JPH07103658A - Water-cooled furnace wall structure of electric furnace - Google Patents

Abstract

PURPOSE:To carry out safe and economical operation with a high productivity while saving the energy in an electric furnace having a bottomed main body with a furnace bottom part and furnace walls and a furnace lid by a method wherein damage of refractory material at an upper end portion of an opening of the furnace walls is reduced and over-cooling in the electric furnace is prevented. CONSTITUTION:An electric furnace 1 has a main body 2 comprised of a furnace bottom 2a and furnace walls 2b and a furnace lid 3, and the refractory materials 2aa and 2ba at the furnace bottom and the furnace walls are lined at the inner circumferential surface of an iron plate 2c constituting the outer wall of the main body 2. Metallic water-cooled heat transfer pipes 2bb the number of which is as less as possible are arranged substantially over almost the entire circumference along the inner circumferential surface at the upper part of the furnace walls 2b and the refractory material 2ba is lined up to a place near the lower- most stage water-cooled heat transfer pipe 2bb.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a bottomed bottom composed of a furnace bottom and a furnace wall in order to melt and melt a main raw material mainly composed of metal raw materials and auxiliary raw materials necessary for refining, iron making, and steelmaking. In a conventional electric furnace having a refractory structure, which comprises an electric furnace body and a furnace lid, and a refractory material is lined on an inner peripheral surface of an iron shell forming an outer wall of the electric furnace body, In the conventional electric furnace having a water-cooling structure in which water-cooling heat transfer tubes are arranged in multiple stages above the lining refractory that extends toward the upper end edge of the furnace wall, the opening of the furnace wall of the electric furnace body It reduces the damage to the refractory at the upper end and reduces the heat energy loss that is taken away by the cooling water passing through the water-cooled structure inside the electric furnace body and by extension from the electric furnace, that is, overcooling the electric furnace. To prevent energy consumption and save energy while increasing economic efficiency and productivity. The relates to a water-cooled furnace wall structure for an electric furnace which allows operations.

[0002]

2. Description of the Related Art Refractory materials are used for melting and melting, iron and steel, and the main raw materials mainly composed of metal raw materials such as metal scraps, ferroalloys and ores, and auxiliary raw materials necessary for refining lime and coke. As shown in FIG. 6, a conventional electric furnace 21 having a refractory structure lined with is mainly provided with an electric furnace main body 22 (hereinafter sometimes simply referred to as a main body) and a furnace lid 23. It is composed of a furnace bottom 22a and a furnace wall 22b, has an open end surrounded by the furnace wall 22b and has a bottom, and the furnace wall 22b of the main body 22 constitutes the entire outer wall of the main body 22. The entire inner peripheral surface of the skin 24 was stamped or coated with a regular refractory brick 25 and optionally an irregular refractory (not shown) and lined. That is, the furnace wall 22b of the electric furnace body 22 is a regular refractory brick formed in a predetermined shape on the inner peripheral surface side of the iron shell 24 having a substantially ring-shaped cross section that constitutes the entire outer wall of the electric furnace body 22.
25 is continuously laminated on a regular refractory brick arranged at the bottom up to the upper edge of the opening and lined.

[0003] Such a fixed-shape refractory brick 25 is thermally expanded during the operation of the electric furnace 21, and the fixed-shape refractory bricks 25 that are adjacent to each other in the horizontal direction are in a state of being pressed against each other, which is difficult to move. In the fixed-shape refractory brick 25 of the furnace wall 22b, it is not fixed in the vertical direction to the inner peripheral surface side of the iron shell 24, but the downward load due to the weight of the fixed-shape refractory bricks 25 stacked above it. Since it is only working, the fixed-shape refractory bricks 25 arranged near the upper end of the opening of the iron shell 24 forming the entire outer wall of the electric furnace body 22 are very weak against the load acting upward. . Therefore, when the electric furnace 21 is operated, the fixed-shaped refractory brick is affected by the temperature inside the furnace which moves up and down.
25 the electric furnace body by repeating thermal expansion and contraction
The fixed-shape refractory brick 25 arranged near the upper end of the opening 22 has a drawback that it tends to fall off and be damaged because it moves a considerable distance in the vertical direction.

Further, when melting and melting the main and auxiliary raw materials, ironmaking, and steelmaking in the electric furnace 21, heating is performed with the furnace lid 23 closed, but the arc generated from the electrode causes Since the splash that splashes from the molten metal and slag in the furnace adheres to the furnace lid 23 and the fixed-shape refractory bricks 25 arranged near the upper end of the opening of the electric furnace body 22 and solidifies, a phenomenon occurs. When the lid 23 is lifted and opened, the fixed refractory brick 25 near the opening upper end of the furnace wall 22b of the electric furnace body 22 moves together with the furnace lid 23, and the fixed refractory brick 25 in that part falls off, and the remaining The fixed refractory brick 25 has a drawback that it tends to be subsequently dropped and damaged.

If the regular refractory brick 25 is damaged in this way, the iron shell 24 forming the entire outer wall of the electric furnace body 22 is exposed inside the main body 22, which is dangerous. Therefore, the regular refractory brick 25 is newly added. Since it is necessary to repair the furnace wall 22b for locally reconstructing 25, the workability is poor, and it is unsafe and uneconomical. Furthermore, at least during this troublesome repair work, it is natural that the electric furnace There is a drawback that productivity is reduced because 21 operations cannot be performed.

Next, the conventional electric furnace 31 having the water cooling structure is basically the same as the conventional electric furnace 21 having the refractory structure as shown in FIG. 7, but is different. The points will be clarified and explained below. This conventional electric furnace 31 mainly includes an electric furnace main body 32 and a furnace lid 33, the main body 32 is composed of a furnace bottom 32a and a furnace wall 32b, the furnace wall 32b of the main body 32 of the main body 32. The inner peripheral surface of the iron shell 34 constituting the entire outer wall was formed by stamping or coating a regular refractory brick 35 and, if necessary, an irregular refractory (not shown) on the inner peripheral surface. The refractory structure is different from the conventional electric furnace 21 in that a fixed-shape refractory brick 35 or the like is not used at a considerable distance downward from the upper edge of the opening in the furnace wall 32b, and the iron skin 34
The point is that it has a water-cooled furnace wall structure in which a large number of metal water-cooled heat transfer tubes 36 are arranged in series along the inner peripheral surface of the above.

Therefore, in the conventional electric furnace 31 having such a water-cooled structure, since the fixed refractory bricks 35 and the like are not used at all in such a distance, the amount of the refractory material which is also a consumable material is used. And its basic unit can be greatly reduced as a whole of the electric furnace 31, and not only the refractory cost can be reduced, but also all the drawbacks of the conventional electric furnace 21 having the refractory structure described above are eliminated. It has a great advantage. That is, since there is no fixed-shape refractory brick 35 or the like arranged at the upper end of the opening in the furnace wall 32b, it is naturally not damaged, and therefore the workability is poor even if it is local, and it is unsafe and uneconomical. Since no repair work is required, this repair work time can be operated and productivity can be improved.

However, even in the conventional electric furnace 31 having a water cooling structure having various advantages as described above,
The conventional electric furnace 21 having the refractory structure does not have the following drawbacks. 1) Since the water-cooled heat transfer tubes 36 made of metal are arranged in a considerably large number of stages and the water-cooled furnace wall structure is relatively long, there is a high risk of steam exposure due to leakage of cooling water, and safe operation is possible. There is a drawback in going. 2) Since it has a relatively long water-cooled furnace wall structure, the molten metal 39 and the slag layer 40 are
In the main body 32 where is held, and by extension, the heat energy loss from the entire electric furnace 31 is taken away, and a large amount of expensive electric power is consumed to make up for this loss. There is a drawback that you can not perform a regular operation. 3) In particular, the excessive cooling of the molten metal 39 and the slag layer 40 held inside the main body 32 can prevent the target suitable temperature control, and perform various refining to achieve the target good quality level. However, it is a drawback in the process of refining and making steel by accelerating the metallurgical reaction.

[0009]

The present invention is an advantage, rather than a drawback, in the conventional refractory-structured electric furnace 21, while the furnace wall 32b of the body 32 has a relatively long water-cooled furnace wall structure. On the contrary, for the electric furnace 31 of 1) to 3) above
The disadvantageous items described in Section 1 are eliminated by complementing both of them, and the refractory cost is reduced by reducing the amount of refractory used and its basic unit. Safe and uneconomical refractory repair work is unnecessary, heat energy loss that is removed from the electric furnace and carried away is reduced as much as possible, power consumption is saved, energy saving is aimed at, and the operating rate is increased. It is an object of the present invention to stably operate an electric furnace that is safe, economical, and has excellent productivity, and to melt and melt a high-quality metal melt as desired, to make a steel, and to make a steel.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies and studies to solve the above problems, and as a result, as a result, water cooling made of metal is performed along the upper inner peripheral surface of the furnace wall of the electric furnace body. If the heat transfer tubes are arranged over the entire circumference with a minimum number of steps of 2 or 4 and the refractory is lined up to the position near the water-cooled heat transfer tube at the lowest step, especially refractory It was clarified that damage and repair work related to it can be significantly reduced, at the same time it can prevent overcooling in the electric furnace, and stable, economical and highly productive electric furnace operation can be stably performed. Then, the present invention was completed.

[0011]

Embodiments of the water-cooled furnace wall structure of an electric furnace according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory plan view showing an embodiment of a water-cooled furnace wall structure of an electric furnace according to the present invention, and FIG. 2 is a cross-sectional view showing a main part near an upper end of an opening in a furnace wall structure of an electric furnace body according to the present invention. Front explanatory view, FIG. 3
FIG. 4 is a schematic cross-sectional explanatory view of another embodiment of the entire electric furnace provided with the water-cooled furnace wall structure of the electric furnace according to the present invention.

In the drawings, reference numeral 1 is an electric furnace for melting and melting main and auxiliary raw materials, ironmaking, and steelmaking, which has a tap hole 4, a slag opening, a working opening, etc., and a furnace bottom 2a and a furnace. It consists of an electric furnace body 2 composed of a wall 2b, and a furnace lid 3 having an electrode insertion opening through which an electrode 5 moves up and down. The furnace lid 3 is vertically moved and swung with respect to the upper end edge of the opening of the electric furnace main body 2 which is fixedly installed, and is openably and closably mounted. After opening the furnace lid 3 and charging the main and auxiliary raw materials into the internal space 2d of the electric furnace main body 2, the furnace lid 3 is placed and closed to energize the electrode 5 to melt the raw material with the arc. And it melts. At the time of this melting and melting, and although not shown, at the time of oxygen blowing, the splash 8 inevitably scatters from the molten metal 6 and the slag layer 7 toward the upper end of the opening of the furnace wall 2b and the furnace lid 3. Then, the molten metal 6 and the slag layer 7 are stored in the internal space 2d of the electric furnace main body 2, and after the predetermined ironmaking and steelmaking are finished, the molten metal is discharged from the taphole 4 to the outside of the electric furnace 1.

Such an electric furnace main body 2 has an iron shell 2c which constitutes the entire outer wall of the electric furnace main body 2, and along the upper inner peripheral surface of the cylindrical furnace wall 2b of the iron furnace 2c. The metal water-cooling heat transfer tubes 2bb through which the cooling water flows are arranged in a small number of stages as much as possible over substantially the entire circumference. As shown in FIG. 7 and described above, as compared with the conventional electric furnace 31 having the water-cooled furnace wall structure in which the metal water-cooled heat transfer tubes 36 are arranged in series in a considerably large number of stages, as compared with FIG. In the vicinity of the upper end of the opening in the furnace wall 2b of the electric furnace body 2 adopting the water-cooled furnace wall structure of the electric furnace according to the present invention shown in FIG. In this case, four stages of water-cooling heat transfer tubes 2bb are provided, and in any case, they are provided over the entire circumference in a minimum number of stages of 1 to 4 stages. Moreover, as shown in FIG. 2 and FIG. 3, the furnace wall refractory material (furnace wall shaped refractory brick) 2ba is lined up to a position near the bottommost water-cooling heat transfer tube 2bb in such a minimum number of stages. This is very important.

Explaining in more detail, the electric furnace body 2 is
As shown in Fig. 1, the furnace wall 2b of the iron skin 2c that constitutes the entire outer wall
Along the inner peripheral surface of the cylindrical upper part of the portion, a metal water-cooling heat transfer tube 2bb through which cooling water is passed is fixed over substantially the entire circumference of the iron shell 2c using a fixing metal fitting 2bc. . For example, this metal water-cooled heat transfer tube 2bb may be fixed by welding to the fixing metal fitting 2bc, while the fixing metal fitting 2bc is bolted to the iron shell 2c.
It suffices if it is fixed by an appropriate connecting means such as a nut.

As each metal water cooling heat transfer tube 2bb arranged near the upper end of the opening in the furnace wall 2b, a hollow portion through which cooling water is passed is formed, and as shown in FIG. It may be arranged along substantially the entire circumference along the inner peripheral surface side of the iron skin 2c, and is made of, for example, a metal curved in an arc shape in accordance with the entire inner peripheral surface shape of the iron skin 2c. It suffices that the bent pipe and the U-shaped pipe bent into a U-shape are joined by welding, and specifically, a steel pipe or the like made of ordinary steel or the like is used. In this way using concrete steel pipe,
It suffices that the steel pipes are arranged in an extremely small number of 1 to 4 and arranged in parallel vertically.

Water-cooled heat transfer tubes 2b arranged in four stages shown in FIG.
FIG. 4 shows an embodiment of an arrangement pattern in which b is arranged concentrically with respect to the central axis O of the electric furnace body 2 and in parallel in the vertical direction. As shown in FIGS. 1 and 2 and FIG. 4, the water-cooled heat transfer tube 2bb is concentrically divided into four equal parts with respect to the central axis O of the electric furnace body 2 and the inner peripheral surface of the iron shell 2c. In each of the sections divided vertically, the two or four stages of water-cooled heat transfer tubes 2bb are arranged by welding along the inner peripheral surface side of the iron shell 2c for each section. However, even if the water-cooled heat transfer tube 2bb is partially damaged, it is sufficient to replace the integrated water-cooled heat transfer tube 2bb with only the relevant damage section. It is preferable in terms of shortening and cost reduction, and efficiency and productivity in electric furnace operation.

Further, the water-cooling heat transfer tubes 2bb arranged in a very small number of stages are not only arranged as described above, but also shown in FIGS. 4 and 5 (a)-(c). As shown, iron crust 2c
It is preferable that the distances and are alternately arranged in two staggered rows. In order to reduce the heat energy loss that is taken away by the cooling water flowing through the water-cooled heat transfer tube 2bb from the electric furnace body 2 and, as a result, the electric furnace 1 as described above, the water-cooled heat transfer tube 2bb is reduced in number as much as possible. It is necessary to install it, but water-cooled heat transfer tubes are also installed in each stage.
The space around 2bb has a splash coating layer 9 formed by being filled with a splash 8 generated and scattered from the molten metal 6 and the slag layer 7 held inside the electric furnace body 2, It is also preferable in order to prevent excessive cooling due to the above and to protect and stably fix the water cooling heat transfer tube 2bb itself. Moreover, in FIG.
(a) to (c) show each embodiment with a typical arrangement pattern of the water-cooling heat transfer tubes 2bb arranged in a staggered two-row shape. Since the formed splash coating layer 9 is stably formed and held without falling off easily by being arranged in a shape, on the other hand, the splash coating layer 9 is not formed too thick and does not hinder the opening and closing of the furnace lid 3. is there.

As shown in FIGS. 2 and 3 and 5, in the water-cooled furnace wall structure of the electric furnace according to the present invention, the water-cooled heat transfer tubes 2bb are arranged in a staggered two-row configuration with a minimum number of stages. The furnace wall 2b excluding the water-cooled furnace wall structure is the inner peripheral surface of the iron shell 2c that constitutes the entire outer wall thereof, as in the case of the conventional electric furnace main bodies 22 and 32 shown in FIGS. 6 and 7 and described above. On the side, the furnace bottom fixed refractory brick 2aa formed in a predetermined shape is arranged while laying it on the furnace bottom 2a, and the water cooling heat transfer tube in the furnace wall 2b is continuously continuous on the bottom bottom refractory brick 2aa. Inside the 2bb, the lowermost water-cooling heat transfer tubes 2bb are sequentially stacked up to a position near the lowermost water-cooling heat transfer tubes 2bb, and the lower end of the lowermost water-cooling heat transfer tubes 2bb and the upper end of the uppermost furnace wall refractory brick 2ba are lined with a slight gap. Or be lined so that both ends are in contact with each other. That is, in the furnace wall 2b of the electric furnace main body 2 adopting the water-cooled furnace wall structure of the electric furnace according to the present invention shown in FIGS. 2 and 3, the length of the furnace wall refractory 2ba stacked from the furnace bottom 2a is In the furnace wall 32b of the conventional electric furnace 31 having the water-cooled furnace wall structure shown in FIG.
As compared with the length of the furnace wall refractory 35 stacked from the above, the cooling water can be used to line the length of the water-cooling heat transfer tubes 2bb as much as possible by limiting the number of steps to a minimum. This is important in order to reduce the heat energy loss carried away from the electric furnace body 2 and further from the electric furnace 1.

[0019]

When the electric furnace 1 having the water-cooled furnace wall structure of the electric furnace according to the present invention having the above-described structure is operated, the metal in the furnace wall 2b is made of metal rather than the conventional electric furnace having the water-cooled furnace wall structure. Since the water-cooling heat transfer tubes 2bb are arranged in as few stages as possible over almost the entire circumference, it is possible to reduce the thermal energy loss carried away by the cooling water that is passed through, which saves power consumption and saves energy. Can be achieved. Further, the water-cooled heat transfer tubes 2bb made of metal are arranged in two staggered rows, and the splash coating layer 9 is positively formed in the arrangement pattern portion in place of the conventional fixed-shape refractory bricks, so that the heat energy loss is reduced. Is further reduced, that is, excessive cooling in the electric furnace 1 is suppressed, and an energy saving effect can be achieved. Then, the splash coating layer 9 is stably formed and held without falling off easily, and the splash cooling layer 9 can more stably fix and protect the water cooling heat transfer tube 2bb itself.

Moreover, by arranging the metal water-cooling heat transfer tubes 2bb in a staggered two-row configuration as much as possible, it is possible to suppress the overcooling of the electric furnace 1 as described above, and the inside of the electric furnace main body 2 is suppressed. The target suitable temperature control of the molten metal 6 and the slag layer 7 held in the chamber can be carried out, and the molten metal 6 can be produced in pig iron or steel at a desired quality level without delay. In addition, the metal water-cooled heat transfer tubes 2bb are shortly integrated into each of the subdivided sections that are vertically concentrically divided into a predetermined concentric circle with respect to the central axis O of the electric furnace body 2 to allow the cooling water to pass therethrough. By allowing water, even if the water-cooled heat transfer tube 2bb is partially damaged,
Since it is only necessary to replace the short water-cooled heat transfer tube 2bb of the damaged section, the frequency and extent of damage should be minimized to ensure safe operation, and the time and cost for replacement and repair should be shortened and reduced. It is possible to improve efficiency and productivity in terms of operation.

On the other hand, the furnace wall refractory material (furnace wall shaped refractory brick) 2ba in the furnace wall 2b is formed around a water cooling heat transfer tube 2bb arranged according to the water cooling furnace wall structure of the electric furnace according to the present invention. The water-cooled furnace wall structure having a splash coating layer 9 is provided directly below the furnace, but the main and auxiliary raw materials are heated and melted and melted by the electrode arc to raise the temperature in the electric furnace 1. The upper end position of this furnace wall-shaped refractory brick 2ba in which the wall-shaped refractory bricks 2ba are thermally expanded and stacked is about to rise. However, since a heavy and high-strength water-cooled furnace wall structure exists just above this furnace wall-shaped refractory brick 2ba and a cooling action is exerted, such a rise is prevented, and the upper end of this furnace wall-shaped refractory brick 2ba is prevented. Since the part is fixed stably, the upper end of the part is prevented from falling off and being damaged. Of course, since the splash coating layer 9 formed at the upper end of the opening of the furnace wall 2b does not exist and the furnace wall fixed refractory brick 2ba does not exist, the upper end thereof is not dropped and damaged.

[0022]

The electric furnace having the water-cooled furnace wall structure according to the present invention configured as described above is an electric furnace having a conventional refractory structure furnace wall, and further a conventional water-cooled furnace wall structure portion. Comparing with the electric furnace having the above, various drawbacks of the electric furnace having the conventional water-cooled furnace wall structure as described in the above items 1) to 3) are solved and the object of the present invention is achieved. is there.

[Brief description of drawings]

FIG. 1 is an explanatory plan view showing one embodiment of a water cooling furnace wall structure of an electric furnace according to the present invention.

FIG. 2 is a front explanatory view showing a cross section of a main part near an upper end of an opening in a furnace wall structure of an electric furnace body according to the present invention.

FIG. 3 is a schematic cross-sectional explanatory view of another embodiment of the entire electric furnace provided with the water-cooled furnace wall structure of the electric furnace according to the present invention.

FIG. 4 is a diagram illustrating a water-cooled heat transfer tube that is concentrically arranged in parallel with a central axis of an electric furnace body that employs a water-cooled furnace wall structure for an electric furnace according to the present invention, and that is parallel to the central axis. For each of the sections that are vertically divided into four concentric circles and are divided, the state of being integrated and arranged in two staggered rows,
It is a perspective explanatory view showing an example of an arrangement pattern which is typically shown and arranged with the flow of the cooling water which is seen from the arrow.

FIG. 5 is a typical arrangement pattern of water-cooling heat transfer tubes arranged in two staggered rows in a water-cooling furnace wall structure of an electric furnace according to the present invention, and a splash coating layer formed around the water-cooling heat transfer tubes. FIG. 3 is an explanatory view of a main part showing a water-cooling structure part and a furnace wall refractory that extends to a position just below.

FIG. 6 is a front view showing a furnace wall of a refractory structure in a conventional electric furnace body.

FIG. 7 is a cross-sectional explanatory view schematically illustrating an entire conventional electric furnace including an electric furnace body having a water cooling structure and a furnace lid.

[Explanation of symbols]

 1 Electric Furnace 2 Electric Furnace Main Body 2a Furnace Bottom 2aa Furnace Bottom Refractory (Furnace Bottom Fixed Refractory Brick) 2b Furnace Wall 2ba Furnace Wall Refractory (Furnace Wall Fixed Refractory Brick) 2bb Metal Water-cooled Heat Transfer Tube 2bc Fixing Fixture 2c Iron Skin 2d Inner space of the electric furnace body 3 Furnace lid 4 Gate 5 Electrode 6 Molten metal 7 Slag layer 8 Splash 9 Splash coating layer O Central axis of the electric furnace body 21 Electric furnace of conventional refractory structure 22 Electric furnace body 22a Furnace Bottom 22b Furnace wall 23 Furnace cover 24 Iron shell 25 Standard refractory bricks 26 Hot water outlet 31 Electric furnace with conventional water-cooled furnace wall structure 32 Electric furnace main body 32a Furnace bottom 32b Furnace wall 32c Hot water outlet 33 Furnace lid 34 Iron skin 35 Fixed size Refractory bricks 36 Metal water-cooled heat transfer tubes (arranged in series) 37 Internal space of the electric furnace body 38 Electrodes 39 Molten metal 40 Slag layer 41 Splash

Claims (5)

[Claims] 1. A steel shell (2c) comprising an electric furnace body (2) comprising a furnace bottom (2a) and a furnace wall (2b) and a furnace lid (3), which constitutes an outer wall of the electric furnace body (2). ) On the inner surface of the furnace bottom and furnace walls (2a
a, 2ba) are lined in the electric furnace (1), the metal water-cooled heat transfer tubes (2bb) are minimized along the inner peripheral surface of the upper part of the furnace wall (2b) of the electric furnace body (2). A water-cooled reactor for an electric furnace characterized in that the furnace wall refractory (2ba) is lined up to a position near the water-cooling heat transfer tube (2bb) at the lowest stage while being arranged substantially all around the number of stages. Wall structure. 2. A steel shell (2) forming an outer wall of the electric furnace body (2).
The metal heat transfer tube (2bb) is attached to the inner peripheral surface of (c) with the fixing bracket (2bc).
The water-cooled furnace wall structure of the electric furnace according to claim 1, which is fixed by the. 3. The water-cooled heat transfer tubes (2bb) of each stage are curved along the inner surface shape of each section obtained by vertically dividing the inner peripheral surface of the iron shell (2c), and The water-cooled furnace wall structure for an electric furnace according to claim 1 or 2, wherein the water-cooled heat transfer tubes (2bb) in stages are connected. 4. The water-cooled heat transfer tubes (2bb) at each stage are arranged in two staggered rows in which the distances from the iron skin (2c) are different from each other. The water-cooled furnace wall structure of the described electric furnace. 5. The internal space (2d) of the electric furnace body (2) is faced,
Hold inside the electric furnace body (2) in the space around the water-cooled heat transfer tubes (2bb) arranged in each stage above the furnace wall refractory (2ba) lined in the furnace wall (2b) 5. A splash coating layer (9) formed by being filled with a splash (8) generated and scattered from a molten metal (6) and a slag layer (7) to be formed, according to any one of claims 1 to 4. Water-cooled wall structure of the electric furnace.