11.4 Ageing
In order to verify whether ageing at high temperature has a deleterious effect, THERMAL-LINKS shall be
subjected to the following series of test steps. The temperature shall be maintained constant within ±1 K.
Any specimen remaining intact at the conclusion of each step shall be submitted to the next step.
Conformity shall be considered satisfactory if all specimens have functioned after the first two steps:
Step 1 If requested by the manufacturer, the specimens are subjected to a temperature chosen
between Tf – 15 K and Th for a period of three weeks. At the conclusion of the test, at least
50% of the specimens shall not have functioned.
The following tests are mandatory:
Step 2 Tf – 15 K for three weeks. At the conclusion of the test, at least 50% of the specimens
shall not have functioned unless the specimens have already been submitted to Step 1, in
which case all specimens may have functioned.
Step 3 Tf – 10 K for two weeks.
Step 4 Tf – 5 K for one week.
Step 5 Tf – 3 K for one week.
Step 6 Tf + 3 K for 24 hours.
The specimens shall then cool in the test chamber to less than Tf – 35 K.
The test is considered successful if all specimens have functioned.