A VERY cheap source for strong neodymium. (I have bought from them, and they are both reliable and fast.)
eBay Store - magnets: wind turbine, flexible magnets windmill blades, rare earth magnet
Neos (Neodymium rare earth) are really good, as a small fifty pound pull sucker (1" diameter by 1/2" grade N50 ) can be used at a distance to tell if steel has gone non-magnetic, without the hot steel being close enough to really damage the magnet. Just don't try to touch the steel to the magnet..... even with cold steel. These are POWERFULL.
No, I have no connection other than being a happy customer of theirs....
Paul Andrulis