afterswitching. When programmable power supplies are used,either digital or analog programming signals are permissiblepro
35、vided that equal but opposite polarity current cycling ispossible.5.4 Main-Current-Control Rheostats, R1When used, theserheostats must have sufficient power rating and heat-dissipatingcapacity to handle the voltage and largest test current and mustprovide sufficient resistance to limit the test curr
36、ents to thoserequired for the lowest magnetic field strength to be used.5.5 Hysteresis-Current-Control Rheostats, R2When used,these rheostats must have the same characteristics as themain-current control rheostats.5.6 Main-Current Ammeter, A1Magnetizing current mea-surement shall be conducted using
37、a digital ammeter orcombination of a digital voltmeter and precision currentsensing resistor with an overall accuracy of better than 0.25 %when the magnetic field strength will be determined from thecurrent. In those permeameters where the magnetic fieldstrength is determined by other means, such as
38、 Hall probes orH coils, lower accuracy analog instruments can be used. Insuch permeameters, the ammeter is used to prevent excessivecurrents from being applied and, based on past experience, toroughly establish the required magnetic field strength.5.7 Hysteresis-Current Ammeter, A2The requirements o
39、f5.6 shall apply. In general, a separate ammeter is not required.5.8 Reversing Switch, S1When nonprogrammable dc cur-rent sources such as storage batteries are used, a currentreversing switch is required. The reversing switch should beeither a high quality knife switch, mechanical or electricalsolen
40、oid-operated contractors or mercury switches having highcurrent rating and the ability to maintain uniform contactresistance of equal magnitude in both current directions.Switches with contact bounce or other multiple contactingbehavior on make or break must be avoided. Because of thepresence of lea
41、kage currents in the open condition, solid staterelays are not permitted.5.9 Hysteresis Switch, S2This single pole switch mustconform to the same requirements as the reversing Switch, S1.5.10 Fluxmeter, FBecause of their superior accuracy,stability, and ease of operation, electronic fluxmeters shall
42、 beused to measure the magnetic flux density and, if an H-coil isused, the magnetic field strength. Fluxmeters using eitheroperational amplifier and capacitor feedback (analog integra-tor) or analog to digital conversion and digital integration arepermitted. The accuracy of the fluxmeter must be bet
43、ter than4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.5Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.A341/A341M 1631 % full scale. If analog
44、display meters are used to read thevalue of magnetic flux, the measurement should be made onthe upper two-thirds of the scale.Analog fluxmeters must havedrift adjust circuitry and the drift should not exceed 100maxwell-turns 106Wb-turns per minute on the most sensi-tive range. It is also desirable t
45、hat the fluxmeter have appro-priate scaling circuitry to permit direct reading of eithermagnetic flux () or magnetic flux density (B).5.11 B CoilsPrewound fixed magnetic flux sensing coilsare often used. When used, the cross-sectional area enclosed bythe secondary winding and number of turns must ea
46、ch beknown to within 0.5 %.5.12 Magnetic Field Strength Measuring DevicesCertainpermeameters do not or cannot use the magnetizing current todetermine the magnetic field strength accurately. Such per-meameters instead use stationary H coils, flip coils, or Hallprobes. When such devices are used, they
47、 shall be capable ofdetermining the magnetic field strength to accuracy of 1.0 % orbetter.6. Test Specimens6.1 Test specimen area shall normally be determined frommass, length, and density as indicated in 9.1 and 10.1. Whenthe test specimen is machined or ground to have a very smoothsurface, the phy
48、sical dimensions obtained from micrometermeasurements may be used to calculate the cross-sectionalarea.6.2 Test specimens in bar form may be of round, square, orrectangular cross-sectional shape. In some permeameters thebar specimen may be a half round or any shape having auniform cross-sectional ar
49、ea. Certain permeameters must havea good magnetic joint between the ends of the test specimenand the permeameter yoke or pole faces. Pole shoes may benecessary to create this joint. Generally, to achieve a goodmagnetic joint, the test specimen must be of square orrectangular cross section and must be machined or ground tohave straight and parallel surfaces. For permeameters usingspecimens butted to pole pieces, the specimen ends must besmooth and parallel.6.3 When the material is in flat-rolled form and is to beevaluated as half tran
