ASTM A380-99e1
(Practice)Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems
Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems
SCOPE
1.1 This practice covers recommendations and precautions for cleaning, descaling, and passivating of new stainless steel parts, assemblies, equipment, and installed systems. These recommendations are presented as procedures for guidance when it is recognized that for a particular service it is desired to remove surface contaminants that may impair the normal corrosion resistance, or result in the later contamination of the particular stainless steel grade, or cause product contamination. For certain exceptional applications, additional requirements which are not covered by this practice may be specified upon agreement between the manufacturer and the purchaser. Although they apply primarily to materials in the composition ranges of the austenitic, ferritic, and martensitic stainless steels, the practices described may also be useful for cleaning other metals if due consideration is given to corrosion and possible metallurgical effects.
1.1.1 The term passivation is commonly applied to several distinctly different operations or processes relating to stainless steels. In order to avoid ambiguity in the setting of requirements, it may be necessary for the purchaser to define precisely the intended meaning of passivation. Some of the various meanings associated with the term passivation that are in common usage include the following:
1.1.1.1 Passivation is the process by which a stainless steel will spontaneously form a chemically inactive surface when exposed to air or other oxygen-containing environments. It was at one time considered that an oxidizing treatment was necessary to establish this passive film, but it is now accepted that this film will form spontaneously in an oxygen-containing environment providing that the surface has been thoroughly cleaned or descaled.
1.1.1.2 Passivation is removal of exogenous iron or iron compounds from the surface of a stainless steel by means of a chemical dissolution, most typically by a treatment with an acid solution that will remove the surface contamination but will not significantly affect the stainless steel itself. This process is described in a general way in 6.2.11 and defined precisely in 6.4 with further reference to the requirements of Annex A2 and Table A2.1, Part II. Unless otherwise specified, it is this definition of passivation that is taken as the meaning of a specified requirement for passivation.
1.1.1.3 Passivation is the chemical treatment of a stainless steel with a mild oxidant, such as a nitric acid solution, for the purpose of enhancing the spontaneous formation of the protective passive film. Such chemical treatment is generally not necessary for the formation of the passive film.
1.1.1.4 Passivation does not indicate the separate process of descaling as described in Section 5, although descaling may be necessary before passivation can be effective.
1.2 This practice does not cover decontamination or cleaning of equipment or systems that have been in service, nor does it cover descaling and cleaning of materials at the mill. On the other hand, some of the practices may be applicable for these purposes. While the practice provides recommendations and information concerning the use of acids and other cleaning and descaling agents, it cannot encompass detailed cleaning procedures for specific types of equipment or installations. It therefore in no way precludes the necessity for careful planning and judgment in the selection and implementation of such procedures.
1.3 These practices may be applied when free iron, oxide scale, rust, grease, oil, carbonaceous or other residual chemical films, soil, particles, metal chips, dirt, or other nonvolatile deposits might adversely affect the metallurgical or sanitary condition or stability of a surface, the mechanical operation of a part, component, or system, or contaminate a process fluid. The degree of cleanness required on a surface depends on the application. In some cases, no more than...
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e1
Designation:A 380–99
Standard Practice for
Cleaning, Descaling, and Passivation of Stainless Steel
1
Parts, Equipment, and Systems
This standard is issued under the fixed designation A 380; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) 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
e NOTE—Table A2.1 was corrected editorially in January 2000.
1. Scope 1.1.1.2 Passivation is removal of exogenous iron or iron
compounds from the surface of a stainless steel by means of a
1.1 This practice covers recommendations and precautions
chemical dissolution, most typically by a treatment with an
for cleaning, descaling, and passivating of new stainless steel
acid solution that will remove the surface contamination but
parts, assemblies, equipment, and installed systems. These
will not significantly affect the stainlees steel itself. This
recommendations are presented as procedures for guidance
process is described in a general way in 6.2.11 and defined
when it is recognized that for a particular service it is desired
precisely in 6.4 with further reference to the requirements of
to remove surface contaminants that may impair the normal
Annex A2 and Part II of the table on acid cleaning of steel.
corrosion resistance, or result in the later contamination of the
Unless otherwise specified, it is this definition of passivation
particularstainlesssteelgrade,orcauseproductcontamination.
that is taken as the meaning of a specified requirement for
For certain exceptional applications, additional requirements
passivation.
which are not covered by this practice may be specified upon
1.1.1.3 Passivation is the chemical treatment of a stainless
agreement between the manufacturer and the purchaser. Al-
steel with a mild oxidant, such as a nitric acid solution, for the
though they apply primarily to materials in the composition
purpose of enhancing the spontaneous formation of the protec-
ranges of the austenitic, ferritic, and martensitic stainless
tive passive film. Such chemical treatment is generally not
steels, the practices described may also be useful for cleaning
necessary for the formation of the passive film.
other metals if due consideration is given to corrosion and
1.1.1.4 Passivation does not indicate the separate process of
possible metallurgical effects.
descaling as described in Section 5, although descaling may be
1.1.1 The term passivation is commonly applied to several
necessary before passivation can be effective.
distinctly different operations or processes relating to stainless
1.2 This practice does not cover decontamination or clean-
steels. In order to avoid ambiguity in the setting of require-
ingofequipmentorsystemsthathavebeeninservice,nordoes
ments, it may be necessary for the purchaser to define precisely
it cover descaling and cleaning of materials at the mill. On the
the intended meaning of passivation. Some of the various
other hand, some of the practices may be applicable for these
meanings associated with the term passivation that are in
purposes. While the practice provides recommendations and
common usage include the following:
information concerning the use of acids and other cleaning and
1.1.1.1 Passivation is the process by which a stainless steel
descaling agents, it cannot encompass detailed cleaning proce-
will spontaneously form a chemically inactive surface when
dures for specific types of equipment or installations. It
exposedtoairorotheroxygen-containingenvironments.Itwas
thereforeinnowayprecludesthenecessityforcarefulplanning
at one time considered that an oxidizing treatment was neces-
and judgment in the selection and implementation of such
sary to establish this passive film, but it is now accepted that
procedures.
this film will form spontaneously in an oxygen-containing
1.3 These practices may be applied when free iron, oxide
environment providing that the surface has been thoroughly
scale, rust, grease, oil, carbonaceous or other residual chemical
cleaned or descaled.
films, soil, particles, metal chips, dirt, or other nonvolatile
deposits might adversely affect the metallurgical or sanitary
1
This practice is under the jurisdiction of ASTM Committee A-1 on Steel,
condition or stability of a surface, the mechanical operation of
Stainless Steel, and RelatedAlloys and is the direct responsibility of Subcommittee
a part, component, or system, or contaminate a process fluid.
A01.14 on Methods of Corrosion Testing.
The degree of cleanness required on a surface depends on the
Current edition approved Sept. 10, 1999. Published November 1999. Original
...
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