ASTM B887-12
(Test Method)Standard Test Method for Determination of Coercivity (Hcs) of Cemented Carbides
Standard Test Method for Determination of Coercivity (Hcs) of Cemented Carbides
SIGNIFICANCE AND USE
Measurement of coercivity provides a relative comparison of carbide grain size, binder content, and possibly carbon deficiency for a given graded carbide material or product, and may be employed as a non-destructive measurement indicating deviation from a specified norm.
This test method allows the non-destructive estimate of average carbide grain size in sintered cemented carbide hardmetals. It is appropriate for a wide range of compositions and tungsten carbide (WC) WC grain sizes, and can be used for acceptance of material or product to specification.
SCOPE
1.1 This test method covers the determination of magnetization coercivity (Hcs) of cemented carbide materials and products using coercive force instrumentation. It is patterned after ISO 3326.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: B887 − 12
Standard Test Method for
1
Determination of Coercivity (Hcs) of Cemented Carbides
This standard is issued under the fixed designation B887; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.2 dc—direct current.
1.1 This test method covers the determination of magneti-
4. Summary of Test Method
zation coercivity (Hcs) of cemented carbide materials and
products using coercive force instrumentation. It is patterned
4.1 A test sample is positioned in the dc magnetic field of
after ISO 3326.
the test apparatus and magnetized to technical saturation. The
magnetic field polarity is then reversed and the test sample is
1.2 The values stated in SI units are to be regarded as
demagnetized by increasing the energy of the reversed mag-
standard. No other units of measurement are included in this
netic field until the test sample reaches zero magnetism. The
standard.
coercive force (Hc) is the magnetizing force required to return
1.3 This standard does not purport to address all of the
the saturated magnetic induction to zero.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Significance and Use
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. 5.1 Measurement of coercivity provides a relative compari-
son of carbide grain size, binder content, and possibly carbon
2. Referenced Documents
deficiency for a given graded carbide material or product, and
2
may be employed as a non-destructive measurement indicating
2.1 ASTM Standards:
deviation from a specified norm.
A340 Terminology of Symbols and Definitions Relating to
Magnetic Testing
5.2 This test method allows the non-destructive estimate of
B243 Terminology of Powder Metallurgy
average carbide grain size in sintered cemented carbide hard-
E177 Practice for Use of the Terms Precision and Bias in
metals. It is appropriate for a wide range of compositions and
ASTM Test Methods
tungsten carbide (WC) WC grain sizes, and can be used for
E691 Practice for Conducting an Interlaboratory Study to
acceptance of material or product to specification.
Determine the Precision of a Test Method
2.2 ISO Standard:Available from American National Stan-
6. Interferences
dards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY
6.1 Hcs measurement is a non-destructive “bulk” measure-
10036, http://www.ansi.org.
ment that is averaged over the specimen volume. Bi-modal
ISO 3326 Hardmetals - Determination of (the Magnetiza-
grain size distributions will give approximately the same Hc
tion) Coercivity
value as would be obtained from a normal grain size distribu-
tion about the same mean value.
3. Terminology
6.2 Large test specimens must be sized to fit within the
3.1 Definitions:
magnetic field coil spacing available for the apparatus em-
3.1.1 For definition of terms used in this procedure refer to
ployed.
Terminology A340 and Terminology B243.
6.3 Small test specimens may be immeasurable if their size
prohibits detection by the magnetic field coils for the apparatus
1
This test method is under the jurisdiction of ASTM Committee B09 on Metal
employed.
Powders and Metal Powder Products and is the direct responsibility of Subcom-
mittee B09.06 on Cemented Carbides.
6.4 Specimen shape, that is, symmetry and aspect ratio,
Current edition approved May 15, 2012. Published September 2012. Originally
influence Hc measurement values and repeatability of results.
approved in 1998. Last previous edition approved in 2008 as B887–03(2008)E01.
DOI: 10.1520/B0887-12.
Test specimens should be positioned with their long axis in the
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
direction of the magnetic field. Asymmetrically shaped test
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
specimens should be tested in several positions, the measure-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. ment values recorded, and the average value reported.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
B887 − 12
7. Apparatus 10.1.1.1 Repeatability limits are listed in Table 1 below.
10.1.2 Reproducibility limit (R)—Two test results shall be
7.1 Instrumentation capable of the dc magnetization of
judged not equivalent if they differ by more than the “R” value
appropriately sized test samples to technical saturation and
for tha
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: B887 − 03 (Reapproved 2008) B887 − 12
Standard Test Method for
1
Determination of Coercivity (Hcs) of Cemented Carbides
This standard is issued under the fixed designation B887; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1
ε NOTE—The units statement in subsection 1.2 was corrected editorially in April 2008.
1. Scope
1.1 This test method covers the determination of magnetization coercivity (Hcs) of cemented carbide materials and products
using coercive force instrumentation. It is patterned after ISO 3326.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
A340 Terminology of Symbols and Definitions Relating to Magnetic Testing
B243 Terminology of Powder Metallurgy
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
2.2 ISO Standard:Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036,
http://www.ansi.org.
ISO 3326 Hardmetals - Determination of (the Magnetization) Coercivity
3. Terminology
3.1 Definitions:
3.1.1 For definition of terms used in this procedure refer to Terminology A340 and Terminology B243.
3.1.2 dc—direct current.
4. Summary of Test Method
4.1 A test sample is positioned in the dc magnetic field of the test apparatus and magnetized to technical saturation. The
magnetic field polarity is then reversed and the test sample is demagnetized by increasing the energy of the reversed magnetic field
until the test sample reaches zero magnetism. The coercive force (Hc) is the magnetizing force required to return the saturated
magnetic induction to zero.
5. Significance and Use
5.1 Measurement of coercivity provides a relative comparison of carbide grain size, binder content, and possibly carbon
deficiency for a given graded carbide material or product, and may be employed as a non-destructive measurement indicating
deviation from a specified norm.
5.2 This test method allows the non-destructive estimate of average carbide grain size in sintered cemented carbide hardmetals.
It is appropriate for a wide range of compositions and tungsten carbide (WC) WC grain sizes, and can be used for acceptance of
material or product to specification.
1
This test method is under the jurisdiction of ASTM Committee B09 on Metal Powders and Metal Powder Products and is the direct responsibility of Subcommittee B09.06
on Cemented Carbides.
Current edition approved April 1, 2008May 15, 2012. Published April 2008September 2012. Originally approved in 1998. Last previous edition approved in 20032008
as B887B887–03(2008)–03.E01. DOI: 10.1520/B0887-03R08E01.10.1520/B0887-12.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
B887 − 12
6. Interferences
6.1 Hcs measurement is a non-destructive “bulk” measurement that is averaged over the specimen volume. Bi-modal grain size
distributions will give approximately the same Hc value as would be obtained from a normal grain size distribution about the same
mean value.
6.2 Large test specimens must be sized to fit within the magnetic field coil spacing available for the apparatus employed.
6.3 Small test specimens may be immeasurable if their size prohibits detection by the magnetic field coils for the apparatus
employed.
6.4 Specimen shape, that is, symmetry and aspect ratio, influence Hc measurement values and repeatability of results. Test
specimens should be positioned with their long axis in the direction of the magnetic field. Asymmetrically shaped test sp
...
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