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(11) | EP 3 326 736 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | MACHINE FOR FORMING ALUMINIUM WEBS |
| (57) Described is a machine for making webs (1) made of aluminium, comprising: a unit
(2) for feeding aluminium in the liquid state along a feed line (A) having a feed
direction (V); an injector (3) of the aluminium in the liquid state, positioned downstream
of the feed unit (2) relative to the feed direction (V) having an inlet opening (4)
to receive the aluminium in the liquid state from the feed unit (2) and an outlet
opening (5) for feeding a calculated quantity of aluminium in the liquid state towards
a solidification zone; an upper roller (6) and a lower roller (7) with parallel axes
(X6, X7), rotating relative to each other according to opposite directions (V6, V7),
spaced from each other to form an opening or channel (8) having a first dimension
(L8) and defining the solidification zone; the upper roller (6) and the lower roller
(7) are configured for receiving aluminium in the liquid state from the outlet opening
(5) of the injector (3) and forming, at the outlet, a continuous, solid web (1) of
aluminium, having at least a thickness (S1) equivalent to the first dimension (L8)
and at least an upper surface (1a) and a lower surface (1b); one between the upper
roller (6) and the lower roller (7) has at least one recess (9, 10, 11) made on the
relative surface (6a, 7a) of contact with the aluminium, in such a way as to form
on the corresponding upper surface (1a) or lower surface (1b) of the web (1) being
formed a corresponding zone (12, 13, 14), at least repeated cyclically, having a thickness
(S12, S13, S14) greater than the thickness (S1) of the remaining web (1) being formed.
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[0001] This invention relates to a machine for making aluminium webs, by means of a continuous casting process.
[0002] More specifically, the machine according to this invention is used for the formation of aluminium webs by means of a process for the continuous casting of the molten aluminium, referred to by experts in the field as "twin roll casting".
[0003] The machines of this type basically comprise:
- a unit for feeding molten metal along a feed line having a direction;
- an injector of the molten metal, positioned downstream of the feed unit relative to the feed direction, having an inlet opening for receiving the molten metal from the feed unit, and an outlet opening for feeding a calculated quantity of molten metal towards a solidification zone;
- an upper roller and a lower roller (cylindrical) with parallel axes and configured for forming, by lamination, a continuous, solid, aluminium web; the two rollers are positioned downstream of the injector, with respect to the feed direction.
[0004] More specifically, the upper roller and the lower roller are rotating continuously in opposite directions, in such a way as to allow a feed of the continuous web in the same direction as the feed direction.
[0005] Moreover, the pair of rollers is mutually spaced, radially or relative to the corresponding relative axis, in such a way as to define an opening which will determine the thickness of the web being formed (distance calculated from the theoretical point of tangency of the two rollers). This distance is controlled by supporting and regulating (hydraulic) elements connected to each of the two rollers.
[0006] In addition, means (channels inside the rollers for the passage of a fluid) for cooling the outside surface of the rollers act on both the rollers to allow a correct passage of the metal from the liquid state to the solid state.
[0007] It should be noted that the injector is positioned with its outlet opening close to the opening defined by the two rollers and in a withdrawn position relative to the axis of the two rollers, which is also called the "set back" distance (or, also, "contact arc").
[0008] The outlet opening of the injector supplies the molten metal necessary for formation of the web towards the two rollers according to a predetermined width which is defined by containment elements or walls, located at the sides of the injector and which act as a barrier to the metal in the above-mentioned set back zone.
[0009] Consequently, the solidification step of the metal, that is to say, the passage of the metal from the liquid state at the outlet from the injector to the solid state at the outlet from the two rollers, occurs in the above-mentioned set back zone wherein the molten metal and the rollers come into contact.
[0010] During this passage the two rollers remove heat from the metal until it reaches firstly a semi-solid state and then a solid state to allow the formation of the web.
[0011] Between the outlet opening of the injector and the contact arc of the pair of rollers there is a solidification face, which is, therefore, upstream of the centre line of the rollers (referred to the feed direction) and generates the solidification of the metal at a thickness greater than that of the opening, that is, the distance (or gap), between the upper roller and the lower roller; distances which, in effect, determine the final thickness of the web.
[0012] In other words, the upper roller and the lower roller generate the shape of the product as elements for forming the web.
[0013] The strip being fed downstream of the rollers (normally along a horizontal plane) is then wound to form a roll.
[0014] The machine and the relative just described above allow the production of webs of variable thickness (in a range of usually between 2 and 12 mm) while the width of the web can be adjusted within a range which will be a function of the capacity of each machine.
[0015] Similarly, the size of the rollers varies according to the plant and is selected depending on of the subsequent transformation steps.
[0016] With this type of machine and the relative continuous casting process webs are produced of the, so to speak, symmetrical type, relative to the transversal profile of the web.
[0017] In other words, the two surfaces of greatest extension generated by the process have an extension which is flat and parallel to each other.
[0018] One of the many uses of these aluminium webs is, for example, in the "automotive" sector for making components by pressing of the semi-finished aluminium element.
[0019] The need is currently strongly felt in this sector of having webs ready formed with zones of different mechanical strengths for making sheet metal as the base for certain components in a fast and safe manner and with predetermined zones of different mechanical strength for the subsequent applications on the sheet metal.
[0020] However, this need is in conflict with current symmetrical shape of the webs and, therefore, this problem is solved by applying an addition of material (generating a shim on the web), for example by welding, in the predetermined zone(s) in order to have a reinforcement "patch".
[0021] This creates drawbacks due to:
- the addition of a processing step on the web with consequent additional times which, in fact, on large numbers of the same component can create a rise in costs;
- a possible reduction in the mechanical strength of the component in the joining points between the insert applied and the rest of the web precisely due to the joining of two separate components.
[0022] The aim of this invention is to provide a machine for making aluminium webs which overcomes the above-mentioned drawbacks of the prior art. More specifically, the aim of this invention is to provide a machine for making aluminium webs, in particular by the continuous casting process, which is able to form aluminium webs having surfaces with different mechanical strength characteristics in a fast, safe and precise manner.
[0023] A further aim of this invention is to provide a machine for making aluminium webs, in particular by the continuous casting process, which is able to form webs with zones with different mechanical strength with different geometrical configurations and is able to modify the zones, in a fast and safe manner, as a function of the production requirements. These aims are fully achieved by the machine for forming aluminium webs, in particular by using the continuous casting process, according to this invention as characterised in the appended claims.
[0024] More specifically, the machine for forming aluminium webs comprises a unit for feeding aluminium in the liquid state along a feed line having a feed direction.
[0025] The machine also comprises an injector of the aluminium in the liquid state, positioned downstream of the feed unit relative to the feed direction having an inlet opening to receive the aluminium in the liquid state from the feed unit and an outlet opening for feeding a calculated quantity of aluminium in the liquid state towards a solidification zone.
[0026] The machine comprises an upper roller and a lower roller with parallel axes, rotating relative to each other according to opposite directions, spaced from each other to form an opening or channel having a first dimension and defining the solidification zone.
[0027] The upper roller and the lower roller are configured for receiving aluminium in the liquid state from the outlet opening of the injector and forming, at the outlet, a continuous, solid web of aluminium, having at least a thickness equivalent to the first dimension of the opening and at least an upper surface and a lower surface.
[0028] The machine also comprises one between the upper roller and the lower roller with at least one recess made on the relative surface of contact with the aluminium, in such a way as to form on the corresponding upper surface or lower surface of the web being formed a corresponding zone, at least repeated cyclically, having a thickness greater than the thickness of the remaining web being formed.
[0029] Thanks to this type of the machine structure the aluminium webs formed may have zones with over-thicknesses located and defined by the geometry of the recesses.
[0030] The geometry of the web makes it possible to produce webs from continuous casting with zones clearly defined and with a greater mechanical strength relative to the remaining surface of the web, depending on intended requirements of the semi-finished product.
[0031] The structure of the machine makes it possible to make one or more recesses, with a closed perimeter, with a continuous or discontinuous annular shape, which provides zones with a different geometrical configuration on the web, guaranteeing a high production flexibility as a function of the production requirements.
[0032] This and other features will become more apparent from the following description of a preferred embodiment of the invention, illustrated by way of non-limiting example in the accompanying tables of drawings, in which:
- Figure 1 is a schematic side view, with some parts cut away to better illustrate others, of a machine for forming aluminium webs according to this invention;
- Figure 2 illustrates a schematic front perspective view of a part of a first embodiment of the machine for forming aluminium webs of Figure 1, and in particular two laminating rollers and a part of the web formed with the machine;
- Figures 3 and 4 illustrate, respectively, a side view and a top plan view of a part of the aluminium web formed in a second embodiment of the machine according to the preceding figures;
- Figure 5 illustrates a schematic front view of a pair of laminating rollers forming part of a third embodiment of the machine according to the preceding figures;
- Figure 6 illustrates a schematic front view of a pair of laminating rollers forming part of a fourth embodiment of the machine according to the preceding figures;
[0033] With reference to the accompanying drawings, and in particular to Figure 1, the machine according to the invention, denoted in its entirety with the numeral 100, is used for making webs 1 made of aluminium.
[0034] More specifically, the technical sector of the machine 100 is that of forming semi-finished products made of aluminium web, preferably continuous, through a continuous casting lamination process.
[0035] The machine 100 for making webs 1 made of aluminium (see Figure 1) comprises a unit 2 for feeding aluminium in the liquid state along a feed line A having a feed direction V.
[0036] The machine 100 also comprises an injector 3 of the aluminium in the liquid state, positioned downstream of the feed unit 2 relative to the feed direction V having an inlet opening 4 to receive the aluminium in the liquid state from the feed unit 2 and an outlet opening 5 for feeding a calculated quantity of aluminium in the liquid state towards a solidification zone.
[0037] The machine 100 also comprises an upper roller 6 and a lower roller 7 (preferably cylindrical) with parallel axes X6 and X7.
[0038] The upper roller 6 and a lower roller 7 rotate relative to each other according to opposite directions V6, V7 and spaced from each other to form an opening or channel 8 having a first dimension L8 and defining the solidification zone.
[0039] The term "first dimension" is used to mean a value (which can be modified) calculated between the two rollers in the hypothetical tangential point and relative to the corresponding relative axis.
[0040] The upper roller 6 and the lower roller 7 are configured for receiving aluminium in the liquid state from the outlet opening 5 of the injector 3 and forming, at the outlet, a continuous, solid web 1 of aluminium, having at least a thickness S1 equivalent to the first width L8 and at least an upper surface 1a and a lower surface 1b (the solid web 1 moves along the feed direction V thanks to the opposite directions V6 and V7 of rotation of the two rollers 6 and 7).
[0041] As illustrated (see also Figures 2, 5 and 6) at least one between the upper roller 6 and the lower roller (7) has at least one recess 9, 10, 11 made on the relative surface 6a, 7a of contact with the aluminium, in such a way as to form on the corresponding upper surface 1a or lower surface 1b of the web 1 being formed a corresponding zone 12, 13, 14, at least repeated cyclically, having a thickness S12, S13, S14 greater than the thickness S1 of the remaining web 1 being formed.
[0042] In other words, one of the two rollers is mechanically machined to have a different contact surface with the aluminium being solidified to obtain, during the continuous casting process, a greater thickness along the web in such a way as to modify the mechanical strength of the web.
[0043] The web will, therefore, have "asymmetrical" zones in its transversal and/or longitudinal cross-section as a function of the recess created.
[0044] As described in more detail below, the geometrical configuration of the recess and the number of recesses (and the depths) can have multiple combinations as a function of the needs for the use of the aluminium webs, without thereby limiting the scope of protection of this invention.
[0045] It should be noted that the definition of a zone with a thickness greater than the thickness of the web is used to mean that the zone has a thickness which comprises the sum of the thickness of the web and the additional thickness due to the recess and which is quantified (as described in more detail below) by the depth of the recess in the roller. Preferably, but not necessarily, the at least one recess 9, 10, 11 is formed on the upper roller 6.
[0046] Consequently, reference is made hereafter, by way of non-limiting example, to the upper roller 6 for descriptive simplicity, but this does not mean that the same technical features cannot be applied to the lower roller 7 without thereby limiting the scope of protection.
[0048] In a first solution (Figures 1 and 2), preferably the at least one recess comprises at least one impression 9 with a closed perimeter made on an curved portion of the contact surface 6a of the upper roller 6.
[0049] The impression 9 is configured to form on the corresponding upper surface 1a of the web 1 being formed a corresponding area 12 with a closed perimeter, repeated cyclically, having a thickness S12 greater than the thickness S1 of the remaining web 1.
[0050] In the case illustrated in Figures 1 and 2, for example, the impression 9 has a circular shape in such a way as to form a closed cylindrical zone with a thickness S12 along the surface 1a of the web 1 being formed, repeated cyclically, at a distance or spacing equal to a circumference of the upper roller 6.
[0051] In a second example (Figures 3 and 4), the impression 9 has a elliptical shape in such a way as to form a closed elliptical zone with a thickness S12 along the surface 1a of the web 1 being formed, repeated cyclically, at a distance or spacing equal to the circumference of the upper roller 6. According to a second embodiment, the at least one recess comprises at least one partial annular groove 10 formed along the upper surface 6a of contact of the upper roller 6 and configured to form on the corresponding upper surface 1a of the web 1 being formed a corresponding continues band-like zone 13 having a thickness S13 greater than the thickness S1 of the remaining web 1.
[0052] It should be noted that the partial annular groove 10 has an interruption along the upper surface 6a of contact of the roller 6 designed to form a corresponding partial interruption between a previous continues band-like zone 13 and a subsequent continues band-like zone 13' on the continuous web 1 (see Figures 3 and 4), in such a way as to form a spacing P equal to a circumference of the upper roller 6.
[0053] The spacing P can vary as a function of the dimension, that is to say, the circumference of the roller or of the rollers 6 and 7.
[0054] A third constructional solution is illustrated in Figure 5, wherein the at least one recess comprises at least one continuous groove 11 (annular) formed along the contact surface of the upper roller 6.
[0055] The continuous groove 11 is configured to form on the corresponding upper surface 1a of the web 1 being formed a corresponding continues band-like zone 14 (shown partially dotted in Figure 4) having a thickness S14 greater than the thickness S1 of the remaining web 1.
[0056] Starting from these individual examples, the solution allows a series of structural combinations such as to define several zones with greater thickness on the web being formed.
[0057] As illustrated in Figures 2 and 5, on at least one between the upper roller 6 and the lower roller 7 there are at least two recesses 9, 10 or 11 spaced from each other at least along the axial extension of the at least one roller 6 or 7).
[0058] Preferably, the at least two recesses 9, 10, 11 are made on the at least one roller 6 or 7 with the same depth P9, P10, P11 calculated starting from the surface of contact 6a or 7a of the at least one roller 6 or 7 in such a way as to generate corresponding zones 12, 13, 14 on the web 1 being formed having same thicknesses S12, S13, S14, greater than the thickness S1 of the remaining web 1.
[0059] According to an alternative embodiment, the at least two recesses 9, 10 or 11 are made on the at least one roller 6 or 7 with corresponding different depths P9, P10, P11 calculated starting from the surface of contact 6a or 7a of the at least one roller 6 or 7 in such a way as to generate corresponding zones 12, 13, 14 on the web 1 being formed having different thicknesses S12, S13, S14, again greater than the thickness S1 of the remaining web 1.
[0060] A fourth constructional embodiment the recess is illustrated in Figure 6, wherein the at least one recess comprises a groove 15 with a helical extension formed along the surface of contact 6a or 7a of the at least one roller 6 or 7 and extending about the axis X6 or X7 of the roller 6 or 7 in such a way as to form on the corresponding upper surface 1a or lower surface 1b of the web being formed a corresponding zone (continuous) having a thickness greater than the thickness S1 of the remaining web 1 being formed.
[0061] It should be noted that the upper roller 6 and the lower roller 7 are connected to corresponding hydraulic supporting means (not illustrated) which are capable of modifying the relative distance between the two rollers in such a way as to modify the size of the channel 8.
[0062] Moreover, on the rollers 6 and 7 there are corresponding cooling units (inner) for cooling the contact surfaces 6a and 7a (not illustrated).
[0063] The machine may also comprise a surface (usually horizontal and not fully illustrated) for supporting the webs formed as they move forward. Alternatively, the web being formed may be suspended and moved by a pulling force exerted by a winding reel on which the web is progressively wound.
[0064] Moreover, the above-mentioned solidification zone is defined by containment walls (not illustrated), located to the sides of the outlet opening of the injector and which act as a lateral barrier to the aluminium in the liquid state being fed.
[0065] Preferably, the feed unit 2 comprises a tank 16 for containing aluminium in the liquid state.
[0066] Downstream of the tank 16 there is a supply channel 17 configured to supply the aluminium in the liquid state to the injector 3.
[0067] A unit 18 for regulating the flow rate of the aluminium in the liquid state is positioned between the containment tank 16 and the supply channel 17. The feed unit 2 comprises a sensor 19 for measuring the level of the aluminium in the liquid state in the supply channel 17.
[0068] The feed unit 2 also comprises a control unit 20 connected to the measurement sensor 19 and the unit 18 for regulating the flow rate.
[0069] The control unit 20 is configured for controlling, with corresponding signals S20, the regulating unit 18 between several operating configurations between a minimum opening or a maximum opening (modular regulation) as a function of a given level measurement value, sent by the measurement sensor 19, different from or equal to a reference value set in the control unit 20.
[0070] It should be noted that the control unit 20 can be programmed to send, irrespective of the measurement data of the control sensor 19, at least one signal configured to activate the regulating unit 18 towards its maximum opening at the passage of the at least one recess 9, 10, 11 or 15 of the at least one roller 6 or 7 in the solidification zone.
[0071] Thanks to this programming of the unit it may be possible (in the case of a large number of deep recesses) to foresee any fast lowering of the level of liquid aluminium and the consequent absence of product in the injector so as to prevent incorrect formations along the web being formed.
1. A machine for making webs (1) made of aluminium, comprising at least:
- a unit (2) for feeding aluminium in the liquid state along a feed line (A) having a feed direction (V);
- an injector (3) of the aluminium in the liquid state, positioned downstream of the feed unit (2) relative to the feed direction (V) having an inlet opening (4) to receive the aluminium in the liquid state from the feed unit (2) and an outlet opening (5) for feeding a calculated quantity of aluminium in the liquid state towards a solidification zone;
- an upper roller (6) and a lower roller (7) with parallel axes (X6, X7), rotating relative to each other according to opposite directions (V6, V7), spaced from each other to form an opening or channel (8) having a first dimension (L8) and defining the solidification zone; the upper roller (6) and the lower roller (7) being configured for receiving aluminium in the liquid state from the outlet opening (5) of the injector (3) and forming, at the outlet, a continuous, solid web (1) of aluminium, having at least a thickness (S1) equivalent to the first width (L8) and at least an upper surface (1a) and a lower surface (1b),
characterised in that at least one between the upper roller (6) and the lower roller (7) has at least one recess (9, 10, 11, 15) made on the relative surface (6a, 7a) of contact with the aluminium, in such a way as to form on the corresponding upper surface (1a) or lower surface (1b) of the web (1) being formed a corresponding zone (12, 13, 14), at least repeated cyclically, having a thickness (S12, S13, S14) greater than the thickness (S1) of the remaining web (1) being formed.2. The machine according to claim 1, wherein the at least one recess comprises at least
one impression (9) with a closed perimeter made on an curved portion of the contact
surface (6a or 7a) of the at least one roller (6 or 7); the impression (9) being configured
to form on the corresponding upper surface (1a) or lower surface (1b) of the web (1)
being formed a corresponding area (12) with a closed perimeter, repeated cyclically,
having a thickness (S12) greater than the thickness (S1) of the remaining web (1).
3. The machine according to claim 1, wherein the at least one recess comprises at least
one partial annular groove (10) formed along the surface (6a or 7a) of contact of
the at least one roller (6 or 7) and configured to form on the corresponding upper
surface (1a) or lower surface (1b) of the web (1) being formed a corresponding continues
band-like zone (13) having a thickness (S13) greater than the thickness (S1) of the
remaining web (1); the partial annular groove (10) having an interruption along the
surface (6a or 7a) of contact of the at least one roller (6 or 7) designed to form
a corresponding partial interruption between a previous continues band-like zone (13)
and a subsequent continues band-like zone (13') on the continuous web (1), in such
a way as to form a spacing (P) equal to a circumference of the at least one roller
(6 or 7).
4. The machine according to claim 1, wherein the at least one recess comprises at least
one continuous groove (11) formed along the surface of contact of the at least one
roller (6 or 7) and configured to form on the corresponding upper surface (1a) or
lower surface (1b) of the web (1) being formed a corresponding continues band-like
zone (14) having a thickness (S14) greater than the thickness (S1) of the remaining
web (1).
5. The machine according to any one of the preceding claims, wherein on at least one
between the upper roller (6) and the lower roller (7) there are at least two recesses
(9, 10 or 11) spaced from each other at least along the axial extension of the at
least one roller (6 or 7).
6. The machine according to claim 5, wherein the at least two recesses (9, 10, 11) are
made on the at least one roller (6 or 7) with the same depth (P9, P10, P11) calculated
starting from the surface of contact (6a or 7a) of the at least one roller (6 or 7)
in such a way as to generate corresponding zones (12, 13, 14) on the web (1) being
formed having same thicknesses (S12, S13, S14), greater than the thickness (S1) of
the remaining web (1).
7. The machine according to claim 5, wherein the at least two recesses (9, 10, 11, 15)
are made on the at least one roller (6 or 7) with corresponding different depths (P9,
P10, P11) calculated starting from the surface of contact (6a or 7a) of the at least
one roller (6 or 7) in such a way as to generate corresponding zones (12, 13, 14)
on the web (1) being formed having different thicknesses (S12, S13, S14), again greater
than the thickness (S1) of the remaining web (1).
8. The machine according to any one of the preceding claims, wherein the at least one
recess (9, 10, 11) is made on the upper roller (6).
9. The machine according to any one of the preceding claims, wherein the at least one
recess (9, 10, 11) comprises a groove (15) with a helical extension formed along the
surface of contact (6a or 7a) of the at least one roller (6 or 7) and extending about
the axis (X6 or X7) of the roller (6 or 7) in such a way as to form on the corresponding
upper surface (1a) or lower surface (1b) of the web (1) being formed a corresponding
zone having a thickness greater than the thickness (S1) of the remaining web (1) being
formed.
10. The machine according to any one of the preceding claims, wherein the feed unit (2)
comprises:
- a tank (16) for containing aluminium in the liquid state,
- a supply channel (17) configured for feeding aluminium in the liquid state to the injector (3);
- a unit (18) for regulating the flow rate of the aluminium in the liquid state positioned between the containment tank (16) and the supply channel (17);
- a sensor (19) for measuring the level of the aluminium in the liquid state in the supply channel (17);
- a control unit (20) connected to the measurement sensor (19) and the unit (18) for regulating the flow rate; the control unit (20) being configured for controlling, with corresponding signals (S20), the regulating unit (18) between several operating configurations included between a minimum opening or a maximum opening as a function of a given level measurement value, sent by the measurement sensor (19), different from or equal to a reference value set in the control unit (20).
11. The machine according to claim 10, wherein the control unit (20) is programmed to
send, irrespective of the measurement data of the control sensor (19), at least one
signal configured to bring towards a maximum opening the regulating unit (18) at the
passage of the at least one recess (9, 10, 11) of the at least one roller (6 or 7)
in the solidification zone.