It can possibly be welded by a good man with a TIG kit
The two risk factors are
1) oil, carbon and dirt - getting it clean enough to weld may not be possible if polutants have soaked into the surface esp where the thread was cut
2) porosity and disolved gas in the casting - only really likely if it was die-cast
If you can bolt the flat mating surface to a solid plate to avoid warp and give it to a good welder?
So it depends on the price of a second hand one i suppose