1、Designation:B24299(Reapproved 2014)1Endorsed by AmericanElectroplaters SocietyEndorsed by NationalAssociation of Metal FinishersStandard Guide forPreparation of High-Carbon Steel for Electroplating1This standard is issued under the fixed designation B242;the number immediately following the designat
2、ion indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTESection reference was corrected editorially in
3、September 2015.1.Scope1.1 This guide is intended as an aid in establishing andmaintaining a preparatory cycle for electroplating on high-carbon steel(Note 1)producing a minimum of hydrogenembrittlement and maximum adhesion of the electrodepositedmetal.For the purpose of this guide,steels containing
4、0.35%of carbon or more,and case-hardened low-carbon steel,aredefined as high-carbon steels.There is no generally recognizeddefinite carbon content dividing high from low-carbon steelsfor electroplating purposes.NOTE1Electroplating of plain high-carbon steel introduced problemsnot found in similar op
5、erations on low-carbon steel.During the cleaningand electroplating cycle,high-carbon steel differs from low-carbon steel inregard to its greater tendency to become embrittled and the greaterdifficulty in obtaining maximum adhesion of the electrodeposit.Thepreparation of low-carbon steel for electrop
6、lating is covered in PracticeB183.1.2 This guide does not apply to the electroplating of alloysteel.For methods of chromium electroplating directly on steelsee Guide B177.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 Th
7、is standard does not purport to address all of thesafety problems associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.For a specific hazards statement,se
8、e3.1.2.Referenced Documents2.1 ASTM Standards:2B177 Guide for Engineering Chromium ElectroplatingB183 Practice for Preparation of Low-Carbon Steel forElectroplatingB849 Specification for Pre-Treatments of Iron or Steel forReducing Risk of Hydrogen EmbrittlementB850 Guide for Post-Coating Treatments
9、of Steel for Reduc-ing the Risk of Hydrogen Embrittlement3.Reagents3.1 Purity of ReagentsAll acids and chemicals used in thispractice are technical grade.Acid solutions are based upon thefollowing assay materials:Hydrochloric acid(HCl)31 mass%,density 1.16 g/mLNitric acid(HNO3)67 mass%,density 1.40
10、g/mLSulfuric acid(H2SO4)93 mass%,density 1.83 g/mL(WarningDilute sulfuric acid by slowly adding it to theapproximate amount of water required with rapid mixing.Aftercooling,bring the mixture to exact volume.)3.2 Purity of WaterUse ordinary industrial or potablewater for preparing solutions and rinsi
11、ng.4.Nature of Steel4.1 HardnessHigh hardness is a major cause of crackingof the steel during or after electroplating.The recommendedmaximum hardness range for classes of products depends ontheir geometry and service requirements(Note 2).Parts hard-ened by heat treatment should be inspected before e
12、lectroplat-ing for the presence of cracks by a suitable method,such asmagnetic or fluorescent powder inspection.1This guide is under the jurisdiction of ASTM Committee B08 on Metallic andInorganic Coatings and is the direct responsibility of Subcommittee B08.02 on PreTreatment.Current edition approv
13、ed Nov.1,2014.Published November 2014.Originallyapproved in 1949.Last previous edition approved in 2009 as B242 99(2009).DOI:10.1520/B0242-99R14E01.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards v
14、olume 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 NOTE2Some examples of parts and Rockwell hardness ranges are asfollows:Rockwell Hard-ness RangeSpringsC45 to
15、 C48Spring washersC45 to C53Small instrument partsC52 to C55Parts to be chromium electroplatedC57 to C62for engineering use4.2 Hydrogen EmbrittlementDifficulties resulting fromhydrogen embrittlement increase with increasing hardness,whether produced by heat treatment or cold work.Difficulties,during
16、 or after electroplating of hardened high-carbon steelparts,may in some cases be minimized without materialchange in hardness by baking before final pretreatment.For alisting of such hydrogen embrittlement relief bake cycles,consult Guide B850.4.3 Surface OxidationIn order that subsequent treatmentsbe facilitated,every reasonable precaution should be takenthroughout the processing to limit oxidation or scale formation.In particular cases pre-electroplating with copper to a mini-mum thickness of
