JP2010207848A - Long nozzle and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long nozzle capable of preventing occurrence of cracks of the nozzle body caused by thermal expansion of a refractory ring mounted on the upper part of a bore face, and to provide a method of manufacturing the same. <P>SOLUTION: The long nozzle 1 is the one which has an outer periphery covered with a shell 12 and which is designed to pour molten metal of a ladle into a tundish. On the upper part 3 of the nozzle bore 2, a fitting part 10 is formed for fitting the refractory ring 4, wherein the refractory ring 4 has a fibrous heat insulation material 5 stretched over the outer periphery and is fitted to the fitting part 10 via mortar 11 arranged on the upper part 3 of the nozzle bore 2. As a result, the thermal expansion margin in the radial direction of the highly corrosion resistant refractory ring 4 can be absorbed by the fibrous heat insulation material 5 which is stretched over the outer periphery of the refractory ring 4. Also, the thermal expansion of the refractory ring 4 is suppressed by fixation with the mortar 11, which prevents the occurrence of cracks of the nozzle body 6. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a long nozzle for pouring molten metal in a ladle into a tundish and a method for manufacturing the same.

  In continuous casting of steel or the like, the molten metal flowing out from the lower nozzle to the long nozzle becomes a turbulent and non-uniform flow due to the opening degree of the sliding nozzle disposed at the bottom of the ladle. In particular, since this uneven flow occurs at the beginning of molten steel injection, the upper part of the inner surface of the long nozzle is subjected to uneven contact with the molten steel and is partially eroded (perforated), resulting in poor sealing and refractory. It is a cause of carbon pickup coming from melting.

  In order to solve this problem, a refractory ring having high corrosion resistance (cap 8 in FIG. 1 in Japanese Patent Laid-Open No. 2008-194745) is attached to the upper part of the inner hole surface of the long nozzle through a mortar. Yes.

  However, this refractory ring with high corrosion resistance generally has a thermal expansion coefficient more than twice that of the material of the nozzle body present on the outer periphery, so when the refractory ring is attached to the nozzle body using mortar, The mortar cost alone cannot absorb the thermal expansion allowance of the refractory ring, and may cause cracks in the nozzle body existing on the outer periphery. In addition, the upper part of the nozzle body is covered with an iron skin for reinforcement, but this iron skin heats up the nozzle body and promotes the thermal expansion of the refractory ring and may induce cracks in the nozzle body. there were.

JP 2008-194745 A

  The present invention has been made to solve the above-described problems. That is, the object of the present invention is to prevent the occurrence of cracks in the nozzle body due to thermal expansion of a refractory ring attached to the upper portion of the inner hole surface. It is an object of the present invention to provide a long nozzle and a method for manufacturing the same.

  What solves the above-mentioned problem is a long nozzle whose outer periphery is covered with an iron skin and injects a molten metal in a ladle into a tundish, and a fitting for fitting a refractory ring in the upper part of the nozzle bore. The refractory ring is fitted with the fitting part through a mortar disposed at the upper part of the nozzle inner hole, and the refractory ring is stretched with a fiber heat insulating material on the outer periphery. It is a long nozzle.

  The outer surface of the refractory ring is formed into a tapered surface whose diameter decreases downward, and the gap between the inner surface of the fitting portion and the outer surface of the refractory ring is an upper portion of the nozzle inner hole. It is preferable that a mortar for joining the refractory ring is configured to be able to enter.

  Moreover, what solves the said subject is the manufacturing method of the long nozzle which the outer periphery is coat | covered with the iron shell, and injects the molten metal in a ladle into a tundish, Comprising: The refractory material fitted by the upper part of a nozzle inner hole A long nozzle manufacturing method comprising a step of fitting a refractory ring to an upper portion of the nozzle inner hole through a mortar after a fiber heat insulating material is stretched around the outer periphery of the ring.

According to the long nozzle described in claim 1, it is possible to prevent the nozzle body from cracking due to the thermal expansion of the refractory ring mounted on the upper portion of the inner hole surface.
According to the long nozzle described in claim 2, in addition to the effect of claim 1, a gap is formed between the outer surface of the fiber heat insulating material and the fitting portion, and the mortar penetrates into the gap. The sealing performance can be further increased.
According to the method for manufacturing a long nozzle according to claim 3, it is possible to prevent cracking of the nozzle body due to thermal expansion of the refractory ring mounted on the upper portion of the inner hole surface, and to prevent the refractory ring and the nozzle body. Therefore, it is possible to manufacture a long nozzle that can stably cast high-quality steel for a long time.

It is a longitudinal cross-sectional view of the upper part vicinity of the long nozzle of one Example of this invention. It is explanatory drawing for demonstrating the manufacturing method of the long nozzle of this invention.

  In the present invention, the thermal expansion allowance in the radial direction of the refractory ring having high corrosion resistance can be absorbed by the fiber heat insulating material stretched on the outer periphery of the refractory ring, and the refractory ring is fixed by the mortar 11. A long nozzle that can suppress the thermal expansion of the nozzle body 6 and prevent the nozzle body 6 from cracking has been realized.

A long nozzle according to the present invention will be described with reference to an embodiment shown in FIG.
The long nozzle 1 is a long nozzle whose outer periphery is covered with a steel shell 12 and injects the molten metal in the ladle into the tundish, and is fitted in the upper part 3 of the nozzle inner hole 2 for fitting the refractory ring 4. The refractory ring 4 is formed with a fiber heat insulating material 5 stretched on the outer periphery, and is fitted into the fitting portion 10 via a mortar 11 disposed in the upper portion 3 of the nozzle inner hole 2. ing. Hereinafter, each configuration will be described in detail.

  The long nozzle 1 is used in such a manner that the upper part is hermetically connected to the lower nozzle provided at the molten steel discharge port of the ladle and the lower part (not shown) is inserted into the tundish. A nozzle inner hole 2 passes through the nozzle body 6 in the axial direction, and an upper end opening portion 7 made of an oxidation-resistant fire-resistant material is integrally formed at the upper portion of the nozzle body 6. The upper end opening 8 is formed larger than the diameter of the nozzle inner hole 2, and the nozzle inner hole 2 is formed with an inner hole body 9 in which a refractory layer is lined inside in contact with the molten metal flowing down.

  A fitting portion 10 is formed in the upper end opening portion 7 continuously to the upper end opening 8, and a removable refractory ring (planar cylindrical shape) 4 is fitted in the fitting portion 10. ing. The lower surface of the refractory ring 4 is joined and abutted to the upper end surface of the inner hole body 9 through the mortar 11. Expansion of the refractory ring 4 is suppressed by fixing the lower surface to the mortar 11. In the drawing, the mortar 11 is drawn thicker than the actual thickness in order to clarify the sealing portion by the mortar 11. Further, the outer periphery of the long nozzle 1 is covered with an iron skin 12.

  The refractory ring 4 is formed of the same material as the inner hole body 9, and a fiber heat insulating material 5 is stretched on the outer periphery (outer peripheral side surface or outer side surface) of the refractory ring 4. The outer surface of the refractory ring 4 is a tapered surface whose diameter decreases downward, and the refractory ring 4 is fitted in the fitting portion 10. By making the outer surface of the refractory ring 4 a tapered surface whose diameter decreases downward, the refractory ring 4 can be easily fitted into the fitting portion 10 and can be tightly fitted. Furthermore, since a gap is formed between the outer surface of the fibrous heat insulating material 5 and the fitting portion 10, the mortar 11 can enter the gap to further improve the sealing performance.

  As described above, the long nozzle 1 of the present invention has the thermal expansion allowance in the radial direction of the refractory ring 4 since the fibrous heat insulating material 5 is wound around the outer periphery of the refractory ring 4 and stretched. It can be absorbed by the fiber heat insulating material 5 stretched around the outer periphery of the ring. More specifically, when the refractory ring 4 is thermally expanded in the radial direction, the fibrous heat insulating material 5 is contracted in the thickness direction, so that the nozzle body 6 (the upper end opening portion 7 in this embodiment) is pressed from the inside. No cracking of the nozzle body due to thermal expansion of the refractory ring can be prevented.

  As the fiber heat insulating material, any fiber material having necessary heat resistance may be used. For example, an alumina / silica ceramic sheet can be preferably used.

  The shrinkage rate of the fibrous heat insulating material is preferably about 50 to 90% when a refractory ring is attached with a mortar cost of 1 mm. If it is less than 50%, the expansion allowance in the radial direction of the refractory ring may not be absorbed, and if it exceeds 90%, it will be difficult to handle the fiber heat insulating material. Moreover, as a thickness of a fiber heat insulating material, when a refractory ring is mounted | worn with the mortar cost 1mm, about 0.5-2 mm is preferable. That is, the ratio of the mortar allowance to the thickness of the fiber heat insulating material (mortar allowance / fiber heat insulating material thickness) is preferably about 0.5 to 2.

Next, the manufacturing method of the long nozzle of the present invention will be described with reference to FIG.
In the manufacturing method of the long nozzle 1 of the present invention, the fiber heat insulating material 5 is stretched around the outer periphery of the refractory ring 4 fitted to the upper portion 3 of the nozzle inner hole 2, and then the refractory ring 4 is attached to the nozzle inner hole 2. The upper part 3 of the refractory ring 4 has a process of fitting through the mortar 11 and is characterized by the process of fitting the refractory ring 4. In addition, about each structure of the long nozzle 1, it is as above-mentioned, and description is abbreviate | omitted.

  Specifically, in the method for manufacturing a long nozzle of the present invention, when the refractory ring 4 shown in FIG. 2A is fitted into the upper portion 3 of the nozzle inner hole 2, first, FIG. As shown in Fig. 5, a fiber heat insulating material 5 is stretched around the outer periphery of the refractory ring 4. Then, as shown in FIG. 2C, after applying the mortar 11 to the upper end surface of the nozzle inner hole 2, the fiber heat insulating material 5 was stretched around the outer periphery shown in FIG. The refractory ring 4 is fitted into the upper portion 3 of the nozzle inner hole 2 (state shown in FIG. 1). Since the outer surface of the refractory ring 4 is formed into a tapered surface whose diameter decreases downward, a gap is formed between the outer surface of the fiber heat insulating material 5 and the fitting portion 10. When the mortar 11 penetrates into the sealant, the sealing performance becomes higher. In this embodiment, the mortar 11 is applied to the upper end surface of the nozzle inner hole 2, but the mortar 11 applied to the lower end surface of the refractory ring 4 is also included in the scope of the present invention.

  Thus, the long nozzle manufactured by the manufacturing method of the present invention can absorb the thermal expansion allowance in the radial direction of the refractory ring with the fiber heat insulating material stretched around the outer periphery of the refractory ring. At the same time, since the thermal expansion of the refractory ring 4 is suppressed by fixing with the mortar 11, it is possible to prevent the nozzle body from cracking due to the thermal expansion of the refractory ring. Moreover, since the sealing performance between the lower end surface of the refractory ring and the upper end surface of the nozzle inner hole is maintained by the mortar, high quality steel can be stably cast for a long time.

DESCRIPTION OF SYMBOLS 1 Long nozzle 2 Nozzle inner hole 3 Upper part of nozzle inner hole 4 Refractory ring 5 Fiber heat insulating material 6 Nozzle main body 7 Upper end opening part 8 Upper end opening part 9 Inner hole body 10 Insertion part 11 Mortar 12 Iron skin

Claims (3)

  A long nozzle whose outer periphery is covered with an iron skin and injects a molten metal in a ladle into a tundish, and a fitting portion for fitting a refractory ring is formed in the upper portion of the nozzle inner hole. A long nozzle characterized in that a fiber ring is stretched around the outer periphery of the object ring and is fitted into the fitting portion via a mortar disposed above the nozzle inner hole.   The outer surface of the refractory ring is formed into a tapered surface whose diameter decreases downward, and the gap between the inner surface of the fitting portion and the outer surface of the refractory ring is an upper portion of the nozzle inner hole. The long nozzle according to claim 1, wherein a mortar for joining the refractory ring is configured to be able to enter.   This is a long nozzle manufacturing method in which the outer periphery is covered with a steel shell and the molten metal in the ladle is poured into the tundish, and a fiber insulation is applied to the outer periphery of the refractory ring fitted in the upper part of the nozzle bore. A method of manufacturing a long nozzle, comprising: a step of fitting the refractory ring to an upper portion of the nozzle inner hole through a mortar after installation.

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