1、Designation: G116 99 (Reapproved 2010)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 MarineATmospheres) (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 includ
5、ed 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 CorrosionTesting4G16 Guide for Applying Stat
7、istics 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 Conditions as in Atmos
8、phericCorrosion TestingG91 Practice for Monitoring Atmospheric SO2Using theSulfation Plate TechniqueG92 Practice for Characterization ofAtmospheric Test SitesG104 Test Method for Assessing Galvanic CorrosionCaused by the Atmosphere43. Terminology3.1 For definitions of terms used in this practice, re
9、fer 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, exposing the assembly to atmosphere, anddetermining mass los
10、s 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 small size of the wire compared to the shortgalvanic interac
11、tion 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, this practice, with a typical exposure period of 90days,
12、is the most rapid atmospheric galvanic corrosion test,particularly 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 are required with thistechn
13、ique.) Reproducibility of this practice is somewhat betterthan other atmospheric galvanic corrosion tests.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 May
14、1, 2010. Published May 2010. Originallyapproved in 1993. Last previous edition approved in 2004 as G11699 (2004). DOI:10.1520/G0116-99R10.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards, visit the ASTM website, www.astm.o
15、rg, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 1
16、00 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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 rod. Thisshould be compared to Test Method G104 whe
17、re 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.5.4 The morphology of the corrosion attack or its e
18、ffect 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 exposingidentical specimens made from 1100 aluminum (UNSA91100)w
19、ire 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 different if a different combination of materialsis c
20、hosen.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 fastenersin sheet roofing for example. Although un
21、likely, 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 components used to construct the specimen as-sembl
22、ies 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 only be compared if they use wireof similar diameters
23、. 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 3 1.75 (12-13-UNC threaded rods or bolts, 100-mm long. Either metric orEnglish threads
24、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 the nearest0.0001 g.7.2.3 Secure one end of the wi
25、re 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 secured to the rodby means of a tight O-ring wr
26、apped 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 using this jig, wear clean cotton gloves toprev
27、ent contamination of the surfaces of the wire or rod. If it isFIG. 1 Components for Making Wire-on-Bolt ExposureAssembliesFIG. 2 Constant Tension Coil Winder for Wrapping Wire orThreaded RodsG116 99 (2010)2felt that the wire tension is not critical for the particularapplication being tested, replace
28、 the use of the jig withhand-winding.7.2.5 Wind the wire until it is in contact with roughly anaxial 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, a
29、cetal resin, orTFE-fluorocarbon. Plastic washers are usually used under theheads of screws. The wire may instead be secured to the rod bymeans of a tight O-ring wrapped around the threaded rod andthe wire together.7.2.7 Clip off the excess wire, if any, and determine themass of the removed piece.7.2
30、.8 Prepare a minimum 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 plasti
31、c plates. Fig. 3 shows 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
32、.8. Measurements8.1 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
33、dropped out of the 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 Interpret
34、ation of Results9.1 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 r
35、ods andthose on the 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 ma
36、ss of the wire removedas 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 3 original wire mass/initial mas
37、sThis mass loss should 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 %!5te
38、st mass loss/m 2 reference mass loss/mreference mass loss/m3 1009.5 The average and standard deviation should 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 % confidenc
39、e level.If the difference is not significant, the galvanic effect should bereported as zero. Statistical analyses 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 (negativegalva
40、nic effect) as determined by the t test, then it is likely thatthe wrong material was assumed to be the anode at the outset,FIG. 3 Schematic Completed Wire-on-Bolt Assemblies Mountedfor ExposureFIG. 4 Completed WireonBolt Assemblies Ready for ExposureG116 99 (2010)3and another exposure with the role
41、s 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, longer or shorter exposuredurations may be needed to
42、 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 masses,10.1.4 Exposure site location,10.1.5 Any
43、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 and Bias11.1 Intralaboratory Variability (Repeat
44、ability)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 variationranged from 0.059 to 0.266 %. Typical variab
45、ility 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)Typicalvariability between results of identical
46、 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; architectural materials; ATCORR test; at-mospheric corros
47、ion; 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 Bolt and Wire Test,” Symposiumon Atmospheric Corr
48、osion 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.,“ARapid Method for Determining theCorrosivity of the Atmosphere at Any Locati
49、on,” 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 Marine Atmo-spheres,” Paper No. 71 CP 172-PWR, presented at the IEEE WinterPower Meeting, NY, JanFeb 1971.(6) King, G. A., and Gibbs, P., “Corrosivity Mapping Around a Point
