ASTM E1180-08(2021)
(Practice)Standard Practice for Preparing Sulfur Prints for Macrostructural Evaluation
Standard Practice for Preparing Sulfur Prints for Macrostructural Evaluation
SIGNIFICANCE AND USE
5.1 The sulfur print reveals the distribution of sulfur as sulfide inclusions in the specimen. The sulfur print complements macroetch methods by providing an additional procedure for evaluating the homogeneity of a steel product.
5.2 Sulfur prints of as-cast specimens generally reveal the solidification pattern and may be used to assess the nature of deoxidation, that is, rimming action versus killed steel sulfur distributions.
5.3 Sulfur prints will reveal segregation patterns, including refilled cracks, and may reveal certain physical irregularities, for example, porosity or cracking.
5.4 The nature of metal flow, such as in various forging operations, can be revealed using sulfur prints of specimens cut parallel to the metal flow direction.
5.5 The sulfur print method is suitable for process control, research and development studies, failure analysis, and for material acceptance purposes.
5.6 The intensity of the sulfur print is influenced by the concentration of sulfur in the steel, the chemical composition of the sulfide inclusions, the aggressiveness of the aqueous acid solution, and the duration of the contact printing between the acid soaked emulsion coated paper and the ground surface of the specimen (this time is the order of seconds rather than minutes). Very low sulfur content steels will produce too faint an image to be useful for macrostructural evaluations. Selection of appropriate printing practices including selection of type of emulsion coated media, acid type and strength, will yield satisfactory prints. Very faint images in the sulfur print can be made more visible by scanning the sulfur print into a PC, and using a photo editor to increase the color saturation. Steels with compositions that produce predominantly titanium or chromium sulfides will not produce useful images.
SCOPE
1.1 This practice provides information required to prepare sulfur prints (also referred to as Baumann Prints) of most ferrous alloys to reveal the distribution of sulfide inclusions.
1.2 The sulfur print reveals the distribution of sulfides in steels with bulk sulfur contents between about 0.010 and 0.40 weight percent.
1.3 Certain steels contain complex sulfides that do not respond to the test solutions, for example, steels containing titanium sulfides or chromium sulfides.
1.4 The sulfur print test is a qualitative test. The density of the print image should not be used to assess the sulfur content of a steel. Under carefully controlled conditions, it is possible to compare print image intensities if the images are formed only by manganese sulfides.
1.5 The sulfur print image will reveal details of the solidification pattern or metal flow from hot or cold working on appropriately chosen and prepared test specimens.
1.6 This practice does not address acceptance criteria based on the use of the method.
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.8 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 limitations prior to use. For specific precautionary statements, see Section 9.
1.9 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.
General Information
Relations
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: E1180 − 08 (Reapproved 2021)
Standard Practice for
Preparing Sulfur Prints for Macrostructural Evaluation
This standard is issued under the fixed designation E1180; 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.
1. Scope 2. Referenced Documents
1.1 This practice provides information required to prepare 2.1 ASTM Standards:
sulfur prints (also referred to as Baumann Prints) of most
E3 Guide for Preparation of Metallographic Specimens
ferrous alloys to reveal the distribution of sulfide inclusions.
E7 Terminology Relating to Metallography
E340 Practice for Macroetching Metals and Alloys
1.2 The sulfur print reveals the distribution of sulfides in
E381 Method of Macroetch Testing Steel Bars, Billets,
steels with bulk sulfur contents between about 0.010 and 0.40
Blooms, and Forgings
weight percent.
E407 Practice for Microetching Metals and Alloys
1.3 Certain steels contain complex sulfides that do not
respond to the test solutions, for example, steels containing
3. Terminology
titanium sulfides or chromium sulfides.
3.1 Definitions—For definitions of terms used in this
1.4 The sulfur print test is a qualitative test. The density of
practice, see Terminology E7.
the print image should not be used to assess the sulfur content
of a steel. Under carefully controlled conditions, it is possible
4. Summary of Practice
to compare print image intensities if the images are formed
4.1 The sulfur print provides a means for macroscopic
only by manganese sulfides.
evaluation of the sulfur distribution in steels and cast irons by
1.5 The sulfur print image will reveal details of the solidi-
contact printing using photographic paper soaked in an aque-
fication pattern or metal flow from hot or cold working on
ous acid solution, for example, sulfuric acid, citric acid, or
appropriately chosen and prepared test specimens.
acetic acid.
1.6 This practice does not address acceptance criteria based
4.2 The test specimen is usually a disk or rectangular
on the use of the method.
section, such as used in macroetch evaluations, cut from an
1.7 The values stated in SI units are to be regarded as
as-cast or wrought specimen with either a transverse or
standard. No other units of measurement are included in this
longitudinal orientation. The specimen is freshly ground
standard.
smooth and cleaned to remove cutting oils, scale, abrasives, or
1.8 This standard does not purport to address all of the
other contaminants. The specimen should be at room tempera-
safety concerns, if any, associated with its use. It is the
ture when sulfur printed.
responsibility of the user of this standard to establish appro-
4.3 A sheet of photographic paper with (usually) a matte
priate safety, health, and environmental practices and deter-
surface finish of appropriate size is soaked in the dilute
mine the applicability of regulatory limitations prior to use.
aqueous acid solution, any excess liquid removed, and the
For specific precautionary statements, see Section 9.
emulsion side of the paper is placed on the ground surface of
1.9 This international standard was developed in accor-
the specimen. After a suitable time, the paper is removed,
dance with internationally recognized principles on standard-
washed in water, fixed, washed again in water, and dried as flat
ization established in the Decision on Principles for the
as possible.
Development of International Standards, Guides and Recom-
4.4 The distribution of sulfur in the specimen is revealed as
mendations issued by the World Trade Organization Technical
a mirror image on the photographic paper as darkly colored
Barriers to Trade (TBT) Committee.
areas of silver sulfide embedded in the emulsion.
This practice is under the jurisdiction of ASTM Committee E04 on Metallog-
raphy and is the direct responsibility of Subcommittee E04.01 on Specimen
Preparation. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Sept. 1, 2021. Published September 2021. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1987. Last previous edition approved in 2014 as E1180 – 08(2014). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/E1180-08R21. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1180 − 08 (2021)
5. Significance and Use If the pre-etchant contains sulfate ions (for example, a stainless
steel specimen etched with Marble’s reagent), the print will be
5.1 The sulfur print reveals the distribution of sulfur as
lightly colored, even if sulfides are not present in the steel.
sulfide inclusions in the specimen. The sulfur print comple-
Such etchants should not be used for this purpose.
ments macroetch methods by providing an additional proce-
dure for evaluating the homogeneity of a steel product. 6.6 If chromium replaces some of the manganese in the
sulfide inclusions, the print intensity for a given sulfur level
5.2 Sulfur prints of as-cast specimens generally reveal the
will be reduced.An image will not be obtained, irrespective of
solidification pattern and may be used to assess the nature of
thesulfurcontent,iftitaniumorchromiumsulfidesarepresent.
deoxidation, that is, rimming action versus killed steel sulfur
distributions.
7. Apparatus
5.3 Sulfur prints will reveal segregation patterns, including
7.1 Lighting—If the chosen photographic paper when ex-
refilled cracks, and may reveal certain physical irregularities,
posed to the existing room light for 15 min changes from white
for example, porosity or cracking.
to light blue and then clears back to white when processed in
5.4 The nature of metal flow, such as in various forging
the sequence of solutions, there is no need to turn off the
operations,canberevealedusingsulfurprintsofspecimenscut
existing white lighting, and work under amber bulb lighting;
parallel to the metal flow direction.
never expose the paper to sunlight.
5.5 The sulfur print method is suitable for process control,
7.2 Shallow Container, such as a photographic tray, is
research and development studies, failure analysis, and for
required to contain the dilute aqueous acid solution. The
material acceptance purposes.
container must be large enough to soak the emulsion coated
5.6 The intensity of the sulfur print is influenced by the paper without wrinkling.
concentration of sulfur in the steel, the chemical composition
7.3 Timing Device, such as used in a photographic
ofthesulfideinclusions,theaggressivenessoftheaqueousacid
darkroom, is helpful for timing the contact printing time, and
solution, and the duration of the contact printing between the
the washing and fixing periods.
acid soaked emulsion coated paper and the ground surface of
7.4 Tank, of suitable size with cool flowing water, is
the specimen (this time is the order of seconds rather than
required for washing the print.
minutes). Very low sulfur content steels will produce too faint
an image to be useful for macrostructural evaluations. Selec- 7.5 Tank, or Covered Tray, to hold the fixing agent and the
tion of appropriate printing practices including selection of print; two can be used sequentially for faster fixing when using
type of emulsion coated media, acid type and strength, will emulsion coated double weight fiber based paper.
yield satisfactory prints. Very faint images in the sulfur print
7.6 Drying—Heated drum dryers are no longer made.
can be made more visible by scanning the sulfur print into a
Heated drying cabinets are available for fiber base prints laid
PC, and using a photo editor to increase the color saturation.
horizontally on a screen. Resin coated papers can be dried with
Steels with compositions that produce predominantly titanium
an infra red dryer very quickly. Clothes lines and cork peg
or chromium sulfides will not produce useful images.
boards will also work but the prints do not dry perfectly flat.
6. Interferences
8. Reagents and Materials
6.1 The specimen must be properly cleaned, otherwise dark
8.1 Photographic paper is a multilayer paper coated with a
spots will be produced which may be incorrectly interpreted as
gelatin emulsion containing about 80 mg per square meter of
a gross sulfide segregate.
silver as a halide (Cl and/or Br) supported by a paper base that
6.2 Hydrogen sulfide gas is produced while the paper is in
is nominally single or double weight (110 g/sq. m or 235 g/sq.
contact with the specimen. The hydrogen sulfide is readily m).Thespeedandcontrastcharacteristicsareofnoimportance
absorbed by the wet emulsion. The hydrogen sulfide reacts
when sulfur printing.The paper base may be fibre base or resin
with the silver halides in the emulsion to lay down insoluble coated. A thin layer of baryta may separate the emulsion and
silver sulfide. If the specimen contains pores or cracks,
the base in order to provide a more visible image. A glossy
hydrogen sulfide gas may become entrapped in these openings emulsion is preferred to a matte emulsion if image sharpness is
and may produce a brown color on the paper which may be
important; the problem is that a glossy emulsion may slide on
incorrectly interpreted as a gross sulfide segregate. the steel surface and cause blurring.Afibre base is preferred to
a resin coated base because the fibre base tends to better
6.3 If air is entrapped between the contacting paper and
conform to the steel surface; in addition it has less tendency to
specimen, and is not removed, a white spot may be produced
slip when smoothing the paper over the steel surface. Note that
on the print. Air entrapment must be quickly removed by the
photo paper for digital photo printing contains no silver halide
use of a rubber squeegee or roller to move bubbles to the edge
emulsion and is not suitable for sulfur printing. The advantage
of the specimen.
of resin coated photographic paper, over fibre base paper, is
6.4 Image blurring may result from movement of the paper
that the paper base is sealed from contact with the dilute acid,
during contact.
the rapid fixer, and the water during washing; hence the
6.5 Specimens with low sulfur contents are often pre-etched processingtime,includingdryingtime,ismuchless,especially
before printing to expose more sulfides and enhance the image. if double weight paper is used. Photographic paper is available
E1180 − 08 (2021)
in cut sheets and rolls of various widths. Cut sheets are ideal if 10.2 The number, orientation, and location of specimens
the specimen size matches the sheet size. Roll dispensed paper may be subject to producer-purchaser agreement.
can be fed from a “safe” box and cut as needed. The paper
10.3 Specimens should be cut in a region away from any
sheet should be 12 mm to 20 mm larger than the specimen
effects from hot shearing or burning; unlike macroetching, the
around the perimeter of the specimen. If the overhang of the
sulfur print appearance is not affected by being within the heat
paper is too great then the paper will not lie tight to the edge
affected zone (HAZ) which results from the torch cutting of
of the specimen.
cold steel.
8.2 Technical or reagent grade acids, sulfuric acid, acetic
10.4 Specimens can be thin enough for ease of handling,
acid,citricacid,etc.,areusedtomakethesolutioninwhichthe
generally 12 mm to 25 mm thick, but may be thicker,
paper is soaked prior to contact printing; typical concentrations
especially if being prepared on only one side for electrolytical
of acidare2 %to10 %sulfuricacid,10 %to15 %acetic acid,
macroetching after sulfur printing (40 mm to 50 mm thick).
and 10 % to 15 % citric acid.
Thesurfacetobecontactprintedshouldbefreshlygrounduntil
8.3 A commercial photographic fixing solution (rapid fixer
smooth, and carefully cleaned. Edges should be free of flash,
contains ammonium thiosulfate rather than sodium thiosulfate)
burrs, or scale.
is used to fix the sulfur print image after contact printing and
10.5 Very smooth surfaces, such as produced by polishing,
washing. The fixer should be tested periodically to ensure that
will promote slippage between the paper and disk resulting in
it is still active; set aside a print in the sunlight and if the
blurred images. A 250 micron (60 grit as packaged) finish
appearance changes then the fixer is depleted and should be
provided by dry grinding with a hand held abrasive grit disc
replaced. Used fixer contains silver and should be disposed of
sander, or a contact wheel belt sander is satisfactory. Using a
in concordance with local regulations. There is not enough
face mill may leave tool marks that show up in the sulfur print.
silver to justify having the silver recovered from the used fixer.
Using a (single) wiper insert for the final pass may leave the
surface so smooth that it must be sanded to make it rough
9. Hazards
enough for sulfur printing.Avitreous bonded abrasive surface
9.1 Sulfuric acid, H SO , is a highly corrosive, dangerously
2 4
grinder may be used as long as the final pass is very light and
reactive, strong oxidizing agent. It reacts with water releasing
removes only 5 micrometer. The surface should be cleaned
substantial heat. Add sulfuric acid very slowly to the water
with methanol to remove oils and other soils. The final surface
with constant stirring. Contact with concentrated sulfuric acid
roughness Ra should be no less than 0.4 micrometer and may
must be avoided. The dilute solution used to soak the prints is
be as large as 1.6 micrometer if the paper tends to slip too
not particularly dangerous but exposure to it should be mini-
easily on a smoother surface.
mized and hands should be washed after any contact. The use
10.6 Surface preparation (see Methods E3, E340 and E381)
of rubber gloves should be considered. Use tongs to handle the
should not produce excessive cold work at the test surface that
paper in the soaking solution. The other acids recommended
can close up voids and cracks.
for sensitizing the paper are less aggressive than sulfuric acid,
however, appropriate care should be taken in mixing and
11. Procedure
handling.
9.2 The reactions during sulfur printing are as follows:
11.1 Soak the photographic paper in the selected aqueous
acidsolution.Thestrengthofthesolutionwilldependuponthe
H SO 1MnS 5 H S1MnSO (1)
2 4 2 4
acid selected, the sulfur content of the steel
...
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