ASTM B614-95(2000)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:B614–95 (Reapproved 2000)
Standard Practice for
Descaling and Cleaning Zirconium and Zirconium Alloy
Surfaces
This standard is issued under the fixed designation B 614; 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.
1. Scope 4.2.3. When electrolytic systems are employed, the voltage
should be controlled to prevent the occurrence of spark
1.1 This practice covers a cleaning and descaling procedure
discharge and subsequent pitting.
useful to producers, users, and fabricators of zirconium and
zirconiumalloysfortheremovalofordinaryshopsoils,oxides,
3. Blast Cleaning
and scales resulting from heat treatment operations and foreign
3.1 Mechanical descaling methods such as sandblasting,
substances present as surface contaminants.
shot blasting, and vapor blasting may be used to remove hot
1.2 It is not intended that these procedures become manda-
work scales and lubricants from zirconium surfaces if followed
tory for removal of any of the indicated soils but rather serve
by thorough conditioning and cleaning as described in Section
as a guide when zirconium and zirconium alloys are being
4.
processed in the wrought, cast, or fabricated form.
3.2 Aluminum oxide, silicon carbide, silica sand, zircon
1.3 It is the intent that these soils be removed prior to
sand, and steel grit are acceptable media for mechanical
chemical milling, joining, plating, fabrication, and in any
descaling.Periodicreplacementofusedmediamayberequired
situation where foreign substances interfere with the corrosion
to avoid excessive working by dull particulate.
resistance, stability, and quality of the finished product.
3.3 Roughening of exposed surface areas may occur from
1.4 The values stated in inch-pound units are to be regarded
grit or shot if cleaning of the entire surface is accomplished by
as the standard.
blasting. Partial cleaning for preserving the surface finish is to
1.5 This standard does not purport to address all of the
be preferred in conjunction with proper pickling procedures.
safety concerns, if any, associated with its use. It is the
3.4 Any abrasive or shot blast cleaning may induce residual
responsibility of the user of this standard to establish appro-
compressivestressesinthesurfaceofthematerialorzirconium
priate safety and health practices and determine the applica-
structure. Warpage may occur in sections that are subsequently
bility of regulatory limitations prior to use. For specific hazard
chemical milled or contour machined.
statements, see Section 6.
3.5 In most cases, blast cleaning is not intended to eliminate
2. Processing Soil Removal pickling procedures completely. However, there are cases
whereblastcleaningdoesnotneedtobefollowedbyapickling
2.1 Grease, oil, and lubricants employed in machining,
operation. Abrasives may not remove surface layers contami-
forming, and fabricating operations on zirconium and zirco-
nated with interstitial elements such as carbon, oxygen, hydro-
nium alloys should be removed by employing one of the
gen, and nitrogen. When these elements are present in exces-
methods or a combination of methods as listed: (1) alkaline or
sive amounts, they are preferably removed by controlled acid
emulsion soak-type cleaners, (2) ultrasonic cleaning, (3) ac-
pickling in accordance with 4.3.
etone or trichloroethylene solvent washing or vapor degreas-
ing, or (4) electrolytic alkaline cleaning system. In the electro-
4. Pickling and Descaling
lytic system, the work can be either anodic or cathodic polarity
4.1 Recommendedposttreatmentofshotorabrasiveblasted
provided voltage and current density are controlled to avoid
zirconium surfaces may include acid pickling as described in
anodizing. Removal of these soils is recommended prior to
4.3 to ensure complete removal of metallic iron, oxide, scale,
heat treatment or application of acid treatment designated in
and other surface contaminants.
4.2 Scale and lubricant residues developed on mill, foundry,
This practice is under the jurisdiction of ASTM Committee B10 on Reactive forged, or fabricated zirconium products usually require con-
and Refractory Metals and Alloysand is the direct responsibility of Subcommittee
ditioning by one of the following commercial methods prior to
B10.02 on Zirconium and Hafnium.
final pickling as described in 4.3 to produce a completely
Current edition approved Aug. 15, 1995. Published October 1995. Originally
e1
scale-free surface.
published as B 614 – 77. Last previous edition B 614 – 77 (1989) .
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
B614
absorption during pickling is minimized.
4.2.1 Proprietary solutions of caustic- or organic-based
NOTE 5—The components should be rinsed immediately and thor-
compounds in tap water in accordance with the manufacturer’s
oughly in cold tap water following pickling to avoid staining of the
recommendation.
surfaces with residual fluorides or chlorides which may be detrimental in
4.2.2 Molten alkaline-based salt baths operating at 1200 to
some services.
1300°F (649 to 704°C) in accordance with prescribed proce-
NOTE 6—In the processing of zirconium mill products and fabrications,
dures.
an oxygen-rich layer is unavoidable where there is a combined exposure
4.2.3 Oxides and heat tints developed below 1000°F
to high temperatures and an oxidizing atmosphere. In the removal of this
oxygen-richlayerbypicklinginstrongsolutionsofnitricandhydrofluoric
(538°C) can frequently be remov
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