JP3999935B2 - Soaking roll and energizing heating device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a soaking roll and an electric heating device. More specifically, for example, the present invention relates to a temperature equalizing roll and an electric heating device used when a heat treatment such as quenching or annealing is performed on a material to be heated such as a steel strip.
[0002]
[Prior art]
Conventionally, as an energizing heating device for applying heat treatment such as quenching or annealing to a heated strip material such as a strip-shaped steel plate, the continuously fed heated strip material is separated along a feeding path by a predetermined interval. There is known an energization heating apparatus for bringing a heated belt material into contact with a pair of rolls arranged in contact with each other and applying a voltage between energization rolls of the pair of rolls.
[0003]
In the energization heating apparatus, the pressing rolls of the pair of rolls are heated by the heated band material that has been heated to high temperature by energization heating. At this time, the axial length of the pressing roll is the width of the heated band material. Therefore, the contact portion near the center of the pressing roll is directly and intensively heated, and the non-contact portions near both ends of the pressing roll are not heated so much. Accordingly, even if the diameter dimension at the time of manufacture of the pressing roll is perfect, a temperature deviation occurs in the axial direction during operation, and a diameter deviation (hereinafter referred to as a thermal crown) occurs.
[0004]
In this way, when a thermal crown occurs on the holding roll, contact failure occurs between the energizing roll and the heated strip, particularly at the edge of the heated strip where the gap between the two becomes large. Sparks are generated. And by this spark, a spark wrinkle enters the surface of the energizing roll and the surface of the heated belt material, and in particular, the spark wrinkle of the energizing roll has a problem that it continuously causes transfer wrinkles in the heated belt material thereafter. . As a result, this causes a decrease in the life of the energizing roll and a decrease in the quality of the heated belt material.
[0005]
Therefore, in recent years, as an energization heating device capable of preventing the occurrence of sparks between the energization roll and the heated belt member, the shell thickness of the press roll is reduced, and flattening due to elastic deformation in the radial direction of the shell is performed. There has been proposed an energization heating apparatus that can ensure contact between a presser roll and a heated belt material and contact between a heated belt material and an energized roll using Japanese Patent Application Laid-Open No. 5-295422. Gazette or JP-A-5-36467).
[0006]
When such an electric heating device is used, it is possible to ensure the contact between the press roll and the heated belt material and the contact between the heated belt material and the conductive roll. Since the platen part of the plate is overheated, a thermal crown is generated in the presser roll itself, and contact between the presser roll and the heated belt material is not secured, and a spark is generated between the energizing roll and the edge part of the heated belt material. May occur.
[0007]
Therefore, in order to ensure the contact between the press roll and the heated strip, the shell thickness of the press roll is reduced, the press roll is pressed with the backup roll, and the thermal crown of the press roll shell is deformed. Thus, a method of bringing it into close contact with the heated material can be considered.
[0008]
However, when such a method is adopted, excessive stress is applied to the shell of the press roll to cause damage to the shell or deformation of the shell of the press roll, resulting in the shape of the material to be heated. There is a risk of worsening.
[0009]
As a method for preventing the deterioration of the shape of the heated strip material, Japanese Patent Application Laid-Open No. 9-260028 has a metal shell with a built-in heat pipe, and a flexible material is provided between the metal shell and the shaft. There is a method using a roll (shell built-in type roll). This roll can reduce the thermal crown of the roll by the temperature equalizing action in the roll axial direction of the heat pipe. In addition, a flexible material is provided between the shell and the shaft, and plays a role in flexibly bringing the shell into close contact with the heated belt material and holding the shell on the shaft.
[0010]
However, in this method, since the heat pipe is built in the shell, the capacity of the heat pipe is limited, so that the temperature equalizing action is limited, and there is a possibility that sufficient temperature equalization cannot be obtained. In addition, the flexible material provided between the shell and the shaft is permanently set due to compression with use, and there is a risk that a gap will be generated between the shell and the flexible material, causing it not to adhere to the heated belt material. .
[0011]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described conventional technology, and improves the temperature uniformity, reduces the thermal crown of the roll, and the temperature equalization roll that allows the roll to be optimally adhered to the heated belt material and the temperature equalization roll. An object of the present invention is to provide an energization heating device using a roll.
[0012]
[Means for Solving the Problems]
The temperature equalizing roll according to claim 1 of the present invention includes a heat transfer liquid that repeats evaporation and condensation inside a hollow roll body, and a plurality of water-cooled tubes extending in the roll axis direction of the roll body. A water cooling tube bundle is provided, both ends of the water cooling tube bundle are connected to water chamber portions provided at both ends of the roll body to provide a cooling water channel, and crowning is performed in the roll axial direction of the outer surface of the roll body. It is characterized by being provided.
[0013]
Moreover, the energizing heating apparatus according to claim 2 of the present invention is a roll pair composed of a pressing roll and an energizing roll, in which the heated belt material continuously fed is arranged at a predetermined interval along the feeding path. A heating device for energizing and heating the heated strip material between the pair of rolls, the press roll contacting the heated strip material at least in a high temperature region of the heated strip material, and The temperature equalizing roll according to claim 1 is used for at least one of the energizing rolls.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a temperature equalizing roll and an electric heating device of the present invention will be described with reference to the accompanying drawings.
[0015]
The temperature equalizing roll of the present invention can be applied to at least one of a pressing roll and an energizing roll in the energization heating device, but in this embodiment, a case where it is applied to a pressing roll will be described.
[0016]
FIG. 1 is a schematic explanatory view showing an embodiment of the electric heating apparatus of the present invention. In FIG. 1, current-carrying rolls 2 and 3 are arranged on the lower surface of the heated belt material 1. On the upper part of the current-carrying rolls 2 and 3, presser rolls 4 and 5 that are opposed to the current-carrying rolls 2 and 3, respectively, are arranged with the heated belt material 1 interposed therebetween. The heated strip 1 to be continuously fed is brought into contact with a pair of rolls arranged at a predetermined interval along the feeding path. Such a roll pair is constituted by an energizing roll 2 and a pressing roll 4, and an energizing roll 3 and a pressing roll 5.
[0017]
The energizing rolls 2 and 3 and the pressing rolls 4 and 5 are rotatable about the shafts 6, 7, 8 and 9, respectively. The energizing rolls 2 and 3 are continuous in the direction of arrow A of the heated belt material 1. In some cases, the motor is driven to rotate in synchronization with the feeding.
[0018]
An energizing roll 3 that is in contact with the heated band material 1 in a high temperature region of the heated band material 1 and a pressing roll 5 that is opposed to the heated band material 1 are in contact with a backup roll 11 and are backed up. The press roll 5 is pressed by the roll 11, and the press roll 5 is deformed so as to conform to the shape of the minute thermal crown generated in the energizing roll 3 and the heated strip 1, and the press roll 5 and the heated strip Contact with 1 is ensured.
[0019]
In the present invention, as shown in FIG. 1, even in a low temperature region of the heated strip 1, the energizing roll 2 contacting the heated strip 1 and the heated strip 1 are sandwiched as necessary. The facing pressing roll 4 may be in contact with the backup roll 10. In this case, the pressing roll 4 is pressed by the reduction by the backup roll 10, and the contact between the pressing roll 4 and the heated belt material 1 is further ensured as in the high temperature region.
[0020]
In FIG. 1, an annular transformer 12 is disposed between the energizing roll 2 and the energizing roll 3 on the outer periphery of the heated belt material 1. The annular transformer 12 includes an annular iron core 13 in which a silicon steel plate having properties suitable as a magnetic path is formed in a rectangular annular shape and laminated to a predetermined length, and a primary coil wound along the inner and outer circumferences of the annular iron core 13. 14. The primary coil 14 of the annular transformer 12 is connected to an AC power supply 15 having a power control switch.
[0021]
The current-carrying rolls 2 and 3 have power receiving portions on the shafts 6 and 7, for example, and the sliders 16 and 17 are slidably contacted with the power receiving portions, respectively. A conductive member (bus bar) 18 is installed between the slider 16 and the slider 17, and the energizing roll 2 and the energizing roll 3 are electrically connected. For the conductive member 18, a good conductive material such as a copper material having a predetermined width and thickness is used.
[0022]
The relationship between the electric resistance R1 of the heated strip 1 and the electric resistance R2 of the conductive member 18 between the energizing roll 2 and the energizing roll 3 is set to satisfy R1 >> R2. The conductive member 18 is disposed close to and above the annular transformer 12 and the heated belt material 1 at substantially equal intervals, is integrally coupled in the vicinity of the current-carrying rolls 2 and 3, and is connected to the sliders 16 and 17. Yes.
[0023]
In the present embodiment, the method of arranging the annular transformer 12 around the outer periphery of the heated strip 1 and supplying power has been described. However, the present invention is not limited to this, and the energizing rolls 2, 3 Electricity can also be supplied directly from the outside.
[0024]
FIG. 2 is a schematic cross-sectional view of the pressing roll used in the electric heating apparatus of the present invention in a direction perpendicular to the axis, and FIG. 3 is a cross-sectional view taken along the line BB of FIG.
[0025]
The press roll 5 according to the present embodiment has a roll main body (shell) 21 having both ends closed and a hollow inside, a heat transfer liquid 22 enclosed in the roll main body 21, and the roll main body 21. A water chamber portion 24 provided in a closing member (partition wall) 21a at both ends and a water cooling tube bundle composed of a plurality of water cooling tubes 23 disposed in both water chamber portions 24, and holds the heat transfer liquid 22 And a closed roll structure. During operation, water flows from the tube inserted through one shaft to the tube inserted through the other shaft via the water chamber 24, the water cooling tube 23, and the water chamber 24 (see arrow F direction). The heat carrier liquid 22 is sealed after the inside of the roll body is vacuum processed, and repeats evaporation and condensation. A crowning C is formed in the roll axis direction on the outer surface of the roll body 21.
[0026]
The material of the roll body is ordinary steel or low alloy steel. For example, the thickness of the roll center is 16 mm, and the desirable value of the crowning C is a 120 μm sine curve (the vertex of the roll center is 90 degrees, the left and right roll edges are 0 degrees and 180 degrees (zero point)). Sine curve whose height difference is 120 μm. As the heat carrier liquid, water, chlorofluorocarbon or naphthalene can be used. The heat carrier liquid evaporates in a high temperature region on the heated zone side, and the generated steam is cooled by the water cooling pipe 23, condensed and returned to the liquid, and the heat of the roll is released.
[0027]
As the pressing roll 4 and the energizing rolls 2 and 3, those used in an energizing heating device can be applied. One example is a conductive roll having an outer diameter of about 300 to 600 mm made of a material such as ordinary steel or low alloy steel.
[0028]
In the electric heating apparatus configured as described above, when a primary voltage is applied from the AC power supply 15 to the primary coil 14 of the annular transformer 12 as shown in FIG. 1, it is inserted into the ring of the primary coil 14. Since the heated band material 1 functions as a secondary coil, a secondary voltage is induced in the heated band material 1 and the heated band material 1 is energized and heated.
[0029]
The presser roll 5 has high temperature uniformity because the entire roll body is a heat pipe. That is, it is said that the temperature equalization performance of the heat pipe, that is, the heat transfer capability is proportional to the cube of the diameter, and the conventional roll with a built-in shell has a limit, but the entire roll body of the press roll 5 in this embodiment is limited. Since it becomes a heat pipe, extremely large temperature equalizing performance can be obtained, and the thermal crown can be reduced.
[0030]
In addition, in the case of a conventional shell built-in type roll, the amount of compression set differs in the roll axis direction and the circumferential direction, resulting in variations in the holding force of the shell, and the reduction force of the heated belt material by the shell. Although there is a risk of contact failure due to variations, the pressure roll 5 in the present embodiment is less likely to generate pressure variations because the heated belt material is reduced only by the elasticity of the roll body.
[0031]
Furthermore, because the roll body is supported by a blocking member provided with a water chamber, excessive pressure is applied to the edge of the heated belt material, but since the crowning is formed on the outer surface, excessive pressure is applied. It can be avoided and can be brought into close contact with the material to be heated by the optimal deformation of the roll body.
[0032]
In this embodiment, the press roll in the high temperature region is a soaking roll, but in the present invention, the press roll in the low temperature region is not limited to this. You can also.
[0033]
Further, in the present invention, when heat treatment is performed on the heated strip 1, in order to prevent an impact force from being generated between the backup roll 11 and the pressing roll 5 when the pressing roll 5 is opened and closed in a high temperature region. The pressing roll 5 is preferably connected to the backup roll 11. Thus, as means for connecting the pressing roll 5 and the backup roll 11, for example, as shown in FIG. 4 which is a schematic explanatory view in the plate passing direction, the bearing 25 of the shaft 9 of the pressing roll 5 and the backup roll For example, means for connecting the bearing 27 of the shaft 26 of the roll 11 with a connecting spring 28 such as a leaf spring or a spring can be used. It should be noted that when the press roll 5 and the backup roll 11 are connected and released from the heated belt material, adjustment is made so that a pressure of about 2.9 N / mm or more is always applied between them. preferable.
[0034]
The pressing roll 5 and the backup roll 11 can be opened and closed by moving the pressing roll 5 and the backup roll 11 up and down by a cylinder 29 or the like provided above the shaft 26 of the backup roll 11.
[0035]
In this embodiment, when the press roll is pressed with the backup roll, the roll body of the press roll is deformed and brought into close contact with the heated belt material, even if the stress applied from the backup roll to the roll body of the press roll is small, The contact between the press roll and the heated belt material can be secured, and since the stress applied to the press roll from the backup roll may be small, the roll body of the press roll may be damaged, or the shape of the heated belt material Will not cause any deterioration.
[0036]
In the present embodiment, even in the low temperature region of the heated belt material, as shown in FIG. 1, when the backup roll 10 is provided in contact with the pressing roll 4 as necessary, the same as in the high temperature region. In addition, it is preferable that the pressing roll 4 and the backup roll 10 are connected to prevent an impact force from being generated between the backup roll 10 and the pressing roll 4. As a means for connecting the pressing roll 4 and the backup roll 10, there is a means for connecting with a connecting spring as shown in FIG. 4 as in the case of the high temperature region.
[0037]
Next, the present invention will be described based on examples, but the present invention is not limited to such examples.
[0038]
Examples and Comparative Examples 1-2
As the material of the roll body, a roll body having a roll outer diameter of φ350 mm, a roll surface length of 1400 mm, a shell thickness of 16 mm and a crowning amount of 120 μm (sine curve) is produced using low carbon steel. Inside, 26 water-cooled tubes were provided, and a holding roll R enclosing chlorofluorocarbon was prepared as a heat transfer liquid. Low carbon steel was also used as the material of the shaft connected to the closing members at both ends of the roll body. Similarly, a roll (shell built-in type roll) R1 in which a conventional shell incorporating a heat pipe is held by a flexible material was also prepared.
[0039]
Next, an energization heating apparatus shown in FIG. 1 in which a connecting spring is connected between the pressing roll and the backup roll was prepared, and the pressing roll R was incorporated as a pressing roll. The heating length between the roll pair in the high temperature region and the low temperature region of Kotokino steel plate is 2000 mm, and the heating temperature is set to 850 ° C. and the linear current density is set to 12 A / mm. 1000 mm, thickness 0.3 mm).
[0040]
Next, the relationship between the distance from the roll center of the pressing roll R (the distance in the sheet width direction of the steel sheet) and the surface temperature of the roll was examined (Example). Similarly, a built-in shell type roll R1 was incorporated as a pressing roll, and the relationship between the distance and temperature at this time was also examined (Comparative Example 1).
[0041]
The result is shown in FIG. In FIG. 5, from the surface temperature of the roll at the center portion of the plate width and the end portion of the plate width, in the case of the pressing roll R of this embodiment, the temperature deviation in the plate width direction is about 5 ° C. In the case of the roll with built-in shell R1 of Comparative Example 1, a deviation of about 15 ° C. was produced.
[0042]
Therefore, it can be seen that the temperature deviation in the example is much smaller than that in Comparative Example 1.
[0043]
Next, a pressing roll R2 that is made of the same material as the pressing roll R of the above embodiment but does not process the crowning was prepared. Then, in order to investigate the influence of the presence or absence of the roll crown using the same electric heating device, the relationship between the distance from the roll center (distance in the plate width direction of the steel plate) and the surface temperature of the roll was examined in the same manner as in the previous example. (Comparative Example 2).
[0044]
The result is shown in FIG. As shown in FIG. 6, in the case of the press roll R2 having no kurunning, the temperature at the end of the steel plate near ± 400 mm from the roll center is high, and the heat input from the steel plate is increased due to high roll reduction. . Moreover, since the rolling force of the roll center portion is low, the temperature is low. By observing the appearance of the pressing roll R2 at this time, the end of the steel plate was rolled by rolling and a large shape defect occurred, and at the roll center portion of the steel plate, the rolling resistance decreased and the contact resistance decreased. A spark occurred. On the other hand, the press roll R to which crowning was applied had no shape defect and no spark was observed.
[0045]
【The invention's effect】
As described above, according to the present invention, the temperature uniformity of the roll is increased, the thermal crown of the roll is reduced, and the roll can be optimally adhered to the heated belt material, thereby inducing the deterioration of the shape of the heated belt material. There is no.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view showing an embodiment of an electric heating apparatus of the present invention.
FIG. 2 is a schematic cross-sectional view in a direction perpendicular to the axis of a pressing roll used in the electric heating device of the present invention.
FIG. 3 is a schematic cross-sectional view in the axial direction (B-B line) of a pressing roll used in the electric heating apparatus of the present invention.
FIG. 4 is a schematic explanatory view showing another example of a pressing roll and a backup roll in the plate passing direction of the electric heating device of the present invention.
FIG. 5 is a diagram showing the relationship between the distance from the roll center (distance in the plate width direction of the steel plate) and the surface temperature of the roll in the press roll in the present invention and the conventional press roll.
FIG. 6 is a diagram showing the relationship between the distance from the roll center (distance in the plate width direction of the steel sheet) and the surface temperature of the roll depending on whether or not the pressing roll is crowned.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heated strip material 2, 3 Current supply roll 4, 5 Pressing roll 10, 11 Backup roll 21 Roll main body 21a Closure member 22 Heat transfer liquid 23 Water cooling pipe 24 Water chamber part C Crowning

Claims (2)

Inside the hollow roll body, a heat transfer liquid that repeats evaporation and condensation is sealed, and a water cooling tube bundle consisting of a plurality of water cooling tubes extending in the roll axial direction of the roll body is disposed, and both ends of the water cooling tube bundle are arranged. Is connected to water chambers provided at both ends of the roll body to provide a cooling water channel, and is provided with crowning in the roll axial direction of the outer surface of the roll body. The heated belt material continuously fed is brought into contact with a pair of rolls composed of a pressing roll and an energizing roll arranged at a predetermined interval along the feeding path, and the heated belt material is interposed between the roll pairs. An electric heating apparatus for electrically heating an object, wherein the temperature equalizing unit according to claim 1 is applied to at least one of the pressing roll and the electric roll in contact with the heated belt material at least in a high temperature region of the heated belt material. An energization heating apparatus using a roll.

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