Process and apparatus for continuously casting metals
AssigneeVAW Aluminium AG
InventorsWolfgang Schneider, Horst-Dieter Lindlar, Roland Schmoll
Life of this patent
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Abstract
Process and apparatus for the continuous casting of aluminum alloys in multiple moulds to form continuous castings of improved quality. The invention comprises supplying gas at a predetermined gas flow rate to each mould during the mould filling stage, sensing the gas pressure during the second casting or cooling stage and increasing or reducing the gas flow rate to maintain a predetermined gas pressure in the moulds during the continuous extrusion process.
Claims37
A process for casting of continuous metal billets, ingots or bars in a multiple mould casting apparatus in which each mould comprises a hot top attachment, a movable casting base or table and a gas pipeline for introducing pressurized gas to said mould, comprising the steps of (a) supplying gas through each pipeline to each mould at a predetermined flow rate during a first casting-initiation step from the moment of introducing molten metal to each said mould until after the movable casting base is lowered and a portion of said metal casting is cooled;
- (b) sensing the gas pressure in said pipeline, and (c) automatically adjusting the gas flow rate to maintain the gas pressure at a predetermined nominal value during the formation of said continuous castings in a second casting step.
A process according to claim i in which the predetermined nominal value for the gas pressure in each gas pipeline corresponds to at least the metallostatic pressure of the melt when the mould is filled completely.
A multiple mould casting apparatus for the continuous casting of metals in a plurality of moulds each comprising a hot top attachment having a pressurized gas supply and a movable casting base which is lowerable to a cooling zone to cool continuous metal castings formed in the mould cavity between said hot top attachment and said casting base, said apparatus comprising a pipeline connected to each mould for supplying pressurized gas downstream thereto;
- means for regulating the flow rate of said pressurized gas to each of said moulds;
- means for sensing the gas pressure in each said pipeline at a location downstream of said regulating means and upstream of each said mould, and means for automatically adjusting said regulating means to maintain the gas pressure in said pipeline at a predetermined nominal value, whereby the gas flow rate is maintained constant at a predetermined value, independent of the gas pressure, during the first casting phase in which the mould cavities are being filled with molten metal and the casting base is lowered to initiate cooling of the casting and, subsequently thereto, the gas flow rate is regulated to a higher or lower value whenever the sensed gas pressure varies from a predetermined nominal pressure.
Dependencies are inferred from the claim text.