Systems for heating billets made of non-ferrous materials

Abstract

A system for heating metal billets (10) made of non-ferrous material and of various lengths and diameters, comprising a fixed base (2) supporting at least one heating means or furnace (3) configured to receive the metal billet during heating, and movable gripping means (15, 16) having gripping arms (22, 28) configured to hold the metal billet during heating in the furnace, each of the gripping arms (22, 28) coupled to a corresponding support and drive structure (21, 27), the movable gripping means (15, 16) being located at two opposite ends (3A, 3B) of the furnace (3), at least one of the movable gripping means (15, 16), a first movable gripping means, being movable along the fixed base relative to the other of the movable gripping means (15, 16). Both of the movable gripping means (15, 16) are movable relative to each other, the first movable gripping means (15) comprising a support which is movable on the fixed base (2) and which supports the second movable gripping means (16) which is movable on the support (17).

Description

[Technical Field]

[0001] The object of the present invention is to provide a system as set out in the preamble of the main claim, which is adapted to heat at least one metal billet made of a non-ferrous material and having various lengths and diameters. [Background technology]

[0002] Systems of the type described above have been known for a long time. They comprise one or more heating means or furnaces arranged to heat billets which are taken from a special support or store and taken into and held in the heating means or furnace. The heating means or furnaces may be of various types, for example gas or electromagnetic or magnetic induction furnaces, or other known heating means.

[0003] Specifically, but not exclusively, placing a ferromagnetic, paramagnetic, diamagnetic, or conductive metal body in a magnetic field generates an induced current within the metal body, causing the metal body to heat due to the Joule effect. Utilizing this physical principle, a metal billet (made of a non-ferrous metal) can be heated to make it more pliable, thereby facilitating deformation in, for example, a post-processing extrusion process or a post-processing heat treatment process.

[0004] Furnaces of the above mentioned type include, for example, magnetic induction types (such as those described in US Patent Publication No. 2010 / 147833) or permanent magnet types supported by a ring rotating on the same axis within an electric motor (such as those described in WO 2017 / 081532), which generate a rotating magnetic field that, by Joule effect, heats the billet contained in the furnace cavity.

[0005] The system of the present invention is preferably a magnetic induction furnace, particularly one of the type having a fixed or cylindrical, tubular body, including an electric stator integrally connected to the fixed body and an annular rotor, the latter being driven in rotation within the fixed body and within the electric stator about its longitudinal axis. The annular rotor is integrally connected to a rotor or tubular support having a longitudinal axis coaxial with the axis of rotation of the annular rotor and including a plurality of permanent magnets arranged to rotate the annular rotor and rotor to define a furnace cavity containing at least one billet to be heated by magnetic induction. During heating, the billet is held by a plurality of gripping means that prevent the rotor and tubular support from rotating about their longitudinal axes. This is because, without these gripping means, the billet would rotate, or attempt to rotate, about its longitudinal axis in the rotating magnetic field generated by the permanent magnets supported by the rotor. Furthermore, the billet may not be properly aligned within the furnace. Such rotation or improper alignment can adversely affect the positioning of the billet within the furnace and the heat treatment of the billet. Rotation and improper alignment can adversely affect successful heating of the billet.

[0006] Known systems configured to heat metal billets are typically quite large, especially when gas is used to heat the metal billet. Furthermore, gas-fed systems require the system to operate continuously in successive cycles, which inevitably results in high maintenance costs.

[0007] Moreover, known systems have a large number of components and are therefore expensive to maintain.

[0008] In summary, in the known systems described above, the billet stretches, deforms and expands during heating, which, like the rotation described above, can lead to inadequate support of the billet within the furnace, potentially damaging the support members or the internal components of the furnace, as well as displacing the point of good heating position (position along the furnace axis). Summary of the Invention [Problem to be solved by the invention]

[0009] SUMMARY OF THE INVENTION It is an object of the present invention to provide a system for heating metal billets made of non-ferrous materials that is improved over similar known systems. In particular, the object of the present invention is to provide a system for heating metal billets that properly takes into account and compensates for the deformations and elongations of the billets that occur during the heat treatment of the billets, so as not to negatively affect the desired heating of each billet and to prevent damage to the associated machine elements during the process in which the billets encounter the system or its special machine elements that perform said heating.

[0010] Another object of the present invention is to provide a system for heating metal billets which is reduced in size and maintenance costs over known similar systems.

[0011] Another object of the present invention is to provide a system which can heat non-ferrous metal billets in a good and uniform manner, i.e., with very good thermalization, and which can provide a uniform temperature to the billet both along the diameter and longitudinal axis of the billet.

[0012] Another object of the present invention is to provide a system of the type described which allows for rapid and well-controlled heating cycles of the billet.

[0013] Another object of the present invention is to provide a system that allows the components of the system that heat the billet (furnace) to be cooled quickly after heat treating the billet.

[0014] Another object of the present invention is to provide a system capable of automatically controlling the heating of a metal billet, which continuously controls the internal temperature of the metal billet during the heating process and the surface heating of the billet each time heating is completed, thereby enabling transition to heating of the next billet to be heated according to the temperature measured on the outer surface of the heated billet. [Means for solving the problem]

[0015] These objectives, and others which will be apparent to those skilled in the art, are achieved by the system set forth in the claims.

[0016] For a better understanding of the invention, the following drawings are attached, given purely as non-limiting examples: [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a perspective view from one side of a system according to the invention in a first operational stage; FIG. [Figure 2] FIG. 2 is a side view of the system shown in FIG. 1. [Figure 3] FIG. 2 is a perspective view of the system shown in FIG. 1 in a second operational stage. [Figure 4] FIG. 4 is a side view of the system shown in FIG. 3. [Figure 5] FIG. 2 is a perspective view of the system shown in FIG. 1 in a third operational stage. [Figure 6] FIG. 2 is a plan view of the system shown in FIG. [Figure 7] FIG. 2 is a perspective view of components of the system shown in FIG. 1. [Figure 8] FIG. 8 is a front view of the components shown in FIG. 7. [Figure 9] FIG. 8 is a side view of the components shown in FIG. 7. [Figure 10] FIG. 2 is an enlarged view of a portion indicated by the symbol A in FIG. [Figure 11] FIG. 3 is a front view of the area indicated by the symbol B in FIG. 2. [Figure 12] FIG. 2 is a perspective view of the system shown in FIG. 1 with some components omitted in a fourth operational stage. [Figure 13] 11 is a view similar to that shown in FIG. 10, but omitting some components of a system according to the present invention and emphasizing other components. [Figure 14] FIG. 14 is a front view of the components shown in FIG. 13. [Figure 15]FIG. 2 is a perspective view of the system shown in FIG. 1 showing additional components. [Figure 16] FIG. 16 is a perspective view of an additional component shown in FIG. 15. [Figure 17] FIG. 16 is a side view of the additional components shown in FIG. 15. DETAILED DESCRIPTION OF THE INVENTION

[0018] With reference to the accompanying drawings, particularly Figures 1 to 6, 14 and 17, one example of a system according to the present invention is generally designated by the reference numeral 1. The system according to the present invention comprises a fixed base 2, which in the illustrated embodiment supports three heating means, for example magnetic induction furnaces 3 arranged adjacent to one another in succession. These magnetic induction furnaces are resiliently connected to one another (to reduce vibration) by elongated flat plates 4 that restrain the magnetic induction furnaces 3. The magnetic induction furnaces are further resiliently mounted on side supports 5 that rise from the fixed base 2 and are mechanically integrally connected to the side supports in a known manner. The side supports 5 also comprise a chamber 6 that houses a power supply for the heating means, i.e., the magnetic induction furnaces 3.

[0019] It is clear that the system 2 according to the present invention may comprise only one or more heating means, i.e. furnaces 3, or may comprise other forms of heating means (e.g. gas furnaces), and may also comprise more than two furnaces (or heating means).

[0020] The heating means or furnace 3 is arranged with a common longitudinal axis W (see FIG. 6) parallel or horizontal to the plate or support P on which the system 1 (FIG. 1) according to the present invention rests and to which the fixed base 2 is fixed.

[0021] According to a preferred but non-limiting embodiment shown in the accompanying drawings, each heating means or furnace 3 is configured to heat an object 10 (for example, an aluminum alloy billet) having a cylindrical body 11 (solid, hollow, or tubular, with no particular cross-sectional shape) by magnetic induction. As will be described below, the object or billet 10 (hereinafter simply referred to as the "billet") is positioned within a furnace cavity 12, which includes means configured to generate, by magnetic induction, radial and axial magnetic fields of varying strength around and within the billet, thereby generating induced currents within the billet that heat the billet to a desired temperature, for example, about 500°C (for aluminum alloys) or higher (for other non-ferrous materials, such as alloys known as copper, bronze, brass, silver, magnesium, titanium, or cupronickel).

[0022] The billet may be constructed as a single piece, or may be constructed from multiple billet components joined together longitudinally to form a cylindrical body 11 of the desired length.

[0023] A furnace of this kind is described, for example, in WO 2017-081532.

[0024] The cavity 12 of each furnace 3 is configured to accommodate the billet 10 so that the billet does not undergo rotational movement about its longitudinal axis (which coincides with the longitudinal axis W) during heating when a magnetic field is generated within the cavity 12 to heat the billet by magnetic induction. Thus, to prevent rotation of the billet about its longitudinal axis, the billet is supported by the above-described configuration of the system 1 according to the present invention and held completely fixed and stationary within the cavity 12 during heating of the billet.

[0025] The system 1 according to the invention comprises two parts, first and second gripping parts 15 and 16, each adapted to cooperate with a respective billet 10 to place the billet in the furnace or heating means 3 and to hold the billet as it is exposed to the heat generated by the furnace. These parts of the system according to the invention, hereinafter referred to as "gripping means 15 and 16", are both movable relative to each other and to the fixed base 2. In particular, gripping means 16 is movable relative to gripping means 15, as will be explained below.

[0026] These gripping means provide good support for the billet 10 during each stage of the heat treatment, including displacement, loading into furnace 3, support during heating, and removal from the furnace. Furthermore, as will become apparent from the following description, these gripping means also compensate for the normal radial and longitudinal expansion of the billet when subjected to heating.

[0027] These parts of the system according to the invention, namely the first and second gripping means 15 and 16, are made up of several components.

[0028] More specifically, the first gripping means 15 is disposed opposite a first end 3A of the furnace (or "furnace group") 3, while the second gripping means 16 is disposed opposite a second end 3B of the furnace 3. The first gripping means 15 comprises a beam 17 disposed along the fixed base 2 at a lower position than the furnace 3, the beam being movable along the fixed base 2 on a pair of linear guides 18 (or "first guides") integrally connected to the fixed base 2. Movement of the beam is effected by an electric motor 20 integrally connected to the fixed base. The electric motor drives a pinion which cooperates with a rack 26 integrally connected to the beam 17 (see, e.g., Figures 1, 2 and 5).

[0029] The beam 17 (i.e., carrying or elongated structure) supports at a first end 17A of the beam (fixed thereto) a support and drive structure 21 which supports and drives a first gripping arm 22 configured to cooperate directly with the first end 11A of the billet cylinder 11 to be heated. A second end 17B of the beam 17 supports a second gripping means 16 which is movable relative to and on the beam as will be described below.

[0030] The first gripping means 15 (i.e. the part 15 that forms part of the system according to the present invention) therefore comprises a beam 17 movable on a pair of linear guides 18 integrally connected to the fixed base 2, a support drive structure 21 and a first gripping arm 22 configured to cooperate with the billet.

[0031] The first gripping means 15 as a whole (including the beam 17, the support and drive structure 21 and the first gripping arm 22) is moved on the fixed base 2 by means of an electric motor 20 cooperating with a rack 26 fixed to the beam 17.

[0032] The second end 17B of the beam 17 of the first gripping means 15 supports a face member 25 provided with a second pair of guides 18A (see FIG. 5 ), along which the second gripping portion 16 of the system moves. The second gripping portion, like the first gripping portion, will hereinafter be referred to as the “second gripping means 16.” The second gripping means comprises several components, and in particular, the second gripping means includes a support and drive structure 27 that supports and drives a second gripping arm 28 configured to directly cooperate with the second end 11B of the cylindrical body 11 of the billet to be heated. The support and drive structures 21 and 27 will hereinafter be referred to as the first and second support and drive structures, respectively. The first and second gripping arms 22 and 28 are aligned (coaxial), and both gripping arms are aligned with the cavity 12 of the furnace 3. Thus, the first and second gripping arms 22 and 28 are disposed along an axis W (see FIG. 6).

[0033] The second support and drive structure 27 supports an electric motor 30 which drives a recirculating ball screw 31 , the rotation of which controls the movement of the entire second support and drive structure 27 on the surface member 25 .

[0034] Therefore, the second gripping means 16 is provided on a plane member 25 supported by a beam 17 so as to be movable from the first gripping means along a second pair of guides 18A.

[0035] Such second gripping means 16 includes an electric motor 30 acting on a ball screw 31, a second support drive structure 27, and a second gripping arm 28, and the electric motor, second support drive structure, and second gripping arm move the second gripping means 16 (particularly, the second support drive structure 27 of the second gripping means 16) on the above-mentioned surface member 25.

[0036] Therefore, the second gripping means 16 moves on the surface member 25 (specifically, by the electric motor 30 and the ball screw 31) independently of the first gripping means. In other words, the second gripping means 16 moves independently of the first gripping means 15. Therefore, all components (27, 28, and 30) of the second gripping means 16 move independently of the components 17, 21, and 22 that make up the first gripping means 15.

[0037] Thus, in particular, the first and second gripping arms 22 and 28 are independent of each other.

[0038] More specifically, by movement of the second support drive structure 27 of the second gripping means 16 on the face member 25 of the first gripping means 15, one end 28A of the second gripping arm 28 is taken into each furnace 3 until it protrudes from the first end 3A of the furnace or furnaces 3 (see Figures 1, 10 and 12), and the one end 28A, which is not in contact until it comes into contact with the second end 11B of the billet 10 to be heated, is positioned on a support 32 provided facing the first end 3A of the furnace 3. Thus, the billet is pressed by the second support arm 28 toward the first gripping arm 22.

[0039] It should be noted that the second gripping arm 28 is integrally coupled to the second support and drive structure 27 so as to be cantilevered therefrom (see FIG. 5), and that the second gripping arm has a length sufficient to move with its uncontacted end 28A outside the first end 3A of the furnace 3 (see, for example, FIGS. 1 and 10) when the second support and drive structure 27 is positioned at the second end 3B of the furnace (the second gripping arm 28 extends into the cavity 12, see FIG. 1). In this way, the billet is pressed into contact with the first gripping arm 22, and the billet is clamped between the first and second gripping arms 22 and 28.

[0040] Therefore, when the electric motor 30 is driven, the circulating ball screw is driven, and the second support drive structure 27 of the second gripping means 16 moves along the second pair of guides 18A (on the surface member 25 of the first gripping means 15), and the second gripping member 28 penetrates into the furnace until the uncontacted end 28A is outside one end 3A of the furnace.

[0041] In this way, the previously uncontacted end of the second gripping arm comes into contact with the billet 10 and presses the billet toward the first gripping arm 22 protruding from the first support and drive structure 21 of the first gripping means 15. As a result, the billet is clamped between the first and second gripping arms 22 and 28.

[0042] The above-described movement of the second supporting and driving structure 27 and corresponding movement of the second gripping arm 28 grips and secures the billet 10 within the furnace 3. After the billet 10 is clamped between the first and second gripping arms 21 and 28, the electric motor 20 can be driven to move the beam 17 of the first gripping means 15 (and hence the movement of the first supporting and driving structure 21 and associated first gripping arm 22) along the fixed base 2 (FIG. 5), while also causing movement of the second gripping arm 28 of the second gripping means 16, which is supported on the beam 17 of the first gripping means 15 (which remains fixed to the beam).

[0043] When the billet 10 is positioned along the longitudinal axis W (along which the first and second gripping arms 22 and 28 and the cavity 10 of the furnace 3 lie, which is also the longitudinal axis of the billet, cavity, and gripping arms), movement of the beam 17 on the fixed base 2 causes movement of the billet 10 (which is "clamped" between the first and second gripping arms 22 and 28) within the cavity of the furnace 3, as shown in FIG. 5.

[0044] Therefore, the translation of the billet is carried out reliably and efficiently.

[0045] As a result, the billet 10 is held by the first and second gripping arms 22 and 28 so that the billet does not rotate about its longitudinal axis even when the furnace 3 is operating while being exposed to rotation caused by the rotating magnetic field acting on the furnace 3.

[0046] The first gripping arm 21 cooperates with a load cell 23 (shown diagrammatically in FIGS. 1-4 and 12) mounted on the first support and drive structure 21 of the first gripping means 15, which detects the clamping force on the billet between the first and second gripping arms 22 and 28. A control unit (not shown) of the system 1 according to the present invention controls all of the electric motors driving the first and second gripping means 15 and 16 and is connected to the load cells to ensure the clamping force on the billet, and controls the drive of the electric motor 30 to regulate the independent movement of the second gripping arm 28 relative to the first gripping arm 22, thereby compensating for axial expansion or deformation (along the longitudinal axis W) of the billet 10 upon exposure to heat.

[0047] In fact, during heating, the billet 10 expands and elongates. This expansion of the billet 10 is compensated for by automatically moving the second support and drive structure 27 of the second gripping means 16 (i.e., the second gripping arm 28 from the first gripping arm 22) away from the furnace 3. This is done automatically by adjusting the motor 3, which moves the second support and drive structure 27 toward and away from the furnace 3, to rotate at a constant torque. In this case, stresses (expansion during heating) on ​​the billet 10 in the second gripping arm 28 cause the motor 30 to overpower, allowing the second support and drive structure 27 (and the corresponding holding arm 28) to retract (move away from the furnace 3) while rotating at a constant torque. This allows the billet 10 to expand during the heating process while being held by the first and second holding arms 22 and 28, which prevent the billet 10 from rotating about its longitudinal axis.

[0048] Because the second gripping means 16 moves independently of the first gripping means 15 (moving on a surface member 25 connected to the beam 17), and the beam 17 of the first gripping means 15 moves in translation on the fixed base 2, the billet 10 can be optimally moved and positioned relative to each of the furnaces 3, and during heating the billet can not only be optimally supported while automatically compensating for elongation during the heating process, but also the billet can be held to prevent rotation about its longitudinal axis.

[0049] The driving means (electric motor 20) of the first gripping means 15 alternately moves the beam 17 on the fixed base 2 in two opposite directions along the longitudinal axis W while the furnace 3 is in operation, causing a kind of pendulum effect on the billet within the furnace 3 (without it flying out of the furnace). This effectively heats the billet, spreading the heating temperature inward along the billet, so that the billet can be heated evenly and homogeneously even if there are areas between the furnaces 3 that are not covered by the magnetic fields generated within each furnace.

[0050] 7-9 show the billet support 32 supporting each billet 10 before and after heating.

[0051] Preferably, two billets 10 are supported adjacent to but spaced apart from one another, with the first billet positioned along longitudinal axis W and the second billet positioned parallel to the first billet, as shown in Figures 1 and 3. Both billets are placed on corresponding platforms 35K and 35X supported by a rotating platform 36, such as platforms with semicircular receiving portions 35A as shown. In the illustrated embodiment, which is a non-limiting example, rotating platform 36 is integrally coupled to gear 37, which is driven by pinion or gear 38 driven by electric motor 39 supported on face member 40 below rotating platform 36.

[0052] Other actuators (linear, pneumatic, or hydraulic) 41 and 42 supported on the surface member 40 cooperate with the stands 35K and 35X to raise and lower the stands 35K and 35X. These actuators allow the stands 35K and 35X to be raised and lowered before and after the billet is heated.

[0053] For example, actuators 41 and 42, which are hydraulic jacks, can be used to move the stands 35K and 35X up and down depending on the temperature of the billet supported on each stand. a) When the billets are cool, position each of the cradles supporting the billets along its longitudinal axis W so that it is precisely aligned with the furnace 3. b) When the billet is hot (e.g., fresh from the furnace), it will expand (its diameter or cross section will increase), and the rack onto which the billet is transferred from the furnace must be lower than the longitudinal axis W to ensure that it receives the expanded billet.

[0054] Furthermore, the cradle that receives the billet before it is fed into the furnace may be in various positions (heights relative to the longitudinal axis W) depending on the degree of preheating that the billet has undergone.

[0055] Therefore, the actuators 41 and 42 serve as height compensation means for the respective pedestals 35K and 35X depending on the temperature of the billet both before it is introduced into the furnace 3 and when it is removed from the furnace.

[0056] As configured in this manner, billet support 32 is positioned by known lifting and handling means (not shown) so that billet 10 is positioned on first cradle 35K along longitudinal axis W and transferred into the furnace or furnaces (i.e., heating means) by first and second gripping arms 22 and 28. Meanwhile, a second billet (also mounted on billet support 32) is "ready to go" on billet support cradle 35X. Upon completion of the heating operation, electric motor 20 drives beam 17 of first gripping means 15 to remove the heated billet (which, in either case, is clamped by the gripping arms as described above) from furnace 3.

[0057] As a result, the heated billet is moved above the stand 35K, which has been lowered below the longitudinal axis W. Meanwhile, the electric motor 30 and the second gripping arm 28 move away from the billet placed on the stand. The height position of the stand 35K is lowered in accordance with the temperature of the billet.

[0058] Once the heated first billet is placed on cradle 35K, electric motor 39 is activated. Gears 37 and 38 cooperate to rotate turntable 36 180° to move the second billet (which is resting on cradle K) in the longitudinal direction W to a position where the first billet can be removed from system 1 according to the present invention. From this position, in a known manner, the first billet is removed from billet support 32 and a new billet is placed on cradle 35K for the next heat treatment following the heat treatment of the billet currently positioned along longitudinal axis W.

[0059] Thus, the system 1 according to the present invention operates in a substantially continuous cycle, minimizing downtime.

[0060] The billet support 32 is restrained to the fixed base 2 by a plurality of support columns 45 .

[0061] The system 1 according to the invention is able to operate the heating means or furnaces 3 to heat each billet in a well-controlled manner to the desired temperature (depending on the metallurgical properties, material and application of the billet), by means of a control unit of the system according to the invention which operates in response to detecting the "internal" temperature of the billet (the temperature near the axial center of the billet) and the temperatures at both ends 11A and 11B of the billet.

[0062] This also allows for a "temperature cone" to be created within the billet, where the temperature is higher at one end than at the other and decreases linearly as the temperature approaches the other end. The realization of such a temperature distribution (temperature cone) is also facilitated by the oscillating motion of beam 17 in two opposite directions along longitudinal axis W during the billet heating process.

[0063] To achieve this temperature control, the first and second gripping arms 22 and 28 are equipped with thermocouples 50 and 51 having electrodes 50A and 51A (see FIGS. 10 and 11). The electrodes protrude (preferably in a resiliently biased state) from the pre-contact ends 22A and 28A of the first and second gripping arms, respectively, and contact opposite ends 11A and 11B of the billet. These thermocouples 50 and 51 are located adjacent the longitudinal axis W of the first and second gripping arms. The thermocouples are connected to an electrical circuit (not shown) that transmits sensed temperature signals to the control unit described above.

[0064] When the first and second gripping arms 22 and 28 contact both ends of the billet, the electrodes 50A and 51A contact both ends 11A and 11B of the billet and dig into the metal. As the billet heats in the furnace 3, the metal softens and the electrodes (which are cone-shaped) penetrate into the metal, allowing for good temperature measurement near the axial center of the billet.

[0065] This temperature measurement allows the heating of the billet to be controlled, and the furnace 3 and the first and second gripping means 15 and 16 are appropriately adjusted to move the heated billet. The heights of the racks 35K and 35X, which receive the billet after removal from the furnace 3, relative to the longitudinal axis W are also adjusted according to the measured temperature.

[0066] It should be noted that the first end 3A of the heating means or furnace 3, which is the end adjacent the support for the billet 32, is provided with a detector for detecting non-coaxiality of the billet with respect to the furnace cavity 12 containing the billet. This detector prevents the billet from being introduced into the cavity 12 without being aligned with its longitudinal axis W, which could result in contact between the first end 3A and the billet resulting in damage to the first end 3A. Misalignment resulting from improper introduction of the billet into the cavity 12 can result in partial contact and / or improper heating of the billet (the billet 3 cannot be rotated about its longitudinal axis W when introduced into the furnace 3).

[0067] The detection device (see Figures 13 and 14) comprises a plurality of conductive tabs 80, made of metal or the like, attached to a ring that is also an electrical conductor and supported by a plurality of insulating bushings 82 fixed to the first end 3A of the furnace 3. The tabs have their free ends projecting toward the longitudinal axis W. The conductive ring is in turn connected to a regulated voltage supply (not shown) via a wire (also not shown) that is bonded to the conductive ring at 84.

[0068] When the metal billet is properly positioned along the longitudinal axis W, the free ends 83 of the metal tabs 80 define the maximum diameter of the billet toward the cavity 12 of the furnace 3. If the billet is not aligned with the cavity 12, the billet 10 will come into contact with one or more of the metal tabs, creating a short circuit between the contacted metal tabs and the furnace, which is detected by a mass detector (not shown) connected to the control unit of the system according to the present invention. In this case, the control unit stops the movement of the first and second gripping means 15 and 16 to prevent the billet from being introduced into the furnace. To this end, the control unit reverses the movement of the beam 17 carrying the first and second gripping means 15 and 16, moving the billet away from the first end 3A of the furnace.

[0069] Thus, the movement of the billet is properly controlled by the detection device shown in Figures 13 and 14 after the billet is clamped by the first and second gripping arms 22 and 28 and before the billet is taken into each furnace or heating means provided on the fixed base 2 according to the present invention.

[0070] Another control of the system 1 according to the invention, and in particular of each heating element or each furnace 3 according to the invention, is obtained by detecting the temperature distribution at the outer surface of the billet 10 (i.e., the "skin temperature") after the billet has been removed from the furnace. This evaluation allows controlling the heating of subsequent billets to improve the heating quality of the controlled billet.

[0071] To this end, the system 1 according to the invention comprises a structure 90 having a platform 91 supported by struts 92 and adapted to receive the billet 10 .

[0072] The billet is placed on the platform 91 by a known lifting and moving device in a known manner.

[0073] Pairs of thermocouples 96, configured to contact the surface of the billet at several points along the longitudinal axis of the billet, protrude from the inner surface 94 of the pedestal 91. The thermocouples include a plurality of electrodes 96A and 96B connected to a control unit of the system according to the present invention. Based on data detected by the thermocouples 96, the control unit measures the surface temperature and distribution of the surface temperature of the billet 10.

[0074] Based on the stored parameters, the control unit compares the stored temperatures with the current temperatures detected at several points on the billet, thus determining whether the temperature distribution is as desired or not for the type (material and size) of the heated billet checked, and then maintaining or modifying the heating parameters applied to the heating of the next billet to be subjected to heat treatment, i.e., keeping them the same as or modifying the heating parameters of the checked billet.

[0075] Based on the temperature detection by the structure 90, the control unit of the system according to the present invention can change both the heating power of each furnace 3 and the heating time of the billet, so that each furnace operates for the appropriate time, and move the beam 17 supporting the first and second gripping means 15 and 16, so that the billet can be moved in and out of the furnace 3 at the appropriate time.

[0076] The system according to the present invention as described above can be operated continuously in a fully automated manner, resulting in high production rates and good quality heated products (billets).

[0077] As described above, the system according to the present invention comprises a fixed base on which the first gripping means 15 moves, the first gripping means comprising a beam 17 movable directly on the fixed base and supporting a first support and drive structure 21 which supports a first gripping arm 22. The first gripping means 15 comprises second gripping means 16 supported by the beam 17 and movable on a face member 25 along a second guide 18A integrally connected to the face member 25. The second gripping means 16 comprises, in particular, a second support and drive structure 27 to which a second gripping arm 28 is connected.

[0078] The second gripping means comprises an electric motor 30 which moves the second gripping means along the second guide 18A along the face member 25 and therefore the first gripping means, which is a component of the face member 25, alone.

[0079] The first and second gripping arms 22 and 28 are configured to hold the billet 10 within the furnace 3. When a (metal) billet is heated by a rotating magnetic field that envelops the billet, the billet tends to rotate about its longitudinal axis. The first and second gripping arms 22 and 28 prevent this rotation, ensuring that the billet is heated.

[0080] Furthermore, if the second gripping means 16 is movable over the first gripping means 15 independently of the first gripping means, the second gripping member 28 can be moved relative to the first gripping arm 22 to compensate for any stretching or deformation of the billet during heating of the billet without having to release the billet from both gripping arms 22 and 28.

[0081] Relative movement between the second gripping means 16 and the first gripping means 15 can accommodate billets of any length.

[0082] Therefore, the present invention heats the billet while compensating for any deformation or elongation of the billet during heating, and in addition to metallurgical problems related to the crystalline structure of the metal that makes up the billet, it does not deform the billet so that it becomes unusable in the subsequent extrusion process, or damage any of the furnaces 3 or the components (gripping arms) of the first and second gripping means 15 and 16 that hold the billet.

[0083] Detailed embodiments and components of the present invention have been described above. It should be understood that the above-described system for heating a billet is presented by way of example. For example, the system for heating a billet may not include a component for measuring the temperature of the billet during heating and / or until downstream processing. The system of the present invention may include other components, such as a device for detecting the coaxiality of the billet with respect to the cavity of the furnace 3. The system 1 of the present invention may include only one electromagnetic induction heating component.

[0084] Such variations still have the structural features of the invention as set forth in the claims below.

Claims

1. A system for heating a metal billet (10), comprising: a fixed base (2) supporting at least one heating means or furnace (3) having a cavity (12) formed to receive a metal billet (10) during heating thereof, the fixed base being provided with a plurality of gripping means (15, 16) for holding the metal billet (10) during heating in the heating means (3), the gripping means (15, 16) being provided at first and second opposite ends (3A, 3B) of the heating means (3); the gripping means (15, 16) are movable relative to a fixed base (2) of the system, the first gripping means (15) comprising an elongated structure or beam (17) disposed below the fixed base (2) and the heating means (3); the beam (17) is movable while being guided along the fixed base, the beam (17) has a first end (17A) provided at the first end (3A) of the heating means (3) and is configured to cooperate with the first end (11A) of the metal billet (10), and supports a first gripping arm (22) connected to a first support and drive structure (21) fixed to the fixed beam (17); The first gripping arm (22) and the first support and drive structure (21) constitute the first gripping means (15); The beam (17) has a second end (17B) provided at the second end (3B) of the heating means, and supports a surface member (25) on which the second gripping means (16) is guided and movable; The second gripping means (16) comprises a second gripping arm (28) configured to cooperate with a second end (11B) of the metal billet and coupled to a second support and drive structure (27) of the second gripping means (16); The second support and drive structure (27) is movable while being guided by the plane member (25) supported by the beam (17) so as to move away from the first gripping arm (15) by the action of drive means (30, 31); the first and second gripping arms (22, 28) grip the metal billet so as not to rotate about its longitudinal axis (W) when the metal billet is placed in the heating means; the first and second gripping arms (22, 28) are relatively and automatically movable between each other and can move apart to compensate for deformation and elongation of the metal billet (10) while holding the billet (10) during heating of the billet in the heating means (3); A system characterized in that said gripping means (15, 16) are arranged coaxially with the longitudinal axis (W) of the cavity (12) of said heating means (3).

2. 2. The system of claim 1, wherein the beam (17) is movable along a first guide (18) provided on the fixed base, and the beam is moved along the fixed base by providing a rack (26) that cooperates with an actuator (20) integrally connected to the fixed base (2) or the beam (17).

3. 2. The system according to claim 1, wherein the face member (25) integrally connected to the beam (17) of the first gripping means (15) comprises a guide (18A) along which a second support and drive structure (27) of the second gripping means (16) moves, the movement being effected by an actuator (30) integrally connected to the second support and drive structure (27).

4. 4. The system of claim 3, wherein the actuator (30) is a constant torque controlled electric motor adapted to automatically move the second gripping means (16) away from the first gripping means (15) in accordance with the longitudinal elongation of the billet (10) during the heat treatment.

5. 2. The system according to claim 1, wherein the gripping arms (15, 16) are provided with members (50, 51) for measuring the temperature of a portion of the billet (10) adjacent to its axially central region.

6. 6. The system of claim 5, wherein the measuring members are thermocouples (50, 51) having electrodes (50A, 51A) protruding from the non-contact ends (22A, 28A) of the first and second gripping arms (22, 28) and cooperating with the corresponding opposing ends (11A, 11B) of the billet, the thermocouples being located near the longitudinal axis (W) of the heating means (3) and the gripping arms (15, 16).

7. 2. The system of claim 1, further comprising a plurality of billet supports (32) disposed between the first gripping arm (15) and the heating means, the supports (32) comprising a rotating table (40) supporting a plurality of cradles (35K, 35X) for a corresponding plurality of billets.

8. 8. The system according to claim 7, wherein the carriages (35K, 35X) are movable up and down relative to the longitudinal axis (W) of the cavity of the heating means (3), and means (41, 42) are provided for compensating the position of the carriages (35K, 35X) depending on the temperature of the billet (10).

9. 2. The system of claim 1, wherein a first end (3A) of the heating means (3) where the billet (10) is introduced into the cavity (12) is provided with an electrically conductive elongated member (80), the elongated member protruding from a support (81) provided at the first end (3A) of the heating means toward the cavity (12), the elongated member (80) defining an opening for introducing the billet into the cavity (12), the introduction opening being coaxial with the cavity, the support (81) being fixed to the first end (3A) of the heating means via a plurality of insulating bushings (82), and when the billet comes into contact with the elongated member, a signal is generated indicating that the billet (10) is not aligned with the cavity (12).

10. The system of any preceding claim, further comprising: means for detecting a surface temperature along said billet (70) after said billet has been heated.

11. 11. The system of claim 10, wherein the detection means comprises a structure (90) having a base (91) and supported by a load bearing member (92), the base configured to receive the billet after heating, and a plurality of thermocouples (96) projecting from an inner surface (94) of the base, the thermocouples configured to contact the surface of the billet at a plurality of locations along the longitudinal axis of the billet to measure the temperature of the surface of the billet.

12. 2. The system according to claim 1, characterized in that it comprises a unit for controlling the operation of the system, configured to control the movement of the gripping means (15, 16) and the activation of the heating means (3) depending on the temperature detected on the billet.

13. 2. The system of claim 1, wherein the billet (10) is comprised of a single piece or a plurality of pieces that are combined together longitudinally to form a structure (10) of a desired length, and in the latter case, the pieces are maintained in a longitudinally joined state by the gripping means (15, 16) during heating.

14. a base (2) supporting at least one heating means or furnace (3) having a cavity (12) formed to receive the metal billet (10) during heating thereof, the base being provided with corresponding first and second gripping means (15, 16) configured to hold the metal billet (10) during heating in the heating means (3), the first and second gripping means (15, 16) being provided at opposite first and second ends (3A, 3B) of the heating means (3); both the first and second gripping means (15, 16) are movable relative to the base (2) of the system, and the first gripping means (15) supports the second gripping means (16) such that the second gripping means (16) is movable on a face member (25) of the second gripping means; 2. A method for heating a metal billet using a system according to claim 1, wherein the first and second gripping means (15, 16) hold the billet (10) when the billet is introduced into the heating means (3), A method for compensating for deformation and elongation of the metal billet during heating, the compensation being achieved by performing automatic relative movement between the first gripping means (15) and the second gripping means (16) while maintaining the first gripping means (15) in a locked state on the base (2), the second gripping means (16) moving while being guided by a face member of the first gripping means (15), so that the second gripping means (28) accommodates the deformation and elongation of the billet without moving away from the billet.

15. 15. The method according to claim 14, characterized in that during the heat treatment in the heating means or furnace (3), the first gripping means (15) is moved on the base (2) alternately in two opposite directions along the longitudinal axis (W) of the billet (10), and this movement is performed while the second gripping means (16) remains fixed to the first gripping means (15), so that the movement of the first gripping means (15) causes the movement of the second gripping means relative to the furnace (3).

Images