I know that after machining SS the heat creates a martensitic structure that
does not allow for magnetic alignment. so I believe that once heated and
immediately quenched ( maybe with compressed air) SS will have no attraction
to magnet. Regular carbon steel will still maintain some magnetism.

Open to correction


"Stratis" wrote in message
...
I've acquired three 50 gallon steel drums which I think were used in hot
water systems.

I need to know whether or not they are stainless steel (as opposed to
non-stainless). How can I test them?

Stratis.