"Tim Williams" wrote in message
...
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

When you work-harden 300 Series stainless, some austenite is converted to
martensite. This is what makes work-hardened 300 Series slightly magnetic.

There are special, modified versions of some common 300 Series stainess
steels that are formulated specifically to prevent them from becoming
magnetic upon work-hardening. These are intended primarily for wire-drawing,
where the reduction in section is extreme and the resulting magnetism can be
a problem in some applications. These special grades get their non-magnetic
properties from very small additions of copper to the alloy.

Heat treating 300 Series stainless, in general, will do nothing but anneal
it. There are some minor exceptions that you can read about with a Google
search. You won't get significant hardening with *any* 300 Series grade from
heat treating, however.

The easiest way to tell if a steel drum is stainless is by testing it with a
magnet. Any carbon steel and any common alloy steel that might be used for
making drums will be very magnetic. No stainless used to make a drum will be
more than very slightly magnetic. There's no mistaking the difference.

--
Ed Huntress