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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Determination of Metal Corrosion Rate by ASTM G31-72. Canadian Laboratory

Methods of Cleaning Specimens after Test 9. Significance and Use 3. Scrubbing with a bristle brush and mild abrasive is the most popular of these methods. Thank you for interesting in our services.

Measurement of percent elongation is a useful index of embrittlement. The mass loss during the test period can be used as the principal measure of corrosion. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, aastm entirely their own responsibility.

The reporting of nonuniform corrosion is discussed below.

The actual time of contact of the metal with the solution must also be taken into account. This cannot be evaluated by mass loss alone. In special cases for example, for aluminum and certain copper alloysa minimum of 24 h storage in a desiccator is recommended. Close attention and a more sophisticated evaluation than a simple mass loss measurement are required to detect this phenomenon.

Link to Active This link will always route to the current Active version of the standard. The surface finish to be encountered in service may be more appropriate for some testing.


Careful observation is needed to ensure that pitting does not occur during cleaning. NOTE 1—The flask can be used as a versatile and convenient apparatus to conduct simple immersion tests. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.

The phenomenon of forming a protective film is observed with many corrosion-resistant materials. Localized corrosion is reported separately. It may be desirable to test a surface representative of the material and metallurgical conditions used in practice.

The values given in parentheses are for information only.

The most common testing periods are 48 to h 2 to 7 days. A number in parentheses indicates the year of last reapproval. For example, lead exposed to sulfuric acid corrodes at an extremely high rate at first, while building a protective film; then the rates decrease considerably so that zstm corrosion is negligible.

ASTM G31-72_Laboratory Immersion Corrosion Testing of Metals

We are a non-profit group that run this website to share documents. Methods for chemical cleaning after testing of specific metals and alloys are described in Practice G 1. 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.

Extraneous effects can be encountered if the air stream impinges on the specimens. ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard.

ASTM NACE / ASTMG31 – 12a Standard Guide for Laboratory Immersion Corrosion Testing of Metals

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. Occasional exceptions, in which a large difference is observed, can occur under conditions of borderline passivity of metals or alloys that depend on a passive film for their resistance to corrosion.


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 use.

A large surface-to-mass ratio and a small ratio of edge area to total area are desirable. 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.

The use of towels for drying may introduce an error through contamination of the specimens with grease or lint. Interpretation of Results Most tests related to process equipment should be run with the natural atmosphere inherent in the process, such as the vapors of the boiling liquid.

With a thickness of approximately 3 mm 0. 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 It should be used as a sstm to ensure that the test will allow generation of data relevant to the application with the minimum of interferences.

For solutions corrosive to glass, suitable metallic or plastic kettles may be employed.