1、Designation:A342/A342M14Standard Test Methods forPermeability of Weakly Magnetic Materials1This standard is issued under the fixed designation A342/A342M;the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of last revision.A num
2、ber 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.Scope1.1 These test methods cover four procedures for determi-nat
3、ion of the permeability relative permeability2of materialshaving a permeability not exceeding 6.0.1.2 The test methods covered are as follows:1.2.1 Test Method 1Fluxmetric Method is suitable formaterials with permeabilities between 1.0 and 4.0.This methodpermits the user to select the magnetic field
4、 strength at whichthe permeability is to be measured.1.2.2 Test Method 2Permeability of Paramagnetic Mate-rials has been eliminated as an acceptable method of test.1.2.3 Test Method 3Low Mu Permeability Indicator issuitable for measuring the permeability of a material as“lessthan”or“greater than”tha
5、t of calibrated standard inserts withpermeability between 1.01 and 6.0,as designated for use in aLow-Mu Permeability Indicator.3In this method,a smallvolume of specimen is subjected to a local magnetic field thatvaries in magnitude and direction,so it is not possible tospecify the magnetic field str
6、ength at which the measurement ismade.1.2.4 Test Method 4Flux Distortion is suitable for mate-rials with permeability between 1.0 and 2.0.In this method,asmall volume of specimen is subjected to a local magnetic fieldthat varies in magnitude and direction,so it is not possible tospecify the magnetic
7、 field strength at which the measurement ismade.41.2.5 Test Method 5Vibrating Sample Magnetometry issuitable for materials with permeability between 1.0 and 4.0.This test method permits the user to select the magnetic fieldstrength at which the permeability is to be measured.1.3 Materials typically
8、tested by these methods such asaustenitic stainless steels may be weakly ferromagnetic.Thatis,the magnetic permeability is dependent on the magneticfield strength.As a consequence,the results obtained using thedifferent methods may not closely agree with each other.Whenusing Methods 1 and 5,it is im
9、perative to specify the magneticfield strength or range of magnetic field strengths at which thepermeabilities have been determined.1.4 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 b
10、racketsexcept for the sections concerning calculations where there areseparate sections for the respective unit systems.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 non
11、conformancewith this standard.1.5 This standard does not purport to address all of thesafety concerns,if any,associated 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 p
12、rior to use.2.Referenced Documents2.1 ASTM Standards:51These test methods are under the jurisdiction of ASTM Committee A06 onMagnetic Properties and are the direct responsibility of Subcommittee A06.01 onTest Methods.Current edition approved May 1,2014.Published May 2014.Originallyapproved in 1949.L
13、ast previous edition approved in 2012 as A342/A342M04(2012).DOI:10.1520/A0342_A0342M-14.2Test Methods 1 and 5 actually measure magnetic susceptibility.The perme-ability()relative permeability(r)is related to the susceptibility()by theequations:=1+4(cgs-emu)r=1+(SI)The term permeability has been reta
14、ined in these test methods because of itswidespread commercial and technological usage.3The sole source of supply of the apparatus known to the committee at this timeis Low-Mu Permeability Indicator,manufactured by Severn Engineering Co.,Inc.,555 Stage Rd.,Suite 1A,Auburn,AL 36830,http:/.(Indicators
15、 can be returned for recalibration.)If you are aware of alternativesuppliers,please provide this information to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsibletechnical committee,1which you may attend.4The sole source of supply of the
16、apparatus known to the Committee at this timeis the Magnetoscop manufactured by INSTITUT DR.POERSTER GmbH&Co.KG.in Laisen 70,72766,Reutlingen,Germany.(Probes can be returned forcalibration.)If you are aware of alternate suppliers,please provide this informationto ASTM International Headquarters.Your comments will receive careful consid-eration at a meeting of the responsible technical committee,1which you may attend.5For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact AST
