Slab extraction control method and slab extraction apparatus

Abstract

To provide a technique which, upon extracting slabs from a continuous heating furnace, prevents the slabs from slipping down during extractor retreat.SOLUTION: A slab extraction control method in a continuous heating furnace in which slabs in the continuous heating furnace are extracted by an extractor comprises the steps of: executing, in a control unit, classification at least by the steel type of the slabs and setting an acceleration speed at the start of the horizontal retreat of the extractor for each classification category; selecting, in the control unit, an acceleration speed for a classification category equivalent to each slab to be extracted from the acceleration speeds at the start of the horizontal retreat for respective classification categories and transmitting the acceleration information to a drive device of the extractor; and controlling the drive device based on control information including the transmitted acceleration information and extracting each slab from the inside of the continuous heating furnace by the extractor.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a slab extraction control method and a slab extraction device for extracting a slab in a continuous heating furnace. [Background technology]

[0002] When extracting slabs from a continuous heating furnace (hereafter simply referred to as heating furnace) in a hot rolling mill, an extractor, which consists of two forks on the east and west sides, is advanced to load the slab into the heating furnace, then the extractor is raised to lift the slab, and then retracted to extract the slab from the heating furnace. During this process, the slab may slip and fall, or it may snake around inside the heating furnace and be lost from the grasp, causing it to fall.

[0003] As a technology for preventing slabs from falling, Patent Document 1 proposes that two types of sensors installed inside the heating furnace monitor the distance the slab moves inside the heating furnace and the distance the extractor moves, and by comparing these, it is possible to predict welding with subsequent material or the extracted material moving inclinedly, thereby preventing the slab from falling when extracted. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-223463 Summary of the Invention [Problem to be solved by the invention]

[0005] In reality, when extracting a slab, the slab often slips and falls when the extractor starts to retreat and accelerates to a steady (constant) speed. In particular, with high-tensile steel (hereinafter referred to as "high-tensile steel"), which is a high-strength steel with a tensile strength of 590 to 1470 MPa, an oxide film called scale often forms on the surface of the slab. This reduces the coefficient of friction between the extractor and the slab, increasing the likelihood of the slab falling.

[0006] However, the technology described in Patent Document 1 above is intended to prevent the slab from falling during extraction due to welding with subsequent material or the extracted material moving obliquely, but it cannot prevent the slab from sliding off when the extractor is retracted.

[0007] The present invention provides a technique for preventing a slab from slipping off when an extractor is retracted when extracting the slab from a continuous heating furnace. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides the following means [1] to

[10] .

[0009] [1] A method for controlling slab extraction in a continuous heating furnace, in which slabs in the continuous heating furnace are extracted by an extractor, comprising: The control unit is configured to classify the slab according to at least the steel type, and set an acceleration at the start of horizontal retreat of the extractor according to each classification; In the control unit, from the acceleration at the start of the horizontal retreat for each section, select the acceleration of the section corresponding to the slab to be extracted, and transmit the acceleration information to the drive device of the extractor; Controlling the drive device based on the transmitted control information including the acceleration information to extract the slab from the continuous heating furnace by the extractor; A slab extraction control method comprising:

[0010] [2] The slab extraction control method according to [1], wherein the classification is performed based on the steel type, thickness, and width of the slab.

[0011] [3] A slab extraction control method according to [1], in which, when the steel type is a specific steel type that is prone to slab sliding, the acceleration at the start of the horizontal retreat is set to be lower than that of other steel types.

[0012] [4] A slab extraction control method according to [3], in which, when the steel type is a specific steel type that is prone to slab sliding, the acceleration at the start of the horizontal retreat is set to be 30 to 40% lower than that of other steel types.

[0013] [5] A slab extraction control method according to claim 3 or claim 4, wherein the specific steel type is high-tensile steel.

[0014] [6] A method for controlling extraction of slabs in a continuous heating furnace, in which slabs in the continuous heating furnace are extracted by an extractor, comprising: The control unit classifies the slabs at least by steel type, sets the acceleration at the start of horizontal retreat of the extractor according to each classification, and allows the operator to set the acceleration at the start of horizontal retreat of the extractor; In the control unit, from the acceleration at the start of horizontal retreat for each section, select the acceleration of the section corresponding to the slab to be extracted, or select the acceleration at the start of horizontal retreat set by the operator, and transmit the selected acceleration information to the drive device of the extractor; The drive device controls the extractor to extract the slab from the continuous heating furnace based on the control information including the acceleration information transmitted. A slab extraction control method comprising:

[0015] [7] A slab extractor for extracting slabs in a continuous heating furnace, an extractor having a support member and a fork portion supported by the support member, the fork portion performing a horizontal retreating movement to extract the slab from the continuous heating furnace; a drive device that drives the extractor; a control unit that controls the drive device and controls the operation of the extractor; and The control unit Classifying the slab at least according to the steel type, and setting the acceleration at the start of horizontal retreat of the extractor according to each classification; selecting an acceleration of a section corresponding to the slab to be extracted from the acceleration at the start of the horizontal retreat for each section, and transmitting the selected acceleration information to the drive device; Controlling the drive device based on the transmitted control information including the acceleration information to extract the slab from the continuous heating furnace by the extractor; A slab extractor that performs the above.

[0016] [8] The control unit sets the acceleration at the start of horizontal retreat to be lower than that of other steel types when the steel type is a specific steel type that is prone to slab sliding. [7] A slab extraction device as described in [7].

[0017] [9] The slab extraction control method described in [8], wherein the control unit sets the acceleration at the start of horizontal retreat to be 30 to 40% lower than that for other steel types when the steel type is a specific steel type that is prone to slab sliding.

[0018]

[10] A slab extractor for extracting slabs in a continuous heating furnace, an extractor having a support member and a fork portion supported by the support member, the fork portion performing a horizontal retreating movement to extract the slab from the continuous heating furnace; a drive device that drives the extractor; a control unit that controls the drive device and controls the operation of the extractor; A selection means for an operator to select whether the acceleration at the start of horizontal retreat of the extractor is set by the control unit or manually by the operator; and When the selection means selects that the acceleration at the start of horizontal retreat is to be set by the control unit, the control unit classifies the slab at least by the steel type, sets the acceleration at the start of horizontal retreat of the extractor according to each classification, selects the acceleration of the classification corresponding to the slab to be extracted from the acceleration at the start of horizontal retreat for each classification, and transmits the selected acceleration information to the drive device. When the selection means selects that the acceleration at the start of horizontal reverse be set manually by the operator, the control unit transmits the acceleration information manually set by the operator to the drive device, A slab extractor that controls the drive device based on control information including the transmitted acceleration information to cause the extractor to extract the slab from within the continuous heating furnace. [Effects of the Invention]

[0019] According to the present invention, a technique is provided for preventing a slab from slipping off when an extractor is retracted when extracting the slab from a continuous heating furnace. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic diagram showing a slab extraction facility for carrying out a slab extraction control method according to an embodiment of the present invention. FIG. [Figure 2] FIG. [Figure 3] FIG. 10 is a diagram showing an operation screen of a cab operation terminal. [Figure 4] 1 is a flowchart showing an example of a slab extraction control method using slab extraction equipment. [Figure 5] 10 is a flowchart showing another example of a slab extraction control method using slab extraction equipment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0022] FIG. 1 is a schematic diagram showing a slab extraction facility for carrying out a slab extraction control method according to an embodiment of the present invention, and FIG. 2 is an oblique view showing an extractor.

[0023] As shown in Figure 1, the slab extraction equipment 100 extracts a slab 2 from a heating furnace 1 through an extraction port 1a and transports it to an extraction table 6, and is equipped with an extractor 3, a motor 4, a drive device (motor drive device) 5, a control unit 10, and a cab operation terminal 13.

[0024] As shown in Figure 2, the extractor 3 has a support member 31 and a fork portion 32 supported by the support member 31. The extractor 3 is connected to a motor 4, and the extractor 3 can be operated by driving the motor 4 with a drive device (motor drive device) 5. When extracting a slab, the extractor 3 rises from the extractor standby position after the extraction door of the heating furnace 1 opens, moves forward horizontally, and is loaded into the heating furnace. The extractor 3 then rises, lifts the slab 2 with the fork portion 32, and moves backward horizontally to extract the slab 2 from the heating furnace 1. After extracting the slab, the extractor 3 descends, places the slab 2 on the extraction table 6, and returns to the standby position, completing the series of operations.

[0025] The control unit 10 includes a P / C (process computer) 11 and a PLC (programmable controller) 12, and controls the operation of the extractor 3, particularly the acceleration control at the start of horizontal backward movement.

[0026] P / C11 is a higher-level controller that classifies slabs 2 at least by steel type, and sets the acceleration at the start of horizontal retreat when extracting the slab by the extractor 3 for each classification. PLC12 is a lower-level controller that selects the value of the classification that corresponds to the slab to be extracted from the acceleration at the start of horizontal retreat for each classification of P / C11, and transmits the acceleration information to the drive unit 5. Slabs 2 may be classified at least by the steel type of the slab, but it is preferable to classify them by the steel type, thickness, and width of the slab.

[0027] In this way, by appropriately setting the acceleration at the start of horizontal retraction of the extractor 3 in the P / C 11 for each category, it is possible to effectively prevent the slab 2 from sliding during extraction. In particular, by setting the acceleration at the start of horizontal retraction lower for specific steel grades prone to slab 2 sliding, such as high-tensile steel, which is prone to scaling and slippery, than for other steel grades, the slab 2 of such specific steel grades can be prevented from sliding. In this case, it is preferable to set the acceleration at the start of horizontal retraction of the extractor 3 for such specific steel grades 30 to 40% lower than for other steel grades. While the acceleration at the start of horizontal retraction of the extractor 3 is usually a fixed value, reducing the acceleration by 30 to 40% for only the relevant steel grades can prevent the slab from falling. Setting the acceleration at the normal value can lead to the slab falling, while reducing the acceleration too much can lead to a decrease in efficiency. Therefore, a range of 30 to 40% is set as the preferred range.

[0028] The cab operation terminal 13 is operated by the operator and has an operation screen. The acceleration when the extractor 3 is reversing is basically set by the P / C 11 as described above, but the operator can also set it on the cab operation terminal 13.

[0029] FIG. 3 is a diagram showing the operation screen 20. As shown in this figure, the operation screen 20 corresponds to multiple heating furnaces and includes a display screen 21 that displays the furnace status, and an operation unit 22. The operation unit 22 is a touch panel, and for each heating furnace, there is a P / C icon 23 and an HMI icon 24. Touching the P / C icon 23 switches to a mode in which the acceleration set in the P / C 11 is used as the acceleration at the start of retraction of the extractor 3, and touching the HMI icon 24 switches to a mode in which the operator can arbitrarily set the acceleration. The operation unit 22 also displays the set acceleration and actual speed when the HMI icon 24 is touched, as well as the set acceleration when the P / C icon 23 is touched.

[0030] Next, an example of a slab extraction control method using the slab extraction equipment 100 configured as described above will be described. FIG. 4 is a flowchart showing an example of a slab extraction control method according to an embodiment of the present invention.

[0031] First, the P / C 11 classifies the slab 2 at least by steel type, and sets the acceleration at which the extractor 3 starts to move back horizontally for each classification (STEP 1). Appropriate values ​​for this acceleration are determined and set in advance for each classification. The slab 2 may be classified at least by the steel type of the slab, but it is preferable to classify the slab by the steel type, thickness, and width.

[0032] The acceleration at the start of horizontal retreat set in this embodiment is the acceleration in the region where the horizontal retreat operation starts and the retreat speed is accelerated to a steady speed (a constant value regardless of the material) when extracting the slab 2 from the heating furnace 1. Conventionally, this acceleration has been a fixed value, but in this embodiment, this acceleration is variable and can be set appropriately for each section. This allows the acceleration to be set so that the slab 2 does not slide, effectively preventing the slab 2 from sliding. In particular, for certain steel types that are prone to slab 2 slide-off, such as high-tensile steel that is prone to scaling and slide-off, setting the acceleration at the start of horizontal retreat lower than for other steel types can prevent the slab 2 from sliding off. However, as mentioned above, lowering the acceleration at the start of horizontal retreat too much can lead to a decrease in efficiency. Therefore, it is preferable to set the acceleration at the start of retreat of the extractor 3 3 to be 30 to 40% lower than the steady-state acceleration.

[0033] In P / C11, the steel type is identified as a character code consisting of several characters, and for certain steel types that are prone to slipping, such as high-tensile steel, it is preferable to control the acceleration of the extractor 3 at the start of horizontal retreat to be uniquely reduced to a predetermined value regardless of thickness or width.

[0034] Next, the PLC 12 selects the acceleration of the section corresponding to the extracted slab from the acceleration at the start of horizontal retreat for each section of the P / C 11, and transmits the acceleration information to the drive device 5 (STEP 2).

[0035] Next, the drive device 5 is controlled based on the control information including the acceleration information transmitted from the PLC 12, and the motor 4 is driven to extract the slab 2 from the heating furnace 1 by the extractor 3 (STEP 3). To extract the slab 2, the extraction door (not shown) of the heating furnace 1 is opened, the extractor 3 is moved from the standby position to the extraction position, and is then moved forward to load the slab 2 into the heating furnace 1 through the extraction port 1a, and the fork portion 32 of the extractor 3 is moved to a position corresponding to the underside of the slab 2. The extractor 3 is then raised to place the slab 2 on the fork portion 32, and the extractor 3 is then moved backward at a set acceleration to move it above the extraction table 6, and the extractor 3 is then lowered to place the slab 2 on the extraction table 6.

[0036] As described above, in this example, the steel is divided into categories at least by type, and the acceleration at the start of horizontal retraction of the extractor 3 is set according to each category. From the acceleration at the start of horizontal retraction for each category, the acceleration for the category corresponding to the slab to be extracted is selected, and the acceleration information is transmitted to the drive device 5 to control the extraction of the slab 2. This makes it possible to appropriately set the acceleration at the start of horizontal retraction, effectively preventing the slab from sliding during extraction. In particular, when the steel is a specific type that is prone to slab 2 sliding, such as high-tensile steel that generates a lot of scale, the acceleration at the start of horizontal retraction of the extractor 3 can be made lower than for other steel types to prevent the slab 2 from sliding.

[0037] Next, another example of a slab extraction control method using the slab extraction equipment 100 configured as described above will be described. FIG. 5 is a flowchart showing another example of the slab extraction control method according to the embodiment of the present invention.

[0038] First, the P / C 11 classifies the slab 2 at least by steel type, sets the acceleration at which the extractor 3 starts to retreat horizontally according to each classification, and allows the operator to arbitrarily set the acceleration at which the extractor 3 starts to retreat horizontally (STEP 11).

[0039] That is, the acceleration when the extractor 3 starts to move backward horizontally is basically set by the P / C 11 as described above, but it can also be set by the operator on the operation screen 20 of the cab operation terminal 13. This is because there are cases where it is desired to lower the acceleration of the extractor 3 uniformly or regardless of the material, such as when an operational problem causes the slab 2 to meander inside the furnace, which could result in the slab 2 not being grasped, or when the slab 2 remains in the furnace for a long time, causing noticeable scaling of the slab 2.

[0040] Next, the PLC 12 selects either the acceleration of the section corresponding to the slab extracted from the acceleration at the start of horizontal retreat for each section of the P / C 11, or the acceleration at the start of horizontal retreat set by the operator, and transmits the selected acceleration information to the drive unit 5 (STEP 12).

[0041] Next, the drive device 5 is controlled based on the control information including the acceleration information transmitted from the PLC 12, and the motor 4 is driven to extract the slab 2 from the heating furnace 1 by the extractor 3 (STEP 13).

[0042] As described above, in this example, the system is divided into categories based on at least the steel type, and the acceleration at the start of horizontal retraction of the extractor 3 is set according to each category. Furthermore, the operator can arbitrarily set the acceleration at the start of horizontal retraction of the extractor 3. Then, the acceleration for the category corresponding to the slab to be extracted is selected from the acceleration at the start of horizontal retraction for each category, or the acceleration at the start of horizontal retraction set by the operator is selected, and extraction control of the slab 2 is performed based on control information including the selected acceleration information. By selecting the P / C setting mode, the acceleration at the start of horizontal retraction of the extractor 3 can be appropriately set for each category, effectively preventing the slab 2 from sliding down during extraction. Furthermore, by selecting the operator setting mode, operational problems can also be dealt with.

[0043] <Other applications> Although the embodiments of the present invention have been described above, these are merely examples and should not be considered limiting. The above embodiments may be omitted, substituted, or modified in various ways without departing from the spirit of the present invention.

[0044] For example, the slabs 2 are classified at least by the steel type, for example, the steel type, thickness, and width of the slab, but this is not limitative, and for example, weight may also be added.

[0045] Furthermore, although the control unit has a P / C and a PLC, the control unit may be an integrated unit that is not separated into a P / C and a PLC. [Explanation of symbols]

[0046] 1. Continuous heating furnace 1a Extraction port 2. Slab 3 Extractor 4 motors 5 Drive device 6 Extraction Table 10 Control Unit 11 P / C 12 PLC 13 Driver's cab control terminal 20 Operation screen 21 Display screen 22 Control section 23 P / C Icon 24 HMI Icons 31 Support part 32 Fork section

Claims

1. A method for controlling extraction of slabs in a continuous heating furnace, in which slabs in the continuous heating furnace are extracted by an extractor, comprising: The control unit is configured to classify the slab according to at least the steel type, and set an acceleration at the start of horizontal retreat of the extractor according to each classification; In the control unit, from the acceleration at the start of the horizontal retreat for each section, select the acceleration of the section corresponding to the slab to be extracted, and transmit the acceleration information to the drive device of the extractor; Controlling the drive device based on the transmitted control information including the acceleration information to extract the slab from the continuous heating furnace by the extractor; A slab extraction control method comprising:

2. The slab extraction control method according to claim 1, wherein the classification is performed based on the steel type, thickness, and width of the slab.

3. 2. The slab extraction control method according to claim 1, wherein when the steel type is a specific steel type that is prone to slab sliding, the acceleration at the start of the horizontal retreat is set to be lower than that for other steel types.

4. The slab extraction control method according to claim 3, wherein when the steel type is a specific steel type that is prone to slab sliding, the acceleration at the start of the horizontal retreat is set to be 30 to 40% lower than that of other steel types.

5. The slab extraction control method according to claim 3 or 4, wherein the specific steel type is a high-tensile steel.

6. A method for controlling extraction of slabs in a continuous heating furnace, in which slabs in the continuous heating furnace are extracted by an extractor, comprising: The control unit classifies the slabs at least by steel type, sets the acceleration at the start of horizontal retreat of the extractor according to each classification, and allows the operator to set the acceleration at the start of horizontal retreat of the extractor; In the control unit, from the acceleration at the start of horizontal retreat for each section, select the acceleration of the section corresponding to the slab to be extracted, or select the acceleration at the start of horizontal retreat set by the operator, and transmit the selected acceleration information to the drive device of the extractor; The drive device controls the extractor to extract the slab from the continuous heating furnace based on the control information including the acceleration information transmitted. A slab extraction control method comprising:

7. A slab extraction device for extracting slabs in a continuous heating furnace, an extractor having a support member and a fork portion supported by the support member, the fork portion performing a horizontal retreating movement to extract the slab from the continuous heating furnace; a drive device that drives the extractor; a control unit that controls the drive device and controls the operation of the extractor; and The control unit Classifying the slab at least according to the steel type, and setting the acceleration at the start of horizontal retreat of the extractor according to each classification; selecting an acceleration of a section corresponding to the slab to be extracted from the acceleration at the start of the horizontal retreat for each section, and transmitting the selected acceleration information to the drive device; Controlling the drive device based on the transmitted control information including the acceleration information to extract the slab from the continuous heating furnace by the extractor; A slab extractor that performs the above.

8. The slab extraction device according to claim 7, wherein the control unit sets the acceleration at the start of the horizontal retreat to be lower than that of other steel types when the steel type is a specific steel type that is prone to slab sliding.

9. The slab extraction device according to claim 8, wherein the control unit sets the acceleration at the start of the horizontal retreat to be 30 to 40% lower than that of other steel types when the steel type is a specific steel type that is prone to slab sliding.

10. A slab extraction device for extracting slabs in a continuous heating furnace, an extractor having a support member and a fork portion supported by the support member, the fork portion performing a horizontal retreating movement to extract the slab from the continuous heating furnace; a drive device that drives the extractor; a control unit that controls the drive device and controls the operation of the extractor; A selection means for an operator to select whether the acceleration at the start of horizontal retreat of the extractor is set by the control unit or manually by the operator; and When the selection means selects that the acceleration at the start of horizontal retreat is to be set by the control unit, the control unit classifies the slab at least by the steel type, sets the acceleration at the start of horizontal retreat of the extractor according to each classification, selects the acceleration of the classification corresponding to the slab to be extracted from the acceleration at the start of horizontal retreat for each classification, and transmits the selected acceleration information to the drive device. When the selection means selects that the acceleration at the start of horizontal reverse be set manually by the operator, the control unit transmits the acceleration information manually set by the operator to the drive device, A slab extractor that controls the drive device based on control information including the transmitted acceleration information to cause the extractor to extract the slab from within the continuous heating furnace.

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