ASTM A380-06
(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
ABSTRACT
This practice covers the standard recommendations and precautions for cleaning, descaling, and passivating of new stainless steel parts, assemblies, equipment, and installed systems. Consideration shall be given in the design of parts, equipment, and systems that will require cleaning to minimize the presence of areas in which dirt, or cleaning solutions might become trapped, and to provide for effective circulation and removal of cleaning solutions. Materials shall be precleaned. Scales shall be removed through chemical descaling, acid pickling, and mechanical descaling. Degreasing and general cleaning shall be accomplished by immersion in, swabbing with, or spraying with alkaline, emulsion, chelate, acid, solvent, or detergent cleaners or a combination of these; by vapor degreasing; by ultrasonics using various cleaners; by steam, with or without a cleaner; or by high-pressure water-jetting. Recommended cleaning practices shall be followed for welds and weld-joint areas, specially critical applications, installed systems and post-erections. The following shall be used as the basis for cleanness acceptability: Visual inspection; wipe tests; residual pattern; water-break test; free iron test such as water-wetting or drying; high-humidity test; and copper sulfate test. Precision inspection shall be performed by solvent-ring test, black light inspection, atomizer test, and ferroxyl test. Precaution shall always be practiced to minimize iron contamination, in reuse of cleaning and pickling solution, in water rinsing, in circulation of cleaning solutions and rinse water, in protection of cleaned surfaces, for safety, and disposal of used solutions and water.
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:
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.
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 stainlees steel itself. This process is described in a general way in and defined precisely in with further reference to the requirements of and Part II of the table on acid cleaning of steel. Unless otherwise specified, it is...
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Designation: A380 − 06
StandardPractice for
Cleaning, Descaling, and Passivation of Stainless Steel
1
Parts, Equipment, and Systems
This standard is issued under the fixed designation A380; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber 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* acid solution that will remove the surface contamination but
will not significantly affect the stainlees steel itself. This
1.1 This practice covers recommendations and precautions
process is described in a general way in 6.2.11 and defined
for cleaning, descaling, and passivating of new stainless steel
precisely in 6.4 with further reference to the requirements of
parts, assemblies, equipment, and installed systems. These
Annex A2 and Part II of the table on acid cleaning of steel.
recommendations are presented as procedures for guidance
Unless otherwise specified, it is this definition of passivation
when it is recognized that for a particular service it is desired
that is taken as the meaning of a specified requirement for
to remove surface contaminants that may impair the normal
passivation.
corrosion resistance, or result in the later contamination of the
1.1.1.3 Passivation is the chemical treatment of a stainless
particularstainlesssteelgrade,orcauseproductcontamination.
steel with a mild oxidant, such as a nitric acid solution, for the
For certain exceptional applications, additional requirements
purpose of enhancing the spontaneous formation of the protec-
which are not covered by this practice may be specified upon
tive passive film. Such chemical treatment is generally not
agreement between the manufacturer and the purchaser. Al-
necessary for the formation of the passive film.
though they apply primarily to materials in the composition
ranges of the austenitic, ferritic, and martensitic stainless
1.1.1.4 Passivation does not indicate the separate process of
steels, the practices described may also be useful for cleaning
descalingasdescribedinSection5,althoughdescalingmaybe
other metals if due consideration is given to corrosion and
necessary before passivation can be effective.
possible metallurgical effects.
1.2 This practice does not cover decontamination or clean-
1.1.1 The term passivation is commonly applied to several
ingofequipmentorsystemsthathavebeeninservice,nordoes
distinctly different operations or processes relating to stainless
it cover descaling and cleaning of materials at the mill. On the
steels. In order to avoid ambiguity in the setting of
other hand, some of the practices may be applicable for these
requirements, it may be necessary for the purchaser to define
purposes. While the practice provides recommendations and
precisely the intended meaning of passivation. Some of the
informationconcerningtheuseofacidsandothercleaningand
various meanings associated with the term passivation that are
descaling agents, it cannot encompass detailed cleaning proce-
in common usage include the following:
dures for specific types of equipment or installations. It
1.1.1.1 Passivation is the process by which a stainless steel
thereforeinnowayprecludesthenecessityforcarefulplanning
will spontaneously form a chemically inactive surface when
and judgment in the selection and implementation of such
exposedtoairorotheroxygen-containingenvironments.Itwas
procedures.
at one time considered that an oxidizing treatment was neces-
sary to establish this passive film, but it is now accepted that
1.3 These practices may be applied when free iron, oxide
this film will form spontaneously in an oxygen-containing
scale,rust,grease,oil,carbonaceousorotherresidualchemical
environment providing that the surface has been thoroughly
films, soil, particles, metal chips, dirt, or other nonvolatile
cleaned or descaled.
deposits might adversely affect the metallurgical or sanitary
1.1.1.2 Passivation is removal of exogenous iron or iron
condition or stability of a surface, the mechanical operation of
compounds from the surface of a stainless steel by means of a
a part, component, or system, or contaminate a process fluid.
chemical dissolution, most typically by a treatment with an
The degree of cleanness required on a surface depends on the
application.Insomecases,nomorethandegreasingorremoval
1
of gross contamination is necessary. Others, such as food-
This practice is under the jurisdiction of ASTM Committee A01 on Steel,
Stainless Steel and RelatedAlloysand is the direct responsibility of Subcommittee
handling, pharmaceutical, aerospace, and certain nuclear
A01.14 on Methods of Corrosion Testing.
ap
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