A place I am no longer at went from SolidWorks to IronCAD back to SolidWorks. Since IronCAD is all but gone (I heard only 3,000 seats worldwide once) there is nothing that anyone writes to help with this. When I was there, there were three things we did.
a) exported to parasolid and brought in and used as a dumb solid
b) exported and used feature works to bring it back
c) re drew the part completely.
IronCAD is a piece of garbage. No one sells and supports it in my area anymore. You can't get local training. And no one local uses it either. It's a pile get rid of it and switch.