2.2. Application of the PT and test results
The samples were PT tested according to DIN EN 571-1 [2] (test
medium system IICd). The time for penetration and processing was
in each case 30 min. The test results are listed in Table 1.
2.3. Testing medium
The Helling’s Nordtest series was used as PT testing medium.
This series consists ofthe penetrant U88, cleaner U87 and developer
U89. The detailed composition of the medium was not available
from the company. Only the information of the material safety data
sheets [3] is available. According to this the penetrant consists of
fatty acid ester (hydrocarbon) and the diazo dye Solvent Red 164
(a compound of hydrocarbon and nitrogen). The cleaner medium
consists of ethanol and the developer consists of a suspension of
inorganic solids in ethanol. Cleaner and developer are in an aerosol
(injecting fluid: propane and butane). Only the penetrant is criti-
cal for the contamination of component parts because of its high
penetrating property (Fig. 2).