I am not an NDE technicain, but at one time did have a low-level certification in NDE/NDT. I have taken courses on it and managed NDE folks in several countries, so I have seen a lot of it "up close and personal."
one little pet peave-people involved in NDE/NDT (non-destructive evaluation/non-destructive testing) never use the term "magnaflux." At least I have never met one who did. Instead they refer to "mag-particle testing," usually just called "mag particle" or they say they will "mag" a part. It is kinda like calling a Parker a Fox. Minor pet peave.
What NDE shows you is an "indication," not a crack. A good magparticle technician can examine a set of barrels and find abnormal indications, usually indicationd a "crack," "slag inclusion," and whatnot. They can also give you a qualified opnion on how likely the indication is to cause problems later on. They can find these inside the wall of the tubes, not just on the surface. If it were me and I wanted some testing to give me a warm and fuzzy about my tubes, I would "wet mag" the barrels and be happy with that. In this case, you acutally use a liquid that holds suspended paricles. I would also use the liquid requireing a black light to see the florescent indications. I think this would give the best of finding menaingful indications in the tubes for the least cash outlay. Most "bang for oyur buck," if you will.
If all you are worried about is surface indications, then a good visual inspection or PT (dye-penetrant testing, or "dye checking") will reveal indications quite nicely, quickly, and cheaply. Without going into detail, there are several different ways to MT and PT.
Also, a good technician can find an amazing amount of indications from a straight visual inspection. They do it every week of the year and can find things I sure can't always see, and I consider myself to be above average at finding indications.
One thing I have not seen here is UT, or "ultrasonic testing. And no, we are not checking to see if your damascus tubes are knocked up!!! A good UT technican can tell you loads of information about the indications. UT, especialy "shear wave," makes my brain hurt and eyes cross. you need a very experienced technician to perform this test. But a good one can tell you a lot about your tubes and any indications they may have. The hard part here is finding a technician with a lot of UT experience who you trust. A relatively small number of them in the NDE world.
And there is nothing wrong with good ole' RT, or x-ray. Yes, there will be tons of lines on the film due to all of the welds, but again, a good technician can find indications there.
If you are really worried about the integriy of your tubes and will spend some cash to be warm and fuzzy, RT them and UT them if RT shows an indication that worries you.
Of course, the easiet way to check the tubes is to have the gun proof tested in good proof house. Remember, a pressure test ALWAYS supercedes any NDE/NET findings. Basically, the "proof is in the pudding," or in this case "the pudding is in the proffing!"
