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.
|Published (Last):||24 May 2014|
|PDF File Size:||13.71 Mb|
|ePub File Size:||20.87 Mb|
|Price:||Free* [*Free Regsitration Required]|
Corrosion testing by its very nature precludes complete standardization.
Immersion Corrosion Testing According to ASTM G31 Standard
Masking may also be used to achieve the desired area ratios but may cause crevice corrosion problems. Proper ultrasonic procedures are an acceptable alternate. A liquid atmospheric seal is required on the test vessel to prevent further contamination. This standard does not purport to address all of the safety concerns, if any, associated with its use. In special cases for example, for aluminum and certain copper alloysa minimum of 24 h storage in a desiccator is recommended.
The values given in parentheses are for information only.
There are qstm number of other special types of phenomena of which one must be aware in the design and interpretation of corrosion tests. Careful observation is needed to ensure that pitting does not occur during cleaning. For relatively soft metals such as ast, magnesium, and copperscrubbing with abrasive powder is not always needed and can mar the surface of the specimen. Too much surface preparation may remove segregated elements, surface contamination, and so forth, and therefore not be representative.
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. A large surface-to-mass ratio and a small ratio of edge area to total area are desirable.
If cleaning deposits for example, scouring powder remain or lack g13 complete dryness is suspected, then recleaning and drying is performed until a constant mass is attained. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters. 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 statement must be quali? The suggested apparatus is basic and the apparatus is limited only by the judgment and ingenuity of the investigator. The phenomenon of forming a protective? It is the responsibility of the user of this standard to establish appropriate safety and qstm practices and determine the applicability astj regulatory limitations prior to use.
With borderline conditions, a prolonged test may be needed to permit breakdown of the passive? This can be accomplished by analysis of the solution after corrosion has occurred. These factors include specimen preparation, apparatus, test conditions, g1 of cleaning specimens, evaluation of results, and calculation and reporting of corrosion rates. For solutions corrosive to glass, suitable metallic or plastic kettles may be employed.
This practice also emphasizes the importance of recording all pertinent data and provides g311 checklist for reporting test data.
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. A metallographic examination may con?
Close attention and a more sophisticated evaluation than a simple mass loss measurement are required to detect this phenomenon. Preferably, the use of a re? Oxygen saturation is a function of the partial pressure of oxygen in the gas. Consequently, tests run for long periods are considerably more g1 than those conducted for short durations.
Methods for chemical cleaning after testing of speci? Duplicate strips of low-carbon steel, each 19 by 76 mm 3? If metallic contamination of the stamped area may in? The ast, time of contact of the metal with the solution must also be taken into account. This can be done by chemical treatment picklingelectrolytic removal, or by grinding with a asstm abrasive paper or cloth such as No. Where required, the exhausted constituents should be awtm or a fresh solution provided during the course of the test.
Localized corrosion is reported separately. 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?
For example, lead exposed to sulfuric acid corrodes at an extremely high rate at? 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.
Separate and special techniques are employed for the speci? However, the calculations must not be based on mass loss except in quali? 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.
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.
These factors include oxygen concentration, temperature, rate of?
The density in the constant K cancels out the density in the corrosion rate equation. The corrosion rate can be calculated from the concentration of the matrix metal found in the g311 and it can be compared to that determined from the mass loss of the specimens. The most common testing periods are 48 to h 2 to 7 days. Warning- Astmm 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 asm.
A commercial surface may sometimes yield the most signi? Originally approved in The use of towels for drying may introduce an error through contamination of the specimens with grease or lint. The procedures for determining these values are shown in detail in Test Methods E 8. Cupric ions may also exhibit a passivating effect upon stainless steel coupons exposed at the same time.