JP2000292072A - Furnace wall of arc furnace and water-cooled panel for furnace cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a furnace wall of arc furnace and a water-cooled panel for furnace cover in which the lifetime of furnace equivalent to or better than that of a water-cooled panel having steel plate welding structure, steel pipe structure, cast copper structure or copper plate welding structure can be ensured while reducing heat loss and power for supplying cooling water. SOLUTION: In the furnace wall of arc furnace and the water-cooled panel for furnace cover, a plurality of refractory bricks 2 arranged in a plurality of rows at a constant interval with the end face being exposed to the furnace wall are cast with cooling water pipes 3 arranged between the rows of refractory bricks 2. The refractory brick 2 may be provided a taper 8 such that the width thereof on the inner end face of the furnace is smaller than that on the opposite end face, or a buffer material 7 may be provided between the refractory brick 2 and the contact face with a casting, or the inner surface of the furnace may be protruded partially 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the dissolution of metallic materials,
The present invention relates to a furnace wall provided in a furnace of an arc furnace used for refining molten metal and a water cooling panel for a furnace lid.

[0002]

2. Description of the Related Art Until the early 1970's, an arc furnace used for melting metal materials and refining molten metal has a furnace body lined with a refractory inside a steel shell, and a furnace lid having a circular shape called a furnace lid frame. Refractory was used in the shape of an arch inside the metal frame. However, from the late 1970's, as the size and power consumption of arc furnaces for the purpose of improving productivity increased rapidly, the amount of wear of refractories used for furnace bodies and furnace lids increased remarkably, It has been problematic to increase the cost of refractories and to increase downtime for refractory repair.

[0003] In order to solve these problems, in order to extend the life of refractories and minimize the decrease in the thermal efficiency of the arc furnace, a furnace formed by casting a cooling water pipe and bricks in a cast iron or copper casting is used. A body cooler was proposed.
-118635). However, in the cooling structure, since the furnace inner surface temperature of the cast iron casting constituting the cooler body reaches 1000 ° C. or more, cracks due to thermal stress and changes in the structure of the casting due to the use of several hundred to 1,000 charges are caused. Embrittlement occurs, which causes the casting to wear and cause the problem that the cast bricks fall off.In addition, cracks generated on the casting surface propagate to the cooling water piping, causing water leakage. Sometimes it happened. Further, the copper casting has higher ductility and does not undergo structural change as compared with the above-mentioned cast iron casting, so that wear and tear do not occur rapidly. However, since the brick is cast inside the panel inside the furnace and the pipes are arranged on the back side of the brick, the temperature of the furnace inside end surface becomes high, causing a problem that the brick is rapidly worn. In addition, as the thickness of the panel body increases, the weight increases, and a copper casting whose material cost is extremely large as compared with cast iron is particularly expensive.

Further, in order to solve these problems, low-melting metals such as copper and aluminum are cast around a cooling water pipe in a radial direction so as to improve the cooling capacity and cracks generated on the casting surface. A method has been proposed for preventing the propagation of germs (see Japanese Utility Model Laid-Open No. 29798/1981). According to this method, it has been calculated that the furnace inner surface temperature of the casting constituting the cooler body can be suppressed to about 500 ° C. However, if slag does not adhere to the casting surface,
Alternatively, if a cooler is installed in a place with a high heat load that is difficult to adhere, the surface temperature will reach 1000 ° C. or more, and it will not be possible to solve the structural change of the casting, cracks, etc., and the cooling water Since a low-melting-point metal different from the material of the cooler body is cast around the pipe, the manufacturing process is complicated, and there is also a problem that the cost increases.

[0005] Due to the problems such as structural change and cracking of the casting, caster coolers of such a configuration have not become widespread, and at present, steel plate welding which does not have a refractory material on the inner surface side of the furnace is performed. Coolers with structures, steel piping structures, copper castings or copper plate welded structures, so-called water-cooled panels, are commonly used, and are effective in reducing the consumption of refractory materials even in large-sized, high-power arc furnaces. (JP-A-51-97506, JP-A-56-666)
No. 80 and Japanese Utility Model Publication No. Sho 56-45800).

[0006]

In the above-mentioned technology, a water-cooled panel having a steel plate welded structure, a steel piping structure, a copper casting or a copper plate welded structure having no refractory material on the inner side of the furnace is installed in the furnace. While reducing arc furnace refractory wear and cost and reducing downtime for repair of refractory, the water-cooled panel protects the panel body because it has no refractory on the inner side of the furnace. Therefore, there is a problem that a large amount of cooling water is required to perform cooling, heat loss due to the cooling water and pump power for supplying the cooling water increase.
For this reason, as the demand for improving energy efficiency and reducing carbon dioxide gas to prevent global warming has increased in recent years, heat loss due to cooling water and cooling There was a need for a water-cooled panel that could reduce the pump power required to supply water.

[0007] Furthermore, a cooler for a furnace body in which a cooling water pipe and bricks are cast into a casting that has been proposed in the past (Jpn.
No. 118635), there is a problem that cracks due to thermal stress and embrittlement due to a change in the structure of the casting occur, which progresses, wears the casting, and falls off the cast brick. . Further, the copper casting does not cause cracking due to thermal stress and embrittlement due to a change in the structure of the casting, but has a problem that the inner end face of the brick furnace is not cooled and rapidly wears out.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is intended to reduce the heat loss and the power for supplying cooling water, and to shorten the life of a steel plate having no refractory material on the inner side of the furnace. An object of the present invention is to provide a water cooling panel for a furnace wall and a furnace lid of an arc furnace, which can secure a water cooling panel having a structure, a steel piping structure, a copper casting, or a copper plate welding structure equal to or more than a water cooling panel.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a plurality of rows of refractory bricks are arranged at regular intervals in a furnace wall and a water-cooled panel for a furnace lid so as to expose an end face to the inside of the furnace. It is characterized in that the pipe is provided between the rows of refractory bricks by casting.

[0010] In the above structure, the refractory brick may be cast in such a manner that an inner end face of the refractory brick projects from the casting surface.
Provide a taper so that the width of the inner end face of the refractory brick is smaller than the width of the inner end face of the refractory brick, form the corner of the inner end face of the refractory brick opposite the furnace in an arc shape, and contact the refractory brick with the casting. The cushioning material can be arranged between the surfaces and a part of the furnace inner surface of the casting can be formed in a convex shape.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a front view of a water-cooling panel for a furnace wall of the present invention, FIG. 2 is a cross-sectional view of a water-cooling panel for a furnace wall of the present invention, and FIG. It is sectional drawing which shows the state which incorporated the water cooling panel into the furnace wall.

In the water cooling panel 1 for the furnace wall and furnace lid of the arc furnace of the present invention, the cooling water pipe 3 integrated with the water supply / drain pipe 4 is provided between the rows of the refractory bricks 2 and is cast. The distance from the cooling water pipe 3 to the furnace inner surface of the casting constituting the panel body 1 is short, and the furnace inner surface of the casting can be efficiently cooled.

The inner end face of the refractory brick 2 cast in the water-cooled panel 1 protrudes inward from the casting surface of the water-cooled panel 1. For this reason, the furnace inner surface of the water-cooled panel becomes uneven, so that the in-furnace melt 6 such as slag can be stably adhered to the surface of the water-cooled panel 1. The in-furnace melt 6 such as slag that has adhered often has the same heat insulation properties as the refractory brick 2 cast in the water-cooled panel 1, thereby protecting the water-cooled panel 1 and reducing heat loss. .

Refractory brick 2 cast in water-cooled panel 1
Is provided with a taper 8 so that the width of the inner end face of the furnace is smaller than the width of the inner end face of the counter furnace, so that the refractory bricks 2 bite into the water-cooled panel 1 to prevent the refractory bricks 2 from falling off. I have. Further, the refractory brick 2 reaches a high temperature due to the heat load in the furnace, and the end face inside the furnace is restrained by the casting constituting the water-cooled panel 1, and thermal stress is generated.
In particular, the corners of the inner end face of the reaction furnace where stress is concentrated are formed in an arc shape to reduce thermal stress.

A buffer 7 such as ceramic fiber or glass wool is wound around the refractory brick 2 cast in the water-cooled panel 1 to absorb the thermal expansion of the casting and the refractory brick 2 constituting the water-cooled panel 1. In addition, the compressive stress acting on the casting and the refractory brick 2 is reduced.

A part of the furnace inner surface of the water-cooled panel 1 is formed with a protrusion 5 in a convex shape, and the protrusion 5 is a refractory brick 2 whose furnace inner end surface protrudes from the surface of the water-cooled panel 1 in the furnace direction.
When the projecting portion of the inner end face of the refractory brick 2 falls off due to the collision of the scrap injected into the arc furnace, the projecting portion of the inner end face of the refractory brick 2 is replaced with a slag furnace. The inner melt 6 is stably held. In addition,
9 is a thermocouple for measuring the furnace inner surface temperature.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A water-cooling panel for a furnace wall of an arc furnace according to the present invention is installed in an arc furnace, and two of a plurality of conventional water-cooling panels having a steel piping structure having no refractory material on the inner surface side of the furnace are used. The arc furnace was replaced with a water-cooling panel for the wall of the arc furnace according to the present invention, and the amount of heat removed by the cooling water was compared. A thermocouple was installed to measure the surface temperature inside the furnace of the cast iron of the water-cooled panel.

The amount of heat removed by the cooling water per charge during operation of the two types of water-cooled panels is as shown in FIG.
The heat removal by the cooling water of the water cooling panel for the furnace wall of the arc furnace according to the present invention is about half of that of the existing water cooling panel, and the inside temperature of the furnace of the water cooling panel changes with the progress of the structural change of the cast iron of the water cooling panel. Does not reach 700 ° C to start. 10
The application of more than 00 charges does not change the structure of the casting of the panel main body 1 and does not cause the wear or falling off of the refractory brick cast in the water-cooled panel.

In the conventional structure, the temperature inside the furnace of the cast iron or cast steel constituting the water-cooled panel is about 1000 ° C.
However, in the water-cooled panel according to the present invention, the inner surface temperature of the cast iron became 700 ° C. or lower (see FIG. 5). In the case of cast iron or cast steel, since there is a transformation point near 700 ° C., when the transformation point is exceeded, a structural change or a decrease in strength occurs. In the water-cooled panel according to the present invention,
Since the furnace inner surface temperature of the cast iron can be suppressed to 700 ° C. or less, it is possible to prevent a structural change and accompanying wear. In addition, the improvement of the cooling capacity lowers the temperature of the furnace inner end face of the refractory brick, so that the life of the brick can be extended.

[0020]

The effects of the present invention are as follows.

(1) Since the furnace wall of the arc furnace and the water-cooled panel for the furnace lid are exposed to heat radiation from the arc and high-temperature gas, conventionally, a refractory brick is exposed inside the furnace with one end exposed inside the furnace. In the present invention, the cooling water pipe was cast inside the refractory brick, that is, inside the anti-furnace, but in the present invention, the cooling water pipe is provided between rows of The distance from the water pipe to the inside surface of the castings and bricks constituting the water-cooled panel is short, and the inside surfaces of the castings and bricks can be efficiently cooled.

(2) In the water-cooled panel according to the present invention, since the cooling water pipe is disposed between the refractory bricks, it is thinner and lighter than the conventional water-cooled panel in which the refractory brick and the cooling water pipe are cast. Can be achieved. Therefore, it is possible to increase the furnace volume of the arc furnace by reducing the thickness, or to reduce the size of the furnace body when securing the same furnace volume, and to reduce the cost of the water-cooled panel by reducing the weight. Can be reduced. Since the material cost of the copper casting is higher than that of the casting, the cost reduction by weight reduction is particularly remarkable for the copper casting.

(3) In the present invention, the refractory brick cast in the water-cooled panel has a furnace inner end surface projecting from the casting surface of the panel body in the furnace direction. Thus, it becomes possible to stably adhere the furnace melt such as slag to the surface of the water-cooled panel. Since the attached melt in the furnace such as slag often has the same heat insulation property as the refractory brick cast in the water-cooled panel, it is possible to protect the water-cooled panel and reduce heat loss.

(4) In the present invention, the refractory brick cast into the water-cooled panel is provided with a taper so that the width of the furnace inner end face is smaller than the width of the counter furnace inner end face. Is intruded into the casting that is the panel body, and the refractory brick can be prevented from falling off.

(5) In the present invention, the corners of the inner end face of the refractory brick opposite to the furnace are formed in an arc shape to relieve thermal stress, and at the same time, the water-cooled panel is formed by wrapping a cushioning material around the refractory brick. It absorbs the thermal expansion of the constituent castings and refractory bricks and reduces the compressive stress acting on the castings and refractory bricks.

(6) In the present invention, since a convex protrusion is formed on a part of the inner surface of the furnace of the water-cooled panel, the protrusion has a furnace inner end surface protruding inward from the surface of the water-cooled panel. It exhibits the same effect as the refractory brick, especially when the protrusion on the inner end of the furnace of the refractory brick falls off due to the collision of the scrap put into the arc furnace, the protrusion on the inner end of the furnace of the refractory brick. Instead, the melt in the furnace such as slag can be stably held.

[Brief description of the drawings]

FIG. 1 is a front view of a water cooling panel for a furnace wall according to the present invention.

FIG. 2 is a cross-sectional view of the water cooling panel for a furnace wall according to the present invention.

FIG. 3 is a cross-sectional view showing a state where a water-cooling panel for a furnace wall according to the present invention is incorporated in a furnace wall.

FIG. 4 is a cross-sectional view showing a temperature distribution when a conventional water-cooled panel for a furnace wall is used.

FIG. 5 is a cross-sectional view showing a temperature distribution when the water-cooling panel for a furnace wall of the present invention is used.

FIG. 6 is a graph of heat loss due to cooling water per charge of a water-cooling panel for a furnace wall of the present invention and an existing water-cooling panel around the panel when the water-cooling panel for a furnace wall of the present invention is applied to a DC electric furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water-cooled panel 2 Refractory brick 3 Cooling water pipe 4 Supply / drain pipe 5 Projection 6 Melt in furnace such as slag 7 Buffer material 8 Taper 9 Thermocouple

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K045 AA04 BA01 MA04 RA06 RA09 RA16 4K051 AA05 AB03 AB09 DA00 HA04 HA06

Claims (6)

[Claims] 1. A cast iron, cast steel or copper cast water-cooled panel installed on a furnace wall and a furnace lid of an arc furnace, comprising a plurality of rows of refractory bricks arranged at regular intervals so as to expose end faces inside the furnace. A water-cooling panel for an arc furnace wall and a furnace lid, wherein a cooling water pipe is cast between rows of refractory bricks. 2. The water-cooled panel for an arc furnace furnace wall and furnace lid according to claim 1, wherein the furnace inner end surface of the refractory brick is cast so as to protrude from the casting surface. 3. A furnace wall and a furnace lid of an arc furnace according to claim 1, wherein a taper is provided so that a width of a furnace inner end face of the refractory brick is smaller than a width of a non-furnace inner end face. For water cooling panel. 4. The refractory brick according to any one of claims 1 to 3, wherein a corner of the inner end face of the refractory brick is formed in an arc shape.
Item 8. A water-cooled panel for a furnace wall and a furnace lid of the arc furnace according to the above item. 5. The cushioning material according to claim 1, wherein a cushioning material is disposed between the contact surface between the refractory brick and the casting.
Item 8. A water-cooled panel for a furnace wall and a furnace lid of the arc furnace according to Item. 6. The water-cooled panel for an arc furnace furnace wall and furnace lid according to claim 1, wherein a part of the furnace inner surface of the casting is formed in a convex shape.