distinguish SS316 from SS304

No.

To the best of my knowledge there are no simple tests as they are both austenitic non-magnetic stainless steels. The major difference is in the 2-3% molybdenum in the 316.

There are instruments on the market that can differentiate very quickly and accurately, but they are quite expensive. Texas Nuclear and Niton are two companies that I know but there must be many others. If memory serves, Niton has the advantage of an isotope of Americium (or something) which does not require replacing for basically the lifetime of the machine. This can be important if you live in a country where they or others are anal about all things nuclear.

Thanks for putting me straight on this one, did not know about this test. Looks great and a lot cheaper than my suggestion. I would guess it is not good enough for PMI, but would certainly solve this problem.

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