Check with a file to see if they are hard before you attempt to cut and weld. If they are hard you can still cut and weld, just need to be more careful. I think I would try sectioning with a plasma cutter or cutoff wheel, then TIG back together with quench plates on the ends so the ends stay hard but yet enough heat in the middle and moderate cooling rate to avoid cracking. Possibly use stainless filler rod.
I'm guessing they are hardened medium-high carbon steel. Anyone confirm this?
