ASTM F326-96(2006)
(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
SIGNIFICANCE AND USE
Hydrogen is evolved during metal electrodeposition in aqueous baths. Some of this hydrogen enters parts during plating. If the absorbed hydrogen is at a level presenting embrittlement hazards to high-strength steel, it is removed by baking parts after plating to expel this hydrogen. However, the lack of plate porosity itself may block hydrogen egress. Thus, it becomes important to know both the relative amount of hydrogen absorbed and the plate porosity.
This test provides a quantitative control number for cadmium plate porosity that can be used to control a cadmium plating process and the status of cadmium-plated hardware. It can also be used for plating process troubleshooting and research and development to determine the effects on plate porosity by process variables, contaminants, and materials. When used to control a critical process, control numbers for plate porosity must be determined by correlation with stress rupture specimens or other acceptable standards.
There is no prime standard for plate porosity. For this reason, two ovens must be used, with tests alternated between ovens. Data from the ovens are compared to ensure no equipment change has occurred.
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.
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
Relations
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:F326 −96(Reapproved 2006)
Standard Test Method for
Electronic Measurement for Hydrogen Embrittlement From
Cadmium-Electroplating Processes
ThisstandardisissuedunderthefixeddesignationF326;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2.1 HP =calibration hydrogen pressure peak.
3.2.2 HP =plating hydrogen pressure peak.
1.1 This test method covers an electronic hydrogen detec-
p
tion instrument procedure for measurement of plating perme- 3.2.3 I =probe cathode emission current.
E
abilitytohydrogen.Thismethodmeasuresavariablerelatedto
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.
γ H
permeability of the plate during post plate baking. A specific
3.2.6 lambda =time in seconds for hydrogen pressure peak
application of this method is controlling cadmium-plating
to drop to half its value.
processes in which the plate porosity relative to hydrogen is
3.2.7 λ=lambda obtained from a calibration run.
critical, such as cadmium on high-strength steel.
3.2.8 λ =lambda obtained from a plating run.
p
1.2 This standard does not purport to address all of the
3.2.9 λ =normalized test lambda, obtained as follows:
safety concerns, if any, associated with its use. It is the
pc
responsibility of the user of this standard to establish appro-
λ 5λ ~40/λ! (1)
pc p
priate safety and health practices and determine the applica-
¯
3.2.10 λ =arithmetic average of normalized lambdas for a
bility of regulatory limitations prior to use. For specific hazard
pc
set of tests.
statement, see Section 8.
1.3 The values stated in SI units are to be regarded as the
3.2.11 range =difference between maximum λ and mini-
pc
standard. The values given in parentheses are for information
mum λ 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.
D1193Specification for Reagent Water
3.2.14 set of tests—all consecutive tests on a plating solu-
F519Test Method for Mechanical Hydrogen Embrittlement
tion for a given operator-instrument-day evaluation.
Evaluation of Plating/Coating Processes and Service En-
vironments 3.2.15 window—test surface of a probe described in Fig.
1(A).
3. Terminology
4. Summary of Test Method
3.1 Definitions of Terms Specific to This Standard:
3.1.1 hydrogen pressure peak—the maximum hydrogen
4.1 This method uses a metal-shelled vacuum probe as an
pressure value (see I ) obtained when the probe is heated
H
ion gage to evaluate electrodeposited cadmium characteristics
following calibration, plating, or fluid testing.
relative to hydrogen permeation.After calibration, a section of
3.2 Symbols:
the probe shell is electroplated at the lowest current density
encounteredinthecadmiumelectroplatingprocess.Duringthe
subsequent baking of the probe at a closely controlled
This test method is under the jurisdiction of ASTM Committee F07 on
temperature, the probe ion current, proportional to hydrogen
Aerospace andAircraft and is the direct responsibility of Subcommitteee F07.04 on
pressure,isrecordedasafunctionoftime.Fromthesedataand
Hydrogen Embrittlement.
Current edition approved Nov. 1, 2006. Published January 2007. Originally
the calibration data of the probe, a number related to the
´2
approved in 1978. Last previous edition approved in 2001 as F326–96(2001) .
porosity of the electroplated metal relative to hydrogen is
DOI: 10.1520/F0326-96R06.
2 obtained.
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
4.2 During the initial part of the bakeout, hydrogen contin-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. ues to diffuse through the metal shell of the probe and the ion
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F326−96 (2006)
FIG. 1 Probe Configuration
current increases. Within a short time, however, a maximum 6.2 Oven—The oven warms the probe to increase the
current is observed and then falls off as hydrogen is driven out hydrogen diffusion rate into the probe. Oven parameters are
of the system. selected by apparatus manufacturer to provide a standard
reading for all hydrogen detection instruments.
4.3 Observations of the ion current-time curve indicate that
theslopeofthecurvehasanempiricalrelationshipwithfailure 6.3 Oven Stopper—Stopper covering the oven opening.
data on stress rupture specimens such as those in Test Method Remove 10 s before inserting the probe.
F519. For this method, I andλ variables (see Section 3) must
γ
6.4 Window—The window is the unpainted, bare steel
be empirically correlated with results from the stress rupture
portion of the probe, 0.63 6 0.03 in. in height, that is plated in
specimens. This gives a quick means of measuring ease of
the solution under test. The window is shown in Fig. 1.
baking hydrogen out of cadmium-electroplated parts.
6.5 AbrasiveBlast—Abrasiveblastwindowareainthesame
4.4 Before an electroplating test, calibration is accom-
way, using the same media, as used for the parts. Probe should
plished by electrolyzing the probe in a standard solution and
be rotated while being blasted to provide uniform surface.
bakingittodetermine I andλoftheunplatedsteelshellofthe
γ
6.6 Electronic Bakeout Unit—This heats the probe electri-
probe.
callytoremovehydrogenabsorbedintotheprobeaftertesting.
May be part of hydrogen detection instrument.
5. Significance and Use
5.1 Hydrogen is evolved during metal electrodeposition in
7. Reagents and Materials
aqueous baths. Some of this hydrogen enters parts during
7.1 Reagents:
plating. If the absorbed hydrogen is at a level presenting
7.1.1 Purity of Reagents—Reagent grade chemicals shall be
embrittlement hazards to high-strength steel, it is removed by
used in all tests. Unless otherwise indicated, it is intended that
baking parts after plating to expel this hydrogen. However, the
all reagents conform to the specifications of the Committee on
lack of plate porosity itself may block hydrogen egress. Thus,
Analytical Reagents of theAmerican Chemical Society where
it becomes important to know both the relative amount of
such specifications are available. Other grades may be used,
hydrogen absorbed and the plate porosity.
provided it is first ascertained that the reagent is of sufficient
5.2 This test provides a quantitative control number for
high purity to permit its use without lessening the accuracy of
cadmium plate porosity that can be used to control a cadmium
the determination.
plating process and the status of cadmium-plated hardware. It
7.1.2 Acetone (C H O), technical.
3 6
can also be used for plating process troubleshooting and
7.1.3 Anode Cleaning Solution—Concentrated nitric acid
research and development to determine the effects on plate
(HNO ), reagent grade.
porosity by process variables, contaminants, and materials.
7.1.4 Cadmium Stripping Solution—Ammonium Nitrate
When used to control a critical process, control numbers for
(125 g/L)—Dissolve 125 g of ammonium nitrate (NH NO ,
4 3
plate porosity must be determined by correlation with stress
technical) in water and dilute to 1 L. Use at room temperature.
rupture specimens or other acceptable standards.
7.1.5 Calibration Solution—Sodium Cyanide (50 g/L) Plus
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 HydrogenDetectionInstrument—Asystemconsistingof
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
acontrolunit,twospecialovens,auxiliaryheater,recorder,test
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
probes, and associated equipment. MD.
F326−96 (2006)
¯ ¯
7.1.6 Water, Distilled or Deionized, minimum electrical λ (A) be the higher value andλ (B) the lower value.Where
pc pc
¯ ¯
resistivity 50000 Ω·cm (for example, Specification D1193). λ (A)− λ (B) is less than ∆, the ovens are comparable.
pc pc
¯ ¯
Where λ (A)− λ (B) is greater than ∆, the ovens are not
pc pc
7.2 Materials:
comparable.
7.2.1 Anodes (Calibration), solid-carbon arc rods, 5.1- to
12.7-mm (0.20- to 0.50-in.) diameter.
12. Procedure
7.2.2 Anodes (Plating), cadmium rods, A-A-51126 6.4 to
12.7 mm (0.25 to 0.50 in.) thick, round or square.
12.1 Bakeout of Probe:
7.2.3 Polytetrafluoroethylene (PTFE) Tape—The tape 12.1.1 Strip cadmium-plated probes in stripping solution
should be appropriate for use in solution, width about 12 to 19
(7.1.4) and rinse in 50°C (122°F) water for 2 min before
mm, thickness small enough to seal. bakeout.
7.2.4 Glass 1-L Beaker.
12.1.2 Insertaprobeintothesocketofanelectronicbakeout
unit.
8. Hazards
12.1.3 Within30s,theheatershouldstabilizeorbeadjusted
8.1 Sodium cyanide, cyanide, cadmium, nitric acid, and to 86.5 6 16.5 mA. If the heater does not register current, the
acetone can be health hazards. Use adequate face, hands, and probe is defective and must be discarded.
respiratory protection commensurate with standards estab- 12.1.4 Bake out the probe for the time required to meet the
lished by American Conference of Government and Industrial limits in 12.2. Do not continuously bake out probes for longer
Hygiene for these chemicals. than2hto preclude damaging paint.
12.2 Probe Checkout—Probes that are new, or have been
9. Sampling
calibrated or plated and stripped, need to be baked out to meet
9.1 Stir plating bath to ensure homogeneity. The plating
checkout requirements as follows:
bath sample must be representative of the bath. Obtain the
12.2.1 Hot Probe:
sample from beneath the surface of the bath, not by skimming
12.2.1.1 Set the range to 10.
the surface. Chemical constituents must be within normal
NOTE 1—Here and throughout the specification, range settings are for
operating range.
full-scale reading.
10. Preparation of Apparatus
12.2.1.2 Removetheprobefromtheelectronicbakeoutunit;
plug into the socket assembly and 15 6 1 s after removal from
10.1 Plug in instrument and allow sufficient time for war-
the bakeout unit, turn the probe on.
mup.
12.2.1.3 Observe the peak value of I . If less than 1,
H
10.2 Turn on the oven and allow 4 h for warmup.
proceed with surface activation. If it is greater than 1.0, screw
10.3 Leave the instrument on continuously. 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
H
10.4 Clean contaminated anodes in cleaning solution,
probe into the oven, proceed to surface preparation. If the
(7.1.3) until heavy gassing is observed. (Warning—See Sec-
probe does not drop to I =0.5 or less with 5 min, bake out
H
tion 8.)
again. If three successive bakeouts do not reduce I to 0.5 or
H
11. Calibration of Apparatus less within 5 min of insertion into the oven, discard the probe.
2 12.2.1.5 Set the instrument to read I . Probe I should read
E E
11.1 Calibration Position, 1.08 6 0.2 A/dm (10 6 2
2 6.0 60.2mA.If I doesnotreadorcannotbeadjustedtothis,
E
A/ft )—Use nominal dimensions of Fig. 1(A) for current
the probe or the instrument is defective. Check the instrument
calculations.
with other probes to determine which is defective. Discard
11.2 Plating Position, 62 % of Current—Setplatingcurrent
defective probes.
density at the minimum value allowed by the plating specifi-
12.2.2 Cold Probe:
cation.
12.2.2.1 Set the range to 1.0.
11.3 Probe Current, I , 6 6 0.2 mA. 12.2.2.2 Plug the probe into socket assembly and turn on.
e
12.2.2.3 Observe the peak value of I . If less than 0.2,
H
11.4 Electronic Probe Bakeout, 100 6 10 mA.
proceed to surface preparation. If greater than 0.2, insert into
−7
11.5 Probe I : 1 I unit=10 A
H H
the oven.
Linearity, 62% full scale within each
12.2.2.4 Proceed as in 12.2.1, 12.2.1.4, and 12.2.1.5.
range, 1 to 10000
12.3 Surface Preparation—Before the probe window
11.6 Ovens—Ovens are calibrated by the manufacturers
preparation, check to ensure the window width and height
against standard ovens that in turn were calibrated with
above the probe base meet the requirements of Fig. 1(A). The
notched tension specimen data. Oven stability is checked by
probes having windows out of limits must be cleaned and
comparing ovens against each other in duplicate tests.
repainted in accordance with the suppliers’ instructions or
discarded.
11.7 Correlation of Ovens—To correlate ovens, determine
¯
λ for all tests of a set (except tests discarded in accordance 12.3.1 Mask the probe to meet the requirement of Fig. 1(B)
pc
¯
with 13.4.4). From λ and the number of tests, determine ∆ using conforming masks, supplied with instruments or PTFE
pc
¯
from Fig. 2. Separate data and compute λ for each oven. Let adhesive tape. Edges of masks must coincide with edges of
pc
F326−96 (2006)
FIG. 2Oven-Correlation Limit
window with no paint being visible. Protect the base of the Repeat Steps 12.3.1-12.3.3 as required to provide acceptable
probe. Remove abrasive dust from the rubber masks to avoid cleanliness and texture.
paint damage. 12.3.5 Proceed to the calibration run or plating run as
12.3.2 For processes using current densities under 4.32 applicable; immerse the probe within 10 min after sandblast-
2 2
A/dm (40A/ft ),useproductionequipmenttoblastproduction ing.
parts. For processes with higher current densities, use labora-
12.4 Probe Calibration:
toryblastequipment.Dryabrasiveblastthewindowareaofthe
12.4.1 Pour 850 6 50 mL(28.6 6 0.17 fl oz) of calibration
probe. Use material, size, air pressures, and distances repre-
solution (7.1.5) into a clean, dry 1-L beaker and insert four
sentative of production blasting. Dry abrasive blast before
carbon anodes, (7.2.1) equally spaced and rigidly mounted to
calibration may be in a laboratory cabinet.
fit s
...
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