JPH0437445A - Nozzle for continuous casting - Google Patents

Abstract

PURPOSE:To enable improvement of performance as the whole nozzle by dividing the nozzle into a lower part straight stream part and an upper part fitting and distributing part made of formed refractory, joining these with monolithic refractory and assembling. CONSTITUTION:By using the nozzle 1 for continuous casting, a flat slab is manufactured. The nozzle 1 is divided into the lower part straight stream part 2 and the upper part fitting and distributing part and these are joined with the monolithic refractory 6 and assembled. Then, the lower part straight stream part 2 is manufactured with forming refractory and made to flat cylindrical cross section and screw part 3 is arranged at the one end part and single or plural pieces thereof are set. The upper part fitting and distributing part 4 is manufactured with forming refractory and at the center part thereof, the molten metal pouring hole 5 is arranged and this refractory is faced to the screw part 3 side in the lower part straight part 2. The screw part 3 is covered with the monolithic refractory 6 and the outer peripheral face thereof is closely held with iron shell 8. By this method, this nozzle remarkably contributes to the reduction of production cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pouring nozzle used in a continuous casting machine that produces slabs with a flat cross section.

[Prior Art] For example, a twin-belt continuous casting machine that manufactures slabs with a flat cross section used for thin plates, etc., has two opposing rotating belts each having a predetermined plate width, as shown in the side sectional view of Figure 5. 20a
, 20b is injected with molten metal from a nozzle 21 into a mold 2°, and the molten metal is pulled out from the T direction to continuously produce a flat cast slab 22.

The slab 22 manufactured here has a wide and flat cross-sectional shape, so the molten metal injected is uniformly supplied in the width direction within the mold 2° to ensure uniform quality. Therefore, the lower DC sleeve 2 of the nozzle 21
1a has a rectangular or flat cross-sectional shape as shown in the perspective view of FIG. In the figure, 21b is an upper fitting/distribution mantle, and 23 is a molten metal distribution space.

For example, JP-A-50-61332, JP-A-60203
In the casting method using a belt-type continuous casting machine disclosed in Publication No. 345, etc., the nozzle length is 1200 mm and the width is 450 mm.
A nozzle with a shape of mm + 30 mm thickness is shown.

In this way, the thickness of the nozzle 21 is also limited by the width of the mold 20, and the thickness of the lower DC sleeve 21a is also several 1 m to 1 m.
Since it is limited to a thin thickness of 10-odd ml, it is extremely unstable from a structural and strength standpoint, and thermal shock resistance is also required, so a reinforcing rib is added to the core of the lower DC sheath 21a. The material used is fused silica or an alumina-graphite refractory used in molten steel injection nozzles for boat fishing.
The upper fitting distribution mantle 21b is integrally manufactured by firing.

[Problems to be Solved by the Invention] However, as equipment becomes larger, the nozzle length and nozzle width become larger than the nozzle thickness, and the structure becomes complex, so it is necessary to use high-temperature fired refractories or other materials for such nozzles. When fabricating an integrated product using high-strength materials such as fine ceramics, it is extremely difficult to manufacture as it may warp, distort, or crack due to thermal stress, and even if it is possible to fabricate it, the thermal shock resistance is poor. There is an extremely high possibility that thermal spalling will occur in the early stages of pouring, and furthermore, there is a risk that cracks may occur due to the positive and negative pressure inside the nozzle that occurs during pouring.

The present invention solves the above-mentioned problems and provides a nozzle for continuous casting of flat slabs that is easy to manufacture and has improved strength such as thermal shock resistance, in response to an increase in the size of the nozzle.

[Means for Solving the Problems] The present invention provides a continuous casting nozzle for manufacturing slabs with a flat cross section, which is made of a molded refractory, has a flat cylindrical cross section, and has a screw-shaped uneven portion at one end. arranging one or more lower direct current mantles provided with , and having the uneven side of the lower direct current mantle face an upper fitting/distribution mantle which is similarly made of molded refractory and has a molten metal injection hole in the center, A continuous casting nozzle characterized in that the monolithic refractory is joined through the refractory so as to cover the uneven portion, and the outer circumferential surface of the monolithic refractory is tightly enclosed by an iron shell. It is.

[Function] The nozzle of the present invention is constructed as described above, and the lower direct current mantle and the upper fitting/distribution mantle of the nozzle are individually fired with molded refractories, and then joined with monolithic refractories. Furthermore, the outer circumferential surface of the monolithic refractory is tightly covered with an iron shell to supplement the refractory. The lower DC mantle and the monolithic refractory are closely connected via threaded concave and convex sections to prevent leakage, etc., and the monolithic refractory has a large area compared to the upper joint distribution mantle. Since the entire area is sealed, the connection between the distribution sleeve and the DC sleeve becomes stronger.

Therefore, compared to conventional integrated nozzles, each member has a simpler shape and is easier to manufacture. Members with less residual stress and distortion can be manufactured, and overall accuracy can be maintained. The structure can also be made stable against mechanical and thermal shocks. Therefore, it becomes easy to manufacture a wide nozzle, which was difficult in the past, and it is possible to cope with the increase in the size of the nozzle.

[Example] Embodiments of the present invention will be described below based on the drawings.

Figures 1 and 2 show a continuous casting nozzle 1 of the first embodiment.
(hereinafter referred to as a nozzle) is a longitudinal cross-sectional view showing the width direction and a cross-sectional view showing the thickness direction.

The nozzle l has a flat cylindrical shape as a whole, and a lower direct current mantle 2 made of molded refractory material, has a flat cylindrical cross section, and has a threaded concavo-convex portion 3 at the upper end at one end. Ru. An upper fitting/distribution mantle 4, which is similarly made of molded refractory material and has a molten metal injection hole 5 in the center, is disposed on the upper part, and the DC mantle 2 and distribution mantle 4 are made to face each other, and the monolithic refractory material 6 is placed in the uneven portion. 3 and the distribution mantle 4 from the outside. At this time, the inner surface of the monolithic refractory 6 is cylindrical to form a molten metal distribution space 7. Further, the entire outer circumferential surface of the monolithic refractory 6 is tightly covered with an iron skin 8 to supplement the monolithic refractory 6.

3 and 4 are a longitudinal sectional view in the width direction and a cross sectional view in the thickness direction of the nozzle 11 showing an embodiment of 9JA2.

This nozzle 11 is an example of the nozzle 1 of the first embodiment in which a plurality of lower direct current sleeves 2 (three in this embodiment) are arranged in the width direction of the nozzle 11 to form a wider nozzle. This drawing shows that by appropriately selecting the number of nozzles according to the width of the slab to be manufactured in this way, it is possible to cope with the increase in size.

As shown in FIGS. 3 and 4, a paste 9 made of the same material as the DC mantle 21 and the distribution mantle 4 is applied to the molten metal contact surface on the inner surface of the molten metal distribution space 7 formed of the monolithic refractory 6 to prevent inclusions. It is also preferable from the viewpoint of protecting the monolithic refractory 6 to coat the monolithic refractory.

As a method for covering the outer circumferential surface of the monolithic refractory 6 with the steel shell 8, the shell 8 may be covered after the monolithic refractory 6 is cast and molded, or the lower DC and the upper Mating/distribution mantle 4
It is also possible to hold the steel shell 8 in a predetermined position and then cast the monolithic refractory 6, but the latter method provides better adhesion with the steel shell 8, and the bonding is better. Becomes stronger.

Table 1 shows an example of the material components used as the monolithic refractory 6, and Table 2 shows an example of the paste 9 components to be applied to the inner surface of the monolithic refractory 6.

Table 1 Table 2 The molten metal thus injected from the tundish etc. through the molten metal injection hole 5 of the upper fitting/distribution pipe passes through the molten metal distribution space 7 and flows down the lower direct current 2. It is uniformly supplied in the width direction of the mold 20 shown in the figure and is cast. Furthermore, in the nozzle 11 of the second embodiment in which a plurality of lower DC currents 2 are provided, the injected molten metal is evenly distributed to each of the lower DC currents 2 within the molten metal distribution space 7, and is cast more widely in the mold 20. entered.

[Effects of the Invention] As explained above, the nozzle according to the present invention has a structure in which the lower DC part and the upper part are made of shaped refractories.
Since the distribution mantle is divided into parts and assembled by joining them with monolithic refractories, the shape of each segmented monolithic refractory is simplified and manufacturing is easy, resulting in a member with less residual stress and distortion. This makes it easy to maintain the accuracy of the nozzle, and it is also possible to manufacture a nozzle that is resistant to mechanical and thermal shocks, and has a stable structure that is resistant to cracking under the various stresses that occur during operation. becomes. Therefore, when applying to wide molds, the thickness of both the lower DC and
By simply forming multiple rows of lower DC, it is possible to provide a nozzle suitable for a sufficiently large continuous casting machine without taking any measures such as adding reinforcement. For the solid or monolithic refractories, heat-resistant materials suitable for each part can be selected, which not only improves the performance of the entire nozzle but also greatly contributes to reducing manufacturing costs.

[Brief explanation of drawings]

1 and 2 are a longitudinal cross-sectional view showing the width direction and a cross-sectional view showing the thickness direction of the nozzle of the first embodiment, and FIGS.
The figures are a longitudinal cross-sectional view showing the width direction and a cross-sectional view showing the thickness direction of the nozzle of the second embodiment, FIG. 5 is a side cross-sectional view showing an overview of a continuous casting machine for manufacturing flat slabs, and FIG. It is a perspective view showing an example of a conventional nozzle. 1.11... Nozzle, 2... Lower DC, 3...
Thread-shaped uneven portion, 4... Upper fitting/distribution mantle, 6...
・Unshaped refractory, 7... Molten metal distribution space, 8... - Iron skin, 9... - Inner surface coating paste

Claims (1)

[Claims] In a continuous casting nozzle for manufacturing slabs with a flat cross section, one or more lower direct current mantles are arranged, which are made of molded refractory material, have a flat cylindrical cross section, and have a screw-like unevenness at one end. , the uneven part side of the lower DC mantle is made to face the upper fitting/distribution mantle which is similarly made of molded refractory and has a molten metal injection hole in the center, and the refractory is placed so that the monolithic refractory covers the irregular part. 1. A continuous casting nozzle characterized in that the two are joined through a material, and the outer circumferential surface of the monolithic refractory is tightly enclosed by an iron shell.