Stopper structure, and its manufacturing method

Abstract

The present invention provides a stopper structure capable of preventing loosening of a shaft rod during use, and gas leakage which is likely to occur when the stopper structure is designed to allow gas to pass therethrough. The shaft rod 1 is adapted to be mounted in a mounting hole 2a of a refractory stopper 2, and formed to have an outer peripheral surface including a first tapered sub-surface 4a which increases in diameter toward an axially lower edge of the shaft rod. The mounting hole 2a of the refractory stopper 2 is formed to have an inner surface including a second tapered sub-surface 4b adapted to come into surface contact with the first tapered sub-surface 4a. The shaft rod 1 is adapted to be fastened to the refractory stopper so as to allow the first tapered sub-surface 4a to be brought into close surface contact with the second tapered sub-surface 4b. The distal end of the shaft rod 1 is formed in a configuration satisfying the following relation: tan theta <= D / 2A, wherein: A is a length of the shaft rod 1 between a position of the shaft rod 1 corresponding to an upper edge surface 2S of the refractory stopper, and a start position of the first tapered sub-surface 4a; D is an outer diameter of the first tapered sub-surface 4a at the start position; and theta is a taper angle of the first tapered sub-surface 4a.

Description

technical field [0001] The present invention relates to a stopper structure used to start or stop the discharge of molten metal from a container through a nozzle, or to control the flow rate (hereinafter simply referred to as "discharge control"). A stopper structure in which a shaft for connecting it to a driving device is mounted on a stopper refractory and a method for manufacturing the same. Background technique [0002] As a discharge control method when molten metal is discharged from the container through the nozzle, there is an operation method of opening and closing the space of the fitting portion with the upper end of the nozzle using a stopper structure provided inside the container. [0003] The stopper structure is generally formed of an integral stopper refractory that is impregnated with molten metal, and a metal shaft is mounted on the top of the stopper refractory that is not immersed in molten metal, and the shaft is connected to the drive unit used. In ...

AI Technical Summary

Problems solved by technology

However, even if such a small-expansion shaft joint part is inserted in advance, when a metal mandrel is joined there, there is a possibility that the shaft joint part may be crushed due to its thermal expansion, and the The length in the vertical direction of the shaft is elongated to cause looseness between the shaft rod and the stopper refractory, making the fixing of the shaft relative to the stopper refractory unstable, and the gas tightness between them cannot be ensured. As a result, the problem of gas leakage cannot be improved

[0015] When looseness occurs between the shaft rod and the stopper refractory due to the elongation of the vertical length of the shaft rod, it is necessary to manually perform so-called tightening, and tighten the bolts continuously during the operation to eliminate the looseness. Since it is done manually and continuously, it is difficult to completely eliminate the gap or looseness, which is also an operational problem

[0016] In this way, it is still impossible to provide a stopper structure that has a structure that does not loosen and does not leak gas during use, and does not need to be tightened.

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