QQI
Quantitative Quality Indicators
QQI – Quantitative Quality Indicators are magnetic particle test-pieces with artificial defects. They are able to show that the technique is effective in all directions. QQIs provide a guide to the magnitude and direction of the tangential field strength, but the magnetic particle inspection (MPI) standard (BS EN ISO 9934-1:2016) states they should not be used to verify that the field strength is acceptable. However, it goes on to say that, in the absence of a representative part containing either natural or artificial discontinuities, QQIs can be used to provide an overall test of the performance of the procedure, magnetisation technique and detection media. Hence, they are a valuable tool for developing a magnetic particle procedure.
QQIs are thin and able to conform to the geometry of the test-piece. They must be held in intimate contact with the test-piece by either tape or glue.
For information on QQI, see:
www.nde-ed.org/NDETechniques/MagParticle/Equipment/FieldIndicators.xhtml
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