I think the steel plate was at fault as well from what I have heard and
I beleive phosporus levels were an issue also. Much more is known about
the metallurgy now than in those days. I saw a program about the making
of one of these new super cruise liners in Norway IIRC and they went to
great lengths to make sure the steel quality was tightly controlled to
keep ductility reducing elements at very low levels for this reason.

Nick Hull wrote:

In article ,
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.


IIRC, the rivets on the Titanic became brittle in the 20 deg range
causing the ship to break up. The steel had too much sulphur.