A method for detecting warping of rough-rolled slab

Abstract

This invention provides a method for detecting slab head tilting in rough rolling, comprising the following steps: acquiring real-time slab height information of the slab under test by setting up multiple slab height detection devices, and feeding the slab height information back to a PLC processing unit; calculating the actual height of the slab head tilting based on the acquired slab height information and a preset slab width value; recording the real-time height of the slab under test through a preset PLC program, and filtering out the maximum value of the real-time height by comparing it every two scanning cycles through the PLC program; displaying the maximum height on a display device; calculating the absolute height Δh of the head tilting based on the actual slab thickness; determining whether the absolute height has reached a preset height through a preset PLC program; if it has reached the preset height, stopping the operation; otherwise, continuing rolling normally. This method can effectively reduce losses caused by slab head tilting, improve overall work efficiency, and reduce economic losses.

Description

Technical Field

[0001] This invention relates to the technical field of automatic steel inspection, and more particularly to a method for detecting the warping of rough-rolled slabs. Background Technology

[0002] In the 1580 hot-rolling production line, the roughing mill controls the thickness and width of the slab to roll it into an intermediate slab that meets process requirements before being sent to the next process. During the rolling process, factors such as the elevation of the lower work roll, slight differences in roll diameter causing speed deviations, and slab slippage on the rolls can cause the slab head to tilt upwards or downwards significantly, a condition known as "head knocking." Head knocking has a significant impact on the equipment. If the head knocking is too high, the slab head cannot enter the mill for rolling, causing steel to pile up due to obstruction, resulting in damage to the vertical rolls and guide equipment. If the head knocking is too low, it causes mechanical impact on the roller table during slab handling, affecting the surface quality of the roller table, loosening bearing housing bolts, loosening motor bases, and causing motor burnout due to vibration. Therefore, the desired control is for the slab to be rolled with a slight head knocking, reducing the impact on the equipment during handling while ensuring smooth entry into the mill for rolling. Previously, the judgment of slab warping was entirely based on visual assessment of the degree of warping at the slab head by production operators. Because everyone's standards differed, the judged degree of warping also varied, which could not meet the actual needs on site. Therefore, an automated detection system is needed to monitor the degree of warping in slabs in real time, ultimately achieving the goal of controlling warping. Summary of the Invention

[0003] The invention addresses the technical problem of the lack of a unified standard for judging the degree of warping in rough-rolled slabs, which fails to meet actual field requirements. Therefore, it provides a method for detecting warping in rough-rolled slabs. This invention primarily utilizes a method for detecting warping in rough-rolled slabs. A PLC is used to acquire relevant data during the movement of the rough-rolled slab in real time, enabling the detection system to automatically detect the degree of warping in the slab in real time, thereby controlling the warping.

[0004] The technical means employed in this invention are as follows:

[0005] A method for detecting warping of rough-rolled slabs includes the following steps:

[0006] Step 1: By setting up multiple slab height detection devices, the real-time slab height information of the slab to be tested is obtained, and the slab height information is fed back to the PLC processing unit;

[0007] Step 2: Calculate the actual height of the slab's upturned end based on the obtained slab height information and the preset slab width value;

[0008] The actual height of the upturned end of the slab is: H=tan[a*(L2-1 / 2L1)];

[0009] Wherein, H represents the total height of the slab warping; a represents the detection angle of the slab height detection device; L1 represents the actual width of the intermediate slab in the rough rolling mill; and L2 represents the distance between the slab height detection device and the center line of the conveyor rollers.

[0010] Step 3: Record the real-time height of the slab under test using a preset PLC program, and filter out the maximum value of the real-time height by comparing it every two scanning cycles using the PLC program; then display the maximum height on the display device.

[0011] Step 4: Calculate the absolute height Δh of the warp head based on the actual slab thickness;

[0012] Step 5: Determine whether the absolute height has reached the preset height through the preset PLC program. If it has reached the preset height, proceed to step 6; otherwise, proceed to step 7.

[0013] Step 6: The slab swings in front of the second mill stand in the roughing rolling area, that is, the slab moves back and forth in front of the mill without entering the mill for rolling, waiting for the instruction to return it to the furnace;

[0014] Step 7: If the warpage height of the slab to be tested is normal and no alarm message is issued, proceed with normal rolling.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] The detection method proposed in this application can effectively save time and generate benefits from accidents: assuming 2 accidents occur per year, each accident requires 6 hours to handle, the accident rate is 0.7, the current hourly output is 500 tons / hour, and the profit per ton of steel is 372.23 yuan, then the annual benefit is 2*6*500*372.23*0.7 = 1,563,300 yuan / year.

[0017] Meanwhile, the benefits of saving spare parts costs through the method of this application are as follows: the cost of the guide hydraulic cylinder and the guide is about 63,000 yuan, so the cost saving is 2 * 63,000 = 126,000 yuan / year; the method of this invention can improve work efficiency by more than 30% by calculating the accident time; the cumulative benefit is: 1,563,300 + 126,000 = 1,689,300 yuan / year. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the detection method apparatus of the present invention.

[0020] Figure 2 This is a schematic diagram of the overall process of the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] like Figure 1-2 As shown, the present invention provides a method for detecting warping of rough-rolled slabs, comprising the following steps:

[0024] Step 1: By setting up multiple slab height detection devices, the real-time slab height information of the slab to be tested is obtained, and the slab height information is fed back to the PLC processing unit; as a preferred embodiment, in this application, multiple detection devices can be set up, specifically, they need to be able to obtain the real-time height data of the slab to be tested during its movement.

[0025] Step 2: Based on the obtained slab height information and the preset slab width value (in a preferred embodiment, the length L varies with the slab width during actual production), calculate the actual height of the slab head; the actual height of the slab head is: H = tan[a*(L2-1 / 2L1)]; where H represents the total height of the slab head; a represents the detection angle of the slab height detection device; L1 represents the actual width of the intermediate slab in the rough rolling mill; L2 represents the distance between the slab height detection device and the center line of the conveyor rollers.

[0026] Step 3: The real-time height of the slab under test is recorded using a preset PLC program. The maximum real-time height is selected by comparing the values ​​every two scan cycles using the PLC program. The maximum height is then displayed on the display device. In Step 3, the 4-20mA signal output by the slab height detection device is transmitted to the preset PLC program. The real-time slab height information is calculated based on the output 4-20mA signal. When the detected height is greater than a preset value, the detection length of the slab is calculated by integrating the roller speed. When the detection length is greater than a preset value, the height selection process stops.

[0027] Step 4: Calculate the absolute height Δh of the warped head based on the actual slab thickness; in Step 4, the absolute height Δh is:

[0028] Δh = Hh;

[0029] Where Δh represents the absolute height of the slab's upward tilt; h represents the thickness of the intermediate slab during rough rolling; and H represents the total height of the slab's upward tilt. The roll gap between the two work rolls is recorded during slab rolling; this roll gap represents the actual thickness of the slab.

[0030] In one preferred embodiment, the absolute height Δh is set to 280mm-450mm in this application. This can be understood as meaning that in other embodiments, the specific absolute height can be set according to actual production needs, as long as it allows the slab to achieve normal rolling.

[0031] Step 5: Determine whether the absolute height has reached the preset height through the preset PLC program. If it has reached the preset height, proceed to step 6; otherwise, proceed to step 7.

[0032] Step 6: The slab swings in front of the second mill stand in the roughing rolling area, that is, the slab moves forward for a period of time in front of the mill, and then moves backward for a period of time, without entering the mill for rolling, waiting for the return to the furnace command; in Step 6, when it does not enter the mill for rolling, an alarm is triggered by the alarm unit. The user confirms the actual warping height of the slab. If the detection matches the actual height, the slab cannot be rolled and needs to be returned to the slab warehouse.

[0033] Step 7: If the warpage height of the slab to be tested is normal and no alarm message is issued, proceed with normal rolling.

[0034] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0035] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting warping of rough-rolled slabs, characterized in that, Includes the following steps: Step 1: By setting up multiple slab height detection devices, the real-time slab height information of the slab to be tested is obtained, and the slab height information is fed back to the PLC processing unit; Step 2: Calculate the actual height of the slab's upturned end based on the obtained slab height information and the preset slab width value; The actual height of the upturned end of the slab is: H=tan[a * (L2-1 / 2L1)]; Wherein, H represents the total height of the slab warping; a represents the detection angle of the slab height detection device; L1 represents the actual width of the intermediate slab in the rough rolling mill; and L2 represents the distance between the slab height detection device and the center line of the conveyor rollers. Step 3: Record the real-time height of the slab under test using a preset PLC program, and filter out the maximum value of the real-time height by comparing it every two scanning cycles using the PLC program; then display the maximum height on the display device. Step 4: Calculate the absolute height Δh of the warped head based on the actual slab thickness; in Step 4, the absolute height Δh is: Δh = Hh; Where Δh represents the absolute height of the slab upturn; h represents the thickness of the intermediate slab in the rough rolling process; and H represents the total height of the slab upturn. Step 5: Determine whether the absolute height has reached the preset height through the preset PLC program. If it has reached the preset height, proceed to step 6; otherwise, proceed to step 7. Step 6: The slab oscillates in front of the second mill stand in the roughing rolling area, that is, the slab moves forward for a period of time in front of the mill, and then moves backward for a period of time, without entering the mill for rolling, waiting for the return to the furnace command; Step 7: If the warpage height of the slab to be tested is normal and no alarm message is issued, proceed with normal rolling.

2. The method for detecting warping of rough-rolled slabs according to claim 1, characterized in that, In step 3, the 4-20mA signal output by the slab height detection device is transmitted to the preset PLC program, and the real-time slab height information of the slab to be tested is calculated based on the output 4-20mA signal.

3. The method for detecting warping of rough-rolled slabs according to claim 1, characterized in that, In step 3, when the detection height is greater than the preset value, the detection length of the plate is calculated by integrating the roller speed. When the detection length is greater than a certain value, the screening height is stopped.

4. The method for detecting warping of rough-rolled slabs according to claim 1, characterized in that, In step 4, the roll gap between the two work rolls is recorded during slab rolling, and this roll gap is the actual thickness of the slab.

5. The method for detecting warping of rough-rolled slabs according to claim 1, characterized in that, In step 6, when the slab is not rolled on the mill, an alarm is triggered by an alarm unit. The user confirms the actual warping height of the slab. If the detection matches the actual height, the slab cannot be rolled and must be returned to the slab warehouse.

6. The method for detecting warping of rough-rolled slabs according to claim 1, characterized in that, The absolute height Δh is 300mm.

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