I like to post about my experience to warn other that may attempt simullar things.
I need to add weld some angle iron pieces as spacers or retainers in a non critical application, any metal angle pice would have worked just fine , I did not want to waste fresh angle irons (mild steel,) so I reached for some bed frames I picked up for free a while back , for this kind of purpose.
I ended up cutting the hot rivets of with a plasma cutter , also making some minor cuts. and holes with it.
than I had to cut nice 1.5" pieces so I used a wet- horizantal bend saw. all went fine , cut a couple pieces, than came the throuble
I've noticed that the saw has been cutting the same piece for a fairly long time. ..... it actually got stopped right where one of the plasma cut whole was. the band saw arm would not budge, I thought it was stuck on something , So I applied light pressure to it. still nothing.
I flipped the piece around and started cutting it from the other side of the angle piece, again it was cutting fine till it reached the whole which was plasma cut, got stuck again.
conclusion, on the spot where the plasma cut was made on the bed frame , the metal got extremely hard , a regular blade would not cut it.
actually the blade got ruined. lesson learned.