1、Designation: G 110 92 (Reapproved 2003)e1Standard Practice forEvaluating Intergranular Corrosion Resistance of HeatTreatable Aluminum Alloys by Immersion in SodiumChloride + Hydrogen Peroxide Solution1This standard is issued under the fixed designation G 110; the number immediately following the des
2、ignation 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 (e) indicates an editorial change since the last revision or reapproval.e1NOTEWarning notes were editorially mov
3、ed into main body text in October 2003.1. Scope1.1 This practice covers the procedures for immersion testsin sodium chloride + hydrogen peroxide solution. It is prima-rily for tests of wrought heat treatable aluminum alloys (2XXXand 7XXX) but may be used for other aluminum alloys,including castings.
4、 It sets forth the specimen preparationprocedures and the environmental conditions of 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 o
5、f the samematerial (see MIL-H-6088 and U.S. Federal Test Method Std.151b). Therefore 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 interpr
6、etation orsignificance of results.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 and health practices and determine the applica-bility of regulatory limita
7、tions prior to use.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2E 3 Methods of Preparation of Metallographic Specimens3E 407 Test Methods for Microetching Metals and Alloys3G 1 Practice for Preparing, Cleaning, and Evaluating Cor-rosion Test Specimens4G 15 Termino
8、logy Relating to Corrosion and CorrosionTesting4G 67 Test Method for Determining the Susceptibility toIntergranular Corrosion of 5XXX Series Aluminum Alloysby Mass Loss After Exposure to Nitric Acid (NAMLTTest)4G 69 Practice for Measurement of Corrosion Potentials ofAluminum Alloys42.2 Other Documen
9、ts:U.S. Military Specification MIL-H-6088, Heat Treatment ofAluminum Alloys5U.S. Federal Test Method, Standard No.151b, Method 822.1, Intergranular Corrosion Test forAluminum Alloys53. Summary of Practice3.1 This practice consists of immersing etched test speci-mens in a sodium chloride + hydrogen p
10、eroxide solution for 6or more hours. After immersion, metallographic sections areexamined to determine the extent of intergranular corrosion(see Terminology G 15).4. Significance and Use4.1 This practice is especially useful for evaluating theadequacy of quenching when performed on material in theas
11、-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 treatable aluminum alloys is often directly rel
12、ated to thequenching conditions applied after solution heat treatment andto the subsequent aging treatment.61This practice is under the jurisdiction of ASTM Committee G01 on Corrosionof Metals and is the direct responsibility of Subcommittee G01.05 on LaboratoryCorrosion Tests.Current edition approv
13、ed October 1, 2003. Published October 2003. Originallyapproved in 1992. Last previous edition approved in 1997 as G 110 92 (1997).2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 03.01.4Annual Book of ASTM Standards, Vol 03.02.5Available from Standardization Documents Or
14、der Desk, Building 4, Section D,700 Robbins Avenue, Philadelphia, PA 19111-5094.6Lifka, 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. 120144.1Copyright ASTM Internation
15、al, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2 This practice is not well suited for non-heat treatablework hardening aluminum alloys, such as the 1XXX, 3XXX,and 5XXX series (see Test Method G 67).4.3 This practice does not deal with the interpretation ofr
16、esulting intergranular corrosion. The significance 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 % hyd
17、ro-chloric acid (HCl), and 30 % hydrogen peroxide (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 D 1193, Type IV reagent water.6. Solutions6.1 Etching cleaner shall
18、be prepared as follows: To 945 mLof reagent water 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 re
19、agentwater. (WarningCare should be exercised in 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 p
20、eroxide maydegrade; therefore, it should be verified before each use by the procedurestated in Practice G 69.6.3 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 a
21、cid (48 %). A number of other etchants may beused, depending on the alloy and temper being examined (seeMethod E 407) (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 spec
22、imen must be free of allforeign matter, including 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
23、a 5 % sodium hydroxidesolution at 140F followed 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, for
24、ex-ample, acetone (see Practice G 1).7.5 Prior to 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 sh
25、ould be of nonmetallic material ofsufficient size 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
26、be prevented from contacting the bot-tom of the 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 solu
27、tion for aperiod of at least 6 h. Longer exposure 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
28、each specimen with reagent waterand allow to dry.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-
29、ably through a corroded area identified in 9.3.1. Prepare eachsection by mounting and metallographically polishing (seeMethod E 3).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 corros
30、ion, etchthe polished surface to reveal the grain 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 an
31、d purchaser.10. Documentation10.1 The following essential 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 S
32、ampling location,10.1.5 Duration of exposure,10.1.6 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
33、.2 Was metallographic etching required?G 110 92 (2003)e1210.2.3 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 respec
34、ting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This sta
35、ndard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Internati
36、onal Headquarters. Your comments will receive careful 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
37、.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).G 110 92 (2003)e13
