1、Designation:A380/A380M13Standard Practice forCleaning,Descaling,and Passivation of Stainless SteelParts,Equipment,and Systems1This standard is issued under the fixed designation A380/A380M;the number immediately following the designation indicates the yearof original adoption or,in the case of revis
2、ion,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.Scope*1.1 This practice covers rec
3、ommendations and precautionsfor cleaning,descaling,and passivating of new stainless steelparts,assemblies,equipment,and installed systems.Theserecommendations are presented as procedures for guidancewhen it is recognized that for a particular service it is desiredto remove surface contaminants that
4、may impair the normalcorrosion resistance,or result in the later contamination of theparticular stainless steel grade,or cause product contamination.The selection of procedures from this practice to be applied tothe parts may be specified upon agreement between thesupplierandthepurchaser.Forcertaine
5、xceptionalapplications,additional requirements which are not covered bythis practice may be specified upon agreement between thesupplier and the purchaser.Although they apply primarily tomaterials in the composition ranges of the austenitic,ferritic,and martensitic stainless steels,the practices des
6、cribed mayalso be useful for cleaning other metals if due consideration isgiven to corrosion and possible metallurgical effects.1.1.1 The term passivation is commonly applied to severaldistinctly different operations or processes relating to stainlesssteels.In order to avoid ambiguity in the setting
7、 ofrequirements,it may be necessary for the purchaser to defineprecisely the intended meaning of passivation.Some of thevarious meanings associated with the term passivation that arein common usage include the following:1.1.1.1 Passivation is the process by which a stainless steelwill spontaneously
8、form a chemically inactive surface whenexposed to air or other oxygen-containing environments.It wasat one time considered that an oxidizing treatment was neces-sary to establish this passive film,but it is now accepted thatthis film will form spontaneously in an oxygen-containingenvironment providi
9、ng that the surface has been thoroughlycleaned or descaled.1.1.1.2 Passivation is removal of exogenous iron or ironcompounds from the surface of a stainless steel by means of achemical dissolution,most typically by a treatment with anacid solution that will remove the surface contamination butwill n
10、ot significantly affect the stainless steel itself.Thisprocess is described in a general way in 6.2.11 and definedprecisely in 6.4 with further reference to the requirements ofAnnex A2 and Part II of the table on acid cleaning of steel.Unless otherwise specified,it is this definition of passivationt
11、hat is taken as the meaning of a specified requirement forpassivation.1.1.1.3 Passivation is the chemical treatment of a stainlesssteel with a mild oxidant,such as a nitric acid solution,for thepurpose of enhancing the spontaneous formation of the protec-tive passive film.Such chemical treatment is
12、generally notnecessary for the formation of the passive film.1.1.1.4 Passivation does not indicate the separate process ofdescaling as described in Section 5,although descaling may benecessary before passivation can be effective.1.2 This practice does not cover decontamination or clean-ing of equipm
13、ent or systems that have been in service,nor doesit cover descaling and cleaning of materials at the mill.On theother hand,some of the practices may be applicable for thesepurposes.While the practice provides recommendations andinformation concerning the use of acids and other cleaning anddescaling
14、agents,it cannot encompass detailed cleaning proce-dures for specific types of equipment or installations.Ittherefore in no way precludes the necessity for careful planningand judgment in the selection and implementation of suchprocedures.1.3 These practices may be applied when free iron,oxidescale,
15、rust,grease,oil,carbonaceous or other residual chemicalfilms,soil,particles,metal chips,dirt,or other nonvolatiledeposits might adversely affect the metallurgical or sanitarycondition or stability of a surface,the mechanical operation ofa part,component,or system,or contaminate a process fluid.The d
16、egree of cleanness required on a surface depends on theapplication.In some cases,no more than degreasing or removalof gross contamination is necessary.Others,such as food-handling,pharmaceutical,aerospace,and certain nuclearapplications,may require extremely high levels of cleanness,1This practice is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.14 on Methods of Corrosion Testing.Current edition approv
