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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Measurement of percent elongation is a useful index of embrittlement. Oxygen saturation is a function of the partial pressure of oxygen in the gas. A liquid atmospheric seal is required on the test vessel to prevent further contamination.
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. The corrosion rate can be calculated from the concentration of the matrix metal found in the solution and it zstm be compared to that determined from the mass loss of the atm. Any necessary distortion of the test conditions must be considered when interpreting the results. Care should be used to avoid the removal of sound metal.
Therefore, short tests on such materials would indicate a high corrosion rate and be completely misleading. If this is a factor to be considered in a speci? It may be desirable to test a g3 representative of the material and metallurgical conditions used in practice.
The density in the constant K cancels out the density in the corrosion rate equation. Active view current version of standard. Individual reprints asstm or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phonefaxor service astm. Masking may also be used to achieve the desired area ratios but may cause crevice corrosion problems. These factors include specimen preparation, apparatus, test conditions, methods of cleaning specimens, evaluation of results, and calculation and reporting of corrosion rates.
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. Interpretation of Results In practice, only alloys of the same general type should be exposed in the testing apparatus.
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
Chemicals are chosen for application to a speci? The values given in parentheses are for information only. The mass loss during the test period can be used as the principal measure of corrosion.
If there are any pits, the average and maximum depths of pits are determined with a pit gage or a calibrated microscope which can be focused? The values given in parentheses are for information only. There are a number of other special types of phenomena of which one must be aware in the design and interpretation of corrosion tests. 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.
NOTE 1—If desired, these constants may also be used to convert corrosion rates from one set of units to another. 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. Y31 references for the use of statistics in corrosion studies include Ref. These changes should be determined if possible.
Methods for chemical cleaning after testing of speci? Originally approved in However, the absence of cracking should not be interpreted as indicating resistance see 4. Circular specimens should preferably be cut from sheet and not bar stock, to minimize the exposed end grain. Duplicate strips of low-carbon steel, each 19 by 76 mm 3?
These factors include apparatus, sampling, test specimen, test conditions test solution composition, temperature, gas sparging, fluid motion, solution volume, method of supporting test 3g1, duration of testmethods of cleaning test specimens, interpretation of results, and calculation of corrosion rates. This standard does not purport to address all of the safety concerns, if any, associated with its use.
Last previous edition approved in as G 31 — 72 Careful observation is needed to ensure that pitting does not occur during cleaning. It is impractical to propose g3 inflexible standard laboratory corrosion testing procedure for general use, except for material qualification tests where standardization is required. In many such cases, corrosion rates are established by mass gain rather than mass loss. The degree of lateral spreading of pits may also be noted.
The choice of a speci? For other degrees asstm aeration, the solution should be sparaged with air or synthetic mixtures of air or oxygen with an inert gas. The use of towels for drying may introduce an error through contamination of the specimens with grease or lint. This practice also emphasizes the importance of recording all pertinent data and provides a checklist for reporting test data.
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. B31 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. Therefore, at least duplicate specimens should normally be exposed in each test.
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. Occasional exceptions, in which a qstm difference is observed, can occur under conditions of borderline passivity of metals or alloys that depend on a passive? If agitation is required, the apparatus can be modi?
Close attention and a more sophisticated evaluation than a simple mass loss measurement are required to ast this phenomenon.