CN1221346C - Method for sealing ingot-mould/dummy-bar assembly in continuous-casting plant, and corresponding seal element - Google Patents

Abstract

In a continuous-casting plant, a method of utilization sealing gasket between the dummy bar and the ingot mould envisages a seal element to be installed directly within the ingot mould outside of the continuous-casting plant. Said seal element(1)may be either in the form of a slightly deformable single sheet, or in the form of a rigid plate bearing along the entire edge a plurality of deformable detached parts(10)making up a continuous sealing gasket.

Description

Sealing method for ingot mold/dummy rod assembly in continuous casting equipment and corresponding seals

technical field

The invention relates to a sealing method for an ingot mold/dummy bar assembly in continuous casting equipment, a sealing gasket for implementing the method, and the use of the sealing gasket in continuous casting. More specifically, the present invention relates to a method of inserting a shaped gasket into a mold in complete safety, ie not on-line.

Background technique

In continuous casting plants, liquid metal is poured into open-bottom cooled molds or ingot molds located above the production line to be extracted and further cooled. When in contact with the cold inner walls of the ingot mould, the poured metal solidifies to form an encrustation, which generally still contains liquid metal, which is withdrawn in a continuous manner from the bottom of the ingot mould. The liquid metal contained within the shell solidifies completely along the casting line, and after complete solidification the blanks thus produced are generally straightened and then cut into sections of predetermined length.

At the beginning of the casting operation, when the ingot mold is still completely empty, means must be employed to prevent molten metal from flowing out of the ingot mold until a crust of sufficient thickness and strength has formed before pulling it from the ingot mold.

For this purpose, a body called a dummy bar is used, which has a section slightly smaller than that of the ingot mould, in order to temporarily close the ingot mould. The dummy bar is on one side in contact with the extraction assembly below, while on the other side it is equipped with means of hooking onto the blank formed by the solidification of the liquid metal in the ingot mould. Considering the low viscosity of liquid metal (for example, the fluid properties of liquid steel can be compared with water), it is obvious that the space existing between the inner wall of the ingot mold and the dummy rod must be completely sealed in order to prevent the leakage of liquid metal and subsequent The resulting blockage of the casting machine, damage to the casting machine, or worse, the possibility of endangering the safety of workers. Sealing is mainly done in two ways: either by placing the sealing material in the mold after the dummy rod has been inserted into the working position, or by using the sealing material as a gasket before the dummy rod is inserted into the mold (gasket) placed on the head of the dummy rod. However, these methods suffer from serious drawbacks. In fact, in order to put the sealing material into the ingot mold, or require the worker to go to the mouth of the ingot mold, which is under the tundish and in any case is used to support or move the tundish. Below the equipment, or, for example, as suggested by published Japanese patent application JP 7-314099, an automated machine is used which sprays the sealing material on the inside of the ingot mould. However, in the former case, the working conditions are inconvenient and dangerous, while in the latter case, it is impossible to be sure that the sprayed sealing material layer is completely free from damage without dangerous cracks or gaps. In any event, the use of additional machinery adds to the complexity and cost of the process. If not, a gasket is used to rest directly on the head of the dummy bar, for example, as in published Japanese patent application JP8174160, or on an interposed plate, as in European patent application As in Book No. 231520, it is necessary to prevent the gasket from being damaged by impact or fracture when the dummy rod reaches the ingot mould. Therefore, the gasket must be installed directly in front of the ingot mould, and, in order to do this, the worker has to work in the cooling chamber below the ingot mould, for fixing the gasket to the head of the dummy bar, That is to work under even more inconvenient and more dangerous working conditions than at the mouth of the ingot die.

Contents of the invention

The present invention overcomes these disadvantages by providing a seal.

The method of sealing the mold/dummy bar assembly in a continuous casting plant according to the present invention is mainly based on the fact that, using preformed seals, the dummy bar is removed from the casting line used before it is inserted into the ingot mould. , preferably outside the casting apparatus, the above-mentioned preformed seal is installed inside the ingot mould. This latter solution is preferred due to its main advantages in terms of the number of implementations and because it provides conditions of absolute safety when implemented. However, there may be situations, such as spare equipment with ingot molds installed next to the casting line being used, where it may be indicated that the gasket must be installed inside the casting equipment, despite being used outside the casting line.

The above-mentioned seal is preferably equipped along its entire edge with a circumferentially protruding raised portion which is approximately at right angles to the plane of the seal and has a tapering section towards the free end so that when the dummy rod is inserted The head of the dummy bar fits easily when inside the ingot mold and is gradually compressed between the dummy bar and the ingot mold to ensure a complete seal.

Furthermore, the seal can consist of a single, sheet-like body of plastic material, or of several parts which are consolidated by associated rigid plates, for example of metal.

The seal, manufactured as a one-piece body, may have a central through hole through which the fastening element between the dummy rod and the casting blank is attached to the dummy rod. The aforementioned securing elements may be detached from the dummy bar and fixed to the dummy bar with quick clamping and quick release devices as it reaches the ingot mould, or else to the aforementioned rigid plate, The aforementioned rigid plates are in turn connected to the dummy bars with quick clamp and quick release devices.

In the case of seals with several parts consolidated by rigid plates, these parts are, for example, in the form of elongated bodies with a U-shaped cross-section, the longitudinal cavities of which fit into the above-mentioned rigid consolidated plates. edge.

In any case, the seal, whether taken as a whole or as a set of parts assembled on a rigid plate, has, in plan view, the same shape as the horizontal section of the ingot mold with which it is applied, and the linear dimensions of each side are smaller than The dimension of the corresponding side of the ingot mold is slightly larger, for example between 0.1 and 4%, or in the case of an ingot mold with a circular cross-section, slightly larger than the diameter of the ingot mold, so that, due to the difference in size, it is caused by the deformation of the seal The resulting friction will keep it in place within the ingot mould.

Preferably, the seal has a central through hole, which can also be equipped with several cutouts starting from the central hole, to facilitate the passage of elements consolidated with the cast blank.

In practice, for one of each section of the ingot mold, several types of seals are prepared. When using a particular ingot mould, a suitable seal is selected and installed in the ingot mould, prior to insertion of the dummy bar, where it remains closed because, as previously stated, it has dimensions larger than the ingot A section with a slightly larger internal dimension of the mold. In the preferred case, from which it is operated outside the casting plant, the ingot mold equipped with the sealing gasket can then be transported in due course to the continuous casting machine and fixed on the continuous casting machine.

In any case, when the ingot mold equipped with the gasket is in the casting line, the dummy rod equipped with elements for hooking onto the cast blank is brought upwards to the ingot mold and pushed into it. The engagement between the dummy rod, the inner wall of the mold and the seal helps to squeeze the periphery of the seal against the mold, especially if the seal has raised portions projecting at right angles, thus providing a complete seal .

The element used to fix the dummy bar to the cast body can be of any suitable type, for example a so-called starting hook, or a starting cage, or a screw, can be integral with the dummy bar, or can be obtained from It can be removed from the dummy bar, or it can be integrated with the rigid plate, which can also be connected with the dummy bar in a detachable manner. The above-mentioned securing element or the above-mentioned rigid plate can be connected to the dummy bar by means of quick clamping and quick release elements, such as expansion rings, spring-action hooks or the like.

In order to hasten the formation of the first layer of solidified metal in the ingot mould, and thus to prevent the seals from burning and thus allowing the liquid metal to leak out of the ingot mould, it is possible, in a manner known per se, to equip the inside of the ingot mould, with a sealing gasket Above the spindle, a cooling material, such as a small amount of metal scrap, is added.

Description of drawings

The invention will now be more precisely described by means of certain preferred embodiments with reference to the accompanying drawings, which are purely non-limiting examples, in which:

Fig. 1 is a schematic diagram of a seal according to the present invention;

Figure 2 is a vertical sectional view of an ingot mold equipped with a seal, together with the head of the dummy rod ready to be pushed into the ingot mould;

Figure 3 is the same view as Figure 2, but with the dummy bar inserted into the ingot mould;

Figure 4 is a schematic diagram of a seal formed by several parts combined into a rigid plate;

Figure 5 shows a section of one of the above-mentioned parts forming the seal;

Figure 6 is a vertical cross-sectional view of another embodiment of an ingot mold equipped with a seal according to the present invention, together with the dummy rod head ready to be pushed into the ingot mould;

Figure 7 is the same view as Figure 6, but with the dummy bar inserted into the ingot mould;

Figure 8 is a vertical cross-sectional view of another embodiment of an ingot mold equipped with a seal according to the invention, together with the dummy rod head ready to be pushed into the ingot mould;

Figure 9 is a vertical cross-sectional view of another embodiment of an ingot mold equipped with a seal according to the present invention, together with a dummy rod head inserted into the ingot mold;

Detailed ways

In FIG. 1 , a schematic plan view of a seal 1 is shown, which is provided with a protruding bulge 2 (shown in hatching) on its edge, provided with a central hole 3 and provided with cutouts 4 .

As shown in Figure 2, in each particular ingot mold 5, while it is still outside the casting machine, a suitable seal 1 is fitted. In the figure, the ingot mold is shown to coincide with the head of a dummy bar 7 which is also equipped with means 6 for consolidation with the cast blank. These securing devices 6 may be integral with the dummy bar, or else be detachable, in the case of detachable, quick-clamping and quick-disengaging means 11 of the dummy bar (which are themselves already Known), such as hooks of different shapes or the same shape. Further embodiments of such fastening means 6 and quick clamping means 11, and their combinations, are shown in FIGS. 6-9.

At the beginning of the ingot casting operation, the head of the dummy bar 7 is inserted into the ingot mold 5, as shown in Figure 3, thus squeezing the edge 2 of the seal 1 between the dummy bar and the inner wall of the ingot mould. In the position shown, the securing elements 6 force the cutouts 4 of FIG. 1 to open so as to pass through the holes 3 into the ingot mould, where they hook the metal that is subsequently poured into the ingot mould. The seal 1 is advantageously manufactured from a semi-rigid and deformable material such as plastics, thermoplastic resins and other materials having similar strength and ductility characteristics.

In the latter case, the seal 1 can also be reinforced with reinforcing steel plates 12 if it is necessary to achieve a better retention of the seal 1 inside the ingot mould.

As previously mentioned, the seal 1 may have the shape of a flat sheet made of a relatively rigid deformable material, preferably provided on each edge with a continuous raised portion 2 having a generally wedge-shaped section, while protruding approximately at right angles from the plane of the above-mentioned sheet. Alternatively, as shown in Figure 4, a rigid plate 8 can be used, for example a plate 8 made of metal, which in plan view has the same shape as the internal section of the ingot mold, but with smaller dimensions , this plate is equipped with means 6 for consolidation with the cast blank and means (not shown) for hooking on the dummy bar.

On each edge of the above-mentioned rigid plate 8 is a slot-mounted peripheral seal 10 made of plastic material and forming a continuous projection protruding to the rigid outside the edge of the plate itself, so that the plate plus the seal as a whole assumes its dimensions slightly larger than the internal dimensions of the ingot mould, which is in a sense identical to the object described above in relation to the seal 1 in the form of a thin plate . This unit is mounted inside the mold before the dummy bar is inserted, as already described for the seal 1 . Figure 5 shows two possible cross-sections of the above-mentioned seal 10, which is generally U-shaped and provided with a continuous raised portion 2 having a generally wedge-shaped cross-section.

In the embodiment shown in Figure 8, a peripheral seal 10 may also be utilized.

Figure 9 shows another variant of the section of the seal, in this case the section has the shape of a frame which fits only around the periphery of the dummy bar head and leaves the central hole open in order to provide a The object 13 is combined with a corresponding hook 11, and the hook 11 is integrally fixed to the rigid plate 8.

Claims (9)

1. The seal (1) is used to ensure the seal between the dummy rod (7) and the ingot mold (5) in the continuous casting equipment, and in plan view, has a planar shape, which is inserted into the seal Consistent with the shape of the ingot mold (5), the above-mentioned seal (1) has an integral part (2) along its periphery, and this integral part (2) protrudes substantially at right angles to the above-mentioned planar body, and the above-mentioned protruding The part (2) has a substantially triangular cross-section that tapers approximately in the direction of the dummy bar (7), and is characterized in that the central part of the seal (1) consists of a relatively thin planar body that There is a relatively small central hole for the hooking device (6) protruding from the above-mentioned dummy bar (7) to pass through, which can fix the dummy bar to the continuous casting blank; each side of the seal (1) The linear dimensions are slightly larger than those of the corresponding inner side of the ingot mould, so that when the dummy bar (7) is outside the casting equipment, it is suitable for installation in the ingot mold (5) and is held by friction with the latter. in place. 2. A seal according to claim 1, comprising a rigid plate (1) with fastening means (11) together with the dummy bar (7). 3. A seal according to claim 1, comprising a flexible plate (1, 14) having fastening means (11) together with the dummy bar (7). 4. A seal as claimed in claim 2 or 3, comprising a plurality of separate segments mounted along the edge of said plate. 5. A seal according to claim 2 or 3, wherein said fixing means (11) is releasably fixed to said dummy bar (7). 6. A seal according to claim 3, wherein said flexible plate (14) has a reinforced rigid plate (12). 7. The seal (1) is used to ensure the seal between the dummy bar (7) and the ingot mold (5) in the continuous casting equipment, and in plan view, has a plane shape, which is inserted into the seal Consistent with the shape of the ingot mold (5), the sealing member (1) has a peripheral sealing portion (2), which protrudes substantially at right angles to the above-mentioned planar body, and has a ) direction tapered substantially triangular section, characterized in that the central part of the seal (1) consists of a relatively thin planar object with a relatively small hole (3), The hooking device (6) for protruding from the above-mentioned dummy bar (7) is passed to be able to fix the dummy bar (7) to the continuous casting blank; the above-mentioned peripheral part is installed along the edge of the above-mentioned planar body, And the linear dimensions of each side are slightly larger than those of the corresponding inner side of the ingot mould, so that when the dummy rod (7) is outside the casting equipment, it is suitable for being installed in the ingot mold (5), and through the connection with the latter Friction stays in place. 8. A seal according to claim 7, wherein said peripheral sealing portion (2) is formed of several separate segments (10). 9. Use of the seal (1) according to any one of claims 1-8 in the continuous casting process, the seal (1) is installed before the dummy bar (7) is inserted into the ingot mold (5) In this ingot mold (5).

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