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.
|Published (Last):||18 July 2004|
|PDF File Size:||17.34 Mb|
|ePub File Size:||10.62 Mb|
|Price:||Free* [*Free Regsitration Required]|
The choice of a specific treatment must be considered on the basis of the alloy to be tested and the reasons for testing. This can be accomplished by analysis of the solution after corrosion has occurred. 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.
For example, lead exposed to sulfuric acid corrodes at an extremely high rate at first, while building a protective film; then the rates decrease considerably so that further corrosion is negligible.
ASTM NACE / ASTMG31 – 12a Standard Guide for Laboratory Immersion Corrosion Testing of Metals
Link to Active This link will always route to the current Active version of the standard. Originally approved in Proper ultrasonic procedures are an acceptable alternate.
The mass loss during the test period can be used as the principal measure of corrosion. 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.
Please copy and paste this embed script to atm you want to embed Embed Script. There are a number of other special types of phenomena of which one must be aware in the design and interpretation of corrosion tests. Please fill this form, we will try to respond as soon as possible. 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.
For example, a small coupon is not as prone to exhibit pitting as a large one and it is possible aztm miss the phenomenon altogether in the corrosion testing of certain alloys, such as the AISI Type series stainless steels in chloride contaminated environments. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
The procedures for determining these values are shown in detail in Test Methods E 8. NOTE 1—The flask can be used as a versatile and convenient apparatus to conduct simple immersion tests.
Determination of Metal Corrosion Rate by ASTM G31-72. Canadian Laboratory
Consequently, tests run for long periods are considerably more realistic than those conducted for short durations. Warning- In many cases the corrosion product on the f31-72 metals titanium and zirconium is a hard and tightly bonded oxide that defies removal by asfm or ordinary mechanical means.
A liquid atmospheric seal is required on the test vessel to prevent further contamination. 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.
A metallographic examination may confirm the presence of stress-corrosion cracking. In special cases for example, for aluminum and certain copper alloysa minimum of 24 h storage in a desiccator is recommended. aetm
Cupric ions may also exhibit a passivating effect upon stainless steel coupons exposed at the same time. Methods of Cleaning Specimens after Test 9.
This practice also emphasizes the importance of recording all pertinent data and provides a checklist for g31-27 test data. Methods for chemical cleaning after testing of specific metals and alloys are described in Practice G 1. However, there are cases where this assumption is not valid.
If there are any g31-722, the average and maximum depths of pits are determined with a pit gage or a calibrated microscope which can be focused first on the edges and then on the bottoms of the pits.
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.
Masking may also be used to achieve the desired area ratios but may cause g31-27 corrosion problems. It is imperative to note that this usually occurs with no significant loss in mass of the test coupon, although certain refractory metals are t31-72 exception to these observations. 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 specific conditions of the test.
ASTM G31 – 72() Standard Practice for Laboratory Immersion Corrosion Testing of Metals
The degree of lateral spreading of pits may also be noted. Care should be used to avoid zstm removal of sound metal. Historical Version s – view previous versions of standard. Using the above units for T, A, Qstm, and D, the corrosion rate can be calculated in a variety of units with the following appropriate value of K: These ratios can be achieved through the use of square or circular specimens of minimum thickness.