JP2002153970A - Multi-layer structural molten metal pouring nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability by improving and uniformizing strength at the boundary part between layers in a pouring nozzle having multi-layer structure in the peripheral direction. SOLUTION: In the multi-layer structural pouring nozzle composed of concentrically layered different materials of refractories, the ruggedness part 5 is arranged in a row shape in the peripheral direction in the boundary part between the different kinds of material so refractories 3, 4 and both refractories 3, 4 are integrated by encroaching of the ruggedness part 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pouring nozzle for casting, and more particularly to a pouring nozzle having a multilayer structure.

[0002]

2. Description of the Related Art In continuous casting, a pouring nozzle (immersion nozzle, long nozzle, air seal pipe, etc.) is used as equipment for injecting molten metal from a ladle to a tundish or from a tundish to a mold.

[0003] Since the lower part of this type of pouring nozzle is immersed in the molten metal, a plurality of types of refractory materials having performance according to the purpose of use of the pouring nozzle are conventionally formed concentrically. It is made up of:

For example, as shown in FIG. 1 as a typical form, a basic part of a pouring nozzle 1 is made of a graphite-alumina refractory 2 and is immersed in a molten metal. The outer periphery of the required range is constituted by graphite-zirconia refractories 3 concentrically arranged on the outer periphery of an inner refractory 4 made of non-graphite.

[0005] As a known technique of the pouring nozzle configured as described above, JP-A-6-285613 (known example 1), JP-A-8-57601 (known example 2), and JP-A-9-33173. (Known example 3), JP-A-9-33
No. 174 (known example 4), Japanese Utility Model Application Laid-Open No. 2-38153 (known example 5), Japanese Utility Model Application Laid-Open No. 3-68962 (known example 6), and the like.

[0006]

However, the first known example is as follows.
The two types of refractories are combined by screwing refractories of different materials together with a taper screw. Since the two members are screw-connected to form a pouring nozzle, different types of materials are used. The refractory cannot be molded simultaneously (integrally molded), and because of the screw connection, the screw connection part is easy to loosen due to the difference in expansion and contraction of the two types of refractory during use, and it is difficult to guarantee the fixed state. There is a problem in durability.

[0007] The known example 2 is a pouring nozzle composed of a plurality of layers by laminating a refractory material to the inner body through a joint, and known examples 3 and 4 are wear rings of the inner peripheral portion. The tube is divided into four or six stages or an integral body,
Since the inner peripheral surface is coated with an amorphous refractory having a residual expansion property, it cannot be simultaneously molded with a plurality of types of refractories.

In the known example 5, since a protection ring on the outer periphery of the basic portion of the nozzle is screwed into a pouring nozzle having a multi-layer structure, the expansion of the two types of refractories is performed in the same manner as in the known example 1. In addition, the screw joint is easily loosened due to the difference in shrinkage, which again has a problem of durability.

Further, in the prior art 6, a slag line refractory is buried on the outer periphery of a portion corresponding to the slag line, but the configuration for the burial is not clear.

As described above, in the conventional multi-layer pouring nozzle, the compression strength of the molded product, springback, expansion and shrinkage behavior during firing or during use are different in each layer, so that the bonding strength at the boundary portion is low, There was a problem that cracks and skin separation tended to occur, resulting in poor durability.

SUMMARY OF THE INVENTION It is an object of the present invention to increase the strength of a boundary portion of a multilayer and to make the strength uniform so as to significantly improve the durability.

[0012]

According to the present invention, there is provided a multi-layer pouring nozzle comprising concentrically laminated refractories of different materials. An uneven portion is arranged in the circumferential direction of the portion, and both refractories are integrated by biting the uneven portion.

It is preferable that the refractories of the different materials be integrated by a cold isostatic press in view of improvement in strength at the boundary between the two refractories and ease of production.

The uneven portion may have an appropriate cross-sectional shape, but preferably has a trapezoidal cross-section so as to be strong against a force in the rotating direction, and one surface is formed of a boundary surface of the refractory. And the other surface has a saw-tooth shape with an inclined surface of 45 ° or less with respect to one surface of the adjacent convex portion, so that the structure can be tough against the radial force of both refractories. it can.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments shown in the drawings. The pouring nozzle according to the present invention has a basic part made of graphite-alumina or the like refractory 2 and an inner peripheral part made of a non-graphite refractory 4, similarly to the embodiment shown in FIG. Further, the outer periphery of the portion corresponding to the slag line below the basic portion is made of a refractory 3 such as graphite-zirconia.

In the present invention, FIG.
As shown in a cross-sectional view corresponding to -A, uneven portions 5 are arranged in a row at a predetermined pitch in the circumferential direction of the outer peripheral surface of the refractory 4 constituting the inner periphery, and the refractory 3 is concentrically arranged on the outer periphery. It is arranged.

The uneven portion 5 has a trapezoidal cross section as shown in an enlarged view in FIG.
, The height of the projection 5a is B, the width of the tip of the projection 5a is C, and the width between the roots of the adjacent projections 5a, 5a is D. ≧ B ≧ C ≧ D to A>B>C>
D, and the number N of the protrusions 5a is N ≧ 5.

FIG. 3 shows another embodiment of the uneven portion, which is a saw-tooth uneven portion 5 in cross section.

As shown in the enlarged view of FIG. 3B, the convex portion 5b of the concave and convex portion has one surface 5c at an angle α (a sharp angle) with respect to the boundary surface 4a of the refractory 4, and the other surface 5d is adjacent to the boundary surface 4a. Is formed at an angle β (a sharp angle) with respect to one surface 5c of the convex portion 5b.

The angle α is an acute angle smaller than 90 °, and the angle β is an acute angle smaller than 45 °. The relationship between the thickness A of the refractory 4 and the height B of the projection 5b is A> 2B.
It has been. The number N of the protrusions 5b is set to N ≧ 10.

The refractory 3 on the outer periphery is integrally formed with the refractory 4 on the inner periphery by a cold isostatic press. As a result, the refractory 3 on the outer periphery is hardly embedded in the uneven portion 5, and both refractories 3,
The contact area of No. 4 is increased to be firmly bonded.

In the case of the saw-toothed uneven portion 5 shown in FIG. 3, the refractory 3 on the outer periphery enters the surface 5c forming the acute angle α of the convex portion 5b, so that a stronger connection is achieved.

The shape of the uneven portion 5 is not limited to the above two examples, but may be an uneven portion having an appropriate sectional shape.

[0024]

As described above, according to the present invention, the refractory constituting the inner periphery of the pouring nozzle and the refractory disposed on the outer periphery thereof are arranged in the circumferential direction at the boundary portion. By joining through the uneven portion, the strength of the boundary between the refractory inside and outside can be increased, and the strength can be uniform without variation, and the stability at the time of use can be obtained, Slipping of the inner refractory can also be eliminated.

If the refractory on the inner periphery and the refractory on the outer periphery are integrally formed by cold isostatic pressing, the connection at the boundary can be made more reliable, and at the same time, the efficiency can be increased. It can be manufactured, and the yield can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a multi-layer pouring nozzle to which the present invention is applied.

2A and 2B show an embodiment of the present invention, wherein FIG. 2A is a cross-sectional view corresponding to AA in FIG. 1, and FIG. 2B is an enlarged view of a part thereof.

3A and 3B show another embodiment of the present invention, in which FIG. 3A is a sectional view corresponding to AA in FIG. 1, and FIG. 3B is an enlarged view of a part thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pouring nozzle 2 Refractory of a basic part 3 Refractory of an outer periphery 4 Refractory of an inner periphery 5 Uneven part 5a, 5b, 5A Convex part

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hidetaka Ogino 4-7-1 Kudankita, Chiyoda-ku, Tokyo Shinagawa White Brick Co., Ltd. F-term (reference) 4E004 FA10 FB10 4E014 DB01 DB03

Claims (4)

[Claims] In a pouring nozzle having a multi-layer structure in which refractories of different materials are concentrically laminated, irregularities are arranged in a circumferential direction at a boundary between refractories of different materials, and the irregularities are formed in a row. A multi-layer pouring nozzle characterized in that both refractories are integrated by penetration. 2. A multi-layer pouring nozzle according to claim 1, wherein said refractories of different materials are integrated by a cold isostatic press. 3. A pouring nozzle having a multilayer structure according to claim 1, wherein said uneven portion has a trapezoidal cross section. 4. The uneven portion has a sawtooth shape in which one surface forms an acute angle with respect to the boundary surface of the refractory, and the other surface has an inclined surface of 45 ° or less with respect to one surface of the adjacent convex portion. A pouring nozzle having a multilayer structure according to claim 1 or 2.