General Electric Company

Steven A Miller

Milivoj Konstantin Brun

Lawrence E Szala

Marcus P Borom

Russell Scott Miller

David Paul Mourer

Paul Steven Svec

Roy W Christensen

Neil A Johnson

Mark Gilbert Benz

Michael F Gigliotti, Jr

Raymond Alan White

Peter G Frischmann

Thomas F Sawyer

Marcus Preston Boron

Lawrence A Wojcik

Close-coupled atomization methods employing non-axisymmetric fluid flow geometries have demonstrated superior efficiency in the production of fine superalloy powder, such as, for example, nickel base superalloys compared to conventional close-coupled atomization utilizing an axisymmetric gas orifice and an axisymmetric melt nozzle. It is believed that the principal physical mechanisms leading to non-axisymmetric atomization system fine powder yield improvement are atomization plume spreading, the at least lessening of the melt pinch down at the interaction point between the atomization liquid and the liquid melt and improved melt film formation at the melt guide tube tip. The greatest fine powder yield improvement occurred when the non-axisymmetric atomization systems are operated with atomization parameters that result in the formation of multiple atomization plumes. Recognition of the atomization plume characteristics ranging from pinch-down to spreading to multiple sub-plume formation provides a basis for atomization process control to provide the greatest fine powder yield improvement verses conventional close-coupled axisymmetric atomization systems.

Methods of close-coupled atomization of metals utilizing

Close-coupled atomization systems and methods employing axisymmetric fluid flow and non-axisymmetric melt guide tube exit orifice configuration have demonstrated superior efficiency in the production of fine superalloy powder, such as, for example, nickel base superalloys compared to conventional close-coupled atomization utilizing an axisymmetric annular gas orifice and an axisymmetric guide melt guide tube exit orifice configuration.

Close-coupled atomization utilizing non-axisymmetric melt flow

Close-coupled atomization systems and methods employing non-axisymmetric gas flow have demonstrated superior efficiency in the production of fine superalloy powder, compared to conventional close-coupled atomization utilizing an axisymmetric annular gas orifice and an axisymmetric melt nozzle. A means has been devised for convening otherwise axisymmetric plenums into non-axisymmetric plenums that produce non-axisymmetric gas flow.

Apparatus and method for converting axisymmetric gas flow plenums into

An apparatus and method for atomizing liquid metal are disclosed. A liquid metal supply is coupled to a nozzle for atomizing a stream of liquid metal in an atomizing zone extending from the nozzle. A viewing instrument provides a field of view extending to the atomization zone. A sensor coupled with the viewing instrument generates an image of the atomizing zone, and a control adjusts a flow rate of the stream responsive to the image.

Apparatus and method for atomizing liquid metal with viewing instrument

An apparatus, system and method for viewing an industrial process in an obscuring environment, such as molten metal atomization, is disclosed. An enclosure defining a chamber for containing a particulate form from atomized liquid metal has a nozzle for atomizing liquid metal mounted thereon in communication with the chamber whereby particles recirculate throughout the chamber. The nozzle being comprised of a cylindrical plenum means and a melt guide tube extending axially therethrough to an exit orifice. The plenum means is configured to provide a jet of atomizing gas converging in an atomizing zone extending from the exit orifice. A viewing means extends through the enclosure to a viewing orifice adjacent the atomization zone, the viewing means being configured to extend a field of view through the chamber to the atomization zone. A purging gas flow is provided in the viewing means to minimize atomized particles from contacting the window, and an image of the atomization zone is generated by viewing through the window.

Apparatus and method for viewing an industrial process such as a molten

A method for atomizing high temperature melts to achieve greater efficiency and smaller particle size is described. The method involves the employment of lower pressure gas coupled with an atomization nozzle larger than prior art structures. The atomization nozzle is part of a close coupled atomization structure having shallow depth dimension. The method allows atomization at melts with reduced likelihood of freeze off. The method reduces heat extraction from the melt while the melt is still contained in the atomization nozzle.

Atomization with low atomizing gas pressure

Apparatus for close coupled atomization of melts of metals having high melting points with low superheats is taught. The atomization apparatus includes means for supplying melt to be atomized at the relatively low superheat, melt guide means for guiding the melt as a stream to an atomization zone and a gas supply and means for delivering the gas as a stream to the atomization zone where both the melt supply and gas supply to the atomization zone are in very close proximity. The melt supply has an inwardly tapered lower end disposed immediately above the atomization zone. The gas supply surrounds the melt guide tube and the gas is delivered as a jet against the melt emerging from the melt guide tube. The temperature of the gas impacting the end of the melt guide tube is very low because of the gas expansion. The tendency for this gas to withdraw heat from the melt guide tube and cause a freeze-up is reduced by providing a shield for guiding the gas from the gas supply to the orifice where most of the gas expansion and cooling takes place. The gas shield contacts the melt supply tube at its lower end and conducts heat from the melt supply tube toward its upper end. The gas shield is kept very thin, and at least one groove is formed laterally in the gas shield to inhibit and reduce the flow of heat from the lower portion to the upper portion of the gas shield.

Gas shield for atomization with reduced heat flux

A method for improved atomization of molten metal having a melting point above 1000.degree. C. is taught. The atomization is carried out in close coupled atomizer. The melt to be atomized is supplied from a reservoir where it is heated to a temperature slightly above the melting point. The molten metal from the reservoir is guided to the atomization zone by a ceramic melt guide tube. The atomization is accomplished with the aid of a shallow draft atomizing nozzle. The melt in the melt guide tube is heated with the aid of an induction coil which is disposed thereabout and between the reservoir and the shallow draft gas nozzle.

Integral induction heating of close coupled nozzle

A method and apparatus for atomizing liquid metal are disclosed. A vessel supplies liquid metal through a pouring channel to an atomizing nozzle. A flow sensor provides at least one gas flow into the liquid metal, and determines a pressure difference from the gas flow. A processor determines the liquid metal flow rate through the nozzle from the pressure difference. A control adjusts the liquid metal flow rate in response to the determined liquid metal flow rate, and the liquid metal is atomized.

Method for atomizing liquid metal utilizing liquid flow rate sensor

The method and apparatus of this invention is related to measuring a flow rate of a liquid having a density .rho. from a vessel having an inner cavity and a pouring channel. A flow sensor introduces a first gas flow into the liquid in the cavity at a first position, the inner cavity having a cross-sectional area A.sub.1 at the first position, and a second gas flow into the liquid in the pouring channel at a second position, the pouring channel having a cross-sectional area A.sub.2 at the second position, there being a vertical distance z between the first and second positions. A transducer provides an output signal proportional to a pressure differential p.sub.1 -p.sub.2 between the first and second gas flows. A processor receives the output signal and determines the liquid flow rate m through the pouring channel according to the proportional relation ##EQU1## where g is gravity.

Apparatus and method for measuring the mass flow rate of liquid from a

A method of atomization of refined metal is taught. The method starts with the introduction of unrefined metal into an electroslag refining process in which the unrefined metal is first melted at the upper surface of the refining slag. The molten metal in the form of droplets is refined as it passes through the molten slag. The refined metal droplets are collected in a cold hearth apparatus having a skull of refined metal formed on the surface of the cold hearth and protecting the cold hearth from the leaching action of the refined molten metal. A cold finger bottom pour spout is formed at the bottom of the cold hearth to permit dispensing of molten refined metal from the cold hearth. The rate of flow of molten metal through the cold finger apparatus is controlled principally by controlling the rate of melting of the unrefined metal. The metal flowing from the cold finger apparatus is introduced to the upper end of a ceramic melt guide tube. Liquid metal emerging from the lower end of the melt guide tube is atomized by a gas orifice closely coupled to the lower end of the melt guide tube.

Atomization of electroslag refined metal

A nozzle for atomizing molten metal to provide a powder having improved yield of fine particles is disclosed. The nozzle is comprised of a gas plenum, a melt delivery tube, and an annular inner wall means within the gas plenum for delivering atomizing gas to the exit orifice of the melt delivery tube. The exit orifice of the melt delivery tube has a ratio of inside diameter to outside diameter that provides a reduced flow of liquid through the tube during atomization.

Method and apparatus for atomizing molten metal

An apparatus for viewing the atomization of liquid metal is disclosed. A nozzle for atomizing liquid metal having a cylindrical plenum, and a melt guide tube extending axially therethrough to a melt exit orifice. The plenum defines an inner chamber coupled with an atomizing gas orifice spaced from the exit orifice and configured to provide an annular jet of atomizing gas converging in an atomizing zone extending below the exit orifice The plenum having an inner sidewall and an outer sidewall defining the inner chamber therebetween. The inner sidewall extends below the exit orifice so that the inner sidewall is spaced from the atomizing zone. A cylindrical sleeve extends through the outer sidewall to a first end in the inner chamber. A camera mounted in the sleeve has a field of view extending from the first end. A transparent window is mounted to seal the first end. The sleeve is positioned so the field of view extends through the atomization zone. A porthole extends through the inner sidewall along the field of view to provide a view of the atomization zone to the camera, and for a gas flow therefrom.

Liquid metal atomization nozzle with integral viewing system

A transfer tube is produced comprised of a high density ceramic oxide tube having directly bonded to its outer surface wall a low density ceramic oxide shell.

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Amsterdam, NY, United States of America

Steven A Miller