Aluminum Company of America

Alcoa Inc.

Ho Yu

Robert A Ramser

John E Jacoby

Alvaro Giron

Men Glenn Chu

Daniel K Ai

David D Leon

Daniel E Hunter

Jeffrey J Shaw

Jeffrey A Nicol

Ken Kallaher

Douglas A Granger

S John Pien

Richard C Stiffler

Donald L Stewart

Francis J Glogowski

Kenneth Joseph Kallaher

Allen M Hummel

Judith G Stevens

William A Casada

Michael Scherbak

Carl R Reagin

Rick D Perdue

Raymond T Richter

Douglas L Bruce

Kenneth Kallaher

Molten metal is injected uniformly into a horizontal mold from a feed chamber in a horizontal or vertical direction at a controlled rate, directly on top of the metal already within the mold. A cooling medium is applied to the bottom surface of the mold, with the type and flow rate of the cooling medium being varied to produce a controlled cooling rate throughout the casting process. The rate of introduction of molten metal and the flow rate of the cooling medium are both controlled to produce a relatively uniform solidification rate within the mold, thereby producing a uniform microstructure throughout the casting, and low stresses throughout the casting. A multiple layer ingot product is also provided comprising a base alloy layer and at least a first additional alloy layer, the two layers having different alloy compositions, where the first additional alloy layer is bonded directly to the base alloy layer by applying the first additional alloy in the molten state to the surface of the base alloy while the surface temperature of the base alloy is lower than the liquidus temperature and greater than eutectic temperature of the base alloy &#x2212;50 degrees Celsuis.

Method of unidirectional solidification of castings and associated apparatus

A scrap melter for light gage metal scrap includes a shrouded impeller connected to a shaft, the shaft connected to a rotary power device. The shrouded impeller is immersed in a molten metal pool in a charge bay or furnace. It is inclined at an angle relative to the vertical. The shrouded impeller creates a vortex in the molten metal pool, which includes a whirlpool at the surface of the molten metal. The center of the whirlpool is horizontally displaced from the shaft so that scrap can be charged into the whirlpool to be ingested into the vortex. The shrouded impeller creates a vortex for scrap ingestion and pumps molten metal for re-circulation through the melting system without the need of a separate pump.

Controlled free vortex scrap ingester and molten metal pump

Molten metal is injected uniformly into a horizontal mold from a feed chamber in a horizontal direction at a controlled rate, directly on top of the metal already within the mold. A cooling medium is applied to the bottom surface of the mold, with the type and flow rate of the cooling medium being varied to produce a controlled cooling rate throughout the casting process. The rate of introduction of molten metal and the flow rate of the cooling medium are both controlled to produce a relatively uniform solidification rate within the mold, thereby producing a uniform microstructure throughout the casting, and low stresses throughout the casting.

A method of casting a metal ingot having the steps of delivering molten metal to a direct chill mold, forming a solidified shell of metal, applying a coolant to a surface of the shell as it emerges from the mold, and withdrawing a solidified ingot from the mold. The coolant contains an oxidation inhibitor for increasing the rate of heat transfer from the solidifying metal compared to a coolant not containing the oxidation inhibitor to produce an ingot which is resistant to cracking.

Method of preventing cracking in direct chill cast ingots

A cooling mechanism for a casting apparatus having a mold that includes sides, a bottom, and a top defining a cavity. The cooling mechanism allows for simultaneous injection of liquid and gas onto a cast ingot therefore providing a lower minimum operation liquid flow rate, while maintaining a fairly constant coolant impingement location on the ingot surface. As a result, heat is extracted from the metal ingot at a much lower rate allowing the ingot to experience superior startup butt curl control, which substantially reduces the number of localized stresses that can lead to cracking of the ingot. Reducing the number of cracks in the ingot substantially reduces the number of wasted ingots, therefore improving efficiency and reducing costs. A method of casting is also disclosed.

Gas enhanced controlled cooling ingot mold

A DC casting mold for casting molten metal alloy comprising a cooled tubular body that has a thermally insulated insert attached to its top surface. The thermally insulated insert has a bottom portion with a beveled sidewall, which forms an angle with the horizontal melt surface layer of the molten metal and creates an eddy. The eddy causes a substantial number of oxides that are formed during the casting process to remain in the bottom sidewall portion of the thermally insulated insert of the mold, thereby substantially reducing the number of ingot surface imperfections that promote ingot cracking. In addition, the eddy promotes break-up of the oxides into smaller pieces as the oxides flow toward the cooled inner walls of the cooled tubular body, thereby having limited surface area for growth of oxide folds. A method of casting molten metal alloys with improved surface quality is also disclosed.

Controlled fluid flow mold and molten metal casting method for improved surface

An improved cylindrical bottom block for casting of large ingots or billets, particularly cylindrical shaped ingots, of light metals, such as aluminum and aluminum alloys, the cylindrical bottom comprising: (a) a base section having an outer diameter; (b) a centrally located circular surface forming the upper end of the base section, the circular surface positioned substantially perpendicular to the direction of casting, the circular surface forming the floor of the dish of the cylindrical bottom block which receives and cools liquid phase metal to form the butt end of an ingot, the circular surface being substantially flat and having a peripheral edge; (c) a cylindrical rim extending around the peripheral edge of the centrally located circular surface, the rim having an upper edge and an inner side wall which forms the side wall of the dish; (d) a concave transition section positioned between the peripheral edge and the lower end of the inner side wall, the concave transition section extending completely around the peripheral edge of the dish; (e) a convex transition section between the upper edge of the rim and the upper end of the inner side wall, the convex transition section extending completely around the dish; (f) the inner side wall having a flat central surface extending completely around the dish and defining the inner diameter of the dish; and (g) the upper edge of the rim having a flat surface positioned substantially parallel to the centrally located circular surface, the upper edge extending around the dish.

Non-hot crack bottom block for casting aluminum ingot

A method of quenching a metal object having steps of: (a) providing a liquid coolant having a temperature from about 100.degree. F. to about 180.degree. F. and containing about 0.01 to about 0.1 standard cubic feet of carbon dioxide gas per gallon of water dissolved therein; and (b) spraying the liquid coolant on the metal object to quench the metal object.

Spray quenching of metal with liquid coolant containing dissolved gas

A method of quenching a metal object comprising: (a) providing a reservoir of liquid coolant containing gas that has been dissolved therein; and (b) immersing the metal object in the reservoir to quench the metal. The gas is selected from the group consisting of nitrogen and carbon dioxide and is preferably carbon dioxide. The gas is preferably maintained within the range of 0.001 to 0.2 standard cubic feet of gas per gallon of coolant. The liquid coolant is preferably water. In a preferred embodiment, the reservoir of liquid coolant is open to ambient pressure and temperature.

Method of heat treating metal with liquid coolant containing dissolved

A method of gas fluxing molten aluminum with at least two, relatively small diameter upper and lower rotatable dispersers located in the molten aluminum and mounted on a shaft. Fluxing gas is added to the molten aluminum beneath each of the rotatable dispersers at a substantial rate of gas flow while rotating the dispersers at a substantial rpm in the molten aluminum. The dispersers directly shear gas bubbles that form in the molten aluminum as the fluxing gas is directed into the molten aluminum beneath each of the dispersers. The direct shearing of the gas bubbles maintains a high surface area between the bubbles and molten aluminum to effect efficient removal of impurities in the molten aluminum.

Method of gas fluxing with two rotatable dispensers

Process and apparatus for improving fluxing gas dispersion in treating molten aluminum by increasing the fluxing gas surface area. The process includes the use of a molten body of aluminum and a gas dispersing unit in the body of molten aluminum, the dispersing unit having at least two, upper and lower dispersers (rotors) mounted on a shaft extending into the molten aluminum. The dispersing unit is rotated, and simultaneously with the rotating, a fluxing gas is added to the molten aluminum adjacent the lower disperser. The fluxing gas is dispersed by the lower disperser to provide finely divided bubbles and then re-dispersed with the upper disperser to effectively increase the fluxing gas surface area in the molten body.

Purification of molten aluminum using upper and lower impellers

A mold for casting metal ingot sows having an aspect ratio of at least 4:1. The mold comprises a bottom wall from which a side wall extends upwardly and outwardly and from which heat transfer structure extends downwardly for transferring heat away from the bottom wall.

Mold for casting metal ingot sows and method

The present invention includes process and apparatus for continuously monitoring or detecting a liquid element or compound in another, different liquid including introducing a gas into a first liquid, measuring bubble size of bubble formation of the gas in the first liquid, introducing a second liquid element or compound into the first liquid to form a combination liquid, introducing a gas into the combination liquid, measuring bubble size of bubble formation of the gas in the combination liquid, and comparing gas bubble formation in the first liquid with gas bubble formation in the combination liquid to determine the amount of the second liquid in the combination liquid. The present invention further includes controlling or adjusting the amount of the second liquid contained in the first liquid in response to the monitoring and detecting determination of the present invention.

Liquid-in-liquid sensor and method

A method and apparatus for continuously monitoring the cooling capacity of a liquid coolant containing gas bubbles. The apparatus includes a measuring means for measuring the number density of the bubbles to infer the heat transfer characteristics of the liquid coolant, a control means for varying the amount of gas in the liquid coolant so that the number density is within a predetermined range and an electro-acoustic transducer in fluid contact with the liquid coolant capable of generating waves of sufficient intensity to cause cavitation in the liquid coolant in the area of the measuring means. In a preferred embodiment the electro-acoustic transducer is an ultrasonic horn.

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Murrysville, PA, United States of America

Ho Yu