ASTM B276-21

Standard Test Method for Apparent Porosity in Cemented Carbides

SIGNIFICANCE AND USE
4.1 Cemented carbide materials may contain small voids that, depending on the application, may affect the performance of the product. To assist users in specifying the maximum acceptable level of porosity, this test method illustrates a broad range of porosity levels for each of three porosity types. This test method is not intended to be used as a specification, but the levels shown here may be cited in specifications written by producers and users of cemented carbides.
SCOPE
1.1 This test method specifies procedures for the metallographic determination of apparent porosity in cemented carbides.  
Note 1: The term “apparent porosity” is construed to mean all microstructures observed on a properly prepared, unetched surface, including structures resulting from uncombined carbon, non-metallic inclusions, etc., as well as true, inherent porosity.  
1.2 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Aug-2021
• ICS: 77.160 - Powder metallurgy
• Technical Committee: B09 - Metal Powders and Metal Powder Products
• Drafting Committee: B09.06 - Cemented Carbides

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: B276 − 21
Standard Test Method for
1
Apparent Porosity in Cemented Carbides
This standard is issued under the fixed designation B276; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* 3. Terminology
1.1 This test method specifies procedures for the metallo- 3.1 Definitions—Definition of powder metallurgy terms can
graphic determination of apparent porosity in cemented car-
be found in Terminology B243.
bides.
4. Significance and Use
NOTE 1—The term “apparent porosity” is construed to mean all
microstructures observed on a properly prepared, unetched surface,
4.1 Cemented carbide materials may contain small voids
including structures resulting from uncombined carbon, non-metallic
that, depending on the application, may affect the performance
inclusions, etc., as well as true, inherent porosity.
of the product. To assist users in specifying the maximum
1.2 This standard does not purport to address all of the
acceptable level of porosity, this test method illustrates a broad
safety concerns, if any, associated with its use. It is the
range of porosity levels for each of three porosity types. This
responsibility of the user of this standard to establish appro-
test method is not intended to be used as a specification, but the
priate safety, health, and environmental practices and deter-
levels shown here may be cited in specifications written by
mine the applicability of regulatory limitations prior to use.
producers and users of cemented carbides.
1.3 This international standard was developed in accor-
dance with internationally recognized principles on standard-
5. Interferences
ization established in the Decision on Principles for the
5.1 Lack of adequate pressure on the specimen during
Development of International Standards, Guides and Recom-
polishing may result in material being torn from the surface of
mendations issued by the World Trade Organization Technical
the specimen. This condition may be erroneously interpreted as
Barriers to Trade (TBT) Committee.
porosity.
2. Referenced Documents
6. Apparatus
2
2.1 ASTM Standards:
6.1 A metallographic microscope permitting observation
B243 Terminology of Powder Metallurgy
and measurement up to a magnification of 200×.
B665 Guide for Metallographic Sample Preparation of Ce-
mented Tungsten Carbides
6.2 Equipment for the metallographic preparation of test
3
specimens.
2.2 ISO Standard:
ISO 4499-4:2016 Hardmetals — Metallographic Determina-
tion of Microstructure — Part 4: Characterisation of 7. Specimen Preparation
Porosity, Carbon Defects and Eta-phase Content
7.1 Where possible, specimens should be metallographi-
cally mounted in a plastic material, so that they can be polished
without rounding the edges. Larger specimens may be polished
1
This test method is under the jurisdiction of ASTM Committee B09 on Metal without mounting. When the specimens are too large, they
Powders and Metal Powder Products and is the direct responsibility of Subcom-
shall be sectioned using a diamond cut-off wheel or by
mittee B09.06 on Cemented Carbides.
fracturing (appropriate safety precautions shall be utilized
Current edition approved Sept. 1, 2021. Published February 2022. Originally
when fracturing a specimen). The area selected for examina-
approved in 1954. Last previous edition approved in 2015 as B276 – 05(2015). DOI:
10.1520/B0276-21.
tion should represent, as nearly as possible, the entire cross
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
section.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
7.2 The specimen shall be prepared for metallographic
the ASTM website.
examination. A suitable procedure is described in Guide B665.
3
Available from International Organization for Standardization (ISO), ISO
The surface to be examined shall be unetched and free of
Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, https://www.iso.org. grinding and polishing marks.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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B276 − 21
8. Procedure count by the area exam
...

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.
Designation: B276 − 05 (Reapproved 2015) B276 − 21
Standard Test Method for
1
Apparent Porosity in Cemented Carbides
This standard is issued under the fixed designation B276; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope Scope*
1.1 This test method specifies procedures for the metallographic determination of apparent porosity in cemented carbides.
NOTE 1—The term “apparent porosity” is construed to mean all microstructures observed on a properly prepared, unetched surface, including structures
resulting from uncombined carbon, non-metallic inclusions, etc., as well as true, inherent porosity.
1.2 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
B243 Terminology of Powder Metallurgy
B665 Guide for Metallographic Sample Preparation of Cemented Tungsten Carbides
3
2.2 ASTM Adjunct:ISO Standard:
ADJB0276AISO 4499-4:2016 Apparent Porosity (4 prints of 4 photomicrographs each)Hardmetals — Metallographic
Determination of Microstructure — Part 4: Characterisation of Porosity, Carbon Defects and Eta-phase Content
3. Terminology
3.1 Definitions—Definition of powder metallurgy terms can be found in Terminology B243.
4. Significance and Use
4.1 Cemented carbide materials may contain small voids that, depending on the application, may affect the performance of the
product. To assist users in specifying the maximum acceptable level of porosity, this test method illustrates a broad range of
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 Oct. 1, 2015Sept. 1, 2021. Published October 2015February 2022. Originally approved in 1954. Last previous edition approved in 20102015
as B276 – 91B276 – 05(2010).(2015). DOI: 10.1520/B0276-05R15.10.1520/B0276-21.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from ASTM International Headquarters. Order Adjunct No.International Organization for Standardization (ISO), ADJB0276A. ISO Central Secretariat, Chemin
de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland, https://www.iso.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
B276 − 21
porosity levels for each of three porosity types. This test method is not intended to be used as a specification, but the levels shown
here may be cited in specifications written by producers and users of cemented carbides.
5. Interferences
5.1 Lack of adequate pressure on the specimen during polishing may result in material being torn from the surface of the specimen.
This condition may be erroneously interpreted as porosity.
6. Apparatus
6.1 A metallographic microscope permitting observation and measurement up to a magnification of 200×.
6.2 Equipment for the metallographic preparation of test specimens.
7. Specimen Preparation
7.1 Where possible, specimens should be metallographically mounted in a plastic material, so that they can be polished without
rounding the edges. Larger specimens may be polished without mounting. When the specimens are too large, they shall be
sectioned using a diamond cut-off wheel or by fracturing (appropriate safety precautions shall be utilized when fracturing a
spe
...