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: E340 − 23

Standard Practice for

Macroetching Metals and Alloys1
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 U.S. Department of Defense.

1. Scope 3.1.1 Macroetching is used to reveal the heterogeneity of

1.1 These procedures describe the methods of macroetching metals and alloys. Metallographic specimens and chemical
metals and alloys to reveal their macrostructure. analyses will provide the necessary detailed information about
specific localities, but they cannot give data about variation
1.2 The values stated in inch-pound units are to be regarded from one place to another unless an inordinate number of
as standard. The values given in parentheses are mathematical specimens are taken.
conversions to the International System (SI) units that are 3.1.2 Macroetching, on the other hand, will provide infor-
provided for information only and are not considered standard. mation on variations in (1) structure, such as grain size, flow
1.3 This standard does not purport to address all of the lines, columnar structure, dendrites, and so forth; (2) variations
safety concerns, if any, associated with its use. It is the in chemical composition as evidenced by segregation, carbide
responsibility of the user of this standard to establish appro- and ferrite banding, coring, inclusions, and depth of carburiza-
priate safety, health, and environmental practices and deter- tion or decarburization. The information provided about varia-

iTeh Standards
mine the applicability of regulatory limitations prior to use.For tions in chemical composition is strictly qualitative but the
specific warning statements, see 6.2, 7.1, 8.1.3, 8.2.1, 8.8.3, location of extremes in segregation will be shown. Chemical
8.10.1.1, and 8.13.2. It is further recommended to review the analyses or other means of determining the chemical compo-
guidance in Guide E2014.
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1.4 This international standard was developed in accor-
sition would have to be performed to determine the extent of
variation. Macroetching will also show the presence of discon-

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dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
tinuities and voids, such as seams, laps, porosity, flakes, bursts,
extrusion rupture, cracks, and so forth.
Development of International Standards, Guides and Recom- 3.1.3 Other applications of macroetching in the fabrication
mendations issued by the World Trade Organization Technical of metals are the study of weld structure, definition of weld
Barriers to Trade (TBT) Committee. ASTM E340-23 penetration, dilution of filler metal by base metals, entrapment
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of flux, porosity, and cracks in weld and heat affected zones,
2. Referenced Documents and so forth. It is also used in the heat-treating shop to
2.1 ASTM Standards: 2 determine location of hard or soft spots, tong marks, quenching
E3 Guide for Preparation of Metallographic Specimens cracks, case depth in shallow-hardening steels, case depth in
E381 Method of Macroetch Testing Steel Bars, Billets, carburization, effectiveness of stop-off coatings in
Blooms, and Forgings carburization, and so forth. In the machine shop, it can be used
E2014 Guide on Metallographic Laboratory Safety for the determination of grinding cracks in tools and dies.
3.1.4 Macroetching is used extensively for quality control in
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
the best forging practice, die design, and metal flow. For an
example of the use of macroetching in the steel forging
1
This test method is under the jurisdiction of ASTM Committee E04 on industry see Method E381. Forging shops and foundries also
Metallography and is the direct responsibility of Subcommittee E04.01 on Specimen use macroetching to determine the presence of internal faults
Preparation.
Current edition approved Nov. 15, 2023. Published November 2023. Originally and surface defects. The copper industry uses macroetching for
approved in 1968. Last previous edition approved in 2015 as E340 – 15. DOI: control of surface porosity in wire and bar. In the aluminum
10.1520/E0340-23.
2
industry, macroetching is used to evaluate extrusions as well as
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
the other products such as forgings, sheets, and so forth.
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 Defects such as coring, cracks, and porthole die welds are
the ASTM website. identified.

Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States

1
 E340 − 23
4. Sampling structure, and so forth. Careful preparation is usually rewarded
4.1 As in any method of examination, sampling is very with highly detailed structures giving a large amount of
important. When macroetching is used to solve a problem, the information. Welds involving dissimilar metals will produce
problem itself largely dictates the source of the sample as to the problems in etching. The best method is to etch the least
location on the work piece and the stage of manufacture; for corrosion-resistant portion first and the more resistant portion
example, when looking for pipe, the sample should represent afterwards. Occasionally, an intermediary etchant may be
the top of the ingot, or when looking for bursts or flakes, the required. The boundaries between etched and unetched portion
sample should be taken as soon after hot working as possible. will give an idea of weld penetration and dilution.
4.5.4 Castings—Cut the specimen to display the defect or
4.2 When macroetching is used as an inspection procedure, feature being sought.
sampling ought to be done in an early stage of manufacturing 4.5.5 Machined and Ground Parts—When looking for
so that, if the material proves faulty, no wasteful unnecessary grinding cracks, and so forth, the surface itself is used as a
work is done. However, the sample should not be taken so sample. Because the machined or ground part is often the
early that further working can introduce serious defects. In the finished part, it may be undesirable to immerse the part in acid.
steel industry, for example, the sample is usually taken after In this case, other methods such as dye penetrant methods may
ingot breakdown and after most chances of bursts or flakes be more desirable.
occurring have passed. Billets or blooms going into small sizes
are sampled after initial breakdown. Material going into 5. Preparation
forging billets or die blocks is sampled near the desired finish 5.1 Sample preparation need not be elaborate. Any method
size. Sampling may be done systematically or on a random of presenting a smooth surface with a minimum amount of cold
basis. work will be satisfactory. Disks may be faced on a lathe or a
4.3 Samples may be cold cut from the source by any shaper. The usual procedure is to take a roughing cut, then a
convenient method; saws and abrasive cutoff wheels are finish cut. This will generate a smooth surface and remove cold
particularly effective. Torch cutting or hot cutting should be work from prior operations. Sharp tools are necessary to
used only when necessary to cut a sample from a large piece. produce a good specimen. Grinding is usually conducted in the

iTeh Standards
The sample then is sectioned well away from the hot-cut
surface. An example of permissible use of torch cutting is the
same manner, using free-cutting wheels and light finishing
cuts. When fine detail is required, the specimen should be

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excising of a piece from a large plate and then cutting a sample ground down through the series of metallographic papers (see
for macroetching 4 in. to 5 in. (102 mm to 127 mm) away from Guide E3). Where necessary, details are given in Tables 1-14.
the torch-cut edge. 5.2 Care should be taken to examine the surface before and
Document
4.4 Some common methods of sampling,
are as follows:
listed by source, Preview
after etching to ensure induced damage from surface prepara-
tion does not interfere with analysis. Specific guidance is
included in the following sections.
4.5 Billets, Blooms, and Hot-Rolled Products—Disks are
usually cut from these products near the end. Samples ASTM E340-23
cut too 5.3 After surface preparation, the sample is cleaned care-
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close to the end, however, may have false structures because of fully with suitable solvents. Any grease, oil, or other residue
fish-tailing. Disks from large blooms are sometimes cut into will produce an uneven etch response. Once cleaned, care
smaller pieces for ease in handling. should be taken not to touch the sample surface or contaminate
4.5.1 Forgings and Extrusions—Disks cut transverse to the it in any way.
long dimension will show flakes, bursts, and so forth. Forgings 6. Solutions
may also be cut parallel to the long dimension to show flow
lines. In complicated forgings, some thought will have to be 6.1 The solutions used for macroetching are given in the
given to the proper method of cutting so as to show flow lines. tables listed under each alloy. In most cases a laboratory grade
Macroetching of an unprepared specimen will show surface of reagent should be used. Technical grades may provide
defects such as shuts, flats, seams, and so forth. In extrusions, satisfactory results. The solution should be clean and clear, free
coring and coarse grain are more commonly found in the back of suspended particles, scum, and so forth. Solutions may lose
end of the extrusion. effectiveness through age or reuse, and should be replaced if
4.5.2 Sheets and Plates—A sufficiently large sample should not performing consistently.
be taken when looking for surface defects. An ideal length 6.2 Caution must be observed in mixing. Many of the
would be the circumference of the last roll, but this may be etchants are strong acids. In all cases, the various chemicals
inconveniently long. Several samples totaling some given should be added slowly to the water or solvent while stirring.
fraction of the circumference can be used; however, there is In the cases where hydrofluoric acid is used, the solution
always a chance then that a defect arising from faulty rolls should be mixed and used in polyethylene vessels.
would not be detected. When seeking information on (Warning—Hydrofluoric acid must not be allowed to contact
laminations, a transverse section is used. In many cases, the skin.)
however, to reduce the size of the specimen, only a section out
of the center of the plate may be taken. 7. Procedure
4.5.3 Weldments—A disk cut perpendicular to the direction 7.1 Many of the solutions are aggressive and may give off
of welding will show weld penetration, heat affected zone, irritating and corrosive fumes. Etching should be done in a

2
 E340 − 23
TABLE 1 Macroetchants for Aluminum and Aluminum Alloys
Alloy Composition Procedure Comments
All NaOH 10 g Immerse sample 5 min to 15 min in solution heated to Good general-purpose etchant, can be
H2O 100 mL 140 °F to 160 °F (60°C to 70 °C). Rinse in water, and used on almost all aluminum alloys.
remove smut in strong HNO3 solution. Rinse and Does not require fine grinding.
repeat etching if necessary.

3XXX HCl (concentrated) 75 mL Mix fresh before using. Use at room temperature. May Used to develop grain structure. May be
4XXX HNO3 (concentrated) 25 mL be used as immersion etch or swabbed over diluted with 25 % water to slow down
5XXX HF (48 %) 5 mL specimen surface. Rinse specimen in warm water and etching. Does not require fine grinding.
6XXX dry.
High Si castings

High purity A1 HCl (concentrated) 45 mL Immerse specimen at room temperature until desired Tucker’s etch. General purpose etch for
1XXX HNO3 (concentrated) 15 mL contrast is developed. Rinse in warm water and dry. revealing microstructure of both cast and
3XXX HF (48 %) 15 mL wrought aluminum. Does not require fine
4XXX H2O 25 mL grinding.
5XXX
6XXX

All except high Si HCl (concentrated) 15 mL Same as above. 1 + 2 Tucker’s. Same as above, but
castings HNO3 (concentrated) 5 mL slower acting.
HF (48 %) 5 mL
H2O 75 mL

2XXX HCl (concentrated) 15 mL May be used as an immersion etch or swabbed over Flick’s reagent. Best results are obtained
High Cu alloys HF (48 %) 10 mL the specimen surface. When desired contrast is with a ground surface. 180 grit will
H2O 90 mL obtained, rinse in water and remove deposits with suffice.
concentrated HNO3. Rinse in warm water and dry.

TABLE 2 Macroetchants for Beryllium and Beryllium Alloys

Metal
Be HCl
Composition
10 mL
iTeh Standards Procedure
Either swab or immerse at room temperature for a few
Comments
Works best on coarse grained Be.

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NH4Cl 4g minutes, rinse in water and dry.
H 2O 90 mL

Be HCl 10 mL As above. An alternative when No. 1 does not work. Fine-grained

NH4Cl
Picric acid
H 2O
2g
2g
90 mL
Document Preview metal may not give good results in either case.

ASTM E340-23
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TABLE 3 Macroetchants for Cobalt and Cobalt Alloys
Alloy Composition Procedure Comments
49Co-49Fe-V HCl 50 mL Immerse specimen in hot solution (140 to 180°F) for General structure,
Some Co-Cr alloys H2O 50 mL 30 to 60 min. Rinse in hot water and dry. porosity.

25Cr-10Ni-8W HCl 50 mL Swab until desired contrast is obtained then rinse in Grain size, general
21Cr-20Ni- HNO3 10 mL warm water and dry. structure.
3W-3Mo-1Cb FeCl3 10 g
H2O 100 mL

18Cr-10Ni-14W CuCl2 ·2NH4 Cl·2H2O 2g As above. As above.

FeCl3 5g
HNO3 5 mL
HCl 50 mL
H2 O 80 m

well-ventilated room, preferably under a fume hood. The required, dip the specimen into a second solution. After rinsing
solution should be mixed and placed in a corrosion resistant the specimen with hot water, blow dry with clean compressed
tray or dish and brought to the operating temperature. The air.
specimen or specimens should be placed in a tray of stainless
steel screen or on some non-reactive support. Glass rods often 7.2 In the case of large specimens, such as ingot sections,
are placed on the bottom of the acid container and the swabbing may be the only practical method of macroetching.
specimens laid directly on the rods. When etching is Saturate a large wad of cotton held in stainless steel or nickel
completed, remove the specimens from the dish taking great tongs with the etchant and sweep over the surface of the
care not to touch the etched surface. When desmutting is specimen. An effort should be made to wet the entire surface as

3
 E340 − 23
TABLE 4 Macroetchants for Copper and Copper Alloys
Alloys Composition Procedure Comments
Cu and all brasses HNO3 10 mL Immerse specimen in solution at room temperature Emphasize grains and cracks.
H2 O 90 mL for a few minutes. Rinse in water and dry.

Cu and all brasses HNO3 50 mL As above. Brings out grain contrast, pits result
H2 O 50 mL unless agitated. Aluminum bronzes may
form smut which can be removed by brief
immersion in concentrated HNO3.

Cu and all brasses HCl 30 mL As above. Good grain contrast.

FeCl3 10 g
H2O or ethanol 120 mL

Cu, high Cu alloys, K2Cr2O7 sat 2g Immerse specimen in solution at room temperature Emphasizes grain boundaries and oxide
phosphorus, tin soln of NaCl for 15 to 30 min then swab with fresh solution. inclusions.
bronzes H2SO3 Rinse in warm water and dry.
H2 O

All HNO3 50 mL Immerse specimen in solution at room temperature. Brilliant deep etch.
AgNO3 5g Rinse in warm water and dry.
H2 O 50 mL

Brass 20 % CH3COOH 20 mL As above. Strain lines.

5 % H2CrO4 10 mL
10 % FeCl3 in H2O 5 mL

Silicon brass or bronze CrO3 40 g Immerse specimen in solution at room temperature,

NH4Cl 7.5 g rinse in warm water and dry.
HNO3 (concentrated) 50 mL
H2SO4 (concentrated) 8 mL
H2O 100 mL

iTeh Standards
soon as possible. After the initial wetting, keep the swab 8.1.3 Several of the solutions used in macroetching react
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saturated with solution and frequently sweep over the surface
of the specimen to renew the solution. When the structure has
vigorously with the metal and can overheat the specimen. In
these cases the specimen is periodically removed from the

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been suitably developed, rinse the specimen, either with a swab solution, cooled in running water, and re-immersed in the
saturated with water, or better still, by pouring water over the etchant. This procedure is repeated until the desired degree of
specimen. After rinsing with hot water, blow the specimen dry etching is obtained.
with compressed air. Details of the procedure not discussed 8.1.4 Macroetchants for Aluminum and Aluminum Alloys
ASTM
here are covered in the sections for the various metals E340-23
and their (Table 1).
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alloys.
8.2 Beryllium:
7.3 The times and temperatures given in individual tabula- 8.2.1 Beryllium and its compounds in the finely divided
tions are only intended as guides. In fact, the progress of state are extremely poisonous. Even in the massive form,
etching should be closely watched and etching stopped when beryllium can be hazardous. Warning—Before starting any
the preferred structural details have been revealed. Specimens work involving beryllium, a review of hazards and plans for
should be etched to develop structure. Generally, a light etch is handling should be made.
better than a heavy etch; overetching can often lead to 8.2.1.1 Generally speaking, beryllium and its alloys have
misinterpretation. The actual time to develop a structure given difficulty in obtaining good macroetched specimens.
properly may be quite different from the one suggested. First, beryllium is a rather brittle metal and sectioning can be
8. Specific Preparation Procedures and Recommended difficult. Secondly, beryllium does not grind easily; hence,
Solutions specimens should be as small as possible to minimize grinding
time. Grinding has been most successful with the entire
8.1 Aluminum: sequence of wet silicon carbide papers.
8.1.1 The specimens can be cut using common cutting tools,
8.2.1.2 The etching of fine grained metal may not always be
hack saws, band saws, shears, abrasive cutoff wheels, and so
entirely successful, and further preparation will be required.
forth. All these methods will cause cold work at the surface and
Rough polishing with 15 µm Al2O3 suspended in water is
will generate heat. The temperature rise can be enough to cause
performed on a low-nap cloth. Light pressure and frequent
changes in structure. For these reasons sharp tools and gener-
change of cutting direction produce the best results. If further
ous lubrication are necessary for sectioning.
polishing is required, 1-µm green Cr2O3 in water on synthetic
8.1.2 The cold-worked surface should be removed by ma-
suede works best.
chining the surface. Again sharp tools and copious lubrication
8.2.2 Macroetchants for Beryllium and Beryllium Alloys—
are required. If fine detail is required, the machined surface
(Table 2).
should be ground using silicon carbide paper lubricated with
water or kerosene. 8.3 Cobalt and Cobalt Alloys:

4
 E340 − 23
TABLE 5 Macroetchants for Iron and Steel
Alloys Composition Procedure Comments
Plain and alloy steels, HCl (concentrated) 50 mL Immerse specimen in solution heated to 160 °F to General purpose.
high-speed and tool steels, H2O 50 mL 180 °F for 15 min to 30 min. Desmut by vigorous
cutlery (12 %–14 % Cr) and scrubbing with vegetable fiber brush under
stainless steels running water. Stainless steels may be desmutted
by dipping in a warm 20 % HNO3 to give a bright
finish.

High-alloy steels HCl (concentrated) 50 mL Immerse specimen for 10 min to 15 min in Ratio HCl:HNO3 runs 2:1 to 3:1.
HNO3 (concentrated) 25 mL solution at room temperature. Rinse in warm
H2O 25 mL water and dry.

Plain and alloy steels, cutlery HCl (concentrated) 38 mL Immerse specimen for 15 min to 45 min in Works well on 12 % Cr steel.
steels H2SO4 (concentrated) 12 mL solution heated to 160 °F to 180 °F. Rinse in
H2O 50 mL warm water and dry.

High-alloy steels HNO3 (concentrated) 10 mL Immerse specimen in solution heated to 160 °F to Ratio HNO3-HF varies.
HF (48 %) 4 mL 180 °F until desired etch is obtained and rinse in
H2O 87 mL warm water and dry.
to
HNO3 (concentrated) 40 mL
HF (48 %) 10 mL
H2O 50 mL

Stainless steels, high-alloy HCl (concentrated) 50 mL Mix HCl and water then heat to 160 °F to 170 °F. Produces bright finish.
steels H2O 50 mL Immerse specimen and add H2O2 in several
H2O2 (30 %) 20 mL parts. Do not mix. Make each subsequent
addition after foaming from previous addition has
stopped.

Austenitic stainless steels HCl (concentrated) 50 mL Immerse specimen in solution which may be Marble’s reagent. Light etch, good for
saturated solution heated or not depending upon alloy. Time also structure.

Plain and low-alloy steels

iTeh Standards
of CuSO4 in H2O

(NH4)2S2O8 (ammo-
25 mL

10 g
depends on alloy. Rinse in warm water and dry.

Swab solution at room temperature over Grain size, weldments.

H2O(https://standards.iteh.ai)
nium persulfate)
100 mL
specimen. Rinse and dry.

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Plain and alloy steels CuCl2 2.5 g Immerse in solution at room temperature until a Stead’s reagent. Salts dissolved in HCl
MgCl2 10 g coppery sheen appears. Rinse thoroughly and with minimum of hot water. To bring out
HCl (concentrated) 5 mL dry. P-rich areas and P banding.
Alcohol—up to 250 mL

Mild steel, Bessemer and high CuCl2 ASTM The E340-23 90 g

surface should be rubbed with cloth soaked Fry’s reagent. Before etching, sample
N2 steel HCl (concentrated) 120 mL
in etching solution. Wash in alcohol or rinse in should be heated to 200 °C to 250 °C
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H2 O 100 mL
HCl (1 + 1) after etching to prevent deposition of (302 °F to 482 °F) for 5 min to 30 min
copper. depending on condition of steel. To
show strain lines due to cold work.

Plain and alloy steels CuCl2 45 g As above. Modified Fry’s reagent. Same as Fry’s
HCl (concentrated) 180 mL Reagent but modified by Wazau, may
H2 O 100 mL give more contrast. Specimen can be
washed in water without depositing
copper.

Stainless and high-Cr steels HCl 10 mL Immerse specimen in solution at room Vilella’s reagent.
Alcohol 100 mL temperature until desired contrast is obtained.
Picric acid 1g Rinse and dry.

Plain and alloy steels HCl (concentrated) 6 to 12 mL Electrolytic, 5 to 10 A per square inch, specimen Small specimens, <20 in.2 area.
H2O 100 mL vertical, rinse, brush, and dry.

Plain and alloy steels HCl (concentrated) 6 mL Electrolytic, specimen moves past a cathode bar, For specimens over 20 in.2 area,
H2 O 100 mL 30 to 40 A per inch of specimen width, rinse, blooms, billets, and slabs.
HBO3 1g brush, and dry.

Plain and alloy steels H2O 50 mL Immerse in solution at room temperature until “3-2-1 etch.” Specimens can be
HCl (concentrated) 33 mL reaction stops. Rinse in warm water, brush, dry completely immersed. Refresh for
H2O2 (30 %) 17 mL immediately. reuse with small additions of 30 %
H2O2

5
 E340 − 23
TABLE 6 Macroetchants for Stainless Steels and High-Temperature Alloys
Alloys Composition Procedure Comments
Stainless steels and iron- HCl (concentrated) 50 mL Immerse specimen in solution heated to General purpose.
base H2O 50 mL 160 °F to 180 °F for 30 min. Desmut by
high-temperature alloys vigorous scrubbing with vegetable brush
under running water. Stainless steels may
be desmutted by dipping in warm 20 %
HNO3 to give bright finish. Dropwise or
slow addition of H2O is often effective in
accelerating etching.

Iron-, cobalt-, and nickel- HCl (concentrated) 50 mL Immerse specimen in solution at room Ratio HCl + HNO3 runs 2 + 1 to
base HNO3 (concentrated) 25 mL temperature for 10 min to 30 min. Rinse 3+1
high-temperature alloys H2O 25 mL and dry.

Stainless steels and high- HNO3 10 mL Immerse specimen in solution heated to Ratio HNO3-HF varies.
temperature alloys HF (48 %) 3 mL 160 °F to 180°F until desired contrast is
H2O 87 mL obtained. Rinse and dry.
to
HNO3 (concentrated) 40 mL
HF (48 %) 10 mL
H2O 50 mL

Austenitic stainless steels I (NH4)2 SO4 15 g Combine I and II then add III. Immerse Lepito’s etch. I, mix fresh, grain
and H2O 75 mL specimen in solution at room temperature structure.
nickel base alloys II FeCl3 250 g until desired contrast is obtained.
HCl 100 mL
(concentrated) 30 mL
III HNO3
(concentrated)

Austenitic stainless steels HCl (concentrated) 50 mL Mix HCl and water then heat, immerse
and H2O 50 mL specimen and add H2 O2 in several parts.
high-temperature alloys
iTeh Standards
H2O2 (30 %) 20 mL Do not mix. Make each subsequent
addition after foaming from previous
addition has stopped.

Austenitic stainless steels

and
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HCl (concentrated)
Sat soln of
50 mL
25 mL
Immerse specimens in solution which may
be heated up to 170 °F until desired
Marble’s reagent. Light etch, good
for structures. Amount of CuSO4

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high-temperature alloys CuSO4 in H2O contrast is obtained. Rinse and dry. solution may be increased to 1 + 1
ratio for difficult alloys.

TABLE 7 Macroetchants for Lead and Lead Alloys

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Alloy Composition Procedure Comments
Lead and lead A. H2O 250 mL Add A to B and let precipitate redissolve. If B is added to A an
alloys NH4OH (sp gr 0.90) 140 mL insoluble precipitate forms.
HNO3 (concentrated) 60 mL Add C to mixture of A and B after precipitate has redissolved.
Molybdic acid (85 %) 100 mL
B. H2O 960 mL Swab surface of the specimen with mixed solution until desired
HNO3 (concentrated) 400 mL contrast is obtained. Rinse and dry.
C. Glacial acetic acid 100 mL

Antimonial lead A. Glacial acetic acid 30 mL Prepare surface on silk velvet wheel with Al2 O3 abrasive at 150
HNO3 (concentrated) 40 mL rpm. Etch with solution A at 42 °C then repolish until bright.
H2O 16 mL Reetch with B at room temperature for 1 to 2 h.
B. Glacial acetic acid 1 mL
H2O 400 mL

A. HNO3 (concentrated) 80 mL Mix equal quantities of A and B immediately before use. Immerse Grain structure
H2 O 220 mL specimen in solution at room temperature until desired contrast is
B. (NH4)2 MoO4 45 g obtained. Rinse and dry.
H2O

A. (NH4)2 MoO4 10 g Immerse specimen in solution at room temperature until desired Bright etch, grain
Citric acid 25 g contrast is obtained, then rinse and dry. structure, defects.
H2O 100 mL

A. Acetic acid 75 mL Mix with strongest H2O2 available to minimize water content. Chemical polish-etch.
H2O2 25 mL Immerse dry specimen in solution at room temperature until
desired contrast is obtained, then rinse and dry.