ASTM G209-14(2018)
(Practice)Standard Practice for Detecting mu-phase in Wrought Nickel-Rich, Chromium, Molybdenum-Bearing Alloys
Standard Practice for Detecting mu-phase in Wrought Nickel-Rich, Chromium, Molybdenum-Bearing Alloys
SIGNIFICANCE AND USE
4.1 These test methods describe laboratory tests to determine the presence of mu-phase in Wrought Nickel-Rich, Chromium, and Molybdenum-Bearing Alloys through comparison of microstructure observed for etched metallographic specimens to a glossary of photomicrographs displaying the presence and absence of mu-phase in the microstructure. The presence of mu-phase in the microstructure may significantly reduce the corrosion resistance, strength, toughness and ductility of Wrought Nickel-Rich, Chromium, and Molybdenum-Bearing Alloys.
SCOPE
1.1 This practice incorporates etching and metallographic examination of Wrought Nickel-Rich, Chromium, Molybdenum-Bearing Alloys such as, but not limited to, UNS N06686 and UNS N10276.
1.2 Microstructures have a strong influence on properties and successful application of metals and alloys. The presence of mu-phase in the microstructure may significantly reduce the corrosion resistance of Wrought Nickel-Rich, Chromium, and Molybdenum-Bearing Alloys.
1.3 This practice may be used to determine the presence of mu-phase in Wrought Nickel-Rich, Chromium, and Molybdenum-Bearing Alloys through comparison of microstructure observed for etched metallographic specimens to a glossary of photomicrographs displaying the presence and absence of mu-phase in the microstructure.
1.4 The values stated in SI units are to be regarded as the standard. Other units are given in parentheses for information only.
1.5 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.
1.6 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.
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Designation: G209 − 14 (Reapproved 2018)
Standard Practice for
Detecting mu-phase in Wrought Nickel-Rich, Chromium,
Molybdenum-Bearing Alloys
This standard is issued under the fixed designation G209; 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.
1. Scope 2. Referenced Documents
1.1 This practice incorporates etching and metallographic 2.1 ASTM Standards:
examination of Wrought Nickel-Rich, Chromium, D1193Specification for Reagent Water
Molybdenum-BearingAlloys such as, but not limited to, UNS E3Guide for Preparation of Metallographic Specimens
N06686 and UNS N10276. E7Terminology Relating to Metallography
E1245Practice for Determining the Inclusion or Second-
1.2 Microstructures have a strong influence on properties
Phase Constituent Content of Metals byAutomatic Image
and successful application of metals and alloys. The presence
Analysis
ofmu-phaseinthemicrostructuremaysignificantlyreducethe
E1268Practice for Assessing the Degree of Banding or
corrosion resistance of Wrought Nickel-Rich, Chromium, and
Orientation of Microstructures
Molybdenum-Bearing Alloys.
G193Terminology and Acronyms Relating to Corrosion
1.3 This practice may be used to determine the presence of
mu-phase in Wrought Nickel-Rich, Chromium, and 3. Terminology
Molybdenum-Bearing Alloys through comparison of micro-
3.1 Definitions:
structure observed for etched metallographic specimens to a
3.1.1 The terminology used herein, if not specifically de-
glossary of photomicrographs displaying the presence and
fined otherwise, shall be in accordance with Terminology
absence of mu-phase in the microstructure.
G193. Definitions provided herein and not given in Terminol-
ogy G193 are limited only to this practice.
1.4 The values stated in SI units are to be regarded as the
standard. Other units are given in parentheses for information 3.1.2 For metallographic definitions used in this practice,
only. refer to Terminology E7.
3.1.3 For evaluation of inclusions, secondary phases and
1.5 This standard does not purport to address all of the
banding, if desired, refer to Practices E1245 and E1268.
safety concerns, if any, associated with its use. It is the
3.2 Definitions of Terms Specific to This Standard:
responsibility of the user of this standard to establish appro-
3.2.1 mu-phase (µ), n—rhombohedral phase which may
priate safety, health, and environmental practices and deter-
occur in Nickel-Rich, Chromium, Molybdenum-Bearing Al-
mine the applicability of regulatory limitations prior to use.
loysandmayoccurascoarse,irregularplatelets,whichformat
1.6 This international standard was developed in accor-
high temperature.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4. Significance and Use
Development of International Standards, Guides and Recom-
4.1 These test methods describe laboratory tests to deter-
mendations issued by the World Trade Organization Technical
mine the presence of mu-phase in Wrought Nickel-Rich,
Barriers to Trade (TBT) Committee.
Chromium, and Molybdenum-Bearing Alloys through com-
parison of microstructure observed for etched metallographic
This practice is under the jurisdiction ofASTM Committee G01 on Corrosion
of Metals and is the direct responsibility of Subcommittee G01.05 on Laboratory
Corrosion Tests. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2018. Published November 2018. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2012. Last previous edition approved in 2014 as G209–14. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/G0209-14R18. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G209 − 14 (2018)
specimens to a glossary of photomicrographs displaying the 5.2 Coarse Grinding—Use a 120 grit silicon carbide (SiC)
presence and absence of mu-phase in the microstructure. The wet-belt or disk grinder and light contact pressure to obtain a
presence of mu-phase in the microstructure may significantly plane surface free from deep grooves. In addition to producing
reduce the corrosion resistance, strength, toughness and duc- a flat surface, this procedure removes burred edges or other
tility of Wrought Nickel-Rich, Chromium, and Molybdenum- mechanical damage which may have occurred during section-
Bearing Alloys. ing.
5.3 Mounting—Toensureflatness,andfacilitatehandling,it
5. Sample Preparation and Etching
is recommended that specimens be mounted in phenolic,
5.1 Sectioning:
acrylic or cold-setting epoxy resins. Epoxy resins involve the
5.1.1 The selection of test specimens for metallographic
blending of a liquid or powder resin in a suitable hardener to
examination is extremely important because, if their interpre-
initiate an exothermic reaction to promote hardening and
tationistobeofvalue,thespecimensmustberepresentativeof
curing at room temperature.This usually requires an overnight
the material that is being studied and shall be per location E
operation.However,anadvantageofepoxyisthatthemountis
(longitudinal section perpendicular to rolled surface) for plate
semitransparent and permits observation of all sides of the
and sheet and per location G (radial longitudinal section) for
specimen during each phase of the preparation. (The advan-
rod and bar per Fig. 1 (Guide E3).The intent or purpose of the
tages and use of acrylic mounting resin are similar to epoxy.)
metallographic examination will usually dictate the location of
Compression molding techniques may be used with phenolic
the specimens to be studied. For rod and bar test specimens
powders to produce the standard 31.7-mm (1¼-in.) diameter
specifically, samples are taken from location G as seen in Fig.
mounts.Phenolicmountsareconvenientwhentimeconstraints
1. Triplicate test specimens shall be evaluated for determina-
do not permit an overnight cold-setting operation.
tion of the presence of mu-phase.
5.4 Fine Grinding and Polishing—Rotating discs flushed
5.1.2 Cut the specimen to a convenient size using any of
with running water are recommended with successively finer
various types of silicon carbide, diamond, boron carbide or
grit papers of 220, 320, 400, and 600 grit SiC. (A light to
other carbide cutoff blades. Deformation damage can be
medium amount of pressure is exerted on the specimen to
minimized by using thin cutoff wheels 0.78 mm ( ⁄32 in.) thick
minimize the depth of deformation). Best results are obtained
asopposedto1.58mm( ⁄16in.).Nevercutdry.Useofadequate
on the 600 SiC paper by grinding the specimen twice.
water coolant is desired to reduce the amount of disturbed
Specimens shall be rotated 90 degrees after each step until the
metal created, in part, from frictional heat during this phase of
abrasive scratches from the preceding grit have been removed.
preparation. The original microstructure of a specimen may
In each step, the grinding time shall be increased to twice as
also be radically altered, (at least superficially, on the cut
long as that required to remove previous scratches. This
surface)duetometallurgicalchangesifanexcessiveamountof
ensures removal of disturbed metal from the previous step.
frictional heat is generated.
Considerable care shall be used in the fine grinding stage to
prevent the formation of artifacts. See Guide E3 for automated
method.
3 5.5 Rough Polishing—The specimen shall be washed and,
Manning, Paul E., Ph.D., Metallographic Preparation of 686 Etching
preferably, ultrasonically cleaned to ensure the complete re-
Specimens, Haynes International, Inc., Kokomo, IN, 2011.
movalofsiliconcarbidecarryoverfromthefinegrindingstage.
Anaplesstypeclothshallbechargedwith9-µmdiamondpaste,
andwatermaybeusedasthelubricant.Thespecimenismoved
countertothedirectionoftherotatingpolishingwheelfromthe
center to the outer periphery around the entire lapping surface.
Heavy pressure is used with diamond abrasive techniques to
gainthemaximumcuttingrate.Attheconclusionofthisstage,
the specimen shall again be cleaned to remove any diamond
polishing residue remaining in pinholes, cracks, and cavities.
5.6 Polishing:
5.6.1 Semi-final and final polishing operations on a major
portion of metallographic specimens may be completed on
vibratorypolishingunits.Anylonpolishingclothusingaslurry
of 30 g of 0.3 µm alumina polishing abrasive and 500 mL of
distilled or deionized water are recommended for this opera-
tion.Additionalweightintheformofastainlesssteelcapmust
be placed on the specimen. The suggested weight to achieve a
satisfactory polish in 30-60 min on a 31.7 mm (1¼-in.)
diameter mount is 350 g.
5.6.2 Samples shall be cleaned with a cotton swab under
FIG. 1 Method of Designing Location of Are
...
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: G209 − 14 G209 − 14 (Reapproved 2018)
Standard Practice for
Detecting mu-phase in Wrought Nickel-Rich, Chromium,
Molybdenum-Bearing Alloys
This standard is issued under the fixed designation G209; 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 practice incorporates etching and metallographic examination of Wrought Nickel-Rich, Chromium, Molybdenum-
Bearing Alloys such as, but not limited to, UNS N06686 and UNS N10276.
1.2 Microstructures have a strong influence on properties and successful application of metals and alloys. The presence of
mu-phase in the microstructure may significantly reduce the corrosion resistance of Wrought Nickel-Rich, Chromium, and
Molybdenum-Bearing Alloys.
1.3 This practice may be used to determine the presence of mu-phase in Wrought Nickel-Rich, Chromium, and Molybdenum-
Bearing Alloys through comparison of microstructure observed for etched metallographic specimens to a glossary of
photomicrographs displaying the presence and absence of mu-phase in the microstructure.
1.4 The values stated in SI units are to be regarded as the standard. Other units are given in parentheses for information only.
1.5 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.
1.6 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
2.1 ASTM Standards:
D1193 Specification for Reagent Water
E3 Guide for Preparation of Metallographic Specimens
E7 Terminology Relating to Metallography
E1245 Practice for Determining the Inclusion or Second-Phase Constituent Content of Metals by Automatic Image Analysis
E1268 Practice for Assessing the Degree of Banding or Orientation of Microstructures
G193 Terminology and Acronyms Relating to Corrosion
3. Terminology
3.1 Definitions:
3.1.1 The terminology used herein, if not specifically defined otherwise, shall be in accordance with Terminology G193.
Definitions provided herein and not given in Terminology G193 are limited only to this practice.
3.1.2 For metallographic definitions used in this practice, refer to Terminology E7.
3.1.3 For evaluation of inclusions, secondary phases and banding, if desired, refer to Practices E1245 and E1268.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 mu-phase (μ), n—rhombohedral phase which may occur in Nickel-Rich, Chromium, Molybdenum-Bearing Alloys and
may occur as coarse, irregular platelets, which form at high temperature.
This test method practice is under the jurisdiction of ASTM Committee G01 on Corrosion of Metals and is the direct responsibility of Subcommittee G01.05 on
Laboratory Corrosion Tests.
Current edition approved Nov. 1, 2014Oct. 1, 2018. Published November 2014November 2018. Originally approved in 2012. Last previous edition approved in 20132014
as G209G209 – 14.–13. DOI: 10.1520/G0209-14.10.1520/G0209-14R18.
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
G209 − 14 (2018)
4. Significance and Use
4.1 These test methods describe laboratory tests to determine the presence of mu-phase in Wrought Nickel-Rich, Chromium,
and Molybdenum-Bearing Alloys through comparison of microstructure observed for etched metallographic specimens to a
glossary of photomicrographs displaying the presence and absence of mu-phase in the microstructure. The presence of mu-phase
in the microstructure may significantly reduce the corrosion resistance, strength, toughness and ductility of Wrought Nickel-Rich,
Chromium, and Molybdenum-Bearing Alloys.
5. Sample Preparation and Etching
5.1 Sectioning:
5.1.1 The selection of test specimens for metallographic examination is extremely important because, if their interpretation is
to be of value, the specimens must be representative of the material that is being studied and shall be per location E (longitudinal
section perpendicular to rolled surface) for plate and sheet and per location G (radial longitudinal section) for rod and bar per Fig.
1 (Guide E3). The intent or purpose of the metallographic examination will usually dictate the location of the specimens to be
studied. For rod and bar test specimens specifically, samples are taken from location G as seen in Fig. 1. Triplicate test specimens
shall be evaluated for determination of the presence of mu-phase.
5.1.2 Cut the specimen to a convenient size using any of various types of silicon carbide, diamond, boron carbide or other
carbide cutoff blades. Deformation damage can be minimized by using thin cutoff wheels 0.78 mm ( ⁄32 in.) thick as opposed to
1.58 mm ( ⁄16 in.). Never cut dry. Use of adequate water coolant is desired to reduce the amount of disturbed metal created, in part,
from frictional heat during this phase of preparation. The original microstructure of a specimen may also be radically altered, (at
least superficially, on the cut surface) due to metallurgical changes if an excessive amount of frictional heat is generated.
5.2 Coarse Grinding—Use a 120 grit silicon carbide (SiC) wet-belt or disk grinder and light contact pressure to obtain a plane
surface free from deep grooves. In addition to producing a flat surface, this procedure removes burred edges or other mechanical
damage which may have occurred during sectioning.
5.3 Mounting—To ensure flatness, and facilitate handling, it is recommended that specimens be mounted in phenolic, acrylic
or cold-setting epoxy resins. Epoxy resins involve the blending of a liquid or powder resin in a suitable hardener to initiate an
exothermic reaction to promote hardening and curing at room temperature. This usually requires an overnight operation. However,
an advantage of epoxy is that the mount is semitransparent and permits observation of all sides of the specimen during each phase
of the preparation. (The advantages and use of acrylic mounting resin are similar to epoxy.) Compression molding techniques may
be used with phenolic powders to produce the standard 31.7-mm (1¼-in.) diameter mounts. Phenolic mounts are convenient when
time constraints do not permit an overnight cold-setting operation.
5.4 Fine Grinding and Polishing—Rotating discs flushed with running water are recommended with successively finer grit
papers of 220, 320, 400, and 600 grit SiC. (A light to medium amount of pressure is exerted on the specimen to minimize the depth
of deformation). Best results are obtained on the 600 SiC paper by grinding the specimen twice. Specimens shall be rotated 90
degrees after each step until the abrasive scratches from the preceding grit have been removed. In each step, the grinding time shall
FIG. 1 Method of Designing Location of Area Shown in Photomicrograph (Guide E3)
Manning, Paul E., Ph.D., Metallographic Preparation of 686 Etching Specimens, Haynes International, Inc., Kokomo, IN, 2011.
G209 − 14 (2018)
be increased to twice as long as that required to remove previous scratches. This ensures removal of disturbed metal from the
previous step. Considerable care shall be used in the fine grinding stage to prevent the formation of artifacts. See Guide E3 for
automated method.
5.5 Rough Polishing—The specimen shall be washed and, preferably, ultrasonically cleaned to ensure the complete removal of
silicon carbide carryover from the fine grinding stage. A napless type cloth shall be charged with 9-μm diamond paste, and water
may be used as the lubricant. The specimen is moved counter to the direction of the rotating polishing wheel from the center to
the outer periphery around the entire lapping surface. Heavy pressure is used with diamond abrasive techniques to gain the
maximum cutting rate. At the conclusion of this stage, the specimen shall again be cleaned to remove any diamond polishing
residue remaining in pinholes, cracks, and cavities.
5.6 Polishing:
5.6.1 Semi-final and final polishing operations on a major portion of metallographic specimens may be completed on vibratory
polishing units. A nylon polishing cloth using a slurry of 30 g of 0.3 μm alumina polishing abrasive and 500 mL of distilled or
deionized water are re
...
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