ASTM F1113-87(2011)
(Test Method)Standard Test Method for Electrochemical Measurement of Diffusible Hydrogen in Steels (Barnacle Electrode)
Standard Test Method for Electrochemical Measurement of Diffusible Hydrogen in Steels (Barnacle Electrode)
SIGNIFICANCE AND USE
The critical level of hydrogen in steels is that hydrogen which can build up to high concentrations at points of high triaxial stress causing embrittlement of the steel which can lead to catastrophic damage. This hydrogen can enter by various means, such as during pickling and electroplating. Means of reducing this hydrogen during processing are given in Specification B766 and Practices B183 and B242. It is still necessary, however, to know how effective these methods are. Though the ultimate reason for measuring this hydrogen is to relate it to embrittlement, this is not within the scope of this test method. As susceptibility to hydrogen embrittlement is a function of alloy type, heat treatment, intended use,and so forth, the tolerance for hydrogen must be determined by the user according to Method F519.
Though the actual hydrogen concentration is not determined in this test method, the current densities have been shown to be useful as an indication of relative hydrogen concentrations (1-3), and therefore the degree of hydrogen embrittlement (1,2). Thus, measurements can be compared to one another (see 4.1 and 7.1).
This test method is applicable as a quality control tool for processing (such as to monitor plating and baking) or to measure hydrogen uptake caused by corrosion.
This test method is nondestructive; however, if there is a coating, it must be removed by a method which has been demonstrated to neither damage the steel nor introduce hydrogen to make the measurement.
This test method is also applicable to situations producing continuous hydrogen permeation, such as high pressure hydrogen cylinders or corrosion processes. The results, however, would require a different treatment and interpretation (4).
This test method is also applicable to small parts, such as fasteners. The technique, procedure, and interpretation would, however, have to be altered.
Use of this test method on austenitic stainless steels and other face centered cubic (FCC) a...
SCOPE
1.1 This test method covers the procedure for measuring diffusible hydrogen in steels by an electrochemical method.
1.2 This test method is limited to carbon or alloy steels, excluding austenitic stainless steels.
1.3 This test method is limited to flat specimens to which the cell can be attached (see 4.6 and 4.8).
1.4 This test method describes testing on bare or plated steel after the plate has been removed (see 4.4).
1.5 This test method is limited to measurements at room temperature, 20 to 25°C (68 to 77°F).
1.6 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.
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Designation: F1113 − 87 (Reapproved 2011)
Standard Test Method for
Electrochemical Measurement of Diffusible Hydrogen in
Steels (Barnacle Electrode)
This standard is issued under the fixed designation F1113; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Summary of Test Method
1.1 This test method covers the procedure for measuring 3.1 A hydrogen-containing part is made the anode in an
diffusible hydrogen in steels by an electrochemical method. electrochemical cell. The diffusible (atomic) hydrogen, which
comes to the metal-electrolyte interface, is oxidized to protons
1.2 This test method is limited to carbon or alloy steels,
+ + −
(H );H combineswithhydroxylions(OH )intheelectrolyte
excluding austenitic stainless steels.
toformwater.Theoxidationcurrentismeasuredandrelatedto
1.3 This test method is limited to flat specimens to which
the hydrogen concentration.
the cell can be attached (see 4.6 and 4.8).
4. Significance and Use
1.4 Thistestmethoddescribestestingonbareorplatedsteel
after the plate has been removed (see 4.4). 4.1 The critical level of hydrogen in steels is that hydrogen
which can build up to high concentrations at points of high
1.5 This test method is limited to measurements at room
triaxialstresscausingembrittlementofthesteelwhichcanlead
temperature, 20 to 25°C (68 to 77°F).
to catastrophic damage. This hydrogen can enter by various
1.6 This standard does not purport to address all of the
means, such as during pickling and electroplating. Means of
safety concerns, if any, associated with its use. It is the
reducing this hydrogen during processing are given in Speci-
responsibility of the user of this standard to establish appro-
fication B766 and Practices B183 and B242. It is still
priate safety and health practices and determine the applica-
necessary, however, to know how effective these methods are.
bility of regulatory limitations prior to use.
Though the ultimate reason for measuring this hydrogen is to
relateittoembrittlement,thisisnotwithinthescopeofthistest
2. Referenced Documents
method. As susceptibility to hydrogen embrittlement is a
2.1 ASTM Standards:
function of alloy type, heat treatment, intended use,and so
B183Practice for Preparation of Low-Carbon Steel for
forth, the tolerance for hydrogen must be determined by the
Electroplating
user according to Method F519.
B242Guide for Preparation of High-Carbon Steel for Elec-
4.2 Though the actual hydrogen concentration is not deter-
troplating
mined in this test method, the current densities have been
B766Specification for Electrodeposited Coatings of Cad-
shown to be useful as an indication of relative hydrogen
mium
concentrations (1-3), and therefore the degree of hydrogen
D1193Specification for Reagent Water
embrittlement (1,2). Thus, measurements can be compared to
F519Test Method for Mechanical Hydrogen Embrittlement
one another (see 4.1 and 7.1).
Evaluation of Plating/Coating Processes and Service En-
4.3 This test method is applicable as a quality control tool
vironments
for processing (such as to monitor plating and baking) or to
G3Practice for Conventions Applicable to Electrochemical
measure hydrogen uptake caused by corrosion.
Measurements in Corrosion Testing
4.4 This test method is nondestructive; however, if there is
a coating, it must be removed by a method which has been
This test method is under the jurisdiction of ASTM Committee F07 on
demonstrated to neither damage the steel nor introduce hydro-
Aerospace andAircraft and is the direct responsibility of Subcommittee F07.04 on
Hydrogen Embrittlement. gen to make the measurement.
Current edition approved Dec. 1, 2011. Published August 2012. Originally
4.5 This test method is also applicable to situations produc-
approved in 1987. Last previous edition approved in 2005 as F1113 – 87 (2005).
DOI: 10.1520/F1113-87R11. ing continuous hydrogen permeation, such as high pressure
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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 Boldfacenumbersinparenthesesrefertothelistofreferencesattheendofthis
the ASTM website. standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1113 − 87 (2011)
hydrogen cylinders or corrosion processes. The results,
however,wouldrequireadifferenttreatmentandinterpretation
(4).
4.6 This test method is also applicable to small parts, such
as fasteners. The technique, procedure, and interpretation
would, however, have to be altered.
4.7 Use of this test method on austenitic stainless steels and
other face centered cubic (FCC) alloys would require different
measurement times and interpretation of results because of
differing kinetics.
4.8 Thistestmethodcanbeusedonslightlycurvedsurfaces
as long as the gasket defines a reproducible area. The area
calculation must, however, be changed.
5. Apparatus
5.1 Cell—A photo and drawing of a typical cell, which has
been found to be acceptable for hydrogen measurements, are
shown in Figs. 1 and 2, respectively.
5.1.1 Thecellismadeofanonmetallicmaterialthatwillnot
react with or contaminate the solution. The side opening has a
recess to accommodate the silicone rubber gasket.
FIG. 2 Engineering Drawing of Cell (3)
5.1.2 Gasket, silicone rubber, shall provide a reproducible
solution-contact area with the specimen, preferably 1.0 cm .
5.1.3 Cell Holder, a cradle-like C-clamp. Other clamping
devices can be used if necessary, such as for larger parts.
5.1.4 Cathode,anickel/nickeloxideelectrode.Itismadeby
removingthepositiveplatefromanickel/cadmiumbatteryand
attachinganickelwireorfoil.Theareaofthiscathodeshallbe
approximately five times that of the anode.
5.1.5 Anode—The anode is the specimen.
5.1.6 The cell is left open to the atmosphere. No purging is
used.
5.2 Current Measuring Device—The current can be mea-
sured by any method that will not affect its value. A zero
resistance ammeter (5), a current follower (6), and the current
measuring system shown in Fig. 3 (1) have been found to be
acceptable. The following description refers to Fig. 3.
5.2.1 Standard Resistor, connected across the cell through a
switch.
FIG. 1 Photograph of Cell FIG. 3 Schematic of Measuring Apparatus (1)
F1113 − 87 (2011)
5.2.2 Electrometer, to determine the current by measuring 8.1.2 The Ni/NiO electrode is made the anode, that is,
the voltage drop across the resistor. A 10-kΩ resistor with an connected to the positive terminal of the charging source.Any
electrometer having an input impedance of 10 Ω and a 1-mA conductor that will not react with the solution, such as
output has been found to be satisfactory. platinum, graphite, or steel, may be used as the cathode.
5.2.3 Strip Chart Recorder, to monitor the electrometer
8.2 Determine the specimen contact area which is outlined
output. A recorder having an input resistance of 100 kΩ has
by the gasket.
been found to be satisfactory.
8.2.1 Assemble the cell with a smooth piece of aluminum
5.2.4 Timer, accurate to within 10 s in a 30-min run.
sheet or foil, at least 0.04 mm thick, between a specimen and
the gasket. The Ni/NiO electrode is not needed.
6. Reagents
8.2.2 Fill the cell with 0.2M NaOH solution and allow the
6.1 Purity of Reagents—Reagent grade chemicals shall be
aluminum to be etched by the alkaline solution for about 20
used in all tests. Unless otherwise indicated, it is intended that
min.
all reagents shall conform to the specifications of the Commit-
8.2.3 Dismantle the cell and rinse well. A properly as-
tee onAnalytical Reagents of theAmerican Chemical Society,
sembled cell will produce a sharply defined, circular etch (see
where such specifications are available. Other grades may be
Fig. 4).
used, provided it is first ascertained that the reagent is of
8.2.4 Measure the diameter of the etched circle under a
sufficiently high purity to permit its use without lessening the
microscope (10×), and calculate the area (see 10.2).
accuracy of the determination.
8.2.5 A poor gasket or improper tightening of the cell will
6.2 Purity of Water—Distilled or deionized water conform- be detected by this procedure. Overtightening will produce a
ing to Specification D1193, Type IV, shall be used to prepare
deformation of the gasket, resulting in an out-of-round etch.
all solutions. Undertightening, or a worn-out gasket, will cause crevices,
resulting in etching under the gasket (see Fig. 4).
6.3 Sodium Hydroxide Solution (0.2M)—Dissolve8gof
sodium hydroxide (NaOH) pellets in water and dilute to 1 L.
8.3 Measure uncoated coupons, prepared in accordance
with 7.1, to determine the background current density. Keep
6.4 Ammonium Nitrate Solution (120 g/L)—Dissolve 120 g
these coupons desiccated for at least one week before
of ammonium nitrate (NH NO ) in water and dilute to 1 L.
4 3
measuring, to assure that no hydrogen, as a result of corrosion,
6.5 Methyl Alcohol (CH OH).
is produced, and to allow any hydrogen in the specimens to
6.6 Ethyl Alcohol (C H OH).
escape.
2 5
NOTE 2—The background measurement is used only as a reference to
7. Test Specimens
indicate the presence or absence of hydrogen. It is not used in any
7.1 The test specimen can be a coupon of 1- to 6-mm calculation.
thickness or an actual part. If it is a coupon, it shall be of the
same alloy, form, temper/condition, and surface finish as the 9. Procedure
NOTE 3—This procedure pertains to cadmium-plated specimens. Any
part. The specimen shall be of sufficient size to accommodate
other plating must be removable by a method that will neither damage the
the cell and of sufficient smoothness and flatness to prevent
steel nor introduce hydrogen.
leakingoftheelectrolyteunderthegasket(see8.2).Ifpossible,
9.1 Specimen Preparation:
specimens shall be of sufficient size for a duplicate measure-
ment to be made (see 9.4).
NOTE 4—The time to prepare the specimen must take no longer than 5
min.
8. Calibration and Standardization
9.1.1 Remove any cadmium plate from an area on one side
8.1 Calibrate the nickel/nickel oxide (Ni/NiO) electrode
of the specimen large enough to accommodate the cell (ap-
against a saturated calomel electrode (SCE) in 0.2M NaOH.A
proximately 40 by 40 mm) by swabbing with ammonium
freshly charged Ni/NiO electrode will be at least 350 mV
nitrate solution. Rinse with water and dry. Swabs made of
positive to the SCE when measured according to Practice G3.
polyurethane foam or cotton have been found to be satisfac-
It shall be recharged when its potential is less than 300 mV
tory.
positive to the SCE.
NOTE 1—Repeated use of the Ni/NiO electrode will cause a temporary
drain of the charge. To prevent this from happening, alternate two
electrodes during a series of measurements.
8.1.1 ChargetheNi/NiOelectrodeina0.2MNaOHsolution
for ⁄2 h at a current density of 5 to 10 mA/cm .
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
FIG. 4 Etched Areas (NaOH on Al) Showing (A) Good Gasket Fit
listed by the American Chemical Society, seeAnalar Standards for Laboratory
Chemicals,BDHLtd.,Poole,Dorset,U.K.,andtheUnited States Pharmacopeia and and (B) Poor Fit Showing Undercutting of Gasket as a Result of
National Formulary,U.S.PharmacopeialConvention,Inc.(USPC),Rockville,MD. Undertightening or Worn Gasket
F1113 − 87 (2011)
9.1.2 Abrade the surface lightly with an aluminum oxide-
impregnated nylon cleaning pad to remove surface contamina-
tion and to provide a reproducible surface finish. Wipe clean
using a tissue wet with methyl or ethyl alcohol.
9.2 Cell Assembly:
NOTE 5—The time to assemble the cell and start the measurement must
take no longer than 5 min. The total time from the start of 9.1.1 – 9.3.1
must take no longer than 10 min.
9.2.1 Clamp the Cell to the Specimen.
NOTE 6—The cell should be clamped only tight enough to prevent
leakage. Overtightening will cause deformation of the gasket. Proper
tightening can be determined by following the procedure in 8.2.
9.2.2 Clamp the Ni/NiO electrode in the center of the cell
cavity using the cell dimensions of Fig. 1. For other cell
designs, the distance between the electrodes shall be 25 mm.
9.2.3 Connect the resistor and switch between the Ni/NiO
electrode and the specimen.
9.2.4 Connecttheelectrometeracrosstheresistorsothatthe
Ni/NiO electrode will measure positive and the steel negative.
9.2.5 Connect the recorder to the electrometer output.
9.2.6 Fill the cell with 0.2M NaOH, making sure that the
Ni/NiO electrode and the specimen measurement area are
completely covered with solution.
9.3 Making the Measurement:
NOTE 7—The measurement must be started within 1 min of filling the
cell.
9.3.1 Simultaneously turn on the cell switch and the timer.
NOTE 8—The oxidation current decreases with time. During the
FIG. 5 Recorder Tracings Showing (A) Good Measurement, (B )
measurement, it will change by a few orders of magnitude. Therefore, for
Acceptable Measurement, and (C ), Poor Measurement Which
the first 5 min, set the recorder at an appropriate high setting to prevent
Must Be Repeated
overload. The final readings will be in the microampere range.Adjust the
electrometer and recorder accordingly.
full-scale voltage on the strip chart recorder is 10 mV and the
9.3.2 Record the current at the end of 30 min. This shall be
resistance is 10 kΩ, then the full-scale current is 1 µA.
referred to as the 30-min reading.
10.2 Calculate the contact area from the diameter of the
NOTE 9—The current measurement must always be made for the same
length of time. In this test method, 30 min has been chosen. The reasons etched surface (see 8.2). The diameter, D, should be measured
for this are given in references (1,3).
in two directions and averaged. If it has been established that
the contact area is essentially round, the area, A, is given by:
9.3.3 Turn off the switch.
9.3.4 Dismantle the cell, rinse, and dry. A=π (D/2) . For example, if the average diameter is found to
2 2
be 1.2 cm, the area is 3.14 (1.2/2) or 1.10 cm .
9.4 Repeat Measurements:
10.3 Current density is the current per unit area. For
NOTE 10—If the recorder tracing is poor (see Fig. 5), a repeat
example,ifthe30-mincurrentis0.66µA,andtheexposedarea
measurement must be made.
2 2
is 1.1 cm , then the curren
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