Ring Specimen Indications
Minimum No. of
Test specimen(s) used with QQIs offer a more versatile means of checking system performance than afforded
by the Ketos ring. The specimens can be real parts or designed to be representative of the most challenging
inspection to be currently performed. This combination is capable of providing an adequate check on any
magnetic particle inspection system. Even though QQIs respond to the applied, not residual, field,
demagnetization is necessary of the specimen(s) in order to remove the previously applied inspection media.
The ultimate specimens for the performance tests are cracked parts. If available, they require careful
handling to remain corrosion-free and retain their f law sizes.
Amperage indicator accuracy check SHALL be performed using the calibrated ammeter/shunt authorized in
TA-455. Operation of the ammeter/shunt SHALL be according to the commercial manufacturers operating
instruction. DC amperage variations exceeding 10% at reading or +60 amperes, whichever is greater, and