Standard Practice for Descaling and Cleaning Zirconium and Zirconium Alloy Surfaces

ABSTRACT
This practice covers a cleaning and de-scaling procedure useful to producers, users, and fabricators of zirconium and zirconium alloys for the removal of ordinary shop soils, oxides, and scales resulting from heat treatment operations and foreign substances present as surface contaminants. Grease, oil, and lubricants employed in machining, forming, and fabricating operations on zirconium and zirconium alloys should be removed by employing one of the methods or a combination of methods: alkaline or emulsion soak-type cleaners, ultrasonic cleaning, acetone, citrus based cleaners, or safety solvent immersion washing or vapor degreasing, or electrolytic alkaline cleaning system. Mechanical de-scaling methods such as sandblasting, shot blasting, and vapor blasting may be used to remove hot work scales and lubricants from zirconium surfaces if followed by thorough conditioning and cleaning. Aluminum oxide, silicon carbide, silica sand, zircon sand, and steel grit are acceptable media for mechanical de-scaling. Recommended post treatment of shot or abrasive blasted zirconium surfaces may include acid pickling to ensure complete removal of metallic iron, oxide, scale, and other surface contaminants. Visual inspection of material cleaned in accordance with this practice should show no evidence of paint, oil, grease, glass, graphite, lubricant, scale, abrasive, iron, or other forms of contamination.
SCOPE
1.1 This practice covers a cleaning and descaling procedure useful to producers, users, and fabricators of zirconium and zirconium alloys for the removal of ordinary shop soils, oxides, and scales resulting from heat treatment operations and foreign substances present as surface contaminants.  
1.2 It is not intended that these procedures become mandatory for removal of any of the indicated soils but rather serve as a guide when zirconium and zirconium alloys are being processed in the wrought, cast, or fabricated form.  
1.3 It is the intent that these soils be removed prior to chemical milling, joining, plating, welding, fabrication, and in any situation where foreign substances interfere with the corrosion resistance, stability, and quality of the finished product.  
1.4 Unless a single unit is used, for example, solution concentrations in g/l, the values stated in either inch-pound or SI units are to be regarded separately as standard. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. SI values cannot be mixed with inch-pound values.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Sections 3 and 7.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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Status
Published
Publication Date
31-Mar-2021
Current Stage
Ref Project

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ASTM B614-16(2021) - Standard Practice for Descaling and Cleaning Zirconium and Zirconium Alloy Surfaces
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: B614 − 16 (Reapproved 2021)
Standard Practice for
Descaling and Cleaning Zirconium and Zirconium Alloy
Surfaces
This standard is issued under the fixed designation B614; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This practice covers a cleaning and descaling procedure
2.1 NFPA Standard:
useful to producers, users, and fabricators of zirconium and
NFPA 484 Standard for Combustible Metals
zirconiumalloysfortheremovalofordinaryshopsoils,oxides,
and scales resulting from heat treatment operations and foreign
3. Processing Soil Removal
substances present as surface contaminants.
3.1 Grease, oil, and lubricants employed in machining,
1.2 It is not intended that these procedures become manda- forming, and fabricating operations on zirconium and zirco-
tory for removal of any of the indicated soils but rather serve nium alloys should be removed by employing one of the
as a guide when zirconium and zirconium alloys are being
methods or a combination of methods as listed: (1) alkaline or
processed in the wrought, cast, or fabricated form. emulsion soak-type cleaners, (2) ultrasonic cleaning, (3)
acetone, citrus based cleaners, or safety solvent immersion
1.3 It is the intent that these soils be removed prior to
washing or vapor degreasing, or (4) electrolytic alkaline
chemical milling, joining, plating, welding, fabrication, and in
cleaning system. In the electrolytic system, the work can be
any situation where foreign substances interfere with the
either anodic or cathodic polarity provided voltage and current
corrosion resistance, stability, and quality of the finished
density are controlled to avoid anodizing. Removal of these
product.
soils is recommended prior to heat treatment or application of
1.4 Unless a single unit is used, for example, solution acid treatment designated in Section 5. When electrolytic
concentrations in g/l, the values stated in either inch-pound or systems are employed, the voltage should be controlled to
SI units are to be regarded separately as standard. The values
prevent the occurrence of spark discharge and subsequent
stated in each system are not exact equivalents; therefore, each pitting. The use of trichloroethylene is not prohibited and can
system must be used independently of the other. SI values
be used; however its use is hazardous enough to preclude it as
cannot be mixed with inch-pound values. a recommended solvent in this standard. Care must be exer-
cised when using chemical solvents. There are hazards associ-
1.5 This standard does not purport to address all of the
ated with their use, such as flammability, carcinogenicity, and
safety concerns, if any, associated with its use. It is the
ozone depletion (see 7.1).
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
4. Blast Cleaning
mine the applicability of regulatory limitations prior to use.
4.1 Mechanical descaling methods such as sandblasting,
For specific hazard statements, see Sections 3 and 7.
shot blasting, and vapor blasting may be used to remove hot
1.6 This international standard was developed in accor-
work scales and lubricants from zirconium surfaces if followed
dance with internationally recognized principles on standard-
by thorough conditioning and cleaning as described in Section
ization established in the Decision on Principles for the
5.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4.2 Aluminum oxide, silicon carbide, silica sand, zircon
Barriers to Trade (TBT) Committee.
sand, and steel grit are acceptable media for mechanical
descaling.Periodicreplacementofusedmediamayberequired
to avoid excessive working of the metal surface by dull
1 particulate.
This practice is under the jurisdiction of ASTM Committee B10 on Reactive
and Refractory Metals and Alloys and is the direct responsibility of Subcommittee
B10.02 on Zirconium and Hafnium.
Current edition approved April 1, 2021. Published April 2021. Originally
approved in 1977. Last previous edition approved in 2016 as B614 – 16. DOI: Available from National Fire Protection Association (NFPA), 1 Batterymarch
10.1520/B0614-16R21. Park, Quincy, MA 02269, http://www.nfpa.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B614 − 16 (2021)
4.3 Roughening of exposed surface areas may occur from 5.2.3 Oxides and heat tints developed below 1000°F
grit or shot if cleaning of the entire surface is accomplished by (540°C) can frequently be removed by pickling in a nitric acid
blasting. Partial cleaning for preserving the surface finish is to
– hydrofluoric acid solution. Common input acid strengths
be preferred in conjunction with proper pickling procedures.
used are 70 % by weight for HNO acid and 48 % by weight
for HF acid. HF acid at 60 % strength has been used in the past
4.4 Any abrasive or shot blast cleaning may induce residual
but there are additional transportation restrictions on this
compressivestressesinthesurfaceofthematerialorzirconium
structure. Warpage may occur in sections that are subsequently higher strength acid.
chemical milled or contour machined.
5.2.4 The pickling acid solution is composed of 25 to 50 %
by volume of 70 % strength HNO acid and 3.8 to 8.8 % by
4.5 In most cases, blast cleaning is not intended to eliminate
volume of 48 % strength HF acid. The balance is clean filtered
pickling procedures completely. However, there are cases
whereblastcleaningdoesnotneedtobefollowedbyapickling water. This yields a solution having 350 to 700 mg/L of nitric
operation. Abrasives may not remove surface layers contami- acidand36to84mg/Lofhydrofluoricacid.Picklingshouldbe
nated with interstitial elements such as carbon, oxygen,
done in a solution with a temperature less than 120°F (50°C)
hydrogen, and nitrogen. When these elements are present in
and preferably nearer to 90°F (30°C).
excessive amounts, they are preferably removed by controlled
5.2.5 Abrasive methods such as wheel or belt grinding,
acid pickling in accordance with 5.3.
high-speed tool steel or carbide grinding, or both, segmented
flapper wheels, and grit or shot blasting, when available, may
5. Pickling and Descaling
beusedwhensurfaceconfigurationissuchthatthescaledareas
5.1 Recommendedposttreatmentofshotorabrasiveblasted
are readily acces
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