Annealing furnace, construction method of annealing furnace, and prefabricated structure

Abstract

Provided are: an annealing furnace which can be constructed by applying a prefabrication method even in the case where the furnace is large in length; a method for constructing said annealing furnace; and a prefabricated structure. This annealing furnace is equipped with a case and multiple rows of rollers for conveying steel strips to the top and bottom of the interior of the case, and is characterized by having: multiple horizontal division surfaces that divide a furnace body in the horizontal direction; and vertical division surfaces that divide the respective strips horizontally divided by the horizontal division surfaces further in a direction perpendicular to the longitudinal direction of the furnace body.

Description

[Technical field]

[0001] The present invention relates to an annealing furnace, an annealing furnace construction method, and a prefabricated structure. [Background technology]

[0002] A conceptual diagram of an example of a galvanizing line equipped with an annealing furnace is shown in Figure 1. The illustrated annealing furnace 100A is equipped with a heating chamber 92 for heating a steel strip 91 to a predetermined temperature, a heat-soaking chamber 94 for keeping the heated steel strip at a constant temperature, and cooling chambers 96, 96 for cooling the soaked steel strip to a predetermined temperature, and further equipped with a galvanizing tank 98.

[0003] The steel strip 91 continuously passes between a top roll 93a provided near the upper surface inside the annealing furnace and a bottom roll 93b provided near the lower surface, and is transported through the annealing furnace while being heated, soaked, and further cooled.

[0004] In the embodiment shown in Fig. 1, the heating chamber 92, the soaking chamber 94, and the cooling chamber 96 are separate bodies that form an annealing furnace, but these chambers may be integrally formed depending on the construction site. The total length of the facility including the annealing furnace equipped with the heating chamber 92, the soaking chamber 94, and the cooling chamber 96 is 30 to 50 m, but the total length of the annealing furnace equipped with the heating chamber 92 or the annealing furnace equipped with the heating chamber 92 and the soaking chamber 94 is 10 to 25 m. When constructing these various types of annealing furnaces, a panel construction method has been conventionally adopted.

[0005] 2 shows a perspective view of an annealing furnace 100B equipped with a heating chamber 92. In the panel construction method, a top roll chamber 95a in which a top roll 93a is arranged, a bottom roll chamber 95b in which a bottom roll 93b is arranged, an end panel 97, and a shell panel 98 are each manufactured in a manufacturing factory, and then transported to a construction site for assembly. Specifically, the bottom roll chamber 95b is attached to the support 99, the end panel 97 is attached on top of the bottom roll chamber 95b, and the top roll chamber 95a is placed on the end panel 97. Once the framework of the furnace body is complete in this way, the furnace shell panels 98 are attached in sequence. After that, the joints are welded to form the furnace shell. Next, a heat insulating material is laid from the inside, and the bottom roll 93b, the top roll 93a, and the heater 93c are attached.

[0006] However, in the above panel construction method, the installation work at the construction site requires a lot of labor and time, and there is a demand for a method that is easier and can be constructed in a shorter time. As such a method, Patent Document 1 proposes a prefabricated construction method (block construction method).

[0007] In the prefabricated construction method of Patent Document 1, the furnace body is cut horizontally into blocks, which are then fabricated in a factory and transported to the construction site where they are stacked to construct the heating furnace. This significantly reduces the amount of work at the construction site and makes it possible to shorten the construction period. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2002-194427 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, in the prefabricated construction method of Patent Document 1, when the construction site is inland, each block needs to be transported by trailer from the factory to the construction site. The length of each block is limited to the length that can be transported by trailer. For this reason, the prefabricated construction method of Patent Document 1 has a problem that it cannot be used for annealing furnaces with long furnace lengths. In particular, some annealing furnaces, in which the heating zone and soaking zone are integrated, are over 20 meters long. There was also a demand to renovate and rebuild only the upper part while leaving the bottom roll chamber intact, but there was a problem that the conventional prefabricated construction method could not be used for annealing furnaces with long furnace lengths. Therefore, an object of the present invention is to provide an annealing furnace to which prefabricated construction methods can be applied even in the case of an annealing furnace with a long furnace length, a construction method for the annealing furnace, and a prefabricated structure constituting the annealing furnace. [Means for solving the problem]

[0010] As a result of extensive research aimed at solving the above problems, the present inventors have discovered the following. By dividing the annealing furnace both horizontally and vertically, the prefabricated construction method can be applied to annealing furnaces with long furnace lengths. If the annealing furnace is simply divided vertically, the resulting annealing furnace will be structurally weak and may not be able to support its own weight. Even if it can support it, it may not have sufficient earthquake resistance. The inside of the annealing furnace is an atmosphere of hydrogen and nitrogen, and needs to be isolated from the outside air. If the annealing furnace is simply divided vertically, a cross-shaped joint will be created, which may cause a problem in that it is difficult to ensure sealing at the cross-shaped joint. In a preferred embodiment of the present invention, the annealing furnace is not simply divided vertically, but the vertical division positions are appropriately adjusted with respect to each horizontal division plane, thereby making it possible to solve the above-mentioned further problem.

[0011] Based on the above, the present inventors have completed the following invention. The first aspect of the present invention is an annealing furnace having a housing and a plurality of rows of rolls for transporting a steel strip at the top and bottom inside the housing, The annealing furnace is characterized in that the annealing furnace has a horizontal dividing surface that divides the furnace body in the horizontal direction, and the horizontal dividing bands divided by the horizontal dividing surface further have vertical dividing surfaces that divide each of the horizontal dividing bands in a direction perpendicular to the longitudinal direction of the furnace body.

[0012] In the first aspect of the present invention, it is preferable that the annealing furnace has a plurality of horizontally divided surfaces, and the position of at least one of the vertically divided surfaces in the longitudinal direction of the furnace body does not coincide with the position of the vertically divided surfaces in the longitudinal direction of the furnace body in the adjacent horizontally divided bands.

[0013] In the first aspect of the present invention, it is preferable that the positions in the longitudinal direction of the furnace body of the vertical dividing surfaces in the horizontal dividing bands adjacent to each other in the vertical direction are spaced apart from each other by 1 m or more in the longitudinal direction.

[0014] In the first aspect of the present invention, each prefabricated structure divided by the horizontal and vertical dividing surfaces is provided with secondary members for connecting the vertical dividing surfaces of each prefabricated structure, and it is preferable that the horizontal width of the secondary member of one of the connecting prefabricated structures is different from the horizontal width of the secondary member of the other connecting prefabricated structure.

[0015] In the first aspect of the present invention, it is preferable that the secondary member of the one prefabricated structure is a secondary member having high strength, and the secondary member of the other prefabricated structure is a secondary member that is easy to bend.

[0016] In the first aspect of the present invention, it is preferable that the secondary member of the one prefabricated structure and the secondary member of the other prefabricated structure have fastening holes for fastening these secondary members together, and that the fastening holes have different sizes.

[0017] In the first aspect of the present invention, it is preferable that a packing material is provided on the joint surfaces of the horizontal and vertical dividing surfaces in each of the prefabricated structures.

[0018] In the first aspect of the present invention, the packing material provided on the joint surface of the vertical parting surface is preferably T-shaped.

[0019] In the first aspect of the present invention, the packing material is preferably made of an inorganic fiber blanket.

[0020] In the first aspect of the present invention, it is preferable that the housing constituting each of the prefabricated structures comprises a furnace shell made of an outer iron shell, and a heat insulating material lining the furnace shell.

[0021] The annealing furnace of the first aspect of the present invention preferably further comprises a heater for heating the steel strip being transported.

[0022] The annealing furnace of the first aspect of the present invention is preferably a vertical annealing furnace.

[0023] The second invention is a method for constructing an annealing furnace having a housing and a plurality of rows of rolls for transporting a steel strip at the top and bottom of the housing, the annealing furnace having a horizontal dividing surface dividing the furnace body in the horizontal direction, the horizontal dividing bands divided by the horizontal dividing surface further having vertical dividing surfaces dividing each of the horizontal dividing bands in a direction perpendicular to the longitudinal direction of the furnace body, placing a prefabricated structure having said horizontal and vertical dividing surfaces such that said vertical dividing surfaces are butted against each other; joining the vertical dividing surfaces to form horizontal dividing strips; The present invention relates to a method for constructing an annealing furnace, comprising the steps of:

[0024] In the second aspect of the present invention, it is preferable that the annealing furnace has a plurality of horizontal dividing surfaces, and further includes a step of stacking and installing a prefabricated structure having horizontal and vertical dividing surfaces on a horizontal dividing band or a prefabricated structure formed by joining the vertical dividing surfaces, and a step of joining the horizontal dividing surfaces.

[0025] In the second aspect of the present invention, it is preferable that the prefabricated structure is provided with a plate-shaped reinforcement material on the surface that becomes the vertical dividing surface to protect the vertical dividing surface, and that after the above-mentioned installation process, a process is provided for removing the plate-shaped reinforcement material.

[0026] In the second aspect of the present invention, each prefabricated structure divided by the horizontal and vertical dividing planes is provided with a secondary member for connecting the vertical dividing planes of each prefabricated structure, The secondary member of one prefabricated structure and the secondary member of the other prefabricated structure to be connected have fastening holes for connecting these secondary members to each other, In the step of forming the horizontal dividing band, it is preferable that the secondary members are fastened together with fasteners, the joint surfaces are welded, the fasteners are removed, and the fastening holes are welded.

[0027] In the second invention, the step of forming the horizontal dividing band preferably includes a step of sandwiching packing material between the vertical dividing surfaces and between the horizontal dividing surfaces, and the packing material sandwiched between the vertical dividing surfaces is T-shaped.

[0028] In the second aspect of the present invention, it is preferable that, prior to the installation step, the prefabricated structure is provided in advance with a heat insulating material made of inorganic fiber lining the furnace shell made of an outer iron shell.

[0029] In the second aspect of the present invention, it is preferable that, prior to the installation step, the prefabricated structure is previously equipped with a heater for heating the steel plate.

[0030] The third present invention is a prefabricated structure that constitutes the annealing furnace of the first present invention and has a horizontal dividing surface and a vertical dividing surface that divide the furnace body. Effect of the Invention

[0031] According to the annealing furnace, the construction method of the annealing furnace, and the prefabricated structure of the present invention, even an annealing furnace with a long furnace length can be installed by the prefabricated construction method. Since the prefabricated construction method is adopted, construction can be completed in a short period of time. In addition, the annealing furnace of the preferred embodiment of the present invention, in which the position of the vertical parting surface in the furnace body longitudinal direction is adjusted, has good strength and good sealing properties. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a conceptual diagram showing the configuration of a typical annealing furnace. [Diagram 2]FIG. 2 is a perspective view showing the appearance of a conventional annealing furnace. [Diagram 3] FIG. 3 is an external perspective view of the annealing furnace of the present invention. [Figure 4] FIG. 4 is a conceptual diagram showing a method for joining vertical parting surfaces in an annealing furnace according to the present invention. [Diagram 5] FIG. 5 is a flow diagram showing a method for operating an annealing furnace according to the present invention. [Figure 6] FIG. 6 is a perspective view of a prefabricated structure constituting the annealing furnace of the present invention. [Figure 7] FIG. 7 is a perspective view showing a secondary member in a vertical parting plane of the annealing furnace of the present invention. [Figure 8] FIG. 8 is a schematic diagram showing the state of packing materials on the vertical and horizontal parting planes of an annealing furnace according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] An annealing furnace as an embodiment of the present invention and a method for constructing the annealing furnace will be described below. However, the scope of the present invention is not limited to the embodiment described below. In addition, unless otherwise specified, the description "a to b" indicating a numerical range means "a or more and b or less," and also includes the meanings of "preferably greater than a" and "preferably smaller than b." Furthermore, even if the upper and lower limits of the numerical ranges in this specification are slightly outside the numerical ranges specified by the present invention, they are included in the equivalent range of the present invention as long as they have the same action and effect as those within the numerical range.

[0034] <Annealing furnace> The annealing furnace of the present invention is an annealing furnace having a housing and a plurality of rows of rolls for transporting a steel strip at the top and bottom inside the housing, The annealing furnace has a horizontal dividing surface that divides the furnace body in the horizontal direction, and the horizontal dividing bands divided by the horizontal dividing surface further have vertical dividing surfaces that divide each horizontal dividing band in a vertical direction perpendicular to the longitudinal direction of the furnace body.

[0035] In the present invention, the term "annealing furnace" mainly refers to a cold rolling annealing furnace for continuously annealing a cold rolled steel sheet, for example, a continuous annealing furnace used in a continuous annealing line (CAL) or a continuous galvanizing line (CGL), but is not limited thereto and refers to any continuous annealing furnace capable of continuously annealing a steel sheet. The annealing furnace includes an annealing furnace equipped with a cooling furnace in addition to a heating furnace and a soaking furnace. The heating furnace and the soaking furnace are preferably further equipped with a heater for heating the steel strip being transported. The annealing furnace is preferably a vertical annealing furnace.

[0036] Fig. 3 shows a perspective view of an annealing furnace 100C according to a preferred embodiment of the present invention. The illustrated annealing furnace 100C is an annealing furnace in which a heating zone and a soaking zone are integrated. A steel strip introduced from an entrance 11 of the annealing furnace 100C passes through a bottom roll 93b and a top roll 93a in this order and is transported toward an exit 19 of the furnace. A heater 93c for heating the steel strip is disposed between the bottom roll 93b and the top roll 93a.

[0037] The number of the bottom rolls 93b and the top rolls 93a is not particularly limited, and an appropriate number is adopted depending on the length of the annealing furnace. The bottom rolls 93b and the top rolls 93a are rotatably fixed to the lower and upper parts of the housing, specifically, the bottom roll chamber 10 and the top roll chamber 20, respectively.

[0038] A plurality of heaters 93c are arranged along the steel strip transport path between the top roll 93a and the bottom roll 93b. The number of heaters arranged is not particularly limited and is adjusted appropriately depending on the heating temperature of the steel strip. Alternatively, the maximum number of heaters that can be arranged may be arranged initially, and the heating temperature of the steel strip may be adjusted by stopping some of the heaters. The type of heater is not particularly limited, and a radiant tube, a tube heater, a high-frequency induction heating heater, etc. may be used. FIG. 3 shows a diagram in which a radiant tube heater is installed.

[0039] As shown in FIG. 4, the housing of the annealing furnace is composed of a furnace shell 50 made of an iron shell, and the housings of the heating furnace 92 and the soaking furnace 94 are provided with a furnace shell made of the outer iron shell 50 and a heat insulating material 40 lining the furnace shell 50. The type of heat insulating material 40 is not particularly limited as long as it has an effect of insulating the inside and outside of the annealing furnace, and an inorganic fiber blanket, an inorganic fiber block, or the like, which is a heat insulating material made of inorganic fibers, can be used. In the embodiment shown in FIG. 4, an inorganic fiber blanket 42 and an inorganic fiber blanket 44 with a low shot content are used in combination as the heat insulating material 40. In addition, an inorganic fiber block may be used instead of the inorganic fiber blanket 42, and a heat-resistant stainless steel plate, an alumina cloth, or the like may be used instead of the inorganic fiber blanket 44.

[0040] (Horizontal division strip) As shown in Fig. 3, the annealing furnace 100C of the present invention has a horizontal dividing surface 32, and each member divided by the horizontal dividing surface 32 is called a horizontal dividing band 34. Thus, the annealing furnace 100C of the present invention is formed by stacking a plurality of the horizontal dividing bands 34 in order. Specifically, horizontal dividing bands 34b to 34i are stacked in order on a horizontal dividing band 34a corresponding to the bottom roll chamber, and a horizontal dividing band 34j corresponding to the top roll chamber is stacked on top of the horizontal dividing bands 34b to 34i.

[0041] (prefabricated structure) Each horizontal dividing strip 34 divided by the horizontal dividing surface 32 further has a vertical dividing surface 36 (in FIG. 3, the vertical dividing surfaces of the horizontal dividing strips corresponding to the lower two stages and the top roll chamber are numbered, and the others are omitted). The vertical dividing surface 36 is a surface that divides each horizontal dividing strip 34 in a direction perpendicular to the longitudinal direction of the road body (X direction in FIG. 3). Each member obtained by dividing the horizontal dividing strip 34 by the vertical dividing surface 36 is called a prefabricated structure 34A, 34B (for example, the prefabricated structures of the horizontal dividing strip 34a are called prefabricated structures 34aA, 34aB from the left in the figure). In this way, in the annealing furnace 100C of the present invention, the horizontal dividing band 34 can be further divided into the prefabricated structures 36A and 36B. Therefore, by adjusting the length of the prefabricated structures 36A and 36B to a length that can be transported by a trailer, it is possible to accommodate an annealing furnace with a long furnace length.

[0042] The horizontal dividing strip 34 may have multiple vertical dividing surfaces 36 and may be configured to be divided into two or more prefabricated structures. However, for example, when the horizontal dividing strip 34 has two vertical dividing surfaces 36, the flock structure on the longitudinal end side has a gable panel, so that strength is maintained, but the prefabricated structure in the center is composed of only flat side panels.

[0043] In the present invention, it is preferable that the position of at least one vertical dividing surface in the longitudinal direction of the furnace body does not coincide with the position of the vertical dividing surface in the adjacent horizontal dividing strip in the longitudinal direction of the furnace body. In the annealing furnace shown in FIG. 3, which is a preferred embodiment of the present invention, the positions of the vertical dividing surfaces 36 of the horizontal dividing strips 34 adjacent to each other in the vertical direction in the longitudinal direction of the furnace body do not coincide. By configuring in this way, the annealing furnace can be made structurally strong. In other words, if the annealing furnace is simply divided vertically, the positions of the vertical dividing surfaces 36 in the longitudinal direction of the furnace body will coincide in the upper and lower horizontal dividing strips 34, but in this case, the structurally weak welding points will be aligned in a straight line, which will weaken the annealing furnace structurally. This can be prevented in the present invention.

[0044] Furthermore, when the positions of the vertical dividing surfaces 36 in the longitudinal direction of the furnace body are the same for the horizontal dividing strips 34 as described above, the welded parts are aligned in a straight line in both the horizontal and vertical directions, resulting in a cross-shaped joint. The inside of the annealing furnace is an atmosphere of hydrogen, nitrogen, etc., and needs to be isolated from the outside air. However, when there is a cross-shaped joint, it is very difficult to weld to ensure a seal. This can be prevented by the present invention.

[0045] The vertical parting surfaces 36 of the horizontally adjacent horizontally dividing bands 34 are preferably spaced apart from each other by 1 m or more in the longitudinal direction of the furnace body, more preferably 2 m or more, and even more preferably 3 m or more. By spaced apart the vertical parting surfaces 36 by 1 m or more in the longitudinal direction of the furnace body, the structure of the annealing furnace can be made stronger. The angle of the vertical parting plane relative to the horizontal parting plane can be appropriately selected, but is preferably 80° to 90° (vertical), and more preferably 88° to 90° (vertical). The vertical parting plane may be a straight line, or may be bent or curved.

[0046] (Secondary parts) As described below in the construction method of the annealing furnace, when installing each prefabricated structure and joining the divided surfaces together, it is preferable that the prefabricated structure is provided with a secondary member for joining the divided surfaces in order to maintain the joining strength of the divided surfaces. The secondary members may be, but are not limited to, a U-shaped member (channel / channel steel) 52 and an L-shaped member (angle / angle steel) 54 shown in Fig. 4, and may be of various shapes that can maintain the adhesion and joint strength between the divided surfaces. The secondary members are joined to the furnace shell 50 constituting the prefabricated structure by a normal method such as welding. By joining the secondary member provided on one prefabricated structure to the secondary member provided on the other prefabricated structure by welding, the prefabricated structures can be connected and the sealing can be ensured.

[0047] In the annealing furnace of the present invention, the dividing surfaces are the horizontal dividing surface 32 and the vertical dividing surface 36. When the horizontal dividing surface 32 is joined, the weight of the upper horizontal dividing strip 34 makes it possible to bring the horizontal dividing surface 32 into close contact with each other, which makes it easy to perform welding while maintaining the joining strength. On the other hand, when the vertical dividing surface 36 is joined, a separate measure is required to bring the prefabricated structures into close contact with each other. Various forms for maintaining the adhesion and joining strength of the dividing surfaces, particularly the vertical dividing surface 36, are described below.

[0048] Secondary member width It is preferable that the secondary members of one prefabricated structure and the secondary members of the other prefabricated structure to be connected have different horizontal widths (W1 and W2 in FIG. 4). Here, the horizontal width means the horizontal width in the position in which the prefabricated structure is constructed as an annealing furnace. If the widths of the secondary members are different, when these secondary members are butted together, the end of one secondary member and the end of the other secondary member will not be flush with each other, and one will protrude. This improves workability during welding.

[0049] - Secondary member shape It is preferable that the secondary member of one prefabricated structure to be connected is a secondary member with high strength, and the secondary member of the other prefabricated structure is a secondary member that is easy to bend. An example of a secondary member with high strength is the U-shaped member (channel) 52 connected to the prefabricated structure on the left side of Figure 4. Also, an example of a secondary member that is easy to bend is the L-shaped member (angle) 54 connected to the prefabricated structure on the right side of Figure 4.

[0050] By making one of the connecting members strong, the joining strength of the divided surfaces and the strength of the entire structure can be improved, and by making the other connecting member a secondary member that is easy to bend, the prefabricated structures can be made to adhere to each other. Therefore, this embodiment is preferable when connecting vertical divided surfaces that are difficult to adhere to.

[0051] Fastening holes It is preferable that the secondary members of one prefabricated structure and the secondary members of the other prefabricated structure to be connected have fastening holes 52a, 54a for fastening these secondary members together. The fastening holes 52a, 54a refer to holes for inserting fasteners 60a, 60b such as bolts and nuts. When joining prefabricated structures together, the fasteners 60a, 60b are inserted into the fastening holes 52a, 54a and fastened together to bring the secondary members into close contact with each other. In this state, the joint surfaces of the secondary members are welded to ensure good adhesion between the prefabricated structures. The fasteners 60a, 60b are removed after welding the secondary members.

[0052] In addition, it is preferable that the sizes of the fastening holes 52a, 54a of one secondary member and the other secondary member to be connected are different from each other. From the viewpoint of ensuring the sealing property between the prefabricated structures, after removing the fasteners 60a, 60b, the periphery of the fastening holes 52a, 54a is welded, but if the sizes of the fastening holes 52a, 54a are made different from each other, the ends of the fastening holes 52a, 54a will not be flush with each other, and one will protrude. This improves the workability during welding. The structure having the fastening holes 52a, 54a can achieve adhesion between the prefabricated structures by using the fasteners 60a, 60b. Therefore, it can be said that this is a preferable form when connecting vertically divided surfaces. The interval between the fastening holes is not particularly limited, but a pitch of 200 to 400 mm is preferable. The size of the fastening holes is not particularly limited, but a diameter of 10 mm or more is preferable, and a diameter of 16 mm or more is more preferable. The difference in size of the fastening holes is not particularly limited, but it is preferable that the difference in diameter be 6 mm or more, and more preferably 10 mm or more.

[0053] (Packing material) As shown in Fig. 4 as an example of the joint of the vertical dividing surface 36, it is preferable to provide a packing material 46 at the joint surface between the horizontal dividing surface 32 and the vertical dividing surface 36 in each prefabricated structure. The joint surface provided with the packing material 46 refers to the joint surface between the insulation material 40 provided in one prefabricated structure and the insulation material 40 provided in the other prefabricated structure. By providing the packing material 46, there are no gaps in the insulation material 40, improving the insulation performance and preventing heat from penetrating into the outer wall portion (furnace shell) of the prefabricated structure.

[0054] From the viewpoint of eliminating the above-mentioned gaps, it is preferable that the packing material 46 is folded as shown in FIG. 4 before use. This makes it possible to more effectively eliminate gaps in the insulation material 40 by the restoring force of the folded packing material 46. The shape of the packing material applied to the horizontally divided surface 32 is not particularly limited, and for example, a strip-shaped packing material that covers the joint surface of the horizontally divided surface 32 can be used. In contrast, the shape of the packing material applied to the vertically divided surface 36 is preferably T-shaped. By being T-shaped, the vertical position of the packing material 46 on the vertically divided surface 36 can be fixed, and the risk of the packing material slipping off and causing gaps can be reduced. In the embodiment of FIG. 4, both the folded strip-shaped packing material and the folded T-shaped packing material are arranged on the joint surface of the vertically divided surface.

[0055] The material of the packing material 46 is not particularly limited, and it can be formed from a material having heat resistance, but for example, a packing material made of an inorganic fiber blanket can be preferably used. Specifically, an example of the inorganic fiber blanket that can be used is MAFTEC manufactured by Mitsubishi Chemical Corporation. The method of manufacturing the T-shaped packing material is not particularly limited, but it can be a method of folding two inorganic fiber blankets, overlapping them in a T shape, and fixing the overlapping parts with an alumina rope.

[0056] <Annealing furnace construction method> The above-mentioned annealing furnace, i.e., an annealing furnace having a housing and multiple rows of rolls for transporting a steel strip at the top and bottom inside the housing, which has a horizontal dividing surface 32 that divides the furnace body in the horizontal direction, and which horizontal dividing strips 34 divided by the horizontal dividing surface 32 further have vertical dividing surfaces 36 that divide each horizontal dividing strip 34 in a direction perpendicular to the longitudinal direction of the furnace body, can be constructed by the following method. The construction method of the annealing furnace of the present invention includes the steps of installing a prefabricated structure having a horizontal parting surface 32 and a vertical parting surface 36 so that the vertical parting surfaces 36 are abutted against each other, and joining the vertical parting surfaces 36 to form a horizontal parting strip 34.

[0057] In addition, a preferred embodiment of the method for constructing an annealing furnace is a method for constructing an annealing furnace having a plurality of horizontal dividing surfaces 32, and further includes a step of stacking and installing a prefabricated structure having the horizontal dividing surfaces 32 and the vertical dividing surfaces 36 on top of the horizontal dividing band 34 formed by joining the vertical dividing surfaces 36 or a prefabricated structure, and a step of joining the horizontal dividing surfaces 32.

[0058] A flow diagram of a preferred embodiment of the annealing furnace construction method of the present invention is shown in Figure 5. In the "prefabricated structure installation step" S1, the lowest prefabricated structure is installed, and then in the "horizontal dividing strip formation step" S2, the vertical dividing surfaces of the prefabricated structures are joined together to form the lowest horizontal dividing strip. In the "prefabricated structure installation process" of S3, the second tier of prefabricated structures is installed, and then in the "horizontal dividing strip formation process" of S4, the vertical dividing surfaces of the prefabricated structures are joined together, and the horizontal dividing strips of the first tier and the second tier are also joined together to form the second tier of horizontal dividing strips. Note that in S4, the joining of the vertical dividing surfaces or the joining of the horizontal dividing surfaces can be performed in any order. Thereafter, by repeating S3 and S4 multiple times, horizontal dividing bands are formed in sequence, and finally, a top roll chamber is formed in the same manner by S3 and S4, and an annealing furnace is constructed by the construction method of the present invention.

[0059] In the annealing furnace 100C shown in Fig. 3, in S1, the prefabricated structures 34aA and 34aB are installed, and in S2, the vertical dividing surfaces 36 of these prefabricated structures are joined to form the horizontal dividing zone 34a, i.e., the bottom chamber 34a at the bottom. When the existing bottom chamber is left in the furnace body renewal work, the method of the present invention may be used to renew the furnace body above the bottom chamber. In S3, prefabricated structures 34bA and 34bB are installed, and in S4, the vertical dividing surfaces 36 of these prefabricated structures are joined to form the second horizontal dividing strip 34b, and the horizontal dividing surfaces 32 of the previously formed horizontal dividing strip 34a and horizontal dividing strip 34b are joined. Thereafter, by repeating S3 and S4, the horizontal dividing zones 34c to 34i are successively formed, and finally, the top roll chamber 34j is similarly formed by S3 and S4, and the annealing furnace 100C is constructed by the construction method of the present invention.

[0060] In the above, we have explained a method of installing a prefabricated structure on top of the horizontal partition 34 formed by joining the vertical partition surfaces 36. However, it is also possible to install a prefabricated structure and then install another prefabricated structure on top of it, and first join the horizontal partition surfaces 32 between them and then join each of the vertical partition surfaces 36, or to first join each of the vertical partition surfaces 36 and then join the horizontal partition surfaces 32, and these forms are also within the scope of the present invention.

[0061] Each step will be described in detail below. (Prefabricated structure installation process) FIG. 6 shows a perspective view of the prefabricated structure 34B. The prefabricated structure is fabricated in advance in a factory and then transported to the construction site. In the prefabricated structure installation process, the transported prefabricated structure is installed at a position where the annealing furnace is to be constructed, for example, by a crane. The insulating material 40 is exposed at the vertical division surface 36 of the prefabricated structure fabricated in the factory. It is desired to protect the exposed insulating material 40 during transportation from the factory to the construction site, storage at the construction site, and even when hanging by a crane. For this reason, it is preferable that the prefabricated structure is provided with a plate-shaped reinforcement material 70 for protecting the vertical division surface 36. In addition, when the prefabricated structure is transported from the factory to the construction site, it is necessary to increase the strength of the prefabricated structure so that it does not deform. For this reason, it is preferable that the prefabricated structure is provided with a plate-shaped reinforcement material 70.

[0062] When using a prefabricated structure equipped with plate-like reinforcement 70, it is necessary to have a process of removing the plate-like reinforcement 70 before joining the vertical parting surface 36. The plate-like reinforcement 70 may be removed before the prefabricated structure is hoisted by a crane, but it is preferable to remove it after installing it near the construction position in order to prevent deformation of the prefabricated structure when it is hoisted by the crane. Here, near the construction position means a position shifted by about 100 mm from the construction position, and the plate-like reinforcement 70 is first installed at a position off to ensure space for removing it, and then the plate-like reinforcement 70 is removed and then shifted to the construction position to join the vertical parting surface 36.

[0063] The means for attaching the plate-shaped reinforcement 70 to the prefabricated structure is not particularly limited, but for example, it is possible to fix it by utilizing fastening holes 52a, 54a formed in the secondary members 52, 54 formed on the vertical dividing surface 36 of the prefabricated structure.

[0064] It is preferable that the prefabricated structure is provided with insulation 40 made of inorganic fiber lining the furnace shell 50 made of the outer iron shell before the prefabricated structure installation process. It is also preferable that the prefabricated structure is provided with a heater 93c for heating the steel plate before the prefabricated structure installation process. In other words, by installing insulation, a heater, or both in the prefabricated structure in advance at the manufacturing stage in the factory, it is possible to simply install and join the transported prefabricated structures in order at the construction site, further shortening the construction time.

[0065] (Horizontal division strip formation process) In the horizontal dividing strip forming process, the vertical dividing surfaces 36 of the installed prefabricated structure are joined together to form the horizontal dividing strip 34. The joining of the vertical dividing surfaces 36 is preferably performed by joining secondary members provided on the vertical dividing surfaces 36 by welding. As described above, it is difficult to achieve adhesion at the vertical dividing surface 36, so it is preferable that the secondary members of the vertical dividing surface 36 of one prefabricated structure and the secondary members of the vertical dividing surface 36 of the other prefabricated structure be provided with fastening holes 52a, 54a for connecting these secondary members to each other.

[0066] In the horizontal dividing band forming process, as shown in FIG. 4, it is preferable to fasten the secondary members together with fasteners 60a, 60b. This allows the secondary members to be in close contact with each other. It is then preferable to weld the joint surfaces, remove the fasteners, and then weld the fastening holes. In the embodiment of FIG. 4, the fastening hole of the secondary member on the right side of the figure is larger than the fastening hole of the secondary member on the left side. Therefore, it is possible to weld from the right side. A perspective view of the joined secondary members from the right side is shown in FIG. 7. In this way, sealing can be ensured by welding the periphery of the fastening hole from the right side.

[0067] (Process of sandwiching packing material) The horizontal dividing band forming step preferably includes a step of sandwiching packing material 46 between the vertical dividing surfaces 36 and between the horizontal dividing surfaces 32. Fig. 8 is a schematic diagram showing the state in which packing material 46A is sandwiched between the vertical dividing surfaces 36 and packing material 46B is sandwiched between the horizontal dividing surfaces 32, and the divided surfaces are joined together. In Fig. 8, some of the structure is omitted in order to show the appearance of the packing materials 46A and 46B. The packing material 46B sandwiched between the horizontal dividing surfaces 32 is placed on the horizontal dividing surface 32 of the already formed horizontal dividing strip 34 before the next prefabricated structure is installed during the prefabricated structure installation process.

[0068] Before the prefabricated structure is installed and the vertical dividing surfaces 36 are butted against each other, the packing material 46A sandwiched between the vertical dividing surfaces 36 is installed between the vertical dividing surfaces 36. The packing material 46A sandwiched between the vertical dividing surfaces 36 is preferably T-shaped. EXAMPLES

[0069] Hereinafter, as an embodiment, a construction example of the annealing furnace 100C including the heating furnace 92 shown in FIG. 3 will be described. Each prefabricated structure constituting the annealing furnace 100C was fabricated in a factory. The width of each prefabricated structure is 3 m, and the vertical height of each prefabricated structure is 2.7 m. The longitudinal length of the prefabricated structure (bottom roll chamber) 34aA on the left side of the figure is 11 m, and the longitudinal length of the prefabricated structure (bottom roll chamber) 34aB on the right side of the figure is also 11 m. The longitudinal length of the prefabricated structure 34bA is 12 m, the longitudinal length of the prefabricated structure 34bB is 10 m, the longitudinal length of the prefabricated structure 34cA is 10 m, and the longitudinal length of the prefabricated structure 34cB is 12 m. The lengths of each prefabricated structure above them are similar. The longitudinal length of the top roll chamber 34jA on the left side is 11.5 m, and the longitudinal length of the top roll chamber 34jB on the right side is 10.5 m.

[0070] The inside of each prefabricated structure was lined with insulation material 40 at the factory. A channel 52 and an angle 54 having fastening holes as shown in FIG. 4 are attached to the vertical division surface 36 and the horizontal division surface 32 of each prefabricated structure. In the vertical division surface 36, the channel 52 is attached to the prefabricated structure on the left side of the figure, and the angle is attached to the prefabricated structure on the right side of the figure. In each prefabricated structure, an angle is attached to the upper horizontal division surface, and a channel is attached to the lower horizontal division surface. A plate-shaped reinforcing plate 70 having a thickness of 6 mm is attached to the vertical division surface 36 via the angle 54 or the channel 52. A brace, which is a reinforcing material, is attached to the horizontal division surface 32.

[0071] Each prefabricated structure fabricated in the above-mentioned factory was transported to the construction site. The length of each prefabricated structure was within the range that could be loaded onto a trailer, and it was possible to transport it to the construction site. Among the transported prefabricated structures, the prefabricated structure 34aA corresponding to the bottom roll chamber was first installed at the construction site using an in-house crane. After installation at the construction site, the plate-shaped reinforcing plate 70 and the brace were removed from the prefabricated structure 34aA.

[0072] The prefabricated structure 34aB was installed at the construction site using a crane on the premises. After installation at the construction site, the plate-shaped reinforcing plate 70 and brace were removed from the prefabricated structure 34aB. Two sheets of MAFTEC 6p12.5t were folded in half, and the overlapping portion was sewn with an alumina rope to form a T-shaped inorganic fiber blanket (packing material 46A) which was installed on the vertical division surface 36. In addition, MAFTEC 6p12.5t (packing material 46B) was folded in half and installed without gaps on the horizontal division surface 32 so as to cover the end surface of the insulation material 40 of the horizontal division surface 32. The packing was fixed to the insulation material installed in the annealing furnace at 300 mm pitches using L-shaped pins with a length of 100 m. The channel and angle joined to the vertical dividing surface 36 were fastened with a washer and an M16 bolt from the channel 52 side, and with a collar, washer, and nut from the angle 54 side. The joint surfaces of the channel 52 and the angle 54 were spot welded at 200 mm pitch. The bolts, nuts, washers, and collars were removed, and the joint surfaces of the bolt holes were line welded from the larger side of the fastening hole (the right side in the figure). Then, the joint surfaces of the channel 52 and the angle 54 were line welded. As a result of the above, the first horizontal dividing strip 34a was constructed.

[0073] Thereafter, the second-stage prefabricated structures 34bA and 34bB were installed and joined by an on-site crane using the same procedure as above, and the second-stage horizontal dividing strip 34b was constructed. Thereafter, the first-stage horizontal dividing strip 34a and the second-stage horizontal dividing strip 34b were line-welded from above (i.e., from the angle 54 side with the smallest horizontal width) to join the horizontal dividing surface 32.

[0074] By repeating the above steps, the horizontal dividing bands 34a to 34j were formed, and the annealing furnace 100C was constructed. The radiant tube was installed in a predetermined position on the prefabricated structure after each prefabricated structure was installed in a predetermined position by a crane.

[0075] According to the annealing furnace and the construction method of the annealing furnace of the present invention, even an annealing furnace with a long furnace length can be installed by the prefabricated construction method. Therefore, it is possible to construct an annealing furnace with a long furnace length by the prefabricated construction method inland where transportation by trailer is required. Since the prefabricated construction method is adopted, construction can be performed in a short period of time, leading to reduction in time and labor costs. Furthermore, the constructed annealing furnace has structural strength and has a sealing property that isolates the inside from the outside. [Explanation of symbols]

[0076] 100C: Annealing furnace 11: Entrance 19: Exit 91: Steel strip 93a: Top roll 93b: Bottom roll 93c:Heater 32: Horizontal dividing plane 36: Vertical dividing plane 34: Horizontal division strip 34A, 34B: Prefabricated structure 52: Channel 54: Angle 40: Insulation 46: Packing material 50: Furnace shell

Claims

1. An annealing furnace having a housing and a plurality of rows of rolls at the top and bottom inside the housing for transporting a steel strip, The annealing furnace has a horizontal dividing surface that divides the furnace body in the horizontal direction, and the horizontal dividing band divided by the horizontal dividing surface further has a vertical dividing surface that divides the horizontal dividing band in a direction perpendicular to the longitudinal direction of the furnace body, The horizontal division surface is provided in a plurality of positions, At least one of the vertical dividing surfaces has a furnace body longitudinal position that does not coincide with a furnace body longitudinal position of the vertical dividing surface in the adjacent horizontal dividing strip; Annealing furnace.

2. 2. The annealing furnace according to claim 1, wherein the vertically adjacent horizontally divided bands are spaced apart from each other in the longitudinal direction of the furnace body by 1 m or more.

3. 3. The annealing furnace according to claim 1 or 2, wherein each prefabricated structure divided by the horizontal and vertical dividing surfaces is provided with a secondary member for connecting the vertical dividing surfaces of each prefabricated structure, and the horizontal width of the secondary member of one prefabricated structure to be connected is different from the horizontal width of the secondary member of the other prefabricated structure to be connected.

4. 4. The annealing furnace according to claim 3, wherein the secondary member of said one prefabricated structure is a secondary member having high strength, and the secondary member of said other prefabricated structure is a secondary member which is easy to bend.

5. 5. The annealing furnace according to claim 3 or 4, wherein the secondary member of the one prefabricated structure and the secondary member of the other prefabricated structure have fastening holes for fastening these secondary members together, and the fastening holes have different sizes.

6. The annealing furnace according to any one of claims 3 to 5, wherein a packing material is provided on a joint surface between the horizontally divided surface and the vertically divided surface in each of the prefabricated structures.

7. The annealing furnace according to claim 6, wherein the packing material provided at the joint surfaces of the vertically divided surfaces is T-shaped.

8. 8. The annealing furnace according to claim 6, wherein the packing material is made of an inorganic fiber blanket.

9. The annealing furnace according to any one of claims 3 to 8, wherein the housing constituting each of the prefabricated structures comprises a furnace shell made of an outer iron shell and a heat insulating material lining the furnace shell.

10. The annealing furnace according to any one of claims 1 to 9, further comprising a heater for heating the transported steel strip.

11. The annealing furnace according to any one of claims 1 to 10, which is a vertical annealing furnace.

12. A method for constructing an annealing furnace having a housing and a plurality of rows of rolls for transporting a steel strip at a top and bottom inside the housing, comprising the steps of: The annealing furnace has a horizontal dividing surface that divides the furnace body in the horizontal direction, and the horizontal dividing bands divided by the horizontal dividing surface further have vertical dividing surfaces that divide each horizontal dividing band in a direction perpendicular to the longitudinal direction of the furnace body, a prefabricated structure installation step of installing a prefabricated structure having the horizontal division surface and the vertical division surface so that the vertical division surface is butted against each other; joining the vertical dividing surfaces to form horizontal dividing strips. Equipped with The annealing furnace has a plurality of the horizontal parting surfaces, At least one of the vertical dividing surfaces has a furnace body longitudinal position that does not coincide with the furnace body longitudinal position of the vertical dividing surface in the adjacent horizontal dividing strip; How to install an annealing furnace.

13. A method for constructing an annealing furnace having a plurality of horizontally divided surfaces, The method for constructing an annealing furnace according to claim 12, further comprising: a prefabricated structure installation step of stacking and installing a prefabricated structure having horizontal and vertical dividing surfaces on the horizontal dividing strip formed by joining the vertical dividing surfaces or on the prefabricated structure; and a step of joining the horizontal dividing surfaces.

14. 14. The method for constructing an annealing furnace according to claim 12 or 13, further comprising the steps of: providing the prefabricated structure with a plate-shaped reinforcing material for protecting a surface that is to become a vertical parting surface; and removing the plate-shaped reinforcing material after the prefabricated structure installation step.

15. Each prefabricated structure divided by the horizontal and vertical dividing surfaces includes a secondary member for connecting the vertical dividing surfaces of each prefabricated structure; The secondary member of one prefabricated structure and the secondary member of the other prefabricated structure to be connected have fastening holes for connecting these secondary members to each other; In the step of forming the horizontal dividing band, the secondary members are fastened together with fasteners, the joint surfaces are welded, the fasteners are removed, and the fastening holes are welded. The construction method for an annealing furnace according to any one of claims 12 to 14.

16. The step of forming the horizontal dividing bands includes a step of sandwiching a packing material between the vertical dividing surfaces and between the horizontal dividing surfaces, The packing material sandwiched between the vertically divided surfaces is T-shaped. The construction method for an annealing furnace according to any one of claims 12 to 15.

17. The construction method for an annealing furnace according to any one of claims 12 to 16, wherein, prior to the prefabricated structure installation step, the prefabricated structure is provided in advance with a heat insulating material made of inorganic fibers lining a furnace shell made of an outer iron shell.

18. The construction method for an annealing furnace according to any one of claims 12 to 17, wherein the prefabricated structure is previously equipped with a heater for heating a steel plate prior to the prefabricated structure installation step.

19. The annealing furnace according to any one of claims 1 to 11, A prefabricated structure with horizontal and vertical dividing planes that separate the furnace body.

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