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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B31 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. Proper ultrasonic procedures are an acceptable alternate. 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?
ASTM NACE / ASTMG31 – 12a Standard Guide for Laboratory Immersion Corrosion Testing of Metals
Active view current version of standard. This cannot be evaluated by mass loss alone. The mechanical property commonly used for comparison is the tensile strength.
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. Link to Active This link will always route to the current Active version of the standard. If this is a factor to be considered in a speci?
In special cases for example, for aluminum and certain copper alloysa minimum of 24 h storage in a desiccator is recommended. Last previous edition approved in as G 31 — 72 Originally approved in With a thickness of approximately 3 mm 0.
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 If agitation is required, the apparatus can be modi? 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.
Corrosion testing by its very nature precludes complete standardization.
ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. In many such cases, corrosion rates are established by mass gain rather than mass loss. For example, lead exposed to sulfuric acid corrodes at an extremely high rate at?
Scrubbing with a bristle brush and mild abrasive is the most popular of these methods. Most tests related to process equipment should be run with the natural atmosphere inherent in the process, such as the vapors of the boiling liquid. These factors include apparatus, sampling, test specimen, test conditions test solution composition, temperature, gas sparging, fluid motion, solution aetm, method of supporting test specimens, duration of testmethods of cleaning test specimens, interpretation of results, and calculation of corrosion rates.
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. It should be appreciated that aatm is a statistical phenomenon and that the incidence of pitting may be directly related to the area of metal exposed.
This standard, rather than a standardized procedure, is presented as a guide so that some of the pitfalls of such testing may be avoided. For solutions corrosive to glass, suitable metallic or plastic kettles may be employed.
A method of electrolytic cleaning is described in Practice G 1.
Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters.
Masking may also be used to achieve the desired area ratios but may cause crevice corrosion problems. The values given in parentheses are for information only. G331, some of the corrosion products usually adhere to the specimen as a scale and the corrosion rate calculated from the metal content in the solution is not always correct. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every?
Consequently, tests run for long periods are considerably more realistic than those conducted for short durations. Too much surface preparation may remove segregated elements, surface contamination, and so forth, and therefore not be representative. 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 sstm the chemical product with the corroding surface.
It is necessary to evaluate this localized corrosion separately from the overall mass loss. It is the responsibility atm 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. The choice of a speci? The most common testing periods are 48 to h 2 to 7 days. This resurfacing may cause some surface work hardening, to an extent which will be determined by the vigor of the surfacing operation, but is not ordinarily signi?
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. Warning—In many cases the corrosion product on the reactive metals titanium and zirconium is a hard and tightly bonded oxide that de? This practice also emphasizes the importance of recording all pertinent data and provides a checklist for reporting test data. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine ashm applicability of regulatory limitations prior to use.
The total surface area of a circular specimen is given by the following equation: This atsm must be quali? A large surface-to-mass ratio and a small ratio of edge area to total area are desirable.
Chemicals are chosen for application to a speci? Methods of Cleaning Specimens after Test 9. The others are used principally as a supplement to remove heavily encrusted corrosion products before scrubbing.