ASTM A341/A341M-00(2011)e1
(Test Method)Standard Test Method for Direct Current Magnetic Properties of Materials Using D-C Permeameters and the Ballistic Test Methods
Standard Test Method for Direct Current Magnetic Properties of Materials Using D-C Permeameters and the Ballistic Test Methods
SIGNIFICANCE AND USE
Permeameters require the use of yokes to complete the magnetic circuit and are therefore inherently less accurate than ring test methods. Refer to Test Method A596/A596M for further details on ring test methods. However, when testing certain shapes as bars or when magnetic field strength in excess of 200 Oe [15.9 or more kA/m] are required, permeameters are the only practical means of measuring magnetic properties.
This test method is suitable for specification acceptance, service evaluation, research and development and design.
When the test specimen is fabricated from a larger sample and is in the same condition as the larger sample, it may not exhibit magnetic properties representative of the original sample. In such instances the test results, when viewed in context of past performance history, will be useful for judging the suitability of the material for the intended application.
SCOPE
1.1 This test method provides dc permeameter tests for the basic magnetic properties of materials in the form of bars, rods, wire, or strip specimens which may be cut, machined, or ground from cast, compacted, sintered, forged, extruded, rolled, or other fabricated materials. It includes tests for determination of the normal induction under symmetrically cyclically magnetized (SCM) conditions and the hysteresis loop (B-H loop) taken under conditions of rapidly changing or steep wavefront reversals of the direct current magnetic field strength.
1.2 This test method shall be used in conjunction with Practice A34/A34M.
1.3 This test method covers a range of magnetic field strength in the specimen from about 0.05 Oe [4 A/m] up to above 5000 Oe [400 kA/M] through the use of several permeameters. The separate permeameters cover this test region in several overlapping ranges.
1.4 Normal induction and hysteresis properties may be determined over the flux density range from essentially zero to intrinsic saturation for most materials.
1.5 Recommendations of the useful magnetic field strength range for each of the permeameters are shown in Table 1 . Also, see Sections 3 and 4 for general limitations relative to the use of permeameters.
1.6 The symbols and abbreviated definitions used in this test method appear with Fig. 1 and in appropriate sections of this document. For the official definitions, see Terminology A340. Note that the term flux density used in this document is synonymous with the term magnetic induction.
1.7 WarningMercury has been designated by EPA and many state agencies as a hazardous material that can cause central nervous system, kidney, and liver damage. Mercury, or its vapor, may be hazardous to health and corrosive to materials. Caution should be taken when handling mercury and mercury-containing products. See the applicable product Material Safety Data Sheet (MSDS) for details and EPA’s website (http://www.epa.gov/mercury/faq.htm) for additional information. Users should be aware that selling mercury or mercury-containing products, or both, in your state may be prohibited by state law.
1.8 The values and equations stated in customary cgs-emu and inch-pound or SI units are to be regarded separately as standard. Within this standard, SI units are shown in brackets except for the sections concerning calculations where there are separate sections for the respective unit systems. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with this standard.
1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
TABLE 1 Permeameters PermeameterUseful Magnetic Field Strength RangeAH Measuring
DeviceB Reluctance
...
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
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Designation: A341/A341M − 00(Reapproved 2011)
Standard Test Method for
Direct Current Magnetic Properties of Materials Using D-C
Permeameters and the Ballistic Test Methods
This standard is issued under the fixed designationA341/A341M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision.Anumber 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.
ε NOTE—Corrected text and Fig. 1 editorially in December 2011.
1. Scope 1.7 Warning—Mercury has been designated by EPA and
many state agencies as a hazardous material that can cause
1.1 This test method provides dc permeameter tests for the
central nervous system, kidney, and liver damage. Mercury, or
basicmagneticpropertiesofmaterialsintheformofbars,rods,
its vapor, may be hazardous to health and corrosive to
wire, or strip specimens which may be cut, machined, or
materials.Cautionshouldbetakenwhenhandlingmercuryand
ground from cast, compacted, sintered, forged, extruded,
mercury-containing products. See the applicable product Ma-
rolled, or other fabricated materials. It includes tests for
terial Safety Data Sheet (MSDS) for details and EPA’s website
determination of the normal induction under symmetrically
(http://www.epa.gov/mercury/faq.htm)foradditionalinforma-
cyclically magnetized (SCM) conditions and the hysteresis
tion. Users should be aware that selling mercury or mercury-
loop (B-H loop) taken under conditions of rapidly changing or
containingproducts,orboth,inyourstatemaybeprohibitedby
steep wavefront reversals of the direct current magnetic field
state law.
strength.
1.8 The values and equations stated in customary cgs-emu
1.2 This test method shall be used in conjunction with
and inch-pound or SI units are to be regarded separately as
Practice A34/A34M.
standard. Within this standard, SI units are shown in brackets
1.3 This test method covers a range of magnetic field
except for the sections concerning calculations where there are
strength in the specimen from about 0.05 Oe [4 A/m] up to
separate sections for the respective unit systems. The values
above 5000 Oe [400 kA/M] through the use of several
stated in each system may not be exact equivalents; therefore,
permeameters. The separate permeameters cover this test
each system shall be used independently of the other. Combin-
region in several overlapping ranges.
ingvaluesfromthetwosystemsmayresultinnonconformance
1.4 Normal induction and hysteresis properties may be with this standard.
determined over the flux density range from essentially zero to
1.9 This standard does not purport to address all of the
intrinsic saturation for most materials.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
1.5 Recommendations of the useful magnetic field strength
priate safety and health practices and determine the applica-
range for each of the permeameters are shown in Table 1.
bility of regulatory limitations prior to use.
Also,seeSections3and4forgenerallimitationsrelativetothe
use of permeameters.
2. Referenced Documents
1.6 Thesymbolsandabbreviateddefinitionsusedinthistest 3
2.1 ASTM Standards:
method appear with Fig. 1 and in appropriate sections of this
A34/A34MPractice for Sampling and Procurement Testing
document. For the official definitions, see Terminology A340.
of Magnetic Materials
Note that the term flux density used in this document is
A340Terminology of Symbols and Definitions Relating to
synonymous with the term magnetic induction.
Magnetic Testing
A596/A596MTest Method for Direct-Current Magnetic
This test method is under the jurisdiction of ASTM Committee A06 on
Properties of Materials Using the Ballistic Method and
MagneticPropertiesandisthedirectresponsibilityofSubcommitteeA06.01onTest
Ring Specimens
Methods.
Current edition approved Oct. 1, 2011. Published October 2011. Originally
approved in 1969. Last previous edition approved in 2005 as A341/ For referenced ASTM standards, visit the ASTM website, www.astm.org, or
ε1
A341M–00(2005) . DOI: 10.1520/A0341_A0341M-00R11E01. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
The boldface numbers in parentheses refer to a list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this standard. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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A341/A341M − 00 (2011)
TABLE 1 Permeameters
A
Magnetizing Coil
Useful Magnetic Field Strength Range
H Measuring Reluctance
D
Permeameter Surrounds References
B
Device Compensation
Oe kA/m Specimen
Babbit 40/1000 3.2/80 I, HC yes yes (1,2)
Burroughs 0.1/300 0.008/24 I yes yes (1,3,4,5)
C
Fahy Simplex 0.1/300 0.008/24 HC no no (1,4,5,6,7)
Fahy Simplex
100/2500 8/200 HC no no (1,3)
C
Super H adapter
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 60404-4
IEC Type B 0.1/630 0.008/50 RCC no no IEC 60404-4
Isthmus 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)
A
Although the permeameters are capable of being used at the lower end of the measurement range, the measurement accuracy is reduced.
B
I—magnetizing current; HC—fixed H coil; FC—flip coil; HP—Hall probe; RCC —Rogowski-Chattock coil.
C
Fahy permeameters require a standard of known magnetic properties for calibration of the H coil.
D
The boldface numbers in parentheses refer to a list of references at the end of this standard.
NOTE 1—
A —Multirange ammeter (main current)
A —Multirange ammeter (hysteresis current)
B—Flux density test position for Switch S
F—Electronic Integrator
H—Magnetic field strength test position for Switch S
N —Magnetizing coil
N —Flux sensing (B) coil
N —Magnetic field strength sensing coil
R —Main current control rheostat
R —Hysteresis current control rheostat
S —Reversing switch for magnetizing current
S —Shunting switch for hysteresis current control rheostat
S —Integrator selector switch
SP—Specimen
FIG. 1 Basic Circuit Using Permeameter
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A341/A341M − 00 (2011)
2.2 IEC Standard: acceptable in certain instances. The preferred yolk dimensions
Publication 60404-4,Ed. 2.0 Magnetic Materials – Part 4: are listed in the appended references (see Table 1). Deviations
Methods of Measurement of D.C. Magnetic Properties of fromthesedimensionsshouldbesuchthattheyolkisoperating
Iron and Steel, IEC, 1995 at or below the point of maximum permeability for the highest
test flux densities encountered. Yoke construction may consist
2.3 Other Documents:
of either stacked laminations or stripwound C cores suitably
NISTCircular No. 74, pg. 269
bolted or adhesive bonded together.
NISTScientific Paper 117, SPBTA
5.3 Power Supply—The magnetizing current shall be sup-
3. Significance and Use
plied by either storage batteries or dc power supplies. Bipolar
3.1 Permeameters require the use of yokes to complete the
programmable linear power supplies have been found to be
magnetic circuit and are therefore inherently less accurate than wellsuitedforthisuse.Thesourceofdccurrentmustbestable,
ring test methods. Refer to Test Method A596/A596M for
have negligible ripple and be capable of quickly returning to
further details on ring test methods. However, when testing the stable state after switching. When programmable power
certainshapesasbarsorwhenmagneticfieldstrengthinexcess
suppliesareused,eitherdigitaloranalogprogrammingsignals
of200Oe[15.9ormorekA/m]arerequired,permeametersare are permissible provided that equal but opposite polarity
the only practical means of measuring magnetic properties. current cycling is possible.
3.2 Thistestmethodissuitableforspecificationacceptance, 5.4 Main-Current-ControlRheostats,R —Whenused,these
service evaluation, research and development and design. rheostatsmusthavesufficientpowerratingandheat-dissipating
capacitytohandlethevoltageandlargesttestcurrentandmust
3.3 When the test specimen is fabricated from a larger
contain sufficient resistance to limit the test currents to those
sampleandisinthesameconditionasthelargersample,itmay
required for the lowest magnetic field strength to be used.
not exhibit magnetic properties representative of the original
sample. In such instances the test results, when viewed in 5.5 Hysteresis-Current-Control Rheostats, R —When used,
context of past performance history, will be useful for judging
these rheostats must have the same characteristics as the
the suitability of the material for the intended application. main-current control rheostats.
5.6 Main-Current Ammeter, A —Magnetizing current mea-
4. Interferences
surement shall be conducted using a digital ammeter or
4.1 In general, permeameters do not maintain a uniform
combination of a digital voltmeter and precision shunt resistor
magneticfieldineithertheaxialorradialdirectionsaroundthe
with an overall accuracy of better than 0.25% when the
test specimen. The field gradients in both of these directions
magnetic field strength will be determined from the current. In
willdifferinthevariouspermeameters.AlsotheH-sensingand
those permeameters where the magnetic field strength is
B-sensing coils of the different permeameters are not identical
determined by other means, such as Hall probes or H coils,
in area, in turns, or in length or identically located. Although
lower accuracy analog instruments can be used. In such
test specimens are prepared to have uniform physical cross
permeameters, the ammeter is used to prevent excessive
section, they may have undetected nonuniform magnetic prop-
currents from being applied and, based on past experience, to
erties radially or axially along the specimen length adjacent to
roughly establish the required magnetic field strength.
the H or B coils. Some permeameters may also introduce
5.7 Hysteresis-Current Ammeter, A —The requirements of
clamping strains into the test specimen. For the above reasons
5.6 shall apply. In general, a separate ammeter is not required.
test results obtained on a test specimen with one type per-
5.8 Reversing Switch, S —When nonprogrammable dc cur-
meameter may not agree closely with those obtained on the
rent sources such as storage batteries are used, a current
same test specimen using another type of permeameter.
reversing switch is required. The reversing switch should be
5. Apparatus
either a high quality knife switch, mechanical or electrical
solenoid-operatedcontractorsormercuryswitcheshavinghigh
5.1 Because of the differences in physical construction of
current rating and the ability to maintain uniform contact
the various permeameters listed in Table 1, no standard list of
resistance of equal magnitude in both current directions.
components is given. When used with a particular type of
Switches with contact bounce or other multiple contacting
permeameter, the components should conform to the general
behavior on make or break must be avoided. Because of the
requirementslistedbelow.Abasicschematicofapermeameter
presence of leakage currents in the open condition, solid state
is shown in Fig. 1.
relays are not permitted.
5.2 Permeameter—The particular permeameter used shall
5.9 Hysteresis Switch, S —This single pole switch must
be of high quality construction. The yokes should be made of 2
conform to the same requirements as the reversing Switch, S .
high permeability alloy such as oriented or nonoriented silicon
iron or nickel-iron alloy, although low carbon steel or iron is
5.10 Integrator, F—Because of their superior accuracy,
stability, and ease of operation, electronic charge integrators
are the preferred means of measuring magnetic flux. Integra-
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
tors using either operational amplifier and capacitor feedback
4th Floor, New York, NY 10036.
(analog integrator) or pulse counting are permitted. The accu-
Available from National Institute of Standards and Technology (NIST), 100
Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov. racy of the integrator must be better than 1% full scale. If
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A341/A341M − 00 (2011)
TABLE 2 Number of Test Strips
33 and thinner, the cross-sectional area shall be not less than
2 2 2 2
Nominal Thickness Gage Number of 0.31 in. [200 mm ] and not more than 0.62 in. [400 mm ].
in. mm Number Strips
6.4 When the test specimen for strip materials is to be half
0.0100 to 0.0250 0.254 to 0.635 32 to 24, incl 12
0.0280 to 0.0435 0.711 to 1.105 23 to 19, incl 8
transverse and half longitudinal, the strips shall be positioned
0.0500 and over 1.27 and over 18 and thicker 4
to be composed of alternately transverse and longitudinal
throughout the specimen and a transverse strip shall be placed
adjacent to the permeameter’s yoke or pole face.
6.5 For full testing accuracy, the length and size of the test
analog display meters are used to read the value of flux, the
specimen must meet the requirements of the permeameter
measurement should be made on the upper two-thirds of the
being used. Generally, for most permeameters, a test specimen
scale. Analog integrators must have drift adjust circuitry and
length of 10 in. [0.254 m] or more is required. Shorter
−6
thedriftshouldnotexceed100Maxwell-turns[10 Wb-turns]
specimens with some permeameters will require the use of
per minute on the most sensitive range. It is also desirable that
pole-piece extensions, and may cause a reduction in testing
theintegratorhaveappropriatescalingcircuitrytopermitdirect
accuracy. Other permeameters are designed for short speci-
reading of either flux (φ) or flux density (B). Ballistic galva-
mens without loss of testing accuracy.
nometersormovingcoilfluxmetersarepermittedprovidedthe
6.6 All test specimen forms shall be cut, machined, or
1% full-scale accuracy requirement is met. Such devices
ground to have a uniform cross-sectional area along the active
requireadditionalcircuitrynotshowninFig.1.Detailsmaybe
length of the test specimen. The cross-sectional area shall be
found in the appropriate references appended to this test
sufficiently uniform so that its nonuniformity will not materi-
method.
ally affect the accuracy of establishing and measuring flux
5.11 B Co
...
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