Methods for flow control in electroslag refining process

A method for controlling the flow of melt from a cold wall induction guide tube mechanism during electroslag refining comprising the steps of:

• providing a cold wall induction guide tube mechanism having a generally funnel shaped open interior adapted to receive and to dispense liquid metal as a stream from the lower neck portion thereof, the mechanism having at the lower end thereof a narrow gauge bottom pour spout having a central passageway defined by a plurality of individually water cooled fingers disposed to admit electric current to the passageway to produce a rapidly changing magnetic field at high flux density to generate a secondary current in metal within the passageway so as to selectively heat, cool and levitate said metal;
• providing induction coil means for selectively induction heating the funnel shaped interior of the tube mechanism;
• providing a reservoir of melt;
• providing a skull of melt in the funnel shaped cold wall induction guide tube mechanism;
• providing a flow of melt to and through the mechanism to form a stream of melt exiting the bottom pour spout of the mechanism;
• and
• selectively increasing or reducing the induction heating power supplied to the mechanism at a plurality of cycles per second in order to correspondingly selectively increase or reduce size of the central passageway bottom pour spout of the mechanism wherein the rate of flow of the melt therethrough is dynamically controlled.

A method for controlling the flow of melt from a cold wall induction guide tube mechanism during electroslag refining comprising the steps of:

• providing a cold wall induction guide tube mechanism having coolant flowing in the walls thereof;
• providing for controllable induction heating of the mechanism;
• providing a reservoir for the melt operatively positioned relative to the mechanism;
• providing a skull of melt in said cold wall induction guide tube mechanism;
• providing a flow of melt to and through the mechanism to form a stream exiting the mechanism;
• selectively increasing and reducing the induction heating provided to the mechanism for selectively increasing or reducing the temperature of the melt passing through the mechanism at a plurality of cycles per second to correspondingly vary the size of the skull in the mechanism, thereby dynamically controlling the rate of flow of the melt therethrough.

A method for controlling the flow of melt from a cold wall induction guide tube mechanism during electroslag refining comprising the steps of:

• providing a cold wall induction guide tube mechanism having a generally funnel shaped open interior for receiving and dispensing liquid metal as a stream from the neck portion thereof, the mechanism having a pour spout and a central passageway defined by a plurality of individually water cooled fingers operatively disposed to admit electric current to the passageway for producing a rapidly changing magnetic field for generating a secondary current in the metal within the passageway so as to selectively heat or cool the metal;
• providing induction coil means for induction heating of the mechanism;
• providing a reservoir of melt operatively positioned relative to the mechanism;
• providing a skull of melt in the mechanism;
• providing for flow of the melt to and through the mechanism forming a stream exiting the bottom of the mechanism;
• reducing the induction heating power supplied to the mechanism for selectively heating and cooling the melt passing through the mechanism;
• and
• selectively increasing and decreasing the cooling applied to the individually cooled fingers of the mechanism for selectively heating and cooling the molten metal within the passageway of the mechanism at a plurality of cycles per second to correspondingly dynamically vary the rate of the melt passing through the passageway.

A method for controlling the spray from an atomization zone for impacting a preform during the spray forming of the preform comprising the steps of:

• providing a cold wall induction guide tube mechanism including an orifice having a diameter;
• providing a reservoir of melt operatively connected to the mechanism;
• providing a stream of melt exiting the orifice;
• providing a skull of melt operatively formed in the cold wall induction guide tube mechanism;
• controlling size of the skull in the orifice such that the flow rate of the melt from the orifice is selectively varied;
• positioning means for forming a preform below the orifice;
• atomizing the melt into metal spray in an atomization zone;
• providing a substantially constant gas pressure to the atomizer;
• and
• selectively controlling gas-to-metal ratio in the atomization zone by varying said melt flow rate through said orifice at a plurality of cycles per second.

A method for controlling the spray from an atomization zone for impacting a preform during the spray forming of the preform comprising the steps of:

• providing an electroslag refining station;
• providing a cold hearth station having molten metal therein operatively positioned relative to the electroslag refining station;
• providing a cold hearth dispensing station including a cold finger orifice, operatively positioned relative to the cold hearth station, for dispensing the molten metal therefrom;
• providing a skull operatively formed in the cold hearth and the cold finger orifice;
• positioning induction coils proximate the cold finger orifice for providing heat;
• maintaining a hydrostatic head of molten metal above the cold finger orifice;
• regulating the heat transmitted from the coils to the cold finger orifice;
• regulating the hydrostatic head of molten metal above the cold finger orifice;
• controlling size of the skull in the orifice such that the flow rate of the melt from the orifice is selectively varied;
• positioning means for forming a preform below the orifice;
• converting the melt into metal spray in an atomization zone;
• providing gas at a substantially constant gas pressure to an atomizer;
• and
• selectively controlling gas-to-metal ratio in the atomization zone at a plurality of cycles per second.

A method of refining a metal ingot comprising:

• electroslag refining said ingot to produce a discharge stream of refined liquid metal;
• injecting an atomization gas to impinge said stream for spray forming a solidified deposit thereof on a billet;
• and
• dynamically varying discharge flow rate of said stream at a plurality of cycles per second relative to a flow rate of said atomization gas to correspondingly vary gas-to-metal ratio therebetween.