1、Designation: B886 12Standard 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 re
2、vision. 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 product
3、s 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 theres
4、ponsibility 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
5、 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
6、 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 ma
7、gnetized 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 sp
8、ecimen. 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 prod
9、uct, 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 t
10、o 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 s
11、aturation 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,
12、 especially aspect ratio, and the compo-sition of the binder phase, that is, a mixture of ferromagneticelements of varying intrinsic magnetic moments.1This test method is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom
13、-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
14、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.6.4 Small test samples or test samples c
15、ontaining 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 saturationand then sensing the inherent intrinsic
16、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
17、 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 of theinstrumentation.9. Test Spe
18、cimen9.1 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 apparatus. Thelong axis of the specimen should be perpendicular to themagnetic field of the test apparatus.10. Procedure10.1 For
19、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 the test sample in the center of the magneticfield/sensing coils.10.4 Saturate the test specimen.10.5 Remove/translate the test
20、 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 gram (csg).10.7 Relative percent of magnetic saturation of the testsample may be calculated and reported. Consideration must be
21、given to the composition of the binder phase with respect toferromagnetic components, and the presence of other metallicconstituents, for example, chromium (Cr) in the powdermaterial or sintered product, that would affect the binder phasecomposition or magnetic moment of the constituents.10.8 Repeat
22、 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 test apparatus sample chamber for each repeat measure-ment.11. Report11.1 Report magnetic saturation as Tesla-m3per kilogram(emu
23、 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 PrecisionThe precision of this test method is basedon an interlaboratory study of ASTM B886- Standard TestMethod for Determination of Magnetic Satura
24、tion (Ms) ofCemented Carbides, conducted in 2010. Three laboratoriesparticipated in this study, recording the magnetic saturation onthree specimens each, of ten different materials. This procedurewas performed three times on each material in order todetermine the precision of the test method. Every
25、“test result”represents an individual observation. Except for the limitednumber of participating laboratories, Practice E691 was fol-lowed for the design and analysis of the data.312.1.1 Repeatability limit (r)Two test results obtainedwithin one laboratory shall be judged not equivalent if theydiffe
26、r by more than the “r” value for that material; “r” is theinterval representing the critical difference between two testresults for the same material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory.12.1.1.1 Repeatability limits are listed in Table 1 below
27、.12.1.2 Reproducibility limit (R)Two test results shall bejudged not equivalent if they differ by more than the “R” valuefor that material; “R” is the interval representing the criticaldifference between two test results for the same material,obtained by different operators using different equipment
28、 indifferent laboratories.12.1.2.1 Reproducibility limits are listed in Table 1 below.12.1.3 The above terms (repeatability limit and reproduc-ibility limit) are used as specified in Practice E177.12.1.4 Any judgment in accordance with statement 9.1.1and 9.1.2 would normally have an approximate 95%
29、probabil-ity of being correct, however the precision statistics obtained inthis ILS must not be treated as exact mathematical quantitieswhich are applicable to all circumstances and uses. The limitednumber of laboratories reporting results guarantees that therewill be times when differences greater
30、than predicted by theILS results will arise, sometimes with considerably greater or3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:B09-1017.TABLE 1 Magnetic Saturation (T-m3/kg)MATERIAL AverageAsr sR r R1 0.00130 0.00 0.00 0.00
31、0.009 0.08690 0.00 0.00 0.00 0.004 0.10290 0.00 0.00 0.00 0.003 0.14478 0.00043 0.00075 0.00121 0.002105 0.16140 0.00 0.00 0.00 0.006 0.19340 0.00 0.00 0.00 0.007 0.22274 0.00043 0.00043 0.00121 0.0012110 0.31539 0.00053 0.00053 0.00149 0.001498 0.43313 0.00066 0.00071 0.00185 0.002002 0.44962 0.000
32、88 0.00133 0.00247 0.00373AThe average of laboratories calculated averagesB886 122smaller frequency than the 95% probability limit would imply.Consider the precision limits as general guides, and theassociated probability of 95% as only a rough indicator of whatcan be expected.12.2 BiasMeasurement o
33、f 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 to the affects of test specimen size andshape, variations in the binder phase composition that arewithin material or product
34、 specification, and the affect ofvariations of the carbon content of the test samples (see 6.3).12.3 The precision statement was determined through sta-tistical examination of 90 results, from three laboratories, onthe materials described in the table below.Material Description1 6.7%Ni, 0.15%VC, bal
35、ance WC2 25%Co, 1.5%TaC, 1.5%NbC, balance WC3 8%Co, 0.32%VC, balance WC4 6.25%Co, 1.5%TaC, 1.5%NbC, balance WC5 8.5%Co,8%TiC, 6.8%TaC, 3%NbC, balance WC6 10%Co, 0.25%VC, balance WC7 12.25%Co, balance WC8 25%Co, 0.3%VC, balance WC9 4.5%Co, 1%Ni, 0.5%VC, 0.4%Cr3C2, balance WC10 16%Co, balance WC13. Ke
36、ywords13.1 cemented carbide; magnetic saturation (Ms)ASTM 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 patent ri
37、ghts, 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 either fo
38、r 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 hearin
39、g 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 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).B886 123
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