ASTM F326-96(2001)e2
(Test Method)Standard Test Method for Electronic Measurement for Hydrogen Embrittlement from Cadmium-Electroplating Processes
Standard Test Method for Electronic Measurement for Hydrogen Embrittlement from Cadmium-Electroplating Processes
SCOPE
1.1 This test method covers an electronic hydrogen detection instrument procedure for measurement of plating permeability to hydrogen. This method measures a variable related to hydrogen absorbed by steel during plating and to the hydrogen permeability of the plate during post plate baking. A specific application of this method is controlling cadmium-plating processes in which the plate porosity relative to hydrogen is critical, such as cadmium on high-strength steel.
1.2 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 hazard statement, see Section 8.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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e2
Designation: F 326 – 96 (Reapproved 2001)
Standard Test Method for
Electronic Measurement for Hydrogen Embrittlement From
Cadmium-Electroplating Processes
This standard is issued under the fixed designation F326; 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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Editorial corrections were made throughout the standard and in Fig. 3 in May 2001.
e NOTE—A footnote was removed editorially in August 2005.
1. Scope 3.2 Symbols:
3.2.1 HP =calibration hydrogen pressure peak.
1.1 This test method covers an electronic hydrogen detec-
3.2.2 HP =plating hydrogen pressure peak.
p
tion instrument procedure for measurement of plating perme-
3.2.3 I =probe cathode emission current.
abilitytohydrogen.Thismethodmeasuresavariablerelatedto E
3.2.4 I =probe hydrogen pressure.
H
hydrogen absorbed by steel during plating and to the hydrogen
3.2.5 I =integral of I curve from probe on to HP.
permeability of the plate during post plate baking. A specific g H
3.2.6 lambda =time in seconds for hydrogen pressure
application of this method is controlling cadmium-plating
peak to drop to half its value.
processes in which the plate porosity relative to hydrogen is
3.2.7 l=lambda obtained from a calibration run.
critical, such as cadmium on high-strength steel.
3.2.8 l =lambda obtained from a plating run.
p
1.2 This standard does not purport to address all of the
3.2.9 l =normalized test lambda, obtained as follows:
pc
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- l 5l 40/l! (1)
~
pc p
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. For specific hazard
3.2.10 l¯ =arithmetic average of normalized lambdas for
pc
statement, see Section 8.
a set of tests.
1.3 The values stated in SI units are to be regarded as the
3.2.11 range =difference between maximum l and mini-
pc
standard. The values given in parentheses are for information
mum l for a given set of tests.
pc
only.
3.2.12 run =calibration or plating of a probe.
3.2.13 test =single evaluation of a plating solution for
2. Referenced Documents
hydrogen embrittlement determination; run using a previously
2.1 ASTM Standards:
calibrated probe.
D1193 Specification for Reagent Water
3.2.14 set of tests—all consecutive tests on a plating solu-
F519 Test Method for Mechanical Hydrogen Embrittle-
tion for a given operator-instrument-day evaluation.
mentEvaluationofPlatingProcessesandServiceEnviron-
3.2.15 window—test surface of a probe described in Fig.
ments
1(A).
3. Terminology
4. Summary of Test Method
3.1 Definitions of Terms Specific to This Standard:
4.1 This method uses a metal-shelled vacuum probe as an
3.1.1 hydrogen pressure peak—the maximum hydrogen
ion gage to evaluate electrodeposited cadmium characteristics
pressure value (see I ) obtained when the probe is heated
H
relative to hydrogen permeation.After calibration, a section of
following calibration, plating, or fluid testing.
the probe shell is electroplated at the lowest current density
encountered in the cadmium electroplating process. During the
subsequent baking of the probe at a closely controlled tem-
This test method is under the jurisdiction of ASTM Committee F07 on
perature, the probe ion current, proportional to hydrogen
Aerospace andAircraft and is the direct responsibility of Subcommitteee F07.04 on
Hydrogen Embrittlement.
pressure,isrecordedasafunctionoftime.Fromthesedataand
Current edition approved Oct. 10, 1996. Published December 1996. Originally
the calibration data of the probe, a number related to the
e1
published as F326–78. Last previous edition F326–78(1995) .
2 porosity of the electroplated metal relative to hydrogen is
Annual Book of ASTM Standards, Vol 11.01.
obtained.
Annual Book of ASTM Standards, Vol 15.03.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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F 326 – 96 (2001)
FIG. 1 Probe Configuration
4.2 During the initial part of the bakeout, hydrogen contin- 6.2 Oven—The oven warms the probe to increase the
ues to diffuse through the metal shell of the probe and the ion hydrogen diffusion rate into the probe. Oven parameters are
current increases. Within a short time, however, a maximum selected by apparatus manufacturer to provide a standard
current is observed and then falls off as hydrogen is driven out reading for all hydrogen detection instruments.
of the system. 6.3 Oven Stopper—Stopper covering the oven opening.
4.3 Observations of the ion current-time curve indicate that Remove 10 s before inserting the probe.
theslopeofthecurvehasanempiricalrelationshipwithfailure 6.4 Window—The window is the unpainted, bare steel
data on stress rupture specimens such as those in Test Method portion of the probe, 0.63 6 0.03 in. in height, that is plated in
F519. For this method, I and l variables (see Section 3) must the solution under test. The window is shown in Fig. 1.
g
be empirically correlated with results from the stress rupture 6.5 Abrasive Blast—Abrasive blast window area in the
specimens. This gives a quick means of measuring ease of same way, using the same media, as used for the parts. Probe
baking hydrogen out of cadmium-electroplated parts. should be rotated while being blasted to provide uniform
4.4 Before an electroplating test, calibration is accom- surface.
plished by electrolyzing the probe in a standard solution and 6.6 Electronic Bakeout Unit—This heats the probe electri-
bakingittodetermine I and loftheunplatedsteelshellofthe cally to remove hydrogen absorbed into the probe after testing.
g
probe. May be part of hydrogen detection instrument.
5. Significance and Use
7. Reagents and Materials
5.1 Hydrogen is evolved during metal electrodeposition in
7.1 Reagents:
aqueous baths. Some of this hydrogen enters parts during
7.1.1 Purity of Reagents—Reagentgradechemicalsshallbe
plating. If the absorbed hydrogen is at a level presenting
used in all tests. Unless otherwise indicated, it is intended that
embrittlement hazards to high-strength steel, it is removed by
all reagents conform to the specifications of the Committee on
baking parts after plating to expel this hydrogen. However, the
Analytical Reagents of theAmerican Chemical Society where
lack of plate porosity itself may block hydrogen egress. Thus,
such specifications are available. Other grades may be used,
it becomes important to know both the relative amount of
provided it is first ascertained that the reagent is of sufficient
hydrogen absorbed and the plate porosity.
high purity to permit its use without lessening the accuracy of
5.2 This test provides a quantitative control number for the determination.
cadmium plate porosity that can be used to control a cadmium
7.1.2 Acetone (C H O), technical.
3 6
plating process and the status of cadmium-plated hardware. It 7.1.3 Anode Cleaning Solution—Concentrated nitric acid
can also be used for plating process troubleshooting and
(HNO ), reagent grade.
research and development to determine the effects on plate
7.1.4 Cadmium Stripping Solution—Ammonium Nitrate
porosity by process variables, contaminants, and materials.
(125 g/L)—Dissolve 125 g of ammonium nitrate (NH NO ,
4 3
When used to control a critical process, control numbers for
technical) in water and dilute to 1 L. Use at room temperature.
plate porosity must be determined by correlation with stress
7.1.5 Calibration Solution—Sodium Cyanide (50 g/L) Plus
rupture specimens or other acceptable standards.
Sodium Hydroxide (50 g/L)—Dissolve 50 g of sodium hydrox-
5.3 There is no prime standard for plate porosity. For this
ide(NaOH)inwater.Add50gofsodiumcyanide(NaCN)and
reason, two ovens must be used, with tests alternated between
dissolve. Dilute to 1 L. Use at 18 to 27°C (65 to 80°F).
ovens. Data from the ovens are compared to ensure no
equipment change has occurred.
Reagent Chemicals, American Chemical Society Specifications, American
6. Apparatus
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
6.1 Hydrogen Detection Instrument—A system consisting
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
of a control unit, two special ovens, auxiliary heater, recorder,
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
test probes, and associated equipment. MD.
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F 326 – 96 (2001)
7.1.6 Water, Distilled or Deionized, minimum electrical 12. Procedure
resistivity 50000 V·cm (for example, Specification D1193).
12.1 Bakeout of Probe:
7.2 Materials:
12.1.1 Strip cadmium-plated probes in stripping solution
7.2.1 Anodes (Calibration), solid-carbon arc rods, 5.1- to
(7.1.4) and rinse in 50°C (122°F) water for 2 min before
12.7-mm (0.20- to 0.50-in.) diameter.
bakeout.
7.2.2 Anodes (Plating), cadmium rods, A-A-51126 6.4 to
12.1.2 Insertaprobeintothesocketofanelectronicbakeout
12.7 mm (0.25 to 0.50 in.) thick, round or square.
unit.
7.2.3 Polytetrafluoroethylene (PTFE) Tape—The tape
12.1.3 Within30s,theheatershouldstabilizeorbeadjusted
should be appropriate for use in solution, width about 12 to 19
to 86.5 6 16.5 mA. If the heater does not register current, the
mm, thickness small enough to seal.
probe is defective and must be discarded.
7.2.4 Glass 1-L Beaker.
12.1.4 Bake out the probe for the time required to meet the
limits in 12.2. Do not continuously bake out probes for longer
8. Hazards
than2hto preclude damaging paint.
8.1 Sodium cyanide, cyanide, cadmium, nitric acid, and
12.2 Probe Checkout—Probes that are new, or have been
acetone can be health hazards. Use adequate face, hands, and
calibrated or plated and stripped, need to be baked out to meet
respiratory protection commensurate with standards estab-
checkout requirements as follows:
lished by American Conference of Government and Industrial
12.2.1 Hot Probe:
Hygiene for these chemicals.
12.2.1.1 Set the range to 10.
9. Sampling
NOTE 1—Here and throughout the specification, range settings are for
full-scale reading.
9.1 Stir plating bath to ensure homogeneity. The plating
bath sample must be representative of the bath. Obtain the 12.2.1.2 Removetheprobefromtheelectronicbakeoutunit;
plug into the socket assembly and 15 6 1 s after removal from
sample from beneath the surface of the bath, not by skimming
the surface. Chemical constituents must be within normal the bakeout unit, turn the probe on.
12.2.1.3 Observe the peak value of I . If less than 1,
operating range.
H
proceed with surface activation. If it is greater than 1.0, screw
10. Preparation of Apparatus
on the cap and insert probe into the oven.
12.2.1.4 If I is 0.5 or less within 5 min of inserting the
10.1 Plug in instrument and allow sufficient time for war-
H
mup. probe into the oven, proceed to surface preparation. If the
probe does not drop to I =0.5 or less with 5 min, bake out
10.2 Turn on the oven and allow 4 h for warmup.
H
10.3 Leave the instrument on continuously. again. If three successive bakeouts do not reduce I to 0.5 or
H
less within 5 min of insertion into the oven, discard the probe.
10.4 Clean contaminated anodes in cleaning solution,
(7.1.3) until heavy gassing is observed. (Warning—See Sec- 12.2.1.5 Set the instrument to read I . Probe I should read
E E
6.0 6 0.2 mA. If I does not read or cannot be adjusted to this,
tion 8.)
E
the probe or the instrument is defective. Check the instrument
11. Calibration of Apparatus
with other probes to determine which is defective. Discard
11.1 Calibration Position, 1.08 6 0.2 A/dm (10 6 2 defective probes.
A/ft )—Use nominal dimensions of Fig. 1(A) for current 12.2.2 Cold Probe:
calculations. 12.2.2.1 Set the range to 1.0.
11.2 Plating Position, 62 % of Current—Set plating cur- 12.2.2.2 Plug the probe into socket assembly and turn on.
rent density at the minimum value allowed by the plating 12.2.2.3 Observe the peak value of I . If less than 0.2,
H
specification. proceed to surface preparation. If greater than 0.2, insert into
11.3 Probe Current, I,6 6 0.2 mA.
the oven.
e
11.4 Electronic Probe Bakeout, 100 6 10 mA. 12.2.2.4 Proceed as in 12.2.1, 12.2.1.4, and 12.2.1.5.
−7
11.5 Probe I : 1 I unit=10 A
12.3 SurfacePreparation—Beforetheprobewindowprepa-
H H
Linearity, 62% full scale within each ration, check to ensure the window width and height above the
range, 1 to 10000 probe base meet the requirements of Fig. 1(A). The probes
11.6 Ovens—Ovens are calibrated by the manufacturers having windows out of limits must be cleaned and repainted in
against standard ovens that in turn were calibrated with accordance with the suppliers’ instructions or discarded.
notched tension specimen data. Oven stability is checked by 12.3.1 Mask the probe to meet the requirement of Fig. 1(B)
comparing ovens against each other in duplicate tests. using conforming masks, supplied with instruments or PTFE
11.7 Correlation of Ovens—To correlate ovens, determine adhesive tape. Edges of masks must coincide with edges of
l¯ for all tests of a set (except tests discarded in accordance window with no paint being visible. Protect the base of the
pc
with 13.4.4). From l¯ and the number of tests, determine D probe. Remove abrasive dust from the rubber masks to avoid
pc
from Fig. 2. Separate data and compute l¯ for each oven. Let paint damage.
pc
l¯ (A) be the higher value and l¯ (B) the lower value. Where 12.3.2 For processes using current densities under 4.32
pc pc
2 2
l¯ (A)− l¯ (B) is less than D, the ovens are comparable. A/dm (40A/ft ),useproductionequipmenttoblastproduction
pc pc
Where l¯ (A)− l¯ (B) is greater than D, the ovens are not parts. For processes with higher current densities, use labora-
pc pc
comparable. toryblastequipment.Dryabrasiveblastthewindowareaofthe
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F 326 – 96 (2001)
FIG. 2 Oven-Correlation Limit
probe. Use material, size, air pressures, and distances repre- carbon anodes, (7.2.1) equally spaced and rigidly mounted to
sentative of production blasting. Dry abrasive blast before fit snugly inside the beaker.
calibration may be in a laboratory cabinet.
12.4.2 Record the solution temperature to within 61°C
(62°F). The temperature must be 18 to 27°C (65 to 80°F).
NOTE 2—Someproductionfacilitiesmaynotbeadaptabletoblastingof
probes. Special procedures will need to be approved by the procuring 12.4.3 Place range selector switch t
...
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