Standard Test Method for Macroetching Metals and Alloys

SCOPE
1.1 These test procedures describe the methods of macro- etching metals and alloys to reveal their macrostructure.  
1.2 The values stated in inch-pound units are to be regarded as the standard. The SI equivalents of inch-pound units may be approximate.  
1.3 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.  For specific warning statements, see 6.2, 7.1, 8.1.3, 8.2.1, 8.8.3, 8.10.1.1, and 8.13.2.

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Historical
Publication Date
30-Sep-2006
Technical Committee
Current Stage
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ASTM E340-00(2006) - Standard Test Method for Macroetching Metals and Alloys
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: E340 − 00(Reapproved 2006)
Standard Test Method for
1
Macroetching Metals and Alloys
This standard is issued under the fixed designation E340; 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 Department of Defense.
1. Scope and ferrite banding, coring, inclusions, and depth of carburiza-
tion or decarburization. The information provided about varia-
1.1 These test procedures describe the methods of mac-
tions in chemical composition is strictly qualitative but the
roetching metals and alloys to reveal their macrostructure.
location of extremes in segregation will be shown. Chemical
1.2 The values stated in inch-pound units are to be regarded
analyses or other means of determining the chemical compo-
as the standard.The SI equivalents of inch-pound units may be
sition would have to be performed to determine the extent of
approximate.
variation. Macroetching will also show the presence of discon-
1.3 This standard does not purport to address all of the
tinuities and voids, such as seams, laps, porosity, flakes, bursts,
safety concerns, if any, associated with its use. It is the
extrusion rupture, cracks, etc.
responsibility of the user of this standard to establish appro-
3.1.3 Other applications of macroetching in the fabrication
priate safety and health practices and determine the applica-
of metals are the study of weld structure, definition of weld
bility of regulatory limitations prior to use. For specific
penetration, dilution of filler metal by base metals, entrapment
warning statements, see 6.2, 7.1, 8.1.3, 8.2.1, 8.8.3, 8.10.1.1,
of flux, porosity, and cracks in weld and heat affected zones,
and 8.13.2.
etc. It is also used in the heat-treating shop to determine
location of hard or soft spots, tong marks, quenching cracks,
2. Referenced Documents
case depth in shallow-hardening steels, case depth in carbur-
2
2.1 ASTM Standards:
ization of dies, effectiveness of stop-off coatings in
E3 Guide for Preparation of Metallographic Specimens
carburization, etc. In the machine shop, it can be used for the
E381 Method of Macroetch Testing Steel Bars, Billets,
determination of grinding cracks in tools and dies.
Blooms, and Forgings
3.1.4 Macroetchingisusedextensivelyforqualitycontrolin
3. Significance and Use
the steel industry, to determine the tone of a heat in billets with
respect to inclusions, segregation, and structure. Forge shops,
3.1 Applications of Macroetching:
in addition, use macroetching to reveal flow lines in setting up
3.1.1 Macroetching is used to reveal the heterogeneity of
the best forging practice, die design, and metal flow. For an
metals and alloys. Metallographic specimens and chemical
example of the use of macroetching in the steel forging
analyses will provide the necessary detailed information about
industry see Method E381. Forging shops and foundries also
specific localities but they cannot give data about variation
use macroetching to determine the presence of internal faults
from one place to another unless an inordinate number of
and surface defects.The copper industry uses macroetching for
specimens are taken.
control of surface porosity in wire bar. In the aluminum
3.1.2 Macroetching, on the other hand, will provide infor-
industry, macroetching is used to evaluate extrusions as well as
mation on variations in (1) structure, such as grain size, flow
the other products such as forgings, sheets, etc. Defects such as
lines, columnar structure, dendrites, etc.; (2) variations in
chemical composition as evidenced by segregation, carbide coring, cracks, and porthole die welds are identified.
4. Sampling
1
This test method is under the jurisdiction of ASTM Committee E04 on
MetallographyandisthedirectresponsibilityofSubcommitteeE04.01onSpecimen
4.1 As in any method of examination, sampling is very
Preparation.
important. When macroetching is used to solve a problem, the
Current edition approved Oct. 1, 2006. Published October 2006. Originally
ε1
problemitselflargelydictatesthesourceofthesampleastothe
approved in 1968. Last previous edition approved in 2000 as E340 – 00 . DOI:
10.1520/E0340-00R06.
location on the work piece and the stage of manufacture; for
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
example, when looking for pipe, the sample should represent
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
the top of the ingot, or when looking for bursts or flakes, the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website
...

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