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Hi Sean.
You make a lot of sense and good points. Oh well,
it was just a conceptual idea anyway.
I guess if it was a good method to use, it would
already be in use. Just another crazy idea of mine.
Bill Akins.
----- Original Message -----
Sent: Tuesday, April 11, 2006 5:36
PM
Subject: Re: [PSUBS-MAILIST] Brass vs.
Bronze
While certainly possible, I think that there are a few
practical
limitations to casting a submarine hull. The obvious one
is size - you
need to cast the entire thing in one continuous pour,
necessitating a
foundry with that melt capacity. The second is
quality control -
porosity is much more difficult to avoid in casting than
it is in weld
beads - once cast, every square inch of the hull would need
to be
examined through non-destructive testing (x-ray, ultrasound, etc.),
as
opposed to just weld seams, and then if you do find a problem, you may
have to scrap the whole thing and re-cast if it is not in an area that
is easily patchable. The third is dimensional control - save for the
ideal case where you cast a perfect cylinder with no hull penetrations,
bosses, stiffeners, etc., variable cooling rates due to material
distribution within the cast will cause the finished casting to deviate
from the original pattern. Ordinarily, foundries will account for
this
by modifying the pattern to compensate (guesstimating), or by working
the finished castings in presses, etc. to bump them back into
compliance. For commonly cast parts like pump housings, etc., this
is
no big deal, but pressure vessels are somewhat more dependent on their
geometry for proper function. This is not to say that it couldn't be
done, but my gut instinct is that it would be cost prohibitive, as well
as a lot of work.
-Sean
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