"Dan White" wrote in message
...
"spiral_72" wrote in message
oups.com...
Actually, yea..... I thought about that. I really don't know what to
expect. I would suppose a material could be brought to a low enough
temp causing that material to become brittle. Water, plastic, chewing
gum, lots of stuff becomes brittle at a low enough temp. Any idea what
that temp is for steel?

I haven't looked that up -- maybe it can be found by googling. It
probably
depends on the type of steel, although they might all be in the same
neighborhood. I checked on dry ice the other day and I think it sublimes
at -78.5 deg C at atmospheric pressure, and warmer at higher pressure, but
you'd need an equilibrium diagram for that. -78.5 C should be the worst
case though.

dwhite


Dodge the whole embrittlement problem by putting down a layer of 1/4" - 1"
thick styrofoam between the dry-ice and the base of the tank. It should not
affect the volume capacity significantly, but it will keep the steel at a
reasonable temperature. It will slow down your melt rate quite a bit, but
that's probably not a bad thing anyways.

You could use a ceramic or hard plastic insulator too, but I'd be concerned
about the additional shrapnel when the tank explodes ;-)

Joe