On Wed, 23 Jun 2004 16:28:36 +0100, David Billington
wrote:

Hopefully someone with more detailed knowledge may chip in but what you
are interested in is the ductile-brittle transistion temperature for the
material. For common structural steels it is not much below freezing
IIRC from college days. Above this temperature failures exhibits ductile
behaviour and below it brittle behaviour but with a transition between
to two dependant on the material. IIRC this property can be an issue in
artic conditions. So I could speculate that freon on a carbon steel lock
may cool it sufficiently to make it brittle, but for alloy steel it may
not. IIRC stainless steel maintains its ductility to lower temperatures
than carbon steel.

snip

Yes, but if you fill the lock with water, and are able to freeze that,
you may destroy the lock in doing so. Water expands as it freezes, and
nothing, but nothing, will stop it. If it doesn't break the lock first
time, run some more water in and do it again.

Al Moore