I've been aprofessional metalcaster for close to 25 years witha degree in metallurgy. Oxidation is least of your concerns when processing steel. Depending upon the composition, nitrogen is the biggest culprit.
You also use different molding materials for steel. Petrobond won't do. Kiln dried ceramic makes great mold and casting, all of that with it's own process restraints and problems.
You don't want to use graphite crucibles with steel, the molten metal dissolves the graphite in the crucible and you end up with a stainer.
You have to have steel in the 3050 degree F range to pour it and it looses heat really fast!!!! All the prep work and you end up with a mis run casting.
Commercial vacuum induction furnaces, especially with aerospace castigns and alloys, have the preheated ceramic mold on top of the induction furnace, at the proper time teh whole unit is inverted and the mold filled. |