The results of the investigations show that the PT application
on components for use under vacuum conditions can in general be
allowed. The following details should be adhered to:
The test surface should have a simple geometry. In no case they
should have gaps or holes, in which the penetrant can get.
Vacuum boundary welds have to be leak tested before PT appli-
cation. So there is no risk of subsequent leaks which are blocked by
the PT medium before.
With PT detached small indications, that are acceptable in accor-
dance to established rules (e.g. DIN EN 23277, allowable limit 1
or AD2000 HP 5/3) could be left. Larger indications, which could
include a sizeable portion of penetrant, should be grinded and
repaired.
An efficient cleaning after PT is necessary. But obviously an effi-
cient cleaning with ethanol and cloth until no contaminations are
visible is sufficient.