AFAIK, ferrite is magnetic and martensite will retain magnetism (hence
magnets made of hard steel).
If austenitic stainless does indeed form martensite on work hardening, that
would explain the increase in magnetism.

AFAIK, heating any 300 series stainless, quenched or not, will only
effectively anneal it, as with mild steel (correct me if I'm wrong).

Tim

--
"California is the breakfast state: fruits, nuts and flakes."
Website: http://webpages.charter.net/dawill/tmoranwms

"John" wrote in message
nk.net...
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.