1、Designation: A 719/A 719M 02 (Reapproved 2007)Standard Test Method forLamination Factor of Magnetic Materials1This standard is issued under the fixed designation A 719/A 719M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the yea
2、r of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers measurement of the laminationfactor (Note 1) of a specimen composed of strips cut fromma
3、gnetic material.NOTE 1Lamination factor is also termed space factor or stackingfactor.1.2 This test method shall be used in conjunction withPractice A 34/A 34M.1.3 The values and equations stated in customary (cgs-emuand inch-pound) or SI units are to be regarded separately asstandard. Within this t
4、est method, SI units are shown inbrackets. The values stated in each system may not be exactequivalents; therefore each system shall be used independentlyof the other. Combining values from the two systems mayresult in nonconformance with this test method.1.4 This standard does not purport to addres
5、s the safetyconcerns associated with its use. It is the responsibility of theuser of this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2. Referenced Documents2.1 ASTM Standards:2A 34/A 34M Practice for Sampling a
6、nd Procurement Test-ing of Magnetic Materials3. Summary of Test Method3.1 The laminated test specimen is subjected to pressure ina compression device and the resulting volume is then deter-mined from the measured specimen height, width, and length.An equivalent solid volume is calculated from the sp
7、ecimenmass and the true density of the specimen material. The ratio ofthe calculated (equivalent solid) volume to the measuredvolume is the lamination factor.4. Significance and Use4.1 Lamination factor, S, indicates the deficiency of effec-tive steel volume which is due to the presence of oxides,ro
8、ughness, insulating coatings, and other conditions affectingthe steel surface.5. Apparatus5.1 Testing MachineA compression testing machine orother compression device capable of exerting the specifiedpressure.5.2 Metal PlatesTwo flat, smooth, rigid metal plates withsquare edges and ends are required.
9、 They shall be of sufficientstiffness to distribute the pressure uniformly over the surface ofthe sample. Each plate shall be 8.46 in. 215 mm long andhave a minimum width of 1.97 in. 50 mm so that the area ofstrips under pressure when testing 1.18-in. 30-mm widespecimens will be 10 in.26450 mm2.5.2.
10、1 Extensions can be added to the plates to allow the useof micrometers or outside calipers instead of inside calipers fordetermining plate separation. Precautions must be taken toensure that, within the limits of accuracy of the measurements,no significant deflection of these extensions result from
11、the testpressure.5.3 Length-Measuring ToolsCalipers or other devices ofadequate accuracy for measurement of plate separation.6. Sampling6.1 Test strips shall be selected as representative of thesurface condition. Core loss test specimens (Epstein testspecimens) are normally used for this purpose.6.2
12、 In routine testing, where the core loss specimens are toosmall to conform to the number of strips requirement of Table1, sufficient specimens may be combined to provide anadequate test specimen. The combined specimens must be ofthe same thickness and material, have similar surfaces, and berepresent
13、ative of the surface condition of the test lot.6.3 When a referee test becomes necessary, the test speci-men must be composed of strips taken from one lot of steel. Itmust be representative of the surface condition, thickness, and1This test method is under the jurisdiction of ASTM Committee A06 onMa
14、gnetic Properties and is the direct responsibility of SubcommitteeA06.01 on TestMethods.Current edition approved Nov. 1, 2007. Published January 2008. Originallyapproved in 1975. Last previous edition approved in 2002 as A 719/A 719M-02.2For referenced ASTM standards, visit the ASTM website, www.ast
15、m.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.other var
16、iables. The shearing burrs should be removed and thestrips wiped free of loose particles.7. Test Specimen7.1 The test specimens shall consist of the number of stripsprescribed in Table 1.7.2 Each strip shall have a minimum length of 9.84 in. 250mm and a width of 1.18 in. 30 mm. See Practice A 34/A 3
17、4M.7.3 Length and width dimensions should be known to atleast 0.25 % and preferably to 0.1 %.8. Procedure8.1 Determine the mass of the test specimen by weighing.8.2 Stack the strips evenly and place them symmetricallybetween the two flat plates in the compression testing machine.8.3 Apply pressure s
18、o it is distributed uniformly across thetest specimen.8.4 The recommended standard minimum test pressure shallbe 50 psi 345 kPa. Other pressures, depending on theapplication, may be agreed upon between the seller and thepurchaser.8.5 If more than one test pressure is used, apply thepressures in asce
19、nding order.8.6 Calculate the average separation of the backing plates,or stack height, at the required pressure from measurements ofthe plates separation.8.6.1 When using a compression testing machine make fourmeasurements of the separation, one at each corner of thebacking plates.8.6.2 When using
20、a compression device designed specifi-cally for determining this factor only two measurements, takenon the longitudinal axis of the strips at each end of the plates,are required.9. Calculation9.1 Customary Units:9.1.1 Calculate the percentage lamination factor as follows:S 5 m/2.54 wld h8!# 3 100 (1
21、)where:S = lamination factor, %;m = mass of test specimen, g;w = width of test specimen, cm;l = length of test specimen, cm;d = density of the specimen material;g/cm3, (see Practice A 34/A 34M); andh8 = measured average separation of the plate facesor stack height, in.9.2 SI Units:9.2.1 Calculate th
22、e percentage lamination factor as follows:S 5 m/wldh8!# 3 100 (2)where:S = lamination factor, %;m = mass of test specimen, g;w = width of specimen, mm;l = length of specimen, mm;d = density of specimen material, kg/m3; andh8 = measured stack height, mm.10. Precision and Bias10.1 PrecisionThe precisi
23、on of the procedure in this testmethod for measuring the lamination factor of magneticmaterials is being determined.10.2 BiasSince there is no accepted reference material fordetermining the bias for the procedure in this test method formeasuring lamination factor, bias has not been determined.11. Ke
24、ywords11.1 lamination factor; space factor; stacking factorASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such pat
25、ent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited eit
26、her for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair
27、hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this stand
28、ard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 1 Number of Strips in Lamination Factor Test SpecimensElectrical SheetGage NumberAThicknessNumber ofStrips perTest S
29、pecimenin. mm16 0.0625 1.59 2417 0.0560 1.42 2418 0.0500 1.27 3019 0.0453 1.15 3020 0.0375 0.95 4021 0.0340 0.86 4022 0.0310 0.79 5023 0.0280 0.71 5024 0.0250 0.64 6025 0.0220 0.55 6026 0.0185 0.47 8027 0.0170 0.43 8028 0.0155 0.39 8029 0.0140 0.35 10030 0.0125 0.32 10031 0.0100 0.25 100ANoteFor the sake of convenience for the users of this test method, theelectrical sheet gage numbers are listed for the nominal thickness values listedabove.A 719/A 719M 02 (2007)2
