ASTM A340-19

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
Designation:A340 −19
Standard Terminology of
1
Symbols and Definitions Relating to Magnetic Testing
This standard is issued under the fixed designation A340; the number immediately following the designation indicates the year 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.
INTRODUCTION
In preparing this terminology standard, an attempt has been made to avoid, where possible, vector
analysisanddifferentialequationssoastomakethedefinitionsmoreintelligibletotheaverageworker
in the field of magnetic testing. In some cases, rigorous treatment has been sacrificed to secure
simplicity and clarity, but it is believed that none of the definitions will prove to be misleading.
It is the intent of this terminology standard to be consistent in the use of symbols and units with
those found in IEC 60050-221:1990 International ElectrotechnicalVocabulary Chapter 221: Magnetic
materials and components. Although Committee A06 has chosen to make SI units normative, the
extensive technical and commercial literature using the older Gaussian units requires that many
definitions contain discussion about and use of both unit systems. This is not an endorsement of the
older unit system and users of this terminology are encouraged to use SI units where possible.
1
This terminology is under the jurisdiction of ASTM Committee A06 on
Magnetic Properties and is the direct responsibility of Subcommittee A06.92 on
Terminology and Definitions.
Current edition approved Feb. 15, 2019. Published March 2019. Originally
approved in 1949. Last previous edition approved in 2018 as A340 – 18. DOI:
10.1520/A0340-19.
Part 1—Symbols Used in Magnetic Testing
Symbol Term df distortion factor
D magnetic dissipation factor
m
α cross-sectional area of B coil E exciting voltage
A cross-sectional area of specimen E induced primary voltage
1
A' solid area E induced secondary voltage
2
B E flux volts
f
magnetic flux density
f cyclic frequency in hertz
H
magnetic induction
^ magnetomotive force
ff form factor
∆B excursion range of induction H magnetic field strength
∆H excursion range of magnetic field strength
B · biased induction
b
B remanent induction H biasing magnetic field strength
d b
B remanence H coercive field strength
dm cB
H intrinsic coercive field strength
B H energy product
d d cJ
(BH) maximum energy product H demagnetizing field strength
d
max
H incremental magnetic field strength
B incremental induction
∆ ∆
B intrinsic flux density H air gap magnetic field strength
g
i
H ac magnetic field strength (from an assumed
B maximum induction in a hysteresis loop
m L
B maximum induction in a flux current loop peak value of magnetizing current)
max
H maximum magnetic field strength in a hyster-
B residual induction
r m
B retentivity esis loop
rs
H maximum magnetic field strength in a flux-
B saturation flux density
max
s
current loop
cf crest factor
CM cyclically magnetized condition H ac magnetic field strength (from a measured
p
peak value of exciting current)
d lamination thickness
D demagnetizing coefficient
B
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
A340−19
H instantaneous magnetic field strength (coinci- 5 reluctance
t
dent with B ) R core resistance
max 1
H ac magnetic field strength (from an assumed R winding resistance
z w
peak value of exciting current) S lamination factor (stacking factor)
I ac exciting current (rms value)
SCM symmetrically cyclically magnetized condition
I ac core loss current (rms value) T Curie temperature
c
c
I constant current w lamination width
dc
I ac magnetizing current (rms value) W hysteresis loop loss
m h
J magnetic polarization linear expansion, coefficient (average)
α¯
J saturation magnetic polarization
∆χ incremental tolerance
s
k' coupling coefficient
β hysteretic angle
! flux path length
γ loss angle
! effective flux path length
1 cos γ magnetic power factor
! gap length
g γ proton gyromagnetic ratio
p
+ (also φ N ) flux linkage
µ magnetic constant
0
+ mutual flux linkage
m δ density
L self inductance
κ susceptibility
L core inductance
1 ac Permeabilities:
L incremental inductance
µ ideal permeability
∆
a
L intrinsic inductance
i µ inductance permeability
L
L mutual inductance
m µ L incremental inductance permeability
∆
L initial inductance
0 µ initial dynamic permeability
0d
L series inductance
s µ peak permeability
p
L winding inductance
µ incremental peak permeability
w
∆p
m magnetic moment
µ instantaneous permeability
i
M magnetization
µ impedance permeability
z
M saturation magnetization
s µ incremental impedance permeability
∆z
m total mass of a specimen
dc Pe
...