ASTM G116-99(2004)
(Practice)Standard Practice for Conducting Wire-on-Bolt Test for Atmospheric Galvanic Corrosion
Standard Practice for Conducting Wire-on-Bolt Test for Atmospheric Galvanic Corrosion
SIGNIFICANCE AND USE
The small size of the wire compared to the short galvanic interaction distance in atmospheric exposures gives a large cathode-to-anode area ratio which accelerates the galvanic attack. The area between the wire and the threads creates a long, tight crevice, also accelerating the corrosion. For these reasons, this practice, with a typical exposure period of 90 days, is the most rapid atmospheric galvanic corrosion test, particularly compared to Test Method G 104. The short duration of this test means that seasonal atmospheric variability can be evaluated. (If average performance over a 1-year period is desired, several staggered exposures are required with this technique.) Reproducibility of this practice is somewhat better than other atmospheric galvanic corrosion tests.
The major disadvantage of this test is that the anode material must be available in wire form and the cathodic material must be available in the form of a threaded rod. This should be compared to Test Method G 104 where plate or sheet material is used exclusively.
An additional limitation is that the more anodic material of the pair must be known beforehand (from information such as in Guide G 82) or assemblies must be made with the material combinations reversed.
The morphology of the corrosion attack or its effect on mechanical properties of the base materials cannot be assessed by this practice. Test Method G 104 is preferable for this purpose.
This test has been used under the names CLIMAT and ATCORR to determine atmospheric corrosivity by exposing identical specimens made from 1100 aluminum (UNS A91100) wire wrapped around threaded rods of nylon, 1010 mild steel (UNS G10100 or G10080), and CA110 copper (UNS C11000). Atmospheric corrosivity is a function of the material that is corroding, however. The relative corrosivity of atmospheres could be quite different if a different combination of materials is chosen.
SCOPE
1.1 This practice covers the evaluation of atmospheric galvanic corrosion of any anodic material that can be made into a wire when in contact with a cathodic material that can be made into a threaded rod.
1.2 When certain materials are used for the anode and cathode, this practice has been used to rate the corrosivity of atmospheres.
1.3 The wire-on-bolt test was first described in 1955 (1), and has since been used extensively with standard materials to determine corrosivity of atmospheres under the names CLIMAT Test (CLassify Industrial and Marine ATmospheres) (2-5) and ATCORR (ATmospheric CORRosivity) (6-9).
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.
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Designation:G116–99 (Reapproved 2004)
Standard Practice for
Conducting Wire-on-Bolt Test for Atmospheric Galvanic
Corrosion
This standard is issued under the fixed designation G116; 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 for Predicting Galvanic Corrosion Performance
G84 Practice for Measurement of Time-of-Wetness on Sur-
1.1 This practice covers the evaluation of atmospheric
faces Exposed to Wetting Conditions as in Atmospheric
galvaniccorrosionofanyanodicmaterialthatcanbemadeinto
Corrosion Testing
a wire when in contact with a cathodic material that can be
G91 Practice for Monitoring Atmospheric SO Using the
made into a threaded rod.
Sulfation Plate Technique
1.2 When certain materials are used for the anode and
G92 Practice for Characterization ofAtmosphericTest Sites
cathode, this practice has been used to rate the corrosivity of
G104 Test Method for Assessing Galvanic Corrosion
atmospheres.
Caused by the Atmosphere
1.3 The wire-on-bolt test was first described in 1955 (1),
and has since been used extensively with standard materials to
3. Terminology
determine corrosivity of atmospheres under the names CLI-
3.1 For definitions of terms used in this practice, refer to
MATTest(CLassifyIndustrialandMarineATmospheres)(2-5)
TerminologyG15.Forconventionsrelatedtothismethod,refer
and ATCORR (ATmospheric CORRosivity) (6-9).
to Practice G3.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Summary of Practice
responsibility of the user of this standard to establish appro-
4.1 The practice consists of wrapping a wire of the anode
priate safety and health practices and determine the applica-
material around the threads of a bolt or threaded rod of the
bility of regulatory limitations prior to use.
cathode material, exposing the assembly to atmosphere, and
determining mass loss of the anode wire after exposure.
2. Referenced Documents
Reference specimens of the anode wire on a threaded, non-
2.1 ASTM Standards:
conductive, non-porous rod are used to separate general and
G1 Practice for Preparing, Cleaning, and Evaluating Corro-
crevice corrosion effects from galvanic corrosion effects.
sion Test Specimens
G3 Practice for ConventionsApplicable to Electrochemical
5. Significance and Use
Measurements in Corrosion Testing
5.1 The small size of the wire compared to the short
G15 Terminology Relating to Corrosion and Corrosion
galvanic interaction distance in atmospheric exposures gives a
Testing
large cathode-to-anode area ratio which accelerates the gal-
G16 Guide forApplying Statistics toAnalysis of Corrosion
vanic attack.The area between the wire and the threads creates
Data
a long, tight crevice, also accelerating the corrosion. For these
G50 Practice for Conducting Atmospheric Corrosion Tests
reasons, this practice, with a typical exposure period of 90
on Metals
days, is the most rapid atmospheric galvanic corrosion test,
G82 Guide for Development and Use of a Galvanic Series
particularlycomparedtoTestMethodG104.Theshortduration
of this test means that seasonal atmospheric variability can be
evaluated. (If average performance over a 1-year period is
This practice is under the jurisdiction of ASTM Committee G01 on Corrosion
of Metals and is the direct responsibility of Subcommittee G01.04 on Atmospheric
desired, several staggered exposures are required with this
Corrosion.
technique.) Reproducibility of this practice is somewhat better
Current edition approved Nov 1, 2004. Published November 2004. Originally
than other atmospheric galvanic corrosion tests.
approved in 1993. Last previous edition approved in 1999 as G116 – 99. DOI:
10.1520/G0116-99R04. 5.2 The major disadvantage of this test is that the anode
The boldface numbers in parentheses refer to the list of references at the end of
material must be available in wire form and the cathodic
this standard.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Withdrawn.
the ASTM website. Nylon 66 has been found suitable for this purpose.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
G116–99 (2004)
material must be available in the form of a threaded rod. This
should be compared to Test Method G104 where plate or sheet
material is used exclusively.
5.3 An additional limitation is that the more anodic material
of the pair must be known beforehand (from information such
asinGuideG82)orassembliesmustbemadewiththematerial
combinations reversed.
5.4 The morphology of the corrosion attack or its effect on
mechanical properties of the base materials cannot be assessed
by this practice. Test Method G104 is preferable for this
purpose.
5.5 This test has been used under the names CLIMAT and
ATCORR to determine atmospheric corrosivity by exposing
identicalspecimensmadefrom1100aluminum(UNSA91100)
wire wrapped around threaded rods of nylon, 1010 mild steel
(UNS G10100 or G10080), and CA110 copper (UNS C11000).
Atmospheric corrosivity is a function of the material that is
corroding, however. The relative corrosivity of atmospheres
could be quite different if a different combination of materials
is chosen.
6. Interferences
6.1 The manufacturing process used to make the wire and
rod may affect their corrosion potentials and polarization
behavior. Material in these forms may not behave galvanically
the same as material in the form of interest, such as fasteners
in sheet roofing for example.Although unlikely, this may even
FIG. 1 Components for Making Wire-on-Bolt Exposure
lead to a situation where reversing the materials may also Assemblies
reverse their anode-cathode relationship, resulting in attack
during service of a material which was resistant during testing
7.2.4 Wrap the wire tightly around the rod so that it lies
as a wire.
inside the threads using a jig such as that shown in Fig. 2. This
7. Procedure jigisusedtokeepconstanttensiononthewirewhileitisbeing
wound. While using this jig, wear clean cotton gloves to
7.1 Components:
prevent contamination of the surfaces of the wire or rod. If it is
7.1.1 The components used to construct the specimen as-
felt that the wire tension is not critical for the particular
semblies for this test are shown in Fig. 1.
application being tested, replace the use of the jig with
7.1.2 Prepare a 1-m length of 0.875 + 0.002-mm diameter
hand-winding.
wire of the anode material for each assembly. Other diameters
may be used, however, the diameter of the wire may affect the
test results, so that tests may only be compared if they use wire
ofsimilardiameters.Inselectingmaterialforthewire,consider
the cold work and heat treatment of a wire may be significantly
different than for the component that the exposure is modeling.
7.1.3 Make the cathode material into M12 3 1.75 ( ⁄2 -13
-UNC threaded rods or bolts, 100-mm long. Either metric or
Englishthreadsmaybeused,butresultsmayonlybecompared
between assemblies with similar thread types.
7.2 Making the Assemblies:
7.2.1 Thoroughly clean and degrease all parts before assem-
bly in accordance with Practice G1.
7.2.2 Determine the mass of the wire to the nearest 0.0001
g.
7.2.3 Secure one end of the wire to a threaded rod using
small screws and nuts of the rod material, if possible, or of
nylon, stainless steel insulated with nylon, acetal resin, or
TFE-fluorocarbon. Plastic washers are usually used under the
headsofthescrews.Thewiremayinsteadbesecuredtotherod
by means of a tight O-ring wrapped around the threaded rod
FIG. 2 Constant Tension Coil Winder for Wrapping Wire or
and the wire together. Threaded Rods
G116–99 (2004)
7.2.5 Wind the wire until it is in contact with roughly an
axial distance of 50 mm of threaded rod.
7.2.6 Secure the free wire end to the rod by means of small
screws and nuts made of the rod material, if possible, or of
nylon, stainless steel insulated with nylon, acetal resin, or
TFE-fluorocarbon. Plastic washers are usually u
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