ASTM B276-05(2015)

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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Sep-2015
• ICS: 77.160 - Powder metallurgy
• Technical Committee: B09 - Metal Powders and Metal Powder Products
• Drafting Committee: B09.06 - Cemented Carbides

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: B276 − 05 (Reapproved 2015)
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.Anumber 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 acceptablelevelofporosity,thistestmethodillustratesabroad
range of porosity levels for each of three porosity types. This
1.1 This test method specifies procedures for the metallo-
testmethodisnotintendedtobeusedasaspecification,butthe
graphic determination of apparent porosity in cemented car-
levels shown here may be cited in specifications written by
bides.
producers and users of cemented carbides.
NOTE 1—The term “apparent porosity” is construed to mean all
microstructures observed on a properly prepared, unetched surface,
5. Interferences
including structures resulting from uncombined carbon, non-metallic
5.1 Lack of adequate pressure on the specimen during
inclusions, etc., as well as true, inherent porosity.
polishing may result in material being torn from the surface of
1.2 This standard does not purport to address all of the
thespecimen.Thisconditionmaybeerroneouslyinterpretedas
safety concerns, if any, associated with its use. It is the
porosity.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
6. Apparatus
bility of regulatory limitations prior to use.
6.1 A metallographic microscope permitting observation
and measurement up to a magnification of 200×.
2. Referenced Documents
2
6.2 Equipment for the metallographic preparation of test
2.1 ASTM Standards:
specimens.
B243Terminology of Powder Metallurgy
B665Guide for Metallographic Sample Preparation of Ce-
7. Specimen Preparation
mented Tungsten Carbides
3
7.1 Where possible, specimens should be metallographi-
2.2 ASTM Adjunct:
callymountedinaplasticmaterial,sothattheycanbepolished
ADJB0276AApparent Porosity (4 prints of 4 photomicro-
withoutroundingtheedges.Largerspecimensmaybepolished
graphs each)
without mounting. When the specimens are too large, they
3. Terminology shall be sectioned using a diamond cut-off wheel or by
fracturing (appropriate safety precautions shall be utilized
3.1 Definitions—Definition of powder metallurgy terms can
when fracturing a specimen). The area selected for examina-
be found in Terminology B243.
tion should represent, as nearly as possible, the entire cross
section.
4. Significance and Use
7.2 The specimen shall be prepared for metallographic
4.1 Cemented carbide materials may contain small voids
examination. A suitable procedure is described in Practice
that, depending on the application, may affect the performance
B665.Thesurfacetobeexaminedshallbeunetchedandfreeof
of the product. To assist users in specifying the maximum
grinding and polishing marks.
1
8. Procedure
This test method is under the jurisdiction of ASTM Committee B09 on Metal
Powders and Metal Powder Products and is the direct responsibility of Subcom-
8.1 Poresizeshallbedefinedasthemaximumdimensionof
mittee B09.06 on Cemented Carbides.
the pore. Make special reference to the presence of cracks and
Current edition approved Oct. 1, 2015. Published October 2015. Originally
approvedin1954.Lastpreviouseditionapprovedin2010asB276–91(2010).DOI:
slits, as well as nonmetallic inclusions.
10.1520/B0276-05R15.
2
8.2 Classification of Type “A” and “C” apparent porosity is
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
basedentirelyoncomparisonofthemicrostructuresfoundwith
Standards volume information, refer to the standard’s Document Summary page on 3
the illustrations in Figs. 1, 3 and 4 of ADJB0276A with due
the ASTM website.
3
consideration to the difference in field of view of the micro-
Available from ASTM International Headquarters. Order Adjunct No.
ADJB0276A. scope compared to the area of the illustrations. This can be
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
B276 − 05 (2015)
accomplished by scanning the specimen surface under the of area between the illustrations in Fig. 2 of ADJB0276A and
microscope at the appropriate magnification, and noting which that observed in the microscope (see A1.4), classify the “B”
of the illustrations most nearly represents the fields observed. porosityasB04,B06,orB08withreferencetotheillustrations
Chooseanareafullyrepr
...

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 2010) B276 − 05 (Reapproved 2015)
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 and health practices and determine the applicability of regulatory
limitations prior to use.
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:
ADJB0276A Apparent Porosity (4 prints of 4 photomicrographs each)
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
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
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 Sept. 1, 2010Oct. 1, 2015. Published October 2010 October 2015. Originally approved in 1954. Last previous edition approved in 20052010 as
B276 – 91(2005)e1.(2010). DOI: 10.1520/B0276-05R10.10.1520/B0276-05R15.
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. ADJB0276A.
*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 − 05 (2015)
sectioned using a diamond cut-off wheel or by fracturing (appropriate safety precautions shall be utilized when fracturing a
specimen). The area selected for examination should represent, as nearly as possible, the entire cross section.
7.2 The specimen shall be prepared for metallographic examination. A suitable procedure is described in Practice B665.The
surface to be examined shall be unetched and free of grinding and polishing marks.
8. Procedure
8.1 Pore size shall be defined as the maximum dimension of the pore. Make special reference to the presence of cracks and slits,
as well as nonmetallic inclusions.
8.2 Classification of Type “A” and “C” apparent porosity is based entirely on comparison of the microstructures found with the
3
illustrations in Figs. 1, 3 and 4 of ADJB027
...