1、Designation: G110 92 (Reapproved 2015)Standard Practice forEvaluating Intergranular Corrosion Resistance of HeatTreatable Aluminum Alloys by Immersion in SodiumChloride + Hydrogen Peroxide Solution1This standard is issued under the fixed designation G110; the number immediately following the designa
2、tion indicates the year oforiginal adoption or, in the case 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. Scope1.1 This practice covers the procedur
3、es for immersion testsin sodium chloride + hydrogen peroxide solution. It is primar-ily for tests of wrought heat treatable aluminum alloys (2XXXand 7XXX) but may be used for other aluminum alloys,including castings. It sets forth the specimen preparationprocedures and the environmental conditions o
4、f the test and themeans for controlling them.1.2 This practice is intended for evaluations during alloydevelopment and for evaluating production where it may serveas a control test on the quality of successive lots of the samematerial (see MIL-H-6088 and U.S. Federal Test Method Std.151b). Therefore
5、 strict test conditions are stipulated for maxi-mum assurance that variations in results are attributable tolot-to-lot differences in the material being tested.NOTE 1This practice does not address sampling or interpretation orsignificance of results.1.3 The values stated in SI units are to be regard
6、ed asstandard. No other units of measurement are included in thisstandard.1.4 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
7、 the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE3 Guide for Preparation of Metallographic SpecimensE407 Practice for Microetching Metals and AlloysG1 Practice for Preparing, Cleaning, and Evaluating Corro-sio
8、n Test SpecimensG15 Terminology Relating to Corrosion and Corrosion Test-ing (Withdrawn 2010)3G67 Test Method for Determining the Susceptibility toIntergranular Corrosion of 5XXX Series Aluminum Al-loys by Mass LossAfter Exposure to NitricAcid (NAMLTTest)G69 Test Method for Measurement of Corrosion
9、Potentialsof Aluminum Alloys2.2 Other Documents:U.S. Military Specification MIL-H-6088 Heat Treatment ofAluminum Alloys4U.S. Federal Test Method, Std. No. 151b Method 822.1,Intergranular Corrosion Test for Aluminum Alloys43. Summary of Practice3.1 This practice consists of immersing etched test spec
10、i-mens in a sodium chloride + hydrogen peroxide solution for 6or more hours. After immersion, metallographic sections areexamined to determine the extent of intergranular corrosion(see Terminology G15).4. Significance and Use4.1 This practice is especially useful for evaluating theadequacy of quench
11、ing when performed on material in theas-quenched condition. The practice may also be used to studythe effect of subsequent thermal processes (for example, paintor bonding cures) or of actual precipitation treatments on theinherent type of corrosion. Intergranular corrosion resistance ofheat treatabl
12、e aluminum alloys is often directly related to thequenching conditions applied after solution heat treatment andto the subsequent aging treatment.51This practice is under the jurisdiction of ASTM Committee G01 on Corrosionof Metals and is the direct responsibility of Subcommittee G01.05 on Laborator
13、yCorrosion Tests.Current edition approved Dec. 1, 2015. Published December 2015. Originallyapproved in 1992. Last previous edition approved in 2009 as G11092(2009). DOI:10.1520/G0110-92R15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at servic
14、eastm.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.4Available from Standardization Documents Order Desk, Building 4, Section D,700 Robbins
15、Avenue, Philadelphia, PA 19111-5094.5Lifka, B. W., and Sprowls, D. O., “Significance of Intergranular Corrosion ofHigh Strength Aluminum Alloy Products,” Localized Corrosion Cause of MetalFailure, ASTM STP 516, 1972, pp. 120144.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West C
16、onshohocken, PA 19428-2959. United States14.2 This practice is not well suited for non-heat treatablework hardening aluminum alloys, such as the 1XXX, 3XXX,and 5XXX series (see Test Method G67).4.3 This practice does not deal with the interpretation ofresulting intergranular corrosion. The significa
17、nce of the extentand depth of any intergranular corrosion resulting from this testis to be agreed upon between producer and user.5. Reagents5.1 Reagent grade chemicals sodium chloride (NaCl), 70 %nitric acid (HNO3), 48 % hydrofluoric acid (HF), 37 % hydro-chloric acid (HCl), and 30 % hydrogen peroxi
18、de (H2O2) shallbe used for preparation of all solutions.5.2 The solutions shall be prepared using distilled or deion-ized water conforming to the purity requirements for Specifi-cation D1193, Type IV reagent water.6. Solutions6.1 Etching cleaner shall be prepared as follows: To 945 mLof reagent wate
19、r add 50 mL of nitric acid (70 %) + 5 mL ofhydrofluoric acid (48 %). (See 6.2).6.2 Test solution shall be prepared as follows: 57 grams ofsodium chloride +10 mL of hydrogen peroxide (30 %addjust prior to initiation of exposure) diluted to 1.0 L with reagentwater. (WarningCare should be exercised in
20、handling andmixing strong acids to avoid personal injury and damage toapparatus. Care should include use of personal protectiveequipment and use of appropriate apparatus and procedures forparticular acids.)NOTE 2The concentration of the 30 % hydrogen peroxide maydegrade; therefore, it should be veri
21、fied before each use by the procedurestated in Test Method G69.6.3 Metallographic etchant (Kellers etch) shall be preparedas follows: To 95 mL of reagent water add 2.5 mL of nitric acid(70 %) + 1.5 mL of hydrochloric acid (37 %) + 1.0 mL ofhydrofluoric acid (48 %). A number of other etchants may beu
22、sed, depending on the alloy and temper being examined (seePractice E407) (see 6.2).7. Specimen Preparation7.1 Place an identification mark on each specimen in an areathat will not be subject to metallographic examination.7.2 The entire surface of the specimen must be free of allforeign matter, inclu
23、ding cladding, coatings, dirt, oils, andother residues.7.3 Claddings (especially alcladding) shall be removedeither mechanically or chemically to a depth of at least twicethe nominal cladding thickness. Chemical removal can beaccomplished by immersion in a 5 % sodium hydroxidesolution at 140F follow
24、ed by immersion for 1 min inconcentrated nitric acid. Examine typical specimen crosssections to be certain that cladding has been removed.7.4 Organic materials, such as coatings, soil, oils, and otherresidues, should be removed with organic solvents, forexample, acetone (see Practice G1).7.5 Prior t
25、o immersion in the test solution, immerse eachspecimen for 1 min in the etching cleaner (see 6.1) at 93C.Rinse in reagent water. Immerse in concentrated nitric acid(70 %) for 1 min. Rinse in reagent water and air dry.8. Test Setup8.1 The test vessel should be of nonmetallic material ofsufficient siz
26、e to hold at least 5 mL of test solution per squarecm of specimen surface area.8.2 More than one specimen may be placed in a test vessel,provided specimens do not contact each other and providedcondition outlined in 8.1 is observed.8.3 Specimens shall be prevented from contacting the bot-tom of the
27、test vessel by placing the specimens on glass rods orrubber stoppers. (Rubber stoppers may be deteriorated byhydrogen peroxide.)8.4 The exposure shall be conducted at a temperature of 306 3C.9. Procedure9.1 Immerse the etched specimens in the test solution for aperiod of at least 6 h. Longer exposur
28、e periods of 24 hours ormore may be used by agreement, especially in the case ofcorrosion resistant alloys and tempers (for example, 6XXXalloys). Shorter exposure periods of less than 6 h may beappropriate for very thin sheet.9.2 After exposure, rinse each specimen with reagent waterand allow to dry
29、.9.3 Examination of specimens.9.3.1 Examine each exposed specimen at a magnification of10 times or less to locate areas of corrosion attack.9.3.2 Prepare at least one metallographic cross sectionapproximately 20 mm in length from each specimen, prefer-ably through a corroded area identified in 9.3.1
30、. Prepare eachsection by mounting and metallographically polishing (seeGuide E3).9.3.3 Examine the unetched polished surface with a metal-lograph at magnifications of 100 to 500 times. If there isuncertainty as to the presence of intergranular corrosion, etchthe polished surface to reveal the grain
31、structure by immersionin the metallographic etchant solution for 6 to 20 s, rinse, dry,and reexamine at 500 times.9.4 Compare or document the type, extent, and depth ofintergranular corrosion in accordance with criteria establishedbetween producer and purchaser.10. Documentation10.1 The following es
32、sential information should be re-corded for each specimen:10.1.1 Identification of the heat or lot of the material,10.1.2 Composition or standard alloy identification andtemper,10.1.3 Product form: sheet, plate, extrusion, forging, orcasting,10.1.4 Sampling location,10.1.5 Duration of exposure,G110
33、92 (2015)210.1.6 Notation of any deviation in test procedure from thatset forth in preceding paragraphs,10.1.7 Disposition of specimen, and10.1.8 Results of microscopic examination.10.2 Other information that may be desirable:10.2.1 Number of sections examined.10.2.2 Was metallographic etching requi
34、red?10.2.3 Evaluation criteria utilized.11. Keywords11.1 2XXX aluminum alloys; 6XXX aluminum alloys;7XXX aluminum alloys; heat treatable aluminum alloys;intergranular corrosion; intercrystalline corrosionASTM International takes no position respecting the validity of any patent rights asserted in co
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37、 consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International,
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