1、Designation: A341/A341M 00 (Reapproved 2011)Standard Test Method forDirect Current Magnetic Properties of Materials Using D-CPermeameters and the Ballistic Test Methods1This standard is issued under the fixed designation A341/A341M; the number immediately following the designation indicates the year
2、of 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 the Departmen
3、t of Defense.1. Scope1.1 This test method provides dc permeameter tests for thebasic magnetic properties of materials in the form of bars, rods,wire, or strip specimens which may be cut, machined, orground from cast, compacted, sintered, forged, extruded,rolled, or other fabricated materials. It inc
4、ludes tests fordetermination 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.1.2 This test method shall be used in c
5、onjunction withPractice A34/A34M.1.3 This test method covers a range of magnetic fieldstrength in the specimen 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 inducti
6、on and hysteresis properties may bedetermined over the flux density range from essentially zero tointrinsic saturation for most materials.1.5 Recommendations of the useful magnetic field strengthrange for each of the permeameters are shown in Table 12.Also, see Sections 3 and 4 for general limitatio
7、ns relative to theuse of permeameters.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 flux density used in this document issynonymous with the ter
8、m 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 when handling mercury
9、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 state may be prohibit
10、ed 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 the respective unit sys
11、tems. 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 thesafety concerns, if any, a
12、ssociated 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 and Procurement Testing
13、of Magnetic MaterialsA340 Terminology of Symbols and Definitions Relating toMagnetic TestingA596/A596M Test Method for Direct-Current MagneticProperties of Materials Using the Ballistic Method andRing Specimens2.2 IEC Standard:Publication 60404-4, Ed. 2.0 Magnetic Materials Part 4:Methods of Measure
14、ment of D.C. Magnetic Properties ofIron and Steel, IEC, 199541This test method is under the jurisdiction of ASTM Committee A06 onMagnetic Properties and is the direct responsibility of SubcommitteeA06.01 on TestMethods.Current edition approved Oct. 1, 2011. Published October 2011. Originallyapproved
15、 in 1969. Last previous edition approved in 2005 as A341/A341M 00(2005)1. DOI: 10.1520/A0341_A0341M-00R11.2The 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 Servic
16、e at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive,
17、PO Box C700, West Conshohocken, PA 19428-2959, United States.2.3 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 me
18、thods. 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 15.9 or more kA/m are required, permeameters arethe only practical means of measuring magnetic properties.3.2 This test metho
19、d is suitable 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 insta
20、nces the 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 thetes
21、t specimen. 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
22、 crosssection, 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
23、per-meameter 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
24、 ofpermeameter, 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 nonori
25、ented siliconiron or nickel-iron alloy, although low carbon steel or iron isacceptable in certain instances. The preferred yolk dimensionsare listed in the appended references (see Table 1). Deviationsfrom these dimensions should be such that the yolk is operating5Available from National Institute o
26、f Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.TABLE 1 PermeametersPermeameterUseful Magnetic Field Strength RangeAH MeasuringDeviceBReluctanceCompensationMagnetizing CoilSurroundsSpecimenReferences2Oe kA/mBabbit 40/1000 3.2/80 I, HC yes
27、yes (1,2)Burroughs 0.1/300 0.008/24 I yes yes (1,3,4,5)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)I
28、EC Type A 0.1/2500 0.008/200 HC, HP no yes IEC 60404-4IEC 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 permeam
29、eters are capable of being used at the lower end of the measurement range, the measurement accuracy is reduced.BImagnetizing current; HCfixed H coil; FCflip coil; HPHall probe; RCCRogowski-Chattock coil.CFahy permeameters require a standard of known magnetic properties for calibration of the H coil.
30、NOTE 1A1Multirange ammeter (main current)A2Multirange ammeter (hysteresis current)BFlux density test position for Switch S3FElectronic IntegratorHMagnetic field strength test position for Switch S3N1Magnetizing coilN2Flux sensing (B) coilN3Magnetic field strength sensing coilR1Main current control r
31、heostatR2Hysteresis current control rheostatS1Reversing switch for magnetizing currentS2Shunting switch for hysteresis current control rheostatS3Integrator selector switchSPSpecimenFIG. 1 Basic Circuit Using PermeameterA341/A341M 00 (2011)2at or below the point of maximum permeability for the highes
32、ttest flux densities encountered. Yoke construction may consistof either stacked laminations or stripwound C cores suitablybolted or adhesive bonded together.5.3 Power SupplyThe magnetizing current shall be sup-plied by either storage batteries or dc power supplies. Bipolarprogrammable linear power
33、supplies have been found to bewell suited for this use.The source of dc current must be stable,have negligible ripple and be capable of quickly returning tothe stable state after switching. When programmable powersupplies are used, either digital or analog programming signalsare permissible provided
34、 that equal but opposite polaritycurrent cycling is possible.5.4 Main-Current-Control Rheostats, R1When used,these rheostats must have sufficient power rating and heat-dissipating capacity to handle the voltage and largest testcurrent and must contain sufficient resistance to limit the testcurrents
35、to those required for the lowest magnetic field strengthto 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 a dig
36、ital ammeter orcombination of a digital voltmeter and precision shunt resistorwith an overall accuracy of better than 0.25 % when themagnetic field strength will be determined from the current. Inthose permeameters where the magnetic field strength isdetermined by other means, such as Hall probes or
37、 H coils,lower accuracy analog instruments can be used. In suchpermeameters, 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 of5.6 shall appl
38、y. 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 electricalsolenoid-operated co
39、ntractors 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 leakage currents i
40、n 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 Integrator, FBecause of their superior accuracy,stability, and ease of operation, electronic charge integratorsare the pref
41、erred means of measuring magnetic flux. Integra-tors using either operational amplifier and capacitor feedback(analog integrator) or pulse counting are permitted. The accu-racy of the integrator must be better than 1 % full scale. Ifanalog display meters are used to read the value of flux, themeasur
42、ement should be made on the upper two-thirds of thescale. Analog integrators must have drift adjust circuitry andthe drift should not exceed 100 Maxwell-turns 106Wb-turnsper minute on the most sensitive range. It is also desirable thatthe integrator have appropriate scaling circuitry to permit direc
43、treading of either flux (f) or flux density (B). Ballistic galva-nometers or moving coil fluxmeters are permitted provided the1 % full-scale accuracy requirement is met. Such devicesrequire additional circuitry not shown in Fig. 1. Details may befound in the appropriate references appended to this t
44、estmethod.5.11 B CoilsPrewound fixed flux sensing coils are oftenused. When used, the cross-sectional area enclosed by thesecondary winding and number of turns must be known to bebetter than 0.5 %.5.12 Magnetic Field Strength Measuring DevicesCertainpermeameters do not or cannot use the magnetizing
45、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 shall be capable ofdetermining the apparent magnetic field strength to accuracy of1.0 % or better.6. Test Specimens6.1 Test speci
46、men 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 physical dimensions obtained from micrometermeasurements may be used to calculate the cross-sectionalarea.6.2 Test specimens
47、 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 area. Certain permeameters must havea good magnetic joint between the ends of the test specimenand the permeameter yoke or
48、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 sp
49、ecimen ends must besmooth and parallel.6.3 When the material is in flat-rolled form and is to beevaluated as half transverse-half longitudinal, the specimenshall be sheared to have strips in multiples of four in accor-dance with Table 2. When material is to be evaluated in onedirection, it shall conform to this table or to the requirementsfor best test quality in a particular permeameter. For gages No.33 and thinner, the cross-sectional area shall be not less than0.31 in.2200 mm2 and not more than 0.62 in.2400 mm2.6.4 When the test
