Probably. There's several requirements for oxy fuel cutting to work properly and cast irons don't meet them. Formation of refractory oxides are a common one i.e. you get oxides with a higher melting point than the material that interfer with the oxidation reaction
The pipe I was cutting was inside an enclosure where my sow Martha lives, and I didn't want sparks flying all over the place! At least with oxy cutting the sparks and dribbles are confined to a small area that I could keep her away from.
I had to cut through 5" of cast iron a couple of weeks ago. Unfortunately i couldn't so we changed the job to suit.
The reason it wouldn't work was that my supplier had got an order wrong and left me without a big enough cutting nozzle.
Apparently the technique is
1) an oversized nozzle compared with what you'd use for steel
2) lots and lots of preheat - way hotter than you'd do with steel
3) a carburising flame
4) a weaving action
Look up "flux cutting", where a steel rod is used between the flame and the target to be cut. The rod adds molten steel to the mix for more effective cutting. It's used in "scarfing torches" which have mechanisms fitted to feed the rod which is similar to gas welding rod or steel TIG filler. You can do it manually and it's referenced in the Linde handbooks.