1、Designation: G 110 92 (Reapproved 2009)Standard 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 desig
2、nation 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 proced
3、ures 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. It sets forth the specimen preparationprocedures and the environmental conditions
4、 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 of the samematerial (see MIL-H-6088 and U.S. Federal Test Method Std.151b). Therefo
5、re 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 rega
6、rded 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 determi
7、ne the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterE3 Guide for Preparation of Metallographic SpecimensE 407 Practice for Microetching Metals and AlloysG1 Practice for Preparing, Cleaning, and Evaluating Cor-r
8、osion Test SpecimensG15 Terminology Relating to Corrosion and CorrosionTestingG67 Test Method for Determining the Susceptibility toIntergranular Corrosion of 5XXX SeriesAluminumAlloysby Mass Loss After Exposure to Nitric Acid (NAMLTTest)G69 Test Method for Measurement of Corrosion Potentialsof Alumi
9、num Alloys2.2 Other Documents:U.S. Military Specification MIL-H-6088 Heat Treatment ofAluminum Alloys3U.S. Federal Test Method, Std. No. 151b Method 822.1,Intergranular Corrosion Test for Aluminum Alloys33. Summary of Practice3.1 This practice consists of immersing etched test speci-mens in a sodium
10、 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 quenching when performed
11、 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 treatable aluminum alloys
12、is often directly related to thequenching conditions applied after solution heat treatment andto the subsequent aging treatment.44.2 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 d
13、oes not deal with the interpretation ofresulting intergranular corrosion. The significance of the extent1This 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 approved M
14、ay 1, 2009. Published May 2009. Originallyapproved in 1992. Last previous edition approved in 2003 as G 11092(2003)1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to
15、 the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk, Building 4, Section D,700 Robbins Avenue, Philadelphia, PA 19111-5094.4Lifka, B. W., and Sprowls, D. O., “Significance of Intergranular Corrosion ofHigh Strength Aluminum Alloy Products,” Lo
16、calized Corrosion Cause of MetalFailure, ASTM STP 516, 1972, pp. 120144.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.and depth of any intergranular corrosion resulting from this testis to be agreed upon between producer and user.5
17、. Reagents5.1 Reagent grade chemicals sodium chloride (NaCl), 70 %nitric acid (HNO3), 48 % hydrofluoric acid (HF), 37 % hydro-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 co
18、nforming to the purity requirements for Specifi-cation D 1193, Type IV reagent water.6. Solutions6.1 Etching cleaner shall 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
19、 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 handling andmixing strong acids to avoid personal injury and damage toapparatus. Care should include use of personal protectiveeq
20、uipment and use of appropriate apparatus and procedures forparticular acids.)NOTE 2The concentration of the 30 % hydrogen peroxide maydegrade; therefore, it should be verified before each use by the procedurestated in Test Method G69.6.3 Metallographic etchant (Kellers etch) shall be preparedas foll
21、ows: 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 beused, depending on the alloy and temper being examined (seePractice E 407) (see 6.2).7. Specimen Preparation7.1 Place an identific
22、ation 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, including cladding, coatings, dirt, oils, andother residues.7.3 Claddings (especially alcladding) shall be removedeither mechanically
23、 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 followed by immersion for 1 min inconcentrated nitric acid. Examine typical specimen crosssections to be certain that cladding has bee
24、n removed.7.4 Organic materials, such as coatings, soil, oils, and otherresidues, should be removed with organic solvents, for ex-ample, acetone (see Practice G1).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 wate
25、r. 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 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 t
26、est 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 test vessel by placing the specimens on glass rods orrubber stoppers. (Rubber stoppers may be deteriorated byhydrogen peroxide
27、.)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 exposure periods of 24 hours ormore may be used by agreement, especially in the case ofcorrosion resistant alloys and tempers (for ex
28、ample, 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.9.3 Examination of specimens.9.3.1 Examine each exposed specimen at a magnification of10 times or less to locate areas of cor
29、rosion 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. Prepare eachsection by mounting and metallographically polishing (seeGuide E3).9.3.3 Examine the unetched polished surface w
30、ith 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 structure by immersionin the metallographic etchant solution for 6 to 20 s, rinse, dry,and reexamine at 500 times.9.4 Compare
31、or document the type, extent, and depth ofintergranular corrosion in accordance with criteria establishedbetween producer and 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 Comp
32、osition 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,10.1.6 Notation of any deviation in test procedure from thatset forth in preceding paragraphs,10.1.7 Disposition of specimen, and10
33、.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 required?10.2.3 Evaluation criteria utilized.G 110 92 (2009)211. Keywords11.1 2XXX aluminum alloys; 6XXX aluminum alloys;7XXX aluminum alloys; hea
34、t treatable aluminum alloys;intergranular corrosion; intercrystalline corrosionASTM International takes no position respecting 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 vali
35、dity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard 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 comm
36、ents are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International 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
37、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, 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 (2009)3
