ASTM_B_912_-_02_2013.pdf

Designation:B91202(Reapproved 2013)Standard Specification forPassivation of Stainless Steels Using Electropolishing1This standard is issued under the fixed designation B912;the number immediately following the designation 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.1.Scope1.1 This specification covers the passivation of stainlesssteel alloys in the 200(UNS2XXXX),300(UNS3XXXX),and400(UNS4XXXX)series,and the precipitation-hardenedalloys,using electropolishing procedures.NOTE1Surface passivation occurs simultaneously with electropolish-ing under proper operating conditions.The quality of passivation willdepend on the type of stainless steel,the formulation of the electropol-ishing solution,and the conditions of operation.Free iron on the surfaceof the stainless steel is removed resulting in improved corrosion resis-tance.Surface smoothing obtained by electropolishing will also improvecorrosion resistance.Electropolishing will also remove heat tint and oxidescale.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This specification may involve hazardous materials,operations,and equipment.This specification does not purportto address all of the safety concerns,if any,associated with itsuse.It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2A380 Practice for Cleaning,Descaling,and Passivation ofStainless Steel Parts,Equipment,and SystemsA967 Specification for Chemical Passivation Treatments forStainless Steel PartsB117 Practice for Operating Salt Spray(Fog)ApparatusB322 Guide for Cleaning Metals Prior to ElectroplatingB374 Terminology Relating to ElectroplatingB602 Test Method for Attribute Sampling of Metallic andInorganic CoatingsD3951 Practice for Commercial Packaging2.2 ISO Standards:3ISO2080 ElectroplatingandRelatedProcessesVocabularyISO 4519 Electrodeposited Metallic Coatings and RelatedFinishesSampling Procedures for Inspection by Attri-butesISO 9227 Corrosion Tests in Artificial AtmospheresSaltSpray TestsISO 15730 Metallic and Other Inorganic CoatingsElectropolishing as a Means of Smoothing and Passivat-ing Stainless Steels3.Terminology3.1 Definitions:3.1.1 electropolishing,nelectrochemical process in whichthe article(s)to be passivated are treated anodically in asuitable acid medium.3.1.2 passivation,nrendering of a stainless steel surfaceinto a lower state of chemical reactivity.3.1.2.1 DiscussionPassivated surfaces are characterizedby the absence of free iron,as defined by Practice A380.3.2 Definitions of Terms Specific to This Standard:3.2.1 Definitions of terms in this specification can be foundin Terminology B374 and ISO 2080.4.Ordering Information4.1 When ordering articles to be electropolished in confor-mance with this standard,the purchaser shall state the follow-ing:4.1.1 Alloy DesignationWhen ordering articles passivatedin accordance with this specification,the purchaser shall state,in addition to the ASTM designation number,the date of issue,the alloy designation number,and the testing method(s)bywhich the article will be evaluated(see 5.3).4.1.2 AppearanceThe purchaser shall specify the appear-ance required,for example,bright or dull.Unless otherwisespecified by the purchaser,a bright luster shall be acceptable.Alternatively,samples showing the required finish,or range offinish,shall be supplied or approved by the purchaser.When1This specification is under the jurisdiction of ASTM Committee B08 onMetallic and Inorganic Coatings and is the direct responsibility of SubcommitteeB08.07 on Conversion Coatings.Current edition approved May 1,2013.Published May 2013.Originallyapproved in 2002.Last previous edition approved in 2008 as B912 02(2008)1.DOI:10.1520/B0912-02R13.2For 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.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 required,the basis material may be subjected,beforeelectropolishing,to such mechanical polishing as may berequired to yield the desired final surface characteristics.4.1.3 Contact MarksVisible contact marks may occur.The location of electrical contact marks shall be agreed uponbetween purchaser and supplier.4.1.4 Metal RemovalSome metal is removed from thesurface of the article during electropolishing,typically 5 to 10m.As much as 50 m may