You "could" replace it for cheap. Do you have any access to the part? What I mean is, do you know of anyone who might have that size SS wire? Depending on the size, I could send you a piece of SS or, Inconel or, Titanium. I will just cut you a piece or two of our filler wire for welding.
I doubt I will have the exact size but, I fixed my cascade HOB this way. The new shaft is just a touch smaller in diameter then the old one. No issues though.