MXPA96001883A - Vertical draining line for lingo - Google Patents

Abstract

The present invention relates to a pouring line for emptying an ingot, comprising a mold, a set of container elements located at the outlet of the mold, a plurality of container and guide assemblies that are immediately downstream of the assembly. Container elements and comprising a plurality of pairs of rollers associated with a vertical segment of the line, a stretch assembly associated with a horizontal segment of the line, wherein the container and guide assemblies cover at least the entire vertical segment of the line. the emptying line downstream of the set of container elements, and operating means regulated by a data processing unit to adjust at least the position of the rollers of the container and guide assemblies with respect to the ingot to obtain a Rolling controlled at least in the downstream part of the vertical segment of the empty line

Description

VERTICAL DUMPING LINE FOR INGOTS This invention relates to a vertical emptying line for ingots, and in particular, for thin and medium sized ingots, as set forth in the main claim. To be more precise, the invention relates to an improved vertical emptying line, which makes possible an increase in the versatility of the plant and, at the same time, improves the internal and superficial quality of the emptied product. The state of the art covers the continuous emptying plants previously configured with a vertical emptying line to empty ingots continuously and, to be more precise, to empty thin and medium sized ingots. The state of the art most developed in this field is shown in Figure 1. The continuous dump machines 100, of the state of the art, comprise a mold 101, which acts as a former for the emptied product 108, and is associated downstream with a set of lower rolls 102, which contain the emerging product 108. The height "a" of the mold, depending on the type of product, in the material parameter and in other working parameters, is, for example, approximately 1,000 to 1,400 mm. , while the height "b" of the lower roller assembly 102 is approximately 600 to 800 mm.

The lower rollers can be replaced with plates or other container elements that have the same purpose. Downstream of the lower roller assembly 102, a plurality of container and guide assemblies 103 are included in sequence, each of which comprises stationary rotating rolls 104, generally of small diameter and capable of limiting the product 108 laterally during its descent. and progressive solidification. The container and guide assemblies 103 normally cooperate with secondary cooling means that accelerate the completion of the solidification process of the emptied product 108.

In the example shown, the container and guide assemblies 103, as a whole, cover a height "c" of approximately 5200 to 5600 mm. An extraction assembly 105, which is commonly of a type of main roller, is included in extension of the container and guide assemblies 103, in the vertical segment of the emptying line; the rollers of the extraction assembly 105, grip with a given pressure the empty product 108, and accompany it in the curvature with which the product takes a substantially horizontal trajectory. The height "e" of the extraction assembly 105 is, in the example shown, from about 3600 to 4000 mm.

A stretch assembly 106 is located in the horizontal segment of the pour line, which normally coincides with the rolling plane, and delivers the product to a station 107 to cut it to size and to the successive processing stations. The total height T of the emptying line to the rolling plane is approximately 10400 to 1 1800 mm. The current continuous vertical pouring technologies for the production of ingots serve to bring the solidification of the product 108 to a very high value before the end, at or near the end of the container and guide 103 assemblies. Thus, there is a marked reducing the risk of thickening of the crust of the ingot 108 due to the inclusion of a free segment of a height "d" of about 300 to 500 mm. between the container and guide assemblies 103, and the extraction assembly 105, and the action of the rollers of the extraction assembly 105, in the ingot 108 and to the hydrostatic pressure exerted by the liquid core. Continuous emptying machines of the state of the art, such as the machine 100 of Figure 1, do not provide the position of the contact point, that is, the area where the two solidified crusts begin to be welded together, to be able to be made variables and be conditioned in a desired way by a controlled variation of the emptying parameters.

In such machines of the state of the art, the position of the contact point is the natural one and depends substantially on the type of cast steel, so that, since equal materials are emptied, the point of contact is located at approximately a substantially fixed point. . Instead, the present applicants have investigated for a time now (see EP-A-0625388) that, in order to have a good quality cast product, particularly with thin ingots, it is necessary that the longitudinal position of the contact point it can be varied, even continuously, by controlling and possibly altering the emptying parameters continuously. In this way, depending on the type of steel cast, it is possible to vary the longitudinal position of the contact point in order to achieve the best result. EP-A-0625388 also teaches the adjustment of the position and speed of the rollers of the container and guide assemblies 103, in accordance with the continuously monitored emptying parameters, in order to obtain a controlled pre-rolling, or soft reduction, of the ingot, thus exploiting the inclusion of the liquid core and the characteristics of the plasticity of the solidified crust that is being formed. This feature of the method not only ensures operational advantages in the structure of the crystallizer and discharge nozzle as shown in the previous document, but also allows a refinement in the solidification structure of the metal and the elimination of the central segregation in the ingot that is going to achieve. In addition, the versatility of the machine increases considerably and the extraction speeds that can be achieved, can be much higher. However, this result produces an optimum length of smooth reduction, measured from the exit of the mold, and this length has to be calculated on each occasion and can sometimes take large values. As mentioned, the point of contact in the modalities of the state of the art has to, instead, stay within the container and guide 103 assemblies, or by much, be immediately below it, strongly limiting then the versatility of the plant and extraction speed. The present applicants have designed and tested this invention to overcome these disadvantages of the more developed state of the art of continuous vertical emptying and to achieve additional advantages. This invention is set forth and characterized in the main claim, while the dependent claims describe variants of the idea of the main mode. The purpose of the invention is to present a vertical continuous casting line for ingots, and in particular for thin and medium sized ingots, in which it is possible to achieve a great versatility of the plant and a high extraction speed, and therefore , a large production of the plant, and obtain at the same time, a good internal and superficial quality of the product. Another purpose is to provide the improved vertical emptying line without altering the conformation and arrangement of most of the elements that constitute the continuous vertical emptying machine, thus adopting the line according to the invention, being also advantageous in terms of investment . This improved vertical emptying line can then be incorporated into any pre-existing plant without major structural changes or difficult adaptations. According to the invention, the container and guide assemblies have the task of possible controlled pre-rolling and consequently, that the smooth reduction of the ingot left by the mold takes, at least, the entire vertical segment of the line emptied In this case, according to the invention, the contact point can be moved longitudinally as desired, along the entire vertical segment of the line and also beyond, depending on the type of cast steel and other processing parameters. . In accordance with the invention, the position of the extraction assembly is lowered in order to cooperate, at least, with the beginning of the curve that the ingot makes to arrive from the vertical emptying plane to the horizontal rolling plane. This assures the empty product a long space and therefore a long time to complete the solidification process before being in cooperation with the gripping rollers of the extraction assembly. By the gentle reduction, which is carried out, at least in the second vertical segment of the drainage line, but conveniently along the entire vertical part, the thickness of the drained product is progressively reduced by conveniently using the presence of the core liquid, which makes possible the use of limited rolling forces that can be supported by the rollers of a small diameter of the container and guide assemblies. According to the invention, the point of contact can be displaced as desired as far as the exit of the last container and guide assembly, so that the product that is put in cooperation with the extraction assembly, placed at least in the beginning of the curvature will have a sufficiently strong and stable internal structure to obviate the effects of thickening and deformation caused by contact with the extraction rollers. Furthermore, according to the invention, the rollers of the last container and guide assembly are located in a position extremely close to the first extraction roller, so that no deformation or tension of the solidified crust is allowed until the moment of the extraction. output of the empty product of the last container and guide assembly. According to a variant, the extraction assembly is replaced by a plurality of container and guide assemblies, arranged along the entire arc of the curve followed by the product substantially up to the vicinity of the stretch assembly placed horizontally in the plane of rolling. This makes possible an additional prolongation of the solidification process resulting in a greater versatility of the plant. In fact, this situation allows the point of contact to be moved to a desired long zone immediately upstream of the horizontal stretch assembly, and that a desired controlled soft reduction in the emptied product is carried out. The appended figures are given as a non-restrictive example and show some preferred embodiments of the invention as indicated below: Figure 1 shows a continuous vertical pour line for ingots of the state of the art, Figure 2 shows a first embodiment of the continuous vertical emptying line for ingots according to the invention; Figure 3 shows a variant of Figure 2. The continuous dump machines 10a and 10b, shown in Figures 2 and 3, have a height extension "I" of a value of about 10800 to 1 1800 mm. , which can be substantially compared to that of the continuous dump machine 100 of the state of the art, and employ a mold 1 1 which can be completely analogous to the mold 101 of Figure 1. According to the invention, an assembly of lower roll 12, which has a very modest height "b" of about 150 to 250 mm, is included downstream of mold 1 1. The lower roller assembly 12 can be replaced by plates, strips, or other similar container elements. A plurality of container and guide assemblies 13, whose rollers 14 limit an ingot 18 laterally during its descent and at the same time exert a controlled pre-rolling action (smooth reduction), at least along the second vertical segment of the shaft. drain line, is immediately included downstream of the lower roller assembly 12. In order to perform this task, the rollers 14 of the assemblies 13 cooperate individually or in groups with drive means 19, governed by a data processing unit 20. (shown for convenience only in Figure 2), which continuously controls the emptying parameters and adjusts the positions and speeds of the rollers 14 relative to the ingot 18.

This data processing unit 20 can also perform other tasks related to the control of the method of continuous emptying, such as, for example, the coordination between the work of the mold 1 1 and the actuation of the rolls 14, the control of the position of the container and guide sets 13 by the type of material emptied, the temperatures continuously monitored, the extraction speed, etc. The container and guide assemblies 13, cooperate with secondary cooling systems, which are not shown here but help the progressive completion of the solidification process. In the example of Figure 2, the container and guide assemblies extend along a height "c" of about 6800 to 7200 mm. , in order to substantially cover the entire vertical segment having a height "f" of about 8000 to 8800 mm; of the emptying line 10a. In fact, the extraction assembly 15 is located at least beyond the area of the beginning of the arc of a circumference followed by the ingot 18, ai moving from the vertical emptying position to the horizontal rolling position. The last container and guide assembly 13a, has its rollers 14 which extend to a position extremely close to the rollers 17 of the extraction assembly 15.

The position of the contact point can thus be extended along all the container and guide assemblies 13, that is, along the entire vertical part of the emptying line. In other words, the position of the contact point can be varied as desired, in relation to the identification of its best value, at least along the entire vertical part of the emptying line and also in an area immediately afterwards. from that vertical part. The liquid core inside the ingot 18, is always controlled because the rollers 14 exert a limited and substantially continuous pressure since the very limited space between the coupling surface of a roller 14 and that of the next roller 14, does not allow the solidified crust it deforms or thickens under the thrust of that liquid core. Lowering the extraction assembly 15 provides the ingot 18 with a wide area for carrying out the progressive solidification process before being put into cooperation with the rollers 17 of the extraction assembly 15. In this case, the extraction rollers 17 have a first emptying position 17a, and a second emptying position 17b for the extraction of the starter bar and / or for sampling. In the final segment of the curvature of the path made by the ingot 18, a stretching assembly 16 is included, which sends the ingot 18 for cutting and to the successive processing stations. In accordance with the variant shown in Figure 3, there is a plurality of container and guide assemblies 13b, which accompany the ingot 18, along the entire arc of the circumference traveled to reach a zontal position. This embodiment allows the position of the contact point to be displaced in the vicinity of the stretching assembly 16. This situation is possible because the container and guide assemblies 13b, which have a structure substantially analogous to that of the container and guide assemblies 13 , they can act on the ingot 18 still containing a liquid core without causing the aforementioned disadvantages. With this modality, the versatility of the plant can be increased considerably and the gentle reduction can be made more effective, since it is dispersed throughout a very extended zone.

Claims (4)

1. CLAIMS 1. Vertical casting line for ingots, comprising at least one mold, a set of lower rollers located at the outlet of the mold, a plurality of container and guide assemblies associated with the vertical segment of the line, a possible extraction assembly, cooperating downstream with the last container and guide assembly and a stretching assembly, associated with the horizontal segment of the line, the emptying line being characterized in that the container and guide assemblies cover at least all the vertical segment of the emptying line, and because at least part of the rollers of the container and guide assemblies cooperate with actuating means governed by a data processing unit, to obtain a controlled pre-rolling (soft reduction), for at least in the second part of the vertical segment of the emptying line.
2. 2. The emptying line of claim 1, wherein the rollers of the container and guide assemblies are suitable for carrying out a controlled pre-rolling (soft reduction) along the entire vertical segment of the emptying line.
3. The emptying line of claim 1 or 2, wherein the last element of the last container and guide assembly has a neighborhood relation close to the first element of the extraction assembly.
4. 4. The emptying line of any preceding claim, wherein the container and guide assemblies extend into the vicinity of the horizontal stretch assembly.