I currently work as Maintenance in an Aluminum foundry that makes cast aluminum engine heads for a major car company. The process to come out with a good usable casting is pretty complex, especially on the scale that we do. We utilize steel dies to create the outside mold and a sand/chemical mixture to create the necessary voids. We use a with 5 60 amp heaters to keep the aluminum molten. and water to ensure the aluminum solidifies at the proper rate to ensure a solid casting. there's ALOT more that goes on and I can go into further detail if anyone needs but we strictly deal with aluminum, so I have no experience with steel, though I'm sure some of the process is the same, depending on the scale of the steel being cast.