1、Designation: G116 99 (Reapproved 2015)Standard Practice forConducting Wire-on-Bolt Test for Atmospheric GalvanicCorrosion1This standard is issued under the fixed designation G116; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the evaluation of atmosphericgalvanic corrosion of any anodic material that can be made
3、intoa wire when in contact with a cathodic material that can bemade into a threaded rod.1.2 When certain materials are used for the anode andcathode, this practice has been used to rate the corrosivity ofatmospheres.1.3 The wire-on-bolt test was first described in 1955 (1),2and has since been used e
4、xtensively with standard materials todetermine corrosivity of atmospheres under the names CLI-MAT Test (CLassify Industrial and Marine ATmospheres)(2-5) and ATCORR (ATmospheric CORRosivity) (6-9).1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are inclu
5、ded in thisstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to
6、 use.2. Referenced Documents2.1 ASTM Standards:3G1 Practice for Preparing, Cleaning, and Evaluating Corro-sion Test SpecimensG3 Practice for Conventions Applicable to ElectrochemicalMeasurements in Corrosion TestingG15 Terminology Relating to Corrosion and Corrosion Test-ing (Withdrawn 2010)4G16 Gui
7、de for Applying Statistics to Analysis of CorrosionDataG50 Practice for Conducting Atmospheric Corrosion Testson MetalsG82 Guide for Development and Use of a Galvanic Seriesfor Predicting Galvanic Corrosion PerformanceG84 Practice for Measurement of Time-of-Wetness on Sur-faces Exposed to Wetting Co
8、nditions as in AtmosphericCorrosion TestingG91 Practice for Monitoring Atmospheric SO2DepositionRate for Atmospheric Corrosivity EvaluationG92 Practice for Characterization of Atmospheric Test SitesG104 Test Method forAssessing Galvanic Corrosion Causedby the Atmosphere (Withdrawn 1998)43. Terminolo
9、gy3.1 For definitions of terms used in this practice, refer toTerminology G15. For conventions related to this method, referto Practice G3.4. Summary of Practice4.1 The practice consists of wrapping a wire of the anodematerial around the threads of a bolt or threaded rod of thecathode material, expo
10、sing the assembly to atmosphere, anddetermining mass loss of the anode wire after exposure.Reference specimens of the anode wire on a threaded, non-conductive, non-porous rod are used to separate general andcrevice corrosion effects from galvanic corrosion effects.5. Significance and Use5.1 The smal
11、l size of the wire compared to the shortgalvanic interaction distance in atmospheric exposures gives alarge cathode-to-anode area ratio which accelerates the gal-vanic attack. The area between the wire and the threads createsa long, tight crevice, also accelerating the corrosion. For thesereasons, t
12、his practice, with a typical exposure period of 90days, is the most rapid atmospheric galvanic corrosion test,1This practice is under the jurisdiction of ASTM Committee G01 on Corrosionof Metals and is the direct responsibility of Subcommittee G01.04 on AtmosphericCorrosion.Current edition approved
13、Nov. 1, 2015. Published December 2015. Originallyapproved in 1993. Last previous edition approved in 2010 as G11699 (2010). DOI:10.1520/G0116-99R15.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards, visit the ASTM website,
14、www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100
15、 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1particularly compared to Test Method G104. The short durationof this test means that seasonal atmospheric variability can beevaluated. (If average performance over a 1-year period isdesired, several staggered exposures
16、are required with thistechnique.) Reproducibility of this practice is somewhat betterthan other atmospheric galvanic corrosion tests.5.2 The major disadvantage of this test is that the anodematerial must be available in wire form and the cathodicmaterial must be available in the form of a threaded r
17、od. Thisshould be compared to Test Method G104 where plate or sheetmaterial is used exclusively.5.3 An additional limitation is that the more anodic materialof the pair must be known beforehand (from information suchas in Guide G82) or assemblies must be made with the materialcombinations reversed.5
18、.4 The morphology of the corrosion attack or its effect onmechanical properties of the base materials cannot be assessedby this practice. Test Method G104 is preferable for thispurpose.5.5 This test has been used under the names CLIMAT andATCORR to determine atmospheric corrosivity by exposingidenti
19、cal specimens made from 1100 aluminum (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 iscorroding, however. The relative corrosivity of atmospherescould be quite dif
20、ferent if a different combination of materialsis chosen.6. Interferences6.1 The manufacturing process used to make the wire androd may affect their corrosion potentials and polarizationbehavior. Material in these forms may not behave galvanicallythe same as material in the form of interest, such as
21、fastenersin sheet roofing for example. Although unlikely, this may evenlead to a situation where reversing the materials may alsoreverse their anode-cathode relationship, resulting in attackduring service of a material which was resistant during testingas a wire.7. Procedure7.1 Components:7.1.1 The
22、components used to construct the specimen as-semblies for this test are shown in Fig. 1.7.1.2 Prepare a 1-m length of 0.875 + 0.002-mm diameterwire of the anode material for each assembly. Other diametersmay be used, however, the diameter of the wire may affect thetest results, so that tests may onl
23、y be compared if they use wireof similar diameters. In selecting material for the wire, considerthe cold work and heat treatment of a wire may be significantlydifferent than for the component that the exposure is modeling.7.1.3 Make the cathode material into M12 1.75 (12-13-UNC threaded rods or bolt
24、s, 100-mm long. Either metric orEnglish threads may be used, but results may only be comparedbetween 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 th
25、e nearest0.0001 g.7.2.3 Secure one end of the wire to a threaded rod usingsmall screws and nuts of the rod material, if possible, or ofnylon, stainless steel insulated with nylon, acetal resin, orTFE-fluorocarbon. Plastic washers are usually used under theheads of the screws. The wire may instead be
26、 secured to the rodby means of a tight O-ring wrapped around the threaded rodand the wire together.7.2.4 Wrap the wire tightly around the rod so that it liesinside the threads using a jig such as that shown in Fig. 2. Thisjig is used to keep constant tension on the wire while it is beingwound. While
27、 using this jig, wear clean cotton gloves toprevent contamination of the surfaces of the wire or rod. If it isfelt that the wire tension is not critical for the particularapplication being tested, replace the use of the jig withhand-winding.7.2.5 Wind the wire until it is in contact with roughly ana
28、xial distance of 50 mm of threaded rod.7.2.6 Secure the free wire end to the rod by means of smallscrews and nuts made of the rod material, if possible, or ofnylon, stainless steel insulated with nylon, acetal resin, orTFE-fluorocarbon. Plastic washers are usually used under theheads of screws. The
29、wire may instead be secured to the rod bymeans of a tight O-ring wrapped around the threaded rod andthe wire together.FIG. 1 Components for Making Wire-on-Bolt Exposure Assem-bliesG116 99 (2015)27.2.7 Clip off the excess wire, if any, and determine themass of the removed piece.7.2.8 Prepare a minimu
30、m of 3 test assemblies using rods ofthe cathode material and 3 reference assemblies using anonconductive (nylon) rod for each material combination to bestudied.7.3 Mounting and Exposure:7.3.1 Hold the assemblies vertically by screwing the rodends furthest from the wire into plastic plates. Fig. 3 sh
31、ows aschematic of a completed assembly, and Fig. 4 is a photographof an actual completed assembly just before exposure.7.3.2 Mount the plates horizontally on racks such as de-scribed in Practice G50.7.3.3 Expose the assemblies for roughly 90 days in theatmospheric site of interest.8. Measurements8.1
32、 It is desirable to characterize or monitor the atmosphericsite during test by using one or more of the following PracticesG84, G91,orG92.8.2 After exposure visually inspect the specimens and notethe condition of the wires. If any sections of wire aresufficiently corroded to have dropped out of the
33、assembly, thenthe test is invalid and a shorter duration of exposure should bechosen for a retest.8.3 Remove and clean the specimens according to theprocedures specified in Practice G1 for the material involved.8.4 Determine the final mass of the wires.9. Calculation and Interpretation of Results9.1
34、 The wires exposed on the nonconductive rods are usedfor reference since they will have experienced no galvaniceffects, while the test wires on the cathode rods will haveexperienced additional galvanic action. It is the differencebetween the mass loss of the wires on the cathode rods andthose on the
35、 plastic rods which is an indication of galvaniccorrosion.9.2 Since the length of wire actually exposed will be slightlydifferent for each assembly, the length differences must becorrected for. The mass loss of the wire is corrected to that fora standard 1-m length by using the mass of the wire remo
36、vedas in 9.3.9.3 Calculate the mass loss per unit length of wire for eachtest and reference assembly as follows:initial mass 5 original wire mass 2 excess wire mass removedmass loss 5 initial mass 2 final mass after exposure!mass loss/m 5 mass loss 3original wire mass/initial massThis mass loss shou
37、ld be normalized to a 90-day period bydividing by the actual number of days of exposure andmultiplying by 90.9.4 Galvanic effects are calculated as the percent differencesin the mass loss per metre between wires in the test andreference assemblies as follows:galvanic effect %!5test mass loss/m 2 ref
38、erence mass loss/mreference mass loss/m3100FIG. 2 Constant Tension Coil Winder for Wrapping Wire orThreaded RodsFIG. 3 Schematic Completed Wire-on-Bolt Assemblies Mountedfor ExposureFIG. 4 Completed WireonBolt Assemblies Ready for ExposureG116 99 (2015)39.5 The average and standard deviation should
39、be calculatedfor mass loss per unit length of test specimens and referencespecimens. The Students t test should be done to determine ifthese mass losses are significant at the 95 % confidence level.If the difference is not significant, the galvanic effect should bereported as zero. Statistical analy
40、ses of the results should bedone in accordance with Guide G16.9.6 If it is found after exposure that the wire on the cathoderod lost significantly less mass than the reference (negativegalvanic effect) as determined by the t test, then it is likely thatthe wrong material was assumed to be the anode
41、at the outset,and another exposure with the roles of the two materialsreversed must be conducted. If the relationship between thetwo materials is in doubt and time is limited, dual exposuresshould be conducted.9.7 Depending on the material combinations selected andcorrosivity of the atmosphere, long
42、er or shorter exposuredurations may be needed to get measurable mass loss or toprevent loss of the wire during exposure.10. Report10.1 Report the following information:10.1.1 Anode material and form, including wire diameter,10.1.2 Cathode material and form, including thread typeused,10.1.3 All wire
43、masses,10.1.4 Exposure site location,10.1.5 Any atmospheric conditions monitored,10.1.6 Exposure duration,10.1.7 Results and calculations,10.1.8 Any unusual occurrences during the test,10.1.9 Any unusual post exposure appearance, and10.1.10 Statistical analyses of results if performed.11. Precision
44、and Bias11.1 Intralaboratory Variability (Repeatability)Standarddeviation of the % mass loss of 6 specimens of magnesiumwire on each of 14 different bolt materials ranged from 0.26 to1.81 in a 100-day exposure in a New York industrial atmo-sphere (1). For these same samples, the coefficient of varia
45、tionranged from 0.059 to 0.266 %. Typical variability betweentriplicate specimens made from the CLIMAT materials is beingdeveloped in an ongoing round-robin withinASTM CommitteeG01 on Corrosion of Metals, Subcommittee G01.04 on Atmo-spheric Corrosion.11.2 Interlaboratory Variability (Reproducibility
46、)Typicalvariability between results of identical specimens prepared bydifferent laboratories and exposed at the same location is beingdeveloped in an ongoing round-robin withinASTM CommitteeG01 on Corrosion of Metals, Subcommittee G01.04 on Atmo-spheric Corrosion.12. Keywords12.1 aluminum; architect
47、ural materials; ATCORR test; at-mospheric corrosion; atmospheric corrosivity; bolts; CLIMATtest; copper; corrosion; corrosion test; corrosivity; galvaniccorrosion; rod; wire; wire-on-bolt testREFERENCES(1) Compton, K. G., and Mendizza, A., “Galvanic Couple CorrosionStudies by Means of the Threaded B
48、olt and Wire Test,” Symposium onAtmospheric Corrosion of Non-Ferrous Metals, STP 175, ASTM,1955, pp. 116125.(2) Compton, K. G., Mendizza, A., and Bradley, W. W., “AtmosphericGalvanic Couple Corrosion,” Corrosion, Vol 11, 1955, p. 383t.(3) Doyle, D. P., and Godard, H. G.,“ A Rapid Method for Determin
49、ingthe Corrosivity of theAtmosphere atAny Location,” Nature, Vol 200,No. 4912, December 1963, pp. 11671168.(4) Doyle, D. P., and Godard, H. G., “Rapid Determination of Corrosivityof an Atmosphere to Aluminum,” Proceedings of the Third Interna-tional Congress on Metallic Corrosion, Vol 4, MIR Publishers,Moscow, USSR,1969, pp. 429437.(5) Doyle, D. P., and Wright, T. E., “A Rapid Method for PredictingAdequate Service Lives for Overhead Conductors in MarineAtmospheres,” Paper No. 71 CP 172-PWR, presented at the IEEEWinter Power Meeting, NY, JanFeb 1971.(6) King, G. A., an
