LPI Dwell Times

lpi, liquid penetrant inspection

How many times have you looked for an easy number to remember regarding a minimum or maximum time for penetrant and/or developers. 

Well here it is:

According to ASTM E-165, fluorescent and visible penetrants within ambient temperature ranges (50 to 100 F) are similar enough to say:

Penetrant Dwell times of 5 minutes (for all but wrought, forgings, plate, then it is 10 minutes 8.5.2)

Developer Dwell times of 10 minutes (after drying, 8.8.6)

Simple enough!!! But don't forget outside the normal temperature range, longer dwell times for both may apply.

This is a general rule of thumb, as the classrooms teach 10 to 30 minutes (temp's applied).


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