ASTM E45-18a(2023)
(Test Method)Standard Test Methods for Determining the Inclusion Content of Steel
Standard Test Methods for Determining the Inclusion Content of Steel
SIGNIFICANCE AND USE
4.1 These test methods cover four macroscopic and five microscopic test methods (manual and image analysis) for describing the inclusion content of steel and procedures for expressing test results.
4.2 Inclusions are characterized by size, shape, concentration, and distribution rather than chemical composition. Although compositions are not identified, Microscopic methods place inclusions into one of several composition-related categories (sulfides, oxides, and silicates—the last as a type of oxide). Paragraph 11.1.1 describes a metallographic technique to facilitate inclusion discrimination. Only those inclusions present at the test surface can be detected.
4.3 The macroscopic test methods evaluate larger surface areas than microscopic test methods and because examination is visual or at low magnifications, these methods are best suited for detecting larger inclusions. Macroscopic methods are not suitable for detecting inclusions smaller than about 0.40 mm (1/64 in.) in length and the methods do not discriminate inclusions by type.
4.4 The microscopic test methods are employed to characterize inclusions that form as a result of deoxidation or due to limited solubility in solid steel (indigenous inclusions). As stated in 1.1, these microscopic test methods rate inclusion severities and types based on morphological type, that is, by size, shape, concentration, and distribution, but not specifically by composition. These inclusions are characterized by morphological type, that is, by size, shape, concentration, and distribution, but not specifically by composition. The microscopic methods are not intended for assessing the content of exogenous inclusions (those from entrapped slag or refractories). In case of a dispute whether an inclusion is indigenous or exogenous, microanalytical techniques such as energy dispersive X-ray spectroscopy (EDS) may be used to aid in determining the nature of the inclusion. However, experience and knowledge of the casting proce...
SCOPE
1.1 These test methods cover a number of recognized procedures for determining the nonmetallic inclusion content of wrought steel. Macroscopic methods include macroetch, fracture, step-down, and magnetic particle tests. Microscopic methods include five generally accepted systems of examination. In these microscopic methods, inclusions are assigned to a category based on similarities in morphology, and not necessarily on their chemical identity. Metallographic techniques that allow simple differentiation between morphologically similar inclusions are briefly discussed. While the methods are primarily intended for rating inclusions, constituents such as carbides, nitrides, carbonitrides, borides, and intermetallic phases may be rated using some of the microscopic methods. In some cases, alloys other than steels may be rated using one or more of these methods; the methods will be described in terms of their use on steels.
1.2 These test methods cover procedures to perform JK-type inclusion ratings using automatic image analysis in accordance with microscopic methods A and D.
1.3 Depending on the type of steel and the properties required, either a macroscopic or a microscopic method for determining the inclusion content, or combinations of the two methods, may be found most satisfactory.
1.4 These test methods deal only with recommended test methods and nothing in them should be construed as defining or establishing limits of acceptability for any grade of steel.
1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.
1.6 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...
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Standards Content (Sample)
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.
Designation: E45 − 18a (Reapproved 2023)
Standard Test Methods for
Determining the Inclusion Content of Steel
This standard is issued under the fixed designation E45; 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 1.7 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 These test methods cover a number of recognized
ization established in the Decision on Principles for the
procedures for determining the nonmetallic inclusion content
Development of International Standards, Guides and Recom-
of wrought steel. Macroscopic methods include macroetch,
mendations issued by the World Trade Organization Technical
fracture, step-down, and magnetic particle tests. Microscopic
Barriers to Trade (TBT) Committee.
methods include five generally accepted systems of examina-
tion. In these microscopic methods, inclusions are assigned to
2. Referenced Documents
a category based on similarities in morphology, and not
2.1 ASTM Standards:
necessarily on their chemical identity. Metallographic tech-
E3 Guide for Preparation of Metallographic Specimens
niques that allow simple differentiation between morphologi-
E7 Terminology Relating to Metallography
cally similar inclusions are briefly discussed. While the meth-
E381 Method of Macroetch Testing Steel Bars, Billets,
ods are primarily intended for rating inclusions, constituents
Blooms, and Forgings
such as carbides, nitrides, carbonitrides, borides, and interme-
E709 Guide for Magnetic Particle Testing
tallic phases may be rated using some of the microscopic
E768 Guide for Preparing and Evaluating Specimens for
methods. In some cases, alloys other than steels may be rated
Automatic Inclusion Assessment of Steel
using one or more of these methods; the methods will be
E1245 Practice for Determining the Inclusion or Second-
described in terms of their use on steels.
Phase Constituent Content of Metals by Automatic Image
1.2 These test methods cover procedures to perform JK-type
Analysis
inclusion ratings using automatic image analysis in accordance
E1444/E1444M Practice for Magnetic Particle Testing for
with microscopic methods A and D.
Aerospace
1.3 Depending on the type of steel and the properties
E1951 Guide for Calibrating Reticles and Light Microscope
required, either a macroscopic or a microscopic method for
Magnifications
determining the inclusion content, or combinations of the two
2.2 SAE Standards:
methods, may be found most satisfactory.
J422, Recommended Practice for Determination of Inclu-
sions in Steel
1.4 These test methods deal only with recommended test
methods and nothing in them should be construed as defining 2.3 Aerospace Material Specifications:
or establishing limits of acceptability for any grade of steel. AMS 2300, Premium Aircraft-Quality Steel Cleanliness:
Magnetic Particle Inspection Procedure
1.5 The values stated in SI units are to be regarded as
AMS 2301, Aircraft Quality Steel Cleanliness: Magnetic
standard. The values given in parentheses after SI units are
Particle Inspection Procedure
provided for information only and are not considered standard.
AMS 2303, Aircraft Quality Steel Cleanliness: Martensitic
1.6 This standard does not purport to address all of the
Corrosion-Resistant Steels Magnetic Particle Inspection
safety concerns, if any, associated with its use. It is the
Procedure
responsibility of the user of this standard to establish appro-
AMS 2304, Special Aircraft-Quality Steel Cleanliness: Mag-
priate safety, health, and environmental practices and deter-
netic Particle Inspection Procedure
mine the applicability of regulatory limitations prior to use.
1 2
These test methods are under the jurisdiction of ASTM Committee E04 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Metallography and is the direct responsibility of Subcommittee E04.09 on Inclu- contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
sions. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Nov. 1, 2023. Published November 2023. Originally the ASTM website.
approved in 1942. Last previous edition approved in 2018 as E45 –18a. DOI: Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale,
10.1520/E0045-18AR23. PA 15096-0001, http://www.sae.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E45 − 18a (2023)
2.4 ISO Standards: 4. Significance and Use
ISO 3763, Wrought Steels—Macroscopic Methods for As-
4.1 These test methods cover four macroscopic and five
sessing the Content of Nonmetallic Inclusions
microscopic test methods (manual and image analysis) for
ISO 4967, Steel—Determination of Content of Nonmetallic
describing the inclusion content of steel and procedures for
Inclusions—Micrographic Methods Using Standard Dia-
expressing test results.
grams
4.2 Inclusions are characterized by size, shape,
2.5 ASTM Adjuncts:
5 concentration, and distribution rather than chemical composi-
Inclusions in Steel Plates I-A and II
tion. Although compositions are not identified, Microscopic
Four Photomicrographs of Low Carbon Steel
methods place inclusions into one of several composition-
related categories (sulfides, oxides, and silicates—the last as a
3. Terminology
type of oxide). Paragraph 11.1.1 describes a metallographic
3.1 Definitions:
technique to facilitate inclusion discrimination. Only those
3.1.1 For definitions of terms used in these test methods, see
inclusions present at the test surface can be detected.
Terminology E7.
4.3 The macroscopic test methods evaluate larger surface
3.1.2 Terminology E7 includes the term inclusion count;
areas than microscopic test methods and because examination
since some methods of these test methods involve length
is visual or at low magnifications, these methods are best suited
measurements or conversions to numerical representations of
for detecting larger inclusions. Macroscopic methods are not
lengths or counts, or both, the term inclusion rating is
suitable for detecting inclusions smaller than about 0.40 mm
preferred.
( ⁄64 in.) in length and the methods do not discriminate
3.2 Definitions of Terms Specific to This Standard:
inclusions by type.
3.2.1 aspect ratio—the length-to-width ratio of a micro-
structural feature.
4.4 The microscopic test methods are employed to charac-
terize inclusions that form as a result of deoxidation or due to
3.2.2 discontinuous stringer—three or more Type B or C
limited solubility in solid steel (indigenous inclusions). As
inclusions aligned in a plane parallel to the hot working axis
stated in 1.1, these microscopic test methods rate inclusion
and offset by no more than 15 μm, with a separation of less than
severities and types based on morphological type, that is, by
40 μm (0.0016 in.) between any two nearest neighbor inclu-
size, shape, concentration, and distribution, but not specifically
sions.
by composition. These inclusions are characterized by morpho-
3.2.3 inclusion types—for definitions of sulfide-, alumina-,
logical type, that is, by size, shape, concentration, and
and silicate-type inclusions, see Terminology E7. Globular
distribution, but not specifically by composition. The micro-
oxide, in some methods refers to isolated, relatively nonde-
scopic methods are not intended for assessing the content of
formed inclusions with an aspect ratio not in excess of 2:1. In
exogenous inclusions (those from entrapped slag or refracto-
other methods, oxides are divided into deformable and nonde-
ries). In case of a dispute whether an inclusion is indigenous or
formable types.
exogenous, microanalytical techniques such as energy disper-
3.2.4 JK inclusion rating—a method of measuring nonme-
sive X-ray spectroscopy (EDS) may be used to aid in deter-
tallic inclusions based on the Swedish Jernkontoret procedures;
mining the nature of the inclusion. However, experience and
Methods A and D of these test methods are the principal JK
knowledge of the casting process and production materials,
rating methods, and Method E also uses the JK rating charts.
such as deoxidation, desulfurization, and inclusion shape
3.2.5 stringer—an individual inclusion that is highly elon- control additives as well as refractory and furnace liner
compositions must be employed with the microanalytical
gated in the deformation direction or three or more Type B or
C inclusions aligned in a plane parallel to the hot working axis results to determine if an inclusion is indigenous or exogenous
and offset by no more than 15 μm, with a separation of less than
4.5 Because the inclusion population within a given lot of
40 μm (0.0016 in.) between any two nearest neighbor inclu-
steel varies with position, the lot must be statistically sampled
sions.
in order to assess its inclusion content. The degree of sampling
3.2.6 threshold setting—isolation of a range of gray level
must be adequate for the lot size and its specific characteristics.
values exhibited by one constituent in the microscope field.
Materials with very low inclusion contents may be more
accurately rated by automatic image analysis, which permits
3.2.7 worst-field rating—a rating in which the specimen is
more precise microscopic ratings.
rated for each type of inclusion by assigning the value for the
highest severity rating observed of that inclusion type any-
4.6 Results of macroscopic and microscopic test methods
where on the specimen surface.
may be used to qualify material for shipment, but these test
methods do not provide guidelines for acceptance or rejection
purposes. Qualification criteria for assessing the data devel-
oped by these methods can be found in ASTM product
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org.
standards or may be described by purchaser-producer agree-
Available from ASTM International Headquarters. Order Adjunct No.
ments. By agreements between producer and purchaser, these
ADJE004502A. Original adjunct produced in 1983. Adjunct revised in 2011.
test methods may be modified to count only certain inclusion
Available from ASTM International Headquarters. Order Adjunct No.
ADJE004501. Original adjunct produced in 1983. types and thicknesses, or only those inclusions above a certain
E45 − 18a (2023)
severity level, or both. Also, by agreement, qualitative prac- method for fracture surface inclusion ratings. In some
tices may be used where only the highest severity ratings for instances, indications as small as 0.40 mm ( ⁄64 in.) in length
are recorded.
each inclusion type and thickness are defined or the number of
fields containing these highest severity ratings are tabulated. 5.1.3 Step-Down Method—The step-down test method is
used to determine the presence of inclusions on machined
4.7 These test methods are intended for use on wrought
surfaces of rolled or forged steel. The test sample is machined
metallic structures. While a minimum level of deformation is
to specified diameters below the surface and surveyed for
not specified, the test methods are not suitable for use on cast
inclusions under good illumination with the unaided eye or
structures or on lightly worked structures.
with low magnification. In some instances, test samples are
machined to smaller diameters for further examination after the
4.8 Guidelines are provided to rate inclusions in steels
original diameters are inspected. This test is essentially used to
treated with rare earth additions or calcium-bearing com-
determine the presence of inclusions 3 mm ( ⁄8 in.) in length
pounds. When such steels are evaluated, the test report should
and longer.
describe the nature of the inclusions rated according to each
5.1.4 Magnetic Particle Method—The magnetic particle
inclusion category (A, B, C, D).
method is a variation of the step-down method for ferromag-
4.9 In addition to the Test Methods E45 JK ratings, basic
netic materials in which the test sample is machined,
(such as used in Practice E1245) stereological measurements
magnetized, and magnetic powder is applied. Discontinuities
(for example, the volume fraction of sulfides and oxides, the
as small as 0.40 mm ( ⁄64 in.) in length create magnetic leakage
number of sulfides or oxides per square millimeter, the spacing
fields that attract the magnetic powder, thereby outlining the
between inclusions, and so forth) may be separately deter-
inclusion. See Practice E1444/E1444M and Guide E709 on
mined and added to the test report, if desired for additional
magnetic particle examinations for more details of the proce-
information. This practice, however, does not address the
dure. Refer to Aerospace Materials Specifications AMS 2300,
measurement of such parameters.
AMS 2301, AMS 2303, and AMS 2304.
5.2 Advantages:
MACROSCOPIC METHODS
5.2.1 These test methods facilitate the examination of speci-
mens with large surface areas. The larger inclusions in steel,
5. Macroscopical Test Methods Overview which are the main concern in most cases, are not uniformly
distributed and the spaces between them are relatively large, so
5.1 Summary:
that the chances of revealing them are better when larger
5.1.1 Macro-etch Test—The macro-etch test is used to
specimens are examined.
indicate inclusion content and distribution, usually in the cross
5.2.2 Specimens for macroscopic examination may be
section or transverse to the direction of rolling or forging. In
quickly prepared by machining and grinding. A highly polished
some instances, longitudinal sections are also examined. Tests
surface is not necessary. The macroscopic methods are suffi-
are prepared by cutting and machining a section through the
ciently sensitive to reveal the larger inclusions.
desired area and etching with a suitable reagent. A solution of
5.3 Disadvantages:
one part hydrochloric acid and one part water at a temperature
5.3.1 These test methods do not distinguish among the
of 71 °C to 82 °C (160 °F to 180°F) is widely used. As the
different inclusion shapes.
name of this test implies, the etched surface is examined
5.3.2 They are not suitable for the detection of small
visually or at l
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