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Can anybody out there give me the industry standard, procedure, info about test equipment or any info for ferritoscope test for alloy steel welds. (I thing this test is for metallurgical measurement for ferrite rate in the material)
Here is a string to Fisher Technolgies. The manufacturer of the Fisher Ferritscope. Hope this helps.
We use a ferritiscope here where I work. The particalar model that we have gives readings in % ferrite, and FN. But, as some say, no one really knows for sure if the % ferrite readings are right or not. In general, and in welding specifically, although it is not related directly to percentages of microstructures, FN is the more usefull number (in my opinion). It also seems to me (just my impression) that the magnegage is the more commonly used instrument. There have been several good articles in the Welding Journal over the last few years about the development of standards for ferrite measurement, the accuracy of FN and percent ferrite determinatin, etc. I believe that the most recent one would be the April 2001, and several in 2000/1999.
I am also assuming that when you say alloy steels, that you mean high alloy steels that have enough alloy to form at least part austenite, or not too high alloy so that they form at least some ferrite, as those are the steels that the instruments are good for. The other challenge when using your instrument related to the FN of the particular steel you are testing, is you need to have the right calibration samples if you want an accurate reading. I do not think it is too hard to get a set of samples that would compare to 316 weld metal for instace which might get something like an 8 FN. You would need another set of calibration samples for duplex sst though, as thier FN can range quite extensively from the high 20s to the 70s.
I don't know if this answers any of your questions, or raises more, but hopefully it might steer you in the right direction for answers.
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