JPS586865B2 - Cooling plate that forms the inner wall of high-temperature furnaces such as arc furnaces - Google Patents

Description

Detailed Description of the Invention The present invention relates to a cooling plate that forms the inner wall of a high-temperature furnace such as an arc furnace. By forming a non-ferrous metal layer such as copper or bronze with excellent toughness and heat conductivity on the steel pipe, it is possible to prevent the steel pipe from becoming brittle due to carburization from the high-temperature cast iron side to the steel pipe side during furnace operation. In addition, even if cracks occur in the cast iron, the non-ferrous metal layer has toughness, so this can be prevented from spreading to the steel pipes. Since a groove is formed and the non-ferrous metal is poured into the groove after the cooling steel pipe is inserted, even if the steel pipe reaches a high temperature during casting, the steel pipe will not be carburized from copper or static copper. Therefore, it is no longer necessary to apply carburization inhibitor to the steel pipe or cool the steel pipe, which is required when directly casting the steel pipe into cast iron. Therefore, it is possible to cool the steel pipe while casting it into cast iron. An electric arc furnace, etc. that prevents the occurrence of an air gap between the steel pipe and cast iron, and prevents as much as possible the reduction in heat transfer rate from the steel pipe to the cast iron due to this air gap. The present invention relates to a cooling plate that forms the inner wall of a high-temperature furnace.

The furnace wall of an arc furnace is composed of an inner wall made of cast iron or cast steel in which a steel pipe through which a cooling fluid passes is embedded, and an outer wall called a steel skin or the like provided on the outside of this inner wall.

The heat generated inside the arc furnace is cooled by a cooling fluid flowing within the inner wall, so that the steel shell forming the outer wall does not overheat.

The present applicant previously provided a product in which the above-mentioned inner wall was divided and standardized under the trade name IPB for the purpose of reducing the man-hours for manufacturing and assembling the inner wall.

Figures 1A and 1B are a side sectional view and a front view of this IPB, and as shown in the figure, the IPBI is a rectangular plate made of cast iron with a predetermined thickness d1 width l and length l2, and the high temperature side of this plate Refractory bricks 3, 3, . . . are embedded at appropriate intervals in the surface 2, that is, the surface 2 on the core side.

On the other hand, inside the PB1, a steel pipe 4 through which a cooling fluid (water, etc.) passes is embedded over one surface of the IPBI.

In the illustrated example, the steel pipes 4 are arranged in a meandering manner parallel to each other in the width direction of the IPBI, and in particular, the folded portions 5, 5, . . . This protruding folded part 5 further penetrates the iron skin forming the outer wall of the arc furnace, protrudes to the outside of the arc furnace, and is fixed by welding or the like using elbows 6, 6... and straight pipes 7, etc. has been done.

In addition, there are bolt holes 8, 8 and 8 for mounting in the four corners of IPB1.
... has been drilled.

In this way, in the conventional IPB 1, a large number of folded parts 5, 5, etc. are protruded from the surface 9 on the side of the iron shell (not shown), and therefore, the iron shell that surrounds this IPB 1 has a substantially entire surface. It is necessary to form a hole for penetrating the folded portion 5, which results in a significant increase in the number of man-hours required for manufacturing the arc furnace.

Further, the fact that the folded portion 7 protrudes to the outside of the steel shell in this way has resulted in a significant deterioration of the appearance of the arc furnace.

The reason why the folded portion 7 has to protrude outside the IPBI is considered as follows.

That is, when manufacturing the IPB 1, first the refractory bricks 3 and 2 are appropriately placed in a mold, and the steel pipe 4 is placed in the mold.
molten cast iron is poured over the pipe, but during this pouring, the heat of the molten cast iron heats the steel pipe and reaches a high temperature, and the cast iron also contains a large amount of carbon. This is because carburizing occurs from the cast iron side to the steel pipe side, making the steel pipe brittle, and cracks are likely to occur due to carburization, especially in parts such as the folded part 7 where distortion occurs during welding.

In addition, not only during casting but also during furnace operation, IPB is heated by the heat inside the furnace and reaches a high temperature, so over many years of use, steel pipes are more carburized than cast iron, resulting in cracks in the steel pipes. There were also problems such as the occurrence of

In this way, when a crack occurs in the steel pipe, this crack successively spreads to the cast iron side that is in contact with the steel pipe, and there is a problem in that the cooling fluid eventually leaks.

Therefore, in order to prevent carburization of the steel pipe during casting, conventional methods have been to apply a carburizing inhibitor around the steel pipe or to cast cast iron while cooling the steel pipe. In IPB, a slight gap occurs between the steel pipe and the cast iron side, and the existence of this gap (air gap) significantly impedes heat transfer between the water flowing inside the steel pipe and the cast iron side. There was a problem.

Therefore, in view of the above-mentioned problems in the conventional IPB, the present inventors conducted intensive research to effectively solve the problems and came up with the present invention.

The object of the present invention is that unlike conventional cooling plates of this type in which steel pipes are directly cast into cast iron, there is no carburization of the steel pipes from molten cast iron during casting. It is no longer necessary to cool the steel pipe during manufacturing, and the gap between the steel pipe and cast iron that occurs when casting is performed while cooling the steel pipe is prevented, and the decrease in heat transfer rate due to this gap is reduced. Provided is a cooling plate forming the inner wall of a high temperature furnace such as an arc furnace, which can prevent the problem as much as possible.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The drawings are for explaining one embodiment of the present invention.
Figures A and B are side sectional views and front views of IPB, which is a conventional cooling plate, Figures 3 and 4 are side sectional views for explaining the manufacturing process of the cooling plate according to the present invention, and Figure 2A. , B are a side sectional view and a front view of an IPH which is a cooling plate according to the present invention.

As shown in FIGS. 2A and 2H, numeral 10 indicates an IPB which is an example of a cooling plate according to the present invention, and this IPB 1 has a thickness of d',
It is a rectangular cast iron or cast steel plate with length l1' and length l2', and its high-temperature side surface 11, that is, the furnace core side surface 11, has refractory bricks 12, 12... embedded at appropriate intervals. There is.

On the other hand, on the low-temperature side surface 13 of the PB 10, a groove 14 having a substantially U-shaped cross section is formed in a meandering manner as shown in FIG. The gap between the groove 14 and the steel pipe 14 is filled with a non-ferrous metal 16 having excellent toughness and heat conductivity, such as copper or bronze. Therefore, a layer of the non-ferrous metal 16 is formed around the steel pipe 15.

The steel pipe 15 has only its both ends 15a and 15b exposed,
All others are buried within the non-ferrous metal 16.

In manufacturing this IPB10, for example, the third
As shown in the figure, first, the refractory bricks 12.12.
... are arranged as appropriate, and a male mold 18 having a U-shaped cross section is supported, and molten cast iron 19 is poured into the gap between these molds to provide U-shaped grooves 14, 14... A cast plate is formed, and then, as shown in FIG. 4, a steel pipe 15 is inserted into the groove 14, and the toughness and heat conductivity of the molten copper, bronze, etc. excellent, th
Pour iron metal 16 to complete IPB10.

Further, without using the refractory 12, it is also possible to provide mere grooves or irregularities on the surface using steel studs or the like.

As described above, the IPB 10, which is the cooling plate according to the present invention, has a layer of non-ferrous metal 16 such as copper and bronze having excellent toughness and heat conductivity formed around the steel pipe 15, so that it can withstand high temperatures during furnace operation. The steel pipe 15 is carburized from the cast iron 19 side to the steel pipe 16 side, so that the steel pipe 15 does not become brittle, and even if a crack occurs in the steel pipe 15, the toughness of the non-ferrous metal 16 prevents this from spreading to the cast iron 19. , furthermore, a steel pipe 15 is placed in the groove 14.
By casting the steel pipe 15 with the non-ferrous metal 16, even if the steel pipe becomes hot during casting, the steel pipe 15 will not be carburized from copper, bronze, etc. It is no longer necessary to apply a carburizing inhibitor to the steel pipe or to cool the steel pipe, as is the case when casting into cast iron. By preventing the air gap from occurring, it is possible to prevent as much as possible the decrease in heat transfer rate from the steel pipe to the cast iron due to this air gap.

In addition, in the IPBIO cooling plate according to the present invention, since the non-ferrous metal 19 protects the periphery of the steel pipe 15 from carburization, the entire steel pipe 15 including bent parts and welded parts that are particularly susceptible to embrittlement due to carburization. can be buried in the IPBIO, and therefore, unlike the conventional IPB1, it is not necessary to drill a hole through the folded part 7 in the steel shell during installation, which greatly reduces the man-hours required for manufacturing this type of furnace. It is possible to improve the appearance at the same time.

In summary, the present invention exhibits the following excellent effects.

(i) In a cast cooling plate with cooling steel pipes embedded inside, a non-ferrous metal layer such as copper or bronze with excellent toughness and heat conductivity is formed around the steel pipes, so that the heat of the furnace during operation It is possible to prevent the steel pipe from becoming carburized and embrittled by castings such as cast iron or cast steel.

(11) By providing a non-ferrous metal layer with excellent toughness around the cooling steel pipe, even if a crack occurs in the steel pipe, this crack can be prevented from spreading to the surrounding casting parts.

(110) As with conventional cooling plates of this type, in which cooling steel pipes are directly cast into castings such as cast iron or cast steel, there is no carburization of the steel pipes during casting compared to the molten castings. It is no longer necessary to cool the steel pipe during manufacturing, and by casting the steel pipe while cooling it, it prevents gaps between the steel pipe and castings such as cast iron or cast steel, and reduces the heat transfer rate due to this gap. can be prevented as much as possible.

(iv) The cooling steel pipe can be easily attached and detached from the casting substrate, and maintenance and inspection of the cooling steel pipe is easy.

(V) Since the cooling steel pipe is installed in the groove of the cast board, both ends of the steel pipe can be left and buried in the board. It is possible to eliminate the need to drill holes for passing through the parts, and it exhibits excellent effects such as being able to greatly reduce the number of man-hours required for manufacturing this type of furnace.

[Brief explanation of the drawing]

The drawings are for explaining one embodiment of the present invention.
Figures A and B are side sectional views and front views of IPB, which is a conventional cooling plate, Figures 3 and 4 are side sectional views for explaining the manufacturing process of the cooling plate according to the present invention, and Figure 2A. ．． B is a side sectional view and a front view of IPB which is a cooling plate according to the present invention. In addition, in the drawing, 1 and 10 are cooling plates, 4 and 15 are cooling steel pipes,
16 is a non-ferrous metal layer.

Claims (1)

[Claims] 1. In a cooling plate in which a cooling steel pipe is embedded in a cast substrate, a groove is formed on one side of the substrate and cast, and the cooling steel tube is inserted into the groove of the cast substrate. The inner wall of a high-temperature furnace such as an arc furnace is formed by pouring molten nonferrous metal such as copper or bronze with excellent toughness and heat conductivity, and casting and embedding the steel pipe in the nonferrous metal layer. cooling plate.