IF you have a central conducter rod and a 44 foot of 4 1/2 .250 wall casing pipe how can you check the senativity of mag particle inspection being done on it beside a castrol strip. I have had several differnt people say it cant be done
15:34 Nov-12-2009 Jim Draper Consultant, ASNT Level III MT PT RT VT Draper NDT, USA, Joined Jul 2009 99
Re: Mag Particle and Senativity check In Reply to Paul Skidmore at 14:51 Nov-12-2009 (Opening).
You could also use a QQI. It is a thin piece of metal with grooves in it. There is one with three circles cut into it, each circle a different depth. That would work. You could also use a hall effect gauss meter to verify the magnetic flux density on the surface of the pipe. It should be between 30 and 60 gauss. Or, if you have a piece of the pipe with a known discontinuity of the type you will be looking for, you could use that to prove the sensitivity of the test.
Go to the side of ASNT at look there for the technian V8NO2 , it explain well how to chek should be done ba the castrol strip.
Since you have a radial field in the pipe ,there is hardly ay field outside of the pipe.
Easiest way with the strip is to grind a small gouge inthe pipe.
Anyway if you inspect casing acc to API ,there is a recomandation for the minimum cd amperagedepende of the weight of pipe and unit used.