Why not use a CAST rod to weld cast, no reason you can't, this is how I modded my front pulley when welding a steel trigger wheel onto it.
That said the heat will affect it, not likely in long term to last unless you use a LUMIWELD rod, the stuff is simply amazing, don't even need a welding set!!, just the rod and a heat source, eg blowtorch will do it, works on pretty much all metals.
tabetha