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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Location of deposits, variations in types of deposits, or variations in corrosion products are extremely important in evaluating localized corrosion, such as pitting and concentration cell attack.

It is necessary to evaluate this localized corrosion separately from the overall mass loss. Historical Version s – view previous versions of standard.

ASTM G31-72_Laboratory Immersion Corrosion Testing of Metals

If this is a factor to be considered in a specific test, the solution should be completely aerated or deaerated in accordance with 8. Cupric ions may also exhibit a passivating effect upon stainless steel astk exposed at the same time. Special coupons for example, sections of welded tubing may be employed for specific purposes.

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.

Masking may also be used to achieve the desired area ratios but may cause crevice corrosion problems. A typical resin flask setup for this type test is shown in Fig. The use of towels for drying may introduce an error through contamination of the specimens with grease xstm lint.


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

We need your help to maintenance this website. For example, a small coupon is not as prone to exhibit pitting as a large one and it is possible to miss the phenomenon altogether in the corrosion testing of certain alloys, such as the AISI Type series stainless steels in chloride contaminated environments.

Measurement of percent elongation is a useful index of embrittlement. 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 Extraneous effects can be encountered if the air stream impinges on 3g1-72 specimens. After final preparation of the specimen surface, the specimens should be stored in a desiccator until exposure, if they are not used immediately.

This cracking occurs under conditions of applied or residual tensile stress, and it may or may not be visible to the unaided eye or upon casual inspection. One purpose for this guide is to promote better correlation of results in the future and the reduction of conflicting reports through a more detailed recording of meaningful factors and conditions.

ASTM G31 – 72() Standard Practice for Laboratory Immersion Corrosion Testing of Metals

For example, the accumulation of astmm 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 removed. A superscript epsilon e indicates an editorial change since the last revision or reapproval.

Oxygen saturation is a function of the partial pressure of oxygen asgm the gas. The phenomenon of forming a protective film is observed with many corrosion-resistant materials.


In practice, only alloys of the same general type should be exposed in the testing apparatus.

However, the absence of cracking should not be interpreted as indicating resistance see 4. With borderline conditions, a prolonged test may be needed to permit breakdown of asstm passive film and subsequent more rapid attack. The choice of a specific treatment must be considered on the basis of the alloy to be tested and the reasons for testing.

The mechanical property commonly used for comparison is the tensile strength. This standard does not purport to address all of the safety concerns, if any, associated with its use. Solvents such as acetone, carbon tetrachloride, and alcohol are used to remove oil, grease, or resin and are usually applied prior to other methods of cleaning.

However, some of the corrosion products usually adhere to the specimen as a scale b31-72 the corrosion rate calculated from the metal content in the solution is not always correct.

With a thickness of approximately 3 mm 0.

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

Alternatively, the coupon may be rotated through the environment, although it is then difficult to evaluate the velocity quantitatively because of the stirring effects incurred. Thank you for interesting in our services.

Excellent references for the use of statistics in corrosion studies include Ref. Originally approved in