ASTM B657-18

Standard Guide for Metallographic Identification of Microstructure in Cemented Carbides

SIGNIFICANCE AND USE
4.1 The microstructure of a cemented carbide affects the material's mechanical and physical properties. This guide is not intended to be used as a specification for carbide grades. Producers and users may use the microstructural information as a guide in developing their own specifications.
SCOPE
1.1 This guide covers apparatus and procedures for the metallographic identification of microstructures in cemented carbides.  
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. Precautions applying to use of hazardous laboratory chemicals should be observed for chemicals specified in Table 1.  
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-2018
• 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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: B657 − 18
Standard Guide for
Metallographic Identification of Microstructure in Cemented
1
Carbides
This standard is issued under the fixed designation B657; 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. Terminology
1.1 This guide covers apparatus and procedures for the 3.1 Definitions of Symbols:
metallographic identification of microstructures in cemented
Symbol Definition
α phase tungsten carbide
carbides.
β phase binder (for example, Co, Ni, Fe)
1.2 This standard does not purport to address all of the
γ phase carbide of a cubic lattice (for example, TiC, TaC, NbC)
that may contain other carbides (for example, WC) in
safety concerns, if any, associated with its use. It is the
solid solution
responsibility of the user of this standard to establish appro-
η-type phases multiple carbides of tungsten and at least one metal of the
priate safety, health, and environmental practices and deter-
binder
mine the applicability of regulatory limitations prior to use.
4. Significance and Use
Precautions applying to use of hazardous laboratory chemicals
4.1 The microstructure of a cemented carbide affects the
should be observed for chemicals specified in Table 1.
material’s mechanical and physical properties. This guide is
1.3 This international standard was developed in accor-
not intended to be used as a specification for carbide grades.
dance with internationally recognized principles on standard-
Producers and users may use the microstructural information as
ization established in the Decision on Principles for the
a guide in developing their own specifications.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
5. Apparatus
Barriers to Trade (TBT) Committee.
5.1 Metallographic Microscope capable of magnifications
up to 1500 times.
2. Referenced Documents
2 5.2 Ordinary metallurgical laboratory equipment.
2.1 ASTM Standards:
5.3 Equipment for specimen preparation as outlined in
B665 Guide for Metallographic Sample Preparation of Ce-
mented Tungsten Carbides Guide B665.
3
2.2 ISO Standard:
6. Specimen Preparation
ISO 4499 Hardmetals—Metallographic Determination of
6.1 A suitable procedure is described in Guide B665.
Microstructure
7. Procedure
7.1 Examine the microstructure by gradual development of
1
This guide is under the jurisdiction of ASTM Committee B09 on Metal
the phases by etching. Examples of suitable etching techniques
Powders and Metal Powder Products and is the direct responsibility of Subcom-
are given in Table 1. Examples of the appearance of some
mittee B09.06 on Cemented Carbides.
expected phases, in fine, medium, and coarse grain sizes, are
Current edition approved April 1, 2018. Published April 2018. Originally
approved in 1979. Last previous edition approved in 2011 as B657 – 11. DOI:
given in Fig. 1.
10.1520/B0657-18.
2
7.2 Determine the presence of η-type phases by lightly
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
etching half the section with Technique 1 (see Table 1).
Standards volume information, refer to the standard’s Document Summary page on
Examine the entire section at low magnification and, if
the ASTM website.
3 necessary, at magnifications up to 1500 times. Phases of η-type
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036. are colored orange to brown in the etched portion, and white to
*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 ----------------------
B657 − 18
TABLE 1 Etching Techniques
NOTE 1—The separate solutions of potassium hexacyanoferrate (III) and potassium or sodium hydroxide may be stored for a long time, but must be
freshly mixed each day when used.
NOTE 2—The times in the conditions for etching are for concentrations listed. Deviation from these concentrations will affect times required to reveal
desired structures.
Etching
Objective
Tech- Composition of Etchants Conditions of Etching
of Etching
nique
1 Freshly prepared mixture of equal quantities of Etch at approximately 20°C for 2 to 10 s. Flush the test-piece Identification of η
10 %(mass ⁄mass) aqueous solutions of K Fe(CN) (III) section with water immediately, without removing the oxide layer. Dry phase
3 6
(potassium ferricyanide) and potassium the surface carefully with acetone
...

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: B657 − 11 B657 − 18
Standard Guide for
Metallographic Identification of Microstructure in Cemented
1
Carbides
This standard is issued under the fixed designation B657; 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 guide covers apparatus and procedures for the metallographic identification of microstructures in cemented carbides.
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. Precautions applying to use of hazardous laboratory chemicals should be
observed for chemicals specified in Table 1.
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:
B665 Guide for Metallographic Sample Preparation of Cemented Tungsten Carbides
3
2.2 ISO Standard:
ISO 4499 Hardmetals—Metallographic Determination of Microstructure
3. Terminology
3.1 Definitions of Symbols:
Symbol Definition
α phase tungsten carbide
β phase binder (for example, Co, Ni, Fe)
γ phase carbide of a cubic lattice (for example, TiC, TaC, NbC)
that may contain other carbides (for example, WC) in
solid solution
η-type phases multiple carbides of tungsten and at least one metal of the
binder
4. Significance and Use
4.1 The microstructure of a cemented carbide affects the material’s mechanical and physical properties. This guide is not
intended to be used as a specification for carbide grades. Producers and users may use the microstructural information as a guide
in developing their own specifications.
5. Apparatus
5.1 Metallographic Microscope capable of magnifications up to 1500 times.
5.2 Ordinary metallurgical laboratory equipment.
5.3 Equipment for specimen preparation as outlined in Guide B665.
1
This guide 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, 2011April 1, 2018. Published October 2011April 2018. Originally approved in 1979. Last previous edition approved in 20052011 as
B657 – 05.B657 – 11. DOI: 10.1520/B0657-11.10.1520/B0657-18.
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 American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.
*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 ----------------------
B657 − 18
TABLE 1 Etching Techniques
NOTE 1—The separate solutions of potassium hexacyanoferrate (III) and potassium or sodium hydroxide may be stored for a long time, but must be
freshly mixed each day when used.
NOTE 2—The times in the conditions for etching are for concentrations listed. Deviation from these concentrations will affect times required to reveal
desired structures.
Etching
Objective
Tech- Composition of Etchants Conditions of Etching
of Etching
nique
1 Freshly prepared mixture of equal quantities of Etch at approximately 20°C for 2 to 10 s. Flush the test-piece Identification of η
10 %(mass ⁄mass) aqueous solutions of K Fe(CN) (III) section with water immediately, without removing the oxide layer. Dry phase
3 6
(potassium ferricyanide) and potassium the surface carefully with acetone or alcohol without wiping.
or sodium hydroxide
2 A Same as 1A Etch at approximately 20°C for 2 to 4 min. Identification of α, β,
Swabbing surface may enhance the effects of etchant. and γ phases
6. Specimen Preparation
6.1 A suitable procedure is described in Guide B665.
7. Procedure
7.1 Examine the microstruc
...