ASTM B930-03(2017)

Standard Test Method for Rating Grain Size and Frequency of Abnormally Large Grains in Cemented Tungsten Carbides (Hardmetals)

SIGNIFICANCE AND USE
5.1 The microstructure and grain growth of cemented tungsten carbides affect the material's mechanical and physical properties. The grain size and distribution will affect the material's wear resistance and fracture toughness. Abnormally large grains as compared to the background may introduce an area of weakness in a sintered part.  
5.2 This test method may be used in acceptance testing of cemented tungsten carbide materials or the tungsten carbide powder used in their manufacture. The specified grain size used for the E-Rating is to be agreed upon between purchaser and supplier.
SCOPE
1.1 This test method describes a procedure for measuring abnormally large grains and the frequency of those grains in cemented tungsten carbides (hardmetals).  
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.  
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: Historical
• Publication Date: 31-Mar-2017
• 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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: B930 − 03 (Reapproved 2017)
Standard Test Method for
Rating Grain Size and Frequency of Abnormally Large
1
Grains in Cemented Tungsten Carbides (Hardmetals)
This standard is issued under the fixed designation B930; 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 3.2.2 L-Rating—the size, in µm, of the largest grain ob-
served in a fully-etched specimen.
1.1 This test method describes a procedure for measuring
abnormally large grains and the frequency of those grains in
4. Summary of Test Method
cemented tungsten carbides (hardmetals).
4.1 Apolished and fully etched specimen/specimens having
1.2 This standard does not purport to address all of the
2
a minimum observable area of 0.5 cm is examined using a
safety concerns, if any, associated with its use. It is the
metallograph. Abnormally large grains, compared to the finer-
responsibility of the user of this standard to establish appro-
grained background material, are identified. These grains are
priate safety and health practices and determine the applica-
categorized as: ( 1) The number of grains larger than a
bility of regulatory limitations prior to use.
specified size, or ( 2) The largest grain observed, or both.
1.3 This international standard was developed in accor-
dance with internationally recognized principles on standard-
5. Significance and Use
ization established in the Decision on Principles for the
5.1 The microstructure and grain growth of cemented tung-
Development of International Standards, Guides and Recom-
sten carbides affect the material’s mechanical and physical
mendations issued by the World Trade Organization Technical
properties. The grain size and distribution will affect the
Barriers to Trade (TBT) Committee.
material’s wear resistance and fracture toughness.Abnormally
large grains as compared to the background may introduce an
2. Referenced Documents
area of weakness in a sintered part.
2
2.1 ASTM Standards:
5.2 This test method may be used in acceptance testing of
B243 Terminology of Powder Metallurgy
cemented tungsten carbide materials or the tungsten carbide
B406 Test Method for Transverse Rupture Strength of Ce-
powderusedintheirmanufacture.Thespecifiedgrainsizeused
mented Carbides
for the E-Rating is to be agreed upon between purchaser and
B657 GuideforMetallographicIdentificationofMicrostruc-
supplier.
ture in Cemented Carbides
B665 Guide for Metallographic Sample Preparation of Ce-
6. Apparatus
mented Tungsten Carbides
6.1 Metallographic Microscope, capable of magnifications
3. Terminology
of up to 1500×.
3.1 Definitions—Definitions of powder metallurgy terms
6.2 Ordinary metallurgical laboratory equipment.
can be found in Terminology B243.
6.3 Equipment for specimen preparation as outlined in
3.2 Definitions of Terms Specific to This Standard:
Guide B665.
2
3.2.1 E-Rating—the number/cm of grains larger than a
specified size in a fully-etched specimen. 7. Test Specimens
7.1 Specimen Size—The recommended specimen shall be
the standard transverse rupture specimen as specified in Test
1
This test method is under the jurisdiction of ASTM Committee B09 on Metal
Method B406; that is, ground to the following dimensions:
Powders and Metal Powder Products and is the direct responsibility of Subcom-
mittee B09.06 on Cemented Carbides.
5.00 6 0.25 mm (0.200 6 0.010 in) thick by 6.25 6 0.25 mm
Current edition approved April 1, 2017. Published April 2017. Originally
(0.250 6 0.010 in) wide by 19.0 mm (0.750 6 in) long.
approvedin2003.Lastpreviouseditionapprovedin2012asB930 – 03(2012).DOI:
Alternatively, the specimen shall be a size to provide a
10.1520/B0930-03R17.
2
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or minimum 0.5 cm surface area of examination, or it may
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
consist of several samples that provide this minimum area.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 7.2 Specimen Preparation:
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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B930 − 03 (2017)
7.2.1 Polish the specimen/specimens according to the pro- 9. Report
cedure described in Guide B665, or other suitable metallo-
9.1 The report shall include the following:
graphic polishing procedure. If using the recommended
9.1.1 Reference to this test method,
specimen, polish the 6.25 by 19.0 mm side.
9.1.2 Complete identification of the test specimen,
9.1.3 Details of any occurrence t
...

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: B930 − 03 (Reapproved 2012) B930 − 03 (Reapproved 2017)
Standard Test Method for
Rating Grain Size and Frequency of Abnormally Large
1
Grains in Cemented Tungsten Carbides (Hardmetals)
This standard is issued under the fixed designation B930; 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
1.1 This test method describes a procedure for measuring abnormally large grains and the frequency of those grains in cemented
tungsten carbides (hardmetals).
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.
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
B406 Test Method for Transverse Rupture Strength of Cemented Carbides
B657 Guide for Metallographic Identification of Microstructure in Cemented Carbides
B665 Guide for Metallographic Sample Preparation of Cemented Tungsten Carbides
3. Terminology
3.1 Definitions—Definitions of powder metallurgy terms can be found in Terminology B243.
3.2 Definitions of Terms Specific to This Standard:
2
3.2.1 E-Rating—the number/cm of grains larger than a specified size in a fully-etched specimen.
3.2.2 L-Rating—the size, in μm, of the largest grain observed in a fully-etched specimen.
4. Summary of Test Method
2
4.1 A polished and fully etched specimen/specimens having a minimum observable area of 0.5 cm is examined using a
metallograph. Abnormally large grains, compared to the finer-grained background material, are identified. These grains are
categorized as: ( 1) The number of grains larger than a specified size, or ( 2) The largest grain observed, or both.
5. Significance and Use
5.1 The microstructure and grain growth of cemented tungsten carbides affect the material’s mechanical and physical properties.
The grain size and distribution will affect the material’s wear resistance and fracture toughness. Abnormally large grains as
compared to the background may introduce an area of weakness in a sintered part.
5.2 This test method may be used in acceptance testing of cemented tungsten carbide materials or the tungsten carbide powder
used in their manufacture. The specified grain size used for the E-Rating is to be agreed upon between purchaser and supplier.
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, 2012April 1, 2017. Published October 2012April 2017. Originally approved in 2003. Last previous edition approved in 20082012 as
B930 – 03(2008).(2012). DOI: 10.1520/B0930-03R12.10.1520/B0930-03R17.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
B930 − 03 (2017)
6. Apparatus
6.1 Metallographic Microscope, capable of magnifications of up to 1500×.
6.2 Ordinary metallurgical laboratory equipment.
6.3 Equipment for specimen preparation as outlined in Guide B665.
7. Test Specimens
7.1 Specimen Size—The recommended specimen shall be the standard transverse rupture specimen as specified in Test Method
B406; that is, ground to the following dimensions: 5.00 6 0.25 mm (0.200 6 0.010 in) thick by 6.25 6 0.25 mm (0.250 6 0.010
2
in) wide by 19.0 mm (0.750 6 in) long. Alternatively, the specimen shall be a size to provide a minimum 0.5 cm surface area
of examination, or it may consist of several samples that provide this minimum area.
7.2 Specimen Preparation:
7.2.1 Polish the specim
...