ASTM G_Laboratory Immersion Corrosion Testing of Metals. August 18, | Author: Description. Designation: G 31 – 72 (Reapproved ). Buy ASTM G() Standard Practice for Laboratory Immersion Corrosion Testing of Metals from SAI Global. Offering ASTM G31 corrosion testing + modified tests to fit your needs and budget . Rapid, high-quality service by experts.

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Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters. Separate and special techniques are employed for the specific evaluation of the susceptibility of metals and alloys to stress corrosion cracking see Ref.

Careful observation is needed to ensure that pitting does not occur during cleaning.

Determination of Metal Corrosion Rate by ASTM G Canadian Laboratory – LCS Laboratory Inc.

It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to astn. The reporting of nonuniform corrosion is discussed below. A large surface-to-mass ratio and a small ratio of edge area to total area are desirable.

A method of electrolytic cleaning is described in Practice G 1. NOTE 1—The flask can be used as a versatile and convenient apparatus to conduct simple immersion tests. If agitation is required, the apparatus can be modified to accept a suitable stirring mechanism, such as a magnetic stirrer. Therefore, at least duplicate specimens should normally be exposed in each test. The values given in parentheses are for information only. Warning- In many cases the corrosion product on the reactive metals titanium and zirconium is a hard and tightly bonded oxide that defies removal by chemical or ordinary mechanical means.

These factors include specimen preparation, apparatus, test conditions, methods of cleaning specimens, evaluation of results, and calculation and reporting of corrosion rates.

A distinction should be made between those occurring underneath the supporting devices concentration cells and those on the surfaces that were freely exposed to the test solution see Guide G The procedures for determining these values are shown in detail in Test Methods E 8. The mechanical property commonly used for comparison is the tensile strength. This can be accomplished by analysis of the solution after corrosion has occurred. Methods of Cleaning Specimens after Test 9.


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The behavior of the specimens in this galvanic couple are compared with that of insulated specimens exposed on the same holder and the galvanic effects noted.

However, the calculations must not be based on mass loss except in qualification tests such as Practices Awhich is usually small but on microsections which show depth of attack. Size px x x x x For example, the accumulation of cupric ions in the testing of copper alloys in intermediate strengths of sulfuric acid will accelerate the corrosion of copper alloys, as compared to the rates that would be obtained if the corrosion products were continually astmm.

However, some of the corrosion products usually adhere to the specimen as a scale and the corrosion rate calculated from the metal content in the solution is not always correct. Where required, the exhausted constituents should be added or a fresh solution provided during the course of the test.

It should be used as a reference to ensure that the test will allow generation of data relevant to the g3-72 with the minimum of interferences.

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This g31-722 also emphasizes the importance of recording all pertinent data and provides a checklist for reporting test data. It is necessary to evaluate this localized corrosion separately from the overall mass loss. Interpretation of Results G 31 — 72 Reapproved Standard Practice for Laboratory Immersion Corrosion Testing of Metals1 This standard is issued under the fixed designation G 31; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision.

Scrubbing with a bristle brush and mild abrasive is the most popular of these methods. Masking may also be used to achieve the desired area ratios but may cause crevice corrosion problems.

For relatively soft metals such as aluminum, magnesium, and copperscrubbing with abrasive powder is not always needed and can mar the surface of the specimen.

This resurfacing may cause some surface work hardening, to an extent which will be determined by the vigor of the surfacing operation, but is not ordinarily significant.


This cracking occurs under conditions of applied or residual tensile stress, and it may b31-72 may not be visible to the unaided eye or upon casual inspection. The suggested apparatus is basic and the apparatus is limited only by the judgment and ingenuity of the investigator.

We are a non-profit group that run this website to share documents. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below. It should be observed, however, that galvanic corrosion can be greatly affected by the area ratios of the respective metals, the distance between the metals and the resistivity of the g31-7. If clad alloys are exposed, special procedures will be required to ensure astmm only the cladding is exposed, unless the purpose is to test astmm ability of the cladding to protect cut edges in the test solution.

This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or asttm. The corrosion rate can be calculated from the concentration of the matrix metal found in the solution and it can be compared to that determined from the mass loss of the specimens. Originally approved in Using the above units for T, A, W, and D, the corrosion rate can be calculated in a variety of units with the following appropriate value of K: Excellent references for the use of statistics in corrosion studies include Ref.

ASTM G31-72_Laboratory Immersion Corrosion Testing of Metals

However, there are cases where this assumption is not valid. Corrosion testing by its very nature precludes sstm standardization. Please help us to share our service with your friends. For other degrees of aeration, the solution should be sparaged with air or synthetic mixtures of air or oxygen with an inert gas.