JP2014050852A - Apparatus and method for joining metal plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably heat and join the fore-and-aft ends of a plurality of metal plates with each other over the all plate width without being affected by oxides containing an easily oxidizable alloying element, and as a result, to suppress a break of a joining portion between metal plates.SOLUTION: A metal plate joining apparatus 10 as an embodiment of the invention includes an electric welding unit 16, pressing units 17, 18 and a control unit 19. The electric welding unit 16 feeds welding materials to the place between the fore-and-aft ends of a preceding plate 4 and a succeeding plate 5 after induction heating. The pressing units 17, 18 sandwich and press the welding materials between the fore-and-aft ends by the pressing of this fore-and-aft ends. The electric welding unit 16 heats and melts the welding materials by passing an electric current to the welding materials sandwiched in this way. The control unit 19 controls the pressing units 17, 18 so as to press and join the fore-and-aft ends after the induction heating, while sandwiching and pressing the welding materials between the fore-and-aft ends, during a period when at least the welding materials are heated and melted.

Description

  The present invention relates to a metal plate joining apparatus and a metal plate joining method for joining a plurality of metal plates.

  Conventionally, in a hot rolling line for producing a hot-rolled steel sheet by finish rolling a plate-like steel material (hereinafter referred to as a steel sheet) obtained by rough rolling of a steel slab, each steel sheet after rough rolling is finish-rolled. Heat bonding is sequentially performed before. In general, in the above-described heat bonding between steel plates, a tail end portion of a steel plate (hereinafter referred to as a preceding plate) that precedes from a rough rolling facility of a hot rolling line to a finishing rolling facility, and the preceding plate follow. A steel plate (hereinafter referred to as a trailing plate) is heated and pressed. As a result, the tail end portion of the preceding plate and the leading end portion of the succeeding plate (hereinafter, the tail end portion and the leading end portion are collectively referred to as the leading end portion) are heat-bonded. By sequentially performing heating joining between the leading end portions of the preceding plate and the following plate on the plurality of steel plates after rough rolling, the plurality of steel plates are processed into a continuous series of steel plates. The This series of steel plates is useful for continuous hot rolling (endless rolling) in which finish rolling of the steel plates is continuously performed without breaks.

  Moreover, as a heating method of the steel plate in the above-described heat bonding, for example, a transverse induction heating method is used. In the transverse induction heating method, an electric current is supplied to a pair of coils facing each other with a steel plate sandwiched in the thickness direction (hereinafter referred to as the plate thickness direction), thereby alternating the steel plate through the plate thickness direction. A magnetic field is generated, and an alternating magnetic field in the thickness direction is applied to the steel plate. As a result, an eddy current is induced in the steel sheet, and the steel sheet is heated by Joule heat derived from the eddy current.

  In addition, as a conventional technique related to heat joining of steel plates in a hot rolling line, for example, joining by pressing the tail end portion of the preceding plate and the tip portion of the succeeding plate by induction heating by a transverse induction heating method. There is a technology (see Patent Document 1). The contact area between the tail end of the preceding plate and the tip of the succeeding board is a partial area in the width direction of the steel sheet (hereinafter referred to as the plate width direction), and the electrode is in contact with the contact area between the leading ends. There is also a method of joining the tail end portion of the preceding plate and the leading end portion of the succeeding plate by energization through (see Patent Document 2). Alternatively, at least one steel type of the preceding plate and the following plate is a steel type containing an alloy element that generates an oxide having a melting point higher than that of the steel, and the leading plate and the following plate are obtained by a transverse induction heating method. A region having a length of 20% or less of the thickness of the steel plate is heated to a temperature higher than the liquidus temperature of the steel plate from each joint surface, and the pressing amount between the preceding plate and the subsequent plate is set to 50% or more of the thickness of the steel plate. There is also a joining method (see Patent Document 3).

JP 62-234679 A JP-A-7-124606 JP 2000-271606 A

  In recent years, there has been a demand for higher tensile strength of steel sheets. Accordingly, steel materials obtained by adding alloy elements such as Si, Mn, Cr and the like in a predetermined amount or more to steel, so-called alloy steels, are hot-rolled steel sheets. It is used as a steel grade. In addition, as the tensile strength of steel sheets increases, the content of alloy elements in alloy steel tends to increase. When such steel plates of alloy steel are heat-joined, an oxide containing an easily oxidizable alloy element intervenes at the joining interface between the steel plates. Due to this oxide, the joining strength between the leading and trailing edges of the preceding and succeeding plates is remarkably reduced, and as a result, the joining portion between the steel plates is often broken during finish rolling. In addition, in the prior art described in Patent Document 3 described above, in order to discharge such an alloy element-containing oxide from the bonding interface between the steel plates, the heating temperature and heating time of the bonding interface are set for each steel type to be bonded. It is necessary to manage strictly. For this reason, for each of a plurality of steel plates sequentially conveyed on the hot rolling line, the temperature condition and time condition of the heat bonding must be changed for each steel type, and a great deal of labor is required for the heat bonding between the steel plates. Cost.

  Moreover, in the prior art described in Patent Document 1 described above, even if an eddy current is induced in the leading end portion of the metal plate by an alternating magnetic field penetrating the metal plate such as alloy steel in the plate thickness direction, the energization path Due to the nature of the eddy current, the eddy current hardly flows at both ends in the plate width direction of the metal plate, particularly at both corners of the leading end. For this reason, it is difficult to sufficiently heat both corners of the leading end by Joule heat derived from eddy current. Due to this, even if the center side of the leading end is heated to a temperature suitable for joining, in most cases, both corners of the leading end do not rise to a temperature suitable for joining. As a result, it is difficult to reliably heat-join the leading end portions of the metal plates over the entire plate width. Such a problem occurs in the same manner because current does not easily flow in both corners of the leading end even when energized through electrodes as exemplified in Patent Document 2.

  In addition, as mentioned above, when the heat joining between the leading ends of the metal plates is insufficient, the strength of each joined portion of a series of metal plates in which a plurality of metal plates are connected in a band shape by this heat joining is insufficient. It becomes. This is highly likely to cause breakage of the joint between the metal plates in a series of metal plate processing steps such as endless rolling. Specifically, in the finish rolling step performed after the above-described heat joining, the metal plate is often broken at the joining portion, and finish rolling of the metal plate is often impossible. That is, it is extremely important to reliably heat and bond the leading ends of the metal plates in order to efficiently perform a series of metal plate processing steps such as endless rolling.

  The present invention has been made in view of the above circumstances, and without affecting the oxide containing an easily oxidizable alloy element, the leading end portions of a plurality of metal plates are made to have the entire plate width. As a result, the metal plate joining apparatus and the metal that can suppress the breakage of the joint portion between the metal plates, even in the case of a metal plate made of an alloy steel containing an easily oxidizable alloy element. An object is to provide a plate joining method.

  In order to solve the above-described problems and achieve the object, a metal plate joining apparatus according to the present invention includes a tail end portion of a preceding metal plate that precedes a plurality of metal plates conveyed along a conveyance path, In the metal plate joining apparatus for inductively heating the tip end portion of the succeeding metal plate following the preceding metal plate, and heating and joining the tail end portion and the tip portion after induction heating, the tail end after induction heating Welding material feeding section for feeding welding material between both ends in the plate width direction of the plate and both ends in the plate width direction of the tip after induction heating, and the tail end portion and induction heating after induction heating The pressing portion that presses the rear end portion and presses the welding material between the both end portions in the plate width direction, and the press portion that is pressed between the both end portions in the plate width direction. A heating section that heats and melts the welding material by passing an electric current through the welding material; and at least the heating section heats and melts the welding material. The pressing is performed so as to press and join the tail end portion after induction heating and the tip end portion after induction heating while sandwiching the welding material between both ends of the both sides in the plate width direction. And a control unit for controlling the unit.

  In the metal plate joining apparatus according to the present invention, in the above invention, the heating unit applies an alternating magnetic field penetrating the metal plate in the thickness direction of the metal plate to the tail end portion and the tip end portion. And it is an induction heating part which induction-heats the said welding material clamped between each of both said board width direction both ends.

  Moreover, in the metal plate joining apparatus according to the present invention, in the above invention, the induction heating unit induction-heats the tail end and the front end facing each other while being separated from each other by applying the alternating magnetic field. It is characterized by.

  In the metal plate joining apparatus according to the present invention, in the above invention, the control unit controls the induction heating unit so as to stop induction heating of the tail end portion and the tip end portion in a state of being separated from each other. Then, during the induction heating stop period, the tail end portion after induction heating and the tip end portion after induction heating are pressed so that the welding material is sandwiched between the both ends in the plate width direction. The induction heating unit is controlled so as to inductively heat the welding material by applying the alternating magnetic field to the tail end portion and the tip end portion that are connected to each other via the welding material. It is characterized by controlling.

  Further, in the metal plate joining apparatus according to the present invention, in the above invention, the heating unit uses a plurality of electrodes, and a current is supplied to the welding material sandwiched between both the both ends in the plate width direction. It is an electric current heating part which carries out electric current heating of the said welding material.

  In the metal plate joining apparatus according to the present invention, in the above invention, the metal plate is an alloy steel containing silicon of 0.2 [mass%] or more and 3.5 [mass%] or less, The welding material is low carbon steel.

  Further, the metal plate joining method according to the present invention includes a tail end portion of a preceding preceding metal plate among a plurality of metal plates conveyed along a conveying path, and a succeeding metal plate following the preceding metal plate. In the metal plate joining method in which the tip end portion is induction-heated and the tail end portion after the induction heating and the tip end portion are heat-joined, both end portions in the plate width direction of the tail end portion after the induction heating and after the induction heating A welding material feeding step for feeding a welding material between each end portion in the plate width direction of the tip portion, and pressing the tail end portion after induction heating and the tip portion after induction heating, A welding material clamping step for clamping the welding material between each of the both ends in the plate width direction, and applying a current to the welding material while clamping the welding material between each of the both ends in the plate width direction. And a heating and melting step for heating and melting the welding material.

  In the metal plate joining method according to the present invention, in the above invention, in the heating and melting step, an alternating magnetic field penetrating the metal plate in the thickness direction of the metal plate is applied to the tail end portion and the tip end portion. It applies, and the said welding material clamped between each of the both said board width direction both ends is induction-heated, It is characterized by the above-mentioned.

  Further, the metal plate joining method according to the present invention further includes an induction heating step of inductively heating the tail end portion and the tip end portion facing each other in a state of being separated from each other by application of the alternating magnetic field in the above invention, In the welding material feeding step, the welding material is fed between both ends of the plate width direction after the induction heating in the induction heating step.

  The metal plate joining method according to the present invention further includes an induction heating stop step for stopping induction heating of the tail end portion and the tip end portion in a state of being separated from each other in the above invention, In the induction heating stop period, the tail end portion after induction heating and the tip end portion after induction heating are pressed, and the welding material is sandwiched between the both end portions in the plate width direction. The heating and melting step applies the alternating magnetic field to the tail end portion and the tip end portion connected to each other via the welding material to inductively heat the welding material.

  Further, in the metal plate joining method according to the present invention, in the above invention, the heating and melting step uses a plurality of electrodes, and current is applied to the welding material sandwiched between both ends in the plate width direction. And the welding material is heated by energization.

  Further, in the metal plate joining method according to the present invention, in the above invention, an alloy steel containing silicon of 0.2 [mass%] or more and 3.5 [mass%] or less is used as the metal plate, A low carbon steel is used as the welding material.

  According to the present invention, it is possible to reliably heat-join the leading end portions of a plurality of metal plates across the entire plate width without being affected by the oxide containing the easily oxidizable alloy element. Even if it is the case of the metal plate of alloy steel containing an easily oxidizable alloy element, there exists an effect that the fracture | rupture of the junction part of metal plates can be suppressed.

FIG. 1 is a block diagram illustrating a configuration example of a metal plate joining apparatus according to a first embodiment of the present invention. FIG. 2 is a view of the induction heating unit shown in FIG. 1 as viewed from the conveying direction of the steel plate. FIG. 3 is a schematic diagram illustrating a configuration example of the electric welding portion of the metal plate joining apparatus according to the first embodiment. FIG. 4 is a flowchart showing an example of the metal plate joining method according to the first embodiment. FIG. 5 is a schematic view showing a state in which the tail end portion of the preceding plate and the tip end portion of the succeeding plate that are separated from each other are induction-heated. FIG. 6 is a schematic diagram showing a state in which the welding material sandwiched between the leading end portions of the preceding and succeeding plates after induction heating is energized and heated. FIG. 7 is a schematic diagram illustrating a state in which the leading end portions of the preceding plate and the succeeding plate after the welding material is heated and melted are joined to each other. FIG. 8 is a block diagram illustrating a configuration example of the metal plate joining apparatus according to the second embodiment of the present invention. FIG. 9 is a schematic diagram illustrating a configuration example of a welding material feeding unit of the metal plate joining apparatus according to the second embodiment. FIG. 10 is a schematic diagram for explaining the heat joining between the leading end portions of the preceding and succeeding plates in the second embodiment. FIG. 11 is a schematic diagram showing another example of the arrangement of a plurality of electrodes used for energization heating of the welding material. FIG. 12 is a schematic diagram illustrating another example of the welding material feeding mode.

  Exemplary embodiments of a metal plate joining apparatus and a metal plate joining method according to the present invention will be explained below in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiment.

(Embodiment 1)
FIG. 1 is a block diagram illustrating a configuration example of a metal plate joining apparatus according to a first embodiment of the present invention. FIG. 1 shows a part of a hot rolling line in which the metal plate joining apparatus 10 according to the first embodiment is installed. Hereinafter, with reference to FIG. 1, first, a schematic configuration of a hot rolling line to which the metal plate bonding apparatus 10 is applied will be described, and then the configuration of the metal plate bonding apparatus 10 will be described.

  As shown in FIG. 1, the metal plate joining apparatus 10 according to the first embodiment is installed between a rough rolling part 1 and a finish rolling part 2 of a hot rolling line. Specifically, the rough rolling unit 1, the metal plate joining apparatus 10, and the finish rolling unit 2 are arranged along the conveyance direction of the steel plate in the conveyance path 3 of the hot rolling line (see the broken line arrow in FIG. 1). Is done. In addition, the conveyance path | route 3 is implement | achieved using several conveyance rolls.

  The rough rolling section 1 obtains a steel plate by roughly rolling a steel slab heated by a heating furnace (not shown) into a plate shape. The steel sheet after the rough rolling is transported from the rough rolling unit 1 to the metal plate joining apparatus 10 along the transport path 3. The metal plate joining apparatus 10 sequentially induces and heats steel plates by a transverse induction heating method, and heat-joins the opposing ends (leading ends) of each steel plate after induction heating using welding materials. . Thereby, the metal plate joining apparatus 10 obtains a series of steel plates in which a plurality of steel plates are integrated in a strip shape. Such a series of steel plates is conveyed from the metal plate joining apparatus 10 to the finishing rolling unit 2 along the conveyance path 3.

  The finish rolling unit 2 finish-rolls a series of steel plates joined in a strip shape by the metal plate joining apparatus 10 as described above, and obtains a hot-rolled steel plate having a desired thickness. In this case, the finish rolling unit 2 performs endless rolling in which a plurality of steel plates forming a series of steel plates are continuously finish-rolled. By performing this endless rolling, the finish rolling unit 2 can finish and roll a plurality of steel plates continuously without breaks, and stagnates the steel plate before finish rolling on the entry side of the finishing rolling unit 2 during rolling operation. The situation can be prevented. As a result, the finish rolling unit 2 can efficiently finish and roll a plurality of steel plates. In addition, the hot-rolled steel sheet after finish rolling is sent out from the exit side of the finish rolling unit 2, and thereafter, various treatments by a hot rolling line are appropriately performed.

  Below, the structure of the metal plate joining apparatus 10 concerning this Embodiment 1 is demonstrated. The metal plate joining device 10 is a device that heat-joins a plurality of steel plates transported along the transport path 3, and as shown in FIG. 1, a cutting unit 11, an induction heating unit 12, an electric welding unit 16, , Pressing portions 17 and 18 and a control unit 19. Moreover, the cutting part 11 is arrange | positioned in the back | latter stage of the rough rolling part 1 along the conveyance path | route 3 of the hot rolling line shown in FIG. 1, and the press part 17, the induction heating part 12, and electricity are arranged in the back | latter stage of the cutting part 11. A welded portion 16 and a pressing portion 18 are disposed.

  The cutting part 11 cuts and forms the leading end of each steel plate. Specifically, the cutting unit 11 includes cutting rollers 11a and 11b provided with a plurality of blades 11c. As shown in FIG. 1, the cutting rollers 11 a and 11 b are paired by being arranged in the plate thickness direction of the steel plate with the conveyance path 3 interposed therebetween. Further, on the outer peripheral surfaces of the cutting rollers 11a and 11b, the blades 11c are arranged point-symmetrically with respect to the rotation axis of the cutting rollers 11a and 11b. The cutting unit 11 sandwiches the leading end of the steel plate in the thickness direction by the blades 11c of the cutting rollers 11a and 11b while rotating the cutting rollers 11a and 11b in the outer circumferential direction. Thereby, the cutting part 11 cut | disconnects (shears) the tail end part of a steel plate in the plate | board thickness direction. The cutting part 11 repeats the above-described cutting process on the leading end part of each steel sheet that is sequentially conveyed, thereby forming the shapes in which the opposing surfaces of the leading end parts of each steel sheet can be engaged with each other. Mold. The steel plates whose leading end portions are cut and formed in this way are sequentially conveyed from the cutting portion 11 to the induction heating portion 12 side along the conveying path 3.

  The induction heating unit 12 induction-heats the object to be heated by a transverse induction heating method. FIG. 2 is a view of the induction heating unit shown in FIG. 1 as viewed from the conveying direction of the steel plate. As shown in FIGS. 1 and 2, the induction heating unit 12 includes coils 13 a and 13 b, a core 14, and a power source 15. The coils 13a and 13b are arranged so as to face each other in the plate thickness direction of the steel sheet with the conveyance path 3 interposed therebetween, and to make the respective coil axis directions substantially the same direction. The coils 13 a and 13 b are connected in series with the power supply 15. Almost the same amount of alternating current is supplied from the power supply 15 to each of the coils 13a and 13b. The core 14 is a C-type core around which the coils 13a and 13b are wound as shown in FIG. The core 14 is formed using a magnetic material such as an electromagnetic steel plate, and reinforces and arranges the magnetic flux of an alternating magnetic field generated by the wound coils 13a and 13b. In addition, the coils 13a and 13b wound around the core 14 are arranged to face each other as described above to form the coil pair 13. The power supply 15 supplies a high frequency or medium frequency alternating current to the coil pair 13.

  In the induction heating unit 12 having such a configuration, the coils 13 a and 13 b of the coil pair 13 generate an alternating magnetic field penetrating the steel plate in the thickness direction in accordance with the alternating current supplied from the power source 15. The induction heating unit 12 applies an alternating magnetic field generated by the coil pair 13 to the leading ends of the leading plate 4 and the trailing plate 5 as indicated by solid arrows in FIG. In addition, about the board width direction of a steel plate, as shown in FIG. 2, the size of the coil pair 13, ie, each size of the coils 13a and 13b, is set to the board width of the leading end part of the preceding board 4 and the succeeding board 5. The leading ends of the leading plate 4 and the trailing plate 5 are inside the coil pair 13. For this reason, the alternating magnetic field by the coil pair 13 is applied over the entire plate width of the leading end portions of the leading plate 4 and the trailing plate 5. The induction heating unit 12 thus induces eddy currents at the leading ends of the leading plate 4 and the trailing plate 5 by applying an alternating magnetic field to the leading ends of the leading plate 4 and the trailing plate 5 in this way. The leading ends of the leading plate 4 and the trailing plate 5 are induction-heated by Joule heat derived from this eddy current. The induction heating unit 12 induction-heats the leading end as described above each time the leading end of the leading plate 4 and the trailing plate 5 is conveyed along the conveying path 3.

  Here, the preceding plate 4 and the following plate 5 described above are two of the plurality of steel plates conveyed along the conveyance path 3. The preceding plate 4 is a steel plate that precedes the transport path 3, and the trailing plate 5 is a steel plate that follows the preceding plate 4. As shown in FIG. 1, the tail end portion of the preceding plate 4 and the tip end portion of the succeeding plate 5 face each other in the conveying direction of the steel plate. On the other hand, the steel types of the leading plate 4 and the trailing plate 5 are not particularly limited, but in the first embodiment, the leading plate 4 and the trailing plate 5 are, for example, silicon (Si), manganese (Mn) chromium (Cr). Alloy steel containing a predetermined amount or more of an easily oxidizable alloy element such as titanium (Ti) or aluminum (Al) may be used.

  The electric welding portion 16 joins the leading end portions of the leading plate 4 and the trailing plate 5 by electric welding. FIG. 3 is a schematic diagram illustrating a configuration example of the electric welding portion of the metal plate joining apparatus according to the first embodiment. Note that FIG. 3 shows the configuration of the electric weld 16 viewed from the thickness direction of the steel plate. As shown in FIG. 3, the electric welding unit 16 includes welding material feeding rollers 16 a and 16 b, electrodes P <b> 1 to P <b> 6, and welding power sources 16 e to 16 g.

  The welding material feed rollers 16a and 16b are respectively disposed at both end portions in the plate width direction with the leading end portions of the leading plate 4 and the trailing plate 5 interposed therebetween. As shown in FIG. 3, the welding material feeding roller 16 a is rotated so that the welding material is interposed between the plate width end portions 4 a and 5 a of the leading end portions of the leading plate 4 and the trailing plate 5. 16c is sent. The welding material feeding roller 16b rotates to feed the welding material 16d between the other plate width end portions 4b, 5b of the leading end portions of the leading plate 4 and the trailing plate 5. The welding material feed rollers 16a and 16b are rotated by the action of a drive mechanism (not shown). Such welding material feeding rollers 16a and 16b are provided with the plate width end portions 4a and 4b at the tail end portion of the preceding plate 4 after induction heating by the induction heating unit 12 described above, and the subsequent after the same induction heating. A welding material feeding section for feeding welding materials 16c and 16d between the plate width end portions 5a and 5b at the front end of the plate 5 is configured.

  Of the plurality of electrodes P1 to P6, the electrodes P1 and P2 are electrically connected to the welding power source 16e. The electrode P1 is disposed in the vicinity of the plate width end portion 5a in the front end portion of the trailing plate 5, and the electrode P2 is disposed in the vicinity of the plate width end portion 4a in the tail end portion of the preceding plate 4. The welding power source 16e supplies power to the leading end portions of the leading plate 4 and the trailing plate 5 through the pair of electrodes P1 and P2, and is welded between the plate width end portions 4a and 5a. Through this, a current is passed between the leading ends. Electrodes P3 and P4 are electrically connected to welding power source 16f. The electrode P3 is disposed in the vicinity of the plate width end portion 5b in the distal end portion of the trailing plate 5, and the electrode P4 is disposed in the vicinity of the plate width end portion 4b in the tail end portion of the preceding plate 4. The welding power source 16f feeds power to the leading end portions of the leading plate 4 and the trailing plate 5 via the pair of electrodes P3 and P4, and the welding material 16d is sandwiched between the plate width end portions 4b and 5b. Through this, a current is passed between the leading ends. Electrodes P5 and P6 are electrically connected to welding power source 16g. The electrode P5 is disposed in the vicinity of the intermediate portion 5c in the width direction of the trailing plate 5 in the front end portion thereof. The electrode P6 is disposed in the vicinity of the intermediate portion 4c in the plate width direction of the tail end portion of the preceding plate 4. The welding power source 16g supplies power to the leading end portions of the leading plate 4 and the trailing plate 5 through the pair of electrodes P5 and P6, and through the welding materials 16c and 16d in a clamped state as described above, A current is passed between the parts. The welding power sources 16e to 16g as described above use a plurality of electrodes P1 to P6, and between the plate width end portions 4a and 4b and the plate width end portions 5a and 5b of both the leading plate 4 and the trailing plate 5. An electric current is passed through the clamped welding materials 16c and 16d to heat and heat the welding materials 16c and 16d, thereby forming an electric heating section that heats and melts the welding materials 16c and 16d. In addition, the current which flows into the welding materials 16c and 16d by such an energization heating part may be an alternating current or a direct current.

  Here, the plate width end portions 4a and 4b of the preceding plate 4 are both ends of the tail end portion of the preceding plate 4 in the plate width direction, and are portions including both corners of the tail end portion and the vicinity thereof. The plate width end portions 5a and 5b of the trailing plate 5 are both ends of the leading end portion of the trailing plate 5 in the plate width direction and include both corners of the leading end portion and the vicinity thereof. As shown in FIG. 3, the intermediate portion 4 c of the preceding plate 4 is a portion sandwiched between the two plate width end portions 4 a and 4 b of the tail end portion of the preceding plate 4. The intermediate portion 5 c of the trailing plate 5 is a portion sandwiched between both plate width end portions 5 a and 5 b of the leading end portion of the trailing plate 5.

  On the other hand, the welding materials 16c and 16d may have their metal types set corresponding to the steel types of the leading plate 4 and the trailing plate 5, but are different from the leading plate 4 and the trailing plate 5, for example, the leading plate. It is desirable to use a low alloy steel material that is the same alloy element as the alloy element contained in the plate 4 and the succeeding plate 5 and does not contain anything other than carbon (C). In particular, when the leading plate 4 and the trailing plate 5 are alloys containing Si of 0.2 [mass%] or more and 3.5 [mass%] or less, the welding materials 16c and 16d do not contain Si. A low alloy steel such as low carbon steel is desirable. Further, the shape and dimensions of the welding materials 16c and 16d are determined so that the preceding plate 4 is sandwiched between the plate width end portions 4a and 4b of the preceding plate 4 and the plate width end portions 5a and 5b of the succeeding plate 5. It is desirable that the contact area between the facing end surface of the leading end portion of 4 and the trailing plate 5 and the welding materials 16c and 16d is set to be as small as possible. For example, the thicknesses of the welding materials 16c and 16d may be set as compared with the thicknesses of the preceding plate 4 and the following plate 5, and the cross-sectional shapes of the welding materials 16c and 16d are circular, elliptical, and rectangular. You may make it.

  The pressing portions 17 and 18 press the leading end portions of the leading plate 4 and the trailing plate 5. Specifically, the pressing parts 17 and 18 are each realized using a clamp mechanism, a pressing mechanism, and the like. As shown in FIG. 1, the pressing unit 17 is disposed on the entry side of the induction heating unit 12, and the pressing unit 18 is disposed on the exit side of the induction heating unit 12. The pressing portion 17 clamps the trailing plate 5, and the pressing portion 18 clamps the preceding plate 4. Further, the pressing portion 17 presses the leading end portion of the succeeding plate 5 that is induction-heated by the induction heating portion 12 toward the tail end portion of the preceding plate 4 as indicated by a thick arrow in FIG. In parallel with this, the pressing unit 18 presses the tail end portion of the preceding plate 4 induction-heated by the induction heating unit 12 toward the tip end portion of the succeeding plate 5 as indicated by the thick arrow in FIG. To do. That is, the pressing portions 17 and 18 press the tail end portion of the preceding plate 4 after induction heating and the tip end portion of the succeeding plate 5 after induction heating. As a result, the pressing portions 17 and 18 are welded between the both plate width end portions 4a and 4b of the preceding plate 4 after induction heating and the both plate width end portions 5a and 5b of the succeeding plate after induction heating. 16c and 16d (see FIG. 3) are clamped. The pressing portions 17 and 18 press and join the leading end portions of the preceding plate 4 and the succeeding plate 5 after induction heating after the above-described welding materials 16c and 16d are heated and melted. The pressing units 17 and 18 sequentially perform the above-described pressing process on the plurality of steel plates conveyed along the conveyance path 3.

  The control unit 19 controls the cutting unit 11, the induction heating unit 12, the electric welding unit 16, and the pressing units 17 and 18. Specifically, the control unit 19 grasps the position of each steel plate in the transport path 3 based on the transport information (transport speed or the like) of each steel plate on the transport path 3. The control unit 19 controls the operation timings of the cutting unit 11, the induction heating unit 12, the electric welding unit 16, and the pressing units 17 and 18 based on the grasped position of each steel plate.

  For example, the control unit 19 controls the cutting unit 11 to cut and form the tail end of the steel plate such as the preceding plate 4 to the cutting unit 11 at the timing when the tail end of the steel plate is conveyed to the cutting unit 11. At the timing when the tip of the steel plate is conveyed to the cutting part 11, the cutting part 11 is controlled so as to cut and form the tip. On the other hand, the control unit 19 clamps the leading plate 4 at the timing when the leading plate 4 and the trailing end of the trailing plate 5 are located inside the coil pair 13 (see FIG. 2) of the induction heating unit 12. The pressing portion 17 is controlled so as to control the pressing portion 18 and clamp the trailing plate 5. The control unit 19 controls the induction heating unit 12 so as to induction-heat the tail end portion of the preceding plate 4 and the tip end portion of the succeeding plate 5 which are fixed in position by the clamping operation and are opposed to each other in a separated state. Further, the control unit 19 sends the welding materials 16c and 16d between the plate width end portions 4a and 4b and the plate width end portions 5a and 5b of both the preceding plate 4 and the succeeding plate 5 after the induction heating. The welding material feeding part of the electric welding part 16 is controlled so as to feed. In this case, the control unit 18 controls the driving mechanism (not shown) of the electric welding unit 16 to control the rotation of the welding material feeding rollers 16a and 16b, and the control of the welding material feeding rollers 16a and 16b. The feed timing and feed amount of the welding materials 16c and 16d are controlled.

  Moreover, the control part 19 controls each operation | movement of the induction heating part 12, the electric welding part 16, and the press parts 17 and 18 based on time information. Specifically, the control unit 19 stops the induction heating at the timing when the induction heating of the tail end portion of the preceding plate 4 and the tip end portion of the succeeding plate 5 that are separated from each other is performed for a predetermined time. Thus, the induction heating unit 12 is controlled. Next, the control unit 19 presses the tail end portion of the preceding plate 4 after the induction heating and the tip end portion of the succeeding plate 5 after the induction heating during the induction heating stop period, and the plate width end portions 4a and 4b. The pressing portions 17 and 18 are controlled so that the welding materials 16c and 16d are sandwiched between the plate width end portions 5a and 5b. The control part 19 is the welding material 16c, 16d at the timing when the tail end part of the preceding board 4 and the front-end | tip part of the succeeding board 5 were mutually connected via welding material 16c, 16d by the press of the press parts 17 and 18. The energization heating part of the electric welding part 16 is controlled so as to be energized and heated. In this case, the control unit 19 controls the welding power sources 16e to 16g so as to continue the energization heating of the welding materials 16c and 16d for a predetermined time. In parallel with this, the control part 19 is the welding material 16c between each of the plate width end part 4a, 4b and the plate width end part 5a, 5b in the period when the electric welding part 16 heat-melts the welding material 16c, 16d. , 16d are pressed, and the pressing portions 17, 18 are controlled so as to press and join the tail end portion of the preceding plate 4 after induction heating and the tip end portion of the succeeding plate 5 after induction heating. In this case, the control unit 19 continues to press the tail end portion of the leading plate 4 and the leading end portion of the trailing plate 5 for a time longer than the duration of the energization heating of the welding materials 16c and 16d by the electric welding portion 16. The pressing parts 17 and 18 are controlled.

  Further, the control unit 19 controls the induction heating strength of the leading end portions of the leading plate 4 and the trailing plate 5 by the induction heating unit 12 and the energization heating strength of the welding materials 16 c and 16 d by the electric welding unit 16. Specifically, the control unit 19 controls the power source 15 so as to increase or decrease the supply amount of the alternating current to the coil pair 13 (coils 13 a and 13 b) of the induction heating unit 12. 13 controls the strength of the alternating magnetic field. As a result, the control unit 19 controls the strength of the eddy currents induced at the leading ends of the leading plate 4 and the trailing plate 5, and through the control of the eddy currents, the leading end of the leading plate 4 and the trailing plate 5. Controls the induction heating intensity at the edges. On the other hand, the control unit 19 controls the welding power sources 16e to 16g so as to increase or decrease the amount of power supplied to the electrodes P1 to P6 of the electric welding unit 16, and the energization of the welding materials 16c and 16d is performed through the control of the welding power sources 16e to 16g. Control the heating intensity.

  Below, the metal plate joining method concerning Embodiment 1 of this invention is demonstrated. FIG. 4 is a flowchart showing an example of the metal plate joining method according to the first embodiment. FIG. 5 is a schematic view showing a state in which the tail end portion of the preceding plate and the tip end portion of the succeeding plate that are separated from each other are induction-heated. FIG. 6 is a schematic diagram showing a state in which the welding material sandwiched between the leading end portions of the preceding and succeeding plates after induction heating is energized and heated. FIG. 7 is a schematic diagram illustrating a state in which the leading end portions of the preceding plate and the succeeding plate after the welding material is heated and melted are joined to each other.

  The metal plate joining apparatus 10 shown in FIG. 1 performs each processing step shown in FIG. 4 in sequence, and heat-joins the tail end portion of the preceding plate 4 and the tip portion of the succeeding plate 5. That is, in the metal plate joining method according to the first embodiment, as shown in FIG. 4, the metal plate joining device 10 first has an opposing end portion between the leading plate 4 and the trailing plate 5, that is, a leading end portion. Is formed (step S101). In step S101, the cutting unit 11 sandwiches the tail end portion of the leading plate 4 from the top and bottom by the blades 11c while rotating the cutting rollers 11a and 11b, and the tail end of the leading plate 4 by the action of the blades 11c. Cut the part in its thickness direction. Subsequently, the cutting part 11 cuts the front-end | tip part of the succeeding board 5 in the plate | board thickness direction with each blade 11c of the cutting rollers 11a and 11b similarly to the case of the tail end part of the preceding board 4. FIG. As a result, the opposing surfaces of the tail end portion of the leading plate 4 and the tip portion of the trailing plate 5 are formed into shapes that can be engaged with each other, such as a substantially linear shape.

  Next, the metal plate joining apparatus 10 induction-heats the tail end portion of the preceding plate 4 and the tip portion of the succeeding plate 5 (step S102). In step S102, the induction heating unit 12 applies an alternating magnetic field penetrating the steel plate in the thickness direction to the tail end portion of the preceding plate 4 and the tip end portion of the succeeding plate 5 in a state of being separated from each other. The tail end portion of the preceding preceding plate 4 and the tip end portion of the succeeding plate 5 are heated by induction.

  Specifically, as shown in FIG. 5, at the timing when the tail end portion of the preceding plate 4 is located inside the coil pair 13, the pressing unit 18 clamps the preceding plate 4 and fixes the position of the preceding plate 4. . In parallel with this, the pressing portion 17 moves the trailing plate 5 at a timing when the leading end of the trailing plate 5 is located inside the coil pair 13 and is separated from the tail end of the preceding plate 4 by a predetermined distance. The position of the trailing plate 5 is fixed by clamping. In this state, the coil pair 13 generates an alternating magnetic field penetrating the leading end portions of the leading plate 4 and the trailing plate 5 in the plate thickness direction in accordance with the alternating current supplied from the power supply 15. Such an alternating magnetic field is applied to the tail end portion of the leading plate 4 and the tip portion of the trailing plate 5 which are spaced apart from each other and face each other inside the coil pair 13. As a result, as shown in FIG. 5, an eddy current 8a derived from this alternating magnetic field is induced at the tail end of the preceding plate 4, and an eddy current 8b derived from this alternating magnetic field is induced at the tip of the trailing plate 5. Be guided to. The induction heating unit 12 induction-heats the tail end portion of the preceding plate 4 by Joule heat of the eddy current 8a, and induction-heats the tip portion of the trailing plate 5 by Joule heat of the eddy current 8b. The induction heating in step S102 is a first-stage heat treatment for the leading end portion of the preceding plate 4 and the succeeding plate 5 to be heat-bonded.

  Here, the tail end portion of the leading plate 4 and the tip portion of the trailing plate 5 are separated from each other inside the coil pair 13 as described above. For this reason, the eddy currents 8a and 8b are not coupled to each other and flow in a vortex shape separately from the tail end portion of the leading plate 4 and the tip portion of the trailing plate 5, as shown in FIG. In this case, the eddy currents 8a and 8b circulate in the same direction as each other, specifically, in a direction opposite to the energization direction of the alternating current flowing through the coil pair 13. Further, the eddy currents 8 a and 8 b flow in a concentrated manner in the vicinity of the opposing surfaces of the leading end portions of the leading plate 4 and the trailing plate 5. On the other hand, since the eddy current 8a circulates in a vortex shape, it does not flow to the plate width end portions 4a and 4b of the preceding plate 4. Similarly, the eddy current 8 b does not flow to the plate width end portions 5 a and 5 b at the leading end portion of the trailing plate 5. By such Joule heat of the eddy currents 8a and 8b, the induction heating unit 12 causes the intermediate part 4c in the tail end part of the preceding plate 4 and the intermediate part 5c in the tip part of the succeeding plate 5 to Heating is performed to a temperature sufficient for heat-joining, for example, to a temperature exceeding the solidus of the leading plate 4 and the trailing plate 5 (see the hatched portion in FIG. 5).

  Next, the metal plate joining apparatus 10 stops induction heating on the tail end portion of the preceding plate 4 and the tip end portion of the succeeding plate 5 that are separated from each other as described above (step S103). In step S103, the control unit 19 controls the power supply 15 so as to stop the supply of the alternating current to the coil pair 13 at the timing when the elapsed time from the start of the induction heating in step S102 reaches a predetermined time. . The control unit 19 stops the application of the alternating magnetic field to the leading end portions of the leading plate 4 and the trailing plate 5 by the coil pair 13 through the control of the power supply 15. Based on the control of the control unit 19, the induction heating unit 12 stops the induction heating in step S <b> 102, that is, induction heating for the leading end portions of the preceding plate 4 and the succeeding plate 5.

  Subsequently, the metal plate joining apparatus 10 includes a welding material 16c between both end portions in the plate width direction between the tail end portion of the preceding plate 4 after induction heating in step S102 and the tip end portion of the succeeding plate 5 after induction heating. , 16d (step S104). In step S <b> 104, the electric welding unit 16 sends the welding materials 16 c and 16 d between the leading end portions of the leading plate 4 and the trailing plate 5 after the induction heating by the induction heating unit 12 based on the control of the control unit 19. To pay. Specifically, as shown in FIGS. 3 and 6, the welding material feeding roller 16 a includes a plate width end portion 4 a of the preceding plate 4 after induction heating and a plate width end portion 5 a of the succeeding plate 5 after induction heating. In between, the welding material 16c is fed from the side of the preceding board 4 and the succeeding board 5. In parallel with this, the welding material feeding roller 16b is arranged between the plate width end 4b of the preceding plate 4 after induction heating and the plate width end 5b of the succeeding plate 5 after induction heating. The welding material 16d is fed from the side of the trailing plate 5.

  Thereafter, the metal plate joining apparatus 10 clamps the welding materials 16c and 16d between both end portions in the plate width direction of the preceding plate 4 and the succeeding plate 5 after induction heating (step S105). In step S <b> 105, the pressing parts 17, 18 are connected to the trailing edge of the leading plate 4 after induction heating and the trailing edge after induction heating during the induction heating stop period for the leading edge of the leading plate 4 and the trailing plate 5. The tip of the plate 5 is pressed. As a result, as shown in FIG. 6, the pressing portions 17 and 18 sandwich the welding material 16 c between the plate width end portion 4 a of the preceding plate 4 and the plate width end portion 5 a of the subsequent plate 5. At the same time, the welding material 16d is sandwiched between the plate width end portion 4b of the preceding plate 4 and the plate width end portion 5b of the succeeding plate 5. In this state, the leading ends of the leading plate 4 and the trailing plate 5 are partially connected to each other through the welding materials 16c and 16d.

  Next, in step S105, the metal plate joining apparatus 10 heats and melts the welding materials 16c and 16d between both ends in the plate width direction of the preceding plate 4 and the succeeding plate 5 (step S106). In step S106, the pressing portions 17 and 18 continue from step S105 described above, sandwich the welding material 16c between the plate width end portion 4a and the plate width end portion 5a, and the plate width end portion 4b. The welding material 16d is clamped between the plate width end portions 5b (see FIG. 6). At the same time, the electric welding part 16 heats and melts the sandwiched welding materials 16c and 16d by energization heating. That is, as shown in FIG. 6, the welding power source 16e supplies power to the vicinity of the plate width end portions 4a and 5a of the leading plate 4 and the trailing plate 5 via the electrodes P1 and P2, and the welding power source 16f Power is supplied to the vicinity of the plate width end portions 4b and 5b of the leading plate 4 and the trailing plate 5 through P3 and P4. Further, the welding power source 16g supplies power to the vicinity of the intermediate portions 4c and 5c of the leading plate 4 and the trailing plate 5 via the electrodes P5 and P6. As a result, the welding power sources 16e to 16g flow current to the leading end portions of the leading plate 4 and the trailing plate 5 through the welding materials 16c and 16d. For example, as shown in FIG. 6, the current 9a from the welding power sources 16e and 16g flows through the plate width end portion 5a of the succeeding plate 5 in a concentrated manner on the welding material 16c, and then the plate width end portion of the preceding plate 4 It flows to 4a. Thus, the current 9a flows concentratedly on the welding material 16c, so that the welding material 16c generates Joule heat, and the welding material 16c is heated and melted by Joule heat derived from the current 9a. At the same time, the current 9 b from the welding power sources 16 f and 16 g flows through the plate width end portion 5 b of the succeeding plate 5 to the welding material 16 d and then flows to the plate width end portion 4 b of the preceding plate 4. Thus, the current 9b flows concentratedly on the welding material 16d, so that the welding material 16d generates Joule heat, and the welding material 16d is heated and melted by Joule heat derived from the current 9b.

  In this step S106, the welding power sources 16f to 16g are connected to the plate width end portions 4a and 4b of the preceding plate 4 and the plate of the succeeding plate 5 together with the welding materials 16c and 16d by Joule heat derived from the currents 9a and 9b. The width end portions 5a and 5b are energized and heated. That is, the plate width end portion 4a of the preceding plate 4 and the plate width end portion 5a of the succeeding plate 5 are heated to a temperature sufficient for heating and bonding between the steel plates by Joule heat derived from the current 9a, for example, the preceding plate 4 and the following plate. Heated to a temperature above the solidus of the plate 5. Similarly, the plate width end portion 4b of the preceding plate 4 and the plate width end portion 5b of the succeeding plate 5 are heated to a temperature sufficient for heating and joining the steel plates by Joule heat derived from the current 9b. In addition, the energization heating of this step S106 is the 2nd step heat processing with respect to the leading edge part of the preceding board 4 and the succeeding board 5 of heat joining object.

  Subsequently, the metal plate joining apparatus 10 presses and joins the tail end portion of the preceding plate 4 and the tip end portion of the succeeding plate 5 while continuing to heat and melt the welding materials 16c and 16d in step S106 described above. (Step S107). In step S107, the pressing parts 17 and 18 continue to press the leading ends of the preceding material 4 and the succeeding material 5 during the period in which the welding power sources 16f to 16g heat and melt the welding materials 16c and 16d. Further, the pressing portions 17 and 18 continue to press the leading end portions while the welding power sources 16f to 16g energize and heat the plate width end portions 4a, 4b, 5a, and 5b of the preceding plate 4 and the succeeding plate 5. To do. Due to the pressing action during both periods, the molten welding material 16c spreads over the entire region between the plate width end portions 4a, 5a of the preceding plate 4 and the succeeding plate 5, and the plate width end portions 4a, 5a The oxides present on the opposite end surfaces of the leading plate 4 and the trailing plate 5 are washed out of the joint surface between the leading end portions. Similarly, the welded material 16d in a molten state flows and spreads over the entire region between the plate width end portions 4b and 5b of the preceding plate 4 and the succeeding plate 5, and the opposite end surfaces of the plate width end portions 4b and 5b are opposed to each other. The oxide present in the substrate is washed out of the joint surface between the leading ends of the leading plate 4 and the trailing plate 5.

  Moreover, the press parts 17 and 18 join this leading edge part over the whole board width by continuing pressing the leading edge parts of the preceding board 4 and the succeeding board 5 during both the above-mentioned periods. . That is, as shown in FIG. 7, the pressing portions 17, 18 are connected to the plate width end portion 4 a of the preceding plate 4 via the welding material 16 c by pressing between the leading end portions of the leading plate 4 and the trailing plate 5. While joining the board width end part 5a of the succeeding board 5, the board width end part 4b of the preceding board 4 and the board width end part 5b of the succeeding board 5 are joined via the welding material 16d. Following this, the pressing portions 17 and 18 are intermediate portions 4c and 5c that are already heated to an appropriate temperature by the induction heating in step S102 described above, among the leading ends of the leading plate 4 and the trailing plate 5. Press. The intermediate portions 4c and 5c can come into contact with each other after the above-described welding materials 16c and 16d are melted and deformed. The pressing parts 17 and 18 join such intermediate parts 4c and 5c by pressing. As a result, as shown in FIG. 7, the metal plate joining apparatus 10 heat-joins the leading end portions of the leading plate 4 and the trailing plate 5 well over the entire region in the plate width direction.

  Thereafter, the metal plate joining apparatus 10 completes the heat joining between the leading ends of the preceding plate 4 and the succeeding plate 5. Specifically, the control unit 19 stops pressing the leading end portions of the preceding plate 4 and the succeeding plate 5 at the timing when a predetermined time has elapsed from the pressing in step S107, and the leading plate 4 and the rear plate The pressing portions 17 and 18 are controlled so as to release the clamp of the row plate 5. Further, the control unit 19 turns on the welding power sources 16e to 16g so as to stop the power supply to the leading end portions of the leading plate 4 and the trailing plate 5 at a timing when a predetermined time has elapsed from the start of the energization heating in Step S106. Control. Note that, as described above, the preceding plate 4 and the succeeding plate 5 in which the heating and joining of the leading end portions are completed are transported to the finish rolling section 2 side along the transport path 3 shown in FIG.

  Such a metal plate joining apparatus 10 performs each processing step of steps S101-S107 mentioned above with respect to the some steel plate conveyed sequentially along the conveyance path | route 3 (refer FIG. 1). Thereby, the metal plate joining apparatus 10 heat-joins each opposing edge part of these some steel plates reliably over the whole board width. As a result, the metal plate joining apparatus 10 obtains a series of steel plates obtained by integrating the plurality of steel plates into a strip shape.

  Here, in steps S101 to S107 described above, an alloy containing a predetermined amount or more of an easily oxidizable alloy element such as Si, Mn, Cr, Ti, or Al as the preceding plate 4 and the succeeding plate 5 to be heat-bonded. When steel is used, a low alloy steel material that is the same alloy element as the alloy elements contained in the leading plate 4 and the trailing plate 5 and does not contain anything other than carbon may be used as the welding materials 16c and 16d. For example, when alloy steel containing 0.2 [mass%] or more and 3.5 [mass%] or less of Si is used as the leading plate 4 and the trailing plate 5, Si is used as the welding materials 16c and 16d. What is necessary is just to use low alloy steel, such as the low carbon steel which does not contain.

  As described above, in Embodiment 1 of the present invention, the tail end portion of the preceding plate and the tip portion of the succeeding plate that are opposed to each other in a state of being separated from each other are induction-heated, and the tail end portion after this induction heating is performed. Both plate width ends of the preceding plate through the welding material between the respective plate width ends from a plurality of electrodes while sandwiching the welding material between each of the plate width ends of the two plates A current is passed through both ends of the succeeding plate to heat and melt each of the clamped welding materials, and in parallel, the leading ends of the preceding and succeeding plates are pressed together. ing.

  For this reason, the first stage heat treatment for the leading and trailing edges of the preceding and succeeding plates, that is, induction heating of the leading and trailing edges, the opposing portion of the leading and trailing edges excluding the plate width edge (FIG. 7). The intermediate portions 4c, 5c) shown in the above can be heated to a temperature exceeding the solidus of the preceding and succeeding plates. In addition, it is possible to flow the current concentrated on the welding material sandwiched between the plate width end portions of the leading end after this induction heating, and by the synergistic action of the welding pressure and melting of this welding material, The welding material can be poured into the entire region between the plate width end portions of the leading end portion, and the oxide present on the opposing end surfaces of the plate width end portions can be flowed out of the joining surface between the leading end portions. it can. Furthermore, after the melt deformation of the welding material between the respective plate width end portions, the intermediate portions of the leading end portions that have already been heated by the heat treatment in the first stage can be pressed and joined. As a result, the front and rear ends can be joined over the entire region in the plate width direction, and the plasticity such as ductility of the welding material intervening at the joining interface between the plate width ends can be improved. Bonding strength can be improved. Furthermore, it is possible to stop the progress of cracks that originated from an oxide (for example, an oxide containing an easily oxidizable alloy element) at the joint interface between the leading and trailing ends by the plasticity of the welding material. From the above, it is possible to reliably heat-join the leading and trailing ends of a plurality of steel plates across their entire width without being affected by oxides containing easily oxidizable alloy elements. Even in the case of heat bonding between alloy steels containing elements, it is possible to suppress the breakage of the bonded portion between the tail ends.

  By using the metal plate joining apparatus and the metal plate joining method according to the first embodiment of the present invention, the tip of a plurality of steel plates to be conveyed regardless of whether or not the steel plate contains an easily oxidizable alloy element. The tail ends can be heat-bonded in sequence over the entire plate width. As a result, the plurality of steel plates can be efficiently processed into a series of continuous steel plates, and sufficient bonding strength between the steel plates in the series of steel plates can be secured to prevent breakage of the series of steel plates. . Such a series of steel plates is useful, for example, for endless rolling in which a plurality of steel plates are continuously finish-rolled without interruption.

  Further, in Embodiment 1 of the present invention, the shape and dimensions of the welding material are set so that the contact area between the opposing end surface of the leading end portion of the leading plate and the trailing plate and the welding material is as small as possible. Yes. For this reason, when a welding material is pinched between each plate width end part of a preceding board and a succeeding board, the surface pressure from the welding material applied to the opposing end surface between each plate width end part can be strengthened. . Thereby, the oxide on the opposing end surface between each plate | board width edge part can be easily broken by a welding material. As a result, with the flow of the welding material in the molten and pinched state, the oxide can be more easily flowed out of the joint surface between the respective plate width ends, so that the joint strength between the leading ends can be improved, Both effects of suppressing the progress of fracture at the joint portion can be promoted.

  In particular, when an alloy steel containing Si of 0.2 [mass%] or more and 3.5 [mass%] or less is used as a leading plate and a trailing plate, each width end of the leading plate and the trailing plate A low alloy steel such as low carbon steel is used as a welding material sandwiched between the parts. Thereby, together with the flow of the welded material in the molten / clamping state, the Si oxide can be easily flowed out of the joint surface between the plate width ends. As a result, it is possible to reliably heat-join the leading and trailing ends of a plurality of steel plates across the entire width without affecting the Si oxide, and the leading and trailing ends starting from the Si oxide. It is possible to reliably stop the progress of breakage between the joint portions.

  Next, Example 1 of the present invention will be described. In Example 1, alloy steel containing an easily oxidizable alloy element (C, Si, Mn) was used as the leading plate 4 and the trailing plate 5 (see FIGS. 1, 3 and the like) to be heat-bonded. . On the other hand, as the welding materials 16c and 16d, low carbon steel having a carbon content of 0.01 [% C] in the steel was used. Moreover, the dimension of the cross section of the welding materials 16c and 16d was 5 [mm] × 15 [mm]. Under such conditions, the leading plate 4 and the succeeding plate 5 are sequentially conveyed along the conveying path 3 of the hot rolling line shown in FIG. The processing steps of steps S101 to S107 shown in FIG.

  Specifically, the above-described slab of alloy steel was roughly rolled by the rough rolling section 1 after heat treatment by a heating furnace (not shown). Thus, the leading plate 4 and the trailing plate 5 having a plate thickness of 40 [mm], a plate width of 1800 [mm], a length of 100 [m], and a temperature of 1060 [° C.] are obtained. It was. Next, the leading end portions of the leading plate 4 and the trailing plate 5 are cut by the cutting portion 11, and the opposing end surfaces of the leading end portions are formed into smooth shapes that can be engaged with each other (see step S101). .

  Next, by the action of the induction heating unit 12 and the pressing units 17 and 18, the tail end portion of the preceding plate 4 and the tip end portion of the succeeding plate 5 are induction heated in a state of being separated from each other (see step S102). As a result, the intermediate portion 4c sandwiched between the two plate width end portions 4a, 4b of the leading end portion of the preceding plate 4, and the both plate width end portions 5a, 5b of the tail end portion of the trailing plate 5. The intermediate portion 5c sandwiched between the layers was in a state of 1440 to 1490 [° C.] (temperature exceeding the solidus of the alloy steel). At this time, the temperatures of the plate width end portions 4a and 4b of the preceding plate 4 and the plate width end portions 5a and 5b of the succeeding plate 5 are caused by the characteristics of the energization paths of the eddy currents 8a and 8b shown in FIG. It was below the solidus line of this alloy steel. For example, among the plate width end portions 4a and 4b of the preceding plate 4, the temperature of the portion from the corner portion to the distance of 100 [mm] remains at 1400 [° C.] or less. The same applies to the plate width end portions 5a and 5b of the succeeding plate 5.

  Subsequently, the welding materials 16c and 16d having the above-described conditions were fed between the plate width end portions 4a and 4b of the preceding plate 4 after induction heating and the plate width end portions 5a and 5b of the succeeding plate 5, respectively. (See step S104). Next, the welding material 16c is sandwiched between the plate width end portions 4a and 5a by pressing the leading end portions of the leading plate 4 and the trailing plate 5 by the pressing portions 17 and 18, and the plate width end portions 4b and 5b. The welding material 16d was sandwiched between them (see step S105). Immediately thereafter, the plurality of electrodes P1 to P6 are pressed against the predetermined positions of the leading end portions of the leading plate 4 and the trailing plate 5, and currents from the plurality of electrodes P1 to P6 are passed through the welding materials 16c and 16d. It flowed to the tail end (see FIG. 6). In this case, the current from the electrodes P1 to P6 flows concentratedly in the welding material 16c between the plate width end portions 4a and 5a and the welding material 16d between the plate width end portions 4b and 5b, and Joule heat derived from this current. Thus, the welding materials 16c and 16d were heated and melted. Furthermore, a current flows to both plate width end portions 4a, 4b, 5a, and 5b through the welded materials 16c and 16d in a sandwiched and molten state, and the plate width end portions 4a and 4b are caused by Joule heat derived from this current. , 5a, 5b were heated by energization. As a result, the plate width end portions 4a, 4b, 5a, 5b were in a high temperature state of 1500 [° C.] or higher (see step S106). While continuing these operations, the leading end portions of the leading plate 4 and the trailing plate 5 were pressed and joined by the pressing portions 17 and 18 (see step S107).

  As described above, the leading end portions of the leading plate 4 and the trailing plate 5 are joined to each other over the entire plate width, and as a result, the leading plate 4 and the trailing plate 5 are connected in the conveying direction. A series of steel plates was obtained. In Example 1, a plurality of such a series of steel plates was manufactured and classified into four samples # 1 to # 4 according to the composition of the alloy elements contained. Moreover, as a comparative example of samples # 1 to # 4, a series of steel plate samples # 5 to # 8 were manufactured. In addition, in the heat joining method of samples # 5 to # 8, the leading end portions of the leading plate 4 and the trailing plate 5 are heated and press-bonded only by induction heating in step S102 without using the welding materials 16c and 16d. . Other methods were the same as those of samples # 1 to # 4.

  In Example 1, each of the samples # 1 to # 8 after heat bonding was finish-rolled by the finish rolling unit 2 (see FIG. 1), and the fracture occurrence rate during the finish rolling was evaluated. Table 1 shows the evaluation results of the fracture occurrence rate of samples # 1 to # 8. In addition, this fracture occurrence rate was calculated by dividing the number of fractures that occurred by the total number of finish rollings (total number of rollings). In Table 1, “use of low carbon welding material” means that the heating method is based on the metal plate joining method according to the first embodiment described above. That is, the sample corresponding to the description of “use of low carbon welding material” is heat-bonded according to the metal plate bonding method according to the first embodiment. On the other hand, the description of “only heating in the first stage” means that the process of heating the leading end portions of the leading plate 4 and the trailing plate 5 is the heating method using only induction heating in step S102. In addition, “component” in Table 1 indicates the content of alloy elements (C, Si, Mn) in the steel sheet.

  As shown in Table 1, the Si content of Samples # 1 and # 5 is 0.1 [% Si], the Si content of Samples # 2 and # 6 is 0.2 [% Si], and Sample # 3 , # 7 had a Si content of 0.5 [% Si], and Samples # 4 and # 8 had a Si content of 1.2 [% Si]. Moreover, C content and Mn content were made common to all the samples # 1 to # 8, and were set to 0.12 [% C] and 0.8 [% Mn], respectively.

  As a result of comparing the samples # 1 to # 4 among the samples # 1 to # 8 as described above, when the steel plates are heated and joined by the metal plate joining apparatus 10 and the metal plate joining method according to the first embodiment, It has been found that even when the Si content is increased from 0.1 [% Si] to 1.2 [% Si], the fracture occurrence rate during finish rolling can be suppressed to a practical level. In particular, as can be seen from the results of samples # 3 and # 4, the metal plate according to the first embodiment even when the Si content is large (0.5 [% Si], 1.2 [% Si]). According to the joining apparatus 10 and the metal plate joining method, the fracture occurrence rate during finish rolling could be suppressed to 3%.

  On the other hand, when samples # 5 to # 8 were compared, in the heat joining of steel plates by induction heating alone, the fracture occurrence rate during finish rolling increased with an increase in Si content. In particular, when the Si content was 0.2 [% Si] or more, the fracture occurrence rate was as high as 20 [%] or more. When this Si content is 0.2 [% Si] or more (samples # 6 to # 8), the fracture occurrence rate is extremely high as can be seen from the above-described samples # 1 to # 4. It was.

  From the above, in Example 1, by using the metal plate joining apparatus 10 according to the first embodiment and heating and joining the steel plates according to the metal plate joining method according to the first embodiment, the Si content in the steel plate Even in a large amount (strongly 1.0 [% Si]), it was found that the fracture of the joint portion between the steel plates during finish rolling can be suppressed. The Si content in the steel sheet is preferably 3.5 [% Si] or less from the viewpoint of ease of finish rolling of a series of steel sheets. This is because when the Si content in the steel sheet exceeds 3.5 [% Si], the ductility of the steel sheet itself is significantly reduced, and as a result, it becomes difficult to roll the steel sheet.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. In the first embodiment described above, the welding material between the leading and trailing end portions of the preceding plate and the succeeding plate is heated and melted by energization heating using a plurality of electrodes. However, in the second embodiment, the alternating magnetic field The welding material between the leading end portions of the preceding plate and the succeeding plate is heated and melted by induction heating by application.

  FIG. 8 is a block diagram illustrating a configuration example of the metal plate joining apparatus according to the second embodiment of the present invention. As shown in FIG. 8, the metal plate joining apparatus 20 according to the second embodiment includes a welding material feeding unit 26 instead of the electric welding part 16 of the metal plate joining apparatus 10 according to the first embodiment described above. A control unit 29 is provided instead of the control unit 19. Other configurations are the same as those of the first embodiment, and the same reference numerals are given to the same components.

  The welding material feeding section 26 has a welding material between each of the plate width direction both ends at the tail end portion of the preceding plate 4 after induction heating and between the plate width direction both ends at the tip portion of the succeeding plate 5 after induction heating. To send. FIG. 9 is a schematic diagram illustrating a configuration example of a welding material feeding unit of the metal plate joining apparatus according to the second embodiment. The welding material feeding unit 26 has the same feeding function of the welding materials 16c and 16d as the electric welding unit 16 in the first embodiment. That is, as shown in FIG. 9, the welding material feeding unit 26 includes welding material feeding rollers 16a and 16b similar to those in the first embodiment. As shown in FIG. 9, the welding material feeding section 26 has a welding material 16 c between the plate width end portions 4 a and 5 a of the preceding plate 4 and the following plate 5 by the rotation of the welding material feeding roller 16 a. The welding material 16d is fed between the plate width end portions 4b and 5b of the preceding plate 4 and the following plate 5 by the rotation of the welding material feeding roller 16b.

  The control unit 29 controls the cutting unit 11, the induction heating unit 12, the welding material feeding unit 26, and the pressing units 17 and 18. In this case, the control unit 29 is partially different from the control unit 19 in the first embodiment only in the control function for the induction heating unit 12. That is, the control unit 29 induction-heats the tail end portion of the preceding plate 4 and the tip end portion of the succeeding plate 5 that are opposed to each other inside the coil pair 13 (see FIG. 2) of the induction heating unit 12 while being separated from each other. In this way, the induction heating unit 12 is controlled. Thereafter, the control unit 29 induces the induction heating to be stopped at a timing when the induction heating of the tail end portion of the preceding plate 4 and the tip end portion of the succeeding plate 5 which are separated from each other is performed for a predetermined time. The heating unit 12 is controlled. The control unit 29 also includes the tail end portion of the leading plate 4 and the trailing plate 5 that are connected to each other via the welding materials 16c and 16d after the welding materials 16c and 16d are pressed by the pressing portions 17 and 18. The induction heating unit 12 is controlled such that an alternating magnetic field is applied to the tip of the welding member 16c and 16d to induce induction heating. In this case, the control unit 29 controls the induction heating unit 12 so that the induction heating of the welding materials 16c and 16d is continued for a predetermined time. Further, the control unit 29 continues to press the tail end portion of the leading plate 4 and the leading end portion of the succeeding plate 5 for a time longer than the duration of the induction heating of the welding materials 16c and 16d by the dielectric heating unit 12. The pressing parts 17 and 18 are controlled.

  The control unit 29 controls the induction heating strength of the welding materials 16c and 16d by the induction heating unit 12. Specifically, the control unit 29 controls the strength of the alternating magnetic field generated by the coil pair 13 in the same manner as in the case of controlling the induction heating strength of the leading end portions of the leading plate 4 and the trailing plate 5 in the first embodiment. Thus, the intensity of the eddy currents induced at the leading ends of the leading plate 4 and the trailing plate 5 is controlled. The control unit 29 controls the induction heating strength of the welding materials 16c and 16d between the leading end portions of the leading plate 4 and the trailing plate 5 through the control of the eddy current. For example, the control unit 29 controls the induction heating unit 12 to alter the alternating power at the time of induction heating of the welding materials 16c and 16d as compared to the first stage induction heating of the leading end portion of the leading plate 4 and the trailing plate 5. The magnetic field is strengthened, thereby strengthening the induction heating on the welding materials 16c and 16d as compared with the first stage induction heating. In addition, the control part 29 controls the induction heating intensity | strength of the leading edge part of the preceding board 4 and the succeeding board 5 by the induction heating part 12 similarly to the case of Embodiment 1. FIG.

  Based on the control of the control unit 29 as described above, the induction heating unit 12 according to the second embodiment generates an alternating magnetic field penetrating the leading plate 4 and the trailing plate 5 in the thickness direction thereof. 5, a welding material 16 c sandwiched between one plate width end portion 4 a and 5 a and a welding material 16 d sandwiched between the other plate width end portions 4 b and 5 b. Induction heating.

  The control unit 29 controls the cutting unit 11 and the pressing units 17 and 18 as in the case of the control unit 19 in the first embodiment. Moreover, the control part 29 controls the welding material supply part 26 similarly to the welding material supply control with respect to the electric welding part 16 in Embodiment 1. FIG.

  Next, a metal plate joining method according to the second embodiment of the present invention will be described. FIG. 10 is a schematic diagram for explaining the heat joining between the leading end portions of the preceding and succeeding plates in the second embodiment. In the metal plate joining method according to the second embodiment, the method for heating the welding materials 16c and 16d sandwiched between the leading ends of the preceding plate 4 and the succeeding plate 5 is the metal plate according to the first embodiment. Different from the joining method. That is, in the metal plate joining method according to the second embodiment, each processing step (see FIG. 4) of steps S101 to S105 is performed as in the first embodiment. In steps S <b> 106 and S <b> 107, induction heating by the induction heating unit 12 is performed instead of energization heating by the electric welding unit 16.

  In step S106 of the second embodiment, the metal plate joining apparatus 20 includes a welding material 16c sandwiched between the plate width end portion 4a of the preceding plate 4 and the plate width end portion 5a of the succeeding plate 5; The welding material 16 d sandwiched between the plate width end portion 4 b of the plate 4 and the plate width end portion 5 b of the succeeding plate 5 is induction-heated by the induction heating unit 12.

  Specifically, as shown in FIG. 10, the pressing portions 17 and 18 continue from step S105 described above and sandwich the welding material 16c between the plate width end portion 4a and the plate width end portion 5a, In addition, the welding material 16d is sandwiched between the plate width end portion 4b and the plate width end portion 5b. At the same time, the induction heating unit 12 heats and melts the sandwiched welding materials 16c and 16d by induction heating. That is, the coil pair 13 of the induction heating unit 12 has a predetermined time after the welding material 16c between the plate width end portions 4a and 5a and the welding material 16d between the plate width end portions 4b and 5b start to be clamped together. Power is supplied from the power source 15 (see FIG. 8) at the timing. As a result, the coil pair 13 resumes application of the alternating magnetic field to the leading end portions of the preceding plate 4 and the succeeding plate 5 that have been stopped since step S103. At this time, the leading plate 4 and the trailing plate 5 connect the plate width end portions 4a and 5a to each other through the welding material 16c, and connect the plate width end portions 4b and 5b to each other through the welding material 16d. I am letting. As shown in FIG. 10, an eddy current 8 c is induced at the leading end portions of the preceding plate 4 and the trailing plate 5 in such a connected state by applying an alternating magnetic field from the coil pair 13.

  For example, as shown in FIG. 10, the eddy current 8c flows in an arc shape from the vicinity of the center of the front end portion of the trailing plate 5 toward the plate width end portion 5a, and subsequently, welding in a pinched state from the plate width end portion 5a. It flows to the plate width end portion 4a of the preceding plate 4 through the material 16c. Next, the eddy current 8c is half-circulated from one plate width end 4a to the other plate width end 4b in the tail end of the preceding plate 4, and then welded in a pinched state from the plate width end 4b. It flows to the plate width end portion 5b of the succeeding plate 5 through the material 16d, and then flows in an arc shape from the plate width end portion 5b toward the vicinity of the center of the succeeding plate 5. In this way, the eddy current 8c circulates between the leading end portions of the leading plate 4 and the trailing plate 5 via the welding materials 16c and 16d. Here, the eddy current 8c concentrates on the welding material 16c between the plate width end portions 4a and 5a when the eddy current 8c goes around between the plate width end portions 4a and 5a of the preceding plate 4 and the succeeding plate 5. Flowing. As a result, the welding material 16c generates Joule heat, and the welding material 16c is heated and melted by Joule heat derived from the eddy current 8c. Similarly, when the eddy current 8c circulates across the other plate width end portions 4b and 5b of the preceding plate 4 and the succeeding plate 5, the eddy current 8c is applied to the welding material 16d between the plate width end portions 4b and 5b. Concentrate and flow. As a result, the welding material 16d generates Joule heat, and the welding material 16d is heated and melted by Joule heat derived from the eddy current 8c.

  Moreover, in this step S106, the induction heating part 12 makes the board width end parts 4a and 4b of the preceding board 4 and the board width end of the succeeding board 5 together with the welding materials 16c and 16d by Joule heat derived from the eddy current 8c. The parts 5a and 5b are induction-heated. That is, the plate width end portion 4a of the preceding plate 4 and the plate width end portion 5a of the succeeding plate 5 are heated to a temperature sufficient for heating and joining the steel plates by the Joule heat derived from the eddy current 8c (the preceding plate 4 and the following plate). To a temperature above the solidus of the plate 5). Similarly, the plate width end portion 4b of the preceding plate 4 and the plate width end portion 5b of the succeeding plate 5 are heated to a temperature sufficient for heating and joining the steel plates by Joule heat derived from the eddy current 8c. In addition, the induction heating of step S106 in this Embodiment 2 is a 2nd step heat processing with respect to the leading edge part of the preceding board 4 and the succeeding board 5 of heat joining object.

  On the other hand, in step S107 of the second embodiment, the metal plate joining apparatus 20 continues the heating and melting of the welding materials 16c and 16d in step S106 described above, while the tail end portion of the leading plate 4 and the trailing plate 5 The tip part is pressed and joined. Specifically, as illustrated in FIG. 10, the pressing portions 17 and 18 are configured so that the leading end portions of the leading material 4 and the trailing material 5 are connected to each other during the period in which the induction heating unit 12 heats and melts the welding materials 16 c and 16 d. Keep pressing. Further, the pressing portions 17 and 18 continue to press the leading end portions during the period in which the induction heating portion 12 induction-heats the plate width end portions 4a, 4b, 5a, and 5b of the leading plate 4 and the trailing plate 5. . Due to the pressing action during both periods, the molten welding material 16c spreads over the entire region between the plate width end portions 4a, 5a of the preceding plate 4 and the succeeding plate 5, and the plate width end portions 4a, 5a The oxides present on the opposite end surfaces of the leading plate 4 and the trailing plate 5 are washed out of the joint surface between the leading end portions. Similarly, the welded material 16d in a molten state flows and spreads over the entire region between the plate width end portions 4b and 5b of the preceding plate 4 and the succeeding plate 5, and the opposite end surfaces of the plate width end portions 4b and 5b are opposed to each other. The oxide present in the substrate is washed out of the joint surface between the leading ends of the leading plate 4 and the trailing plate 5. Further, the pressing portions 17 and 18 continue to press the leading end portions of the leading plate 4 and the trailing plate 5 during the above-described period, so that the leading end portions are connected to each other as in the first embodiment. Are joined over the entire plate width (see FIG. 10).

  Thereafter, the metal plate joining apparatus 20 completes the heat joining between the leading ends of the preceding plate 4 and the succeeding plate 5. Specifically, the control unit 29 stops the pressing of the leading end portions of the preceding plate 4 and the succeeding plate 5 at a timing when a predetermined time has elapsed since the pressing in step S107, and the leading plate 4 and the rear plate The pressing portions 17 and 18 are controlled so as to release the clamp of the row plate 5. Moreover, the control part 29 is an induction heating part so that the application of the alternating magnetic field with respect to the leading edge part of the preceding board 4 and the succeeding board 5 may be stopped at the timing which predetermined time passed from the start of the induction heating of step S106. 12 is controlled. Note that, as described above, the preceding plate 4 and the succeeding plate 5 in which the heating and joining of the leading end portions are completed are conveyed to the finish rolling unit 2 side along the conveying path 3 shown in FIG. Such a metal plate joining apparatus 20 performs each processing step of steps S101-S107 mentioned above with respect to the some steel plate conveyed sequentially along the conveyance path | route 3 (refer FIG. 8). Thereby, the metal plate joining apparatus 20 reliably heat-joins the opposing end portions of the plurality of steel plates over the entire plate width. As a result, the metal plate joining apparatus 20 obtains a series of steel plates as in the case of the first embodiment.

  In the metal plate joining method according to the second embodiment, as in the case of the first embodiment described above, the leading plate 4 and the trailing plate 5 to be heat-bonded are Si, Mn, Cr, Ti, Al. In the case of an alloy steel containing a predetermined amount or more of an easily oxidizable alloy element, the welding materials 16c and 16d are the same alloy elements as the alloy elements contained in the leading plate 4 and the trailing plate 5 and other than carbon. What is necessary is just to use the low alloy steel material which does not contain a thing. For example, when alloy steel containing 0.2 [mass%] or more and 3.5 [mass%] or less of Si is used as the leading plate 4 and the trailing plate 5, Si is used as the welding materials 16c and 16d. What is necessary is just to use low alloy steel, such as the low carbon steel which does not contain.

  As described above, in the second embodiment of the present invention, the leading edge of the leading plate and the trailing plate of the succeeding plate after induction heating are clamped with a welding material between the leading edge portions of the leading plate and the trailing plate. An alternating magnetic field is applied to the ends to induce eddy currents, and eddy currents are passed to the leading end through the welding material between the plate width ends so that each of the sandwiched welding materials is heated and melted. The other configuration is the same as that of the first embodiment.

  For this reason, while exhibiting the same effect as the case of Embodiment 1 mentioned above, the 1st step heat processing with respect to the leading edge part of a preceding board and a succeeding board, and the preceding board and succeeding board after induction heating The same induction heating part can be shared with induction heating (second stage heat treatment) of the welding material in a state of being sandwiched between the front and rear end parts. As a result, the same operational effects as those of the first embodiment described above can be enjoyed, and the downsizing of the device scale and the simplification of the device configuration can be promoted.

  On the other hand, when the leading end of the preceding plate and the trailing plate in a state of being separated from each other are pressed while being dielectrically heated, the eddy current on the leading plate side and the eddy current on the trailing plate side are instantaneously combined, As a result, the energization path of the eddy current at the leading end changes instantaneously. As a result, since the power supply voltage of the induction heating unit changes abruptly, an excessive alternating current flows through each coil and an excessive load fluctuation occurs in the power supply. As a result, the power supply of the induction heating unit may be unintentionally interrupted, which may hinder the induction heating of the leading end. In addition, each coil or power supply may be damaged due to an excessive load as described above.

  On the other hand, in Embodiment 2 of the present invention, the tail end of the preceding plate and the tip of the succeeding plate are separated from each other and induction heated, and then the leading and trailing plates of the separated plate are separated from each other. Before pressing the ends, induction heating to the leading end is stopped, and during the induction heating stop period, the tail end of the separated preceding plate and the leading end of the trailing plate are pressed against each other. The leading end and the trailing end of the succeeding plate after the first stage induction heating are connected to each other with the welding material interposed therebetween. For this reason, the leading end portions of the preceding plate and the succeeding plate after the first stage induction heating can be electrically connected by pressing without causing the instantaneous change in the energization path of the eddy current described above. As a result, unintended power interruption of the induction heating unit can be prevented, and damage to each coil and power source due to excessive load fluctuation can be prevented. As a result, the leading and trailing edges of the preceding and succeeding plates can be joined safely and efficiently without unintentionally interrupting induction heating due to power interruption or equipment damage.

  Next, a second embodiment of the present invention will be described. In Example 2, using the metal plate joining apparatus 20 according to the second embodiment, the leading end portions of the leading plate 4 and the trailing plate 5 were heated and joined according to the metal plate joining method according to the second embodiment. That is, the welding materials 16c and 16d sandwiched between the leading and trailing ends of the leading plate 4 and the trailing plate 5 are heated and melted by Joule heat derived from the eddy current 8c (see FIG. 10), and the sandwiched and melted state Both plate width end portions 4a, 4b, 5a and 5b were induction-heated by Joule heat derived from the eddy current 8c through the welding materials 16c and 16d. In the second embodiment, other conditions are substantially the same as those in the first embodiment. Also in the second embodiment, as in the first embodiment, the plate width end portions 4a, 4b, 5a, 5b are set to 1505 [° C.] (temperature exceeding the solidus of the leading plate 4 and the trailing plate 5). The temperature could be increased, and the leading ends of the leading plate 4 and the trailing plate 5 could be pressed and joined together.

  In this way, the leading end portions of the leading plate 4 and the trailing plate 5 are joined over the entire plate width, and as a result, the leading plate 4 and the trailing plate 5 are connected in the conveying direction. Steel plate was obtained. In this Example 2, a plurality of such a series of steel plates were manufactured and classified into five samples # 11 to # 15 according to the composition of the alloy elements contained. Further, as a comparative example of samples # 11 to # 15, a series of steel plate samples # 16 were manufactured. In the heat joining method of sample # 16, alloy steel containing 0.8 [% Si] Si was used as the welding materials 16c and 16d. Other methods were the same as those of samples # 11 to # 15. In addition, when the steel content whose Si content is more than a predetermined value (for example, 0.2 [% Si] or more) is heat-joined only by the first stage induction heating, the evaluation result of the above-described Example 1 (see Table 1). ), The rate of occurrence of breakage during finish rolling is extremely high. Since this is apparently the same in the second embodiment, in the second embodiment, the sample of only the first stage induction heating is excluded from the evaluation target.

  In Example 2, each of the samples # 11 to # 16 after heat bonding was finish-rolled by the finish rolling section 2 (see FIG. 8), and the fracture occurrence rate at the finish rolling was evaluated. Table 2 shows the evaluation results of the fracture occurrence rate of samples # 11 to # 16. Note that the fracture occurrence rate in Example 2 was calculated by the same method as in Example 1 described above. In Table 2, “0.8% Si welding material used” is described as “welding material 16c, 16d” using alloy steel containing 0.8 [% Si] Si, and other than this. It means that the heating method conforms to the metal plate joining method according to Form 2. In Table 2, “use of low carbon welding material” and “component” have the same meaning as in Table 1 in Example 1.

  As shown in Table 2, the C content of samples # 11, # 12, and # 16 was 0.12 [% C], and the C content of samples # 13 to # 15 was 0.13 [% Si]. . The Si content of sample # 11 is 0.8 [% Si], the Si content of samples # 12 and # 16 is 1.5 [% Si], and the Si content of sample # 13 is 2.1. [% Si], the Si content of Sample # 14 was 3.4 [% Si], and the Si content of Sample # 15 was 3.6 [% Si]. In addition, Mn content was made common about all the samples # 11- # 16, and was set to 0.8 [% Mn].

  As a result of comparing the samples # 11 to # 15 among the samples # 11 to # 16 as described above, the following was found. That is, when the steel plates are heated and joined by the metal plate joining apparatus 20 and the metal plate joining method according to the second embodiment, the Si content increases from 0.8 [% Si] to 3.4 [% Si]. However, the fracture occurrence rate during finish rolling could be suppressed to a practical level. However, as can be seen from the result of sample # 15, when the Si content increases to 3.6 [% Si], the steel plates are heated by the metal plate joining apparatus 20 and the metal plate joining method according to the second embodiment. Even in the case of joining, the fracture occurrence rate during finish rolling was as high as 25 [%].

  On the other hand, when samples # 11 to # 14 and sample # 16 are compared, in the heat joining between steel plates using alloy steels having an Si content of 0.8 [% Si] as welding materials 16c and 16d, welding is performed. It has been found that the fracture occurrence rate during finish rolling is extremely higher than when the materials 16c and 16d are low carbon steel. This increase in the fracture occurrence rate is due to the fact that the same alloy element Si as the easily oxidizable alloy element contained in the steel sheet to be heat-bonded is contained in the welding materials 16c and 16d. This is probably because the Si oxide could not be completely removed from the interface, and the progress of fracture at the end of the plate width could not be suppressed due to the Si oxide remaining at the bonding interface.

  From the above, in Example 2, by using the metal plate joining apparatus 20 according to the second embodiment, by heating and joining the steel plates according to the metal plate joining method according to the second embodiment, the Si content in the steel plate Even in a large amount (for example, 3.4 [% Si]), it was found that the fracture of the joint portion between the steel plates during finish rolling can be suppressed. Further, from the viewpoint of ease of finish rolling of a series of steel sheets and the viewpoint of ease of breakage during finish rolling, it is desirable that the Si content in the steel sheet is 3.5 [% Si] or less. I was able to confirm that.

  In the first embodiment described above, the plurality of electrodes used for energization heating of the welding material are arranged in contact with the tail end portion of the preceding plate and the tip end side of the succeeding plate, but the present invention is based on this. It is not limited. That is, out of a pair of electrodes connected to a welding power source for energizing and heating the welding material, if one electrode is placed in contact with the tail end of the preceding plate or the tip of the succeeding plate, the other electrode is welded. The material may be placed in contact with the material. For example, as shown in FIG. 11, when one electrode P1 is disposed in contact with the tip of the trailing plate 5 among the pair of electrodes P1 and P2 connected to the welding electrode 16e, the other electrode P2 is welded. What is necessary is just to arrange in contact with the material 16c. Similarly, when one electrode P3 of the pair of electrodes P3 and P4 connected to the welding electrode 16f is disposed in contact with the distal end portion of the trailing plate 5, the other electrode P4 is disposed in contact with the welding material 16d. do it.

  Moreover, in Embodiment 1 mentioned above, the three welding power supplies 16e-16g and the six electrodes P1-P6 which make a pair with respect to each were used for the energization heating of the welding materials 16c and 16d. However, the present invention is not limited to this. That is, the number of welding power sources used for energization heating of the welding materials 16c and 16d is not particularly limited to three, and may be one or may be two or more. Further, the number of electrodes arranged is not particularly limited to six as long as a pair is formed for each welding power source, and may be two or may be four or more even numbers.

  Furthermore, in Embodiment 1 and 2 mentioned above, the welding material 16c is supplied to the whole area | region between one board width | variety edge part 4a, 5a among the leading edge parts of the preceding board 4 and the succeeding board 5, Although the welding material 16d is fed to the entire region between the other plate width end portions 4b and 5b, the present invention is not limited to this. That is, the welding material 16c may be fed to a partial region between the one plate width end portions 4a and 5a, or the welding material 16d is fed to a partial region between the other plate width end portions 4b and 5b. It may be a combination thereof. For example, as shown in FIG. 12, the welding material 16c is applied to a partial region between the plate width end portions 4a and 5a from the diagonally upper side of the leading plate 4 and the trailing plate 5 by the rotating action of the welding material feeding roller 16a. May be sent. Further, the welding material 16d may be fed to a partial region between the plate width end portions 4b and 5b by the rotating action of the welding material feeding roller 16b from obliquely above the leading plate 4 and the trailing plate 5. . In this case, the necessary number of welding material feeding rollers 16a and 16b may be arranged at appropriate positions corresponding to the feeding paths of the welding materials 16c and 16d.

  In the first and second embodiments described above, the molten welding material 16 c is poured and spread between the plate width end portion 4 a of the preceding plate 4 and the plate width end portion 5 a of the succeeding plate 5. Although the welded material 16d in a molten state is poured and spread between the plate width end portion 4b and the plate width end portion 5b of the succeeding plate 5, the present invention is not limited to this, and the leading end of the preceding plate 4 and the following plate 5 The molten welding materials 16c and 16d may be spread and spread over the entire region between the parts. That is, among the leading ends of the leading plate 4 and the trailing plate 5, not only between the plate width end portions 4a and 5a and between the plate width end portions 4b and 5b but also between the intermediate portions 4c and 5c, the welding material 16c. 16d may be melted and spread. With such welding materials 16c and 16d that spread over the entire region, the oxide of the alloy element may flow out of the joint surface from the entire region of the leading end.

  Furthermore, although Embodiment 1 and 2 mentioned above illustrated the combination of the steel plate and welding material which use the welding material which consists of low carbon steel for the heat joining of Si containing steel plates, this invention is limited to this. It is not something. That is, for a steel plate to be heat-bonded, which is an alloy steel containing an easily oxidizable alloy element such as Si, Mn, Cr, Ti, Al, etc., it is the same alloy element as this contained alloy element and other than carbon (C) What is necessary is just to use the steel material of the low alloy which does not contain the thing as a welding material. For example, a low alloy steel material that does not contain Si and contains C may be used as a welding material for heat-bonding between Si-containing steel plates, or a low alloy steel material that does not contain Si and C as a welding material. It may be used.

  In the first and second embodiments described above, the induction heating unit 12 including the pair of coils 13a and 13b and the single core 14 is illustrated. However, the induction heating unit 12 is not limited to this, and the induction heating unit 12 includes a steel plate. Any number of coils and cores may be used as long as the steel plate is induction-heated using an alternating magnetic field penetrating in the plate thickness direction. For example, the induction heating unit 12 may include a plurality of pairs of coils facing each other in the plate thickness direction of the steel sheet with the conveyance path 3 interposed therebetween, or may include a plurality of cores corresponding to the plurality of pairs of coils. Good.

  Furthermore, in Embodiment 1 and 2 mentioned above, although the case where the metal plate joining apparatus concerning this invention was applied to the hot rolling line was illustrated, not only this but the metal plate joining apparatus concerning this invention is a heat | fever. The present invention may be applied to a steel material processing line or a steel material processing line other than the hot rolling line.

  Further, the present invention is not limited by the above-described embodiment, and the present invention includes a configuration in which the above-described constituent elements are appropriately combined. For example, the metal plate to be heat-bonded may be a steel plate as described above, or a metal plate other than a steel plate, such as a copper plate or an iron plate, as long as it is a metal plate that can induce eddy currents by an alternating magnetic field. Also good. In addition, all other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the above-described embodiments are included in the present invention.

DESCRIPTION OF SYMBOLS 1 Rough rolling part 2 Finish rolling part 3 Conveyance path 4 Leading plate 4a, 4b, 5a, 5b Plate width edge part 4c, 5c Intermediate part 5 Subsequent plate 8a, 8b, 8c Eddy current 9a, 9b Current 10, 20 Metal plate Joining device 11 Cutting unit 11a, 11b Cutting roller 11c Blade 12 Induction heating unit 13 Coil pair 13a, 13b Coil 14 Core 15 Power source 16 Electric welding unit 16a, 16b Welding material supply roller 16c, 16d Welding material 16e-16g Welding power source 17, 18 Pressing part 19, 29 Control part 26 Welding material supply part P1-P6 Electrode

Claims (12)

Inductively heating the tail end portion of the preceding preceding metal plate of the plurality of metal plates conveyed along the conveying path and the leading end portion of the succeeding metal plate following the preceding metal plate, and after induction heating In the metal plate joining apparatus for heating and joining the tail end and the tip,
A welding material feeding unit that feeds a welding material between each of both ends of the tail end in the plate width direction after induction heating and both ends in the plate width direction of the tip after induction heating;
A pressing portion that presses the tail end portion after induction heating and the tip end portion after induction heating and sandwiches the welding material between both ends in the plate width direction; and
A heating section that heats and melts the welding material by passing an electric current through the welding material sandwiched between both ends of the both plate width directions;
At least during the period when the heating unit heats and melts the welding material, the tail end portion after induction heating and the tip end portion after induction heating while sandwiching the welding material between both ends in the plate width direction A control unit that controls the pressing unit so as to press and
A metal plate joining apparatus comprising:   The heating unit applies an alternating magnetic field penetrating the metal plate in the plate thickness direction of the metal plate to the tail end portion and the tip end portion, and sandwiches between both ends in the plate width direction. The metal plate joining device according to claim 1, wherein the welding member is an induction heating unit that induction-heats the welded material.   The metal plate bonding apparatus according to claim 2, wherein the induction heating unit performs induction heating of the tail end portion and the tip end portion facing each other in a state of being separated from each other by application of the alternating magnetic field.   The control unit controls the induction heating unit to stop induction heating of the tail end part and the tip end part separated from each other, and the tail end after induction heating is stopped during the induction heating stop period. The pressing portion is controlled so as to press the welding portion and the tip end portion after induction heating so that the welding material is sandwiched between each of the both ends in the plate width direction, and connected to each other via the welding material The metal plate joining apparatus according to claim 3, wherein the induction heating unit is controlled to apply the alternating magnetic field to the tail end portion and the tip end portion in a state to inductively heat the welding material. .   The heating unit is an energization heating unit that uses a plurality of electrodes and applies an electric current to the welding material sandwiched between both ends in the plate width direction to energize and heat the welding material. The metal plate joining apparatus according to claim 1, wherein the apparatus is a metal plate joining apparatus. The metal plate is an alloy steel containing silicon of 0.2 [mass%] or more and 3.5 [mass%] or less,
The metal plate joining apparatus according to any one of claims 1 to 5, wherein the welding material is low carbon steel. Inductively heating the tail end portion of the preceding preceding metal plate of the plurality of metal plates conveyed along the conveying path and the leading end portion of the succeeding metal plate following the preceding metal plate, and after induction heating In the metal plate joining method of heating and joining the tail end and the tip end,
A welding material feeding step of feeding a welding material between each end portion in the plate width direction of the tail end portion after induction heating and both end portions in the plate width direction of the tip end portion after induction heating;
A welding material clamping step of pressing the tail end portion after induction heating and the tip end portion after induction heating to sandwich the welding material between both ends in the plate width direction;
A heating and melting step of heating and melting the welding material by passing an electric current through the welding material while sandwiching the welding material between both ends in the plate width direction;
The metal plate joining method characterized by including.   In the heating and melting step, an alternating magnetic field penetrating the metal plate in the plate thickness direction of the metal plate is applied to the tail end portion and the tip end portion and sandwiched between both ends in the plate width direction. The metal plate joining method according to claim 7, wherein the pressed welding material is induction-heated. An induction heating step of induction heating the tail end and the tip facing each other in a state of being separated from each other by application of the alternating magnetic field;
9. The metal plate joining method according to claim 7, wherein the welding material feeding step feeds the welding material between both ends of the plate width direction after the induction heating in the induction heating step. . An induction heating stop step of stopping induction heating for the tail end portion and the tip end portion in a state of being separated from each other;
In the welding material clamping step, during the induction heating stop period, the tail end portion after induction heating and the tip end portion after induction heating are pressed between each of both end portions in the plate width direction. Sandwiching the welding material,
The heating and melting step applies the alternating magnetic field to the tail end portion and the tip end portion that are connected to each other via the welding material to induction-heat the welding material. The metal plate joining method as described.   In the heating and melting step, a plurality of electrodes are used, and an electric current is passed through the welding material sandwiched between each of both end portions in the plate width direction, whereby the welding material is energized and heated. Item 8. The metal plate joining method according to Item 7. As the metal plate, alloy steel containing silicon of 0.2 [mass%] or more and 3.5 [mass%] or less,
The metal plate joining method according to any one of claims 7 to 11, wherein low carbon steel is used as the welding material.

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