EP1454680A1

EP1454680A1 - Aluminium lamination process

Info

Publication number: EP1454680A1
Application number: EP03380047A
Authority: EP
Inventors: Juan Luis Serratosa Caturla
Original assignee: Bancolor SL
Current assignee: Bancolor SL
Priority date: 2003-03-04
Filing date: 2003-03-04
Publication date: 2004-09-08

Abstract

Starting from a continuous casting furnace (1), fed with scraps, ingots or any other aluminum presentation, the cast metal is urged to pass through a solidification and rolling machine (5), a 19 mm-thick aluminum sheet being obtained. Then, this sheet is subjected to three successive hot rolling phases in respective rolling towers (8-8'-8"), attaining at its outlet a 1.5 mm thickness. Then, the aluminum sheet is subjected to two cold rolling phases until attaining a 0.54 mm thickness and, after intermediate annealing, it is subjected to a final cold rolling phase in which the definitive 0.25 mm thickness is obtained. The process achieves cutting the time of 34 hours corresponding to a classic continuous casting process down to 19 hours.

Description

OBJECT OF THE INVENTION

The present invention refers to a new aluminum rolling process in which, preferably starting from scraps of this material as raw material, an aluminum strip is obtained with thickness in the range of 0.25 mm.
The object of the invention is to obtain this result with a drastic reduction in process time, which could be placed in the range of 40%.

BACKGROUND OF THE INVENTION

For manufacturing rolled aluminum, in the form of coils, two systems are currently used.
The first system consists of hot-mill rolling, plus cold rolling and thermal treatments. More specifically, this system starts from rectangular aluminum blocks in the range of 50 cm high and 6 m long, the width of which is variable based on the width of the sheet intended to be obtained in the end, blocks commonly referred to as slabs, which on both their upper and lower face typically have slag and harmful elements for rolling, due to which an initial milling phase is carried out on both sides, after which the heating thereof ensues to a temperature comprised between 400 and 450°C. Then, they are introduced into a rolling mill which is provided with a roller table for transporting the strip in the longitudinal direction, and four rolling rollers, two working rollers and two support rollers, such that, upon clamping of the slab, the latter becomes thinner and longer.
After approximately 16 passes through said rolling mill, a strip with thickness in the range of 8 mm is obtained.
After said hot rolling, cold rolling follows in which the sheet undergoes three more passes through the corresponding rolling mill, attaining a 2 mm thickness for the aluminum sheet, but with a considerable increase in metal hardness, being thus necessary to carry out an annealing phase so that the cold rolling may proceed, the sheet undergoing two more passes until reaching the 0.6 mm thickness. At this time and because of the same hardness problem, it is necessary that the aluminum undergoes a new annealing and two new cold rolling passes in order to attain the definitive thickness intended to be obtained, 0.25 mm, with suitable mechanical properties.
The different operative phases of this process consume a time which can be placed in the range of 41 hours.
The second system which has been previously mentioned consists of a continuous casting process in which the liquid metal is obtained from melting scraps or ingots, urging said cast metal to pass between two rollers where, concurrently to its cooling and solidification, a continuous, 8 mm-thick sheet is produced.
In this case and in order to achieve the definitive 0.25 mm thickness, 5 passes through a cold rolling mill are carried out, subsequently the aluminum sheet is subjected to annealing, and it finally undergoes two new cold rolling passes.
With this second system, the time of 41 hours of the previous system is reduced to 34 hours.

DESCRIPTION OF THE INVENTION

The rolling process proposed by the invention constitutes a significant technological advance in this field as it achieves, as previously mentioned, a new and drastic reduction in the process time, which can be placed in the range of 19 hours.
In order to do so, said process also starts from an initial continuous casting phase for obtaining the cast metal which, immediately after exiting the furnace and, through the corresponding runner, is urged to pass through a twin-belt rolling machine where its solidification occurs, outputting a 19 mm-thick sheet at a speed of 8 or 9 m/min.
Afterwards, the obtained strip is urged to pass in tandem through three successive hot rolling towers, in each one of which the aluminum sheet thickness is gradually reduced, reaching a level of 1.5 mm and at a speed of 100 m/min.
Then, the aluminum sheet is subjected to two cold rolling passes by which its 1.5 mm thickness becomes 0.54 mm, afterwards a conventional annealing phase is carried out, and it is finally subjected to a new pass through a cold roller where the 0.54 mm-thick aluminum sheet attains the definitive 0.25 mm thickness.

DESCRIPTION OF THE DRAWINGS

To complement the description being made and for the purpose of helping to better understand the features of the invention according to a preferred practical embodiment thereof, a single sheet of drawings is attached to said description as an integral part thereof, which, with an illustrative and non-limiting character, shows a schematic side elevational view of a facility for putting into practice the aluminum rolling process constituting the object of the present invention.

PREFERRED EMBODIMENT OF THE INVENTION

In view of the indicated figure, it can be seen how, for putting the process of the invention into practice, it starts with a furnace (1), for example with a 90 ton capacity, which will be fed with aluminum scraps, ingots or any other presentation form of this raw material, said furnace (1) being assembled on a rocking shaft (2) which, with the cooperation of a hydraulic system (3), allows the rocking thereof for dumping the cast aluminum into a runner (4) which carries it in the liquid phase to the twin-belt rolling machine (5) where the material's solidification occurs and a 19 mm-thick aluminum sheet (6) is obtained, a machine (5) which works at a speed of 8/9 m/min, as previously mentioned.
A roller platform (7) is assembled at the machine (5) outlet connecting said machine to a first rolling tower (8), specifically hot rolling, with the classic support roller (9) and clamping roller (10) pair. Immediately after the rolling tower (8), there is another rolling tower (8') having identical features, and immediately after, a third tower (8"), such that at the outlet of the latter, the aluminum sheet has reached 1.5 mm thickness and advances at a speed of 100 m/min.
Beyond the three hot rolling towers (8-8'-8"), two winding machines (9-9') are assembled, alternatively collecting the material in respective coils (10-10') whose parity is determined by the continuous character of the process, since the coils (10-10') are normally in the range of 5,000 kg compared to said 90 t furnace (1) load, being thus necessary that, in order not to interrupt the process, when the coil (10) reaches its maximum capacity, the winding machine (9) stops operating, winding machine (9') starting while the full coil (10) is removed from the first one.
In the indicated figure, the elements corresponding to the end phases of the process have not been shown, in other words, the two cold rollers, the annealing furnace and also the cold end roller, as they constitute elements which structurally and functionally correspond to those with which a conventional continuous casting process also ends.

Claims

An aluminum rolling process in which aluminum scrap, aluminum ingots or any other presentation form thereof is used as the raw starting material, raw material which is melted in a furnace and which, by means of a continuous casting process, is fed into a stepped rolling facility, until attaining the definitive thickness in the range of 0.25 mm, characterized in that the following operative phases are established therein:

After exiting the casting furnace (1), the cast metal is passed through a solidification-rolling machine (5) in which a 19 mm-thick sheet is obtained.

Said 19 mm-thick sheet is subjected to three successive hot rolling phases in three rolling towers (8-8'-8") arranged in alignment, until reaching a thickness for the aluminum sheet in the range of 1.5 mm.

After the winding of said sheet, the sheet is subjected to two passes through a cold roller until attaining a 54 mm thickness.

Then, the aluminum sheet is subjected to an annealing phase.

Finally, the annealed aluminum is subjected to a cold rolling phase in which the definitive 25 mm thickness is obtained.