JPWO2018037957A1 - Stove for furnace body protection - Google Patents

Abstract

Provided as a furnace body protection stave installed on the inner wall of a furnace such as a blast furnace, which can reduce the probability of water leakage of cooling water and prevent breakage of the stave to achieve long life The purpose is to Such a furnace body protection stave incorporates a steel pipe 3 in a groove 2 provided on the furnace outer surface 1 a or the furnace inner surface 1 b of the copper stave main body 1, and Are joined with the brazing filler metal 4 to form a water passage for stave main body cooling in the stave main body 1.

Description

  The present invention relates to a furnace body protection stave used to protect a furnace wall such as a blast furnace exposed to high temperatures.

  Conventionally, a furnace cooling device (hereinafter referred to as a stave) has been used to protect a blast furnace body from heat load in the furnace. The stave for protecting the furnace body is made of cast iron, rolled copper, cast copper or the like, and has a water passage for cooling in the stave main body. In recent years, in order to cope with the high heat load of the blast furnace body, a stave with a higher cooling capacity is required, and as a result, the adoption of a stave made of copper having a high thermal conductivity is increasing.

  In such a furnace body protection stave, the cooling water channel formed in the stave body differs depending on the design concept and which material is used. That is, depending on the material, it is general to cast a steel pipe with cast iron in cast iron, form a water channel by machining (drilled hole) in rolled copper, and form a water channel by casting in cast copper.

  Hereafter, it is made of rolled copper, which has a relatively large number of adopted because the dimensional accuracy of the water channel is good because it is manufactured by machining, and there is almost no concern about defects such as "nests" generated during casting. The furnace body protection stave will be described.

  FIGS. 7 (a) and 7 (b) are respectively a front view showing a configuration of an example of a conventional furnace body protection stave made of rolled copper and a cross-sectional view taken along the line A-A. In the example shown in FIGS. 7A and 7B, the stave main body 51 made of rolled copper is provided with a plurality of water passages 52 (three in this case). Each water channel 52 is formed in the stave main body 51 by machining (drilling). The water passage 52 is a water passage 52 b-1, 52 b-2 which is perpendicular to the water passage 52 a penetrating through the stave main body 51 in the longitudinal direction and the water passage 52 a for communicating with the piping 53-1 53-2. And consists of Both ends of the water channel main body 52a are sealed by welding sealing members 54-1 and 54-2. In the water supply and drainage passages 52b-1 and 52b-2, water supply and drainage pipes 53-1 and 53-2 made of steel pipes or copper pipes are fixed by welding. The stave main body 51 is provided with a plurality of (in this case, four) bolts 55.

  As an example is shown in FIG. 8, the furnace body protecting stave having the above-described configuration is fixed to the iron shell 61 of the blast furnace furnace body by screwing using bolts 55 and nuts 56. The pipes 53-1 and 53-2 for water supply and drainage of the stave main body 51 penetrate holes formed in the iron shell 61 of the blast furnace body, and are supplied with water and drained from the outside of the furnace body.

  If the copper stave is damaged by repeated heat loads in the blast furnace, the main cause is water leakage from the cooling system. In recent years, the thermal load on the furnace body has increased remarkably due to the increase of the pulverized coal injection, and stave failure has occurred earlier than the expected life expected at the design stage. Submersion in the furnace resulting from such stave breakage greatly hinders stable operation of the blast furnace. Therefore, if a water leak is identified during operation, stop measures should be taken for cooling water circulated through the stave water channel. By stopping the cooling water, the copper stave is exposed to the high temperature in the furnace and the environment of wear due to the raw material, so the stave itself disappears in a short period of time. With the disappearance of the copper stave (loss of the cooling function), the blast furnace main body shell is now directly exposed to high temperatures, causing iron skin cracking and thermal deformation, making it difficult to continue the blast furnace operation itself.

Although the water leak of the copper stave is discovered by the mixture of the gas in the blast furnace in the cooling water, it is presumed from the survey results that the water leak is occurring.
(1) Water leakage due to the occurrence of cracks in the weld joint between the water supply and drainage water channel of the stave body and the water supply and drainage piping due to deformation due to high heat load,
(2) Water leakage due to generation of cracks in welds of sealing members used to close unnecessary openings when the water channel is formed by machining the stave main body by deformation due to high heat load;
(3) Water leakage due to holes in the cooling water channel due to abrasion by materials in the furnace due to low mechanical strength and hardness.
Therefore, for long-term stable operation of the blast furnace, it is necessary to solve the water leak of the copper stave and to extend the life.

  In the case of a rolled copper stave, a cooling water passage is formed in the stave main body itself, so the cooling ability is higher than water cooling of cast-in piping employed in cast iron staves and the like. However, in the case of a rolled copper stave, damage to the cooling water channel due to damage to the stave main body often results in premature disappearance of the stave main body. Therefore, the rolled copper stave has a short life as a result. On the other hand, in the cast iron stave, the cooling passage is constituted by a cast pipe and is independent of the stave main body. Therefore, although damage to the cooling passage is small due to damage to the stave main body, the cooling capacity is not high because the heat transfer coefficient is lowered due to the boundary layer formed between the piping and the stave main body in cast piping.

  To solve the above problems and extend the life of the copper stave, dig a groove on the outside of the copper stave by machining etc., incorporate a steel pipe into the groove, and fix a steel plate with a bolt Structure is known (Patent Document 1).

Japanese Patent Application Laid-Open No. 2002-146418

However, the copper stave of the structure disclosed in Patent Document 1 has the following drawbacks. That is, since the connection between the copper stave and the steel plate for fixing the pipe in the groove is by a bolt, the end of the steel pipe can not be connected. Therefore, due to the difference in thermal expansion coefficient between the copper stave and the steel plate (copper: about 1.6 × 10 ⁻⁵ / ° C., iron: about 1.0 × 10 ⁻⁵ / ° C.), the steel plate is deformed by heat load, The mouth of the steel plate opens. Then, the raw material intrudes here, the heat load increases, and finally, bolt breakage or the like occurs. As a result, the steel plate is detached from the copper stave, and the function of the stave is lost simultaneously with the holding function of the pipe. The cost can be reduced by using a steel plate outside the furnace, but at the same time, the cooling capacity of the blast furnace furnace shell and the refractory also decreases.

  SUMMARY OF THE INVENTION An object of the present invention is a stave installed on the inner wall of a furnace such as a blast furnace, which can reduce the probability of water leakage of cooling water and prevent breakage of the stave to achieve a long life of the furnace. To provide.

  As a result of solving the above-mentioned problems of the prior art and earnestly researching to realize the above object, the inventors have developed a novel furnace body protecting stave described below. That is, according to the present invention, a steel pipe is incorporated in a groove provided on the furnace outer surface or the furnace inner surface of a copper stave main body, and the groove of the stave main body and the pipe are joined with a brazing filler metal. A furnace body protecting stave having a structure in which a water passage for stave main body cooling is formed.

In the furnace body protecting stave according to the present invention configured as described above,
(1) forming a lid in the groove so as to cover the brazing material by welding;
(2) A pipe inlet and a pipe outlet projecting from the furnace outer surface of the stave main body are integrally formed with the pipe when the pipe is incorporated into the groove at one end and the other end of the pipe. ,
(3) A protective pipe is provided on the outer periphery of each of the pipe inlet and the pipe outlet,
(4) providing a first intermediate member between the surface of the groove and the brazing material;
(5) providing a second intermediate member between the brazing material and the outer surface of the pipe;
Is considered to be a more preferable solution.

  According to the furnace body protection stave of the present invention, for example, a water passage for cooling a copper stave main body such as rolled copper is constituted by steel piping, and a high thermal load is achieved by joining and embedding the copper stave main body and piping with a brazing filler metal. It is possible to obtain a stave with a long life. Further, even if the stave main body is deformed, the welded portion is not in direct contact with the water channel, so there is no concern of water leakage from the welded portion conventionally used in each portion of the water channel. Furthermore, by filling the gap between the stave main body and the cooling pipe with a brazing filler metal, the cooling capacity for the stave main body can be increased.

(A) to (d) are a front view, a rear view, a sectional view taken along the line A-A, and a sectional view taken along the line B-B, respectively, showing the configuration of an example of the furnace body protecting stave of the present invention It is. (A) to (d) are a front view, a rear view, a cross-sectional view along the line A-A and a line B-B, respectively, showing the configuration of another example of the furnace body protecting stave of the present invention FIG. (A) to (c) are each taken along the line A-A in FIGS. 1 (a) and 1 (b) for explaining each step in the method of manufacturing an example of the furnace body protecting stave of the present invention. FIG. (A) to (c) respectively show lines AA in FIGS. 2 (a) and 2 (b) for explaining each step in the method for manufacturing another example of the furnace body protecting stave of the present invention. FIG. (A) and (b) respectively show the configuration of still another example of the furnace body protecting stave according to the present invention as a sectional view taken along the line B-B in FIG. 1 (a) and (b) and FIG. It is a figure shown as a sectional view which met the BB line of a) and (b). (A), (b) is a figure which shows the structure of the further another example of the stave for furnace body protection of this invention as sectional drawing along the BB line of FIG. 1 (a), (b), respectively. is there. (A), (b) is a front view showing a configuration of an example of a conventional furnace body protection stave made of rolled copper and a cross-sectional view taken along the line A-A. It is a figure for demonstrating an example which mounts the stave for furnace body protection of this invention to the furnace body of a blast furnace.

  1 (a) to 1 (d) are respectively a front view and a rear view showing a configuration of an example of a furnace body protecting stave according to the present invention, a sectional view along line A-A and a line B-B. FIG. In an example of the furnace body protecting stave according to the present invention shown in FIGS. 1 (a) to 1 (d), as shown in FIGS. 1 (a) and 1 (b), it was formed on the furnace outside surface 1a of the stave main body 1 made of copper. As shown in FIGS. 1 (c) and 1 (d), the steel pipe 3 is incorporated in the groove 2 (3 in this case), and the groove 2 of the stave main body 1 and the pipe 3 are joined with the brazing material 4 Thus, the stave main body 1 has a structure in which a water path for cooling the stave main body is formed.

  Further, in another example of the furnace body protecting stave according to the present invention shown in FIGS. 2 (a) to 2 (d), as shown in FIGS. 2 (a) and 2 (b), the furnace inside of the stave main body 1 made of copper. Grooves 2 (three in this case) are provided on the surface 1b, and further, outlet holes 7-1 and 7-2 for piping are provided on the furnace outer surface 1a, as shown in FIGS. 2 (c) and 2 (d). It is also possible to incorporate a steel pipe 3 and join the groove 2 of the stave main body 1 and the pipe 3 with a brazing filler metal 4 to form a stave main body cooling channel formed of the pipe 3 in the stave main body 1 It is possible.

  FIGS. 3 (a) to 3 (c) are each a line AA of FIGS. 1 (a) and 1 (b) for explaining each step in the method of manufacturing an example of the furnace body protecting stave of the present invention. FIG. A method of manufacturing an example of a furnace body protecting stave according to the present invention will be described according to FIGS. 3 (a) to 3 (c). First, as shown in FIG. 3 (a), copper made of grooves 2 formed in the furnace outer surface 1a The stave main body 1 and the steel pipe 3 are prepared. The groove 2 can be formed by machining on the furnace outer surface 1 a of the stave main body 1 made of copper using an end mill or the like. The cross-sectional shape of the groove 2 may be a U-shape, but it may be any shape as long as the pipe 3 can be incorporated. When the pipe 3 is incorporated into the groove 2 at one end and the other end of the pipe 3, the pipe 3 made of steel has a pipe inlet portion 3-1 and a pipe outlet portion 3-3 projecting from the furnace outer surface 1 a of the stave main body 1. And 2 are integrally formed with the pipe 3. The pipe inlet portion 3-1 and the pipe outlet portion 3-2 can be formed by bending at both ends of one pipe 3 using a bender or the like. In addition, a protective pipe (not shown) can also be provided in the piping inlet-port part 3-1 and the piping outlet-port part 3-2 around those.

  Next, as shown in FIG. 3 (b), the pipe 3 is incorporated in the groove 2 so that the pipe inlet 3-1 and the pipe outlet 3-2 protrude from the furnace outer surface 1a. Then, as shown in FIG. 3 (c), between the groove 2 of the stave main body 1 and the pipe 3, the brazing material 4 heated to a predetermined temperature and melted is poured, and then cooled and hardened. The brazing material 4 is hardened. Thus, as the furnace body protection stave of the present invention, the groove 2 of the stave main body 1 and the pipe 3 are joined with the brazing filler metal 4 to form a water passage composed of the stave main body cooling pipe 3 in the stave main body 1 You can get the structure.

  Further, as another example, FIGS. 4 (a) to 4 (c) are diagrams for explaining respective steps in a method of manufacturing another example of the furnace body protecting stave of the present invention, as shown in FIGS. It is a figure along the AA of (b). A manufacturing method of another example of the furnace body protecting stave of the present invention will be described according to FIGS. 4 (a) to 4 (c). First, as shown in FIG. 4 (a), the groove 2 is formed on the furnace inner surface 1b. Copper stave main body 1 and steel in which outlet holes 7-1 and 7-2 are formed on the furnace outer surface 1a for making the pipe inlet port 3-1 and the pipe outlet port 3-2 project from the furnace outer surface 1a Prepare made of piping 3. The groove 2 can be formed by machining the inner surface 1b of the stave main body 1 made of copper using an end mill or the like. The outlet holes 7-1 and 7-2 can be formed by machining from the bottom of the groove 2 or the furnace outer surface 1a using a drill or the like.

  Next, as shown in FIG. 4B, the groove 3 is provided with the pipe 3 and the pipe inlet 3-1 and the pipe outlet 3-2 are connected to the furnace outer surface through the outlet holes 7-1 and 7-2. Incorporate it to project from 1a. Then, as shown in FIG. 4C, the brazing material 4 heated to a predetermined temperature and melted is poured between the groove 2 of the stave main body 1 and the pipe 3 and then cooled. Hard solder 4 is hardened. Thus, as the furnace body protection stave of the present invention, the groove 2 of the stave main body 1 and the pipe 3 are joined with the brazing filler metal 4 to form a water passage composed of the stave main body cooling pipe 3 in the stave main body 1 You can get the structure.

  In the furnace body protecting stave according to the present invention, the groove 2 is dug in a U-shape by machining or the like on the furnace outer surface 1a or the furnace inner surface 1b of the stave main body 1 made of copper such as rolled copper. The steel pipe 3 is incorporated into the V-shaped groove 2. By using copper having a thermal conductivity higher than that of cast iron as the stave main body 1 and making the cooling water channel independent with the steel pipe 3, damage to the stave main body 1 or stave main body 1 caused by breakage of the cooling water channel as described above. It is possible to prevent the early disappearance of The U-shaped groove 2 processed on the furnace outer surface 1 a or the furnace inner surface 1 b of the stave main body 1 made of copper serves as a cooling water passage of the stave main body 1. The steel pipe 3 is formed in advance into a predetermined shape (a shape corresponding to the layout of the U-shaped groove 2), and is incorporated into the U-shaped groove 2 of the cross section of the copper stave main body 1. In a state where the pipe 3 is incorporated, the stave main body 1 and the pipe 3 are joined by the brazing material 4.

  As for the temperature to which the stave main body 1 made of copper is exposed in the actual machine, the present inventors measured the temperature in the actual machine (during blast furnace operation) while flowing water through the cooling channel for a long time (10 seconds pitch data for 2 years) It was implemented, and it was found that the stave main body rose only up to about 400 ° C. From this, when the stave main body 1 and the pipe 3 are joined by a brazing filler metal (such as BAg specified in JIS Z 3261) whose melting temperature is defined as 450 ° C. or more, the copper stave main body 1 and the pipe The present invention has been completed with the expectation that there will not be any difference with 3. If the temperature of the stave main body 1 becomes 400 ° C. or higher, only the state where the cooling water is stopped can be considered, and if it is in this state, the copper 3 is made before the piping 3 is detached from the copper stave main body 1 It is considered that the stave main body 1 itself disappears due to the heat load in the furnace and the wear due to the raw material. In addition, since the stave main body may be deformed at the time of joining if the melting temperature of the brazing material is too high, the melting temperature of the brazing material is preferably 450 ° C. or more and 1083 ° C. or less.

  In the furnace body protecting stave according to the present invention described above, a failure to hold the pipe occurs due to detachment of the copper stave main body and the steel plate, which becomes a problem in Patent Document 1 disclosing the method of holding the pipe by bolt fastening of the steel plate. Therefore, further extension of the life of the stave main body 1 can be expected. In addition, although a gap is generated between the U-shaped groove 2 and the pipe 3, an alloy for “hard brazing” is poured into the gap to closely bond the stave main body 1 and the pipe 3. The heat transfer coefficient between the stave main body 1 and the pipe 3 can be increased, and the cooling capacity of the stave main body 1 by the water channel constituted by the pipe 3 is enhanced. Also, in general, if the pipe 3 is welded, a heat affected zone is locally formed, and the heat load during use causes a crack in the pipe 3 to cause water leakage, but the characteristics of the hard brazing As it can be joined without melting the base material, there is no cracking due to local heat affected zone. Since the temperature is raised to around the transformation point (about 750 ° C.) of the steel pipe 3 during brazing, it is neither melting nor local, so there is no cracking due to the heat-affected zone. In addition, the brazing filler metal absorbs the difference in the amount of thermal expansion between the copper of the stave main body and the steel of the pipe, and also has the effect of reducing the stress concentration.

  Furthermore, with the above-described structure, it is possible to eliminate the welded joint between the water inlet / outlet and the inlet / outlet and the pipe, which has conventionally been a weak point of the rolled copper stave due to water leakage. In addition, the cooling piping is made of steel with higher temperature hardness than copper, and by making it independent from the copper stave main body such as rolled copper, holes in the cooling path due to thermal deformation and wear of the copper stave main body and water leakage occur You can lower the probability. As a result, the cooling capacity of the copper stave of the present invention is higher than that of the conventional cast iron stave, and the breakage of the cooling channel is less than that of the conventional copper stave. Therefore, it is possible to construct a furnace body protecting stave which achieves a long life.

  5 (a) and 5 (b) are cross-sectional views taken along the line B-B of FIG. 1 (a) and FIG. 2 (a) respectively showing the configuration of still another preferred embodiment of the furnace body protecting stave of the present invention. And FIG. 7B is a cross-sectional view taken along the line B-B of FIG. In the preferred embodiment shown in FIG. 5 (a) in which the groove 2 is provided in the furnace outer surface 1a of the stave main body 1, after the stave main body 1 and the pipe 3 made of copper are joined by the brazing material 4, further detachment prevention is For this purpose, the lid 5 is welded to the U-shaped groove 2 and the end of the lid 5 and the end of the groove 2 of the stave main body 1 are joined by welding 6 and attached. Further, as in the preferred example shown in FIG. 5 (b), also in the case where the groove 2 is provided on the furnace inner surface 1 b of the stave main body 1, the lid 5 can be similarly joined at the welding portion 6. The material of the lid 5 is preferably made of the same copper as the stave main body, but lids of other materials can also be used.

  6 (a) and 6 (b) are diagrams showing the configuration of still another preferred example of the furnace body protecting stave according to the present invention as a cross-sectional view taken along the line B-B in FIG. 1 (a). . In the example shown in FIG. 6A, the first intermediate member 6-1 is provided between the surface of the groove 2 and the brazing material 4. Further, in the example shown in FIG. 6 (b), the second intermediate member 6-2 is provided between the brazing material 4 and the outer surface of the pipe 3. As the first intermediate member 6-1 and the second intermediate member 6-2, a material having an appropriate thermal conductivity may be used according to the design level of the cooling capacity of the stave. After incorporating the intermediate member 6-1 or the second intermediate member 6-2, it is possible to join with a brazing filler metal. By adjusting the thermal conductivity and thickness of the intermediate member, it is possible to adjust the cooling capacity of the stave to meet the purpose. In order to adjust the thermal conductivity of the entire stave and exert the effect of adjusting the cooling capacity, a member having a thermal conductivity different from at least one of the stave main body 1, the pipe 3 and the brazing material 4 is used as an intermediate member. It may be used. Further, it is also possible to change the function of the stave other than the thermal conductivity by adjusting the physical properties other than the thermal conductivity of the intermediate member. In the preferred example of FIGS. 6A and 6B, although the groove 2 is formed on the furnace outer surface 1a, the first intermediate member is also used in the example in which the groove 2 is formed on the furnace inner surface 1b. It goes without saying that the effect of 6-1 or the second intermediate member 6-2 can be obtained.

  In the furnace body protection stave according to the present invention, the copper stave main body is formed by a steel pipe, and the copper stave main body and the pipe are joined and embedded with a hard brazing material to withstand high heat load and long life. This is an effective method for protecting the inside of the furnace wall exposed to high temperatures also in blast furnaces and other heating furnaces because it is possible to obtain a stabilized furnace body protection stave.

DESCRIPTION OF SYMBOLS 1 stave main body 1a furnace outer surface 1b furnace inner surface 2 groove 3 piping 3-1 piping inlet part 3-2 piping outlet part 4 brazing filler metal 5 lid 6-1 first intermediate member 6-2 second intermediate member 7 -1, 7-2 exit hole

Claims (6)

  Install a steel pipe into the groove on the furnace outer surface or furnace inner surface of the copper stave main body, join the groove of the stave main body and the pipe with a brazing filler metal, and connect the stave main body to the stave main body A furnace body protecting stave characterized by having a structure formed by:   The furnace body protecting stave according to claim 1, wherein a lid is formed in the groove so as to cover the brazing material by welding.   At one end and the other end of the pipe, when the pipe is incorporated into the groove, a pipe inlet and a pipe outlet projecting from the furnace outer surface of the stave main body are integrally formed with the pipe. The stave for furnace body protection according to claim 1 or 2.   4. A furnace body protecting stave according to claim 3, wherein protective pipes are provided on outer peripheries of the pipe inlet and the pipe outlet.   The furnace body protecting stave according to any one of claims 1 to 4, wherein a first intermediate member is provided between the surface of the groove and the brazing material. The furnace body protecting stave according to any one of claims 1 to 5, wherein a second intermediate member is provided between the brazing material and the outer surface of the pipe.

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