ASTM_F_326_-_96_2012.pdf

Designation:F32696(Reapproved 2012)Standard Test Method forElectronic Measurement for Hydrogen Embrittlement FromCadmium-Electroplating Processes1This standard is issued under the fixed designation F326;the number immediately following the designation indicates the year of originaladoption or,in the case of revision,the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers an electronic hydrogen detec-tion instrument procedure for measurement of plating perme-ability to hydrogen.This method measures a variable related tohydrogen absorbed by steel during plating and to the hydrogenpermeability of the plate during post plate baking.A specificapplication of this method is controlling cadmium-platingprocesses in which the plate porosity relative to hydrogen iscritical,such as cadmium on high-strength steel.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.For specific hazardstatement,see Section 8.1.3 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterF519 Test Method for Mechanical Hydrogen EmbrittlementEvaluation of Plating/Coating Processes and Service En-vironments3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 hydrogen pressure peakthe maximum hydrogenpressure value(see IH)obtained when the probe is heatedfollowing calibration,plating,or fluid testing.3.2 Symbols:3.2.1HP=calibration hydrogen pressure peak.3.2.2 HPp=plating hydrogen pressure peak.3.2.3 IE=probe cathode emission current.3.2.4 IH=probe hydrogen pressure.3.2.5 I=integral of IHcurve from probe on to HP.3.2.6 lambda=time in seconds for hydrogen pressure peakto drop to half its value.3.2.7 =lambda obtained from a calibration run.3.2.8 p=lambda obtained from a plating run.3.2.9 pc=normalized test lambda,obtained as follows:pc5 p40/!(1)3.2.10 pc=arithmetic average of normalized lambdas for aset of tests.3.2.11 range=difference between maximum pcand mini-mum pcfor a given set of tests.3.2.12 run=calibration or plating of a probe.3.2.13 test=single evaluation of a plating solution forhydrogen embrittlement determination;run using a previouslycalibrated probe.3.2.14 set of testsall consecutive tests on a plating solu-tion for a given operator-instrument-day evaluation.3.2.15 windowtest surface of a probe described in Fig.1(A).4.Summary of Test Method4.1 This method uses a metal-shelled vacuum probe as anion gage to evaluate electrodeposited cadmium characteristicsrelative to hydrogen permeation.After calibration,a section ofthe probe shell is electroplated at the lowest current densityencountered in the cadmium electroplating process.During thesubsequent baking of the probe at a closely controlledtemperature,the probe ion current,proportional to hydrogenpressure,is recorded as a function of time.From these data andthe calibration data of the probe,a number related to theporosity of the electroplated metal relative to hydrogen isobtained.4.2 During the initial part of the bakeout,hydrogen contin-ues to diffuse through the metal shell of the probe and the ion1This test method is under the jurisdiction of ASTM Committee F07 onAerospace and Aircraft and is the direct responsibility of Subcommitteee F07.04 onHydrogen Embrittlement.Current edition approved Nov.1,2012.Published November 2012.Originallyapproved in 1978.Last previous edition approved in 2006 as F326 96(2006).DOI:10.1520/F0326-96R12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 current increases.Within a short time,however,a maximumcurrent is observed and then falls off as hydrogen is driven outof the system.4.3 Observations of the ion current-time curve indicate thatthe slope of the curve has an empirical relationship with failuredata on stress rupture specimens such as those in Test MethodF519.For this method,Iand variables(see Section 3)mustbe empirically correlated with results from the stress rupturespecimens.This gives a quick means of measuring ease ofbaking hydrogen out of cadmium-electroplated parts.4.4 Before an electroplating test,calibration is accom-plished by electrolyzing the probe in a standard solution andbaking it to determine Iand of the unplated steel shell of theprobe.5.Significance and Use5.1 Hydrogen is evolved during metal electrodepo