Current edition approved May 1, Published May Originally approved in Last previous edition approved in as G 31 — 72 This practice, rather than a standardized pro- cedure, is presented as a guide so that some of the pitfalls of such testing may be avoided.
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More G An alternative method for similar purposes is Test Method G, which employs a cavitating liquid jet to produce erosion on a stationary specimen. The latter may be more suitable for materials not readily formed into a precisely shaped specimen.
The results of either, or any, cavitation erosion test should be used with caution; see 5. Test Method G73 describes another testing approach specifically intended for that type of environment. This is because the compliance of the coating on the specimen may reduce the severity of the liquid cavitation induced by its vibratory motion.
The result would not be representative of a field application, where the hydrodynamic generation of cavitation is independent of the coating.
In that method, the specimen is fixed within the liquid container, and the vibrating tip of the horn is placed in close proximity to it. While several investigators have used this approach see X4. The stationary specimen approach can also be used for brittle materials which can not be formed into a threaded specimen nor into a disc that can be cemented to a threaded specimen, as required for this test method see 7. However, adaptations of the basic method and apparatus have been used for such purposes see 9.
Guide G may be followed in order to determine the synergism between the mechanical and electrochemical effects. However, adherence to this test method in all other respects will permit a better understanding and correlation between the results of different investigators. See Section This must be considered in planning, conducting and reporting a test program. See also 7. For this reason, the consistency of results between different test methods or under different field conditions is not very good.
Small differences between two materials are probably not significant, and their relative ranking could well be reversed in another test. Scope 1. The vibration induces the formation and collapse of cavities in the liquid, and the collapsing cavities produce the damage to and erosion material loss of the specimen. The method therefore offers a small-scale, relatively simple and controllable test that can be used to compare the cavitation erosion resistance of different materials, to study in detail the nature and progress of damage in a given material, or—by varying some of the test conditions—to study the effect of test variables on the damage produced.
It permits deviations from some of these conditions if properly documented, that may be appropriate for some purposes. It gives guidance on setting up a suitable apparatus and covers test and reporting procedures and precautions to be taken. It also specifies standard reference materials that must be used to verify the operation of the facility and to define the normalized erosion resistance of other test materials.
The inch-pound units given in parentheses are for information only. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific safety warning information, see 6.
Our ASTM G31 1 Immersion Corrosion analysis applies to a wide range of conditions, allowing you to rapidly assess the corrosion rate of your materials and solutions. We run these tests over a wide range of temperatures and test parameters, and can tailor every test to meet your specific needs. Immersion corrosion evaluations using G31 provide a straightforward and simple method of determining the rate of corrosion in aqueous solutions. It is most appropriate for determine the corrosivity of liquids in static applications, but may also be used as an evaluation tool for many other applications. Testing is performed for periods from 24 hours to several months, depending on the alloy. As long as an appropriate evaluation time period is selected, G31 provide a good approximation of the long-term corrosion rate by general corrosion.
ASTM G31-72_Laboratory Immersion Corrosion Testing of Metals
Kitilar If this is a factor to be considered in a speci? Any necessary distortion of the test conditions must be considered g interpreting the results. Care should be used to avoid the removal of sound metal. The mass loss during the test period can be used as the principal measure of corrosion. Molarity and normality are also helpful in de?
ASTM G31 PDF
More G An alternative method for similar purposes is Test Method G, which employs a cavitating liquid jet to produce erosion on a stationary specimen. The latter may be more suitable for materials not readily formed into a precisely shaped specimen. The results of either, or any, cavitation erosion test should be used with caution; see 5.