ASTM E768-99(2010)e1

Standard Guide for Preparing and Evaluating Specimens for Automatic Inclusion Assessment of Steel

SIGNIFICANCE AND USE
4.1 Inclusion ratings done either manually using Test Methods E45 or automatically using Practice E1122 or E1245 are influenced by the quality of specimen preparation. This guide provides examples of proven specimen preparation methods that retain inclusions in polished steel specimens.  
4.2 This guide provides a procedure to determine if the prepared specimens are of suitable quality for subsequent rating of inclusions. None of these methods should be construed as defining or establishing specific procedures or limits of acceptability for any steel grade.
SCOPE
1.1 This guide2 covers two preparation methods for steel metallographic specimens that will be analyzed for nonmetallic inclusions with automatic image analysis (AIA) equipment. The two methods of preparation are offered as accepted methods used to retain nonmetallic inclusions in steel. This guide does not limit the user to these methods.  
1.2 A procedure to test the suitability of the prepared specimen for AIA inclusion work, using differential interference contrast (DIC), is presented.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

General Information

• Status: Historical
• Publication Date: 31-Oct-2010
• ICS: 77.040.01 - Testing of metals in general
• Technical Committee: E04 - Metallography
• Drafting Committee: E04.01 - Specimen Preparation

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
´1
Designation: E768 − 99 (Reapproved 2010)
Standard Guide for
Preparing and Evaluating Specimens for Automatic
Inclusion Assessment of Steel
This standard is issued under the fixed designation E768; 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.
ε NOTE—Footnote 1 was editorially corrected in May 2016.
1. Scope 2.2 ASTM Adjuncts:
ADJE0768 Differential Interference Contrast Magnification
1.1 This guide covers two preparation methods for steel
100X and 500X (6 micrographs)
metallographicspecimensthatwillbeanalyzedfornonmetallic
inclusions with automatic image analysis (AIA) equipment.
3. Terminology
The two methods of preparation are offered as accepted
3.1 Definitions:
methods used to retain nonmetallic inclusions in steel. This
3.1.1 For definitions used in this practice, refer to Termi-
guide does not limit the user to these methods.
nology E7.
3.1.2 differential interference contrast microscopy—a com-
1.2 A procedure to test the suitability of the prepared
specimen for AIA inclusion work, using differential interfer- prehensive definition appears in Guide E883, paragraph 11.8.
ence contrast (DIC), is presented.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 rigid grinding disk—a non-fabric support surface,
1.3 The values stated in SI units are to be regarded as
such as a composite of metal/ceramic or metal/polymer,
standard. No other units of measurement are included in this
charged with an abrasive (usually 6 to 15-µm diamond
standard.
particles), and used as the fine grinding operation in a metal-
lographic preparation procedure.
2. Referenced Documents
4. Significance and Use
2.1 ASTM Standards:
E3Guide for Preparation of Metallographic Specimens
4.1 Inclusion ratings done either manually usingTest Meth-
E7Terminology Relating to Metallography
ods E45 or automatically using Practice E1122 or E1245 are
E45Test Methods for Determining the Inclusion Content of
influenced by the quality of specimen preparation. This guide
Steel
provides examples of proven specimen preparation methods
E883Guide for Reflected–Light Photomicrography
that retain inclusions in polished steel specimens.
E1122Practice for Obtaining JK Inclusion Ratings Using
4.2 This guide provides a procedure to determine if the
Automatic Image Analysis (Withdrawn 2006)
prepared specimens are of suitable quality for subsequent
E1245Practice for Determining the Inclusion or Second-
rating of inclusions. None of these methods should be con-
Phase Constituent Content of Metals byAutomatic Image
strued as defining or establishing specific procedures or limits
Analysis
of acceptability for any steel grade.
5. Preparation Methods
ThisguideisunderthejurisdictionofASTMCommitteeE04onMetallography
5.1 Background:
and is the direct responsibility of Subcommittee E04.01 on Specimen Preparation.
5.1.1 The inclusions in the plane of polish must be fully
Current edition approved Nov. 1, 2010. Published January 2011. Originally
preserved and clearly visible. Preparation should not produce
approved in 1980. Last previous edition approved in 2005 as E768–99(2005). DOI:
10.1520/E0768-99R10E01.
excessive relief around the perimeter of the inclusions that
Supporting data have been filed atASTM International Headquarters and may
would exaggerate the size and number of inclusions on the
be obtained by requesting Research Report RR:E04-1002.
3 plane of polish. In many cases, the preparation of specimens
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. Acolored plate, consisting of six micrographs that illustrate the use of DIC in
The last approved version of this historical standard is referenced on determining a properly prepared sample (at 100x and 500x), is available from
www.astm.org. ASTM Headquarters. Order Adjuct: ADJE0768.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
E768 − 99 (2010)
TABLE 1 Comparison of ANSI (CAMI) versus FEPA versus
for inclusion rating is more readily performed after the
Median Diameter of Grit Size in Micrometers
specimens have been hardened by a suitable heat treatment
A B C
ANSI (CAMI) FEPA Approximate Median
procedure (austenize, quench to fully martensitic structure,
Diameter
temper at a relatively low temperature).
(µm)
5.1.2 Cleanliness is an important consideration in all stages
60 P60 250
of specimen preparation. 80 P80 180
100 P100 150
5.1.2.1 Heat-treated specimens should be wire brushed or
120 P120 125
shot blasted or have the surface ground to remove adherent
150 P150 90
scale. 180 P180 75
220 P220 63
5.1.2.2 After completing the grinding steps and before
240 P240 58.5
performing the polishing steps, the specimens and specimen
P280 52.2
holders must be cleaned to prevent contamination of the next 280 P320 46.2
320 P360 40.5
preparationstep.Cleaningthespecimensandspecimenholders
P400 35.0
between each grinding step can eliminate contamination of
360 P500 30.2
400 P600 25.8
coarse abrasives to the following finer preparation step.
P800 21.8
5.1.2.3 After the preparation is complete, swab the surface
500 P1000 18.3
carefully with cotton and a water/soap solution containing a
600 P1200 15.3
800 P2400 8.4
corrosion inhibitor such as a machine coolant or ethyl alcohol
D
1200 P4000 3.0
solution to remove any films or other debris that would
A
ANSI - American National Standards Institute
interfere with the inclusion rating.
B
CAMI - Coated Abrasives Manufacturers Institute
5.1.2.4 It is advisable to perform the inclusion analysis as C
FEPA - Federation of European Abrasive Producers
D
soonaspossibleafterpreparationtominimizestainingorother Not a FEPA designation
problems that can affect the analysis.
5.1.3 The two methods that follow have been found to be
reliableproceduresforretaininginclusionsinsteelandachiev-
of steel grades. The relatively low pressures suggested in this
ing the desired results when evaluated by DIC.There are other
procedurewillnotnecessarilyresultinasatisfactorypolishfor
methods that will result in a quality specimen as revealed by
etching and the further evaluation of the specimen’s general
DIC. Each laboratory should develop preparation procedures
microstructure. The pressures used in the following rigid disk
for their materials so that the prepared surfaces meet the
procedure are more likely to result in a surface more satisfac-
requirements presented in 6 of this guide.
tory for revealing general microstructures.
5.1.4 As described in Prractice E3, the specimens may be
5.2.3 Grind the specimens on ANSI 80 grit (P80 FEPA)
sectioned and mounted to ease handling during preparation. It
silicon carbide paper to ensure all sectioning artifacts and
is advisable to use a mounting medium that is hard enough to
deformation damage have been removed and the entire speci-
preserve edges and maintain flatness.
men surface is co-planar to the grinding surface.
5.1.5 Abrasive grit size designations in this guide are
expressedintheAmericanNationalStandardsInstitute(ANSI)
NOTE 2—If the sectioning method resulted in a smooth face and little
or Coated Abrasives Manufacturers Institute (CAMI) system deformation damage, and if after securing the specimens in a fixture for
polishing,theentiresurfaceofinterestisco-planartothegrindingsurface,
units with the corresponding Federation of EuropeanAbrasive
then finer grit papers, such asANSI 180 to 240 (P180 to P240 FEPA) can
Procedure (FEPA) numbers in parentheses. Table 1 provides a
be used for the initial grinding step.
correlation between these two systems and the approximate
5.2.3.1 An adequate flow of water should remove all loos-
median particle diameter for a given grit size in micrometres.
ened abrasive and grinding debris from the paper during the
5.1.6 Most preparation systems apply pressure on the speci-
grinding procedure. The flow of water should ensure the
mens being processed. The best pressure to be used for each
specimen is kept cool during grinding.
preparationstepshouldbedeterminedexperimentally.Conver-
5.2.4 Continue grinding through the sequence of silicon
sions between applied force and pressure are discussed in the
carbide papers listed in Table 2. It may be necessary to clean
Appendix X1.
the samples between every grinding step to prevent contami-
NOTE 1—Care must be taken to protect the polished specimen surface
nation of the next preparation step.
from scratches or contaminants when using a specimen leveling device.
5.2.5 After completing the entire grinding operation, clean
5.2 Silicon Carbide Procedure:
the specimens thoroughly, using ethyl alcohol and cotton, then
5.2.1 A summary of the silicon carbide procedure can be rinse and dry. Ultrasonic cleaning can be used.
found in Table 2.
5.2.5.1 Theuseofasoapandwatersolutioninanultrasonic
5.2.2 When using a semi-automatic polishing equipment, cleaner can attack non-metallic inclusions in some carbon and
grinding and polishing should be performed using approxi-
low alloy steels, leading to an exaggeration in the inclusion’s
mately 18 kPa pressure per specimen. (For a specimen holder apparent size. Adding an inhibitor (such as that used as a
containing six 32-mm mounts, a force of approximately 87 N
machining coolant) may reduce this size exaggeration.
must be applied (see X1.4.2). 5.2.6 Polishthespecimensusing3-µmdiamondabrasiveon
5.2.2.1 Low pressures are recommended to ensure the a low nap cloth, such as woven wool, for 50 s. Clean and dry
retention of an assortment of inclusion types found in a variety the specimens as described in 5.2.5.
´1
E768 − 99 (2010)
TABLE 2 Preparation Method I Silicon Carbide Abrasive Paper Grinding
C
Surface Coolent/ Abrasive Size/Type Time Force Surface Relative Rotation
A B
newtons [lbs]
Lubricant ANSI [FEPA] (seconds) Speed
RPM
Planar Grinding
D
Paper Water 80 [P80] grit SIC 60 14 [2] 300 Complementary
Fine Grinding
Paper Water 120 [P120] grit SIC 14 [2] 300 Complementary
Paper Water 240 [P240] grit SIC 60 14 [2] 300 Complementary
Paper Water 320 [P500] grit SIC 60 14 [2] 300 Complimentary
Paper Water 400 [P600] grit SIC 60 14 [2] 300 C
...

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.
´1
Designation: E768 − 99 (Reapproved 2010) E768 − 99 (Reapproved 2010)
Standard Guide for
Preparing and Evaluating Specimens for Automatic
Inclusion Assessment of Steel
This standard is issued under the fixed designation E768; 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.
ε NOTE—Footnote 1 was editorially corrected in May 2016.
1. Scope
1.1 This guide covers two preparation methods for steel metallographic specimens that will be analyzed for nonmetallic
inclusions with automatic image analysis (AIA) equipment. The two methods of preparation are offered as accepted methods used
to retain nonmetallic inclusions in steel. This guide does not limit the user to these methods.
1.2 A procedure to test the suitability of the prepared specimen for AIA inclusion work, using differential interference contrast
(DIC), is presented.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
2. Referenced Documents
2.1 ASTM Standards:
E3 Guide for Preparation of Metallographic Specimens
E7 Terminology Relating to Metallography
E45 Test Methods for Determining the Inclusion Content of Steel
E883 Guide for Reflected–Light Photomicrography
E1122 Practice for Obtaining JK Inclusion Ratings Using Automatic Image Analysis (Withdrawn 2006)
E1245 Practice for Determining the Inclusion or Second-Phase Constituent Content of Metals by Automatic Image Analysis
2.2 ASTM Adjuncts:
ADJE0768 Differential Interference Contrast Magnification 100X and 500X (6 micrographs)
3. Terminology
3.1 Definitions:
3.1.1 For definitions used in this practice, refer to Terminology E7.
3.1.2 differential interference contrast microscopy—a comprehensive definition appears in Guide E883, paragraph 11.8.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 rigid grinding disk—a non-fabric support surface, such as a composite of metal/ceramic or metal/polymer, charged with
an abrasive (usually 6 to 15-μm diamond particles), and used as the fine grinding operation in a metallographic preparation
procedure.
4. Significance and Use
4.1 Inclusion ratings done either manually using Test Methods E45 or automatically using Practice E1122 or E1245 are
influenced by the quality of specimen preparation. This guide provides examples of proven specimen preparation methods that
retain inclusions in polished steel specimens.
This guide is under the jurisdiction of ASTM Committee E04 on Metallography and is the direct responsibility of Subcommittee E04.01 on Specimen Preparation.
Current edition approved Nov. 1, 2010. Published January 2011. Originally approved in 1999.1980. Last previous edition approved in 2005 as E768–99(2005). DOI:
10.1520/E0768-99R10.
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:E04-1002.
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.
The last approved version of this historical standard is referenced on www.astm.org.
A colored plate, consisting of six micrographs that illustrate the use of DIC in determining a properly prepared sample (at 100x and 500x), is available from ASTM
Headquarters. Order Adjuct: ADJE0768.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
E768 − 99 (2010)
4.2 This guide provides a procedure to determine if the prepared specimens are of suitable quality for subsequent rating of
inclusions. None of these methods should be construed as defining or establishing specific procedures or limits of acceptability for
any steel grade.
5. Preparation Methods
5.1 Background:
5.1.1 The inclusions in the plane of polish must be fully preserved and clearly visible. Preparation should not produce excessive
relief around the perimeter of the inclusions that would exaggerate the size and number of inclusions on the plane of polish. In
many cases, the preparation of specimens for inclusion rating is more readily performed after the specimens have been hardened
by a suitable heat treatment procedure (austenize, quench to fully martensitic structure, temper at a relatively low temperature).
5.1.2 Cleanliness is an important consideration in all stages of specimen preparation.
5.1.2.1 Heat-treated specimens should be wire brushed or shot blasted or have the surface ground to remove adherent scale.
5.1.2.2 After completing the grinding steps and before performing the polishing steps, the specimens and specimen holders must
be cleaned to prevent contamination of the next preparation step. Cleaning the specimens and specimen holders between each
grinding step can eliminate contamination of coarse abrasives to the following finer preparation step.
5.1.2.3 After the preparation is complete, swab the surface carefully with cotton and a water/soap solution containing a
corrosion inhibitor such as a machine coolant or ethyl alcohol solution to remove any films or other debris that would interfere
with the inclusion rating.
5.1.2.4 It is advisable to perform the inclusion analysis as soon as possible after preparation to minimize staining or other
problems that can affect the analysis.
5.1.3 The two methods that follow have been found to be reliable procedures for retaining inclusions in steel and achieving the
desired results when evaluated by DIC. There are other methods that will result in a quality specimen as revealed by DIC. Each
laboratory should develop preparation procedures for their materials so that the prepared surfaces meet the requirements presented
in 6 of this guide.
5.1.4 As described in Prractice E3, the specimens may be sectioned and mounted to ease handling during preparation. It is
advisable to use a mounting medium that is hard enough to preserve edges and maintain flatness.
5.1.5 Abrasive grit size designations in this guide are expressed in the American National Standards Institute (ANSI) or Coated
Abrasives Manufacturers Institute (CAMI) system units with the corresponding Federation of European Abrasive Procedure
(FEPA) numbers in parentheses. Table 1 provides a correlation between these two systems and the approximate median particle
diameter for a given grit size in micrometres.
5.1.6 Most preparation systems apply pressure on the specimens being processed. The best pressure to be used for each
preparation step should be determined experimentally. Conversions between applied force and pressure are discussed in the
Appendix X1.
NOTE 1—Care must be taken to protect the polished specimen surface from scratches or contaminants when using a specimen leveling device.
TABLE 1 Comparison of ANSI (CAMI) versus FEPA versus
Median Diameter of Grit Size in Micrometers
A B C
ANSI (CAMI) FEPA Approximate Median
Diameter
(μm)
60 P60 250
80 P80 180
100 P100 150
120 P120 125
150 P150 90
180 P180 75
220 P220 63
240 P240 58.5
P280 52.2
280 P320 46.2
320 P360 40.5
P400 35.0
360 P500 30.2
400 P600 25.8
P800 21.8
500 P1000 18.3
600 P1200 15.3
800 P2400 8.4
D
1200 P4000 3.0
A
ANSI - American National Standards Institute
B
CAMI - Coated Abrasives Manufacturers Institute
C
FEPA - Federation of European Abrasive Producers
D
Not a FEPA designation
´1
E768 − 99 (2010)
5.2 Silicon Carbide Procedure:
5.2.1 A summary of the silicon carbide procedure can be found in Table 2.
5.2.2 When using a semi-automatic polishing equipment, grinding and polishing should be performed using approximately 18
kPa pressure per specimen. (For a specimen holder containing six 32-mm mounts, a force of approximately 87 N must be applied
(see X1.4.2).
5.2.2.1 Low pressures are recommended to ensure the retention of an assortment of inclusion types found in a variety of steel
grades. The relatively low pressures suggested in this procedure will not necessarily result in a satisfactory polish for etching and
the further evaluation of the specimen’s general microstructure. The pressures used in the following rigid disk procedure are more
likely to result in a surface more satisfactory for revealing general microstructures.
5.2.3 Grind the specimens on ANSI 80 grit (P80 FEPA) silicon carbide paper to ensure all sectioning artifacts and deformation
damage have been removed and the entire specimen surface is co-planar to the grinding surface.
NOTE 2—If the sectioning method resulted in a smooth face and little deformation damage, and if after securing the specimens in a fixture for polishing,
the entire surface of interest is co-planar to the grinding surface, then finer grit papers, such as ANSI 180 to 240 (P180 to P240 FEPA) can be used for
the initial grinding step.
5.2.3.1 An adequate flow of water should remove all loosened abrasive and grinding debris from the paper during the grinding
procedure. The flow of water should ensure the specimen is kept cool during grinding.
5.2.4 Continue grinding through the sequence of silicon carbide papers listed in Table 2. It may be necessary to clean the
samples between every grinding step to prevent contamination of the next preparation step.
5.2.5 After completing the entire grinding operation, clean the specimens thoroughly, using ethyl alcohol and cotton, then rinse
and dry. Ultrasonic cleaning can be used.
5.2.5.1 The use of a soap and water solution in an ultrasonic cleaner can attack non-metallic inclusions in some carbon and low
alloy steels, leading to an exaggeration in the inclusion’s apparent size. Adding an inhibitor (such as that used as a machining
coolant) may reduce this size exaggeration.
5.2.6 Polish the specimens using 3-μm diamond abrasive on a low nap cloth, such as woven wool, for 50 s. Clean and dry the
specimens as described in 5.2.5.
5.2.7 Polish the specimens using a 1-μm diamond abrasive on a high nap cloth for 50 s. Clean and dry the specimens as
described in 5.2.5.
5.2.8 A final manual polishing step may be added, using 0.25-μm diamond abrasive on a low nap cloth for 10 to 20 s, using
relatively high pressure. Clean and dry the specimens as described in 5.2.5.
5.2.8.1 Ultrasonic cleaning is not recommended after the final manual or automatic polis
...