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 application.
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 accordance
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 efficient
cleaning with ethanol and cloth until no contaminations are
visible
is sufficient.