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G34 Standard Test Method(EXCO Test) 腐蚀标准

Designation:G34−01(Reapproved 2013)

G34 Standard Test Method(EXCO Test) 腐蚀标准

Standard Test Method for

Exfoliation Corrosion Susceptibility in 2XXX and 7XXX Series Aluminum Alloys (EXCO Test)1

This standard is issued under the fixed designation G34;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon (´)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.

1.Scope

1.1This test method covers a procedure for constant im-mersion exfoliation corrosion (EXCO)testing of high-strength 2XXX and 7XXX series aluminum alloys.

N OTE 1—This test method was originally developed for research and development purposes;however,it is referenced,in specific material specifications,as applicable for evaluating production material (refer to Section 14on Precision and Bias).

1.2This test method applies to all wrought products such as sheet,plate,extrusions,and forgings produced from conven-tional ingot metallurgy process.

1.3This test method can be used with any form of specimen or part that can be immersed in the test solution.

1.4This standard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility 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.

2.Referenced Documents

2.1ASTM Standards:2

D1193Specification for Reagent Water

E3Guide for Preparation of Metallographic Specimens G15Terminology Relating to Corrosion and Corrosion Test-ing (Withdrawn 2010)3

G112Guide for Conducting Exfoliation Corrosion Tests in Aluminum Alloys

2.2ASTM Adjuncts:

Illustrations (Enlarged Glossy Prints)43.Terminology

3.1Definitions:

3.1.1exfoliation—corrosion that proceeds laterally from the sites of initiation along planes parallel to the surface,generally at grain boundaries,forming corrosion products that force metal away from the body of the material giving rise to a layered appearance (Terminology G15).

4.Summary of Test Method

4.1This test method provides an accelerated exfoliation corrosion test for 2XXX and 7XXX series aluminum alloys that involves the continuous immersion of test materials in a solution containing 4M sodium chloride,0.5M potassium nitrate,and 0.1M nitric acid at 2563°C (7765°F).The susceptibility to exfoliation is determined by visual examination,with performance ratings established by refer-ence to standard photographs.

5.Significance and Use

5.1This test method was originally developed for research and development purposes;however,it is referenced,in specific material specifications,as applicable for evaluating production material (refer to Section 14on Precision and Bias).5.2Use of this test method provides a useful prediction of the exfoliation corrosion behavior of these alloys in various types of outdoor service,especially in marine and industrial environments.5The test solution is very corrosive and repre-sents the more severe types of environmental service,excluding,of course,unusual chemicals not likely to be encountered in natural environments.

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This test method is under the jurisdiction of ASTM Committee G01on Corrosion of Metals and is the direct responsibility of Subcommittee G01.05on Laboratory Corrosion Tests.

Current edition approved May 1,2013.Published July 2013.Originally approved in http://www.wendangku.net/doc/5266e4e4af1ffc4ffe47aceb.html st previous edition approved in 2007as G34–01(2007).DOI:10.1520/G0034-01R13.2

For referenced ASTM standards,visit the ASTM website,http://www.wendangku.net/doc/5266e4e4af1ffc4ffe47aceb.html ,or contact ASTM Customer Service at service@http://www.wendangku.net/doc/5266e4e4af1ffc4ffe47aceb.html .For Annual Book of ASTM Standards volume information,refer to the standard’s Document Summary page on the ASTM website.3

The last approved version of this historical standard is referenced on http://www.wendangku.net/doc/5266e4e4af1ffc4ffe47aceb.html .

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Available from ASTM International Headquarters.Order Adjunct No.ADJG003402.Original adjunct produced in 1980.5

Ketcham,S.J.,and Jeffrey,P.W.,“Exfoliation Corrosion Testing of 7178and 7075Aluminum Alloys”(Report of ASTM G01.05Interlaboratory Testing Program in Cooperation with the Aluminum Association);and Sprowls,D.O.,Walsh,J.D.,and Shumaker,M. B.,“Simplified Exfoliation Testing of Aluminum Alloys,”Localized Corrosion—Cause of Metal Failure,ASTM STP 516,ASTM,1972.

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