Vacuum melting/casting method to reduce inclusions

In the melting of successive charges of a nickel, cobalt or iron base superalloy including one of Al and Cr as an alloying element in a melting vessel, a method of reducing inclusions in the melted charges attributable to the melting thereof, comprising successively melting the charges in the melting vessel under an inert gas partial pressure effective to reduce volatilization of said alloying element and condensation thereof on the melting vessel as one or more condensate deposits that, if present, could enter the melted charges and constitute inclusions in the resultant castings produced therefrom.

A method of melting of an alloy charge, comprising melting the charge in a melting vessel having a ceramic working surface for contacting the melt and establishing a gas partial pressure on the melted charge effective to reduce wetting of the melting vessel by the melted charge.

A method of melting successive nickel, cobalt, or iron base superalloy charges, comprising successively melting each superalloy charge in a melting vessel having a working ceramic surface for contacting the melted charges and establishing an inert gas partial pressure on each melted charge effective to reduce wetting of the melting vessel thereby.

In the melting of an alloy charge including a vaporizable alloyant in a melting vessel, a method of reducing inclusions in the melted alloy charge attributable to the melting thereof, comprising a) melting the charge in the melting vessel under a gas partial pressure effective to reduce volatilization of said alloyant and condensation thereof on the melting vessel as one or more condensate deposits that, if present, can enter the melted charge and constitute inclusions in a casting produced therefrom and b) reducing the gas partial pressure in the melting chamber prior to casting the melted charge from the melting vessel to reduce gas entrapment in said melted charge and thus in the casting produced therefrom.

In the melting of successive charges of a nickel, cobalt, or iron base superalloy including one of Al or Cr as an alloying element in a melting vessel, a method of reducing inclusions in the melted alloy charge attributable to the melting thereof, comprising a) successively melting the charges in the melting vessel under a gas partial pressure effective to reduce volatilization of said alloyant and condensation thereof on the melting vessel as one or more condensate deposits that, if present, can enter the melted charges and constitute inclusions in the resultant castings produced therefrom and b) reducing the gas partial pressure in the melting chamber prior to casting the melted charge from the melting vessel to reduce gas entrapment in said melted charge and thus in castings produced therefrom.

In the remelting of successive prealloyed metal alloy charges including a vaporizable alloyant in a melting vessel, a method of reducing inclusions in the melted charge attributable to the melting thereof, comprising a) successively melting the charges in the melting vessel under a gas partial pressure effective to reduce volatilization of said alloyant and condensation thereof on a pouring region of the melting vessel as one or more condensate deposits that, if present, can enter the melted charges and constitute inclusions in a casting produced therefrom and b) casting the melted charge over the pouring region of the melting vessel into a mold.

In the melting of successive charges of a nickel, cobalt, or iron base superalloy including one of Al or Cr as an alloying element in a melting vessel, a method of reducing inclusions in the melted alloy charge attributable to the melting thereof, comprising a) successively melting the charges in the melting vessel under a gas partial pressure effective to reduce volatilization of said alloyant and condensation thereof on a pouring region of the melting vessel as one or more condensate deposits that, if present, can enter the melted charges and constitute inclusions in the resultant castings produced therefrom and b) casting the melted charge over the pouring region of the melting vessel into a mold.