ASTM F1113-87(2005)e1

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Designation:F1113–87(Reapproved2005)
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.
´ NOTE—Editorial changes were made throughout in June 2005.
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
1.2 This test method is limited to carbon or alloy steels, comes to the metal-electrolyte interface, is oxidized to protons
+ + −
excluding austenitic stainless steels. (H ); H combines with hydroxyl ions (OH ) in the electrolyte
1.3 This test method is limited to flat specimens to which toformwater.Theoxidationcurrentismeasuredandrelatedto
the cell can be attached (see 4.6 and 4.8). the hydrogen concentration.
1.4 Thistestmethoddescribestestingonbareorplatedsteel
4. Significance and Use
after the plate has been removed (see 4.4).
1.5 This test method is limited to measurements at room 4.1 The critical level of hydrogen in steels is that hydrogen
which can build up to high concentrations at points of high
temperature, 20 to 25°C (68 to 77°F).
1.6 This standard does not purport to address all of the triaxialstresscausingembrittlementofthesteelwhichcanlead
to catastrophic damage. This hydrogen can enter by various
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- means, such as during pickling and electroplating. Means of
reducing this hydrogen during processing are given in Speci-
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. fication B766 and Practices B183 and B242. It is still neces-
sary, however, to know how effective these methods are.
2. Referenced Documents
Though the ultimate reason for measuring this hydrogen is to
2.1 ASTM Standards: relateittoembrittlement,thisisnotwithinthescopeofthistest
B183 Practice for Preparation of Low-Carbon Steel for method. As susceptibility to hydrogen embrittlement is a
Electroplating function of alloy type, heat treatment, intended use,and so
B242 Guide for Preparation of High-Carbon Steel for Elec- forth, the tolerance for hydrogen must be determined by the
troplating user according to Method F519.
B766 Specification for Electrodeposited Coatings of Cad- 4.2 Though the actual hydrogen concentration is not deter-
mium mined in this test method, the current densities have been
D1193 Specification for Reagent Water shown to be useful as an indication of relative hydrogen
F519 TestMethodforMechanicalHydrogenEmbrittlement concentrations (1-3), and therefore the degree of hydrogen
Evaluation of Plating/Coating Processes and Service Envi- embrittlement (1,2). Thus, measurements can be compared to
ronments one another (see 4.1 and 7.1).
G3 Practice for ConventionsApplicable to Electrochemical 4.3 This test method is applicable as a quality control tool
Measurements in Corrosion Testing for processing (such as to monitor plating and baking) or to
measure hydrogen uptake caused by corrosion.
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
gen to make the measurement.
Hydrogen Embrittlement.
Current edition approved June 1, 2005. Published June 2005. Originally
4.5 This test method is also applicable to situations produc-
approved in 1987. Last previous edition approved in 1999 as F1113–87 (1999).
ing continuous hydrogen permeation, such as high pressure
DOI: 10.1520/F1113-87R05E01.
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.
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F1113–87 (2005)
hydrogen cylinders or corrosion processes. The results, how-
ever, would require a different treatment and interpretation (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—Aphoto 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.
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
FIG. 2 Engineering Drawing of Cell (3)
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.
5.2.2 Electrometer, to determine the current by measuring
the voltage drop across the resistor. A 10-kV resistor with an
electrometer having an input impedance of 10 V and a 1-mA
output has been found to be satisfactory.
FIG. 1 Photograph of Cell FIG. 3 Schematic of Measuring Apparatus (1)
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F1113–87 (2005)
5.2.3 Strip Chart Recorder, to monitor the electrometer 8.2.1 Assemble the cell with a smooth piece of aluminum
output. A recorder having an input resistance of 100 kV has sheet or foil, at least 0.04 mm thick, between a specimen and
been found to be satisfactory. the gasket. The Ni/NiO electrode is not needed.
5.2.4 Timer, accurate to within 10 s in a 30-min run. 8.2.2 Fill the cell with 0.2M NaOH solution and allow the
aluminum to be etched by the alkaline solution for about 20
6. Reagents
min.
6.1 Purity of Reagents—Reagent grade chemicals shall be 8.2.3 Dismantle the cell and rinse well. A properly as-
used in all tests. Unless otherwise indicated, it is intended that
sembled cell will produce a sharply defined, circular etch (see
all reagents shall conform to the specifications of the Commit- Fig. 4).
tee onAnalytical Reagents of theAmerican Chemical Society,
8.2.4 Measure the diameter of the etched circle under a
where such specifications are available. Other grades may be microscope (103), and calculate the area (see 10.2).
used, provided it is first ascertained that the reagent is of
8.2.5 A poor gasket or improper tightening of the cell will
sufficiently high purity to permit its use without lessening the be detected by this procedure. Overtightening will produce a
accuracy of the determination.
deformation of the gasket, resulting in an out-of-round etch.
6.2 Purity of Water—Distilled or deionized water conform- Undertightening, or a worn-out gasket, will cause crevices,
ing to Specification D1193, Type IV, shall be used to prepare resulting in etching under the gasket (see Fig. 4).
all solutions. 8.3 Measure uncoated coupons, prepared in accordance
6.3 Sodium Hydroxide Solution (0.2M)—Dissolve8gof with 7.1, to determine the background current density. Keep
sodium hydroxide (NaOH) pellets in water and dilute to 1 L.
these coupons desiccated for at least one week before measur-
6.4 Ammonium Nitrate Solution (120 g/L)—Dissolve 120 g ing, to assure that no hydrogen, as a result of corrosion, is
of ammonium nitrate (NH NO ) in water and dilute to 1 L.
produced, and to allow any hydrogen in the specimens to
4 3
6.5 Methyl Alcohol (CH OH). escape.
6.6 Ethyl Alcohol (C H OH).
2 5
NOTE 2—The background measurement is used only as a reference to
indicate the presence or absence of hydrogen. It is not used in any
7. Test Specimens
calculation.
7.1 The test specimen can be a coupon of 1- to 6-mm
9. Procedure
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
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-
NOTE 4—The time to prepare the specimen must take no longer than 5
ment to be made (see 9.4).
min.
8. Calibration and Standardization
9.1.1 Remove any cadmium plate from an area on one side
of the specimen large enough to accommodate the cell (ap-
8.1 Calibrate the nickel/nickel oxide (Ni/NiO) electrode
proximately 40 by 40 mm) by swabbing with ammonium
against a saturated calomel electrode (SCE) in 0.2M NaOH.A
nitrate solution. Rinse with water and dry. Swabs made of
freshly charged Ni/NiO electrode will be at least 350 mV
polyurethane foam or cotton have been found to be satisfac-
positive to the SCE when measured according to Practice G3.
tory.
It shall be recharged when its potential is less than 300 mV
9.1.2 Abrade the surface lightly with an aluminum oxide-
positive to the SCE.
impregnated nylon cleaning pad to remove surface contamina-
NOTE 1—Repeated use of the Ni/NiO electrode will cause a temporary
tion and to provide a reproducible surface finish. Wipe clean
drain of the charge. To prevent this from happening, alternate two
using a tissue wet with methyl or ethyl alcohol.
electrodes during a series of measurements.
9.2 Cell Assembly:
8.1.1 ChargetheNi/NiOelectrodeina0.2MNaOHsolution
NOTE 5—Thetimetoassemblethecellandstartthemeasurementmust
for ⁄2 h at a current density of 5 to 10 mA/cm .
takenolongerthan5min.Thetotaltimefromthestartof9.1.1-9.3.1must
8.1.2 The Ni/NiO electrode is made the anode, that is,
take no longer than 10 min.
connected to the positive terminal of the charging source.Any
conductor that will not react with the solution, such as
platinum, graphite, or steel, may be used as the cathode.
8.2 Determine the specimen contact area which is outlined
by the gasket.
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
FIG. 4 Etched Areas (NaOH on Al) Showing (A) Good Gasket Fit
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, and (B) Poor Fit Showing Undercutting of Gasket as a Result of
MD. Undertightening or Worn Gasket
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F1113–87 (2005)
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 mea-
surement, it will change by a few orders of magnitude. Therefore, for the
first 5 min, set the recorder at an appropriate high setting to prevent
overload. The final readings will be in the microampere range.Adjust the
electrometer and recorder accordingly.
9.3.2 Record the current at the end of 30 min. This shall be
referred to as the 30-min reading.
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
for this are given in references (1,3).
FIG. 5 Recorder Tracings Showing (A) Good Measurement, (B )
Acceptable Measurement, and (C ), Poor Measurement Which
9.3.3 Turn off the switch.
Must Be Repeated
9.3.4 Dismantle the cell, rinse, and dry.
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.
is 1.1 cm , then the current density is 0.66/1.1 or 0.60µ A/cm
9.4.1 If cadmium-plated coupons or parts are of sufficient
2.
size, make duplicate measurements on the same specimen,
either alongside or opposite to the first in accordance with 9.1. 11. Interpretation of Results
Ifalongside,thenewlyswabbedareashallnotoverlapthefirst.
11.1 The30-mincurrentdensitywilldependonthematerial
Thespecimenpreparationprocedurein9.1.1mustbestartedno
as w
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