BS EN ISO 7539-10:2020 pdf download.Corrosion of metals and alloys –Stress corrosion testing.
In the multiple immersion test, multiple sets of specimens are tested for different exposure periods. Cracks are detected by inspection after the immersion test. It can be useful to test a sufficient number of identical specimens for statistical evaluation at each exposure time. On test completion, the specimens shall be rinsed with distilled water or ethanol and dried. Destructive inspection can be applied to detect cracks. If required, a suitable cleaning method in accordance with ISO 8407 shall then be used to allow observation of possible cracks.
In the serial immersion test, specimens are repeatedly observed by non-destructive inspection after lapses of certain times until a crack is detected in the test. Before the inspection, the specimens shall be rinsed with distilled water or ethanol and then dried. The test time for a specimen is defined as the accumulated period over which the specimen is tested in a test environment. It can be useful to test a sufficient number of identical specimens for statistical evaluation. The serial immersion test is a more effective evaluation of the inspection time for crack detection with limited specimens than the multiple immersion test.
Generally, it takes time for the corrosion potential of specimens to return back to their previous potential in an environment after restarting the immersion test because oxide film on the specimens is transformed in the atmosphere. This can result in a crack-initiation time different from the immersion test without intermediate inspections. When the time to return back to the previous potential is so short that it can be negligible compared with the immersion test time, the serial immersion test can be carried out without considering the effect of intermediate inspections. A thin solid oxide film formed on surface of high corrosion resistant alloys such as alloys 600 and 690 is hardly transformed in the atmosphere after taking out from the environment. Additionally, the corrosion potential returns back to the previous potential after several hours in the environment, e.g. a simulated primary water environment (PWR).
8 Test report
The test report shall include the following information:
a) a full description of the test material, including chemical composition, heat treatment and
microstructural condition;
b) the International Standard used (including its year of publication);
c) tubing dimensions, specimen sizes and, if specimens were pre-strained, pre-strains;
d) a full description of the test environment;
e) the inspection procedure, including the type of microscope and magnification;
f) the time at which observations were made and when cracks became visible;
g) a description of the statistical methods used for the evaluation;
h) any deviations from the procedure;
i) any unusual features observed;
j) the starting and ending date of the test.BS EN ISO 7539-10 pdf download.