just torch it,we cut/process everything with torches from cast to brass!

Plasma is the fastest but you can melt it with a regular demo torch. You just have to turn the oxygen up a bit. I put myself through a year and a half of college melting sheet off of tire curing racks (got the scars to prove it too :); just watch for spatter.

How about a small shear on a bobcat or mini excavator??
A demo saw with an appropriate blade. They are available in electric or gas.
They also make a handheld hydraulic shear, I can't remember who made them, but they are out there.

What I do know, is that every time we try something, the guys go back to using sawzall's.