JPH0437444A - Nozzle for continuously casting strip - Google Patents

Abstract

PURPOSE:To contribute to reduction of manufacturing cost by fitting and holding a sticking part of a flat cylindrical state flat part, a pouring basin part at the upped part thereof and a sprue part at the upper part thereof from outer periphery with a holder. CONSTITUTION:The cylindrical body of nozzle 1 for continuously casting the strip is constituted as follows. That is, this is constituted with the flat part 1a having the prescribed pouring length and flat cylindrical cross section, the pouring basin part 1b introducing the molten metal into the flat part 1a stuck to the upper part thereof and the sprue part 1c stuck to the upper part thereof and pouring molten metal. Then, each of the stuck parts 3a, 3b are fitted and held from the outer periphery with the holder 4. Inner part of the flat part is expanded to the width toward lower direction, and contracting part is arranged at the upper part. By this method, stable operation can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a splittable pouring nozzle used in a twin-belt continuous casting machine for thin plates.

[Conventional technology]

As shown in the side cross-sectional view of FIG. 3, a twin-belt continuous casting machine for thin plates has rotating belts 20 facing each other and having a predetermined plate width.
Molten metal is injected from a nozzle 21 into a mold 20 formed by parts a and 20b, and the molten metal is ejected from below to continuously produce cast slabs 22 for thin plates.

Since the slab 22 manufactured here has a wide and flat cross-sectional shape, the molten metal poured into the mold 20 is uniformly supplied in the width direction within the mold 20 to ensure uniform quality. Therefore, the flat part 2 of the nozzle 21
The shape of 1a is a rectangular or flat cross-sectional shape as shown in the perspective view of FIG. Note that in the figure, 21b is a sump, and 21C is a sprue.

For example, JP-A-50-61332, JP-A-60-20
In the casting method using a belt-type continuous casting machine disclosed in Publication No. 3345, etc., the nozzle length is 1200 mm and the width is 45 mm.
A nozzle with a shape of 0 mm and a thickness of 30 mm 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 flat part 21a is also several mm-1.
Because it is limited to a thin thickness of several millimeters, it is extremely unstable from a structural and strength standpoint, and thermal shock resistance is also required. The materials used are fused silica or -
An alumina-graphite refractory used in molten steel injection nozzles for boat fishing is used, and the flat part 21a, pool part 21b, and melting part 21c are fired and manufactured as one unit.

(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 is complicated, so such nozzles are made of high-temperature fired refractories or If it is manufactured in an integrated manner 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 manufacture it, the thermal shock resistance will be poor. Therefore, there is a very 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 pressures inside the nozzle that occur during pouring.

The present invention solves the above problems and provides a nozzle for continuous casting of thin sheets that is easy to manufacture and has improved strength such as heat resistance of 15 m, coping with the increase in size of the nozzle.

[Means to solve the problem]

The present invention provides a nozzle for continuous casting of thin plates for manufacturing slabs with a flat cross section, and the present invention provides a cylindrical body of the nozzle having a flat part having a predetermined injection length and a flat cylindrical cross section, and an upper part of the flat part. Consisting of a sump part that is in close contact with the molten metal to guide the molten metal to the flat part, and a sprue part that is in close contact with the upper part of the tundish part and injects the molten metal, and each of the contact parts is fitted and held from the outer periphery by a holder. The nozzle for continuous casting of a thin plate is characterized in that the inside of the flat part is widened downward and a constricted part is provided at the upper part.

[For production]

The nozzle of the present invention is constructed as described above, and the flat part, the pool part, and the sprue part that make up the cylindrical body of the nozzle are each manufactured separately, and then assembled by fitting them into the holder. are each held by a holder.

Therefore, each member has a simpler shape and is easier to manufacture than a conventional integrated nozzle, and members with less residual stress and distortion are manufactured, and accuracy is maintained as a whole.

Furthermore, since the adhesion portion acts as a relief for thermal stress and strain applied from the outside, no residual strain remains as internal strain, and it is stable against mechanical and thermal shock.

Furthermore, in the nozzle of the present invention, the width of the molten metal inlet inside the flat part is widened downward, thereby avoiding the scattering of molten metal at the initial stage of pouring, so-called drooping swishing phenomenon, and allowing the molten metal to flow into the constricted part. We are trying to make it more uniform.

Traditionally, nozzles are manufactured by putting the powder raw material for the nozzle into a rubber outer frame, applying water pressure from the outside to mold it, and then removing the outer frame and firing it. Conventionally, the outer frame could not be removed after molding, so it could not be manufactured using this method. However, by manufacturing each nozzle member separately, it becomes easy to remove the outer frame of the flat portion having the inverted taper, making it possible to manufacture the entire nozzle.

〔Example〕

An embodiment of the present invention will be described below based on the drawings. 1st
The figure is a longitudinal cross-sectional view showing the width direction of a thin plate continuous casting nozzle (hereinafter referred to as the nozzle), and FIG. 2 is a cross-sectional view taken along the xx plane of FIG. 1 showing the thickness direction.

The nozzle 1 has a flat cylindrical shape as a whole, and the inside thereof forms an injection port 2 for molten metal. The nozzle 1 has, from the bottom, a flat part 1a, a sump part 1b that is in close contact with the top of the flat part 1a and guides the molten metal to the flat part 1a, and a sump part 1b.
A holder 4 is provided on the outer periphery so as to fit and hold the respective contact parts 3a and 3b. The injection port 2 of the flat portion 1a is widened downward and is formed to have a wide base, and a constricted portion 5 is provided at the upper portion. Further, reinforcing ribs 6 are attached to the central core portion to maintain the strength of the flat portion 1a and the gap between the injection ports 2.

The present nozzle 1 is constructed in this way, and when manufactured, the flat part 1a, the sump part 1b, the molten metal part 1c, and the holder 4 are manufactured by, for example, molding and firing using a fireproof material suitable for each part. 4, flat part 1a,
It is assembled by sequentially inserting and fitting the hot water reservoir part 1b and the hot water bath part IC. In addition, in order to improve the bonding and adhesion between parts,
Fillers or adhesives may be used in the gaps between the contact parts 3a and 3b and the holder 4, if necessary.

The molten metal injected into the sprue 1c from the tundish or the like flows down the sump 1b and the inlet 2 of the flat portion 1a, and is uniformly supplied in the width direction of the mold 20 shown in FIG. , is cast.

Further, in the initial stage of pouring, the molten metal is once uniformized in the width direction at the constriction portion 5 and flows down, thereby preventing the so-called sagging phenomenon caused by drooping and allowing the molten metal to flow down smoothly.

〔Effect of the invention〕

As explained above, the nozzle according to the present invention is manufactured by dividing the nozzle structure at appropriate locations, and is used by assembling the nozzle structure. Therefore, the shape of each divided member is simplified and manufacturing is easy. This makes it easier to manufacture parts with less residual stress and distortion, which makes it easier to maintain nozzle accuracy and improves mechanical and thermal stability. It is possible to manufacture a nozzle that is resistant to force E, and it also has a stable structure that does not easily break under the various stresses that occur during operation. Therefore, it is possible to provide a nozzle through continuous casting of a sufficiently large thin plate without increasing the thickness of the flat part or adding reinforcement, and since it is manufactured in parts, Since heat-resistant materials suitable for each member can be selected, the performance of the entire nozzle is improved, and it also greatly contributes to reducing manufacturing costs. Furthermore, since it is easy to manufacture a flat part with a widening injection port, the shattering phenomenon at the beginning of hot water supply is eliminated, and stable operation can be performed.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view showing the width direction of a nozzle according to an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along the X-X plane of Fig. 1 showing the thickness direction of the nozzle, and Fig. 3 is a thin plate continuous casting. FIG. 4 is a side sectional view showing an outline of the machine, and a perspective view showing an example of a conventional nozzle. 1.21... Nozzle, 1a, 21a... Flat part, 1 b, 21b... Pool part, 1 c,
21c - sprue part, 3a, 3b... close contact part, 4...
・Holder, 5... Aperture part, 6... Reinforcement lip, 20
... Mold, 20a, 20b... Rotating belt, 22
...Cast slab Figure 1 Figure 2

Claims (2)

[Claims] (1) In a nozzle for continuous thin plate casting that produces slabs with a flat cross section, the cylindrical body of the nozzle has a flat part with a predetermined injection length and a flat cylindrical cross section, and an upper part of the flat part. Consisting of a pool part that is in close contact and guides the molten metal to the flat part, and a sprue part that is in close contact with the upper part of the pool part and injects the molten metal, and each of the contact parts is fitted and held from the outer periphery by a holder. A nozzle for continuous casting of thin plates characterized by the following. (2) The nozzle for continuous thin plate casting according to claim (1), wherein the inside of the flat part is widened downward and a constricted part is provided at the upper part.