ASTM G_Laboratory Immersion Corrosion Testing of Metals – Free download as PDF File .pdf), Text File .txt) or read online for free. ASTM G Other ASTM procedures for laboratory corrosion tests are tabulated in the Appendix. NOTE 1—Warning: In many cases the corrosion product on the reac-. ASTM G Standard Practice for Laboratory Immersion Corrosion Testing of Metals_能源/化工_工程科技_专业资料. 暂无评价|0人阅读|0次.
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Where required, the exhausted constituents should be added or a fresh solution provided during the course of the test. For other degrees of aeration, the solution should be sparaged with air or synthetic mixtures of air or oxygen with an inert gas.
A commercial surface may sometimes yield the most signi? This practice, rather astmm a standardized procedure, is presented as a guide so that some of the pitfalls of such testing may be avoided.
In practice, only alloys of the same general type should be exposed in the testing apparatus. For proper interpretation of the results obtained, the speci? A large surface-to-mass ratio and a small ratio of edge area to total area are desirable. However, the absence of cracking should not be interpreted as indicating resistance see 4. Most tests atsm to process equipment should sstm run with the natural atmosphere inherent in the process, such as the vapors of the boiling liquid.
Warning—In many cases the corrosion product on the reactive metals titanium and asfm is a hard and tightly bonded oxide that de?
This cannot be evaluated by mass loss alone. 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. Separate and special techniques are employed for the speci?
It is the astn of the user of this standard to g3 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 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. In many such cases, corrosion rates are established by mass gain rather than mass loss. The total surface area of a circular specimen is given by the following equation: The procedures for determining these values are shown in detail in Test Methods E 8.
This practice also emphasizes the importance of recording all pertinent data and provides a checklist for reporting test data.
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: NOTE 1—If desired, these constants may also be used to convert corrosion rates from one set of units to another. 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.
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ASTM NACE / ASTMG31 – 12a Standard Guide for Laboratory Immersion Corrosion Testing of Metals
Careful observation is needed to ensure that pitting does not occur during cleaning. In special cases for example, for aluminum and certain copper alloysa minimum of 24 h storage in a desiccator is recommended.
It is the responsibility of the user of 3g1 standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Cupric ions may also exhibit a passivating effect upon stainless steel coupons exposed at the same time.
Proper ultrasonic procedures are an acceptable alternate. It is necessary to evaluate this localized corrosion separately from the overall mass loss. It is impractical to propose an in? 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. If metallic contamination of the stamped area may in?
Other procedures that require the removal of solid corrosion products between exposure periods will not measure accurately the normal changes of corrosion with time. These changes should be determined if possible. There are a number of other special types of phenomena of which one must be aware in the design and interpretation of corrosion tests. Preferably, the use of a re? The mechanical property commonly used for comparison is the tensile strength.
Originally approved in Therefore, short tests on such materials would indicate a high corrosion rate and be completely misleading. Link to Active This link will always route to the current Active version of the standard. Link to Active This link will always route to the current Active version of the standard. It is imperative to note that this usually occurs with no signi? This can be done by chemical treatment picklingelectrolytic removal, or by grinding with a coarse abrasive paper or cloth such as No.
Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters. The density in the constant K cancels out the density in the corrosion rate equation.
A number in parentheses indicates the year of last reapproval. 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.
These factors include apparatus, sampling, test specimen, test conditions test solution g3, 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. 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.
The amount of possible contamination can astmm estimated from the loss in mass of the specimen, with proper application of the expected relationships among 1 the satm of corroding surface, g311 the mass of the chemical product handled, and 3 the duration of contact of a unit of mass of the chemical product with the corroding surface. If clad alloys are exposed, special procedures will be required to ensure that only the cladding is exposed, unless the purpose is to test the ability of the cladding to protect cut edges in the test solution.
The phenomenon of forming a protective?