ASTM E1180-08(2014)

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 and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see Section 9.

General Information

• Status: Historical
• Publication Date: 30-Sep-2014
• ICS: 71.060.10 - Chemical elements
• Technical Committee: E04 - Metallography
• Drafting Committee: E04.01 - Specimen Preparation

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: E1180 − 08 (Reapproved 2014)
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 E7 Terminology Relating to Metallography
E340 Test Method for Macroetching Metals and Alloys
1.1 This practice provides information required to prepare
E381 Method of Macroetch Testing Steel Bars, Billets,
sulfur prints (also referred to as Baumann Prints) of most
Blooms, and Forgings
ferrous alloys to reveal the distribution of sulfide inclusions.
E407 Practice for Microetching Metals and Alloys
1.2 The sulfur print reveals the distribution of sulfides in
steels with bulk sulfur contents between about 0.010 and 0.40 3. Terminology
weight percent.
3.1 Definitions—For definitions of terms used in this
1.3 Certain steels contain complex sulfides that do not
practice, see Terminology E7.
respond to the test solutions, for example, steels containing
4. Summary of Practice
titanium sulfides or chromium sulfides.
4.1 The sulfur print provides a means for macroscopic
1.4 The sulfur print test is a qualitative test. The density of
evaluation of the sulfur distribution in steels and cast irons by
the print image should not be used to assess the sulfur content
contact printing using photographic paper soaked in an aque-
of a steel. Under carefully controlled conditions, it is possible
ous acid solution, for example, sulfuric acid, citric acid, or
to compare print image intensities if the images are formed
acetic acid.
only by manganese sulfides.
4.2 The test specimen is usually a disk or rectangular
1.5 The sulfur print image will reveal details of the solidi-
section, such as used in macroetch evaluations, cut from an
fication pattern or metal flow from hot or cold working on
as-cast or wrought specimen with either a transverse or
appropriately chosen and prepared test specimens.
longitudinal orientation. The specimen is freshly ground
1.6 This practice does not address acceptance criteria based
smooth and cleaned to remove cutting oils, scale, abrasives, or
on the use of the method.
other contaminants. The specimen should be at room tempera-
1.7 The values stated in SI units are to be regarded as
ture when sulfur printed.
standard. No other units of measurement are included in this
4.3 A sheet of photographic paper with (usually) a matte
standard.
surface finish of appropriate size is soaked in the dilute
1.8 This standard does not purport to address all of the
aqueous acid solution, any excess liquid removed, and the
safety concerns, if any, associated with its use. It is the
emulsion side of the paper is placed on the ground surface of
responsibility of the user of this standard to establish appro-
the specimen. After a suitable time, the paper is removed,
priate safety and health practices and determine the applica-
washed in water, fixed, washed again in water, and dried as flat
bility of regulatory limitations prior to use. For specific
as possible.
precautionary statements, see Section 9.
4.4 The distribution of sulfur in the specimen is revealed as
2. Referenced Documents a mirror image on the photographic paper as darkly colored
areas of silver sulfide embedded in the emulsion.
2.1 ASTM Standards:
E3 Guide for Preparation of Metallographic Specimens
5. Significance and Use
5.1 The sulfur print reveals the distribution of sulfur as
This practice is under the jurisdiction of ASTM Committee E04 on Metallog-
sulfide inclusions in the specimen. The sulfur print comple-
raphy and is the direct responsibility of Subcommittee E04.01 on Specimen
Preparation.
ments macroetch methods by providing an additional proce-
Current edition approved Oct. 1, 2014. Published December 2014. Originally
dure for evaluating the homogeneity of a steel product.
approved in 1987. Last previous edition approved in 2008 as E1180 – 08. DOI:
10.1520/E1180-08R14.
5.2 Sulfur prints of as-cast specimens generally reveal the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
solidification pattern and may be used to assess the nature of
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
deoxidation, that is, rimming action versus killed steel sulfur
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. distributions.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1180 − 08 (2014)
5.3 Sulfur prints will reveal segregation patterns, including 7. Apparatus
refilled cracks, and may reveal certain physical irregularities,
7.1 Lighting—If the chosen photographic paper when ex-
for example, porosity or cracking.
posed to the existing room light for 15 min changes from white
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
is nominally single or double weight (110 or 235 g/sq. m). The
6.2 Hydrogen sulfide gas is produced while the paper is in
speed and contrast characteristics are of no importance when
contact with the specimen. The hydrogen sulfide is readily
sulfur printing. The paper base may be fibre base or resin
absorbed by the wet emulsion. The hydrogen sulfide reacts
coated. A thin layer of baryta may separate the emulsion and
with the silver halides in the emulsion to lay down insoluble
the base in order to provide a more visible image. A glossy
silver sulfide. If the specimen contains pores or cracks,
emulsion is preferred to a matte emulsion if image sharpness is
hydrogen sulfide gas may become entrapped in these openings
important; the problem is that a glossy emulsion may slide on
and may produce a brown color on the paper which may be
the steel surface and cause blurring.Afibre base is preferred to
incorrectly interpreted as a gross sulfide segregate.
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
that the paper base is sealed from contact with the dilute acid,
6.4 Image blurring may result from movement of the paper
the rapid fixer, and the water during washing; hence the
during contact.
processingtime,includingdryingtime,ismuchless,especially
6.5 Specimens with low sulfur contents are often pre-etched
if double weight paper is used. Photographic paper is available
before printing to expose more sulfides and enhance the image.
in cut sheets and rolls of various widths. Cut sheets are ideal if
If the pre-etchant contains sulfate ions (for example, a stainless
the specimen size matches the sheet size. Roll dispensed paper
steel specimen etched with Marble’s reagent), the print will be
can be fed from a “safe” box and cut as needed. The paper
lightly colored, even if sulfides are not present in the steel.
sheet should be 12 to 20 mm larger than the specimen around
Such etchants should not be used for this purpose.
the perimeter of the specimen. If the overhang of the paper is
too great then the paper will not lie tight to the edge of the
6.6 If chromium replaces some of the manganese in the
specimen.
sulfide inclusions, the print intensity for a given sulfur level
will be reduced.An image will not be obtained, irrespective of 8.2 Technical or reagent grade acids, sulfuric acid, acetic
thesulfurcontent,iftitaniumorchromiumsulfidesarepresent. acid,citricacid,etc.,areusedtomakethesolutioninwhichthe
E1180 − 08 (2014)
paper is soaked prior to contact printing; typical concentrations beingpreparedononlyonesideforelectrolyticalmacroetching
of acid are 2 to 10 % sulfuric acid, 10 to 15 % acetic acid, and after sulfur printing (40 to 50 mm thick). The surface to be
10 to 15 % citric acid. contact printed should be freshly ground until smooth, and
carefullycleaned.Edgesshouldbefreeofflash,burrs,orscale.
8.3 A commercial photographic fixing solution (rapid fixer
contains ammonium thiosulfate rather than sodium thiosulfate) 10.5 Very smooth surfaces, such as produced by polishing,
is used to fix the sulfur print image after contact printing and will promote slippage between the paper and disk resulting in
washing. The fixer should be tested periodically to ensure that blurred images. A 250 micron (60 grit as packaged) finish
it is still active; set aside a print in the sunlight and if the provided by dry grinding with a hand held abrasive grit disc
appearance changes then the fixer is depleted and should be sander, or a contact wheel belt sander is satisfactory. Using a
replaced. Used fixer contains silver and should be disposed of face mill may leave tool marks that show up in the sulfur print.
in concordance with local regulations. There is not enough Using a (single) wiper insert for the final pass may leave the
silver to justify having the silver recovered from the used fixer. surface so smooth that it must be sanded to make it rough
enough for sulfur printing.Avitreous bonded abrasive surface
9. Hazards
grinder may be used as long as the final pass is very light and
removes only 5 micrometer. The surface should be cleaned
9.1 Sulfuric acid, H SO , is a highly corrosive, dangerously
2 4
with methanol to remove oils and other soils. The final surface
reactive, strong oxidizing agent. It reacts with water releasing
roughness Ra should be no less than 0.4 micrometer and may
substantial heat. Add sulfuric acid very slowly to the water
be as large as 1.6 micrometer if the paper tends to slip too
with constant stirring. Contact with concentrated sulfuric acid
easily on a smoother surface.
must be avoided. The dilute solution used to soak the prints is
not particularly dangerous but exposure to it should be mini-
10.6 Surface preparation (see Methods E3, E340 and E381)
mized and hands should be washed after any contact. The use
should not produce excessive cold work at the test surface that
of rubber gloves should be considered. Use tongs to handle the
can close up voids and cracks.
paper in the soaking solution. The other acids recommended
11. Procedure
for sensitizing the paper are less aggressive than sulfuric acid,
however, appropriate care should be taken in mixing and
11.1 Soak the photographic paper in the selected aqueous
handling.
acidsolution.Thestrengthofthesolutionwilldependuponthe
acid selected, the sulfur content of the steel and the desired
9.2 The reactions during sulfur printing are as follows:
printing time (the reaction is very rapid). AISI 10XX steels
H SO 1MnS 5 H S1MnSO (1)
2 4 2 4
with sulfur contents between 0.015 wt % and 0.035 wt % are
H SO 1FeS 5 H S1FeSO (2)
2 4 2 4 typically printed using a 2 % sulfuric acid solution.AISI 11XX
series steels are more successfully printed with a 15 % citric
~there may be some ferrous sulfide in the steel!
acid solution. Steels with low sulfur contents (under 0.010
H S12Ag Cl 5 Ag S12HClor (3)
2 2 wt %) may be printed using 5 to 10 % sulfuric acid solutions.
When large size prints are desired, a longer working time may
H S12AgBr 5 Ag Br12HCl or both.
2 2
Warning—Note that hydrogen sulfide is released into the be required, necessitating a weaker acid solution.
room. Hydrogen sulfide is toxic and needs to be exhausted
11.2 Soak the paper in the solution for 1 to 5 min. A 3-min
from the room if more than a few samples are sulfur printed
soak time is commonly used. Periods in excess of 5 min may
per 8 hour time period. If you can smell the hydrogen sul
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1180 − 08 E1180 − 08 (Reapproved 2014)
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
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 and health practices and determine the applicability of regulatory
limitations prior to use. For specific precautionary statements, see Section 9.
2. Referenced Documents
2.1 ASTM Standards:
E3 Guide for Preparation of Metallographic Specimens
E7 Terminology Relating to Metallography
E340 Test Method for Macroetching Metals and Alloys
E381 Method of Macroetch Testing Steel Bars, Billets, Blooms, and Forgings
E407 Practice for Microetching Metals and Alloys
3. Terminology
3.1 Definitions—For definitions of terms used in this practice, see Terminology E7.
4. Summary of Practice
4.1 The sulfur print provides a means for macroscopic evaluation of the sulfur distribution in steels and cast irons by contact
printing using photographic paper soaked in an aqueous acid solution, for example, sulfuric acid, citric acid, or acetic acid.
4.2 The test specimen is usually a disk or rectangular section, such as used in macroetch evaluations, cut from an as-cast or
wrought specimen with either a transverse or longitudinal orientation. The specimen is freshly ground smooth and cleaned to
remove cutting oils, scale, abrasives, or other contaminants. The specimen should be at room temperature when sulfur printed.
This practice is under the jurisdiction of ASTM Committee E04 on Metallography and is the direct responsibility of Subcommittee E04.01 on Specimen Preparation.
Current edition approved Oct. 1, 2008Oct. 1, 2014. Published October 2008 December 2014. Originally approved in 1987. Last previous edition approved in 20032008
ε1
as E1180 – 03E1180 – 08. . DOI: 10.1520/E1180-08.10.1520/E1180-08R14.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1180 − 08 (2014)
4.3 A sheet of photographic paper with (usually) a matte surface finish of appropriate size is soaked in the dilute aqueous acid
solution, any excess liquid removed, and the emulsion side of the paper is placed on the ground surface of the specimen. After a
suitable time, the paper is removed, washed in water, fixed, washed again in water, and dried as flat as possible.
4.4 The distribution of sulfur in the specimen is revealed as a mirror image on the photographic paper as darkly colored areas
of silver sulfide embedded in the emulsion.
5. 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.
6. Interferences
6.1 The specimen must be properly cleaned, otherwise dark spots will be produced which may be incorrectly interpreted as a
gross sulfide segregate.
6.2 Hydrogen sulfide gas is produced while the paper is in contact with the specimen. The hydrogen sulfide is readily absorbed
by the wet emulsion. The hydrogen sulfide reacts with the silver halides in the emulsion to lay down insoluble silver sulfide. If
the specimen contains pores or cracks, hydrogen sulfide gas may become entrapped in these openings and may produce a brown
color on the paper which may be incorrectly interpreted as a gross sulfide segregate.
6.3 If air is entrapped between the contacting paper and specimen, and is not removed, a white spot may be produced on the
print. Air entrapment must be quickly removed by the use of a rubber squeegee or roller to move bubbles to the edge of the
specimen.
6.4 Image blurring may result from movement of the paper during contact.
6.5 Specimens with low sulfur contents are often pre-etched before printing to expose more sulfides and enhance the image. If
the pre-etchant contains sulfate ions (for example, a stainless steel specimen etched with Marble’s reagent), the print will be lightly
colored, even if sulfides are not present in the steel. Such etchants should not be used for this purpose.
6.6 If chromium replaces some of the manganese in the sulfide inclusions, the print intensity for a given sulfur level will be
reduced. An image will not be obtained, irrespective of the sulfur content, if titanium or chromium sulfides are present.
7. Apparatus
7.1 Lighting—If the chosen photographic paper when exposed to the existing room light for 15 min changes from white to light
blue and then clears back to white when processed in the sequence of solutions, there is no need to turn off the existing white
lighting, and work under amber bulb lighting; never expose the paper to sunlight.
7.2 Shallow Container, such as a photographic tray, is required to contain the dilute aqueous acid solution. The container must
be large enough to soak the emulsion coated paper without wrinkling.
7.3 Timing Device, such as used in a photographic darkroom, is helpful for timing the contact printing time, and the washing
and fixing periods.
7.4 Tank, of suitable size with cool flowing water, is required for washing the print.
7.5 Tank, or Covered Tray, to hold the fixing agent and the print; two can be used sequentially for faster fixing when using
emulsion coated double weight fiber based paper.
E1180 − 08 (2014)
7.6 Drying—Heated drum dryers are no longer made. Heated drying cabinets are available for fiber base prints laid horizontally
on a screen. Resin coated papers can be dried with an infra red dryer very quickly. Clothes lines and cork peg boards will also work
but the prints do not dry perfectly flat.
8. Reagents and Materials
8.1 Photographic paper is a multilayer paper coated with a gelatin emulsion containing about 80 mg per square meter of silver
as a halide (Cl and/or Br) supported by a paper base that is nominally single or double weight (110 or 235 g/sq. m). The speed
and contrast characteristics are of no importance when sulfur printing. The paper base may be fibre base or resin coated. A thin
layer of baryta may separate the emulsion and the base in order to provide a more visible image. A glossy emulsion is preferred
to a matte emulsion if image sharpness is important; the problem is that a glossy emulsion may slide on the steel surface and cause
blurring. A fibre base is preferred to a resin coated base because the fibre base tends to better conform to the steel surface; in
addition it has less tendency to slip when smoothing the paper over the steel surface. Note that photo paper for digital photo
printing contains no silver halide emulsion and is not suitable for sulfur printing. The advantage of resin coated photographic paper,
over fibre base paper, is that the paper base is sealed from contact with the dilute acid, the rapid fixer, and the water during washing;
hence the processing time, including drying time, is much less, especially if double weight paper is used. Photographic paper is
available in cut sheets and rolls of various widths. Cut sheets are ideal if the specimen size matches the sheet size. Roll dispensed
paper can be fed from a “safe” box and cut as needed. The paper sheet should be 12 to 20 mm larger than the specimen around
the perimeter of the specimen. If the overhang of the paper is too great then the paper will not lie tight to the edge of the specimen.
8.2 Technical or reagent grade acids, sulfuric acid, acetic acid, citric acid, etc., are used to make the solution in which the paper
is soaked prior to contact printing; typical concentrations of acid are 2 to 10 % sulfuric acid, 10 to 15 % acetic acid, and 10 to 15 %
citric acid.
8.3 A commercial photographic fixing solution (rapid fixer contains ammonium thiosulfate rather than sodium thiosulfate) is
used to fix the sulfur print image after contact printing and washing. The fixer should be tested periodically to ensure that it is still
active; set aside a print in the sunlight and if the appearance changes then the fixer is depleted and should be replaced. Used fixer
contains silver and should be disposed of in concordance with local regulations. There is not enough silver to justify having the
silver recovered from the used fixer.
9. Hazards
9.1 Sulfuric acid, H SO , is a highly corrosive, dangerously reactive, strong oxidizing agent. It reacts with water releasing
2 4
substantial heat. Add sulfuric acid very slowly to the water with constant stirring. Contact with concentrated sulfuric acid must be
avoided. The dilute solution used to soak the prints is not particularly dangerous but exposure to it should be minimized and hands
should be washed after any contact. The use of rubber gloves should be considered. Use tongs to handle the paper in the soaking
solution. The other acids recommended for sensitizing the paper are less aggressive than sulfuric acid, however, appropriate care
should be taken in mixing and handling.
9.2 The reactions during sulfur printing are as follows:
H SO 1MnS 5 H S1MnSO (1)
2 4 2 4
H SO 1FeS 5 H S1FeSO (2)
2 4 2 4
~there may be some ferrous sulfide in the steel!
H S12Ag Cl 5 Ag S12HCl or (3)
2 2
H S12AgBr 5 Ag Br12HCl or both.
2 2
Warning—Note that hydrogen sulfide is released into the room. Hydrogen sulfide is toxic and needs to be exhausted from the
room if more than a few samples are sulfur printed per 8 hour time period. If you can smell the hydrogen sulfide then an ex-
haust system is needed.
10. Sampling and Specimens
10.1 Samples are generally selected in the same manner and extent as for macroetching, as described in Methods E3, E340, and
E381. Specimens are frequently prepared to represent the entire transverse cross section, in addition, depending on the purpose of
the evaluation; the longitudinal plane may be selected, and while it is usually vertical, it may be horizontal, when required, for
example, checking near the edge of a slab.
10.2 The number, orientation, and location of specimens may be subject to producer-purchaser agreement.
10.3 Specimens should be cut in a region away from any effects from hot shearing or burning; unlike macroetching, the sulfur
print appearance is not affected by being within the heat affected zone (HAZ) which results from the torch cutting of cold steel.
10.4 Specimens can be thin enough for ease of handling, generally 12 to 25 mm thick, but may be thicker, especially if being
prepared on only one side for electrolytical macroetching after sulfur printing (40 to 50 mm thick). The surface to be contact
printed should be freshly ground until smooth, and carefully cleaned. Edges should be free of flash, burrs, or scale.
E1180 − 08 (2014)
10.5 Very smooth surfaces, such as produced by polishing, will promote slippage between the paper and disk resulting in blurred
images. A 250 micron (60 grit as packaged) finish provided by dry grinding with a hand held abrasive grit disc sander, or a contact
wheel belt sander is satisfactory. Using a face mill may leave tool marks that show up in the sulfur print. Usin
...