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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Duplicate strips of low-carbon steel, each 19 by 76 mm 3?
Immersion Corrosion Testing According to ASTM G31 Standard
Special coupons for example, sections of welded tubing may be employed for speci? 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. Circular specimens should preferably be cut from sheet and not bar stock, to minimize the exposed end grain. These changes should be determined if asrm.
Generally, if cracking is observed on the coupon, it can be taken as positive indication of susceptibility, whereas failure to effect this phenomenon simply means that it did not occur under the duration and speci? A number in parentheses indicates the year of last reapproval.
These factors include specimen preparation, apparatus, test conditions, methods of cleaning specimens, evaluation of results, and calculation and reporting of corrosion rates. The actual time of contact of the metal with the solution must also be taken into account. The mass loss during the test period can be used as the principal measure of corrosion.
t31 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. The procedures for determining these values are shown in detail in Test Methods E 8.
Active view current version of standard. A commercial surface may sometimes yield the most signi? A liquid atmospheric seal is required on the test vessel to prevent further contamination.
It is necessary to evaluate this localized corrosion separately from the overall mass loss. 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?
G axtm — 72 The values given in parentheses are for information only.
This can be accomplished by analysis of the solution after corrosion has occurred. 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 most common testing periods are 48 to h 2 to 7 days. The reporting of nonuniform corrosion is discussed below. It should be appreciated that pitting is a statistical phenomenon and that the incidence of pitting may be directly related to the area of metal exposed.
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. This guide also emphasizes the importance of recording all pertinent data and provides a checklist for reporting test data.
ASTM G Standard Practice for Laboratory Immersion Corrosion Testing of Metals_百度文库
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. This can be done by chemical treatment picklingelectrolytic removal, or by grinding with a coarse abrasive paper or cloth such as No.
With a thickness of approximately 3 mm 0. The amount of possible contamination can be estimated from the loss in mass of the specimen, with proper application of the expected relationships among 1 the area of corroding surface, 2 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. Consequently, tests run for long periods are considerably more realistic than those conducted for short durations.
If cleaning deposits for example, scouring powder remain or lack of complete dryness is suspected, then recleaning and drying is performed until a constant mass is attained. This practice, rather than a standardized procedure, is presented as a guide so that some of the pitfalls of such testing may be avoided.
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. 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.
In many such cases, corrosion rates are established by mass gain rather than mass loss.