1、Designation: G1 03 (Reapproved 2017)1Standard Practice forPreparing, Cleaning, and Evaluating Corrosion TestSpecimens1This standard is issued under the fixed designation G1; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year
2、of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.1NOTEEditorially updated references in Section 2 in December 2017.1. Scope1.1 This practice covers suggested procedures for prepari
3、ngbare, solid metal specimens for tests, for removing corrosionproducts after the test has been completed, and for evaluatingthe corrosion damage that has occurred. Emphasis is placed onprocedures related to the evaluation of corrosion by mass lossand pitting measurements. (WarningIn many cases thec
4、orrosion product on the reactive metals titanium and zirco-nium is a hard and tightly bonded oxide that defies removal bychemical or ordinary mechanical means. In many such cases,corrosion rates are established by mass gain rather than massloss.)1.2 The values stated in SI units are to be regarded a
5、sstandard. No other units of measurement are included in thisstandard.1.3 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, health, and environmental practices a
6、nd deter-mine the applicability of regulatory limitations prior to use.For specific warning statements, see 1.1 and 7.2.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelop
7、ment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2A262 Practices for Detecting Susceptibility to IntergranularAttack in Austenitic Stainless SteelsD1193 Specificati
8、on for Reagent WaterD1384 Test Method for Corrosion Test for Engine Coolantsin GlasswareD2776 Methods of Test for Corrosivity of Water in theAbsence of Heat Transfer (Electrical Methods) (With-drawn 1991)3G16 Guide for Applying Statistics to Analysis of CorrosionDataG31 Guide for Laboratory Immersio
9、n Corrosion Testing ofMetalsG33 Practice for Recording Data from Atmospheric Corro-sion Tests of Metallic-Coated Steel SpecimensG46 Guide for Examination and Evaluation of Pitting Cor-rosionG50 Practice for Conducting Atmospheric Corrosion Testson MetalsG78 Guide for Crevice Corrosion Testing of Iro
10、n-Base andNickel-Base Stainless Alloys in Seawater and OtherChloride-Containing Aqueous EnvironmentsG193 Terminology and Acronyms Relating to Corrosion3. Terminology3.1 See Terminology G193 for terms used in this practice.4. Significance and Use4.1 The procedures given are designed to remove corrosi
11、onproducts without significant removal of base metal.This allowsan accurate determination of the mass loss of the metal or alloythat occurred during exposure to the corrosive environment.4.2 These procedures, in some cases, may apply to metalcoatings. However, possible effects from the substrate mus
12、t beconsidered.5. Reagents and Materials5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended that1This practice is under the jurisdiction of ASTM Committee G01 on Corrosionof Metals and is the direct responsibility of Subcommittee G01.05
13、 on LaboratoryCorrosion Tests.Current edition approved Nov. 1, 2017. Published December 2017. Originallyapproved in 1967. Last previous edition approved in 2011 as G1 03 (2011). DOI:10.1520/G0001-03R17E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer S
14、ervice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West C
15、onshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade
16、 Organization Technical Barriers to Trade (TBT) Committee.1all reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.4Other grades may be used,provided it is first ascertained that the reagent is of suffi
17、cientlyhigh purity to permit its use without lessening the accuracy ofthe determination.5.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type IV of Specification D1193.6. Methods for Preparing Specimens for Test6.1 For laborator
18、y corrosion tests that simulate exposure toservice environments, a commercial surface, closely resem-bling the one that would be used in service, will yield the mostmeaningful results.6.2 It is desirable to mark specimens used in corrosion testswith a unique designation during preparation. Several t
19、ech-niques may be used depending on the type of specimen andtest.6.2.1 Stencil or StampMost metallic specimens may bemarked by stenciling, that is, imprinting the designation codeinto the metal surface using hardened steel stencil stamps hitwith a hammer. The resulting imprint will be visible even a
20、ftersubstantial corrosion has occurred. However, this procedureintroduces localized strained regions and the possibility ofsuperficial iron contamination in the marked area.6.2.2 Electric engraving by means of a vibratory markingtool may be used when the extent of corrosion damage isknown to be smal
21、l. However, this approach to marking is muchmore susceptible to having the marks lost as a result ofcorrosion damage during testing.6.2.3 Edge notching is especially applicable when extensivecorrosion and accumulation of corrosion products is antici-pated. Long term atmospheric tests and sea water i
22、mmersiontests on steel alloys are examples where this approach isapplicable. It is necessary to develop a code system when usingedge notches.6.2.4 Drilled holes may also be used to identify specimenswhen extensive metal loss, accumulation of corrosion products,or heavy scaling is anticipated. Drille
23、d holes may be simplerand less costly than edge notching. A code system must bedeveloped when using drilled holes. Punched holes should notbe used as they introduce residual strain.6.2.5 When it is undesirable to deform the surface ofspecimens after preparation procedures, for example, whentesting c
24、oated surfaces, tags may be used for specimen identi-fication.Ametal or plastic wire can be used to attach the tag tothe specimen and the specimen identification can be stampedon the tag. It is important to ensure that neither the tag nor thewire will corrode or degrade in the test environment. It i
25、s alsoimportant to be sure that there are no galvanic interactionsbetween the tag, wire, and specimen.6.3 For more searching tests of either the metal or theenvironment, standard surface finishes may be preferred. Asuitable procedure might be:6.3.1 Degrease in an organic solvent or hot alkaline clea
26、ner.(See also Practice G31.)NOTE 1Hot alkalies and chlorinated solvents may attack some metals.NOTE 2Ultrasonic cleaning may be beneficial in both pre-test andpost-test cleaning procedures.6.3.2 Pickle in an appropriate solution if oxides or tarnishare present. In some cases the chemical cleaners de
27、scribed inSection 6 will suffice.NOTE 3Pickling may cause localized corrosion on some materials.6.3.3 Abrade with a slurry of an appropriate abrasive or withan abrasive paper (see Practices A262 and Test MethodD1384). The edges as well as the faces of the specimens shouldbe abraded to remove burrs.6
28、.3.4 Rinse thoroughly, hot air dry, and store in desiccator.6.4 When specimen preparation changes the metallurgicalcondition of the metal, other methods should be chosen or themetallurgical condition must be corrected by subsequent treat-ment. For example, shearing a specimen to size will cold worka
29、nd may possibly fracture the edges. Edges should be ma-chined.6.5 The clean, dry specimens should be measured andweighed. Dimensions determined to the third significant figureand mass determined to the fifth significant figure are sug-gested. When more significant figures are available on themeasuri
30、ng instruments, they should be recorded.7. Methods for Cleaning After Testing7.1 Corrosion product removal procedures can be dividedinto three general categories: mechanical, chemical, and elec-trolytic.7.1.1 An ideal procedure should remove only corrosionproducts and not result in removal of any ba
31、se metal. Todetermine the mass loss of the base metal when removingcorrosion products, replicate uncorroded control specimensshould be cleaned by the same procedure being used on the testspecimen. By weighing the control specimen before and aftercleaning, the extent of metal loss resulting from clea
32、ning canbe utilized to correct the corrosion mass loss.NOTE 4It is desirable to scrape samples of corrosion products beforeusing any chemical techniques to remove them. These scrapings can thenbe subjected to various forms of analyses, including perhaps X-raydiffraction to determine crystal forms as
33、 well as chemical analyses to lookfor specific corrodants, such as chlorides. All of the chemical techniquesthat are discussed in Section 7 tend to destroy the corrosion products andthereby lose the information contained in these corrosion products. Caremay be required so that uncorroded metal is no
34、t removed with thecorrosion products.7.1.2 The procedure given in 7.1.1 may not be reliable whenheavily corroded specimens are to be cleaned. The applicationof replicate cleaning procedures to specimens with corrodedsurfaces will often, even in the absence of corrosion products,result in continuing
35、mass losses. This is because a corrodedsurface, particularly of a multiphase alloy, is often moresusceptible than a freshly machined or polished surface to4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagent
36、s notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.G1 03 (2017)12corrosion by the cleaning procedure. In such cas
37、es, thefollowing method of determining the mass loss due to thecleaning procedure is preferred.7.1.2.1 The cleaning procedure should be repeated on speci-mens several times. The mass loss should be determined aftereach cleaning by weighing the specimen.7.1.2.2 The mass loss should be graphed as a fu
38、nction of thenumber of equal cleaning cycles as shown in Fig. 1. Two lineswill be obtained: AB and BC. The latter will correspond tocorrosion of the metal after removal of corrosion products. Themass loss due to corrosion will correspond approximately topoint B.7.1.2.3 To minimize uncertainty associ
39、ated with corrosionof the metal by the cleaning method, a method should bechosen to provide the lowest slope (near to horizontal) of lineBC.7.1.3 Repeated treatment may be required for completeremoval of corrosion products. Removal can often be con-firmed by examination with a low power microscope (
40、forexample, 7 to 30). This is particularly useful with pittedsurfaces when corrosion products may accumulate in pits. Thisrepeated treatment may also be necessary because of therequirements of 7.1.2.1. Following the final treatment, thespecimens should be thoroughly rinsed and immediately dried.7.1.
41、4 All cleaning solutions shall be prepared with waterand reagent grade chemicals.7.2 Chemical procedures involve immersion of the corro-sion test specimen in a specific solution that is designed toremove the corrosion products with minimal dissolution of anybase metal. Several procedures are listed
42、in Table A1.1. Thechoice of chemical procedure to be used is partly a matter oftrial and error to establish the most effective method for aspecific metal and type of corrosion product scale.(WarningThese methods may be hazardous to personnel).7.2.1 Chemical cleaning is often preceded by light brushi
43、ng(non metallic bristle) or ultrasonic cleaning of the test speci-men to remove loose, bulky corrosion products.7.2.2 Intermittent removal of specimens from the cleaningsolution for light brushing or ultrasonic cleaning can oftenfacilitate the removal of tightly adherent corrosion products.7.2.3 Che
44、mical cleaning is often followed by light brushingor ultrasonic cleaning in reagent water to remove looseproducts.7.3 Electrolytic cleaning can also be utilized for removal ofcorrosion products. Several useful methods for corrosion testspecimens of iron, cast iron, or steel are given in Table A2.1.7
45、.3.1 Electrolytic cleaning should be preceded by brushingor ultrasonic cleaning of the test specimen to remove loose,bulky corrosion products. Brushing or ultrasonic cleaningshould also follow the electrolytic cleaning to remove anyloose slime or deposits. This will help to minimize anyredeposition
46、of metal from reducible corrosion products thatwould reduce the apparent mass loss.7.4 Mechanical procedures can include scraping, scrubbing,brushing, ultrasonic cleaning, mechanical shocking, and im-pact blasting (for example, grit blasting, water-jet blasting, andso forth). These methods are often
47、 utilized to remove heavilyencrusted corrosion products. Scrubbing with a nonmetallicbristle brush and a mild abrasive-distilled water slurry can alsobe used to remove corrosion products.7.4.1 Vigorous mechanical cleaning may result in the re-moval of some base metal; therefore, care should be exerc
48、ised.These should be used only when other methods fail to provideadequate removal of corrosion products. As with othermethods, correction for metal loss due to the cleaning methodis recommended. The mechanical forces used in cleaningshould be held as nearly constant as possible.8. Assessment of Corr
49、osion Damage8.1 The initial total surface area of the specimen (makingcorrections for the areas associated with mounting holes) andthe mass lost during the test are determined. The averagecorrosion rate may then be obtained as follows:Corrosion Rate 5 K 3 W!/A 3 T 3 D! (1)where:K = a constant (see 8.1.2),T = time of exposure in hours,A = area in cm2,W = mass loss in grams, andD = density in g/cm3(see Appendix X1).8.1.1 Corrosion rates are not necessarily constant with timeof exposure. See Practice G31 for further guidance.8.1.2 Many different units are used to expre
