ASTM A341/A341M-16(2022)
(Test Method)Standard Test Method for Direct Current Magnetic Properties of Soft Magnetic Materials Using D-C Permeameters and the Point by Point (Ballistic) Test Methods
Standard Test Method for Direct Current Magnetic Properties of Soft Magnetic Materials Using D-C Permeameters and the Point by Point (Ballistic) Test Methods
SIGNIFICANCE AND USE
3.1 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 [16 kA/m] is required, permeameters are the only practical means of measuring magnetic properties.
3.2 This test method is suitable for specification acceptance, service evaluation, research and development and design.
3.3 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 soft magnetic 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. This method has been historically referred to as the ballistic test method. For testing hard or permanent magnet materials, Test Method A977/A977M shall be used.
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 magnetic flux density range from essentially zero to the saturation induction for most materials.
1.5 Recommendations of the useful magnetic field strength range for each of the permeameters are shown in Table 1.2 Permeameters particularly well suited for general testing of soft magnetic materials are shown in boldface. 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 magnetic flux density used in this document is synonymous with the term magnetic induction.
FIG. 1 Basic Circuit Using Permeameter
Note 1:
A1—Multirange ammeter (main current)
A2—Multirange ammeter (hysteresis current)
B—Magnetic flux density test position for Switch S3
F—Electronic Fluxmeter
H—Magnetic field strength test position for Switch S3
N1—Magnetizing coil
N2—Magnetic flux sensing (B) coil
N3—Magnetic field strength (H) sensing coil
R1—Main current control rheostat
R2—Hysteresis current control rheostat
S1—Reversing switch for magnetizing current
S2—Shunting switch for hysteresis current control rheostat
S3—Fluxmeter selector switch
SP—Specimen
1.7 Warning—Mercury 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 p...
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: A341/A341M − 16 (Reapproved 2022)
Standard Test Method for
Direct Current Magnetic Properties of Soft Magnetic
Materials Using D-C Permeameters and the Point by Point
1
(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.
1. Scope 1.6 Thesymbolsandabbreviateddefinitionsusedinthistest
method appear with Fig. 1 and in appropriate sections of this
1.1 This test method provides dc permeameter tests for the
document. For the official definitions, see Terminology A340.
basic magnetic properties of soft magnetic materials in the
Notethatthetermmagneticfluxdensityusedinthisdocument
form of bars, rods, wire, or strip specimens which may be cut,
is synonymous with the term magnetic induction.
machined, or ground from cast, compacted, sintered, forged,
extruded, rolled, or other fabricated materials. It includes tests
1.7 Warning—Mercury has been designated by EPA and
fordeterminationofthenormalinductionundersymmetrically
many state agencies as a hazardous material that can cause
cyclically magnetized (SCM) conditions and the hysteresis
central nervous system, kidney, and liver damage. Mercury, or
loop (B-H loop) taken under conditions of rapidly changing or
its vapor, may be hazardous to health and corrosive to
steep wavefront reversals of the direct current magnetic field
materials.Cautionshouldbetakenwhenhandlingmercuryand
strength. This method has been historically referred to as the
mercury-containing products. See the applicable product Ma-
ballistic test method. For testing hard or permanent magnet
terial Safety Data Sheet (MSDS) for details and EPA’s website
materials, Test Method A977/A977M shall be used.
(http://www.epa.gov/mercury/faq.htm)foradditionalinforma-
1.2 This test method shall be used in conjunction with
tion. Users should be aware that selling mercury or mercury-
Practice A34/A34M.
containingproducts,orboth,inyourstatemaybeprohibitedby
state law.
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
1.8 The values and equations stated in customary (cgs-emu
above 5000 Oe [400 kA/m] through the use of several
and inch-pound) or SI units are to be regarded separately as
permeameters. The separate permeameters cover this test
standard. Within this standard, SI units are shown in brackets
region in several overlapping ranges.
except for the sections concerning calculations where there are
1.4 Normal induction and hysteresis properties may be
separate sections for the respective unit systems. The values
determined over the magnetic flux density range from essen-
stated in each system may not be exact equivalents; therefore,
tially zero to the saturation induction for most materials.
each system shall be used independently of the other. Combin-
ingvaluesfromthetwosystemsmayresultinnonconformance
1.5 Recommendations of the useful magnetic field strength
2
with this standard.
range for each of the permeameters are shown in Table 1.
Permeameters particularly well suited for general testing of
1.9 This standard does not purport to address all of the
soft magnetic materials are shown in boldface. Also, see
safety concerns, if any, associated with its use. It is the
Sections 3 and 4 for general limitations relative to the use of
responsibility of the user of this standard to establish appro-
permeameters.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1
This test method is under the jurisdiction of ASTM Committee A06 on
1.10 This international standard was developed in accor-
MagneticPropertiesandisthedirectresponsibilityofSubcommitteeA06.01onTest
dance with internationally recognized principles on standard-
Methods.
Current edition approved Oct. 1, 2022. Published October 2022. Originally
ization established in the Decision on Principles for the
approved in 1969. Last previous edition approved in 2016 as A341/A341M–16.
Development of International Standards, Guides and Recom-
DOI: 10.1520/A0341_A0341M-16R22.
2 mendations issued by the World Trade Organization Technical
The boldface numbers in parentheses refer to a list of references at the end of
this standard. Barriers to Trade (TBT) Committee.
Copyright © ASTM International, 100 Barr Harb
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