ASTM G_Laboratory Immersion Corrosion Testing of Metals. August 18, | Author: Description. Designation: G 31 – 72 (Reapproved ). Buy ASTM G() Standard Practice for Laboratory Immersion Corrosion Testing of Metals from SAI Global. Offering ASTM G31 corrosion testing + modified tests to fit your needs and budget . Rapid, high-quality service by experts.
This guide also emphasizes the importance of recording all pertinent data and provides a checklist for reporting test data. 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. It should be appreciated that pitting is a statistical phenomenon and that the incidence of pitting may be directly related g31-722 the area of metal exposed.
However, the calculations must not be asm on mass loss except in qualification tests such as Practices Awhich is usually small but on microsections which show depth of attack.
It is imperative to note that this usually occurs with no significant loss in mass of the test coupon, although certain refractory metals are an exception to these observations. We are a non-profit group that run this website to share documents. The density in the constant K cancels out g1-72 density in the corrosion rate equation. If the influence of heat transfer effects is specifically of interest, specialized procedures in which the corrosion specimen serves as a heat transfer agent must be employed 1.
This statement must be qualified by stating that corrosion should not proceed to the point sstm the original specimen size or the asrm area is drastically reduced or where the metal is perforated.
These factors include oxygen concentration, temperature, rate of flow, pH value, composition, and other important characteristics of the solution.
A number in parentheses indicates the year of last reapproval. Excellent references for the use of statistics in corrosion studies include Ref.
ASTM G31 – 72() Standard Practice for Laboratory Immersion Corrosion Testing of Metals
G 31 — 72 Reapproved Standard Practice for Laboratory Immersion Corrosion Testing of Metals1 This standard is issued under the fixed designation G 31; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. Special coupons for ast, sections of welded tubing may be employed for specific purposes.
Current edition approved May 1, A large surface-to-mass ratio and a small ratio of edge area to total area are desirable. However, the absence of cracking should not be interpreted as indicating resistance see 4.
Close attention and a more sophisticated evaluation than a simple mass loss measurement are required to detect this phenomenon. Location of deposits, variations in types of deposits, or g31-772 in corrosion products are extremely important in evaluating localized corrosion, such as satm and concentration cell attack. The most common testing periods are 48 to h 2 to 7 days. For other degrees of aeration, the solution should be sparaged with air or synthetic mixtures of air or oxygen with an inert gas.
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. Most tests related to process equipment should be run with the natural atmosphere g31-772 in the process, such as the vapors of the boiling liquid.
Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. It is impractical to propose an inflexible standard laboratory corrosion testing procedure for general asgm, except for material qualification tests where standardization is required.
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. The others are used principally as a supplement to remove heavily encrusted corrosion products before scrubbing. These factors include specimen preparation, apparatus, test conditions, methods of cleaning specimens, evaluation of results, and calculation and reporting of corrosion rates.
ASTM NACE / ASTMG31 – 12a Standard Guide for Laboratory Immersion Corrosion Testing of Metals
Interpretation of Results After final preparation of the specimen surface, the specimens should be stored in a desiccator until exposure, if they are not used immediately. The degree of lateral spreading of pits may asm be noted. This standard, rather than a standardized procedure, is presented as a guide so that some of the pitfalls of such testing may be avoided.
A commercial surface may sometimes yield the most significant results.
ASTM G31-72_Laboratory Immersion Corrosion Testing of Metals
It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the g13-72 of regulatory limitations prior to use. 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.