1、Designation: G198 17Standard Test Method forDetermining the Relative Corrosion Performance of DrivenFasteners in Contact with Treated Wood1This standard is issued under the fixed designation G198; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、 of revision, the 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. Scope*1.1 This test method covers and focuses on the corrosionresistance of metal, metal-coated, and
3、nonmetallic-coatedsmooth and deformed shank driven fasteners in contact withtreated wood in exterior or high moisture exposure applicationsusing comparative tests with control fastener specimens ofstandardized benchmarks. This test method may be used forpreservative-treated wood.1.2 This test method
4、 describes the apparatus, procedure, andconditions required to maintain test environments for theCyclic Fog Test and the Steady State Moisture Test.1.3 This test method describes the types of test samples, listsexposure periods, and gives guidance on interpretation ofresults.1.4 Until experience is
5、gained comparing laboratory-to-laboratory results with this test method, comparisons offasteners, coatings, materials, or preservatives shall be madeonly within the results of the same test.1.5 The values stated in SI units are to be regarded asstandard. The values in parentheses are for information
6、 only.1.6 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 use.1.7 This
7、international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (T
8、BT) Committee.2. Referenced Documents2.1 ASTM Standards:2A90/A90M Test Method for Weight Mass of Coating onIron and Steel Articles with Zinc or Zinc-Alloy CoatingsA153/A153M Specification for Zinc Coating (Hot-Dip) onIron and Steel HardwareB117 Practice for Operating Salt Spray (Fog) ApparatusB487 T
9、est Method for Measurement of Metal and OxideCoating Thickness by Microscopical Examination ofCross SectionB499 Test Method for Measurement of Coating Thicknessesby the Magnetic Method: Nonmagnetic Coatings onMagnetic Basis MetalsB504 Test Method for Measurement of Thickness of Metal-lic Coatings by
10、 the Coulometric MethodD610 Practice for Evaluating Degree of Rusting on PaintedSteel SurfacesD1165 Nomenclature of Commercial Hardwoods and Soft-woodsD1193 Specification for Reagent WaterD4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Based MaterialsD4444 Test Method fo
11、r Laboratory Standardization andCalibration of Hand-Held Moisture MetersE376 Practice for Measuring Coating Thickness byMagnetic-Field or Eddy-Current (Electromagnetic) Test-ing MethodsG1 Practice for Preparing, Cleaning, and Evaluating Corro-sion Test SpecimensG60 Practice for Conducting Cyclic Hum
12、idity ExposuresG85 Practice for Modified Salt Spray (Fog) TestingG193 Terminology and Acronyms Relating to Corrosion2.2 American Wood Protection Association:3U1-09 Use Category System: Use Specification for TreatedWood1This test method is under the jurisdiction of ASTM Committee G01 onCorrosion of M
13、etals and is the direct responsibility of Subcommittee G01.14 onCorrosion of Metals in Construction Materials.Current edition approved May 15, 2017. Published May 2017. Originallyapproved in 2011. Last previous edition approved in 2016 as G198 11 (2016).DOI:10.1520/G019817.2For referenced ASTM stand
14、ards, visit the ASTM website, 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.3Available from American Wood Protection Association (AWPA), P.O. Box361784, Birmingham
15、, AL 35236-1784, http:/.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles
16、 on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13. Terminology3.1 DefinitionsTerminology G193 contains other termsand definition
17、s relating to corrosion and corrosion testing.Terminology D1165 contains other terms and definitions relat-ing to wood and wood testing.3.2 Definitions of Terms Specific to This Standard:3.2.1 bright, adjuncoated steel.3.2.2 fastener, nmetallic, metal-coated, or nonmetallic-coated smooth or deformed
18、 shank driven fastener.3.2.3 test sample, ncombination of fasteners installed intoa treated wood specimen.3.2.4 wood specimen, nsection of wood into which fas-teners are driven to form test samples. Specimens may betreated for testing of materials, coatings, or chemicals or maybe untreated for use a
19、s controls.3.2.4.1 DiscussionWood cross-sectional dimensions aregiven in exact numbers for SI units and nominal numbers forinch-pound units.4. Summary of Test Method4.1 This test method covers the preparation, testing andevaluation of metal, metal-coated, or nonmetallic-coatedsmooth or deformed shan
20、k driven fasteners installed in treatedwood. Control specimens tested in the same conditions shall behot-dip galvanized fasteners that are coated as described inSpecification A153/A153M or bright fasteners with no coat-ings. The fasteners are installed in the treated wood specimenbefore testing so t
21、hat the chemicals in the wood are in directcontact with the metal or coating. Test samples are then testedin Steady State Moisture Tests or Cyclic Fog Tests. For eachtype of sample, separate groups of test samples shall be testedunder either or both of the two test conditions. Procedures forconducti
22、ng tests in two environmental conditions, Steady StateMoisture Tests and Cyclic Fog Tests, are described as well asposition of the samples and measurement techniques fordetermining the degree of corrosion. Guidance is given formethods of exposure and inspection of corroded fasteners inthe two enviro
23、nmental conditions.5. Significance and Use5.1 This test method provides controlled environmentswhich are utilized to produce corrosion of metal, metal-coated,or nonmetallic-coated smooth or deformed shank driven fas-teners in contact with treated wood exposed to the given testenvironments. The test
24、method provides information that canbe used to evaluate the corrosion resistance of metal, metal-coated, or nonmetallic-coated smooth or deformed shankdriven fasteners in contact with different chemical woodtreatments.5.2 The results shall be used for comparative purposes onlyand they shall not be c
25、orrelated to exposure time in naturalenvironments.5.3 The reproducibility of results in these types of tests ishighly dependent on the type of samples tested and theevaluation criteria selected, as well as the control of theoperating variables.6. Apparatus6.1 Steady State Moisture TestThe apparatus
26、required forsteady state moisture tests shall consist of a test chamber,provisions for heating the chamber, a humidifying tower, asupply of compressed air, sample supports, and necessarymeans of control.6.1.1 There are no size or construction requirements otherthan those needed to meet the requireme
27、nts of the test method.6.1.2 A schematic diagram of a typical apparatus is shownin Practice G60, Figure 1.6.1.3 The apparatus shall be capable of providing a relativehumidity of 95 % for 24 h a day for a period of at least 120days.6.1.4 The apparatus shall be capable of providing a constanttemperatu
28、re of 32 6 2C (90 6 3F).6.2 Cyclic Fog TestThe cyclic fog test shall consist of afog chamber with a solution reservoir, a supply of suitablyconditioned compressed air, one or more atomizing nozzles,specimen supports, provisions for heating the chamber andnecessary means of controlling fog spray and
29、heating cyclesand means of purging fog with fresh air prior to heat cycles fora period of at least 120 days. The material of construction shallbe such that it will not affect the corrosiveness of the fog.Similar tests are described in Practice B117 and Practice G85with the exception that these pract
30、ices use salt solutions duringthe testing.6.2.1 Drops of solution which accumulate on the ceiling orcover of the chamber shall not be permitted to fall on thesamples being exposed and shall not be returned to thereservoir for respraying.6.2.2 Drops of solution which fall from the samples shallnot be
31、 returned to the solution reservoir for respraying.7. Reagents and Materials7.1 Water used for this test method shall conform to Type IVwater as described in Specification D1193 and shall be referredto as purified water.8. Air Supply8.1 The compressed air supply shall be free of water, grease,oil an
32、d dirt.NOTE 1The air supply may be freed from oil and dust by passing itthrough a suitable oil/water extractor (that is commercially available) tostop any oil from emerging. Many oil/water extractors have an expirationindicator; proper preventive maintenance intervals should take these intoaccount.9
33、. Sampling, Test Specimens, and Test Units9.1 Fastener Specimens:9.1.1 A minimum of 65 fasteners shall be used for completeevaluation per this test method using both test conditions onany type of sample fastener; metal, metal-coated, ornonmetallic-coated. Multiple fastener types may be tested inthe
34、same cycle of testing with one set of control fasteners.Different fastener lengths may require different wood sizes toaccommodate the length of the fasteners.9.1.2 Initial Cleaning of Metal, Metal-Coated, orNonmetallic-Coated Smooth or Deformed Shank DrivenG198 172FastenersInitial cleaning of fasten
35、er shall be done by rinsingwith purified water and drying with forced hot air, air tempera-ture shall be between 40 to 60C (104 to 140F).9.1.3 Coating MassFive randomly selected fasteners shallbe taken from the cleaned group of fasteners and shall bestripped of coating and weighed to determine the a
36、veragecoating mass. Stripping and weighing of zinc and zinc-alloyproducts shall be in accordance Test Method A90/A90M. Themass for an individual fastener shall be determined to thenearest 0.001 g (0.000032 oz). Coatings other than zinc shallbe stripped using an appropriate method to measure coatingm
37、ass of the corrosion-resistant layer(s). Coatings other thanzinc and zinc-alloys shall have their mass or coating thicknessdetermined by one of the following methods; Test MethodB487, Test Method B499, Test Method B504, or Practice E376.9.1.4 Fastener DiameterThe sample group of five randomfasteners
38、 from 9.1.3 shall be used to measure the core diameterof the fastener. The diameter shall be measured at mid-length,610 mm (60.4 in.), on the shank of each fastener and is theminimum diameter measurement at the selected cross section.For deformed shank fasteners the measurement shall be madeat a por
39、tion of the shank that has not been deformed, if such asurface is available. Portions of nail shanks with gripper marksshall also be avoided, if possible. The diameter shall bemeasured to the nearest 0.025 mm (0.001 in.) The five samplediameter measurements shall be averaged to obtain the groupfaste
40、ner diameter.9.1.5 Control Fastener GroupThere shall be a group ofhot-dip galvanized fasteners that are galvanized to Specifica-tion A153/A153M. When testing some coated fasteners, themore appropriate control fastener group will be bright fastenersrather than galvanized fasteners. Fasteners in the c
41、ontrolsamples shall be of the same nominal diameter and length asthe fasteners that are being tested and shall have similargeometry to the fasteners that are being tested.9.2 Treated Wood Specimens:9.2.1 Each treated wood specimen used in this procedureshall be weighed using a balance or scale to th
42、e nearest 0.5 g(0.001 lb). Wood for this test method shall be Southern Pinesapwood. The sapwood of other wood species may be added tothe testing program and details of the additional wood speciesshall be provided in the final test report.9.2.2 The treated wood specimens used in this procedurerequire
43、 a conditioning period prior to installation or contactwith the fasteners to be evaluated.9.2.2.1 The conditioning of the treated wood specimensshall be accomplished in an environmental chamber at arelative humidity of 95 % with a tolerance for the controllermeasurement device of 63 % and a temperat
44、ure of 32C(90F) with a tolerance on the temperature controller measure-ment of 62C (3F). The treated wood specimens shall be heldin the chamber in these conditions until the treated woodspecimens reach equilibrium. Equilibrium is defined as nomore than a 60.2 % change in a 24-h period of the average
45、mass of ten randomly selected treated wood specimens. Thesemeasurements shall be conducted every 24 h, and mass shall berecorded and the change calculated until such equilibrium isachieved. Conditions for treated wood specimen conditioningshall be the same as the Steady State Moisture Test condition
46、s.9.2.2.2 Moisture content of the treated wood specimen shallbe determined on one of the treated wood specimens. Thebeginning and final moisture content of the treated woodspecimen shall be determined using calibrated meters inaccordance with Test Method D4444 for samples with a knownmoisture adjust
47、ment for the preservative or by oven dryingmethods in accordance with Test Method D4442 for anysample.9.3 Test Samples:9.3.1 When preparation of the fastener specimens and thetreated wood specimens are complete, the fastener specimensshall be installed in contact with the treated wood specimens.9.3.
48、2 The evaluation of the fasteners shall be conducted byinstalling them into the treated wood specimen as done inapplication, that is, by hand driving or power driving with nopre-drilled pilot holes. When the test objective is the compari-son of wood treatments, the use of pilot holes is permitted to
49、reduce variables associated with fastener installation. Fastenerheads shall be installed such that the bottom of the fastenerhead is in contact with the surface of the treated woodspecimen and shall not be installed so deep that the top of thefastener head is below the surface of the treated woodspecimen. Fastener placement shall avoid knots in the wood.Fasteners shall not be installed into sections of the wood thatcontain heartwood as this wood does not accept a uniformchemical treatment.Atest sample shall no longer be consideredvalid
