EP0697930B1 - Device for controlling the motions of an ingot mold - Google Patents

Abstract

The invention relates to a method and device for controlling the oscillations of an ingot mold (1) in a continuous metal casting machine comprising a system (4) for generating oscillation motions of the ingot mold (1), along a guided trajectory, according to a predetermined motion law. According to the invention, the control member for the oscillation motions being adjusted for a preset primary speed law, the device comprises a means for the instantaneous correction of the displacement speed of the ingot mold, said speed being determined by said primary motion law so that the oscillation of the ingot mold during each cycle follows an optimum motion law adapted, at each moment, to the casting conditions.

Description

The present invention relates to a method and a device for controlling the movements of an ingot mold of a continuous casting assembly animated by reciprocating movements along a casting line.

The technique of continuously casting a molten metal to obtain a product such as a billet, a bloom or a slab has been known and used for a long time. In general, a continuous casting installation comprises an ingot mold or shell, consisting of a bottomless mold limiting a cavity open at its two ends and whose walls are cooled vigorously so that the molten metal poured into it upper orifice of the mold forms, along the cooled walls, a solidified crust having a sufficient thickness and metallurgical quality, at the level of the lower orifice, to allow the continuous evacuation of a product limited by said solidified crust and of which the central part which remains liquid gradually solidifies in a so-called secondary cooling device placed downstream of the mold, in the casting direction, and in which are placed, in addition, extraction means, for example rollers driven in rotation, which allow the product to be pulled down at an adjustable speed which depends on the casting conditions.

Generally, the mold has a substantially vertical axis and the secondary cooling device, which forms a corset for guiding the product, is curved so as to bring the horizontally cast product horizontally, to facilitate its evacuation and its cutting into sections of 'a certain length.

It is necessary to avoid adhesion of the metal on the cooled walls of the ingot mold which could cause defects such as cracks or tearing of the solid crust and, thus, favor breakthroughs or, at least, deteriorate the quality of the product. sunk.

This is why, from the start of the development of the continuous casting technique, it has been proposed to oscillate the ingot mold parallel to its rectilinear or curved axis. For this purpose, various well known devices are used. Generally, the mold is removably attached to a support and guide table, which is connected to an electro-mechanical, and / or hydromechanical guide and control assembly. The latter can be, for example, an eccentric system giving the mold a sinusoidal movement. Other oscillation systems, for example with cams or with hydraulic control, give wider possibilities for adjusting the oscillation movement and allow, for example, to produce a speed diagram of the sinusoidal, square, sawtooth type. Or other.

Depending on the period, the mechanical guide and oscillation assemblies have taken very diverse forms.

First of all, we can distinguish the guidance function and the oscillation function. The ingot mold table is maintained by guides which make it follow the desired path, and, on the other hand, is connected to actuators which give it an alternating movement of oscillation. One can for example use four actuators bearing on four points on the table and connected to a single motion generator.

It is also possible to guide and control the oscillations by means of the same assembly comprising for example an oscillation lever associated with rods for holding the mold on the desired path.

Eccentric or cam systems or hydraulic cylinder systems can be used to control the oscillations of the mold. Eccentric systems can act directly on the ingot mold support table or, via a connecting rod, on the lever which supports the ingot mold and, at the same time, gives it the oscillating movements.

When the oscillations are controlled by an eccentric, the law of motion has a sinusoidal shape. But one can also control the movement by means of a cam of desired shape which attacks the oscillation lever by a roller. In this case, the profile of the cam can be adjusted so as to obtain a determined movement law allowing, for example, to give the ingot mold a speed of ascent greater than the speed of descent and to unevenly distribute the duration of the cycles. product support and return.

Cylinder oscillation systems give still other adjustment possibilities making it possible, for example, to produce a speed diagram of the square, sawtooth or other type.

Furthermore, to avoid sticking of the solidified crust on the cooled walls, it is also necessary to lubricate them with a product capable of interposing between the crust and the wall, to promote sliding and improve the surface quality.

A liquid lubricant can be used in the case of free-jet casting, or else, in the case of a submerged nozzle casting, a powder which is poured onto the meniscus formed by the liquid metal at the top of the ingot mold and which melts in contact with the metal. It is advantageous to use products which, in addition to their lubricating power, fulfill the functions of a slag such as the absorption of inclusions.

The liquid slag thus formed in contact with the metal meniscus descends along the cooled walls of the mold, forming a thin film between the wall and the solidified crust.

This descent of the slag along the walls is favored by the cyclic movement of oscillation of the ingot mold which comprises, at each cycle, a phase of descent of the ingot mold and a phase of ascent in the opposite direction of the product which continues to descend. For a long time, we have known that it is interesting to regulate the oscillation movement of the ingot mold so that it reaches, at the end of the descent, a speed greater than the speed of extraction of the product, this which makes it possible to create a negative sliding effect for a certain period called "negative stripping time" or "healing time". It has been observed, in fact, that the liquid slag interposed between the cooled wall and the solidified crust is compressed for the duration of the negative sliding then decompresses, which promotes the infiltration of the lubricant.

This results, however, in the formation on the faces of the cast product of wrinkles or oscillation marks, the depth of which depends on the nature of the metal, but also on the casting conditions and, in particular, on the stroke and the frequency of the oscillations. as well as the duration of the negative slip.

In particular, experience has shown that increasing the frequency, for example in a range of 4 to 10 Hz, compared to the usual frequency of 1 to 3 Hz, decreases the importance of oscillation wrinkles.

On the other hand, we sought before, to achieve a negative stripping time TSN as long as possible and, consequently, a return time of the ingot mold, TP as short as possible for a time T0 of duration of the oscillation cycle given.

Now, following a more detailed analysis of the mold wall / product interface and skin formation phenomena, it is now estimated that the healing time must essentially be reduced and, for this purpose, use is made usually fairly high frequencies in conjunction with a reduced stroke, which also makes it possible to limit the inertial forces and the risks of vibration of the oscillation mechanism to values compatible with the behavior of the mechanical members. However, the infiltration of the lubricant is thus reduced, which increases the danger of sticking.

To improve the surface quality of the cast product, and in particular to minimize as much as possible the depth of the oscillation wrinkles, attempts have been made to act on certain parameters such as the frequency and the oscillation stroke or the duration of the stripping time in relation to the ascent time (EP-A-0.325.931).

However, the product extraction speed, i.e. the casting speed V _C cannot be kept constant or even limited to a narrow range. In fact, this speed already depends on the cross section of the product, small section billets being poured at speeds much higher than those which are accepted for products of larger dimensions such as blooms or slabs.

Furthermore, for the same product, it may be necessary, in modern installations, to vary widely the extraction speed during the casting process, for example during the replacement time of a bag, in the event of changes. product dimensions or for any other reason.

However, in the installations known up to now, the possibilities for adjusting the various parameters are limited, in particular in the most common cases where mechanical actuators of the connecting rod-crank type are used which limit the possibilities of adjustment.

The subject of the invention is a new method and devices which, on the contrary, allow the oscillation system of the mold to be operated by means of an interactive system which, taking into account the actuator in place in the installation. , will fix a motion law of the mold corresponding, optimally, to the casting conditions at all times.

Thus, while the known devices only made it possible in practice to act essentially on the stroke and the frequency of the oscillations, in retaining the general form of the law of movement, the invention provides a method and a device for controlling the movements of the mold making it possible to adapt the law of movement at all times to the casting conditions in order to maintain the quality of the product obtained.

In general, the invention therefore relates to a device for controlling the oscillations of a mold in a continuous metal casting machine comprising a mold mounted on a support, means for holding the mold on a substantially vertical trajectory and a system for generating an alternating oscillation movement of the ingot mold along said trajectory, comprising an actuator, a member for controlling a periodic movement of the actuator according to a determined law of movement and means for transforming the periodic movement of the actuator in a back-and-forth movement of the ingot mold, the law of movement of the actuator being fixed so as to determine the values of at least certain parameters of the movement of the ingot mold such as the amplitude of the oscillations, their frequency and the variation in the speed of movement of the mold up and down during each cycle.

According to the invention, the actuator and its control member being adjusted for a primary speed law fixed in advance, the device comprises a means for instantaneous correction of the speed of movement of the ingot mold determined by said law of movement primary so that the oscillation of the mold, during each cycle, follows an optimal law of motion adapted at all times to the casting conditions.

According to an essential characteristic of the invention, the speed variation means is a movement creation system according to an additional law which adds its action to the movement determined by the control member so that the law of movement resulting from the conjunction of the additional law with the primary law is optimally adapted to the casting conditions at each instant.

The invention can be applied, in particular, to any movement generation system in which the actuator consists, for example, of an eccentric or of a cam driven in rotation by an electric or hydraulic motor, by the 'through a transmission assembly. In this case, the speed variation means controls the drive motor or one of the elements of the transmission assembly, thanks to a movement creation system controlled according to a mathematical and knowledge law, making it possible to act on all parameters such as the frequency, the distribution of negative stripping and ascent times for each cycle, as well as the shape of the connections between these two phases of the movement. Preferably, the amplitude of the movement will be considered as a constant parameter for the chosen mathematical law.

On the other hand, according to an essential characteristic of the invention, the law of knowledge may evolve during casting, in an established or transient regime, to correct the effect of parameters which could modify the surface quality of the cast product.

According to the invention, different eccentric systems with different overall structures of ingot mold can be used. In a variant, the eccentric system consists of at least one group of two eccentrics arranged between the ingot mold support and the frame of the assembly, the two eccentrics being driven by the same drive shaft, which is connected to the motor by the movement transmission assembly.

In another variant, the eccentric system consists of at least one group of two eccentrics arranged between the ingot mold support and the frame of the assembly, one of the two eccentrics being driven by the motor with the transmission assembly movements, the other eccentric being driven by the first eccentric by means of a coupling rod.

In another variant, the eccentric system consists of at least one eccentric disposed between the ingot mold support and the frame of the assembly, the ingot mold support being carried by levers articulated on a support fixed on the frame of the assembly, the eccentric being driven by the engine with its transmission assembly.

In another variant, the eccentric system consists of at least one eccentric disposed between the mold support and the frame of the assembly, the mold support being carried by levers articulated on a support fixed to the frame, l the eccentric being connected to the control arm of one of the levers and being driven by the motor with its transmission assembly, the control arm being located on the other side of said lever relative to its articulation on the support fixed to the frame, and the eccentricity can be adjusted by a special device.

In another variant the eccentric system consists of at least one eccentric disposed between the ingot mold support and the frame of the assembly, the ingot mold support being carried by levers articulated on a support fixed to the frame of the together, said support being in two parts, a part fixed to the frame, and a mobile part hinging with respect to the fixed part by means of an actuating cylinder, the levers hinging on the mobile part, the eccentric being disposed between the control arm of one of the levers, and a base fixed to the frame, the control arm being disposed on the other side of said lever relative to its articulation on the movable part of the support; the eccentric being driven by the motor with its transmission assembly.

According to the invention, different systems with hydraulic cylinder (s) with different overall mold structures can be used. In a variant of the invention, the system with hydraulic cylinder (s) consists of at least two hydraulic cylinders arranged between the ingot mold support and the frame of the assembly.

In another variant, the system with hydraulic actuator (s) consists of at least one hydraulic actuator arranged between the ingot mold support and the frame of the assembly, the ingot mold support being carried by articulated levers on a support fixed to the frame of the assembly.

In another variant, the system with hydraulic actuator (s) consists of at least one hydraulic actuator arranged between the ingot mold support and the frame of the assembly, the ingot mold support being carried by articulated levers on a fixed support to the frame, the hydraulic cylinder being disposed between the control arm of one of the levers and a fixed base, the control arm being located on the other side of said lever relative to its articulation on the support fixed to the frame.

In another variant, the system with hydraulic actuator (s) consists of at least one hydraulic actuator arranged between the ingot mold support and the frame of the assembly, the ingot mold support being carried by articulated levers on a support fixed to the frame of the assembly, said support being in two parts, a part fixed to the frame, and a mobile part hinging with respect to the fixed part by means of an actuating cylinder, the levers s articulated on the movable part, the hydraulic cylinder being disposed between the control arm of one of the levers, and a base fixed to the frame, the control arm being disposed on the other side of said lever relative to its articulation on the mobile part of the support.

The invention can also be applied to a system for generating reciprocating movements comprising at least one hydraulic actuator associated with supply means determining an alternating movement of the actuator according to a periodic law. In this case, the speed variation means controls the supply of the hydraulic actuator from an additional law determined by a model or tables so as to adapt the periodic law of the actuator to the casting conditions at each instant.

The entire mold movement management system can operate automatically and includes temporary recovery means on order manual and means of final validation of corrections made manually.

The system can also operate in a closed loop and then includes self-checking means based on measurements made in situ.

According to a preferred embodiment of the invention, the control system comprises a model or tables for developing instructions corresponding to the casting conditions for obtaining optimum quality, a position sensor generating a signal measurement of the position of the ingot mold at each instant, a setpoint correction element receiving, on its various inputs, the setpoints developed by the model, the position measurement and setpoints or information relating to the product and all of the machine, and a regulating control member of the speed variation means from a position setpoint produced at each instant by the setpoint correction element.

In order to allow manual intervention at any time, the management system connects a set of manual corrections to the regulated command so as to act on said regulated command, having priority over the position setpoints generated by the correction element of instructions, which it neutralizes.

In addition, the setpoint correction element receives information and / or manual setpoints, which take precedence over the setpoints relating to the product or to the whole machine, which they neutralize.

In addition, in the management system according to the invention, the tables or the model are themselves managed by a self-adapting system, which permanently receives the position measurement of the mold, so as to take into account what has actually been achieved, and to adapt the values of the tables or the model in it or sending them from new instructions.

Advantageously, the auto-adapter system has an automatic immediate validation system, which can be interrupted and postponed at will by the operator.

In addition, a human-machine dialogue link, between the auto-adapter system and the tables or the model, makes it possible to capture the necessary information, and to send the chosen adaptations to the tables or the model.

The device for controlling the movements of an ingot mold according to the invention, as well as its management method thus have the advantage of having relative rise and fall times, which can be adapted at any time on demand, from so as to achieve the quality of the product to be obtained.

• La Figure l est une vue schématique de côté de la partie supérieure d'une installation de coulée continue, dont les mouvements alternatifs de la lingotière sont donnés par un système à excentrique.
• La Figure 2 est une vue analogue à la Figure l, l'installation étant munie d'un autre type de système à excentrique.
• La Figure 3 est une vue schématique de côté de la partie supérieure d'une installation de coulée continue comportant des leviers, et dont les mouvements alternatifs de la lingotière sont donnés par un système à excentrique.
• La Figure 4 est une vue schématique analogue à la Figure 3, d'un autre dispositif de système à excentrique.
• La Figure 5 est une vue schématique de côté de la partie supérieure d'une installation de coulée continue, dont les mouvements alternatifs de la lingotière sont donnés par un système à excentrique agissant sur un dispositif à levier.
• La Figure 6 montre deux exemples de courbes représentatives des mouvements de la lingotière.
• La Figure 7 est un diagramme représentatif des variations de la vitesse an cours d'un cycle d'oscillation.
• La Figure 8 est une vue schématique d'un dispositif de variation de vitesse selon l'invention, qui coopère avec le système de génération des mouvements alternatifs afin d'obtenir des temps relatifs de montée et de descente de la lingotière voulus.
• La Figure 9 est une vue schématique d'un autre mode de réalisation d'un dispositif de variation de vitesse selon l'invention.
• La Figure 10 est une vue schématique en perspective d'un autre mode de réalisation d'un dispositif de variation de vitesse utilisant un vérin hydraulique.
• La Figure ll est une vue schématique du système de gestion du dispositif de commande des mouvements d'une lingotière selon l'invention.
• La Figure 12 est une vue d'ensemble schématique d'une installation pour la mise en oeuvre de l'invention.

Other advantages will emerge from the invention, which will be better understood with the aid of the description given below of particular embodiments, described without implied limitation with reference to the appended drawings in which:

• Figure 1 is a schematic side view of the upper part of a continuous casting installation, the alternative movements of the mold are given by an eccentric system.
• Figure 2 is a view similar to Figure 1, the installation being provided with another type of eccentric system.
• Figure 3 is a schematic side view of the upper part of a casting installation continuous with levers, and whose alternative movements of the mold are given by an eccentric system.
• Figure 4 is a schematic view similar to Figure 3 of another eccentric system device.
• Figure 5 is a schematic side view of the upper part of a continuous casting installation, the alternative movements of the mold are given by an eccentric system acting on a lever device.
• Figure 6 shows two examples of curves representative of the movements of the ingot mold.
• Figure 7 is a representative diagram of the variations in speed during an oscillation cycle.
• Figure 8 is a schematic view of a speed variation device according to the invention, which cooperates with the system for generating reciprocating movements in order to obtain relative times of rise and fall of the desired ingot mold.
• Figure 9 is a schematic view of another embodiment of a speed variation device according to the invention.
• Figure 10 is a schematic perspective view of another embodiment of a speed variation device using a hydraulic cylinder.
• Figure 11 is a schematic view of the management system of the movement control device of a mold according to the invention.
• Figure 12 is a schematic overview of an installation for implementing the invention.

The control device according to the invention relates to the movements of an ingot mold, the assembly of which includes a system for generating alternative movements, associated with a holding system as well as a system for guiding the ingot mold, examples of which are are shown in Figures l to 5.

In these Figures 1 to 5, the system for generating reciprocating movements is constituted by an eccentric system which controls the support 2 of the ingot mold 1. This type of eccentric system is driven by a motor 4 with which it is connected by a 5 movement transmission set.

Generally, such an eccentric system is driven at a constant speed and therefore makes it possible to obtain a regular displacement of the ingot mold according to a sinusoidal movement as represented by curve A of FIG. 6, which shows the displacements of the ingot mold in function time.

It is interesting, however, to vary the distribution of the rise and fall times of the mold and we can use for this purpose cam or hydraulic cylinder systems, which allow to obtain, for example, a curve sawtooth like curve B in Figure 7.

The shape of this curve can be adapted to the need but, normally, is fixed once and for all by the movement generation system, in particular by the profile of the cam and one can, normally, only act on the frequency of the oscillations by varying the speed of rotation of the cam and, possibly, on their amplitude by acting on the motion transmission system.

In Figures 1 to 5, there are shown, by way of example, various known systems for controlling the oscillations of a continuous casting mold.

In the embodiment shown in Figure 1, the mold 1 is mounted in a support frame 2 associated with guides not shown which allow to maintain the axis of the casting cavity on a determined path, the assembly being animated a vertical back and forth movement by two eccentrics 10 mounted on a drive shaft 11 which is rotated by a motor 4, by means of a movement transmission assembly 5, the assembly being mounted on a support frame 3.

In the embodiment shown in Figure 2, the mold and its support frame 2 are driven back and forth by at least a group of two eccentrics 20 which are arranged between the support 2 of the mold 1 , and the frame 3 of the assembly. In this type of embodiment, one of the two eccentrics 20 'is driven by the motor 4 with the movement transmission assembly 5. The other eccentric 20 is driven by the first eccentric 20 by means of a coupling shaft 21.

When in this type of architecture, the system for generating alternative movements of the ingot mold l is constituted by a system with hydraulic cylinder (s), this system with hydraulic cylinder (s) consists of at least two hydraulic cylinders which are arranged between the support 2 of the ingot mold 1 and the frame 3 of the assembly in place of each of the eccentrics 20.

In the type of embodiment represented in FIG. 3, the system for generating the alternative movements of the ingot mold 1 is constituted by an eccentric system comprising at least one eccentric 30 disposed between the support 2 of the ingot mold and the frame 3 of the assembly . In this type of embodiment, the ingot mold is supported and maintained on its trajectory by two pairs of connecting rods 31 articulated, respectively, on two support pieces 2 of the ingot mold 1 and on a frame 32 fixed to the frame of the assembly. The oscillation movements are controlled by two eccentrics 30 integral in rotation and driven by the motor 4 by means of the transmission assembly 5. The eccentricity and therefore the amplitude of the oscillations can be adjusted by a device of known type.

In the case of FIGS. 1 to 3, the actuator which generates the reciprocating movements of the ingot mold is therefore an eccentric bearing directly on the support of the ingot mold, the latter being held in its path by guide means.

However, the guiding function can also be ensured by the movement generation system as, for example, in the case of FIG. 4 where the ingot mold is supported and maintained in its path by a pair of levers 41 and a pair of connecting rods 41 'articulated on the support 2 of the mold 1 and on a frame 42 fixed to the frame 3 of the installation.

Each lever 41 is extended beyond its articulation axis 44 by an arm 43 fixed at its end on a securing bar 46 on which the oscillation movement is applied. This is controlled, for example, by an eccentric or a cam 40, by means of a connecting rod 47.

An electric or hydraulic motor 4 rotates the eccentric 40 via a transmission assembly 5.

A similar system has been shown in the case of FIG. 5, the ingot mold being supported and maintained on its trajectory by a pair of levers 51 associated with holding rods 51 ′ and articulated around axes 57 on a frame 54 bearing on it on the frame 3. However, according to a particular arrangement, the frame 54 rests, in service, on a fixed part 53 secured to the frame 3 and can tilt around a fixed axis 52, under the action of a jack 55, so as to separate the entire upper part from the casting axis.

Figures 1 to 5 therefore schematically represent the arrangements usually used to generate oscillating movements of the mold along a guided trajectory and it will be seen that the invention can be adapted to all these embodiments.

Furthermore, in all the mechanisms shown in Figures l to 5, the movement generation system can be constituted by one or more hydraulic cylinders generally arranged in place of the eccentrics.

In general, the invention makes it possible to make instantaneous corrections to the speed of movement of the ingot mold determined by the oscillation control member by means of a speed variation device, which cooperates with the system of generation of alternative movements, so as to obtain relative climb speeds and lowering the mold which are adapted to the quality of the product to be obtained.

Figure 7 is a diagram showing, on the ordinate, the variation of the speeds of the ingot mold as a function of the time indicated on the abscissa.

The positive speeds correspond to an upward movement of the ingot mold and the negative speeds to a downward movement. During casting, the product descends at a negative speed Vc considered as constant on the diagram.

Curve (a) represents an oscillation cycle which takes place over a total time TO.

As indicated above, the movement is adjusted so that the speed of descent of the mold exceeds the speed of casting for a time TSN called "negative stripping time". During the remaining part of the cycle, which corresponds to the return time TP of the ingot mold, the latter moves upward relative to the product poured at the speed VC.

We can thus distinguish on the diagram the part AB corresponding to the negative slip at a lowering speed V1 faster than the casting speed, the part BC corresponding to the inversion of movement up to the rising speed V2 which is maintained for the CD part and finally the DE part which corresponds to the inversion of the movement until the mold finds itself at the speed of the product.

The duration TP of the BCDE part corresponds to the "return time" of the ingot mold.

We can therefore base, for a given installation, the conduct of the oscillation of the ingot mold on a motion law taking into account the frequency and the variations of the speed of the ingot mold which, for a given cycle time T0, condition the values of TSN and TP as well as the connection functions between these phases of the cycle.

Previously, it was sought to lengthen the negative stripping time TSN as much as possible, the return time TP being as short as possible for a given cycle time TO.

When the casting speed was increased, it was found that the TSN / TP ratio had to be reduced in order to maintain reasonable friction values.

In current systems, it is possible to vary the frequency of the oscillations, that is to say the period TO, as well as the travel of the ingot mold, that is to say the amplitude of the oscillations but, normally, the TSN / TP distribution is fixed by the movement generation system.

The invention, on the contrary, makes it possible to permanently correct the speed of movement determined by the primary motion law as a function of the casting conditions at the instant considered, so as to obtain an optimal motion law. Thus it is possible, without modifying the frequency, to adapt to the casting conditions the distribution of the relative times of ascent and descent of the ingot mold relative to the product, as indicated by the curve (b), modify the speeds of the ingot mold, as indicated by curve (c). But we can also modify the frequency, as indicated by the curve (d).

More particularly advantageously, the invention allows, taking into account the characteristics of the motion generation system which determines the primary motion law, to add thereto an additional motion law defined by an auxiliary system for creating movements from a model or tables allowing to take into account, interactively, all the casting conditions at the time considered.

In cases where the system for generating alternative movements consists of an eccentric system, as in the examples shown in Figures 1 to 5, this eccentric system cooperates with the speed variation device from instructions developed by a model or tables referenced MM, which controls the motor 4 or one of the elements of the transmission assembly 5, as shown schematically in Figures 8, 9 and 10.

In Figure 8, there is shown schematically the mold 1 driven by the motor 4 by means of a transmission assembly 5 of movements. In this type of embodiment, a model or MM tables directly controls the motor 4, so as to have the relative rise and fall times of the ingot mold adapted exactly to the quality of the product to be obtained.

In another embodiment shown in FIG. 9, the movement transmission assembly 5 comprises an epicyclic train 61. This epicyclic train 61 is constituted by a ring 62 which meshes with satellites 64. These satellites 64 in turn mesh with a sun gear or sun 63. The satellites 64 are mounted idly on a planet carrier 65. The main motor 4 drives a pinion 66 which meshes with an outer ring 67, integral with the ring 62 of the planetary gear. An auxiliary motor 60 drives the sun gear or sun 63, and the planet carrier 65 is connected to the mold 1 by the eccentric system. In this type of embodiment, it is the auxiliary motor 60 which is controlled by the model or the tables MM. In this type of device, there is thus the sun gear or sun 63 which is regulated in speed, while the crown 62 rotates at constant speed being driven by the main motor 4, this assembly makes it possible to vary the output speed on the door -satellites 65 at the exact desired value. A variant of the invention can be done by controlling the main motor 4 by means of the model and / or the MM tables, according to the speeds to be obtained and the mechanical forces to be supplied.

A variant of this device shown in Figure 9 is the object of Figure 10. In this embodiment, the sun gear or sun 63 is driven by a hydraulic cylinder 68, which is itself controlled by the model or the MM tables , so as to vary the output speed on the planet carrier 65, in order to obtain the relative rise and fall times of the mold, which are required to obtain the quality of the desired product.

In all types of embodiment where the system for generating alternative movements of the mold is driven by a motor 4, this main motor 4 can be a hydraulic motor. Likewise, in the types of embodiment in which an auxiliary motor 60 is used, this may be a hydraulic motor.

Figure 11 is a diagram of a management system according to the invention for managing at any time the position of the mold l, by the control device, by means of a model or MM tables, which sends its instructions to a CC setpoint correction element. The correction element of setpoints CC permanently receives the position measurement MP from the mold 1 by means of a position sensor CP, as well as the setpoints or information ID relating to the product and to the machine. The setpoint correction element CC then acts on the regulated command SP of the mechanical or hydraulic system for positioning the ingot mold, by sending the position setpoint P at any time.

In addition, according to the invention, the management system has a set of manual corrections CM, which is connected to the regulated control SP of the mechanical or hydraulic system for positioning the ingot mold l. This set of manual corrections CM acts on the regulated command SP, so as to have priority over the position setpoints P generated by the setpoint correction element CC, which this set neutralizes.

The setpoint correction element CC also receives information and / or manual setpoints ICM, which take precedence over the setpoints or information ID, which they neutralize.

Advantageously, the system also includes an SAD autoadapter assembly, which permanently receives the measurement of positions MP from the ingot mold l and makes it possible to take into account what has actually been done to modify the values of the tables or of the MM model, so as to develop new instructions better suited to the casting conditions observed.

In addition, according to the management method of the invention, the SAD autoadapter system has an immediate and automatic validation system V, which can be interrupted and deferred at will.

Finally, a human-machine dialogue D connection can be provided, between the SAD autoadapter system, and the tables or the MM model, so as to capture the necessary information, and to send the chosen adaptations to the tables or the MM model.

Figure 12 schematically shows, by way of example, the entire system for controlling the movements of an ingot mold 1 mounted on a support 2, the oscillations of which are controlled by an actuator of the type described in Figures 1 to 4, example an eccentric or a cam 10 driven by a motion generator 4 such as an electric motor. The latter can be driven at a constant speed which determines the frequency of the oscillations whose amplitude depends on the characteristics of the mechanical transmission system.

The motor 4 thus defines a law of primary sinusoidal or sawtooth movement, as indicated in FIG. 6.

According to the invention, the speed of rotation of the motor 4 determined by the primary motion law is corrected, without modification of the initial settings, by an automatic management system comprising a calculator 7 of the parameters of the final motion law which must follow the ingot mold according to the casting conditions.

These conditions are defined by tables 71 taking into account, in particular, the characteristics relating to the cast product (steel grade, product format, the race of the ingot mold, the characteristics relating to the casting in progress (casting speed, powder coverage, production, etc.) under the established regime and under the transitional regime.

A command 72 makes it possible to display on the computer 7 the parameters corresponding to the choice of the operating mode taking into account the state of the law of motion of the engine 4 displayed by a control system 73, 74.

From the essential parameters determined by the computer 7, in particular the frequency and the TSN / TP ratio, a function generator 75 draws up the instructions corresponding to the motion law which the ingot mold must respect at the instant considered and which are displayed on the supply 76 of the motor 4 to correct the speed of the latter.

A system 77 for controlling the behavior of the ingot mold makes it possible to measure at all times the characteristics of the casting such as the casting speed, the frequency, the stroke, the level of metal, the consumption of powder, the friction, etc. .

All of the information is collected by a processing system 78 and a recorder 79 makes it possible to verify all of the operation and, in particular, the anomalies.

The reference signs inserted after the technical characteristics mentioned in the claims, have the sole purpose of facilitating the understanding of the latter, and in no way limit their scope.

Claims (23)

1. Device for controlling the oscillations of an ingot mold in a continuous metal casting machine comprising an ingot mold (1) mounted on a support (2), means (3) for maintaining the ingot mold (1) on a substantially vertical trajectory and a system for generating an oscillatory alternate motion of the ingot mold (1) along said trajectory, comprising an actuator (5), a member (4) for controlling a periodic motion of the actuator according to a motion law and means (10, 20) for transforming the periodic motion of the actuator (5) into a to-and-fro motion of the ingot mold (1), the motion law of the actuator (5) being fixed so as to determine the values of at least some of the motion parameters of the ingot mold (1) such as amplitude of oscillations, their frequency and the variation in the upward and downward speeds of displacement of the ingot mold (1) during each cycle,
      characterized in that the actuator (5) and its control member (4) being adjusted for a preset primary speed law, the device comprises a means (CC) (75) for instantaneously correcting the displacement speed of the ingot mold (1) determined by said primary motion law in such a way that the oscillation of the ingot mold (1) during each cycle follows an optimum motion law adapted, at each moment, to the casting conditions.
2. Control device according to claim 1, characterized in that the speed varying means is a system (60) (75) for creating motion according to an additional law which adds its action to the motion determined by the control member (4) in such a way that the motion law resulting from the conjunction of the additional law with the primary law is adapted in an optimum way, at each moment, to the casting conditions.
3. Control device according to one of claims 1 and 2, characterized in that the actuator (10, 20) of the motions of the ingot mold being driven in rotation by a motor (4) via a transmission system (5); the speed variation means pilots the motor (4) or one of the elements of the transmission system (5) from a mathematical model or tables defining an additional motion law.
4. Control device according to claim 2, characterized in that the transmission system (5) of the motions comprises an epicyclic train (61), the crown (62) of which is driven by the main motor (4), and whose motion is collected on the satellite carrier (65) to drive the eccentric system, the planet wheel (63) being driven by an auxiliary motor (60) piloted by the model or tables (MM).
5. Control device according to claim 3, characterized in that the main motor (4) and/or the auxiliary motor (60) is a hydraulic motor.
6. Control device according to claim 3, characterized in that the planet wheel (63) is driven by a hydraulic jack (68) piloted by the model or tables (MM).
7. Control device according to any one of claims 2 to 5, characterized in that the eccentric system is made up of at least one group of two eccentrics (10) arranged between the support (2) of the ingot mold (1) and the frame (3) of the overall assembly, the two eccentrics (10) being driven by the same drive shaft (11), which is connected to the motor (4) via the motion transmission system (5).
8. Control device according to any one of claims 2 to 5, characterized in that the eccentric system is made up of at least one group of two eccentrics (20) arranged between the ingot mold (1) support and the frame (3) of the overall assembly, one of the two eccentrics (20) being driven by the motor (4) with the motion transmission system (5), the other eccentric (20) being driven by the first eccentric (20) by means of a coupling rod (21).
9. Control device according to one of claims 2 to 5, characterized in that the eccentric system is made up of at least one eccentric (30) arranged between the ingot mold (1) support and the frame (3) of the overall assembly, the ingot mold (1) support being supported by levers (31) articulating on a support (32) fixed onto the frame (3) of the overall assembly, the eccentric (30) being driven by the motor (4) with its motion transmission system (5).
10. Control device according to any one of claims 2 to 5, characterized in that the eccentric system is made up of at least one eccentric (40) arranged between the ingot mold (1) support and the frame (3) of the overall assembly, the ingot mold (1) support being supported by levers (41) articulating on a support (42) fixed onto the frame (3), the eccentric (40) being connected to the control arm (43) of one of the levers (41) and being driven by the motor (4) with its motion transmission system (5), the control arm (43) being situated on the other side of said lever (41) in relation to its articulation (44) on the support (42) fixed to the frame (3).
11. Control device according to any one of claims 2 to 5, characterized in that the eccentric system is made up of at least one eccentric (50) arranged between the support (2) of the ingot mold (1) and the frame (3) of the overall assembly, the support (2) of the ingot mold (1) being supported by levers (51) articulating on a support (52) fixed onto the frame (3) of the overall assembly, said support (52) being in two parts, one part (53) fixed onto the frame (3), and one mobile part (54) articulating in relation to the fixed part (53) by means of a control jack (55), the levers (51) articulating on the mobile part (54), the eccentric (50) being arranged between the control arm (56) of one of the levers (51), and a base fixed onto the frame (3), the control arm (52) being arranged on the other side of said lever (51) in relation to its articulation (57) on the mobile part (54) of the support (52), the eccentric (50) being driven by motor (4) with its motion transmission system (5).
12. Control device according to one of claims 1 and 2, characterized in that the alternate motion generating system comprises at least one hydraulic actuator (4) associated with supply means (76) determining an alternate motion of the actuator (4) according to a periodic law, and in that the means (75) for varying speed pilots the supply (76) of the hydraulic actuator from an additional law determined by a model (MM) (7) or tables (71) in such a way as to adapt the periodic law of the actuator (4) to the casting conditions at each moment.
13. Control device according to one of the preceding claims, characterized in that it can function automatically and comprises means (CM) for temporarily reassuming manual control and means (V) for definitively validating manually made corrections.
14. Control device according to one of the preceding claims, characterized in that it operates in closed-loop mode and comprises means (SAD) for self-checking using measurements taken in situ.
15. Control device according to claim 14, characterized in that it comprises a model or tables (MM) for generating reference values corresponding to the casting conditions in order to obtain optimum quality, a position sensor (CP) generating a measurement signal (MP) of the position of the ingot mold at each moment, a reference value correction element (CC) receiving, on its different inputs, the reference values generated by the model (MM), the position measurement (MP) and reference values or information (ID) relating to the product and to the overall assembly of the machine, and a member (SP) providing regulated control of the speed variation means from a position reference value (P) generated at each moment by the reference value correction element (CC).
16. Management method of a control device according to claim 15, characterized in that the reference value correction element (CC) receives information and/or manual reference values (CM) which have priority over the reference values or information (ID), which they inhibit.
17. Management method according to claim 16, characterized in that a manual correction assembly (CM) is connected to the regulated control (SP) in a manner so as to act on said regulated control (SP), by having priority over the position reference values (P) generated by the reference value correction element (CC), which this assembly inhibits.
18. Management method according to claim 17, characterized in that the tables or the model (MM) are themselves managed by a self-adapting system (SAD), which permanently receives the position measurement (MP) of the ingot mold, in such a way as to take into account what was actually carried out, and to adapt the values of the tables or model (MM) by sending them/it new reference values.
19. Management method according to claim 18, characterized in that the self-adapting system (SAD) comprises an automatic immediate validation system (V), which can be interrupted and deferred by the operator as and when required.
20. Method according to any one of claims 18 and 19, characterized in that it organizes a dialog link (D) between man and machine, i.e. it sets up a link between the self-adapting system (SAD) and the tables or model (MM), so as to capture the information required, and to send the chosen adaptations to the tables or model (MM).
21. Method for controlling the oscillations of an ingot mold in a continuous metal casting machine comprising an ingot mold (1) mounted on a support (2), means for maintaining the ingot mold (1) on a substantially vertical trajectory and a system for generating an oscillatory alternate motion of the ingot mold along said trajectory, comprising an actuator (5), a member (4) for controlling periodic motion of the actuator according to a motion law and means (10, 20) for transforming the periodic motion of the actuator (5) into a to-and-fro motion of the ingot mold (1), the motion law of the actuator being fixed so as to determine the values of at least some of the motion parameters of the ingot mold (1) such as amplitude of oscillations, their frequency and variation of upward and downward speeds of displacement of the ingot mold during each cycle,
       characterized in that, the actuator (5) and its control member (4) being adjusted by a preset primary speed law, the instantaneous displacement speed (V) of the ingot mold (1) is permanently corrected according to the casting conditions at the considered moment of each cycle so as to define, at each moment, an optimum motion law of the ingot mold (1) in which the relative upward (TP) and fall times (TSN) of the ingot mold (1) in relation to the product are adapted to the quality of the product to be obtained.
22. Control method according to claim 21, characterized in that an additional motion law defined by a system for creating motion from a model or tables (MM) taking account of casting conditions at the considered moment is added to the primary motion law determined by the control member (4).
23. Control method according to one of claims 21 and 22, characterized in that the additional law is made to evolve during casting to correct the effect of at least one of the parameters liable to modify the surface quality of the cast product, in such a way as to obtain optimum quality.

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