JPS63119971A - Brick structure around nozzle part of ladle for molten steel - Google Patents

Abstract

PURPOSE:To prevent cracking of an upper inlet box brick by disposing the upper and lower box bricks around a nozzle and interposing sleeper bricks between the work bricks as well as the permanent bricks and upper inlet brick of a ladle proper for a molten steel. CONSTITUTION:The bottom of the ladle 1 proper for the molten steel is layered and fixed with two layers of the upper and lower permanent lining bricks 4, 5 consisting of agalmatolite bricks via heat insulating materials 3 on the inside (front) surface of a shell 2 and is lined with work bricks 6 consisting of refractory bricks of materials of 70% Al2O3 class on the innermost layer. The insert nozzle 12 is circumferentially enclosed by the upper and lower box bricks 9, 10 consisting of the refractory bricks of the materials of 90% Al2O3 class. The brick 10 is fixed to the heat insulating material 3 and the bricks 5. The brick 9 is interposed with the sleeper bricks 11 for preventing cracking and is integrally and mutually fixed to the bricks 4, 6 and directly to the brick 10. The pressing force generated by a difference in the coefft. of thermal expansion between the bricks 6 and the bricks 4, 5 is received by the sleeper bricks 11 and the generation of the lateral cracking by the shearing stress of the brick 9 is prevented.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention provides a ladle for molten steel such as a ladle or a tundish.
This relates to the brick structure around the insert nozzle installed in the bottom of the pot.

(Prior Art) As shown in Figure 3, the bottom of a ladle for molten steel such as a ladle or tundish is covered with an iron skin (2).
2) has a structure in which two layers of permanent tension bricks (4) and (5) are applied to the inner surface (top surface) of the structure via a heat insulating material (3), and the innermost layer is covered with work bricks (6). It has become.

In these brick layers, permanent tension bricks (4) (5)
The reason why it is formed into two layers is to ensure the thickness and also to shift the joints of the upper and lower brick layers so that they do not overlap, making it difficult for molten steel to reach the steel skin (2) from the insulation material (3) through the joints. This is to protect the heat insulating material (3), etc., and to reduce costs by reducing the amount of replacement if the permanent brick (41 (5)) is damaged and needs to be replaced.

An insert nozzle (2) for injecting molten steel is provided at a suitable location on the bottom of the pot constructed as described above, but conventionally, the upper and lower chamber bricks (9) α are placed around this insert nozzle (b). The upper masonry brick (9) is fixed in contact with the end faces of the work brick (6) and the permanent tension brick (4), and the lower phase brick αω is surrounded by the permanent tension brick (5) and the insulation material (3). ) has a structure in which it is fixed in contact with the end face of the

(Problem to be Solved by the Invention) However, the upper and lower cell bricks (9) αω are made of Al1 (h is 90% class) refractory bricks from the viewpoint of maintaining erosion resistance. Brick (6) is Al2
We use refractory bricks with a 70% class O.
Since the expansion coefficient is larger than that of the square brick (9) α1 and the permanent tension brick (4) and (5) are made of waxite brick from the point of view of cost, the stress due to the difference in the expansion coefficient of these bricks is
Shearing stress is generated in the upper masonry brick (9) directly acting on the upper masonry brick (9) at the boundary between the work brick (6) and the permanent tension brick (4), resulting in transverse cracks (al).

As a result, the upper masonry brick (9) cracks and separates from the workpiece brick (6), which flows out with the molten steel and has a negative impact on the product, as well as increasing the number of repairs to the pot and shortening its lifespan. was there.

The present invention aims to solve these problems by providing a brick structure around a nozzle in a ladle for molten steel.

(Means for Solving the Problems) In order to achieve the above object, the brick structure around the nozzle in the ladle for molten steel of the present invention is as shown in the drawings corresponding to the embodiments. ) The upper and lower phase bricks (9) α are arranged around the molten steel insert nozzle (2) provided at the bottom of the molten steel ladle (1), and the end faces of the work bricks (6) and permanent tension bricks (4) of the main body of the molten steel ladle (1) This is characterized in that a pillow brick αυ for preventing cracking of the masonry brick is interposed between the upper masonry brick (9) and the outer peripheral surface of the upper masonry brick (9).

(Function) The work brick (6) is broken by the high heat of the molten steel contained in the pot.
The and permanent tension bricks (4) expand at different expansion rates, but the pressing force due to this expansion is fully received by the pillow brick αυ, and a uniform pressing force is applied to the outer periphery of the upper masonry brick (9). This prevents shear stress from being transmitted to the upper masonry brick (9).

(Example) To explain the embodiment of the present invention with reference to the drawings, (1) is mainly a ladle for molten steel such as a ladle or tundish, and the bottom part is the inner surface (upper surface) of the iron shell (2) stretched on the surface side. ) insulation material (3)
The upper and lower permanent tension bricks (4
) (5) is layered, and the innermost layer has AlzOi 7
Work brick (6) made of firebrick of 0% class material
It is made by being stretched.

(7) is a hole for installing a nozzle, which is rectangular in plan and penetrates through the bottom of the main body (1) for molten steel, and extends from the work brick (6) to the lower end of the upper permanent tension brick (4). The part of the lower layer extending from the permanent brick (5) to the lower end of the insulation material (3) is formed to have a small diameter so as to protrude into the nozzle mounting hole (7). The upper surface of the end of the permanent brick (5) is formed into a step (8).

(9) αφ is 81□0. The upper and lower phase bricks are made of refractory bricks with a material of 90% class, and the lower phase brick α1 is the inner peripheral end surface of the insulation material (3) exposed in the nozzle installation hole (7) and the permanent tension brick (5) in the lower layer. The outer circumferential surfaces thereof are brought into close contact with each other over the entire surface and are fixed together, and the upper masonry brick (9) is integrally laminated on the upper surface of this lower phase brick a@.

The outer peripheral surface of the upper masonry brick (9) and the permanent tension brick (4) on the upper layer side
) and the exposed inner peripheral end surfaces of the work brick (6), a certain space is provided, and a rectangular cylindrical frame-shaped pillow brick αυ made of the same material as the work brick (6) is interposed in this space. , the inner circumferential surface of the pillow brick αυ is completely brought into close contact with the outer circumferential surface of the upper masonry brick (9), and the outer circumferential surface is attached to the upper permanent tension brick (4).
) and fully adhere to the inner peripheral end face of the work brick (6),
It is fixed.

The hammer is an insert nozzle attached to the inner peripheral surface of the upper and lower phase bricks (91Ql).

When in use, this insert nozzle (2) is closed by a gate valve (not shown) and the molten steel is contained in the pot, but the workpiece brick (6
) and permanent tension brick (41 (51 expands in the plane direction).

At this time, as mentioned above, the expansion rates of the work brick (6) and the permanent tension bricks (4) and (5) are different, and the expansion causes a pressing force toward the upper masonry brick (9). Brick (9), work brick (6) and permanent tension brick (4)
Since a pillow brick αD is interposed in between, this pillow brick αυ
receives the pressing force due to the expansion of the work brick (6) and the permanent tension brick (4), and transmits it to the upper masonry brick (9) as a uniform pressing force over the entire surface. This prevents the occurrence of transverse cracks due to shear stress. That is, since the pillow brick αυ is softer than the square brick, it deforms without cracking and absorbs the expansion.

(Effects of the Invention) As described above, according to the brick structure around the nozzle part of the ladle for molten steel of the present invention, upper and lower chamber bricks are arranged around the molten steel insert nozzle provided at the bottom of the main body of the ladle for molten steel, and Pillow bricks are interposed between the end surfaces of the work bricks and permanent tension bricks that are the main body of the ladle and the outer circumferential surface of the overlay bricks to prevent the formation of cracks in the masonry bricks, so that the high heat of the molten steel stored in the ladle is Therefore, the work brick and the permanent tension brick expand at different expansion rates, but the pressing force due to this expansion is completely received by the pillow brick and transmitted as a uniform pressing force to the outer periphery of the overlay brick, It is possible to prevent shear stress from occurring in the overlay bricks, therefore, cracks do not occur in the overlay bricks, the number of repairs of the pot can be reduced, and the service life is greatly improved. It can be used for a long period of time.

[Brief explanation of the drawing]

1 and 2 show embodiments of the present invention.
The figure is a vertical front view of the bottom of the pot, and the second figure is its plan view.
FIG. 3 is a schematic longitudinal sectional front view showing a conventional brick structure. (1) Main body of ladle for molten steel, (41(5) Upper and lower permanent tension bricks, (6) Work bricks, (9) αφ...
・Upper and lower square bricks, αυ... Pillow bricks, (2)... Insert nozzle. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] Upper and lower cell bricks are arranged around the molten steel insert nozzle provided at the bottom of the main body of the ladle for molten steel, and a cell is installed between the end surfaces of the work bricks and permanent tension bricks of the main body of the ladle for molten steel and the outer peripheral surface of the upper cell brick. A brick structure around a nozzle part in a ladle for molten steel, characterized in that a pillow brick is interposed to prevent the occurrence of cracks in the bricks.