Vacuum or air casting using induction hot topping

摘要

A method and apparatus for vacuum or air casting a molten superalloy, or other metal or alloy, containing an oxygen-reactive alloying element to form a cast part involves introducing the molten metallic material (melt) into a preheated mold having a melt reservoir, such as for example a mold pour cup, and gating for feeding the melt to one or more mold cavities. An induction coil disposed locally adjacent to the mold pour cup is energized in a manner to locally heat excess melt left in the melt reservoir to maintain it molten as the melt solidifies under vacuum or in air in the mold cavity to avoid shrinkage defects in the cast part.

主权项

1. A method of casting a molten metallic material, comprising:
providing an induction coil in fixed position beneath a crucible for containing the molten metallic material in a casting chamber where, in the casting chamber, the molten metallic material is discharged from the crucible into a mold to be cast, wherein the induction coil has an opening disposed beneath the crucible and has a coil height that extends only along a melt reservoir of the mold, moving the mold that is preheated outside of the casting chamber into the casting chamber to position only the melt reservoir associated with the preheated mold in the coil opening of the induction coil so that the induction coil extends only along the melt reservoir and is locally adjacent to the melt reservoir, leaving a region of the preheated mold including one or more mold cavities disposed beneath and outside of the induction coil in the casting chamber, discharging the molten metallic material from the crucible in the casting chamber through the coil opening into the melt reservoir to introduce molten metallic material into the preheated mold via the melt reservoir and gating that feeds the molten metallic material to the one or more mold cavities so as to completely fill the one or more mold cavities with the molten metallic material and provide excess molten metallic material in the melt reservoir and gating, and energizing the induction coil extending along only the melt reservoir and disposed locally adjacent to the melt reservoir in the casting chamber in a manner to locally heat the molten metallic material in the melt reservoir to maintain it molten as the molten metallic material solidifies in the one or more mold cavities of the preheated mold while the mold resides in the casting chamber.