ASTM B600-91(2002)e1
(Guide)Standard Guide for Descaling and Cleaning Titanium and Titanium Alloy Surfaces
Standard Guide for Descaling and Cleaning Titanium and Titanium Alloy Surfaces
ABSTRACT
This guide covers a cleaning and descaling procedure useful to producers, users, and fabricators of titanium and titanium alloys for the removal of ordinary shop soils, oxides, and scales resulting from heat treatment operations and foreign substances present as surface contaminants. It is recommended that the materials shall be subjected to soil removal prior to heat treatment or application of acid treatment. Mechanical descaling methods such as sandblasting, shot blasting, and vapor blasting may be used to remove hot work scales and lubricants from titanium surfaces. Recommended post treatment of shot or abrasive blasted titanium surfaces may include acid pickling to ensure complete removal of surface contaminants. For chemically milled materials, salt bath conditioning may be required to remove the oxygen-contaminated layer. Acid etching treatment may be required following mechanical abrading or chemical conditioning of materials to completely clean the surface.
SCOPE
1.1 This guide covers a cleaning and descaling procedure useful to producers, users, and fabricators of titanium and titanium 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 be mandatory for removal of any of the indicated soils but rather serve as a guide when titanium and titanium 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, fabrication, and in any situation where foreign substances interfere with the corrosion resistance, stability, and quality of the finished product.
1.4 Acid etching may be required following cleaning when the surface has an oxygen-contaminated layer or alpha case present.
1.5 The values stated in inch-pound units are to be regarded as the standard. The values in parentheses are for information only.
This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information.
´1
Designation:B600–91(Reapproved 2002)
Standard Guide for
Descaling and Cleaning Titanium and Titanium Alloy
Surfaces
This standard is issued under the fixed designation B600; 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.
This standard has been approved for use by agencies of the Department of Defense.
´ NOTE—Editorial changes were made in 4.2.4 and 4.3.2 in September 2006.
1. Scope mended prior to heat treatment or application of acid treatment
designated in 4.2.When electrolytic systems are employed, the
1.1 This guide covers a cleaning and descaling procedure
voltage should be controlled to prevent the occurrence of spark
useful to producers, users, and fabricators of titanium and
discharge and subsequent pitting.
titanium alloys for the removal of ordinary shop soils, oxides,
and scales resulting from heat treatment operations and foreign
3. Blast Cleaning
substances present as surface contaminants.
3.1 Mechanical descaling methods such as sandblasting,
1.2 It is not intended that these procedures be mandatory for
shot blasting, and vapor blasting may be used to remove hot
removal of any of the indicated soils but rather serve as a guide
work scales and lubricants from titanium surfaces if followed
when titanium and titanium alloys are being processed in the
by thorough conditioning and cleaning as described in Section
wrought, cast, or fabricated form.
4.
1.3 It is the intent that these soils be removed prior to
3.2 The sand used for blasting should be a high-grade,
chemical milling, joining, plating, fabrication, and in any
washed, iron-free, silica sand. If carbon or low-alloy steel
situation where foreign substances interfere with the corrosion
products are sandblasted in the same facility, the sand used for
resistance, stability, and quality of the finished product.
cleaningtheseproductsshouldnotbeusedontitaniumsurfaces
1.4 Acid etching may be required following cleaning when
and a separate sand supply should be provided.
the surface has an oxygen-contaminated layer or alpha case
3.3 Roughening of exposed surface areas may occur from
present.
grit or shot if cleaning of the entire surface is accomplished by
1.5 The values stated in inch-pound units are to be regarded
blasting. Partial cleaning for preserving the surface finish is to
as the standard. The values in parentheses are for information
be preferred in conjunction with proper pickling procedures.
only.
3.4 Blast cleaning that utilizes steel grit or sand containing
1.6 This standard does not purport to address the safety
appreciable amounts of iron should be followed by acid
concerns, if any, associated with its use. It is the responsibility
pickling to remove any embedded steel particles on the surface
of the user of this standard to consult and establish appropriate
of the titanium.
safety and health practices and determine the applicability of
3.5 Any abrasive or shot blast cleaning may induce residual
regulatory limitations prior to use.
compressive stresses in the surface of the material or titanium
2. Processing Soil Removal structure. Warpage may occur in sections that are subsequently
chemical milled or contour machined.
2.1 It is recommended that grease, oil, and lubricants
3.6 In most cases, blast cleaning is not intended to eliminate
employedinmachining,forming,andfabricatingoperationson
pickling procedures completely. Abrasives will not remove
titanium and titanium alloys be removed by alkaline or
surface layers contaminated with interstitial elements such as
emulsion soak-type cleaners and electrolytic alkaline cleaning
carbon, oxygen, and nitrogen.When these elements are present
systems. In the electrolytic system the work may be either
in excessive amounts, they are preferably removed by con-
anodic or cathodic polarity. Removal of these soils is recom-
trolled acid pickling in accordance with 4.3.
4. Pickling and Descaling
This guide is under the jurisdiction ofASTM Committee B10 on Reactive and
Refractory Metals and Alloys and is the direct responsibility of Subcommittee
4.1 Recommendedposttreatmentofshotorabrasiveblasted
B10.01 on Titanium.
titanium surfaces may include acid pickling as described in
Current edition approved March 15, 1991. Published May 1991. Originally
published as B600 – 74. Last previous edition B600 – 74 (1985). DOI: 10.1520/ 4.3.2,toensurecompleteremovalofmetalliciron,oxide,scale,
B0600-91R02E01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
´1
B600–91 (2002)
andothersurfacecontaminants.Iftheproductistobechemical 4.3.1 After salt bath conditioning and water rinse, the
milled for the removal of the oxygen-contaminated layer, salt titanium or titanium alloy may be immersed in a sulfuric acid
bath conditioning may be required to avoid selectively etched solution to remove the converted scale product. It is recom-
surfaces if configuration interferes with uniform blasting. mended that the acid solution be maintained at 150°F (66°C)
and a concentration of 10 to 40 volume % of sulfuric acid
4.2 Scale and lubricant residues developed on mill, foundry,
forged, or fabricated titanium products usually require condi- (95 % solution by weight). Final brightening may be accom-
plished by a short immersion in the acid solution of 4.3.2.
tioning by one of the following commercial methods prior to
final pickling as described in 4.3.2 to produce a completely 4.3.2 Material that has been mechanically abraded in accor-
dance with 3.1 or chemically conditioned in accordance with
scale-free surface.
4.2.1, 4.2.2,or 4.2.3 may be finish cleaned by immersion in an
4.2.1 Proprietary solutions of caustic-based compounds in
acid solution composed of 10 to 30 volume % (150 to 450 g/L)
tap water in accordance with the manufacturer’s recommenda-
of nitric acid (70 %) and 1 to 3 volume % (12 to 36 g/L) of
tion.
hydrofluoric acid (60 %) at 120°F (49°C), maintaining a ratio
4.2.2 Molten alkaline-based salt baths operating at 750 to
of 10 parts nitric acid to 1 part hydrofluoric acid.
850°F (399 to 454°C) in accordance with prescribed proce-
dures.
NOTE 4—Hot-formed or heat-treated titanium fabrications or assem-
4.2.3 Molten alkaline-based salt baths operating at 400°F
blies that have a mixed surface contamination consisting of graphite or
molybdenum disulfi
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.