Comalco Aluminum Limited

Comalco Aluminium Limited

Alcoa of Australia Limited

Alcan Australia Limited

John A Eady

Rodney A Legge

Joseph R Ponteri

Rodney E Proposch

Christopher J Heathcock

Christopher Geoffrey Goodes

Kevin P Rogers

John C Nixon

Peter L Kean

A mould assembly comprising mould segments of generally non-thermally conductive material which define a mould cavity is upwardly filled with liquid metal through at least one in-gate. A thermal extraction member of a high thermally conductive material contacts a portion of the mould cavity through which heat is extracted rapidly to establish positive thermal gradients in the casting and thereby promote directional solidification. The mould assembly is also provided with a seal to selectively isolate the mould assembly from the liquid metal source to allow the mould assembly to be removed from the casting station and transferred to the cooling station, providing a more efficient use of the casting station. In addition, once a shell has solidified then the mould segments and metal contained therein can be transferred to the cooling station.

Casting of metal objects

The mould assembly comprises mould segments of generally non-thermally conductive material which define a mould cavity for receiving liquid metal through at least one in-gate. A thermal extraction member of a high thermally conductive material contacts a portion of the mould cavity through which heat can be extracted rapidly to establish positive thermal gradients in the casting and thereby promote directional solidification. The mould assembly is also provided with a seal to selectively isolate the mould assembly from the liquid metal source to allow the mould assembly to be removed from the casting station to the cooling station before any substantial solidification has occurred, providing a more efficient use of the casting station.

A cast hypereutectic Al-Si alloy with from 12-15% Si, having excellent wear resistance and machinability, improved fatigue strength and good levels of ambient and elevated temperature properties is provided, as well as a method of producing such alloy. The alloy and a melt used in the method contains Sr in excess of 0.10% and Ti in excess of 0.005%, the alloy further comprising: Cu 1.5 to 5.5%, Ni 1.0 to 3.00%, Mg 0.1 to 1.0%, Fe 0.1 to 1.0%, Mn 0.1 to 0.8%, Zr 0.01 to 0.1%, Zn 0 to 3.0%, Sn 0 to 0.2%, Pb 0 to 0.2%, Cr 0 to 0.1%, Na 0 to 0.01%, B (elemental) 0.05% maximum, Ca 0.003% maximum, P 0.003% maximum. Others 0.05 maximum each, the balance, apart from incidental impurities, being Al. The level of Sr in excess of 0.10% and Ti in excess of 0.005% is such that the alloy has a microstructure in which any primary Si formed is substantially uniformly dispersed and is substantially free of segregation, and in which substantially uniformly dispersed Sr intermetallic particles are present but are substantially free of such particles in the form of platelets, with the microstructure predominantly comprising a eutectic matrix.

Cast aluminium alloys and method

High purity coke particularly suited to the production of anodes for aluminium smelting is produced by an integrated process that includes flash pryolysis and delayed coking. In the integrated process, flash pyrolysis of carbonaceous materials such as coal, oil shale or tar sand is operated under conditions that maximize the production of tar suitable for coking, and the delayed coking is operated under conditions that maximize the coke yield, and intermediate products may be recycled to enhance overall efficiency.

Process for the production of high purity coke from coal

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Victoria, Australia

John A Eady