ASTM G66-99(2013)
(Test Method)Standard Test Method for Visual Assessment of Exfoliation Corrosion Susceptibility of 5XXX Series Aluminum Alloys (ASSET Test)
Standard Test Method for Visual Assessment of Exfoliation Corrosion Susceptibility of 5XXX Series Aluminum Alloys (ASSET Test)
SIGNIFICANCE AND USE
5.1 This test method provides a reliable prediction of the exfoliation corrosion behavior of Al-Mg alloys in marine environments.5,6,7 The test is useful for alloy development studies and quality control of mill products such as sheet and plate.
SCOPE
1.1 This test method covers a procedure for continuous immersion exfoliation corrosion testing of 5XXX series aluminum-magnesium alloys containing 2.0 % or more magnesium.
1.2 This test method applies only to wrought products.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
Designation: G66 − 99 (Reapproved 2013)
Standard Test Method for
Visual Assessment of Exfoliation Corrosion Susceptibility of
5XXX Series Aluminum Alloys (ASSET Test)
ThisstandardisissuedunderthefixeddesignationG66;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope metal away from the body of the material, giving rise to a
layered appearance (see Terminology G15).
1.1 This test method covers a procedure for continuous
immersion exfoliation corrosion testing of 5XXX series
4. Summary of Test Method
aluminum-magnesium alloys containing 2.0 % or more mag-
4.1 Specimens are immersed for 24 h at 65 6 1°C (150 6
nesium.
2°F) in a solution containing ammonium chloride, ammonium
1.2 This test method applies only to wrought products.
nitrate, ammonium tartrate, and hydrogen peroxide. The sus-
1.3 The values stated in SI units are to be regarded as the ceptibility to exfoliation is determined by visual examination
standard. The values given in parentheses are for information using performance ratings established by reference to standard
photographs.
only.
1.4 This standard does not purport to address all of the
5. Significance and Use
safety concerns, if any, associated with its use. It is the
5.1 This test method provides a reliable prediction of the
responsibility of the user of this standard to establish appro-
exfoliation corrosion behavior of Al-Mg alloys in marine
priate safety and health practices and determine the applica-
5,6,7
environments. The test is useful for alloy development
bility of regulatory limitations prior to use.
studies and quality control of mill products such as sheet and
2. Referenced Documents plate.
2.1 ASTM Standards:
6. Apparatus
D1193 Specification for Reagent Water
6.1 Any suitable glass or plastic container can be used to
G15 Terminology Relating to Corrosion and Corrosion Test-
3 contain the solution and specimens during the test period.
ing (Withdrawn 2010)
Depending upon the shape and size of the specimens, rods or
2.2 ASTM Adjuncts:
4 racks of glass, plastic, or other inert substance shall be used to
ASSET Tested Specimens (Glossy Prints)
support the specimens above the bottom of the container. The
container should be fitted with a removable cover to reduce
3. Terminology
evaporation.
3.1 Definitions:
3.1.1 exfoliation—corrosion that proceeds laterally from the
7. Reagents
sites of initiation along planes parallel to the surface, generally
7.1 Purity of Reagents—Reagent grade chemicals shall be
at grain boundaries, forming corrosion products that force
used in all tests.
7.2 Purity of Water—Distilled or deionized water conform-
This test method is under the jurisdiction of ASTM Committee G01 on
ing to Specification D1193. Type IV shall be used to prepare
Corrosion of Metals and is the direct responsibility of Subcommittee G01.05 on
the test solution except chloride ion sodium limits can be
Laboratory Corrosion Tests. This method was developed by a joint task group with
The Aluminum Assoc., Inc.
disregarded.
CurrenteditionapprovedMay1,2013.PublishedJuly2013.Originallyapproved
in 1980. Last previous edition approved in 2005 as G66 – 99 (2005). DOI:
10.1520/G0066-99R13. AluminumAssociation Technical Report T1,“ Exfoliation Corrosion Testing of
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Aluminum Alloys 5086 and 5456”.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Sprowls, D. O., Walsh, J. D. and Shumaker, M. B., “Simplified Exfoliation
Standards volume information, refer to the standard’s Document Summary page on TestingofAluminumAlloys”, Localized Corrosion—Cause of Metal Failure, ASTM
the ASTM website. STP 516, ASTM, 1972, pp 38–65.
3 7
The last approved version of this historical standard is referenced on Summerson T. J., Interim Report, Aluminum Association Task Group on
www.astm.org. Exfoliation and Stress Corrosion Cracking of Aluminum Alloys for Boat Stock;
Available from ASTM International Headquarters. Order Adjunct No. ProceedingsTri-Service Corrosion Military Equipment Conference, October 29–31,
ADJG0066. Original adjunct produced in 1987. 1974; Technical Report AFML-TR-75-42, Vol. II, p. 193–221, February 1, 1975.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G66 − 99 (2013)
8. Test Solution by weight sodium hydroxide solution at 80°C (176°F), rinse in
water, desmut 30 s in concentrated nitric acid at room
8.1 Preparation of Test Solution:
temperature, rinse with distilled or deionized water, air dry.
8.1.1 The test solution shall have the following composi-
tion:
NOTE 2—If specimens are not to be immersed in the test solution
immediately, they should be stored in a desiccator maintained at less than
NH Cl (1.0 M)
1 % relative humidity (use fresh desiccant such as activated alumina or
NH NO (0.25 M)
4 3
anhydrous calcium sulfate).
(NH ) C H O (0.01 M)
4 2 4 4 6
H O (0.09 M)
2 2
12.2 Use fresh solution at the start of each test.
8.1.2 Dissolve 53.5 g ammonium chloride (NH Cl), 20.0 g
12.3 Immerse the specimens vertically with the top edge of
ammonium nitrate (NH NO ), 1.8 g ammonium tartrate
4 3
the specimens at least 25 mm (1 in.) below the surface of the
((NH ) C H O ), and 10 mL of 30 % stock solution hydrogen
4 2 4 4 6
solution and the bottom edge at least 25 mm above the bottom
peroxide (H O ) in a small amount of water. After dissolving,
2 2
of the container.
mix the components together thoroughly and adjust the final
12.4 Immerse the specimens in the test solution continu-
dilution to 1 L.
ously for 24 h.
NOTE 1—If a stock solution of the above chemicals is to be stored, the
hydrogen peroxide should not be added until the solution is heated for the 12.5 Rinse the specimens gently in running tap water
test.
immediately after removal from the solution, then soak in
concentrated nitric acid at room temperature until they appear
8.2 The solution will have a typical pH of 5.2 to 5.4.
clean, again rinse in water, and air dry.
8.3 The solution shall be used in sufficient quantity to
12.5.1 Air-blast drying is to be avoided in order to prevent
provide a volume-to-exposed specimen surface area ratio of at
mechanical removal of exfoliated metal.
2 2
least 100 L/m (65 mL/in. ).
13. Rating of Specimens
8.4 The temperature of the solution shall be maintained at
65 6 1°C (150 6 2°F).
13.1 The following codes and classifications shall be used
for reporting the visual appearance of corroded specimens.
9. Sampling
Code Classification
N No appreciable attack
9.1 The procedure for sampling mill products is covered in
P Pitting
product specifications, or otherwise, and is considered outside
E Exfoliation
the scope of this standard.
13.2 Descriptions of the various classifications, which are
illu
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