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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The phenomenon of forming a protective?
This standard, rather than a standardized procedure, is presented as a guide so that some of the pitfalls of such testing may be avoided. It is imperative to note aastm this usually occurs with no signi? A liquid atmospheric seal is required on the test vessel to prevent further contamination. Link to Active This link will always route to the current Active version of the standard. Too much surface preparation may remove segregated elements, surface contamination, and so forth, and therefore not be representative.
Preferably, the use of a re?
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. 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.
If this is a factor to be considered in a speci? Care should be used to avoid the removal of sound metal. It should be used as a reference to ensure that the test will allow generation of data relevant to the application with v31 minimum of interferences. A commercial surface may sometimes yield the most signi? If metallic contamination of the stamped area may in? 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.
The total surface area of a circular specimen is given by the following equation: Methods for chemical cleaning after testing astn speci?
For relatively soft metals such as aluminum, magnesium, and copperscrubbing with abrasive powder is not always needed and can mar the surface of the specimen. Corrosion testing by its very nature precludes complete standardization. Last previous edition approved in as G 31 — 72 Wstm agitation is required, the apparatus can be modi?
In many such cases, corrosion rates are established by mass gain rather than mass loss. The values given in parentheses are for information only. 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.
However, there are cases where this assumption is not valid. It is impractical to propose an in?
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.
Interpretation of Results Originally approved in With a thickness of approximately 3 mm 0. Methods of Cleaning Specimens after Test 9. A method of electrolytic cleaning is described in Practice G 1. It is impractical to propose an inflexible standard laboratory corrosion testing procedure for general use, except for material qualification tests where standardization is required.
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. Link to Active This link will always route to the current Active version of the standard.
The choice of a speci? ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard.
The most common testing periods are 48 to h 2 to 7 days. The coupling of corrosion coupons then yields only qualitative results, as a particular coupon re?
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. 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: 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.
It should be observed, however, that galvanic corrosion can be greatly affected by the area ratios of the respective metals, the distance between the metals and the resistivity of the electrolyte. These factors g311 oxygen concentration, temperature, rate of?
Immersion Corrosion Testing According to ASTM G31 Standard
It is necessary to evaluate this localized corrosion separately from the overall mass loss. These changes should be determined if possible. The use of towels for drying may introduce an error through contamination of the specimens with grease or lint.