ASTM_B_886_-_12.pdf

Designation:B88612Standard Test Method forDetermination of Magnetic Saturation(Ms)of CementedCarbides1This standard is issued under the fixed designation B886;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()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 materials 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 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:2A340 Terminology of Symbols and Definitions Relating toMagnetic TestingB243 Terminology of Powder MetallurgyE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1316 Terminology for Nondestructive Examinations3.Terminology3.1 Definitions:3.1.1 For definition of terms used in this procedure refer toTerminology A340,Terminology B243,and TerminologyE1316.3.1.2 dcdirect current.4.Summary of Test Method4.1 A test 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 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 Use5.1 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-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 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 anythingregarding 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 moments.6.4 Small test samples or test samples containing relativelylow concentrations of the binder phase may be immeasurable1This 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.Current edition approved May 15,2012.Published September 2012.Originallyapproved in 1998.Last previous edition approved in 2008 as B88603(2008).DOI:10.1520/B0886-12.2For referenced ASTM standards,visit the ASTM website,www.astm.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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 in that the low concentration prohibits detection by the fieldsensing coils of the specific apparatus employed.7.Apparatus7.1 Instrumentation capable of inducing magnetic saturationand then sensing the inherent intrinsic magnetic moment of themagnetic fraction of the binder phase.7.2 Balance having a capacity of 200 g and a sensitivity of0.001 g.8.Standards8.1 No certified cemented carbide 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(Ni),and iron oxide,that is,Fe3O4,with knownmagnetic moments are recommended for calibration o