1、Designation: A340 161A340 17Standard Terminology ofSymbols and Definitions Relating to Magnetic Testing1This standard is issued under the fixed designation A340; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1 NOTEEditorial corrections made throughout in May 2017.INTRODUCTIONIn preparing this glossary of terms, an attempt has been made to avoid,
3、 where possible, vectoranalysis and differential equations so as to make the definitions more intelligible to the average workerin the field of magnetic testing. In some cases, rigorous treatment has been sacrificed to securesimplicity, but it is believed that none of the definitions will prove to b
4、e misleading.It is the intent of this glossary to be consistent in the use of symbols and units with those found inANSI/IEEE 260-1978 and USA Standard Y 10.5-1968.Part 1Symbols Used in Magnetic TestingSymbol Term cross-sectional area of B coilA cross-sectional area of specimenA solid areaB Hmagnetic
5、 flux densitymagnetic inductionB excursion range of inductionBb biased inductionBd remanent inductionBdm remanenceBdHd energy product(BdHd)m maximum energy productB incremental inductionBi intrinsic inductionBm maximum induction in a hysteresis loopBmax maximum induction in a flux current loopBr res
6、idual inductionBrs retentivityBs saturation inductioncf crest factorCM cyclically magnetized conditiond lamination thicknessDB demagnetizing coefficientdf distortion factorDm magnetic dissipation factorE exciting voltageE1 induced primary voltageE2 induced secondary voltageEf flux voltsf cyclic freq
7、uency in hertz magnetomotive forceff form factorH magnetic field strengthH excursion range of magnetic field strength1 This terminology is under the jurisdiction of ASTM Committee A06 on Magnetic Properties and is the direct responsibility of Subcommittee A06.92 on Terminologyand Definitions.Current
8、 edition approved May 1, 2016July 1, 2017. Published May 2016July 2017. Originally approved in 1949. Last previous edition approved in 20152016 asA340 15.A340 161. DOI: 10.1520/A0340-16E01.10.1520/A0340-17.This document is not an ASTM standard and is intended only to provide the user of an ASTM stan
9、dard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by AST
10、M is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Hb biasing magnetic field strengthHcB coercive field strengthHcJ intrinsic coercive field strengthHd demagnetizing field strengthH incremental
11、 magnetic field strengthHg air gap magnetic field strengthHL ac magnetic field strength (from an assumedpeak value of magnetizing currentHL ac magnetic field strength (from an assumedpeak value of magnetizing current)Hm maximum magnetic field strength in a hyster-esis loopHmax maximum magnetic field
12、 strength in a flux-current loopHp ac magnetic field strength (from a measuredpeak value of exciting current)Ht instantaneous magnetic field strength (coinci-dent with Bmax)Hz ac magnetic field strength force (from an as-sumed peak value of exciting current)I ac exciting current (rms value)Ic ac cor
13、e loss current (rms value)Idc constant currentIm ac magnetizing current (rms value)J magnetic polarizationk coupling coefficient! flux path length!1 effective flux path length!g gap length+ (also N ) flux linkage+m mutual flux linkageL self inductanceL1 core inductanceL incremental inductanceLi intr
14、insic inductanceLm mutual inductanceL0 initial inductanceLs series inductanceLw winding inductancem magnetic momentM magnetizationm total mass of a specimenm1 active mass of a specimenND demagnetizing factorN1 turns in a primary windingN2 turns in a secondary windingN1I/!1 ac excitationp magnetic po
15、le strength3 permeanceP active (real) powerPa apparent powerPa (B;f) specific apparent powerPc total core lossPc (B;f) specific core lossPc incremental core lossPe normal eddy current core lossPe incremental eddy current core lossPh normal hysteresis core lossPh incremental hysteresis core lossPq re
16、active (quadrature) powerPr residual core lossPw winding loss (copper loss)Pz exciting powerPz (B;f) specific exciting powerQm magnetic storage factor5 reluctanceR1 core resistanceRw winding resistanceS lamination factor (stacking factor)SCM symmetrically cyclically magnetized conditionTc Curie temp
17、eraturew lamination widthWh hysteresis loop loss linear expansion, coefficient (average) incremental tolerance hysteretic angle loss anglecos magnetic power factorA340 172p proton gyromagnetic ratio0 magnetic constant density susceptibilityac Permeabilities:a ideal permeabilityL inductance permeabil
18、ityL incremental inductance permeability0d initial dynamic permeabilityp peak permeabilityp incremental peak permeabilityi instantaneous permeabilityz impedance permeabilityz incremental impedance permeabilitydc Permeabilities: normal permeabilityabs absolute permeabilityd differential permeability
19、incremental permeabilityeff effective circuit permeabilityi incremental intrinsic permeabilitym maximum permeabilityi initial permeabilityr relative permeabilityv space permeabilityrev reversible permeability/cot figure of merit reluctivity the numeric 3.1416 resistivity magnetic fluxN flux linkage
20、(see +) mass susceptibility0 initial susceptibility angular frequency in radians per secondPart 2Definition of Terms Used in Magnetic Testingac excitation, N1I/1the ratio of the rms ampere-turns of exciting current in the primary winding of an inductor to the effectiveflux path length of the inducto
21、r.active (real) power, Pthe product of the rms current, I, in an electrical circuit, the rms voltage, E, across the circuit, and thecosine of the angular phase difference, between the current and the voltage.P 5 EI cosDISCUSSIONThe portion of the active power that is expended in a magnetic core is t
22、he total core loss, Pc.aging coefficientthe percentage change in a specific magnetic property resulting from a specific aging treatment.DISCUSSIONThe aging treatments usually specified are:(a) 100 h at 150C or(b) 600 h at 100C.aging, magneticthe change in the magnetic properties of a material result
23、ing from metallurgic change due to a normal orspecified aging condition.DISCUSSIONThis term implies a deterioration of the magnetic properties of magnetic materials for electronic and electrical applications, unless otherwise specified.air-gap magnetic field strength, Hgthe magnetic field strength r
24、equired to produce the induction existing at some point in anonmagnetic gap in a magnetic circuit.DISCUSSIONA340 173In the cgs-emu system of units, Hg is numerically equal to the induction existing at such a point and exceeds the magnetic field strength in the magneticmaterial.amorphous alloya semip
25、rocessed alloy produced by a rapid quenching, direct casting process resulting in metals withnoncrystalline structure.ampere (turn),Athe unit of magnetomotive force in the SI system of units. The symbolArepresents the unit of electric current,ampere, in the SI system of units.ampere per metre, A/mth
26、e unit of magnetic field strength in the SI system of units.anisotropic materiala material in which the magnetic properties differ in various directions.anisotropy of lossthe ratio of the specific core loss measured with flux parallel to the rolling direction to the specific core losswith flux perpe
27、ndicular to the rolling direction.anisotropy of loss5Pc B;f! lPc B;f! twhere:Pc (B;f) l = specific core loss value with flux parallel to the rolling direction, W/lb W/kg, andPc (B;f) t = specific core loss value with flux perpendicular to the rolling direction, W/lb W/kg.DISCUSSIONThis definition of
28、 anisotropy normally applies to electrical steels with measurements made in an Epstein frame at a flux density of 15 kG 1.5 T anda frequency of 60 Hz (see Test Method A343).anisotropy of permeabilitythe ratio of relative peak permeability measured with flux parallel to the rolling direction to there
29、lative peak permeability measured with flux perpendicular to the rolling direction.anisotropy of permeability5prlprtwhere:prl = relative peak permeability value with flux parallel to the rolling direction, andprt = relative peak permeability value with flux perpendicular to the rolling direction.DIS
30、CUSSIONThis definition of anisotropy normally applies to electrical steels with measurements made in an Epstein frame at a flux density of 15 kG 1.5 T anda frequency of 60 Hz (see Test Method A343).antiferromagnetic materiala feebly magnetic material in which almost equal magnetic moments are lined
31、up antiparallel toeach other. Its susceptibility increases as the temperature is raised until a critical (Nel) temperature is reached; above thistemperature the material becomes paramagnetic.apparent power, Pathe product (volt-amperes) of the rms exciting current and the applied rms terminal voltage
32、 in an electriccircuit containing inductive impedance. The components of this impedance as a result of the winding will be linear, while thecomponents as a result of the magnetic core will be nonlinear. The unit of apparent power is the volt-ampere, VA.apparent power, specific, Pa(B;f)the value of t
33、he apparent power divided by the active mass of the specimen, that is,volt-amperes per unit mass. The values of voltage and current are those developed at a maximum value of cyclically varyinginduction B and specified frequency f.area, Athe geometric cross-sectional area of a magnetic path which is
34、perpendicular to the direction of the induction.Bloch walla domain wall in which the magnetic moment at any point is substantially parallel to the wall surface. See alsodomain wall.Bohr magnetona constant that is equal to the magnetic moment of an electron because of its spin. The value of the const
35、antis (9 274 078 1021 erg/gauss or 9 274 078 1024 J/T).cgs-emu system of unitsthe system for measuring physical quantities in which the base units are the centimetre, gram, andsecond, and the numerical value of the magnetic constant, 0, is unity.coercive field strength, HcBthe absolute value of the
36、applied magnetic field strength (H) required to restore the magnetic fluxdensity (B) to zero.A340 174DISCUSSIONThe symbol Hc has historically been used to denote the coercive field strength determined from a (B,H) loop. Further use of this symbol in ASTMA06 standards is deprecated.DISCUSSIONThe coer
37、cive field strength monotonically increases with increasing maximum magnetic field strength (Hm) reaching a maximum or limiting valuetermed the coercivity. Unless it is known that the material has been magnetized to saturation, the term coercive field strength is preferred.DISCUSSIONThe coercive fie
38、ld strength is not completely described without knowing the maximum magnetic flux density (Bm) or maximum magnetic field strength(Hm) used in the measurement.coercive field strength, intrinsic, HcJthe absolute value of the applied magnetic field strength (H) required to restore either themagnetic po
39、larization (J) or magnetization (M) to zero.DISCUSSIONThe symbol Hci has historically been used to denote the intrinsic coercive field strength determined from a (Bi,H) loop. Further use of this symbol inASTM A06 standards is deprecated.DISCUSSIONThe intrinsic coercive field strength monotonically i
40、ncreases with increasing maximum magnetic field strength (Hm) reaching a maximum or limitingvalue termed the intrinsic coercivity. Unless it is known that the material has been magnetized to saturation, the term intrinsic coercive field strengthis preferred.DISCUSSIONThe measured value of intrinsic
41、coercive field strength will be the same whether it is measured from a magnetic polarization (J,H) or a magnetization(M,H) hysteresis loop and will always be numerically larger than the coercive field strength (HcB) measured from a magnetic flux density (B,H)hysteresis loop.DISCUSSIONThe intrinsic c
42、oercive field strength is not completely described without knowing the maximum magnetic polarization, maximum magnetization ormaximum magnetic field strength (Hm) used in the measurement.coercivitysee coercive field strength.coercivity, intrinsicsee coercive field strength, intrinsic.core, laminated
43、a magnetic component constructed by stacking suitably thin pieces of magnetic material which are stamped,sheared, or milled from sheet or strip material. Individual pieces usually have an insulating surface coating to minimize eddycurrent losses in the assembled core.core, matedtwo or more magnetic
44、core segments assembled with the magnetic flux path perpendicular to the mating surface.core, powder(dust)a magnetic core comprised of small particles of electrically insulated metallic ferromagnetic material. Thesecores are characterized by low hysteresis and eddy current losses.core, tape-wounda m
45、agnetic component constructed by the spiral winding of strip material onto a suitable mandrel. The stripmaterial usually has an insulating surface coating which reduces interlaminar eddy current losses in the finished core.core loss, ac eddy current, incremental, Pethe power loss caused by eddy curr
46、ents in a magnetic material that is cyclicallymagnetized.core loss, ac eddy current, normal, Pethe power losses as a result of eddy currents in a magnetic material that is symetricallycyclically magnetized.DISCUSSIONA340 175The voltage is generally assumed to be across the parallel combination of co
47、re inductance, L1, and core resistance, R1.core loss, ac, incremental, Pcthe core loss in a magnetic material when the material is subjected simultaneously to a dc biasingmagnetizing force and an alternating magnetizing force.core loss, residual, Prthe portion of the core loss power, Pc, which is no
48、t attributed to hysteresis or eddy current losses fromclassical assumptions.core loss, ac, specific, Pc(B;f)the active power (watts) expended per unit mass of magnetic material in which there is a cyclicallyvarying induction of a specified maximum value, B, at a specified frequency, f.core loss, ac,
49、 (total), Pcthe active power (watts) expended in a magnetic circuit in which there is a cyclically alternatinginduction.DISCUSSIONMeasurements of core loss are normally made with sinusoidally alternating induction, or the results are corrected for deviations from the sinusoidalcondition.core loss densitythe active power (watts) expended in a magnetic core in which there is a cyclically varying induction of aspecified maximum valu
