JP4073925B2 - Metallurgical furnace stave - Google Patents

Description

  The present invention relates to a stave used in a metallurgical furnace such as a blast furnace.

  The furnace wall structure of the blast furnace is provided with a stave (cooling stave) with an internal cooling mechanism inside the iron skin, and the refractory inside the furnace is held inside this stave. In operation, the refractory inside the furnace falls off the stave due to damage or the like, and the stave is directly exposed to the inside of the furnace. Therefore, the stave must be able to withstand the heat load inside the furnace even after the refractory in the furnace falls off.

  Conventionally, cast iron is widely used as a blast furnace stave, and among them, a structure in which a cooling pipe is casted with cast iron is generally used. However, such a cast iron stave has a low cooling ability due to the low thermal conductivity of cast iron. For this reason, especially in the high heat load area at the bottom of the blast furnace where the molten slag exists (morning glory, upright part, shaft lower part), high thermal stress is easily generated in the stave body, and this crack propagates to the cooling pipe. It is easy to cause a water leakage accident.

  In order to prevent such breakage of the cooling pipe, it is common to make the cooling pipe and the casting part non-fused. However, in such a structure, the cooling ability of the stave is further lowered. In order to compensate for this, measures such as an increase in the amount of cooling water with respect to the stave, an increase in the number of cooling pipes, a double stave body, and the like can be considered, but this is not preferable because it complicates the stave structure and increases costs. In addition, even if such measures are taken, the cooling effect when applied to the high heat load region at the bottom of the blast furnace is not sufficient, and as the operating conditions become severe due to the long life of the blast furnace and the large amount of pulverized coal injection, The problem has become apparent.

  On the other hand, a copper (or copper alloy) stave is known as a metallurgical furnace stave. Since copper has a higher thermal conductivity than cast iron, the copper stave has the advantage that the temperature inside the main body is always kept low, but due to its high cooling capacity, especially in the high heat load region below the blast furnace, The effect is obtained. That is, even when the furnace inner refractory falls off the stave body in the high heat load region at the bottom of the blast furnace, the molten slag solidifies as soon as it comes into contact with the stave surface, and a hardly peelable solidified slag layer is generated on the stave surface. Since this hardly peelable solidified slag layer has a very low thermal conductivity, the copper stave is protected from the high heat load of the furnace, and heat removal from the furnace by the stave is appropriately suppressed.

Therefore, in order to extend the life of the blast furnace, reduce energy loss due to supercooling in the high heat load region, simplify the furnace wall structure and reduce the cost, the blast furnace stave, especially in the high heat load region of the blast furnace, It can be said that a copper stave is optimal as a stave to be applied.
Conventionally, as a copper stave used alone for a blast furnace, a type obtained by machining a rolled material or a forged material (Patent Document 1) and a type in which a cooling pipe is casted with cast copper are known. In addition, a jacket type is also known as a copper stave used in combination with a cast iron stave.
Japanese Examined Patent Publication No. 63-56283

However, these conventional copper staves have the following problems.
First, a copper stave obtained by machining a rolled material or a forged material has drawbacks such as complicated machining, high production costs, and low shape freedom. Specifically, the following problems can be mentioned, for example.

(1) The stave body needs to have a curvature according to the furnace inner diameter. However, when manufacturing staves by machining rolled materials, etc., this kind of curvature is a factor in manufacturing costs. It is extremely difficult. For this reason, the stave body must be designed in a flat plate shape, and as a result, the operating volume of the furnace is reduced.
(2) Although it is necessary to provide bosses and ribs for fixing to the iron skin on the back of the stave, these parts have to be processed and welded, which increases the cost.
(3) When the projections and grooves for holding the refractory and solidified slag are provided on the cooling operation surface inside the furnace, it is necessary to cut out from a thick plate material, which increases the manufacturing cost.

(4) When a copper stave is newly installed in an existing furnace equipped with a cast iron stave and used in combination with the existing cast iron stave, the thickness of the copper stave is made of cast iron because the profile inside the furnace must be maintained. Although it is necessary to match the thickness of the stave, in this case, the thickness of the copper stave is as high as 250 mm, and it is expensive to cut out from the rolled material or the like, and in some cases, the material cannot be obtained.
(5) When the stave is applied to the part from the hearth (cut) to the shaft, it is necessary to make the stave shape “vertical” in the vertical direction, and this requires cutting and bending. This increases the manufacturing cost.

  Furthermore, in a copper stave obtained by machining a rolled material or a forged material, the refrigerant passage inside the stave needs to be formed by drilling, and in order to form the corner portion of the refrigerant passage, the passage must be formed. It is necessary to plug weld one end of the holes after making the holes perpendicular to each other, but the corners of the passages thus provided are L-shaped, so that the refrigerant (usually cooling water) flowing through the passages There is a problem that the pressure loss increases and the energy loss is large. In addition, since the cooling water stagnates in such an L-shaped corner, deposits are likely to be formed on the inner surface of the passage of this portion, and if such deposits grow with time, it may cause pressure loss of the cooling water. Moreover, the heat transfer efficiency between the cooling water and the stave is lowered, and the cooling action by the cooling water is lowered. Furthermore, when the stagnation of the cooling water as described above occurs, bubbles are generated due to the disturbance of the cooling water flow, and these bubbles also reduce the cooling action by the cooling water. When the pressure loss as described above becomes significant, the flow rate of the cooling water is also affected, and this influence and the reduction of the cooling action also cause the function of the stave to be lowered.

Further, the cast copper stave for casting the cooling pipe has the following problems, and particularly the following problems (1) to (3) are caused. Therefore, its practical use is difficult.
(1) Since the cooling pipe and the cast part that casts the cooling pipe are not welded and are in a close contact state at most, a gap is usually formed between them. Due to the existence of this gap, the heat conduction between the cooling pipe and the casting part is not sufficient, and the casting part is likely to be damaged by the heat load from the inside of the furnace. Then, the cooling pipe exposed due to the breakage of the casting part is deformed and worn, and eventually breaks and leaks water.
(2) The cooling pipe may recrystallize due to heat during casting, which may cause the cooling pipe strength to decrease and cause damage.

(3) Since the melting point of the copper cooling pipe and the melting point of the copper casting are the same, the cooling pipe may be melted depending on the casting temperature. If the casting temperature is lowered to avoid this, gas defects are likely to occur. Moreover, when only the cooling pipe is made of iron in order to avoid such a problem, the cooling ability of the entire stave is lowered because the thermal conductivity of iron is small.
(4) In order to form the refrigerant passage inside the stave, it is necessary to bend the cooling pipe with high accuracy, and sometimes it is necessary to bend into a complicated shape, so that the manufacturing cost is high.
(5) When casting the cooling pipe, it is difficult to accurately position the pipe, and the product as designed may not be obtained. In particular, in the bent part of the cooling pipe, the curvature dimension before casting may be extended, and the dimensional accuracy may deteriorate.

In addition, even when a jacketed cast copper stave used in combination with a cast iron stave is used alone, there are the following problems.
(1) Although the amount of cooling water that can be supplied to each stave is limited due to pump capacity limitations, the jacket-type cast copper stave has a large cross-sectional area of the refrigerant passage, which inevitably reduces the cooling water flow rate. . In general, in order to withstand the heat load from the inside of the furnace, the cooling water in the refrigerant passage requires a flow rate of about 1 to 3 m / sec, but with a jacket type cast copper stave, it is less than 1 m / sec (generally 0.3 m Only a cooling water flow rate of / sec or more and less than 1 m / sec) can be obtained, and there is a risk of melting due to a heat load from the inside of the furnace.

(2) In a jacket-type cast copper stave, if a plurality of independent refrigerant passages are provided, the structure becomes complicated, and the cross-sectional area per refrigerant passage is large as described above. Only the refrigerant passage of the system level can be provided. For this reason, even when the stave is partially melted, there is a risk that the function of the refrigerant passage is completely lost. Even if water leakage from the refrigerant passage is caused by partial melting, if the cooling water supply is stopped or reduced for inspection or repair, the stave may be completely melted. It is not possible to check or even repair leaks.

(3) In the jacket structure, the coolant passage pressure loss increases because the number of turns in the refrigerant passage increases, resulting in a large energy loss. Further, it is necessary to provide a mounting boss (mounting hole) for fixing to the iron skin on the back surface of the stave, but in the jacket structure, a part of this boss protrudes to the refrigerant flow path, and this becomes a resistance of the cooling water. Therefore, it becomes a factor which produces the pressure loss of cooling water. Furthermore, since the cooling water stagnates at the corners of the jacket structure, deposits are likely to form on the inner surface of the passage of this portion, and if such deposits grow over time, the heat transfer efficiency between the cooling water and the stave decreases. Resulting in. Moreover, when the stagnation of the cooling water as described above occurs, bubbles are generated due to the disturbance of the cooling water flow, and the bubbles reduce the cooling action by the cooling water. These problems also cause the stave function to deteriorate.

  Therefore, the object of the present invention is to solve such a problem of the prior art, and can maintain an appropriate function for a long period of time even when applied to a high heat load region at the lower part of the blast furnace. An object of the present invention is to provide a metallurgical furnace stave that does not cause the problems of a conventional copper stave.

  The present inventors have been able to maintain the proper function of the copper stave applied to the high heat load region by generating a solidified slag layer on the surface of the stave even after the refractory inside the furnace is dropped. From the standpoint of being optimal as a stave applied to high heat load areas, as a result of various studies to obtain a copper stave that does not cause problems as in the above-mentioned conventional technology, a copper or copper alloy stave body is integrated. Found that a cast copper stave obtained by simultaneous casting and forming a refrigerant passage by a core at the time of casting does not cause problems as in the prior art, and can exhibit extremely superior performance exceeding expectations. It was.

The present invention has been made based on such findings, and the features thereof are as follows.
(1) The stave body is composed of a integrally cast copper or copper alloy casting , and has a coolant passage formed by a sand core during casting inside the stave body . A metallurgical furnace stave having a cross-sectional area of 2500 mm ² or less .
(2) The metallurgical furnace stave according to (1), wherein the bent portion of the refrigerant passage is provided with a curvature.
(3) A metallurgical furnace stave characterized in that, in the stave of (2), the curvature of the bent portion is at least three times the representative inner diameter of the refrigerant passage.

(4) In the stave of the above (2) or (3), the refrigerant passage is coupled or connected with a curvature through a main passage portion and a corner portion having a curvature at each end of the main passage portion. For metallurgical furnaces, characterized in that each of the inlet side passage portion and the outlet side passage portion constitutes an inlet and an outlet of the refrigerant. Stave.
(5) The metallurgical furnace characterized in that, in the stave of (4), the main passage portion of the refrigerant passage is composed of a single straight passage or two or more straight passages having a curvature at a corner portion. Stave for.
(6) A metallurgical furnace stave according to any one of the above (1) to (5) , wherein the stave body includes two or more independent refrigerant passages formed during casting.

(7) In the stave of any one of the above (1) to (6), a cross section passing through the approximate center of the stave body or the vicinity thereof, in a direction orthogonal to the axial direction of the plurality of main passage portions of the refrigerant passage. In the cross section of the stave main body, the total cross-sectional area s of the refrigerant passage and the stave main body (however, in the case where protrusions and / or grooves are formed on the front and / or back of the stave main body, the protrusions and / or grooves) Stave for metallurgical furnace, characterized in that the ratio s / S to the cross-sectional area S of the main part of the stave excluding the thickness of the part where the metal is formed is 0.05 to 0.15.

(8) A metallurgical furnace stave according to any one of the above (1) to (7), wherein protrusions and / or grooves are formed on substantially the entire cooling operation surface of the stave body.
(9) A metallurgical furnace stave according to any one of the above (1) to (8), wherein a refractory inside the furnace is fixed to a cooling operation surface of the stave body.

As described above, the metallurgical furnace stave of the present invention can maintain an appropriate function for a long period of time without causing erosion or cracking even when applied to a high heat load region at the bottom of the blast furnace, Moreover, even if the refractory inside the furnace falls off, a solidified slag layer with low peelability and low thermal conductivity is formed on the cooling operation surface due to its excellent cooling capacity, so it can properly withstand the high heat load of the furnace. and even heat extraction from the furnace can be appropriately prevented. In addition, the stave of the present invention has an advantage that it can be manufactured easily and at low cost because the stave body including the refrigerant passage is integrally manufactured by casting. In addition, since the cross-sectional area of the refrigerant passage is 2500 mm ² or less, the flow rate of the cooling water flowing in the passage can be increased, thereby obtaining a high cooling capacity capable of withstanding a high heat load from the furnace. In addition, this high cooling capacity allows the solidified slag layer to be quickly regenerated even when the solidified slag layer adhering to the cooling operation surface is peeled off due to sudden thermal shock, etc. Stave damage due to load can be prevented appropriately.

  In the inventions according to claims 2 and 3 of the present application, since the bent portion of the refrigerant passage is provided with a curvature, the pressure loss of the cooling water flowing in the passage is minimized and the appropriate flow rate of the cooling water is set. Since the cooling water does not stagnate, there is no pressure loss due to this stagnation, no decrease in cooling effect due to bubble generation, or the like.

  In the invention according to claim 4 of the present application, the refrigerant passage is coupled to the main passage portion and each end portion of the main passage portion via a corner portion having a curvature, or is coupled to the entrance side with a curvature. Since the end portion of the inlet side passage portion and the outlet side passage portion constitutes an inlet and an outlet of the refrigerant, respectively, the inside of the stave is efficiently cooled by the cooling water. It is possible to reduce the pressure loss of the cooling water flowing in the refrigerant passage to a minimum and to ensure an appropriate flow rate of the cooling water, and there is no stagnation of the cooling water. This does not cause a decrease in cooling effect due to the pressure loss or the generation of bubbles.

In the invention according to claim 6 of the present application, since there are two or more independent refrigerant passages formed at the time of casting in the stave body, the function of the refrigerant passage can be achieved even when the stave is partially melted. Is less likely to be lost, and even if water leakage from the refrigerant passage occurs due to partial melting, the supply of cooling water to some refrigerant passages is stopped or reduced. Therefore, it is possible to easily check and repair water leakage while continuing steady operation.

In the invention according to claim 7 of the present application , by setting the ratio of the cross-sectional area of the refrigerant passage in the cross section of the stave body within a predetermined range, it is possible to ensure a more appropriate cooling capacity of the stave body.

  In the invention according to claim 8 of the present application, since the protrusion and / or groove is formed on the cooling operation surface of the stave body, the solidification slag (contacted with the cooling operation surface) is formed on the cooling operation surface even when the refractory inside the furnace falls off. The solidified slag) can be reliably attached and retained, and the solidified slag layer with low thermal conductivity can appropriately withstand high heat loads and can also appropriately suppress heat removal from the furnace. .

1 to 4 show an embodiment of the stave for metallurgical furnace of the present invention, FIG. 1 is a plan view, FIG. 2 is a side view, and FIG. 3 is a cross-sectional view along III-III in FIG. FIG. 4 is a cross-sectional view showing the stave A attached to the iron skin B. FIG.
In the figure, 1 is a stave body, and 2a to 2d are refrigerant passages formed in the stave body 1. Usually, the in-furnace refractory 3 as shown by a virtual line in FIGS. 2 to 4 is fixed to the cooling operation surface a of the stave body 1 by an appropriate fixing means. This fixing means is optional, but, for example, a plurality of rod-shaped support fittings are provided on the cooling operation surface a of the stave body 1, and these support fittings are formed on each refractory brick constituting the furnace refractory 3. A structure for supporting and fixing the in-furnace refractory 3 to the stave body 1 by inserting it into the mounting hole can be adopted.

The metallurgical furnace stave of the present invention is made of a copper or copper alloy cast body in which the stave body 1 is integrally cast, and the coolant passages 2a to 2d are formed at the time of casting the stave body. It is a passage. In the stave having such a structure, the refrigerant passage 2 is simultaneously formed using a core having a small cross-sectional area when the stave body 1 is cast.
As described above, as the conventional cast copper stave, only a cast copper stave in which a cooling pipe is cast and a jacket type cast copper stave are known, and the stave body 1 is integrated as in the present invention. There is no known structure having a structure in which the coolant passage 2 is formed simultaneously with the casting of the stave body by a core having a small cross-sectional area.

  In the metallurgical furnace stave of the present invention, the number of refrigerant passages 2 formed inside the stave body 1 is arbitrary, but it is considered that the cooling function is maintained even when a part of the refrigerant passage is damaged. Two or more independent refrigerant passages are preferably formed in the stave body 1, and in this embodiment, four independent refrigerant passages 2a to 2d are formed. A refrigerant such as cooling water (hereinafter, cooling water will be described as an example) is introduced into these refrigerant passages 2 from one end side, and the cooling water cools the inside of the stave body and then the other end of the refrigerant passage. Discharged from the side.

In the refrigerant passage 2, it is preferable that all the bent portions such as corner portions have a curvature in order to reduce the pressure loss of the cooling water as much as possible and prevent the cooling water from becoming stagnation.
The refrigerant passages 2a to 2d of the present embodiment include a linear main passage portion 20 along the stave longitudinal direction or the width direction, and corner portions 23 having a predetermined curvature at each end portion of the main passage portion 20. Each of the inlet side passage portion 21 and the outlet side passage portion 22 are coupled to each other with a predetermined curvature. 4 and outlet 5 are respectively configured. A pipe (not shown) is connected to the inlet 4 and the outlet 5 by welding or the like.

  Curvature R (curvature R of the bent portion) of each corner portion 23, inlet-side passage portion 21 and outlet-side passage portion 22 itself of refrigerant passages 2a to 2d reduces the pressure loss of cooling water as much as possible. From the viewpoint of preventing stagnation, it is preferable to set it to 3 times or more of the representative inner diameter. If the curvature R is less than three times the representative inner diameter, the energy loss due to the pressure loss of the cooling water flowing through the passage becomes large, which is not preferable. In addition, if the curvature R of the bent portion is small, it becomes easy to cause stagnation of the cooling water. Therefore, deposits are likely to be formed on the inner surface of the passage of this portion. In addition, the heat transfer efficiency between the cooling water and the stave is lowered, and the cooling action by the cooling water is lowered. Furthermore, if the stagnation of the cooling water as described above occurs, bubbles are likely to be generated due to the disturbance of the cooling water flow, and these bubbles also reduce the cooling action by the cooling water. When the pressure loss as described above becomes significant, the flow rate of the cooling water is also affected, and this influence and the reduction of the cooling action also cause the function of the stave to be lowered.

The main passage portion 20 of the refrigerant passage 2 can take an appropriate form other than the linear shape as in the present embodiment, and may be, for example, curved or S-shaped, It is good also as a main channel | path part which has 2 or more linear form by giving the above curvature to a corner part.
There is no special restriction | limiting in the cross-sectional shape of channel | path 2a-2d for refrigerant | coolants, Arbitrary cross-sectional shapes, such as circular, a square, an ellipse, and a polygon, can be employ | adopted.

Moreover, in order to ensure the cooling water flow velocity in the refrigerant | coolant channel | path 2, the cross-sectional area (radial direction cross-sectional area) of the refrigerant | coolant channel | paths 2a-2d shall be 2500 mm < ² > or less (more desirably 2000 mm < ² > or less). preferable. As described above, when the cooling water flow velocity (cooling water linear velocity) in the passage is less than 1 m / sec, the cooling ability of the stave is lowered, and the stave may be melted by the heat load from the furnace. However, because of the general pumping capability for supplying cooling water to the refrigerant passage 2, if the cross-sectional area of the refrigerant passage 2 exceeds 2500 mm ² , a cooling water flow rate of 1 m / sec or more may not be ensured. .

  The stave applied to the furnace body generates a solidified slag layer having a low peelability and a low thermal conductivity on the cooling operation surface due to its cooling ability even when the furnace inner refractory 3 is dropped from the stave body 1. It is necessary to be able to withstand the high heat load from the inside of the furnace with the layer, and even when applied to the high heat load area at the bottom of the blast furnace, it is appropriate for a long period of time without causing melting or cracking. The function can be maintained. However, although the solidified slag layer generated on the cooling operation surface of the stave body 1 is hardly peelable, for example, when a sudden thermal shock is applied, peeling may occur. In such a case, it is necessary to quickly regenerate the solidified slag layer by adhering slag to the cooling operation surface of the stave body 1, and if the regeneration of this solidified slag layer is delayed, the stave body is subjected to a high heat load from the inside of the furnace. It becomes impossible to endure, and it becomes easy to cause melting and cracking.

  FIG. 6 shows the transition of the temperature inside the stave body before and after peeling and the regenerated (reattached) after the solidified slag layer peels off, when the solidified slag layer formed on the cooling operation surface of the stave body 1 peels off. ) Shows the regeneration time t. According to this, immediately after peeling of the solidified slag layer occurs, the temperature of the stave body 1 rises from about 80 ° C. to 200 ° C. at once, and the temperature gradually decreases from this temperature as the slag begins to reattach. After a certain time (regeneration time t) has elapsed, the temperature returns to a steady temperature of around 80 ° C.

  In order to prevent damage (melting damage or cracking) of the stave body due to a high heat load from the inside of the furnace when the solidified slag layer is peeled in this way, it is necessary to shorten the regeneration time t of the solidified slag layer as much as possible. Therefore, it is indispensable to maintain the flow rate of the cooling water flowing in the refrigerant passage 2 at a certain level or higher. FIG. 7 shows the relationship between the flow rate of the cooling water flowing in the refrigerant passage 2 and the regeneration time t of the solidified slag layer after separation, and when the cooling water flow rate is less than 1 m / sec, the solidified slag is shown. It can be seen that because the layer regeneration time t is too long, the stave body 1 may be damaged by a high heat load. On the other hand, when the cooling water flow rate is 1 m / sec or more, the stave body 1 is hardly damaged by a high heat load. In addition, since the effect beyond it cannot be expected even if a cooling water flow rate exceeds 4 m / sec, it is preferable that a cooling water flow rate shall be 4 m / sec or less from the surface of economical efficiency.

  Further, in order to ensure an appropriate cooling capacity of the stave body 1, it is preferable that the ratio of the cross-sectional area (total cross-sectional area) of the refrigerant passage 2 in the cross section of the stave body is within a predetermined range. That is, as shown in FIG. 8, a cross section passing through the approximate center of the stave body 1 or the vicinity thereof, and a cross section A of the stave body 1 in a direction orthogonal to the axial direction of the plurality of main passage portions 20 of the refrigerant passage 2. In -A, the ratio s / S between the total sectional area s of the refrigerant passage 2 and the sectional area S of the stave body 1 is preferably 0.05 to 0.15.

  8, protrusions and / or grooves (groove 6 in the case of FIG. 8) are formed on the front surface (cooling operation surface a) and / or the back surface (opposite surface of the cooling operation surface a) of the stave body 1. In this case, the cross-sectional area S of the stave body 1 is the cross-sectional area of the stave body part excluding the thickness x of the part where the protrusions and / or grooves are formed. Therefore, for example, when a protrusion and / or a groove is formed on the back surface (opposite surface of the cooling operation surface) of the stave body 1 as shown in FIG. The cross-sectional area of the stave body part excluding the thickness.

  If the ratio s / S is less than 0.05, the cooling ability of the stave is low, so that the stave may be melted by the heat load from the inside of the furnace. On the other hand, even if the ratio s / S exceeds 0.15, no further effect can be expected, and the strength of the stave body may be reduced.

The solidification slag as described above for the cooling operation surface a after the furnace inner refractory 3 is dropped (slag solidified in contact with the cooling operation surface a) is formed on the substantially entire surface of the cooling operation surface a of the stave body 1. Is formed, and a groove 6 is formed to hold it. The mode of formation of the groove 6 (groove depth, formation density, etc.) is arbitrary, and projections may be provided in place of or along with the groove 6.
Moreover, in this embodiment, the inside of the said groove | channel 6 is filled with the refractory 7 and the cooling operation surface side is planarized, The furnace inner refractory 2 is attached and fixed to this surface.

  In the stave of the present invention, the inner surface of the refrigerant passage 2 formed inside the stave body 1 has a relatively rough surface (cast surface) as a cast body. And the fact that the inner surface of the refrigerant passage 2 has a rough surface in this way, combined with the fact that the stave body is made of copper or copper alloy, has the following great advantages in terms of the cooling capacity of the stave. It turned out that it becomes.

  That is, the conventional stave obtained by machining a rolled material or a forged material as described above is provided with a refrigerant passage by drilling by machining, and therefore the inner surface of the refrigerant passage is rough. Small and smooth surface. By the way, when an unsteady and extremely high heat load acts on the stave (for example, when the solidified slag layer on the cooling operation surface peels off as described above), the cooling water flowing in the refrigerant passage It is preferable to take heat away from the nucleate boiling phenomenon and cool the stave body 1 quickly. The cooling water nucleate boiling phenomenon is more likely to occur when the heat transfer surface (in this case, the inner surface of the refrigerant passage) is rough.

  Therefore, the above-mentioned conventional type of the stave body in which the inner surface of the refrigerant passage has a smooth processed surface is unlikely to cause a nucleate boiling phenomenon, and therefore the stave body is likely to become hot when a high heat load is applied. The descent speed is also small. On the other hand, in the stave body of the present invention in which the inner surface of the refrigerant passage 2 has a rough casting surface, the nucleate boiling phenomenon easily occurs in the refrigerant passage, thereby instantly depriving a large amount of heat. 1 can be quickly reduced. Such a difference in action and effect is particularly noticeable when the material of the stave body is copper or a copper alloy having a high thermal conductivity. Therefore, the stave according to the present invention can machine a rolled material or a forged material. It can be said that it has an excellent cooling capacity compared to the conventional type stave obtained in this way.

When the stave body 1 is made of a copper alloy, for example, JIS
CuC1, CuC2, CuC3, etc. defined in H5100 are used. When the stave body 1 is made of a copper alloy, for example, low alloy copper such as chrome zircon copper or beryllium copper is used.
In the other drawings, reference numeral 8 denotes mounting holes formed at a plurality of positions on the back surface of the stave body 1, and the mounting holes 8 can be formed at the time of casting or by drilling after casting.
The stave A of the present invention is, for example, arranged on the inner side of the iron skin B via a refractory 9 as shown in FIG. 4 and is fixed to the iron skin B by a fixing metal fitting 10 inserted into the mounting hole 8.

  In addition, when the stave of the present invention is installed in an existing furnace equipped with a cast iron stave and is used together with the existing cast iron stave, the thickness of the stave of the present invention is reduced from the need to maintain the profile inside the furnace. It is necessary to match the thickness of the existing cast iron stave. In this case, as shown in FIG. 5, ribs 11 may be provided on the back surface of the stave body 1 so that the ribs 11 have a thickness equivalent to that of the existing cast iron stave. By adopting such a structure, the inside profile of the furnace can be maintained and so-called back wind can be prevented, and the weight of the copper or copper alloy stave and the material cost can be reduced.

The stave of the present invention is manufactured by integrally casting the stave body 1 using copper or a copper alloy as a raw material, and simultaneously forming the refrigerant passage 2 by the core at the time of casting. The sand core is used.
Further, the stave of the present invention has a relatively small cross-sectional area of the refrigerant passage 2 in order to increase the flow rate of the cooling water, so that when the heat is partially concentrated on the sand core during casting, the shape of the sand core is changed. In the conventional manufacturing method using core sand (sand mainly composed of SiO ₂ ), it is almost impossible to reliably form the refrigerant passage 2 having a small cross-sectional area. .

In order to reliably form the refrigerant passage 2 having a small cross-sectional area, it is necessary to use a sand core having a high thermal conductivity, a large heat capacity, and a fire resistance. It becomes possible. As such core sand, thermal conductivity: 0.5 to 1.5 kcal / m · hr · ° C., fire resistance Zeger cone (SK): 17 to 37, thermal expansion coefficient (500 ° C.): 0.5 to It is preferable to use sand (so-called zircon sand) mainly composed of ZrO ₂ having physical properties of 1.5% and a melting point of about 1750 to 2000 ° C. In addition, as a casting method, it is preferable to perform casting while inserting a metal pipe into the core sand and blowing a coolant such as air into the pipe to cool the core. And, by adopting a combination of such a special material sand core and the above-mentioned special casting method, the present invention has a refrigerant passage having a small cross-sectional area of 2500 mm ² or less. Stave can be manufactured.

The metallurgical furnace stave of the present invention as described above has the following advantages over the conventional copper stave.
(1) Even when it is applied to the high heat load area at the bottom of the blast furnace, it can maintain proper functions for a long time without causing melting or cracking, and even if the refractory 3 inside the furnace falls off Because of its excellent cooling capacity, a solidified slag layer with low peelability and low thermal conductivity is formed on the cooling operation surface, so it can withstand high heat loads from the furnace and appropriately suppresses heat removal from the furnace. Is done.

(2) Since the inner surface of the refrigerant passage 2 formed inside the stave body 1 has a relatively rough surface (cast surface) as a cast body, a high heat load is applied unsteadily. However, the nucleate boiling phenomenon easily occurs in the refrigerant passage, thereby instantly depriving a large amount of heat, the temperature of the stave body 1 can be quickly reduced, and the stave body material is made of copper having high thermal conductivity. In combination with the copper alloy, an excellent cooling effect can be exhibited.

(3) Since the stave body 1 is composed of a cast body that is integrally cast, and the refrigerant passage 2 therein is also formed when the stave body is cast, a conventional rolled material or forged material is machined. The shape and structure of the main body 1 of the stave body 1 does not need to be complicated as in the obtained copper stave, and does not cause a problem in manufacturing cost unlike the stave obtained by machining because it is a cast body. Can be selected arbitrarily. In addition, an arbitrary curvature R can be given to a bent portion such as the corner portion 23 of the refrigerant passage 2, and the pressure loss of the cooling water flowing through the refrigerant passage 2 can be appropriately prevented. It is also possible to prevent stagnation of cooling water.

(4) Since the coolant passage 2 is directly formed inside the stave body 1 by casting, it is caused by a problem such as a conventional cast copper stave for casting the cooling pipe, that is, a gap between the cooling pipe and the casting part. Damage to the casting or cooling pipe, ensuring processing accuracy when bending the cooling pipe, deterioration of dimensional accuracy due to elongation of the bending part of the casting, deterioration of cooling pipe strength due to heat during casting, erosion, etc. There is no fear of causing any problems.

(5) Since the refrigerant passage 2 is configured to have a small cross-sectional area by casting the stave body 1, the cooling water flow rate in the refrigerant passage 2 is increased as compared with the conventional jacketed cast copper stave (cooling water flow velocity). 1 m / s or more), and a high cooling capacity capable of withstanding a high heat load from the inside of the furnace is obtained. In addition, this high cooling capacity enables the solidified slag layer to be quickly regenerated even when the solidified slag layer adhering to the cooling operation surface is peeled off due to sudden thermal shock, etc. Stave damage due to load can be prevented appropriately.

  Similarly, since the refrigerant passage 2 is configured to have a small cross-sectional area by casting the stave body 1, independent multi-system refrigerant passages can be provided, and the function of the refrigerant passage 2 can be achieved even when the stave is partially melted. The cooling water is supplied to some of the refrigerant passages 2 even when water leaks from the refrigerant passages 2 due to partial melting of the stave. By stopping or reducing the above, it is possible to easily perform inspection / repair such as water leakage while continuing normal operation.

(6) Also, instead of a complicated refrigerant passage having many turns like the conventional jacketed cast copper stave, a straight refrigerant passage 2 can be formed, and an iron skin is attached in the middle of the passage. Since there is no part of the boss for overhanging, the pressure loss of the cooling water is small.
As described above, the metallurgical furnace stave of the present invention has an excellent function, and therefore, in the molten slag existing area (usually the morning glory part of the blast furnace, the upright part, the lower part of the shaft), which is the highest heat load area in the blast furnace. It is particularly suitable as a stave to be applied.
Moreover, the metallurgical furnace stave of the present invention can be applied to shaft metallurgical furnaces other than blast furnaces such as scrap melting furnaces, and various metallurgical furnaces such as smelting reduction furnaces and electric furnaces.

The top view which shows one Embodiment of the stave for metallurgical furnaces of this invention Side view of metallurgical furnace stave shown in FIG. Sectional drawing which follows the III-III line in FIG. Sectional view showing the metallurgical furnace stave shown in FIG. 1 attached to the furnace shell Sectional drawing which shows other embodiment of the stave for metallurgical furnaces of this invention, and shows the state which attached the stave to the iron skin of the furnace When the solidified slag layer generated on the cooling operation surface of the stave body has peeled off, the transition of the temperature inside the stave body before and after peeling, and the regeneration until the solidified slag layer is regenerated (reattached) after peeling. Graph showing time t The graph which shows the relationship between the regeneration time t of the solidification slag layer after producing | generating peeling of the cooling water flow rate which flows in the channel | path for refrigerant | coolants Explanatory drawing which shows the cross section AA of the stave main body in the cross section which passes along the approximate center of a stave main body, or its vicinity, and is orthogonal to the axial direction of the several main channel | path part of the refrigerant | coolant channel | paths.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stave body 2, 2a-2d Refrigerant passage 3 Furnace inside refractory 4 Inlet 5 Outlet 6 Groove 7 Refractory 8 Mounting hole 9 Refractory 20 Main passage part 21 Inlet side passage part 22 Outlet side passage part 23 Corner part 10 Fixed Bracket 11 Rib A Stave B Iron skin a Cooling operation surface

Claims (9)

The stave body is composed of a cast body made of copper or copper alloy integrally cast , and has a refrigerant passage formed by a sand core at the time of casting inside the stave body , and the cross-sectional area of the refrigerant passage is A metallurgical furnace stave having a thickness of 2500 mm ² or less .   The metallurgical furnace stave according to claim 1, wherein the bent portion of the refrigerant passage is provided with a curvature.   The metallurgical furnace stave according to claim 2, wherein the curvature of the bent portion is three times or more the representative inner diameter of the refrigerant passage.   The refrigerant passage is composed of a main passage portion, and an inlet-side passage portion and an outlet-side passage portion that are coupled to each end of the main passage portion through a corner portion having a curvature or are coupled with a curvature. The metallurgical furnace stave according to claim 2 or 3, wherein the end portions of the inlet side passage portion and the outlet side passage portion respectively constitute an inlet and an outlet of the refrigerant. 5. The metallurgical furnace stave according to claim 4, wherein the main passage portion of the refrigerant passage is composed of a single straight passage or two or more straight passages having a curvature at a corner portion. The metallurgical furnace stave according to claim 1, 2, 3 , 4 or 5 , wherein the stave body has two or more independent refrigerant passages formed during casting.   The cross section passing through substantially the center of the stave main body or the vicinity thereof, and in the cross section of the stave main body in the direction perpendicular to the axial direction of the plurality of main passage portions of the refrigerant passage, the total cross sectional area s of the refrigerant passage and the stave main body (However, if protrusions and / or grooves are formed on the front and / or back of the stave body, the cross-sectional area S of the stave body excluding the thickness of the portion where the protrusions and / or grooves are formed) The metallurgical furnace stave according to claim 1, wherein the ratio s / S of the metallurgical furnace is 0.05 to 0.15.   8. The metallurgical furnace stave according to claim 1, wherein a protrusion and / or a groove is formed on substantially the entire cooling operation surface of the stave body.   The metallurgical furnace stave according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein a refractory inside the furnace is fixed to a cooling operation surface of the stave body.

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