1、Designation: B 886 03 (Reapproved 2008)Standard Test Method forDetermination of Magnetic Saturation (Ms) of CementedCarbides1This standard is issued under the fixed designation B 886; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of magneticsaturation (Ms) of cemented carbide powder material
3、s andsintered products using magnetic saturation induction testinstrumentation.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with
4、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 prior to use.2. Referenced Documents2.1 ASTM Standards:2A 340 Terminology of Symbols and Definitions Relating toMagnetic Test
5、ingB 243 Terminology of Powder MetallurgyE 1316 Terminology for Nondestructive Examinations3. Terminology3.1 Definitions:3.1.1 For definition of terms used in this procedure refer toTerminology A 340, Terminology B 243, and TerminologyE 1316.3.1.2 dcdirect current.4. Summary of Test Method4.1 A test
6、 specimen is statically positioned in the magneticfield generated by dc coils or a permanent magnet and sensingcoils of the test apparatus. The specimen is magnetized toinduction saturation by the field and translated linearly that theintrinsic magnetic moment of the specimens binder phaseinduces a
7、dc current to flow in the sensing coils of the testapparatus. The induced current is proportional to the amount ofmagnetic binder phase present in the test specimen. Measure-ment of the induced current permits calculation of the intrinsicmagnetic saturation of the test sample.5. Significance and Use
8、5.1 This test method allows the nondestructive measure-ment of the magnetic fraction of the binder phase in cementedcarbide powder materials and sintered product, and may beused as an indirect measure of the carbon level in the materialor product.5.2 Measurement of magnetic saturation provides a com
9、-parison of the relative fraction of magnetic binder phase that is,cobalt, nickel, or iron, present in the material and can be usedfor acceptance of product to specification.5.3 Measurement of magnetic saturation can be used as ameasure of the quality of powder material.6. Interferences6.1 No direct
10、 absolute measurement of magnetic saturationcan be made. The measurement is a relative comparison ofstandard reference materials.6.2 Measurement of magnetic saturation is a nondestructive“bulk” measurement which is averaged over the test specimenvolume. The technique cannot be used to infer anything
11、regarding the relative distribution of the binder phase withinthe test sample.6.3 Measurement of magnetic saturation is affected by testsample size and shape, especially aspect ratio, and the compo-sition of the binder phase, that is, a mixture of ferromagneticelements of varying intrinsic magnetic
12、moments.6.4 Small test samples or test samples containing relativelylow concentrations of the binder phase may be immeasurablein that the low concentration prohibits detection by the fieldsensing coils of the specific apparatus employed.7. Apparatus7.1 Instrumentation capable of inducing magnetic sa
13、turationand then sensing the inherent intrinsic magnetic moment of themagnetic fraction of the binder phase.1This test method is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.06 on Cemented Carbides.Curren
14、t edition approved April 1, 2008. Published April 2008. Originallyapproved in 1998. Last previous edition approved in 2003 as B 88603.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume info
15、rmation, 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.7.2 Balance having a capacity of 200 g and a sensitivity of0.001 g.8. Standards8.1 No certified cemented carbide
16、 standards, powder mate-rials or sintered product, are available for magnetic saturationmeasurement. Most common practice is the development of(internal) reference materials representative of the test samplesbeing evaluated.8.2 Pure ferromagnetic materials such as cobalt (Co), iron(Fe), or Nickel (N
17、i), and iron oxide, that is, Fe3O4, with knownmagnetic moments are recommended for calibration of theinstrumentation.9. Test Specimen9.1 Test specimens may be in the form of sintered solids,unsintered powder compacts, or encapsulated powders of a sizesuitable to fit into the specimen holder of the a
18、pparatus. Thelong axis of the specimen should be perpendicular to themagnetic field of the test apparatus.10. Procedure10.1 For commercial instrumentation, refer to the equip-ment manufacturers operating manual and follow operatinginstructions.10.2 Obtain the mass of each test specimen.10.3 Position
19、 the test sample in the center of the magneticfield/sensing coils.10.4 Saturate the test specimen.10.5 Remove/translate the test specimen in the sensingcoils.10.6 Read and record the value of the intrinsic magneticsaturation from the test apparatus. Measurement units areTesla-m3per kilogram (emu per
20、 gram (csg).10.7 Relative percent of magnetic saturation of the testsample may be calculated and reported. Consideration must begiven to the composition of the binder phase with respect toferromagnetic components, and the presence of other metallicconstituents, for example, chromium (Cr) in the powd
21、ermaterial or sintered product, that would affect the binder phasecomposition or magnetic moment of the constituents.10.8 Repeat measurements can be made to obtain an aver-age value and range of values for test specimens of asymmetricshape. Orientation of the test sample should be changed withinthe
22、test apparatus sample chamber for each repeat measure-ment.11. Report11.1 Report magnetic saturation as Tesla-m3per kilogram(emu per gram), or as relative percent, (that is, magneticportion of the binder phase/total mass of binder phase in testsample).12. Precision and Bias12.1 PrecisionMeasurement
23、of magnetic saturation is arelative comparison against well characterized reference mate-rials of similar composition and mass (see 8.1). No statementabout precision can be made due to the effects of test specimensize and shape, variations in the binder phase composition thatare within material or p
24、roduct specification, and the effect ofvariations of the carbon content of the test samples (see 6.3).12.2 BiasMeasurement of magnetic saturation is a rela-tive comparison against well characterized reference materialsof similar composition and mass (see 8.1). No statement aboutbias can be made due
25、to the affects of test specimen size andshape, variations in the binder phase composition that arewithin material or product specification, and the affect ofvariations of the carbon content of the test samples (see 6.3).13. Keywords13.1 cemented carbide; magnetic saturation (Ms)ASTM International ta
26、kes 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 patent rights, and the riskof infringement of such rights, are entirely their own r
27、esponsibility.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 either for revision of this standard or for additional standardsand should be addre
28、ssed 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 hearing you shouldmake your views known to the ASTM Committee on Standards, at t
29、he 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 standard 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).B 886 03 (2008)2
