ASTM E381-01
(Test Method)Standard Method of Macroetch Testing Steel Bars, Billets, Blooms, and Forgings
Standard Method of Macroetch Testing Steel Bars, Billets, Blooms, and Forgings
SCOPE
1.1 Macroetching, which is the etching of specimens for macrostructural examination at low magnifications, is a frequently used technique for evaluating steel products such as bars, billets, blooms, and forgings.
1.2 Included in this method is a procedure for rating steel specimens by a graded series of photographs showing the incidence of certain conditions. The method is limited in application to bars, billets, blooms, and forgings of carbon and low alloy steels.
1.3 A number of different etching reagents may be used depending upon the type of examination to be made. Steels react differently to etching reagents because of variations in chemical composition, method of manufacture, heat treatment and many other variables. Establishment of general standards for acceptance or rejection for all conditions is impractical as some conditions must be considered relative to the part in which it occurs.
1.4 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. See the specific precautionary statement in 5.3.
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Designation: E 381 – 01
Standard Method of
Macroetch Testing Steel Bars, Billets, Blooms, and
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Forgings
This standard is issued under the fixed designation E 381; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 3. Terminology
1.1 Macroetching, which is the etching of specimens for 3.1 Definitions—For definitions of terms used in this
macrostructural examination at low magnifications, is a fre- method, see Terminology E 7.
quently used technique for evaluating steel products such as 3.2 Definitions of Terms Specific to This Standard:
bars, billets, blooms, and forgings. 3.2.1 Terminology Applicable Only to Ingot Cast Product:
1.2 Included in this method is a procedure for rating steel 3.2.1.1 splash—a nonuniform etch pattern where
specimens by a graded series of photographs showing the irregularly-shaped areas exhibit a different etch contrast than
incidence of certain conditions. The method is limited in surrounding areas. Splash is normally associated with molten
application to bars, billets, blooms, and forgings of carbon and steel which solidifies and oxidizes during initial pouring and
low alloy steels. which is not completely redissolved by the remaining molten
1.3 A number of different etching reagents may be used steel.
depending upon the type of examination to be made. Steels 3.2.1.2 butt tears—subsurface cracks normally parallel to
react differently to etching reagents because of variations in the surface of the ingot mold wall.
chemical composition, method of manufacture, heat treatment 3.2.1.3 flute cracks—cracks perpendicular to the surface of
and many other variables. Establishment of general standards the ingot mold wall which may, or may not, extend to the
for acceptance or rejection for all conditions is impractical as surface of the product.
some conditions must be considered relative to the part in 3.2.1.4 burst—a single or multi-rayed crack normally lo-
which it occurs. cated at the center of the wrought product.
1.4 This standard does not purport to address all of the 3.2.2 Definitions Applicable Only to Continuously Cast
safety concerns, if any, associated with its use. It is the Products:
responsibility of the user of this standard to establish appro- 3.2.2.1 chill zone—rapidly cooled metal with a fine struc-
priate safety and health practices and determine the applica- ture at the surface of the product which is normally continuous
bility of regulatory limitations prior to use. See the specific around that surface.
precautionary statement in 5.3. 3.2.2.2 chill zone crack—any crack which is located par-
tially or completely in the chill zone and may extend to the
2. Referenced Documents
surface of the product.
2.1 ASTM Standards: 3.2.2.3 diagonal crack—a crack which lies completely or
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E 7 Terminology Relating to Metallography
partially in the diagonal regions of a non-round product where
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E 340 Test Method for Macroetching Metals and Alloys adjacent columnar or dendritic growth patterns intersect.
E 1180 Practice for Preparing Sulfur Prints for Macrostruc-
3.2.2.4 subsurface crack—a crack perpendicular to and just
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tural Examination beneath the chill zone.
2.2 ASTM Adjuncts:
3.2.2.5 mid-radius crack—a crack perpendicular to the
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Photographs for Rating Macroetched Steel (3 plates) surface of the product located approximately halfway between
the surface and center of the product.
3.2.2.6 center crack—a crack with an aspect ratio (length/
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This method is under the jurisdiction of ASTM Committee E04 on Metallog-
width) of approximately 3 or greater located at, or near, the
raphy, and is the direct responsibility of Subcommittee E04.01 on Sampling,
center of the product.
Specimen Preparation, and Photography.
Current edition approved April 10, 2001. Published May 2001. Originally 3.2.2.7 star crack—a star-shaped or multi-rayed crack at the
published as E 381 – 68. Last previous edition E 381 – 98.
center of the product.
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Annual Book of ASTM Standards, Vol 03.01.
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Available from ASTM Headquarters. Order Adjunct: ADJE038101 (Plate I),
ADJE038102 (Plate II), and ADJE038103 (Plate III).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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E 381
3.2.2.8 scattered porosity—multiple round or irregularly- 4. Significance and Use
shaped pores uniformly distributed about the central portion of
4.1 Macroetching is used in the steel industry because it is
the product.
a simple test th
...
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