Joint structure for casting nozzle

Abstract: A casting nozzle joint structure capable of easily positioning and jointing a nozzle without any holder for fixing and supporting a continuous casting nozzle therethrough. The joint structure comprises fitting means formed in and on the mating faces of the continuous casting nozzle and the pressure clamper. The fitting means includes a convex portion and a concave portion formed in and on the mating faces of the continuous casting nozzle and the pressure clamper so that they fit one another. The concave or convex portion formed in the mating face of the continuous casting nozzle is fitted on or in the convex or concave portion formed in the mating face of the pressure clamper, and this pressure clamper clamps the fitted engagement. Thus, the nozzles can have their outlet bores positioned, and the submerged entry shroud can have its discharge port oriented.

Description: BACKGROUND OF THE INVENTION Field of the Invention : The present invention relates to a joint structure for jointing between a pressure clamper and a casting nozzle to the lower portion of a further casting nozzle which is attached to a ladle or tundish of a continuous steel casting apparatus. Description of the Prior Art : The continuous steel casting apparatus is equipped with a portion, at which two nozzles, such as a ladle lower nozzle and a ladle shroud, or a tundish lower nozzle and a submerged entry shroud, have to be jointed to each other. This joint will be described in the prior art by using the joint between a submerged entry shroud and a slide gate as an example. As shown in Fig. 12 and Fig. 13, presenting a top plan section taken along line - of Fig. 12, there is currently adopted a structure in which a submerged entry shroud "a" mounted by a hanger-like pressure clamper "f" on a holder "e" through mortar "d" is pressed onto a bottom of a casting nozzle "c" fixed on the bottom of a slide gate "b". However, this joint structure of the prior art is defective in that it is deformed in the holder by heat, which is transferred from the molten steel flowing through the nozzles, and so requires periodic replacements. Another defect is that the mortar used for fixing the nozzles deteriorates the working efficiency so that it takes a long time to set and joint the nozzles. Still another defect is that the submerged entry shroud requires its discharge port to be oriented in a predetermined direction, thus making it difficult to position the nozzles relative to each other. SUMMARY OF THE INVENTION An object of the present invention relates to a casting nozzle joint structure capable of easily positioning and jointing a nozzle without any holder while eliminating the defects of the prior art. According to an aspect of the present invention, there is provided a joint structure comprising a pressure clamper for fixing and supporting a continuous casting nozzle to the lower portion of a further casting nozzle which is attached to a ladle or tundish of a continous steel casting apparatus, wherein the improvement comprises a fitting means formed in and on the mating faces of said continuous casting nozzle and said pressure clamper. The fitting means may include a convex portion and a concave portion formed in and on the mating faces of the continuous casting nozzle and the pressure clamper so that they fit one another. The fitting means can be exemplified by any arbitrary type of toggle, cotter and bayonet mechanisms known in the prior art. According to another aspect of the present invention, the fitting means can be provided in a desired number, as necessary. According to a further aspect of the present invention, the joint structure can comprise a disengagement preventing means for preventing the fitted faces of the continuous casting nozzle and the pressure clamper from coming apart. According to a yet further aspect of the present invention, the joint structure can comprise a reinforcing structure including a reinforcing metal plate sandwiched between the mating faces of the continuous casting nozzle and the pressure clamper for reinforcing the fitted portions by receiving the locally concentrated pressure. The concave or convex portion formed in the mating face of the continuous casting nozzle is fitted on or in the convex or concave portion formed in the mating face of the pressure clamper, and this pressure clamper clamps the fitted engagement. As a result, the nozzles can have their outlet bore positioned and, still the better, the submerged entry shroud can have its discharge port oriented. BRIEF DESCRIPTION OF THE INVENTION Fig. 1 is a vertical section showing a first embodiment of the present invention; Fig. 2 is a top plan section taken along line - of Fig. 1; Fig. 3 is a vertical section showing a second embodiment of the present invention; Fig. 4 is a top plan section taken along line - of Fig. 3; Fig. 5 is a vertical section showing a third embodiment of the present invention; Fig. 6 is a top plan section taken along line - of Fig. 5; Fig. 7 is a vertical section showing a fourth embodiment of the present invention; Fig. 8 is a top plan section taken along line - of Fig. 7; Fig. 9 shows a disengagement prevention mechanism disposed at the side of the pressure clamper; Fig. 10 is a vertical section taken along line - of Fig. 9; Fig. 11 shows a reinforcing structure for a fitting recess of a submerged entry shroud; Fig. 12 shows a joint structure between the submerged entry shroud and the sliding nozzle according to the prior art; and Fig. 13 is a top plan section taken along line - of Fig. 12. DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments to be described are exemplified by applying the fitting means to a joint between the submerged entry shroud and the slide gate, as shown in Fig. 12. Illustrations will be made to emphasize the relation between the submerged entry shroud 1 and the pressure clamper (or hanger) 4. Embodiment 1: Fig. 1 shows a first embodiment, and Fig. 2 is a top plan section taken along line - . As shown in these Figures, the submerged entry shroud 1 has its support face 2 formed with a semicircular recess 3, and the pressure clamper 4 of hanger type, for example, is formed with a ridge 5 which is sized and positioned to correspond to the recess 3 of the casting nozzle. Thus, the ridge 5 is press-fitted in the recess 5 by the pressure clamper 4. Embodiment 2: Fig. 3 shows a second embodiment, and Fig. 4 is a top plan section taken along line - . In this embodiment, the recess 3 formed in the submerged entry shroud 1 is circular so as to extend around the root of the support face 2 of the submerged entry shroud 1, and a ridge 5 is also formed in the hanger type pressure clamper 4 so that it is sized and positioned to correspond to the recess 3. Embodiment 3: Fig. 5 shows a third embodiment, and Fig. 6 is a top plan section taken along line - . In this embodiment, the support face 2 of the submerged entry shroud 1 is formed on the center of its base with straight recesses 3 which are to fit the ridges 5 of the pressure clamper 4. This structure is additionally given a function to prevent the fitting from faltering between the nozzle 1 and the pressure clamper 4, the faltering being caused by the deformation coming from a thermal load carried over a long period. This structure provides the straight fitting means with another advantage in that it can be set relatively simply. Embodiment 4: Fig. 7 shows a fourth embodiment, and Fig. 8 is a top plan section taken along line - . In this embodiment, another straight recess 31 is formed at a right angle with respect to the straight recesses 3 formed on the center of the base of the support face 2 in the embodiment 3 shown in Figs. 5 and 6. The pressure clamper 4 is also formed with a corresponding ridge 51 at a right angle with respect to the ridges 5, and the pressure clamper 4 is reinforced by a reinforcing bottom plate 41 extending therefrom. As a result, the fitting joint between the submerged entry shroud 1 and the pressure clamper 4 is strengthened when pressed by the clamper 4, so that the connection to the tundish nozzle, as shown in Fig. 12, can be better ensured. Embodiment 5: In Fig. 9 and Fig. 10, presenting the longitudinal section taken along line - , there is shown the fifth embodiment, in which the support face 2 of the submerged entry shroud 1 is formed therein with a recess at a right angle with respect to the recess or recesses 3 of the foregoing individual embodiments, whereas the pressure clamper 4 is formed with a ridge at a right angle with respect to the ridge or ridges 5 to be fitted in the recess or recesses 3, thus constituting a disengagement prevention mechanism 6. Thanks to this mechanism 6, the ridge 5 of the pressure clamper 4 is prevented from moving in the direction indicated by the arrow out of engagement with the recess 3 formed in the support face 2 of the submerged entry shroud 1. Embodiment 6: Fig. 11 shows a reinforcing structure for receiving the pressure to be concentrated in the recess 3, which is formed in the support face 2 of the submerged entry shroud shown in the foregoing individual embodiments, when the projection of the pressure clamper is fitted in the recess 3, thereby preventing the recess 3 from being broken. As shown in the same Figure, the reinforcing structure includes a reinforcing metal plate 8 which is formed with a recess 7 corresponding to the recess 3 formed in the support face 2 of the submerged entry shroud 1. This metal plate is arranged on the support face 2 of the submerged entry shroud 1 for reinforcing the fitted portions by receiving the locally concentrated pressure. In a modification, this metal plate 8 may be shaped into a casing shape covering the supporting face 2 of the submerged entry shroud 1. The joint structures thus embodied above were adopted for connecting the ladle lower nozzle of 300 tons, and the submerged entry shroud, and were subjected to casting operations of eight charges for 400 minutes. It was confirmed that the joint experienced no such deterioration as to cause either the invasion of air or leakage of molten steel. According to the casting nozzle joint structure of the present invention, neither mortar nor any holder need be used for ensuring the reliable positioning and connection when a nozzle is to be attached to the ladle or tundish of an ordinary casting nozzle or a continuous casting nozzle such as the ladle shroud or the submerged entry shroud.

Claims: A casting nozzle joint structure comprising a pressure clamper (4) for fixing and supporting a continuous casting nozzle (1) to the lower portion of a further casting nozzle which is attached to a ladle or tundish of a continous steel casting apparatus, wherein the improvement comprises a fitting means (3, 5) formed in and on the mating faces of said continuous casting nozzle (1) and said pressure clamper (4). A casting nozzle joint structure according to Claim 1, wherein said fitting means includes a convex portion and a concave portion formed in and on the mating faces of said continuous casting nozzle and said pressure clamper such that they fit into one another. A casting nozzle joint structure according to Claim 2, wherein said concave portion has a semicircular recess, and wherein said convex portion has a ridge sized and positioned to correspond to said recess. A casting nozzle joint structure according to Claim 2, wherein said concave portion has a circular recess, and wherein said convex portion has a ridge sized and positioned to correspond to said recess. A casting nozzle joint structure according to Claim 2, wherein said concave portion has straight recesses, and wherein said convex portion has straight ridges sized and positioned to correspond to said straight recesses. A casting nozzle joint structure according to Claim 2, wherein said concave portion further has a straight recess at a right angle with respect to said straight recesses, and wherein said convex portion further has a straight ridge sized and positioned to correspond to said straight recess. A casting nozzle joint structure according to Claim 1, wherein said fitting means are provided in a desired number. A casting nozzle joint structure according to Claim 1, further comprising a disengagement prevention means for preventing the fitted faces of the continuous casting nozzle and the pressure clamper from becoming disengaged. A casting nozzle joint structure according to Claim 1, further comprising a reinforcing structure including a reinforcing metal plate sandwiched between the mating faces of said continuous casting nozzle and said pressure clamper for reinforcing the fitted portions by receiving the locally concentrated pressure.

Inventors: ARIMITSU EIZABURO, KAWABE HIDEAKI, KIMURA HARUYOSHI, TSUYUGUCHI KOJI, ARIMITSU, EIZABURO, KAWABE, HIDEAKI, KIMURA, HARUYOSHI, TSUYUGUCHI, KOJI, Arimitsu, Eizaburo, c/o AMR Refractarios. SA, Kawabe, Hideaki, c/o Krosaki Corporation, Kimura, Haruyoshi, c/o Krosaki Corporation, Tsuyuguchi, Koji, c/o Krosaki Corporation Europe
Applicants: KROSAKI CORP, KROSAKI CORPORATION
Application year: 1993
Main classification: B22D41
IPC codes: B22D41, B22D11