Howmet Research Corporation

Donald L Bierstine

Christine M Stabile

Donald E Larsen, Jr

Russell G Vogt

John R Mihalisin

Jeffery S Smith

Jeffrey D Irvine

Robert L Larsen

Gail R Cole

Thomas W Nielsen

John P Kunkle

Richard A Biondi

A solid charge of metal or alloy is placing in a crucible melting chamber defined by a monolithic refractory tubular sleeve disposed on a water cooled metallic base, an energizing induction coil disposed about the sleeve to inductively heat the solid charge to a molten state in the melting chamber including forming a skull of solidified metal or alloy on inner surfaces of the sleeve and base to confine the molten charge, and removing the molten charge from the melting chamber, leaving the skull in place on the inner surfaces of the sleeve and base. The crucible can be reused in melting another solid charge of metal or alloy after the molten charge is removed.

Hybrid induction skull melting

Directionally solidified superalloy components having a bulk sulfur concentration of less than 1 part per million by weight are provided by vacuum melting a charge to form a superalloy melt, desulfurizing the melt by contact with a calcium-bearing desulfurizing agent for a time to reduce sulfur concentration of the melt to less than 1 ppm by weight, casting the melt directly or following solidification and remelting in a ceramic investment mold, and directionally solidifying the melt as cast components without adverse bulk sulfur pick-up subsequent to desulfurization to provide castings having a sulfur content below 1 ppm, such as in the range of hundreds of parts per billion to provide significantly improved oxidation resistance.

Ultra low sulfur superalloy castings and method of making

Growing community of inventors

Newton, NJ, United States of America

Donald L Bierstine