JP5410065B2 - Transport structure - Google Patents

Description

  The present invention relates to the transportation of rain gutter-like semi-cylindrical tubes and square plates used in facilities for transporting or distributing iron ore, coke, limestone, etc., as raw materials for iron making disposed in a blast furnace of a steelmaking machine. It relates to a structural body.

  In the upper processes such as ironworks coke factory, sintering factory, blast furnace factory, etc., many facilities are provided to transport iron ore, coke, limestone, etc. as raw materials for iron making. Since these facilities are worn or lost due to the contact of the iron-making raw material when the iron-making raw material is conveyed, it is necessary to perform maintenance and inspection at a predetermined cycle.

  In particular, if the swiveling chute that distributes iron ore, coke, limestone, etc. deployed in the blast furnace is worn or missing, it may not be possible to obtain the desired dispersion behavior, which may reduce production quality and adversely affect the operation of the blast furnace. is there.

  On the other hand, as a method for maintaining high production, it is effective to shorten the period of maintenance and inspection and the repair period. For this reason, it is an important issue to extend the life of equipment used for conveying or dispersing steelmaking raw materials.

  A conventional turning chute will be described. The swivel chute conveys (slides down) iron ore, coke, limestone and the like (hereinafter referred to as blast furnace charge) supplied from the hopper toward the bottom of the furnace. The swivel chute has an inclined portion that gradually inclines downward toward the outside in the furnace width direction, and the blast furnace charge supplied from the hopper rolls after colliding with the inclined surface of the inclined portion. Move toward the space inside the blast furnace. At this time, since the inclined surface receives severe impact and sliding wear from the blast furnace charge, a protective liner having wear resistance and impact resistance is used as a countermeasure against deficiency and sliding wear.

  As a protective liner, C: 5.5 wt%, Cr: 22 wt%, Mo: 7.0 wt%, Nb: 6.5 wt%, W: 2.0 wt%, V on the surface where the blast furnace charge collides or rolls A structure in which a high carbon high chromium cast iron overlay material consisting of 1.0 wt% and the balance being Fe is welded is known. Although this build-up material has extremely high high-temperature hardness, it is very brittle, so that it is difficult to laminate the build-up weld to a thickness of 15 mm or more. Moreover, when it was used in the structure of a single liner having a thickness of 15 mm or less, it peeled off in about 1 to 2 months and had to be replaced in a short period.

  As a countermeasure, a protective liner in which two or more liners are stacked is proposed, and a schematic configuration thereof is shown in FIG. The wear-resistant plate 301 is configured by welding a build-up weld layer 301B to the surface of the substrate 301A. A high-carbon high-chromium cast iron-based build-up material can be used for the build-up weld layer 301B. Of each wear-resistant plate 301, a flange-shaped curved portion 3001 </ b> A is formed at the upstream end of the blast furnace charge in the sliding direction, and this curved portion 3001 </ b> A is fastened to the bottom plate portion 302 using a bolt 303. It is fixed. On the other hand, the end of the blast furnace charge downstream in the sliding direction is in a free state. This protective liner is called a fish plate type because its appearance looks like fish scales.

  However, the collision part of the blast furnace charge that is dropped and supplied from the hopper is damaged by an impact load in two to three months, and repair is required. Moreover, there is a possibility that the boundary portion between adjacent wear-resistant plates 301 becomes a step and disturbs the flow of the blast furnace charge.

  A configuration shown in FIG. 6 is known to compensate for the shortcomings of this fish plate type protective liner. FIG. 6 discloses a type of protective liner called a smooth liner. The protective liner includes a general structural steel 401 and a plurality of studs 402 erected on the bottom of the container 401. The container 401 is formed with a protective layer 403 of 40 to 60 mm in which a melted material in which a high carbon high chromium cast iron material is dissolved is cast.

  The smooth liner can compensate for the disadvantage of the fish plate that the apparent thickness of the protective layer is increased and the flow of the blast furnace charge is disturbed due to the flat surface. However, since it is a cast product, it is lower in hardness than welded products with similar components and the carbide particles are coarse, so it lacks wear resistance and impact resistance, especially blast furnace equipment located directly under the hopper. There is a risk that the service life may be shortened in the collision part of the entry.

  Therefore, as shown in FIG. 7, a configuration has been proposed in which a protective layer 404 in which tungsten carbide of carbide metal is scattered is formed on the surface of the protective liner of FIG. However, since this protective liner is manufactured by a method in which a cemented carbide W carbide is laid on the bottom of the box and a molten high carbon high chromium material is poured from the top, the thickness of the W carbide is limited to a maximum of 10 mm. . In addition, the base material is brittle because of the high-carbon high-chromium cast iron, and it was not sufficient for impact cracking and chipping caused by falling ore.

  Moreover, the protective liner shown in FIG. 8 is disclosed. The protective liner includes a plain steel or stainless steel container 501 and a stud 502 erected on the bottom surface of the container 501. The container 501 is filled with a casting 503 in which a melted material obtained by melting a carbon high chromium cast iron material is cast. The container 501 is formed with an accommodating portion 501A extending in a predetermined direction. A large number of blast furnace charges 504 are loaded in the accommodating portion 501A.

  However, in order to improve wear resistance and impact resistance, the housing portion 501A must be formed deeply, and thus the protective liner has to be thickened. As a result, the transport path of the blast furnace charge formed on the protective liner is narrowed, and the supply amount of the blast furnace charge may be reduced. In addition, during the turning operation, the blast furnace charge may fall from the side of the protective liner.

As an improvement measure, Patent Document 1 discloses a configuration illustrated in FIG. FIG. 9 is a perspective view partially showing the structure of the protective liner of Patent Document 1. As shown in FIG. As shown in FIG. 9, Patent Document 1 discloses that a plurality of openings 601A are formed in a zigzag pattern on a plate 601 made of low carbon steel, alloy steel or stainless steel, and high carbon high chromium welding is performed on these openings 601A. Disclosed is a protective liner in which a material or a material in which carbide is dispersed (abrasion resistant / impact resistant material 602) is welded. The opening 601A is formed in a hexagonal shape when viewed in the plate thickness direction.
JP 2002-180115 A

  According to the configuration of Patent Document 1, the thickness of the welded layer made of the wear / shock resistant material 602 is 30 mm or more, and high wear resistance and impact resistance can be obtained. However, in order to make the weld layer 30 mm or more in thickness, using an enclosing welding method, an electroslag welding method, or the like, while adjusting the addition time of carbide so as not to melt in the arc molten pool and crack. Since a plurality of overlay welding layers must be laminated, it takes time and effort. In addition, since the thermal expansion coefficients of the plate 601 and the wear / shock resistant material 602 are different, the opening 601A of the plate 601 may be cracked.

  Therefore, an object of the present invention is to provide a protective plate that has impact resistance and wear resistance and is easy to manufacture.

In order to solve the above problems, a transport structure according to the present invention is (1) a transport structure that forms a block mineral transport path by arranging a plurality of plates on a fixed surface, The plate has a substrate and a weld layer welded on the substrate, and the substrate and the weld layer in each plate are alternately arranged in the transport direction of the massive mineral , Of the plate, the downstream end in the transport direction is fillet welded to the fixed surface, and the upstream end is spaced from the fixed surface .

( 2 ) In the configuration of ( 1 ), the angle of the plate with respect to the fixed surface (θ in FIG. 4) is preferably set to 30 degrees or less.

According to the configuration of ( 2 ), the thickness of the build-up weld layer can be made sufficiently thicker with respect to the lump mineral supplied by dropping, and the impact resistance and wear resistance can be further enhanced.

( 3 ) In the configurations of (1) to ( 2 ), in each of the plates, the weld layer may be positioned upstream of the substrate in the transport direction.

( 4 ) In the configurations of (1) to ( 3 ), it is preferable to provide an urging means for urging the plate located most downstream in the conveyance direction among the plurality of plates to the upstream side in the conveyance direction. .

According to the structure of ( 4 ), the impact force received at the time of contact of the lump mineral can be relieved with a simple structure.

( 5 ) In the configurations of (1) to ( 4 ), the substrate has a higher coefficient of thermal expansion than the overlay welding layer.

( 6 ) In the configurations of (1) to ( 5 ), the plates adjacent in the transport direction are separated from or in contact with each other without being joined to each other. By making the adjacent plates non-joined, the occurrence of cracks due to thermal expansion can be suppressed.

( 7 ) In the configurations of (1) to ( 6 ), the transfer structure can be used for a distribution chute arranged at the top of a blast furnace.

According to the present invention, it is possible to provide a protection plate that has impact resistance and wear resistance and is easy to manufacture. Further, by using fillet welding as a fixing method, it is possible to mitigate the impact force received when the massive mineral comes into contact. Furthermore, by utilizing the space formed between the plate and the fixed surface, another plate adjacent to the plate can be easily welded to the fixed surface, and the manufacturing efficiency can be improved.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of the top of a blast furnace. The turning chute 11 is attached to the vertical chute 12 via an inclination adjusting shaft portion 13. The vertical chute 12 is provided with a tilting device (not shown). When this tilting device is operated, the turning chute 11 rotates about the inclination adjusting shaft portion 13 as a rotation axis, and the inclination of the turning chute 11 with respect to the X axis is adjusted. The X axis is a shaft portion that extends vertically through the inclination adjustment shaft portion 13.

  The vertical chute 12 is connected to a rotation drive device (not shown). When the rotation driving device is operated, the turning chute 11 and the vertical chute 12 rotate integrally with the X axis as the rotation axis. The vertical chute 12 is connected to the hopper portion 14. The hopper portion 14 is connected to the furnace top bunker 16. A gate 15 is provided between the hopper portion 14 and the furnace top bunker 16. The gate 15 rotates around the gate rotation axis 17.

  A blast furnace charge (bulk mineral) A is stored in the furnace top bunker 16. When the gate 15 is switched from the closed state to the opened state, the blast furnace charge A stored in the furnace top bunker 16 until then flows into the hopper portion 14. The blast furnace charge A includes iron ore, coke, and limestone, but other auxiliary materials (for example, waste plastic) may be included as necessary.

  The blast furnace charge A flowing into the hopper 14 is supplied to the turning chute 11 through the vertical chute 12. The blast furnace charge A supplied to the turning chute 11 moves while sliding in the turning chute 11 and is put into the space in the blast furnace 1. Here, by using the turning chute 11, the deposition position of the blast furnace charge A can be easily changed. Thereby, the blast furnace charge A can be uniformly dispersed in the blast furnace 1.

  Next, the structure of the turning chute 11 will be described in detail with reference to FIG. FIG. 2 is a schematic view of the liner of the turning chute, and the arrows indicate the direction in which the blast furnace charge A moves. The blast furnace charge A dropped and supplied from the hopper 14 moves toward the inside of the blast furnace 1 while sliding down the surface of the liner (conveying structure) 110. The sliding direction of the blast furnace charge A corresponds to the “conveying direction” described in the claims.

  The liner 110 includes a sliding part 111, a bottom plate part (fixed surface) 121 and an end plate 131 to which the sliding part 111 is fixed by welding. The sliding portion 111 is configured by arranging an impact / wear resistant plate 112 side by side in the sliding direction of the blast furnace charge A. The impact / abrasion resistant plate 112 includes a substrate 112A and a build-up weld layer 112B that is build-up welded on the substrate 112A.

  For the substrate 112A, a general steel sheet (common name: mild steel sheet) such as a general structural rolled steel sheet (JIS: SS material) or a welded structural rolled steel material (JIS: SM material) can be used. The build-up welding material to be welded as the build-up weld layer 112B includes carbon steel, alloy steel, stainless steel, Ni, high chromium cast iron, W, Cr, Mo, V, Nb, and one or more carbides of Ti. Co metal cermets can be used.

  Furthermore, austenitic manganese steel whose main component is manganese can also be used. Typically, a composite material in which 14% manganese steel is used as a matrix and tungsten carbide particles are dispersed and mixed so as to occupy 20 to 70% in terms of the cross-sectional area ratio is preferable. The tungsten carbide particles preferably contain 3 to 15% cobalt, and the particle size is preferably 8 mm or less at maximum and 0.5 to 1.5 mm on average.

  Since this composite material uses 14% manganese steel for the matrix, it is also very suitable for wear situations in which a massive wear medium falls from the height with a drop and gives an impact load to the wear surface. It has been confirmed that it is a build-up material.

As for the blast furnace raw material, it is considered preferable to use iron ore with a particle size of about 30 to 50 mm in order to suppress variation in various chemical changes in the blast furnace. Accordingly, the weight of at least one lump of iron ore is about 100 to 600 g, and the surface pressure applied when this lump falls from the hopper portion 14 with a drop and directly hits the sliding portion 111 is 490 N / cm ² or more. It is assumed that Since the composite material described above has characteristics suitable for such an impact load, it is optimal as a material constituting the impact / abrasion resistant plate 112.

  The shock / wear resistant plate 112 is arranged so that the substrate 112A and the build-up weld layer 112B are aligned in the sliding direction of the blast furnace charge A. The substrate 112A is located downstream of the build-up weld layer 112B in the sliding direction of the blast furnace charge A. The end of the impact / wear resistant plate 112 on the downstream side in the sliding direction is welded to the plate welding surface (fixed surface) 121A of the bottom plate 121, and the end on the upstream side in the sliding direction is the bottom of the bottom plate 121. It is separated from the plate welding surface 121A.

  That is, the impact / abrasion resistant plate 112 is welded (fillet welded) in an inclined state with respect to the plate welding surface 121A. Note that the fillet welded portion is referred to as a fillet weld portion 201.

  Thus, by arranging the wear-resistant / impact-resistant plate 112 so as to be inclined with respect to the plate welding surface 121A, a space for performing fillet welding can be secured. Thereby, each impact-resistant and abrasion-resistant plate 112 can be fixed more firmly.

  When the blast furnace charge A falls and collides with the impact resistant / wear resistant plate 112, the impact resistant / wear resistant plate 112 slightly swings around the fillet weld 201 (sliding down of the impact resistant / wear resistant plate 112). The end on the upstream side in the direction approaches or separates from the plate welding surface 121A). Thereby, the impact load received from the blast furnace charge A can be relieved.

  Further, by welding the end of the impact / wear resistant plate 112 on the downstream side in the sliding direction, the welding work of the other impact / wear resistant plates 112 adjacent thereto can be facilitated. This point will be specifically described with reference to a reference example. FIG. 3 is a schematic diagram schematically showing the welding process of the reference example. The welding process proceeds in the order of (A), (B), and (C).

  Referring to FIG. 3, in the state where the impact / wear plate 112 is oriented vertically and the lower end surface of the impact / wear plate 112 is in contact with the plate welding surface 121 </ b> A, The substrate portion 112A is fillet welded to the plate welding surface 121A (see FIG. 3A). The fillet welded portion is referred to as fillet welded portion 201.

  As shown in FIG. 3A, the fillet welded portion 201 protrudes from the substrate portion 112A of the impact / abrasion resistant plate 112, and this protruding portion is excised with a grinder (not shown). )reference). Next, fillet welding is performed on the plate welding surface 121A in a state where another shock / wear plate 112 is pressed against the end face of the substrate portion 112A of the welded shock / wear plate 112 (FIG. 3A). reference).

  Thus, in the process of the reference example, it is necessary to partially cut the fillet weld portion once welded to the plate welding surface 121A. For this reason, work efficiency is reduced, and it takes time to replace the liner 110. On the other hand, in the present embodiment, the step of deleting the fillet welded portion can be omitted, so that the manufacturing efficiency of the liner 110 can be improved. Needless to say, the configuration of the reference example is included in the present invention.

  As described in the background art, a great effort is required to increase the thickness of the overlay weld layer. As a method for reducing this labor, in this embodiment, the fixed angle of the shock / wear resistant plate 112 is set so that the substrate 112A and the overlay weld layer 112B are aligned in the sliding direction of the blast furnace charge A. Thereby, since the depth (depth in the direction orthogonal to the sliding surface) of the build-up weld layer 112B is increased, impact resistance and wear resistance can be improved.

  Further, when welding the build-up weld layer 112B, it is not necessary to increase the thickness of the build-up weld layer 112B (thickness in the thickness direction of the shock and wear resistant plate 112), thereby simplifying the build-up welding work. can do. Furthermore, the liner 110 having a thick build-up weld layer can be obtained simply by performing fillet welding with the impact / wear resistant plate 112 in a substantially vertical orientation. Thereby, high impact resistance and wear resistance can be obtained while simplifying the work process.

  The impact / abrasion resistant plate 112 may be manufactured by cutting it out from a single elongated plate, or may be manufactured individually.

  In the sliding direction of the blast furnace charge A, the shock and wear resistant plates 112 adjacent to each other are slightly separated without being joined. Here, in the adjacent shock / wear plate 112, the weld weld layer 112B of the shock / wear plate 112 located on the downstream side and the substrate 112A of the shock / wear plate 112 located on the upstream side are provided. In the case of joining, since the thermal expansion coefficients of the substrate 112A and the build-up weld layer 112B are different from each other, there is a possibility that a crack or the like may occur in the joined portion. On the other hand, in this embodiment, since the adjacent shock / wear resistant plates 112 are not joined, such a problem does not occur.

  Further, when the shock / wear plate 112 is thermally expanded, a pressing load is applied to another shock / wear plate 112 adjacent thereto. The impact and wear resistant plate 112 that has been subjected to the indentation load slightly swings around the fillet welded portion 201, and therefore the indentation load can be reduced. The adjacent impact / wear resistant plates 112 may be brought into contact with each other without being joined to each other.

Here, as shown in FIG. 4, it is preferable to set θ ≦ 30 °, where θ is the angle of the shock / wear resistant plate 112 with respect to the plate welding surface 121A. By setting θ ≦ 30 °, the thickness of the build-up weld layer 112B (thickness in the normal direction of the plate weld surface 121A) is increased, and impact resistance and wear resistance can be further enhanced. The angle θ corresponds to the “angle of the plate with respect to the fixed surface” described in claim 2 .

  The end plate 131 is attached to the end surface on the downstream side of the bottom plate portion 121. A recess 131A is formed on one end surface of the end plate 131 in the sliding direction of the blast furnace charge A. One end of the biasing spring 141 is fixed to the recess 131A. The other end of the biasing spring 141 is in contact with the substrate 112A of the shock / wear resistant plate 112. The biasing spring 141 is charged in the compression direction.

  When the blast furnace charge A supplied to the liner 110 collides with the shock / wear plate 112, the shock / wear plate 112 swings slightly in the clockwise direction around the fillet weld 201. At this time, since the impact / wear plate 112 is pushed back in the clockwise direction by the biasing spring 141, the load applied to the shock / wear plate 112 can be reduced.

  In the above-described embodiment, the swivel chute 11 provided at the top of the blast furnace has been described. However, the present invention is not limited to this and can be applied to other transfer structures. Here, as other transport structures, a structure that requires a long life that is difficult to replace, such as a secondary material charging chute provided in the converter factory, a blind liner under the devil crusher provided in the sintering factory, etc. It can be illustrated.

It is the schematic of a blast furnace top part. It is the schematic of the liner of a turning chute. It is the schematic diagram which showed typically the welding process of the reference example. It is an enlarged view of an impact-resistant and abrasion-resistant plate, and shows the mounting angle with respect to the plate welding surface. It is the schematic which showed the fish-plate type protective liner. It is the schematic of a smooth liner. It is the schematic which illustrated improvement of the smooth liner. It is the schematic which illustrated the stone liner type protective liner. It is the schematic of the protective liner of patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blast furnace 11 Turning chute 12 Vertical chute 13 Inclination adjustment shaft part 14 Hopper part 15 Gate 16 Bunker 17 Gate rotating shaft 110 Liner 111 Sliding part 112A Substrate 112B Overlay welding layer 121 Bottom plate part

Claims (7)

By arranging a plurality of plates side by side on a fixed surface, a transport structure that forms a transport path for massive minerals,
Each of the plates has a substrate and a weld layer welded on the substrate, and the substrate and the weld layer in each of the plates are alternately arranged in the transport direction of the massive mineral , Out of each of the plates, the downstream end in the transport direction is fillet welded to the fixed surface, and the upstream end is separated from the fixed surface . Structure. The transport structure according to claim 1 , wherein an angle of the plate with respect to the fixed surface is 30 degrees or less. In each said plate, the said welding layer is located in the upstream of the said conveyance direction rather than the said board | substrate, The structure for conveyance of Claim 1 or 2 characterized by the above-mentioned. Any one of claims 1 to 3, characterized in that it has a biasing means to said plate which is located on the most downstream of the transport direction among the plurality of plates, for urging the upstream side in the transport direction The transport structure described in 1. The substrate, carrying structure according to any one of claims 1 to 4, wherein the high coefficient of thermal expansion than the overlay welding layer. The plate conveying structure according to any one of claims 1 to 5, characterized in that spaced apart or in contact without being joined together adjacent to each other in the transport direction. The said structure for conveyance is a distribution chute arrange | positioned at the furnace top part of a blast furnace, The structure for conveyance as described in any one of the Claims 1 thru | or 6 characterized by the above-mentioned.

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