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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The others are used principally as a supplement to remove heavily encrusted corrosion products before scrubbing. This practice, rather than a standardized procedure, is presented as a guide so that some of the pitfalls of such testing may be avoided.

Therefore, at least duplicate specimens should normally be exposed in each test. A commercial surface may sometimes yield the most significant results. 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 further corrosion is negligible.

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. 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 removed.

This practice also emphasizes the importance of recording all pertinent data and provides a checklist for reporting test data. Scrubbing with a bristle brush and mild abrasive is the most popular of these methods.


Link to Active This link will always route to the current Active version of the standard.

ASTM G_Laboratory Immersion Corrosion Testing of Metals – Free Download PDF

Proper astn procedures are an acceptable alternate. Therefore, short tests on such materials would g317-2 a high corrosion rate and be completely misleading.

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 is impractical to propose an inflexible standard laboratory corrosion testing procedure for general use, except for material qualification tests where standardization is obviously required. 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, are entirely their own responsibility.

Molarity and normality are also helpful in defining the concentration of chemicals in some test solutions. The degree of lateral spreading of pits may also be noted. However, the absence of cracking should not be interpreted as indicating resistance see 4. However, some of the corrosion products usually adhere to the specimen as a scale and the corrosion rate calculated from the metal content in aztm solution is not always correct. A typical resin flask setup for this type test is shown in Fig.

Excellent references for the g31-722 of statistics in corrosion studies include Ref.

A superscript epsilon e indicates an editorial change since the last revision or reapproval. There are a number of other special types of phenomena of which one must be aware in the design and g1-72 of corrosion tests. Please copy and paste this embed script to where you want to embed Embed Script.

It is necessary to evaluate this localized corrosion separately from the overall mass loss.


These ratios can be g3-172 through the use of square or circular specimens of minimum thickness. However, there are cases where this assumption is not valid.

Other procedures that require the removal of solid corrosion products f31-72 exposure periods will not measure accurately the normal changes of corrosion with time. These factors include apparatus, sampling, test specimen, test conditions test solution composition, temperature, gas sparging, fluid motion, solution volume, method of supporting test specimens, duration of testmethods of cleaning test specimens, interpretation of results, and calculation of corrosion rates.

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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. The mass loss during the test period can be used as the principal measure of corrosion.

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. 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.

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. A liquid atmospheric seal is required on the test vessel to prevent further contamination.