PROCEDURE AND DEVICE FOR MANUFACTURE OF STEEL OF STRING COLADA
FIELD OF THE INVENTION The invention relates to a process for the manufacture of strand cast steel products or extrusion, where the process presents a step of forming the fluid core of the casting product. It also relates to a device for the casting of steel rope or extrusion including an ingot mold, means for the conduction in the form of an arch and support of the extracted rope as well as means, which are disposed along the path of the casting. rope and are movable together, to make a small deformation of the product of the laundry. Such a small deformation is also known under the softreduction concept "softreduction". BACKGROUND OF THE INVENTION In the rope casting, the cast rope is solidified continuously through the formation of a solid rope shell in the ingot mold, and then in the direction of the center of the cord to solidify during the extraction process. This is presented on the solidification front by concentrating the alloying elements. This causes refinements in the core of the cord that solidifies transversely, which later on show unequalities and unequal properties in the cross section of the rope. In order to positively influence the solidification process, electromagnetic agitation is known, where the melt receives a current movement. An agitation in the secondary cooling zone or in the final zone of a rope casting apparatus must cause a succession of globulitic solidification and avoid the refining of the core. As another means to prevent refining in the solidification front and the increase in core density, soft reduction is used, in which a light lamination of the cord not yet completely solidified through is practiced, and with this the nucleus is still fluid. EP 0 603 330 discloses a method for the production of square ingots and blocks of steel products cast in rope or extrusion with a step of forming the core of the cast product. This step of formation or deformation is carried out in an area, in the path of the winding of the rope between the point, in which there are still no solidified regions and the point, in which the product is located, an area that is between These points correspond to a concentration of the solid nuclei inside the fluid core from 10% to 80%. For this purpose, a device is proposed, which includes internal and external segments of an arc-shaped roller passage section. The segments that remain inside the side of the arch are movable in comparison with the outer segments. perpendicular to the rollers of the segments there are additional rolls of roller cages, which are also pressed in the direction of the casting axis. In addition, the swamp or sediment that adjusts long and thin to more porosity and refinements is conducted in the fast casting process. This limits due to the poor quality, an advantage of the advantages of fast casting. SUMMARY OF THE INVENTION The present invention basically proposes the task of preparing a method and a device for the manufacture of cast products with homogeneous properties through the cross section of the cord especially preventing refinement with a simultaneous increase in density of the nucleus. The procedure and the device must also be able to be used in installations with high casting speeds and casting formats adapted to the final format. This task is solved by a method with the features of claim 1 and a device with the features of the claim. Advantageous conformations are presented in the dependent claims. The basic thought of the invention is a regulation procedure, in which a tensile force of the rope is used as a control variable for adjusting the position of the swamp tip or solidification front point in proportion to the position of a pair of rollers that perform the deformation and with that of the separation of the rollers along the trajectory or runway of casting of rope, to ensure that the swamp tip is always directly in the separation between the rollers, that is, the rope solidifies directly in the area between both rollers and with this during the training step. The pulling force of the rope is a quantity that depends on the pre-set adjustment force of the rolls, the thickness of the deformation and a characteristic value of the working material. The nominal value is the pulling force, which occurs if the swamp tip is directly in the gap between the rollers. With the deviation of the present value from the nominal value, the desired ratio between the position of the tip of the swamp and the separation of the rolls in a first embodiment can be adjusted by varying the casting speed and in a second embodiment by varying the position of the pair of rollers to the rope. In a third embodiment it is proposed that the ratio between the position of the tip of the swamp and the recess of the rollers as well as the parameters of the casting speed as well as the running capacity of the rollers be adjustable along the trajectory of the wash of rope. As a whole, a variation of the solidation position is automatically recognized and corrected, for example, by variation of the casting temperature due to overheating or by variation of the solid temperature, after a fine-tuning of the alloy, of the adjustment procedure. With respect to the device, it is proposed that the diameter of the rollers be between 400 and 1800 mm. The selection of a larger roller diameter in proportion to the usual diameters of the driving rollers is achieved in proportion to the flat angle of adjustment and for the pressed length an optimum soft reduction, and a variation of the easily recognizable tensile force. Furthermore, the pressed length with safer flat adjustment angle is presented in a backward displacement of simultaneously larger volume, and the decrease in volume in the final solidification is compensated by the backward movement of the still fluid core. This advantage is not reached safely in soft reduction systems with multiple pairs of rollers according to the current state of the art. Furthermore, it is not excluded in multi-roll systems that a final solidification is achieved between two pairs of neighboring rollers, which produces a normal final solidification without soft reduction. The device for the selection of larger roller diameter can cause a large reduction of the thickness of the rope with only one pair of rollers, which in the practical area of operation can present a reduction of 12 to 15 mm, without causing the rope internal damage. The extension in the solidification front is negligible thanks to a soft reduction setting. The diameter of the roller determines the slope of the soft reduction zone and with this the limits of extension and the degree of compression. Downstream of the rope behind the pair of rollers is arranged a pair of drive rollers, by whose torque the value of the tensile force of the rope is determined. BRIEF DESCRIPTION OF THE FIGURES Other features and advantages of the invention are apparent from the following description. Figure 1 shows a first embodiment of the device according to the invention with a roller pair stationary along the path or track of the rope casting; Figure 2 the embodiment of the device according to figure 1 with a second pair of stationary rollers, operable at will; Figure 3 a second embodiment of the device according to the invention with a pair of movable rollers along the rope casting path, which is disposed downstream of the rope before a directional zone; Figure 4 the embodiment of the device according to figure 3 with a pair of movable rollers along the rope casting path, which is disposed downstream of the rope behind the steering zone; Figure 5 a schematic representation of the process according to the invention in combination with a pair of drive rollers; Figure 6 a side view of the device with a pair of rollers and a pair of drive rollers; Figure 7 is a view along section A-A of the device according to Figure 6;
Figure 8 is a view along section B-B of the device according to Figure 6; Figure 9 a section in cross section of the device with transport rails; Figures 10, a, b a schematic view of the pair of rollers with two roller diameters of different sizes. DETAILED DESCRIPTION OF THE INVENTION Figures 1 to 4 show different arrangements of the first and second embodiments of the device according to the invention. In FIG. 1, a rope casting device 1 is very simply shown, which essentially includes an ingot mold and an arc-shaped rope casting path. The rope casting path 3 is usually composed of a cooling zone 4 and a traction and directional zone 5 connected to the previous one. According to the invention, the soft reduction process is not applied by means of a multiplicity of knee pairs or roller cages, but only by a pair of stationary rollers 6, which are composed of an upper roller and a lower roller 7, 8 respectively. Downstream is behind the pair of rollers 6 arranged to reduce a pair of drive rollers 9 for steering with an upper and a lower drive roller 10 and 11. The corresponding equipment of the rollers 12, 13 are shown strongly simplified. In FIG. 2, corresponding construction parts are provided with identical reference figures. Beside a first pair of rollers 6 and a pair of drive rollers 9 a second pair of rollers 14 with a corresponding pair of drive rollers 15 is disposed before the first stationary pair of in the casting path by rope or extrusion. By means of the variation of the speed of casting it is possible to regulate the formation of the swamp tip in the string and with this the objective is reached, that the solidification through the string always takes place in the recess or separation between the rollers, to achieve optimal core compression and avoid core refinements. In two pairs of rollers it is selectively possible to carry out in the first pair or in the second pair a soft "soft-reduction" reduction of the swamp tip, where the lower roller of the pair 20 can selectively exist. The second embodiment of the invention is explained by means of Figures 3 and 4. It is a pair of rollers 16, which together with a pair of corresponding drive rollers 17 is movable along the casting path of rope. Such a variation of position is indicated with the pair of rollers 16 f and 17.
Downstream of the rope is arranged behind the pair of rollers 16 a directional zone 18. Which is composed of two pairs of drive rollers 19 and 20. Figure 3 shows this embodiment with a pair of movable rollers 21, which it is arranged behind the directional zone 18. With 21 'the displaced pair of rollers is indicated. The path of movement according to the invention is controlled in dependence on the pulling force of the rope. It also depends on the speed of the laundry. With a low casting speed a lower traffic path is reached (Figure 3) and with a high casting speed the traffic path is greater (Figure 4). The regulation procedure in combination with a. The pair of driving rollers 2 is shown schematically in Figure 5. A pair of rollers 23 is arranged in a rope casting product with the outlet thickness DI and the reduced thickness D2. The pair of rollers adjusts either to a nominal thickness or to the distances of the pieces. Both the upper roller and the lower roller 24, 25 of the soft reduction rollers are adjustable with respect to their adjustment force and their travel, shown here schematically. The necessary force Z for the extraction of the rope is calculated by means of the adjustment force P, the thickness difference as well as a characteristic value of the working material and the necessary torque for the rollers 27, 28 of the subsequently connected impeller 22. Here the nominal value of the extraction force or traction, which occurs, if the marsh tip S or the solidification end is directly in the recess of the two rollers 24, 25. In a deviation between the current value and the nominal value is a correction of the placement ratio between the roller pair and the swamp tip, either by variation of the casting speed or by variation of the position of the pair of rollers 23 Figure 6 makes clear how is the structure of such soft reduction equipment - soft reduction - in a side view. The soft reduction and the pair of driving rollers 23 and 22 are arranged in a frame of common equipment 29. The regulation of the path or path and the force of the pair of rollers 23 is carried out by two hydraulic cylinders 32, 33 acting on the shafts of rollers 30 and 31, which is indicated by the sectional view AA of Figure 7. With 34 the production of rope casting or extrusion is indicated, with the core zone pressed together between the two rollers 24 and 25. Figure 8 shows the sectional view BB of Figure 6. The adjustment of both driving rollers 27 and 28 is carried out by means of the two cylinders 36 and 37. The rollers 27 and 28 are provided with respective driving means 38 and 39 whose driving moment a serves as a measure for the extraction force Z. According to the second embodiment, the equipment frame 29 is passable with the pair of driving rollers 23 and 22 along the casting path of rope or continuous. This is achieved according to Figure 9 preferably by means of running wheels 40, 41 which are disposed on both sides of the equipment frame 29. There are transit rails 42, 43 along the casting path, in which run the marching wheels in combination with the equipment frame. The representation of a roller with a diameter of 400 mm and a roller with a diameter of 1500 mm is clarified by means of FIGS. 10 a and 10 b, which with the help of the rollers in a large proportion makes controlled core compression possible. According to the formula Td = (d / 2 * increment h) with Id = pressed length, d = diameter and increment h = decrease of thickness, it can be seen that with an equal increase h, the pressed length increases and the angle of fit a. through the pressed length it becomes smaller. A longer pressed length and a smaller angle or. they mean a flatter adjustment angle and with this a small expansion in the solidification front and a longer reduction section. This advantageously acts in the compression of the core. A satisfactorily adjusted core compression is possible with rollers with a diameter between 400 and 1800 mm. With the aid of the proposed method and device, both blocks and square ingots can be subjected to a soft reduction, in particular they can be profiled, rectangular, quadratic or round cords compressed in the core. The described device can be installed in new installations, but it is also possible to equip existing installations with the same.