JP5551504B2 - Steel plate end face heating device - Google Patents

Description

  The present invention relates to a post-processing technique after a steel plate such as a thick steel plate is cut by a mechanical cutting method such as shearing with a shear. In particular, the present invention relates to an end face heating device suitable for preventing the occurrence of cross-sectional cracks caused by residual hydrogen in steel, which occurs at the time of online cutting of a high-strength steel plate manufactured through accelerated cooling by a cooling device provided on a transfer line.

In recent years, as a manufacturing process for high-strength thick steel plates, there has been an increase in online processes in which continuous cast slabs are inserted into a heating furnace as hot pieces and manufactured in a short time by hot rolling and accelerated cooling in online equipment. Yes. Since the online process does not include offline processing, it is a process-saving process, and has an advantage in terms of reducing environmental burden and increasing production efficiency.
On the other hand, in such an online process, sufficient time for diffusing and releasing hydrogen remaining in the steel sheet from the casting stage cannot be secured. For this reason, there is also a problem that hydrogen tends to remain in the steel sheet and hydrogen defects are likely to occur. In particular, a higher strength material is more sensitive to hydrogen defects and tends to cause internal defects and cross-sectional cracks. These defects are a kind of delayed fracture due to hydrogen in steel, center segregation, shear surface residual stress, etc., and the vicinity of the segregation part with a thickness of 1/2 part (center part) or shear as shown in FIG. This causes a crack starting from the rear cross-section 50. In particular, prevention of these hydrogen defects is required for products with strict quality requirements such as thick steel plates for line pipes.

  Conventionally, it is known that steel sheet slow cooling is effective as a method for preventing the above-described internal defects and cross-sectional cracks. Steel sheet slow cooling is performed by removing the steel sheet after rolling and accelerated cooling from the line before or after cutting with a pile crane, etc., and piled up in a slow cooling pit or an empty yard and kept warm. It is a method that promotes the diffusion and release of water. As a technique related to steel sheet slow cooling, for example, Patent Document 1 discloses a steel sheet stacking method for performing efficient slow cooling particularly at the end of a steel sheet. Patent Document 2 discloses a method for improving the cooling efficiency by placing a steel plate in a slow cooling box and then reducing the pressure.

On the other hand, as a method that does not rely on slow cooling, as disclosed in Patent Document 3 and Patent Document 4, for example, there is a method of suppressing the occurrence of hydrogen cracking in the cut surface by rapidly heating the cut surface. Patent Document 3 discloses that the residual stress of the cut surface is reduced by _{raising the} temperature of the cut surface to 450 ° C. to A _c1 temperature. Patent Document 4 discloses that the residual stress of the cut surface is reduced by _{raising the} temperature of the cut surface to the A _c1 temperature or higher and taking into account the residual stress reduction effect due to phase transformation. Any of these methods is effective for suppressing cross-sectional cracking.

Japanese Patent Laid-Open No. 10-203212 JP 2001-303127 A JP 2007-245261 A JP 2008-184636 A

The steel sheet annealing described above is effective in promoting the diffusion and release of hydrogen in the steel sheet because the steel sheet is kept at a higher temperature for a longer time as the annealing start temperature is higher.
However, in recent years, with the increase in strength of thick steel plates, a structure-building method that requires the formation of a structure at a low temperature (such as the Ms point or less) such as martensite has been frequently used. In such a case, the annealing start temperature cannot be made higher than the above temperature in terms of material design. In general, as shown in FIG. 16, the diffusion coefficient of hydrogen in the steel sheet rapidly decreases as the temperature decreases. In addition, as shown in FIG. 17, the higher the strength material, the lower the diffusion coefficient of hydrogen. Therefore, it is difficult to lower the annealing start temperature in order to obtain a sufficient annealing effect with a high-strength material. Under such circumstances, it is necessary to manage the annealing temperature of the high-strength material in a temperature range narrower than that of a general material.

  However, in the usual slow cooling method that only stacks steel plates at a predetermined temperature, the dimensions of the thick steel plates are not uniform, so it is very difficult to manage the slow cooling temperature so that it has a uniform temperature history. Have difficulty. Moreover, when the dimension of a thick steel plate is non-uniform | heterogenous, since the stacking which is disclosed by patent document 1 cannot be performed, the technique of patent document 1 obtains the edge part heat insulation effect which was aimed at. It is also difficult. In addition, the method of providing a completely sealed annealing field as in Patent Document 2 has a problem that a large amount of steel sheets cannot be processed in operation. For this reason, it is very difficult to manage the annealing temperature in a uniform temperature history. Therefore, the annealing temperature is usually set to a narrower temperature range in consideration of variations in temperature history during annealing. In many cases, it is not used for stable production.

  On the other hand, according to the methods of Patent Document 3 and Patent Document 4, it is possible to suppress the occurrence of cross-sectional cracking only by heat treatment of the cut surface without performing slow cooling of the steel plate that is difficult to control temperature as described above. However, these patent documents only specify a target cut surface temperature, and do not disclose a specific method for heating the cut surface to a target temperature range.

  This invention pays attention to the above points, and it aims at providing the end surface heating apparatus which can heat the cut surface of a steel plate more reliably.

In order to solve the above problems, the invention described in claim 1 of the present invention is an end surface heating device for heating an end surface of a cut steel sheet,
A heating section of an induction heating device disposed opposite to the end face to be heated; an advancing / retreating mechanism for moving the heating section disposed opposite to the end face forward and backward with respect to the end face; a heating section advanced by the advancing / retreating mechanism; and a steel plate end face Adjusting the position of the heating unit with respect to the end face so that the distance is within the preset target proximity distance range, and the adjustment means so that the distance from the end face is within the target proximity distance range. an adjustable state, the heating unit which is disposed opposite to the end face, and a moving mechanism for moving in one direction which is set in advance along the end surface, along the moving direction of the heating unit by the moving mechanism In the direction, the length of the heating part is shorter than the length of the end face of the steel plate .

Next, the invention described in claim 2 is provided with a pair of guide members arranged to sandwich the heating unit in the moving direction of the heating unit by the moving mechanism with respect to the configuration described in claim 1.
The advancing / retreating mechanism allows the heating part to advance and retreat by advancing and retreating a support part that supports the heating part, and each guide member protrudes from the support part toward the end surface of the steel plate, from the heating part. also have a rolling portion to the distal portion in proximity to the end face, further, as the adjusting means, it is characterized in further comprising a protrusion amount changing means for changing the amount of protrusion of the guide member relative to the support section .

Next, the invention described in claim 3, to the structure according to claim 2, said adjustment means includes distance detection means further detecting the distance between the heating portion and the end face, the said distance detecting means e Bei a projection amount adjusting means for adjusting the amount of protrusion of the guide member through the protrusion amount changing means in a direction within the range of the target proximity distance detected distance is preset, and the distance detecting means, A pair of displacement sensors arranged across the heating unit in a moving direction of the heating unit by the moving mechanism, and detecting a distance between the heating unit and the end face from detection values of the pair of displacement sensors ; It is a feature.

Next, invention of Claim 4 restrains the displacement of the said steel plate conveyed to the position which heat-processes an end surface with respect to the structure described in any one of Claims 1-3. A plate pressing device is provided.
Next, in the invention described in claim 5, with respect to the configuration described in any one of claims 1 to 4, the heating unit is arranged in the middle of a conveyance line for conveying the steel sheet, and the heating is performed. And a retracting mechanism for retracting the portion upward or downward with respect to the transport line.

Next, the invention described in claim 6, the cut steel sheet, on the way in a state of temporarily stopping the conveying line of the steel sheet, the heating portion of the induction heating device, is brought close to the steel plate end face, the In a state where the position of the heating unit can be adjusted so that the distance from the end surface of the steel sheet falls within the range of the target proximity distance set in advance , the steel plate is moved in parallel along the end surface in one direction set in advance. An end surface heating device for a steel sheet is provided, wherein the end surface is induction-heated, and the length of the heating section is shorter than the length of the end face of the steel sheet in a direction along the moving direction of the heating section. .

According to the present invention, it is possible to heat the cut surface of the steel sheet more reliably.
For example, since it is possible to effectively suppress the occurrence of cracks in the cut surface after cutting the steel sheet by an on-line cutting method such as shear shearing, hydrogen removal performed before the steel sheet cutting operation is performed. Therefore, slow cooling is not necessary. As a result, for example, after cooling by a cooling device provided on the steel sheet conveyance line, it is possible to continuously cut on-line and manufacture a large amount of high-strength thick steel sheet with high productivity.

It is a schematic diagram explaining the end surface heating apparatus which concerns on 1st Embodiment based on this invention. It is a figure explaining the movement along the end surface in the heating coil of the end surface heating apparatus which concerns on 1st Embodiment based on this invention. It is a figure for demonstrating the end surface heating apparatus which concerns on 2nd Embodiment based on this invention. It is a figure for demonstrating the end surface heating apparatus which concerns on 3rd Embodiment based on this invention. It is a top view which shows the state which the steel plate skewed. It is a figure which shows the relationship between the skewed steel plate, a heating coil, and a support roll. It is a figure which shows the process example of a protrusion amount adjustment means. It is a figure which shows the board pressing apparatus which concerns on 4th Embodiment based on this invention. It is a figure which shows the example of the curvature which generate | occur | produced in the steel plate. It is a figure for demonstrating the end surface heating apparatus which concerns on 5th Embodiment based on this invention. It is a figure which shows the case where it retracts | saves in the direction over a conveyance line. It is a figure for demonstrating the operation example of the end surface heating apparatus which concerns on 5th Embodiment based on this invention. It is a figure explaining an Example. It is a figure explaining the heating rate in an Example. It is a figure which shows the shear crack generation condition in a shear plane. It is a figure which shows the temperature dependence of the hydrogen isotope diffusion coefficient in a body centered cubic metal. It is a figure which shows the relationship between a steel plate tensile strength and a hydrogen diffusion coefficient.

Next, embodiments of the present invention will be described with reference to the drawings.
“First Embodiment”
FIG. 1 is a schematic diagram showing an end face heating device 2 of this embodiment and its use.
The steel plate 1 heated in this embodiment is intended for the steel plate 1 cut online by a cutting device such as shear shear. The cut steel plate 1 is transported along the transport line L to the end surface heating position A, and is temporarily stopped at the end surface heating position A. And it heats with the end surface heating apparatus 2 of this embodiment installed in the said end surface heating position A in the state.

(Constitution)
The said end surface heating apparatus 2 is installed in the position which can oppose the end surface 1A which the steel plate 1 conveyed to the said end surface heating position A heats. The end surface heating device 2 includes an induction heating device, a moving mechanism, and an advance / retreat mechanism.

The structure of the said end surface heating apparatus 2 is demonstrated with reference to FIG.1 and FIG.2.
A traveling rail 3 is laid along the longitudinal direction of the cut surface of the steel plate 1 to be heated (the width direction of the steel plate 1). And the mobile body 4 of the end surface heating apparatus 2 is supported by the traveling rail 3 so that guidance is possible. That is, the moving body 4 is movable along the traveling rail 3. The moving body 4 can move along the traveling rail 3 by driving the driving device 5. Here, the driving device 5 may be configured by a cylinder device that moves the moving body 4 back and forth, or may be configured by a motor that drives a wheel (not shown) provided on the moving body 4. That is, the driving device 5 can employ a known driving device 5 as long as it can drive the moving body 4 guided by the traveling rail 3. Further, the guide of the moving body 4 need not be the traveling rail 3.

  A guide rail 6 extending in a direction intersecting with the traveling rail 3 is provided on the upper surface of the moving body 4. The intersection may be set, for example, in a direction orthogonal to the traveling rail 3, but does not need to be orthogonal. A support 7 is supported on the moving body 4 via the guide rail 6. The support body 7 is movable in a direction intersecting with the travel rail 3 while being guided by the guide rail 6, that is, is movable in a direction of moving back and forth with respect to the end surface 1 </ b> A of the target steel plate 1. A cylinder device 8 is connected to the support 7. The cylinder device 8 constitutes an advancing / retreating device that pushes and pulls the support body 7 in the extending direction of the guide rail 6 to move the support body 7 forward and backward with respect to the end surface 1A of the steel plate 1.

The driving device 5 and the cylinder device 8 are driven by a command from the controller 9.
Further, a heating coil 11 </ b> A that constitutes a heating unit of the induction heating device is fixed to the tip of the projecting body 10 that projects from the support 7 toward the end surface 1 </ b> A of the steel plate 1. The heating coil 11 </ b> A can heat the end surface 1 </ b> A of the steel plate 1 disposed in proximity by the alternating current supplied from the main body 11 of the induction heating device.

Here, the traveling rail 3 and the moving body 4 constitute a moving mechanism. The guide rail 6 and the support 7 constitute an advance / retreat mechanism.
At least one end surface heating device 2 having the above configuration is arranged in the longitudinal direction of the end surface 1A of the steel plate 1 that has been transported to the end surface heating position A (the width direction of the steel plate 1).

(Operation other)
The cylinder device 8 is driven with respect to the end surface 1A of the steel plate 1 that has been transported to the end surface heating position A, and the distance between the heating coil 11A and the end surface 1A of the steel plate 1 is set to a preset target proximity distance S. The support 7, that is, the heating coil 11 </ b> A is advanced with respect to the end surface 1 </ b> A of the steel plate 1.

  Here, the inventors use an induction heating method as a method for rapidly heating the end surface 1A of the steel plate 1, but the heating coil 11A for heating the end surface 1A is about 2 to 3 mm with respect to the end surface 1A. It is confirmed that it is necessary to place it in the proximity position. For this reason, the range of the target proximity distance S set in advance is set to be, for example, 2 mm or more and 3 mm or less. Then, the target proximity distance S is set to 2.5 mm, for example.

Here, the advancement / retraction of the heating coil 11A for setting the target proximity distance S is advanced / retracted by a predetermined advance / retreat amount when the steel plate 1 is assumed to be accurately stopped at the target position. That's fine. Or the stop position (position of end surface 1A) of the steel plate 1 is acquired with a sensor, and the advance / retreat amount is determined based on the detection of the sensor.
When the heating coil 11A comes close to the end surface 1A of the steel plate 1 to the target proximity distance S, the induction heating apparatus body 11 is driven to bring the heating coil 11A into the induction heating state, and then the moving body 4 is moved as shown in FIG. Movement along the rail, that is, the heating coil 11 </ b> A is moved along the end surface 1 </ b> A of the steel plate 1.

Thus, the end face 1A is heated while the heating coil 11A is translated along the longitudinal direction of the end face 1A of the steel sheet 1 while the distance between the end face 1A and the heating coil 11A is maintained at a constant value (= target proximity distance S). .
The target heating temperature may be obtained in advance by experiments or the like.
Then, the heating amount per unit time of the heating coil 11A and the moving speed of the heating coil 11A may be adjusted based on the target heating temperature.

  Here, the reason why only the cutting surface (end surface 1A) is locally rapidly heated is that, in the mechanical cutting of the thick steel plate 1, a portion that receives processing strain at the time of cutting is limited to the vicinity of the cutting surface. In the case of shearing, the part subjected to the processing strain is mainly the clearance setting region of the upper and lower blades at the time of cutting, and the region is hardened by work hardening, and a high tensile residual stress remains. Therefore, cracks may occur even with slight embrittlement factors such as transformation and hydrogen in steel. In the present embodiment, the heating is set so as to be performed up to a portion including the end surface 1A and the region.

  As described above, the end surface heating device 2 according to the present embodiment includes an advance / retreat mechanism for moving the heating coil 11A toward and away from the end surface 1A and a moving mechanism for moving the heating coil 11A parallel to the end surface 1A. It is a mechanism that can be driven. As a result, even if a non-smooth end surface 1A such as a sheared shear surface is to be heated, the end surface 1A is made uniform in the longitudinal direction of the end surface by moving it in a non-contact state with a constant distance between the end surface 1A and the heating coil 11A. It becomes possible to heat to.

At this time, as shown in FIG. 2, in the case where heating is simultaneously performed by a plurality of end face heating devices 2, the steel sheet 1 is also wide in a short time (the length in the longitudinal direction of the end face 1 </ b> A is long). It becomes possible to heat-process with.
The end surface heating device 2 of the present invention is particularly effective for heating the end surface 1A of the thick steel plate 1. Moreover, although described in the case where 1 A of end surfaces located in the longitudinal direction of the steel plate 1 are made into a heating object, 1 A of end surfaces located in the end surface of the steel plate 1 in the width direction may be made into heating objects. What is necessary is just to set the end surface 1A heated according to the cut surface.

“Second Embodiment”
Next, a second embodiment will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected and demonstrated about the structure similar to the said 1st Embodiment.
(Constitution)
The basic configuration of the end surface heating device 2 of the present embodiment is the same as that of the first embodiment.

However, the point which provided the pair of guide member 20 with respect to the support body 7 to which the said heating coil 11A is attached differs.
As shown in FIG. 3, the pair of guide members 20 are arranged with the heating coil 11 </ b> A in between in the moving direction of the moving body 4. Each guide member 20 is composed of a guide member 20 main body 20a that protrudes from the support 7 toward the end face 1A side of the steel plate 1 and a support roll 20b that is rotatably supported by the distal end portion of the guide member 20. The rotation axis of the support roll 20b faces the thickness direction of the steel plate 1 (vertical direction in the present embodiment). The support roll 20b constitutes a rolling part that rolls along the end face 1A.

  As shown in FIG. 3, the relative distance ΔX between the tangent line D in contact with the tip ends of the two support rolls 20b and the heating coil 11A is an appropriate distance between the end surface 1A of the steel plate 1 and the heating coil 11A (= target proximity distance). S), the positional relationship between the support roll 20b and the heating coil 11A is set in advance.

(Operation other)
In the said end surface heating apparatus 2, the support body 7 is moved toward the end surface 1A until the support roll 20b contact | abuts the end surface 1A of the steel plate 1, and the moving body 4 is moved along the end surface 1A in that state. That is, the support roll 20 b is moved in the longitudinal direction of the end surface 1 </ b> A by rolling it while being pressed against the end surface 1 </ b> A of the steel plate 1. Thus, even if the end surface 1A is a non-smooth surface, the pressed support roll 20b rolls, so that the interval between the end surface 1A and the heating coil 11A can be kept constant.

Further, by simply pressing the support roll 20b against the end surface 1A of the steel plate 1, the movement control of the support 7 is simplified, and the distance between the end surface 1A of the steel plate 1 and the heating coil 11A can be kept at a target proximity distance. It becomes possible.
Here, in the above description, the rolling part is described as being configured by the support roll 20b, but the rolling part is not limited to this. The rolling part may be a wheel or a ball that is rotatably supported. In short, it is only necessary to be able to roll along the end surface 1A of the pressed steel plate 1.

“Third Embodiment”
Next, a third embodiment will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected and demonstrated about the structure similar to the said 1st and 2nd embodiment.
(Constitution)
The basic configuration of the end surface heating device 2 of the present embodiment is the same as that of the second embodiment.

However, in the third embodiment, distance detection means for detecting the distance between the heating coil 11A and the end face 1A of the steel plate 1, protrusion amount changing means for changing the protrusion amount of each guide member 20 with respect to the support portion, and the above And a protrusion amount adjusting means for adjusting the protrusion amount of each guide member 20 via the protrusion amount changing means according to the distance detected by the distance detecting means.
That is, as shown in FIG. 4, a contact-type or non-contact-type displacement sensor 21 for detecting the distance between the end face 1A of the steel plate 1 and the heating coil 11A is provided in the heating coil 11A. This is an example of an apparatus configuration that makes it possible to keep the distance between the end surface 1A and the heating coil 11A within the range of the target proximity distance S even when the steel plate 1 is skewed.

  As shown in FIG. 5, when the steel plate 1 is inclined with respect to the conveyance line L and stopped, as shown in FIG. 6, the relative distance ΔX between the support roll 20 b and the heating coil 11 </ b> A shown in FIG. Only one of the support rolls 20b has a distance in contact with the end surface 1A of the steel plate 1. As a result, the relative distance ΔX between the end surface 1A of the steel plate 1 and the heating coil 11A is increased with respect to the target proximity distance S on average. And if the space | interval of the end surface 1A of the steel plate 1 and the heating coil 11A becomes large, it will become the cause of reducing the heating efficiency of induction heating.

  On the other hand, in this embodiment, as shown in FIG. 4, as the protrusion amount changing means, the guide member 20 main body 20a is a cylinder mechanism such as an air cylinder, and the length can be changed by a command from the controller 9. Make the configuration. A linear motion guide mechanism or the like may be employed instead of the cylinder mechanism as the protrusion amount changing means.

  The support 7 is provided with a displacement sensor 21 for detecting the distance to the end surface 1A of the steel plate 1 as a distance detecting means. The displacement sensor 21 may be a non-contact sensor such as a laser distance meter or a contact sensor. In the present embodiment, the pair of displacement sensors 21 are provided so as to be symmetrical with respect to the heating coil 11A. That is, the displacement sensor 21 is provided in the vicinity of each guide member 20 so as to correspond to each guide member 20. The displacement sensor 21 outputs a detection signal to the controller 9.

As shown in FIG. 4, the controller 9 includes guide adjustment means 9A.
As shown in FIG. 7, the guide adjusting means 9A first determines in step S100 whether or not the difference between the detection signals of the pair of displacement sensors 21 is less than a predetermined threshold value. Here, since the skew angle of the steel plate 1 is small, the predetermined threshold value of the difference between the detection signals of the pair of displacement sensors 21 is an inclination that falls within the range of the target proximity distance S even if the length of the guide member 20 is left in the initial state. The maximum value corresponding to the line angle.

When the difference between the detection signals of the pair of displacement sensors 21 is less than the predetermined threshold value, the length of each guide member 20 is left as the initial value. On the other hand, if it is determined that the difference between the detection signals of the pair of displacement sensors 21 is equal to or greater than the predetermined threshold, the steel plate 1 is determined to be in the skew state, and the process proceeds to step S110.
In step S110, first, an average value of the detection distances of the pair of displacement sensors 21 is taken. The average value is the average distance between the heating coil 11 </ b> A and the end face 1 </ b> A of the steel plate 1. Next, based on the deviation between the average value and the target proximity distance S, the length of the guide member 20 on the side close to the displacement sensor 21 where the detected distance is relatively small is calculated as the average value and the target proximity distance S. The amount of displacement for shortening the deviation so as to approach zero is calculated.

  Subsequently, in step S120, a displacement signal corresponding to the calculated displacement amount is output. Here, the support roll 20 b (the right side in FIG. 4) of the guide member 20 on the side close to the displacement sensor 21 whose detected distance is relatively small is in contact with the end surface 1 </ b> A of the steel plate 1.

  Here, the length of the guide member 20 (left side in FIG. 4) on the side close to the displacement sensor 21 having a relatively large detected distance is set to the length of the guide member 20 on the side close to the displacement sensor 21 having a relatively small detected distance. You may output the signal which lengthens only the part which changed (right side in FIG. 4) short. If this is not performed, there is a possibility that only one of the support rolls 20b (right side in FIG. 4) is in contact with the end face 1A of the steel plate 1. Since the moving direction of the support 7 moves only in a certain direction intersecting the moving rail, even in this state, the distance between the heating coil 11A and the end surface 1A of the steel plate 1 can be kept constant, but both supports When the roll 20b is brought into contact with the end surface 1A of the steel plate 1, the heating coil 11A can be moved stably while keeping the distance between the heating coil 11A and the end surface 1A of the steel plate 1 constant.

  The length adjustment of the guide member 20 by the controller 9 may be performed only once, or may be performed while moving the moving body 4 at a predetermined sampling period.

(Operation other)
As shown in FIG. 4, the amount of change in the distance between the end surface 1A of the steel plate 1 and the heating coil 11A is obtained from the skewness obtained from the relative displacement or absolute displacement based on the detection signal from the displacement sensor 21. Then, as shown by the arrows in FIG. 4, the skewed steel sheet is displaced by displacing the position of the support roll 20b (the right side in FIG. 4) that is in contact with at least the amount that cancels out this amount of change. It is possible to heat the end face 1A of the steel plate 1 with the distance between the end face 1A of 1 and the heating coil 11A maintained at the target proximity distance S or a value in the vicinity thereof, excluding the skew margin for the coil width. Become.

“Fourth Embodiment”
Next, a fourth embodiment will be described with reference to the drawings. In addition, about the structure similar to the said 1st-3rd embodiment, the same code | symbol is attached | subjected and demonstrated.
(Constitution)
The basic configuration of the end surface heating device 2 of the present embodiment is the same as that of each of the above embodiments.

However, as shown in FIG. 8, the difference is that a plate pressing device 23 is separately provided. The plate pressing device 23 is a device that restrains the displacement of the steel plate 1 that has been conveyed to a position where the heat treatment of the end face 1A is performed.
A plurality of the plate pressing devices 23 are arranged along the longitudinal direction of the end surface 1A to be heated above the vicinity of the end surface 1A to be heated in the steel plate 1 conveyed to the end surface heating position A as shown in FIG. Yes. FIG. 8 illustrates the case of three plate pressing devices 23. In the case of the thick steel plate 1 having high rigidity, three or more are preferable.

  Each plate pressing device 23 includes a pressing portion 23a that comes into contact with the upper surface of the steel plate 1 and a lifting device 23b that lifts and lowers the pressing portion. As the elevating device 23b, for example, a device that can restrain and pressurize the steel plate 1 and add a load that can be deformed is adopted by, for example, a cylinder device.

(Operation other)
With respect to the steel plate 1 conveyed to the end surface heating position A, the plate pressing device 23 is lowered, and the vicinity of the end surface 1A to be heated in the steel plate 1 is pressed against the lower conveying roller 30 side.

Thus, the displacement of the thick steel plate 1 is fixed by the plate pressing device 23.
Then, the end surface 1A of the steel plate 1 is heated as in the first to third embodiments.
By fixing the displacement of the thick steel plate 1 by the plate pressing device 23, it is possible to prevent the displacement of the steel plate 1 due to the pressing force when the support roll 20b is pressed against the end surface 1A of the steel plate 1, for example. Since the thick steel plate 1 is divided into various dimensions by shear shearing or the like, in the case of the steel plate 1 having a small width and length, in addition to the small mass of the steel plate 1 itself, the contact area with the transport roller 30 is also small. The position of the steel sheet 1 may be displaced by a relatively small force such as a pressing force from the support roll 20b. This displacement of the steel plate 1 can be prevented by the plate pressing device 23.

Further, depending on the shear angle at the time of shearing or the like, end warping as shown in FIG. 9 may occur on the shearing surface (end surface 1A), and vertical displacement may occur on the end surface 1A to be heated.
On the other hand, by increasing the pressing force by the plate pressing device 23, the end heating can be performed with the end warping corrected to the state shown in FIG. That is, even when the support roll 20b is not provided, the plate pressing device 23 is effective.

“Fifth Embodiment”
Next, a fifth embodiment will be described with reference to the drawings. In addition, about the structure similar to the said 1st-4th embodiment, the same code | symbol is attached | subjected and demonstrated.
(Constitution)
The basic configuration of the end surface heating device 2 of the present embodiment is the same as that of each of the above embodiments.
However, a retracting mechanism for retracting the heating coil 11A downward with respect to the transport line L is provided.

  The retracting mechanism will be described with reference to FIG. In addition, in FIG. 10, the case where the board press apparatus 23 demonstrated in 4th Embodiment is provided is illustrated. The plate pressing device 23 may be at a position facing the transport roller 30 in the vertical direction, or may be disposed above the position between the transport rollers 30.

In the present embodiment, one or a plurality of the transport rollers 30 at the end surface heating position A are removed, and a recess 25 for arranging the end surface heating device 2 having the above configuration is formed below the transport roller 30.
Further, the moving body 4 is divided into a lower member 4a and an upper member 4b, and an elevating device 4c such as a jack device is disposed between the lower member 4a and the upper member 4b.

  And in the state which shortened the said raising / lowering apparatus 4c, as shown in FIG. 10, it sets so that it may become a position which does not interfere with the steel plate 1 conveyed.

(Operation etc.)
As shown in FIG. 11, when the end surface 1 </ b> A heating is performed on the longitudinal end and the tail end of the thick steel plate 1, the heating is performed while moving in the direction crossing the transport line L of the thick steel plate 1. At this time, in the case of moving to the retreat position B as shown in FIG. 11 before and after heating, for example, after the end surface heating device 2 is once moved from the retreat position B to the heating start position (position shown in FIG. 11). The end face 1A is moved for heating and further moved to the retreat position B. For this reason, since it takes time to move the apparatus other than the movement for heating, the efficiency of the transport line L is inhibited accordingly.

In contrast, in the present embodiment, as shown in FIG. 10, the heating coil 11 </ b> A is moved in the vertical direction separately from the advance / retreat mechanism of the heating coil 11 </ b> A with respect to the end surface 1 </ b> A of the thick steel plate 1 and the moving mechanism for parallel movement. A retractable structure is provided.
For example, when heating the leading end surface 1A of the thick steel plate 1, as shown in FIG. 12, the thick steel plate 1 conveyed in the longitudinal direction on the conveying line L is placed at a predetermined position using a stopper (not shown). (Fig. 12 (a)), and the vertical displacement is restrained by using the plate pressing device 23. Subsequently, while simultaneously raising the heating coil 11A disposed below the conveying line L, the heating coil 11A is brought close to the end surface 1A of the thick steel plate 1 via the support roll 20b and heated while being fed in the width direction (FIG. 12B). ). Then, when the full width heating is completed, the heating coil 11A is retracted / lowered, and the conveyance of the thick steel plate 1 is immediately restarted (FIG. 12 (c)).

  As described above, when the retracting mechanism as shown in FIG. 12 is provided in the middle of the transport line L, the heating coil 11A is retracted downward when the end face 1A is not heated. Then, only when heating is performed, the heating coil 11A is moved upward to perform the heat treatment of the end face 1A. When the heat treatment is finished, it is possible to transport the steel plate 1 after the heat treatment by lowering the heat treatment, and after the descent, that is, while transporting the steel plate 1, the end surface heating device 2 is moved to the initial position. Can be put into a standby state. Thus, since the time required for apparatus movement other than the heating of the end face 1A is shortened, the end face 1A processing can be performed in a short time without impairing the efficiency of the transport line L.

  Here, in the said embodiment, the case where the heating coil 11A was evacuated below was illustrated. Instead of this, the heating coil 11A may be retracted upward. In this case, for example, the heating coil 11 </ b> A can be retracted to the upper side of the transport line L by suspending it on a portal frame that straddles the transport line L.

Examples of the present invention will be described below.
As shown in FIG. 13, the thermocouple 40 is attached to the end surface 1 </ b> A of the steel plate 1 with a plate thickness of 38 mm and a plate width of 1800 mm, as shown in FIG. 13, and then induction heating with an output of 200 kW-10 kHz is performed. Using the apparatus, the end face 1A was heated under the conditions of an interval between the end face 1A and the heating coil 11A of 2.5 mm and a width feed rate of 100 mm / sec.

FIG. 14 shows the temperature history measurement result at that time. When heating, two support rolls 20b were provided near the heating coil 11A, and heating was performed while pressing the support roll 20b against the end face 1A with an air cylinder.
From the result shown in FIG. 14, it can be seen that in this case, the end face 1 </ b> A temperature of the end face 1 </ b> A of the steel plate 1 is rapidly heated at a heating rate of 700 ° C. or higher when heated for 2 seconds. Accordingly, for example, when the same end surface 1A heating is performed in 10 seconds for the end surface 1A of the thick steel plate 1 having a width of 3000 mm, three induction heating devices are provided at intervals of 1000 mm in the width direction, and the same width feed is performed. It can be seen that heating at a speed of 100 mm / sec may be performed.

DESCRIPTION OF SYMBOLS 1 Steel plate 1A End surface 2 End surface heating device 3 Traveling rail 4 Moving body 4a Lower member 4b Upper member 4c Lifting device 5 Drive device 6 Guide rail 7 Support body 8 Cylinder device 9 Controller 9A Guide adjusting means 11A Heating coil 20 Guide member 20b Support Roll (rolling part)
21 Displacement sensor (distance detection means)
23 Plate holding device 25 Recess 30 Conveying roller A End surface heating position B Retraction position D Tangent L Conveying line S Target proximity distance ΔX Relative distance

Claims (6)

An end surface heating device for heating an end surface of a cut steel sheet,
A heating part of an induction heating device disposed opposite to the end face to be heated;
An advancing and retreating mechanism for advancing and retreating the heating unit disposed opposite to the end surface with respect to the end surface;
Adjusting means for adjusting the position of the heating part relative to the end face so that the distance between the heating part advanced by the advance / retreat mechanism and the steel plate end face falls within a preset target proximity distance range ;
Moving the distance of the end surface and by the adjustment means adjustable state as within the range of the target close distance, a heating unit which is disposed opposite to the end surface, in one direction which is set in advance along the end face A moving mechanism
Equipped with a,
An apparatus for heating an end face of a steel sheet, wherein the length of the heating section is shorter than the length of the end face of the steel sheet in a direction along the moving direction of the heating section by the moving mechanism . In the moving direction of the heating unit by the moving mechanism, a pair of guide members arranged with the heating unit interposed therebetween,
The advancing / retreating mechanism allows the heating unit to advance and retreat by advancing and retracting the support unit that supports the heating unit,
Each guide member have a rolling portion toward the end face of the steel plate from the support portion protrudes, the front end portion close to the end face than the heating section,
The apparatus for heating an end face of a steel sheet according to claim 1, further comprising a protrusion amount changing means for changing a protrusion amount of each guide member with respect to the support portion as the adjusting means . The adjusting means further includes a distance detecting means for detecting a distance between the heating unit and the end face ;
E Bei a protrusion amount adjustment means for the distance detection means to adjust the amount of protrusion of the guide member through the protrusion amount changing means in a direction within the range of the target proximity distance distance detected is set in advance, and
The distance detection means includes a pair of displacement sensors arranged with the heating unit sandwiched in the moving direction of the heating unit by the moving mechanism, and based on detection values of the pair of displacement sensors, the heating unit and the end surface The apparatus for heating an end face of a steel sheet according to claim 2, wherein the distance is detected .   The steel plate end surface heating device according to any one of claims 1 to 3, further comprising a plate pressing device that restrains the displacement of the steel plate that has been transported to a position where the heat treatment of the end surface is performed. The heating unit is arranged in the middle of the conveyance line for conveying the steel plate,
The steel sheet end surface heating device according to any one of claims 1 to 4, further comprising a retraction mechanism for retreating the heating unit upward or downward with respect to the conveyance line. The cut steel sheet, on the way in a state of temporarily stopping the conveying line of the steel sheet, the heating portion of the induction heating device, is brought close to the steel plate end face, the target proximity distance distance between the steel plate end face preset In a state in which the position of the heating part can be adjusted so as to be within the range, the steel plate end face is induction-heated by parallel movement toward the preset one direction along the end face, and the moving direction of the heating part The length of the said heating part is shorter than the length of the end surface of the said steel plate, The end surface heating apparatus of the steel plate characterized by the above-mentioned .

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