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):||7 May 2004|
|PDF File Size:||15.55 Mb|
|ePub File Size:||7.32 Mb|
|Price:||Free* [*Free Regsitration Required]|
This practice also emphasizes the importance of recording all pertinent data and provides a checklist for reporting test data.
ASTM NACE / ASTMG31 – 12a Standard Guide for Laboratory Immersion Corrosion Testing of Metals
Any necessary distortion of the test conditions must be considered when interpreting the results. For proper interpretation of the results obtained, the speci?
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. A liquid atmospheric seal is required on the test vessel to prevent further contamination. It is the responsibility of the user of aastm standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations zstm to use.
With borderline conditions, a prolonged test may be needed to permit breakdown of the passive?
Scrubbing with a bristle brush and mild abrasive is the most popular of these methods. The choice of a speci? Solvents such as acetone, carbon tetrachloride, and alcohol are used to sstm oil, grease, or resin and are usually applied prior to other methods of cleaning. Measurement of percent elongation is a useful index of embrittlement. This statement must be quali?
Immersion Corrosion Testing According to ASTM G31 Standard
A method of electrolytic cleaning is described in Practice G 1. NOTE 1—If desired, these constants may also be used to convert corrosion rates from one set of units to another. The degree of lateral spreading of pits may also be noted. The mechanical property commonly used for comparison is the tensile strength. 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.
This standard does not purport to address all of the safety concerns, if any, associated with its use. 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?
The most common testing periods are 48 to h 2 to 7 days. Too much surface preparation may remove segregated elements, surface contamination, and so forth, and therefore not be representative. Care should be used to avoid the removal of sound metal. 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 this is a factor to be considered in a speci? Excellent references for the use of statistics in corrosion studies include Ref. Therefore, short tests on such materials would indicate a high corrosion rate and be completely misleading.
Masking may also be used to achieve the desired area ratios but may cause crevice corrosion problems. Last previous edition approved in as G 31 — 72 If clad alloy specimens are to be used, special attention must be given to ensure that excessive metal is not removed.
These ashm include specimen preparation, asm, test conditions, methods of cleaning specimens, evaluation of results, zstm calculation and reporting of corrosion rates.
This cannot be evaluated by mass loss alone. 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. Where required, the exhausted constituents should be added or a fresh solution provided during the course of the test. The total surface area of a circular specimen is given by the following equation: Chemicals are chosen for application to a speci?
A metallographic examination may con? Proper ultrasonic procedures are an acceptable alternate. The values given in parentheses are for information only. Corrosion testing by its very nature precludes complete standardization. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.
If metallic contamination of the stamped area may in? If agitation is required, the apparatus can be modi? The density in the constant K cancels out the density in the corrosion rate equation. Molarity and normality are also helpful in de? The values given in parentheses are for information only. Oxygen saturation is a function of the partial pressure of oxygen in the gas. These factors include oxygen concentration, temperature, rate of? 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.
A number in parentheses indicates the year of last reapproval. 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.
The coupling of corrosion coupons then yields only qualitative results, as a particular coupon re? In many such cases, corrosion rates are established by mass gain rather than mass loss.
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.
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