Process and plant for automatic casting of semi-finished products
AssigneesAluminum Pechiney, Pechiney Rhenald
InventorJacques Moriceau
Life of this patent
Estimating the term…
Abstract
In the process, which enables complete automation of casting and limiting the intervention of the operator, the level of metal in the supply runner is monitored, a common law of metal levels is set as a function of time for all ingot molds after individual laws have been applied to each of the molds in order to permit them to meet the common law, lowering of the table supporting the molds is actuated and the casting process is halted when the program length has been obtained. The apparatus comprises probes for detecting the height and levels of metal in the runner and in the ingot molds, and an automation system for adjusting the levels and controlling the various operations.
Claims9
A process for continuous casting of plates or billets of aluminum alloy from a casting furnace through a runner equipped with nozzles into a plurality of water-cooled ingot molds, each of said molds closed at a lower end by a bottom block and supported by a common table which moves vertically during casting, comprising the steps of:
- a) causing a stopper rod in each of said nozzles to be prepositioned at a point of closure for said nozzles;
- b) supplying liquid aluminum to the runner by tilting the casting furnace or by opening a casting hole in the casting furnace, the liquid aluminum filling the runner to a predetermined level;
- c) when the liquid aluminum fills the runner to said predetermined level, at a time T.sub.0, moving said stopper rods to a point corresponding to a predetermined initial aperture value, causing liquid aluminum to flow into the ingot molds;
- d) as a predetermined metal height above the bottom block dH is detected in each mold, automatically and individually adjusting the position of the stopper rod of the nozzle corresponding to said mold and thus adjusting the flow of aluminum so as to reach a predetermined metal common metal level N.sub.1 in all molds at a common time T.sub.1, variation of the aluminum level N in each mold being linear as a function of time between the level corresponding to dH and the level N.sub.1 ;
- e) at (T.sub.1,N.sub.1), imposing a common level function N=f(T) on all molds, until reaching a reference level N.sub.3 at time T.sub.3, then
- lowering the table at a predetermined speed, the level N being, after the time T.sub.3, a function of the length of cast product;
- and
- f) when the cast product reaches a predetermined length, stopping the supply of aluminum to the runner, casting the aluminum remaining in the runner and stopping the lowering of the table.
A process for continuous casting of plates or billets of aluminum alloy from a casting furnace through a runner equipped with nozzles into a plurality of water-cooled ingot molds, each of said molds closed at a lower end by a bottom block and supported by a common table which moves vertically during casting, comprising the steps of:
- a) causing a stopper rod in each of said nozzles to be prepositioned at a point defining a predetermined initial aperture for said nozzles;
- b) supplying liquid aluminum to the runner by tilting the casting furnace or by opening a casting hole in the casting furnace, the liquid aluminum filling the runner to a predetermined level;
- c) providing a dam located just upstream of the most upstream of said nozzles;
- d) when the liquid aluminum fills the runner to said predetermined level, at a time T.sub.0, removing said dam and causing liquid aluminum to flow into the ingot molds;
- e) as a predetermined metal height above the bottom block dH is detected in each mold, automatically and individually adjusting the position of the stopper rod of the nozzle corresponding to said mold and thus adjusting the flow of aluminum so as to reach a predetermined common level N.sub.1 in all molds at a common time T.sub.1, variation of the aluminum level N in each mold being linear as a function of time between the level corresponding to dH and the level N.sub.1 ;
- f) at (T.sub.1,N.sub.1), imposing a common level function N=f(T) on all molds, until reaching a reference level N.sub.3 at time T.sub.3, then
- lowering the table at a predetermined speed, the level N being, after the time T.sub.3, a function of the length of cast product;
- and
- g) when the cast product reaches a predetermined length, stopping the supply of aluminum to the runner, casting the metal remaining in the runner and stopping the lowering of the table.
In an apparatus for continuous casting of metal from a casting furnace through a runner equipped with nozzles into a plurality of water-cooled ingot molds, each of said molds closed at a lower end and supported by a common table which can be moved vertically, where a flow of metal is obtained either by tilting the casting furnace, or by opening a casting hole closed by a stopper rod, and is controlled in each nozzle by a stopper rod closing the nozzle, the improvement comprising:
- a) means for maintaining a constant level of metal in the runner, comprising means for detecting the metal level and means for controlling the tilting of the furnace or the position of the stopper rod closing the casting hole;
- b) means for activating the stopper rod of each nozzle, allowing partial or total closing of the nozzle;
- c) a metal level sensor installed above each ingot mold which generates a signal proportional to the increase in metal level in the mold;
- d) means for individually controlling the metal level in each ingot mold according to a predetermined level function, by moving the stopper rod of the nozzle corresponding to the ingot mold;
- e) means for detecting that a predetermined metal level has been reached in all ingot molds, and controlling descent of the table according to a predetermined speed function;
- and
- f) means for detecting that a predetermined length of cast product has been obtained and subsequently stopping descent of the table, closing the nozzles by actuating the stopper rod of each nozzle, and stopping the supply of metal from the casting furnace to the runner.
Dependencies are inferred from the claim text.