JP2019168115A - Continuous heat treatment device and modifying method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently heat a steel slab and, when conducting a post-treatment such as a rolling by guiding the heated steel to a post-treatment device such as a rolling device, appropriately perform a post-treatment such as a rolling. Be able to do it. SOLUTION: In a continuous heat treatment apparatus for transporting a steel material X and heating it by a plurality of heating furnaces to treat the steel material, a first induction heating furnace 10 and a combustion type direct-fired heating furnace using a combustion burner 21 are used. 20A and the second induction heating furnace 30 in this order for heating, and the steel material heated by the second induction heating furnace is guided to the post-processing device 50 to perform processing such as rolling. [Selection diagram] Fig. 1

Description

  The present invention relates to a continuous heat treatment apparatus in which a steel material is conveyed and sequentially heated by a heating furnace and processed, and a method for modifying such a continuous heat treatment apparatus. In particular, in the above-described continuous heat treatment apparatus, when steel materials such as steel slabs and steel plates are efficiently heated, and when the heated steel materials are led to a post-treatment device for post-treatment, for example, the heated steel slab is rolled into a rolling device When the steel is introduced into the aftertreatment device and rolled, the heated steel slab can be appropriately rolled so as to be homogeneous, and the existing continuous heat treatment device is modified so that the continuous heat treatment as described above is performed. It is characterized in that the apparatus can be easily obtained.

  Conventionally, as shown in Patent Documents 1 and 2, steel slabs using steel materials are sequentially heated in a heating furnace, and thus the steel slabs are guided to a rolling device of a post-processing device by a conveying member such as a roller. The steel slab heated by this rolling apparatus is rolled.

  Here, when the steel slab heated by the heating furnace in this way is guided to a rolling device by a conveying member such as a conveying roller, and the heated steel slab is rolled by the rolling device, the heated steel slab is While being guided to the rolling device by the conveying member, the surface temperature of the heated steel slab is lowered, the temperature difference between the internal temperature and the surface temperature of the steel slab is increased, and is heated by the rolling device as described above. When rolling a steel slab, there was a problem that the uniformity of products such as a steel plate after rolling was lowered.

  In recent years, the demand for high-strength steel sheets containing high carbon components and thin and strong has increased. When producing such high-strength steel sheets by heating the steel pieces, When heating, there is a problem that the carbon component contained in the steel slab is largely removed, and therefore it is necessary to shorten the time until the steel slab is heated to a predetermined temperature.

  In addition, as a heating furnace for heating a steel piece such as a steel strip or a long strip obtained by rolling the steel piece, for example, a direct fire in which fuel is burned by a combustion burner provided on the furnace wall and the steel is heated by a flame. 2. Description of the Related Art An induction heating furnace and an induction heating furnace that heats steel by generating a heating current by electromagnetic induction using electric power are widely used.

  Here, in the case of the above-mentioned direct-fired heating furnace, the steel material can be heated to a high temperature by a combustion burner having a relatively simple structure. Mainly, the radiant heat from the flame is directly applied to the steel material and the inner surface of the furnace. By providing by heat radiation from the combustion heat energy can be directly used for heating, and there is an advantage that it is energy efficient.

  However, in the case of a direct-fired heating furnace, heating is performed from the surface side of the steel material. Therefore, in order to bring the inside of the steel material to the target heating temperature, it is necessary to raise the furnace temperature and the combustion exhaust gas above this target temperature. For this reason, the exhaust gas emission temperature due to combustion in the combustion burner increases, heat loss due to heat dissipation increases, energy efficiency deteriorates, and furnace materials and heat insulation that withstand high temperatures are required, resulting in equipment costs However, since the steel material is heated by combustion in an oxidizing atmosphere, the material of the steel material is deteriorated by oxidation.

  On the other hand, in the case of the induction heating furnace, since the fuel is not burned, the material quality of the steel material is not deteriorated by oxidation, and the amount of scale and decarburization can be reduced, so that the surface property of the steel material is improved. It can be heated to the inside of the steel material by electromagnetic induction, so the temperature difference in the thickness direction of the steel material is small, the inside of the steel material can be heated to a uniform temperature, and compared to the combustion heating method, the steel material Can be heated at a remarkably high heating rate, the quality of the steel material can be improved, the furnace structure is simple, the operation and handling are easy, and no combustion exhaust gas is generated. There is an advantage that processing problems are eliminated.

  However, in the case of the induction furnace described above, in order to heat the steel material to a high temperature, it is necessary to cool the induction heating coil through cooling water to protect the coil, and the heat dissipation associated with this cooling is required. The loss is remarkably large, and because it is heating by electric power, the energy use efficiency is low due to the energy loss in the power generation and transmission processes and the energy loss in the induction heating furnace body, and the cost required per unit amount is high. was there.

  In addition, as shown in Patent Documents 3 to 5 and the like, a continuous heat treatment apparatus that uses a combination of the direct-fired heating furnace and the induction heating furnace has also been proposed in the past. ing.

  However, even in the case where the direct heating furnace and the induction heating furnace are combined in this way, the steel material such as a steel strip or a long strip obtained by rolling the steel strip is appropriately heated and post-processed. For example, after a steel piece is heated by combining a direct-fired heating furnace and an induction heating furnace, the steel piece thus heated is heated by a guide roller etc. When rolling to the rolling device, the temperature of the surface of the steel slab and the end faces on both sides of the steel slab decreased during the guiding to the rolling device, and the steel slab heated by the rolling device could not be properly rolled and rolled. There existed a problem that the uniformity of products, such as a later steel plate, fell.

JP 2012-206154 A JP2013-87300A Japanese Patent Laid-Open No. 11-293341 Japanese Utility Model Publication No. 61-41440 Japanese Patent Laid-Open No. Sho 62-243718

  The present invention solves the above-mentioned problems in a continuous heat treatment apparatus that conveys steel materials and sequentially heats them in a heating furnace, and uses such an existing continuous heat treatment apparatus. It is an object to make it easy to obtain a processing apparatus.

  That is, in the continuous heat treatment apparatus of the present invention, steel materials such as steel slabs and steel plates are efficiently heated, and when the heated steel materials are led to a post-treatment device for post-treatment, for example, When rolling to a post-processing device consisting of a rolling device, the heated steel slab can be appropriately rolled so as to be homogeneous, and the existing continuous heat processing device is modified so that the continuous It is an object to make it easy to obtain a heat treatment apparatus.

  In the continuous heat treatment apparatus according to the present invention, in order to solve the above-described problems, in the continuous heat treatment apparatus in which the steel material is transported and heated by a plurality of heating furnaces, the steel material is subjected to the first induction heating. It is characterized by being conveyed in the order of a furnace, a combustion heating furnace using a combustion burner, and a second induction heating furnace.

  As described above, when the steel material is heated by the first induction heating furnace, the temperature reaches a predetermined temperature, generally the Curie point, as compared with the combustion heating furnace in which the fuel is burned using the combustion burner. Can heat the steel material efficiently, while suppressing the deterioration of the steel material due to oxidation when heating the steel material, reducing the generation of combustion exhaust gas and heat loss due to the fuel exhaust gas, and heating the steel material efficiently Furthermore, the amount of scale and decarburization during the production of high-strength steel sheets and the like can be reduced.

  Moreover, when the steel material heated by the 1st induction heating furnace as mentioned above is led and heated to the combustion type heating furnace using a combustion burner, the said heated steel material is made uniform to predetermined temperature faster. Can be heated.

  In addition, when the second induction heating furnace is provided downstream of the combustion heating furnace using the combustion burner in the steel conveyance direction, the steel heated in the combustion heating furnace is guided using a conveyance roller or the like. Even when the temperature of the front and back surfaces of the heated steel material and each end surface is lowered in the middle of changing the transport direction by the transport unit and guiding it to the post-processing device such as a rolling device, the second induction furnace is used. Thus, in the state which heated the surface and each end surface of steel materials in which temperature fell appropriately, it can guide to post-processing apparatuses, such as a rolling device, and can perform post-processing.

  Here, as the combustion-type heating furnace using the combustion burner, a direct-fired heating furnace or an indirect heating-type heating furnace can be used, but the heated steel material is uniformly heated to a predetermined temperature faster. Therefore, it is preferable to use a direct-fired heating furnace as the combustion heating furnace. On the other hand, if an indirect heating furnace in which fuel is burned by a combustion burner in a radiant tube provided in the furnace is used, even if the steel material is a thin steel plate, this steel plate becomes combustion exhaust gas. It becomes possible to prevent oxidation by direct contact.

  Further, in the remodeling method of the continuous heat treatment apparatus according to the present invention, in remodeling the continuous heat treatment apparatus provided with only the direct-fired heating furnace that conveys and heat-treats the steel material, In addition, a first induction heating furnace is provided at a position upstream of the steel material in the conveyance direction, and a second induction heating furnace is provided at a position downstream of the direct-fired heating furnace in the conveyance direction of the steel material. Like that.

  Further, in the remodeling method of the continuous heat treatment apparatus in the present invention, a direct-fired heating furnace that transports and heat-treats the steel material, and either the upstream side or the downstream side of the steel material transport direction from the direct-fired heating furnace. On the other hand, when remodeling a continuous heat treatment apparatus provided with an induction heating furnace, the induction type is positioned at a position upstream or downstream in the conveying direction of the steel material than a direct-fired heating furnace without an induction heating furnace. Provide a heating furnace.

  Here, as each of the induction heating furnaces, various induction heating furnaces can be selected and used according to the application for heating the steel material. For example, when heating the entire steel material, the tunnel type It is preferable to use an overall heating type induction heating furnace such as a horizontal type or a transverse type. On the other hand, when part of the steel material is partially heated, a partial tunnel type or partial It is preferable to use a partial heating type induction furnace such as a transverse type or a hairpin type.

  In the continuous heat treatment apparatus according to the present invention, when the steel material is conveyed and heated by a plurality of heating furnaces, the steel material is treated by a first induction heating furnace, a combustion heating furnace using a combustion burner, Since it was made to guide and heat in order of 2 induction type heating furnaces, while heating steel materials, such as a steel slab and a steel plate, efficiently, when heating steel materials were led to a post-processing apparatus and post-processing, it was heated, for example When the steel slab is led to a post-processing device composed of a rolling device and rolled, the heated steel slab can be appropriately rolled so as to be homogeneous.

  Moreover, in the remodeling method of the continuous heat treatment apparatus according to the present invention, in the continuous heat treatment apparatus provided with only the direct-fired heating furnace that conveys and heat-treats the steel material, A first induction heating furnace is provided at a position upstream of the steel material in the conveyance direction, and a second induction heating furnace is provided at a position downstream of the direct-fired heating furnace in the conveyance direction of the steel material. Also, a continuous heating furnace in which the steel material is transported and heat-treated, and a continuous induction heating furnace is provided on either the upstream side or the downstream side in the steel material transport direction with respect to the direct fire type heating furnace. In the heat treatment apparatus, the induction heating furnace is provided at a position on the upstream side or the downstream side in the conveying direction of the steel material than the direct-fired heating furnace in which the induction heating furnace is not provided. Like continuous heat treatment equipment Rukoto can, it becomes possible to effectively utilize the existing continuous heat treatment apparatus.

1 shows a continuous heat treatment apparatus according to Embodiment 1 of the present invention, which uses a steel slab as a steel material, conveys the steel slab, and is a direct-fired heating furnace using a first induction heating furnace and a combustion burner. After continuously heating in the order of the heating furnace, the conveying direction of the steel slab heated by the guide conveyance unit is changed and led to the second induction heating furnace to be heated, and the steel slab thus heated is It is the schematic explanatory drawing which showed the state rolled by the rolling apparatus of a post-processing apparatus. The continuous heat processing apparatus which concerns on Embodiment 2 of this invention is shown, The long strip is used as steel materials, this strip is conveyed with a feed roller etc., and the combustion type | mold using a 1st induction heating furnace and a combustion burner The indirect heating furnace which is a heating furnace and the second induction heating furnace are successively heated in this order, and the strip thus heated is led to a post-treatment device such as a continuous annealing device or a plating device for post-treatment. It is the schematic explanatory drawing which showed the state. The remodeling method of the continuous heat processing apparatus which concerns on Embodiment 3 of this invention is shown, The above-mentioned with respect to the continuous heat processing apparatus provided only with the direct-fired heating furnace in the continuous heat processing apparatus shown in the said Embodiment 1 A conveying direction in which the first induction heating furnace is provided at a position upstream of the direct-fired heating furnace in the conveying direction of the steel material, and the steel piece heated by the direct-fired heating furnace is conveyed by the guide conveying unit. It is the schematic explanatory drawing which showed the state which provided the 2nd induction heating furnace in the downstream position. A remodeling method of a continuous heat treatment apparatus according to Embodiment 4 of the present invention, showing a continuous heat treatment apparatus provided with a first induction heating furnace and an open flame heating furnace in the continuous heat treatment apparatus shown in Embodiment 1 above On the other hand, it is a schematic explanatory view showing a state in which a second induction heating furnace is provided at a position on the downstream side in the transport direction in which the steel piece heated by the direct-fired heating furnace is transported by the guide transport unit is there.

  Hereinafter, a continuous heat treatment apparatus according to an embodiment of the present invention and a modification method of the continuous heat treatment apparatus will be specifically described with reference to the accompanying drawings. The continuous heat treatment apparatus and the method for remodeling the continuous heat treatment apparatus according to the present invention are not limited to those shown in the following embodiments, and can be implemented with appropriate modifications within the scope not changing the gist of the invention. is there.

(Embodiment 1)
Embodiment 1 shows the 1st example of a continuous heat processing apparatus, and in this continuous heat processing apparatus of Embodiment 1, as shown in FIG. Used, this steel piece X1 is conveyed in the short side direction orthogonal to the long side direction.

  And in this continuous heat processing apparatus, it is the direct heating type heating which is the combustion type heating furnace 20 using the 1st induction heating furnace 10 and the combustion burner 21 toward the conveyance direction downstream side which conveys the said steel slab X1. A furnace 20A is continuously provided, and the steel slab X1 is sequentially introduced into the first induction heating furnace 10 and the direct-fired heating furnace 20A to be conveyed, and the steel slab X1 is supplied to the first induction furnace. Heating is performed sequentially in the heating furnace 10 and the direct-fired heating furnace 20A.

  Here, as the first induction heating furnace 10, an overall heating type induction type such as a tunnel type so that the entire steel piece X 1 introduced into the first induction heating furnace 10 is quickly heated. A heating furnace is used.

  Further, in the above-described direct-fired heating furnace 20A, a plurality of combustion burners are provided on both sides of the furnace wall 21 provided along the conveying direction of the steel slab X1 with a required interval in the conveying direction of the steel slab X1. 22, the fuel is burned by each combustion burner 22, and the steel slab X <b> 1 heated through the first induction furnace 10 is further heated.

  Further, the steel piece X1 heated through the first induction heating furnace 10 and the direct-fired heating furnace 20A in this way is conveyed through the first induction heating furnace 10 and the direct-fired heating furnace 20A. A plurality of conveying rollers 41 are connected to the first induction heating furnace 10 and the direct-fired heating furnace as a guide conveying unit 40 that conveys the steel slab X1 in a direction crossing the conveying direction of X1 and guides it to the second induction heating furnace 30. It arranges along the direction orthogonal to the conveyance direction of the steel slab X1 conveyed through 20A.

  And after the steel slab X1 heated as mentioned above by each said conveyance roller 41 is guide | induced to the 2nd induction heating furnace 30, and the said steel slab X1 is heated in the 2nd induction heating furnace 30, this, The steel strip X1 heated by the second induction heating furnace 30 is rolled in the rolling apparatus 51, which is led to a rolling apparatus 51 that is a post-processing apparatus 50 provided on the downstream side of the second induction heating furnace 30. Yes.

  Here, before the steel slab X1 heated through the first induction heating furnace 10 and the direct-fired heating furnace 20A as described above is guided to the rolling device 51 by the respective conveying rollers 41, as described above. When the heated steel slab X1 is led to the 2-induction heating furnace 30 and heated, the temperature of the surface of the heated steel slab X1 and each end face is in the middle of guiding the heated steel slab X1 to the rolling device 51 by each conveying roller 41. Even if the temperature decreases, the surface and each end surface of the steel slab X1 whose temperature has decreased in this way are quickly heated in the second induction furnace 30 and the entire steel slab X1 is heated sufficiently uniformly. In this state, the steel slab X1 that has been guided to the rolling device 51 and rolled and heated and can be appropriately rolled so as to be homogeneous. Here, as the second induction heating furnace 30, a partial heating type induction heating furnace such as a partial transverse type that partially heats the surface and each end face of the steel slab X1 whose temperature is lowered is used. I am doing so.

  In the first embodiment, the rolling device 51 is provided as the post-processing device 50. However, the post-processing device 50 to be used is not limited to the rolling device 51, and other devices can be provided.

  Further, in the first embodiment, the first induction heating furnace 10 and the direct-fired heating furnace 20 </ b> A are continuously provided with respect to a plurality of transfer rollers 41 that are the guide transfer unit 40. However, a plurality of the first induction heating furnace 10 and the direct-fired heating furnace 20 </ b> A are continuously provided for the plurality of transport rollers 41 which are the guide transport unit 40. The steel pieces X1 heated through the first induction heating furnace 10 and the direct-fired heating furnace 20A provided in plurality as described above are sequentially guided to the second induction heating furnace 30 by the transfer roller 41. The steel slab X1 heated in the second induction furnace 30 in this way can be guided to the rolling device 51 in order and rolled.

(Embodiment 2)
Embodiment 2 shows a second example of the continuous heat treatment apparatus. In the continuous heat treatment apparatus of Embodiment 2, as shown in FIG. The obtained long strip X2 is used, and this strip X2 is conveyed in the longitudinal direction via a feed roller (not shown) or the like.

  And in this continuous heat processing apparatus, it is the 1st induction type heating furnace 10 and the combustion type heating furnace 20 using the combustion burner 21 toward the downstream from the conveyance direction upstream of the said strip X2, Comprising: Radiant tube An indirect heating furnace 20 </ b> B for burning fuel in the inside (not shown) and a second induction heating furnace 30 are provided continuously, and a post-processing device 50 is provided downstream of the second induction heating furnace 30. A continuous annealing device 52 is provided. In addition, the post-processing apparatus 50 provided in the downstream of the 2nd induction heating furnace 30 is not restricted to the said continuous annealing apparatus 52, For example, it is also possible to provide a plating apparatus (not shown).

  Here, as the first induction heating furnace 10 and the second induction heating furnace 30, the entire strip X2 led to the first induction heating furnace 10 and the second induction heating furnace 30 is quickly heated. As described above, an induction heating furnace of an overall heating type such as a tunnel type is used.

  In the indirect heating furnace 20B, a plurality of combustion burners 22 are provided on the furnace wall 21 provided along the transport direction of the strip X2 so as to have a required interval in the transport direction of the strip X2. Each combustion burner 22 burns fuel in a radiant tube (not shown) in the furnace, further heats the strip X2 heated through the first induction furnace 10, and in that state, the second induction heating described above. It is led to the furnace 30 to further heat the strip X2. When the fuel is burned in the radiant tube (not shown) in the furnace using the indirect heating furnace 20B in this way, the strip X2 heated through the first induction furnace 10 is burned. However, it becomes possible to prevent oxidation by direct contact with the combustion exhaust gas.

  And the strip X2 heated through the 1st induction heating furnace 10, the indirect heating furnace 20B, and the 2nd induction heating furnace 30 in this way was provided in the downstream of the 2nd induction heating furnace 30. The strip X2 heated in the continuous annealing apparatus 52 as described above is continuously annealed by being introduced into the annealing apparatus 52.

(Embodiment 3)
Embodiment 3 shows an example in which an existing continuous heat treatment apparatus as shown in FIG. 3 is modified to the continuous heat treatment apparatus shown in Embodiment 1 shown in FIG.

  Here, in the existing continuous heat treatment apparatus in the third embodiment, only the direct-fired heating furnace 20A in the continuous heat treatment apparatus shown in the first embodiment is provided, and the first induction heating is performed. The furnace 10 and the second induction heating furnace 30 are not provided.

  For this reason, in this Embodiment 3, while providing the 1st induction heating furnace 10 similar to the said Embodiment 1 in the position of the conveyance direction upstream of the said slab X1 rather than the said direct-fire-type heating furnace 20A. The part of the plurality of transport rollers 41 that changes the transport direction of the steel slab X1 heated by the direct-fired heating furnace 20A and transports it in the direction of the rolling device 51 is the same as that of the first embodiment. The second induction furnace 30 is provided at a position upstream of the rolling device 51 in the transfer direction of the steel slab X1, and the steel slab X1 heated by the second induction furnace 30 is guided to the rolling device 51. In the rolling device 51, the steel slab X1 heated by the second induction furnace 30 is rolled.

  In this way, the existing continuous heat treatment apparatus in which the first induction heating furnace 10 and the second induction heating furnace 30 are not provided is remodeled, and the continuous heat treatment apparatus shown in the first embodiment is It is possible to obtain a continuous heat treatment apparatus that exhibits the same effects, and it is possible to effectively use an existing continuous heat treatment apparatus.

(Embodiment 4)
The fourth embodiment shows an example in which an existing continuous heat treatment apparatus as shown in FIG. 4 is modified to the continuous heat treatment apparatus shown in the first embodiment shown in FIG.

  Here, in the existing continuous heat treatment apparatus in the fourth embodiment, the first induction heating furnace 10 and the direct-fired heating furnace 20A in the continuous heat treatment apparatus shown in the first embodiment are provided. However, the second induction heating furnace 30 is not provided.

  For this reason, in this Embodiment 4, it changes in the conveyance direction of the steel slab X1 heated by the said direct-fire type heating furnace 20A, and it is in the part of the said some conveyance roller 41 made to convey in the direction of the rolling mill 51. The second induction heating furnace 30 similar to that of the first embodiment is provided at a position upstream of the rolling device 51 in the transfer direction of the steel slab X1, and the steel slab heated by the second induction heating furnace 30. X1 is guided to the rolling device 51, and the steel piece X1 heated by the second induction furnace 30 in the rolling device 51 is rolled.

  If it does in this way, the existing continuous heat processing apparatus in which the 2nd induction heating furnace 30 is not provided will be remodeled, and the continuous heat processing which has the same operation effect as the continuous heat processing apparatus shown in the above-mentioned Embodiment 1 will be shown. An apparatus can be obtained and an existing continuous heat treatment apparatus can be used effectively.

DESCRIPTION OF SYMBOLS 10: 1st induction heating furnace 20: Combustion heating furnace 20A: Direct-fired heating furnace 20B: Indirect heating heating furnace 21: Furnace wall 22: Combustion burner 30: 2nd induction heating furnace 40: Guide conveyance part 41 : Conveying roller 50: Post-processing device 51: Rolling device 52: Continuous annealing device X: Steel material X1: Steel slab X2: Strip

Claims (6)

  In a continuous heat treatment apparatus that conveys steel materials and heats them with a plurality of heating furnaces, the steel materials are processed in the order of a first induction heating furnace, a combustion heating furnace using a combustion burner, and a second induction heating furnace. A continuous heat treatment apparatus which is conveyed and heated.   The continuous heat processing apparatus of Claim 1 WHEREIN: The post-processing apparatus which post-processes the steel materials heat-processed by the 2nd induction heating furnace in the conveyance direction of steel materials rather than the said 2nd induction heating furnace. A continuous heat treatment apparatus provided.   The continuous heat treatment apparatus according to claim 1 or 2, further comprising a guide conveyance unit that changes a conveyance direction of the steel material heated in the combustion-type heating furnace and guides the steel material to the second induction-type heating furnace. The continuous heat processing apparatus characterized by the above-mentioned.   The continuous heat treatment apparatus according to any one of claims 1 to 3, wherein the combustion-type heating furnace is a direct-fired heating furnace or an indirect heating-type heating furnace. apparatus.   In a continuous heat treatment apparatus provided with a direct-fired heating furnace that conveys and heat-treats a steel material, the first induction-type heating furnace is disposed at a position upstream of the direct-fired heating furnace in the transport direction of the steel material. A remodeling method for a continuous heat treatment apparatus, characterized in that a second induction heating furnace is provided at a position downstream of the direct-fired heating furnace in the conveying direction of the steel material. In a continuous heat treatment apparatus in which an induction heating furnace is provided on either the upstream side or the downstream side in the conveyance direction of the steel material from the direct fire type heating furnace that conveys and heat-treats the steel material. A remodeling method for a continuous heat treatment apparatus, characterized in that an induction heating furnace is provided at a position upstream or downstream in the conveying direction of a steel material relative to a direct heating furnace in which no induction heating furnace is provided.

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