A tail-dropping method for thin-gauge switching production mode of continuous casting and rolling production line

Abstract

This invention discloses a method for strip tailings during thin-gauge switching production in a continuous casting and rolling line, belonging to the field of steel production technology, including: (1) calculating the real-time strip thickness h and the unloaded roll gap h0; (2) calculating the strip speed: calculating one by one to obtain the strip speed V at the exit of each rolling mill. ex and the strip speed V at the mill inlet en (3) Dynamic throwing frame control: In case of abnormality, manually trigger the swing shear shear, and the tail of the virtual track is 7-12 meters away from the F1 mill. The F5 mill starts the throwing frame function; the mill roll gap control switches from position control mode to rolling force control mode, and the rolling force decreases; when the actual rolling force decreases to 1MN, switch back to position control mode: the position is opened to h en +h0+remaining value, and simultaneously, the #4 looper device drops to the low position, and the machine frame is thrown out sequentially according to the above control mode. Compared with existing technologies, it has the characteristics of reliability, high efficiency, and low loss.

Description

Technical Field

[0001] This invention belongs to the field of steel production technology and relates to a new method for tailings during thin-gauge switching production in continuous casting and rolling production lines. Background Technology

[0002] The continuous casting production line consists of a continuous casting machine, a roughing mill, a slewing shear, a finishing mill, and a coiler. After the entire continuous casting and rolling production line starts rolling, it enters a headless mode to produce steel coils, meaning that the entire line produces the same strip of steel, and all equipment is in series, with no head. The automation program tracks the strip based on speed, heat detection, etc. The control program sets the action sequence based on the calculated virtual tracking. That is, when the virtual head and tail reach the high-speed flying shear in front of the coiler, the flying shear starts to cut, and the strip is coiled.

[0003] Because the rolling mill and continuous casting machine are rigidly connected in the steel coil production mode, and in the headless mode for producing steel coils with a thickness h < 3.0mm, there is a significant risk of tail breakage due to the continuous headless rolling of multiple coils in case of emergencies such as sudden quality or equipment problems. Therefore, when a fault occurs in a series of equipment in either region and a shutdown is required, the general procedure is to directly press the quick stop button or press the quick stop button at the front of the finishing mill. After the Q-STOP signal is issued, the finishing mill and coiling quick stop are initiated, the equipment stops, and the production mode is switched from steel coil mode to slab production mode. At this time, the strip steel between the swing shear and the finishing mill, flying shear, and coiling machine needs to be cut off and converted into scrap steel, approximately 10 tons per batch.

[0004] The process of returning from quick stop mode to ready state requires powering on each piece of equipment and switching to automatic mode. Only after all equipment is ready can the process be switched to steel coil production mode. This switching takes 20 minutes and affects operational efficiency. Summary of the Invention

[0005] The technical objective of this invention is to address the shortcomings of the prior art by providing a tailings disposal method for switching production modes of thin specifications in continuous casting and rolling production lines, thereby shortening accident handling time and improving operational efficiency.

[0006] The technical solution of this invention to solve its technical problem is: a method for tailings removal in the thin-gauge switching production mode of a continuous casting and rolling production line, characterized in that it includes:

[0007] (1) Calculate the real-time strip thickness h and the unloaded roll gap h0: calculate the inlet thickness hen and outlet thickness hex of each mill one by one;

[0008] (2) Calculate the strip speed: Calculate the strip speed V at the exit of each rolling mill. ex and the strip speed V at the mill inlet en ;

[0009] (3) Dynamic shearing control: In case of abnormality, manually trigger the swing shear, and when the tail of the virtual track is 7-12 meters away from the F1 mill, the F5 mill will activate the shearing function; the mill roll gap control will switch from position control mode to rolling force control mode, and the rolling force will decrease; when the actual rolling force decreases to 1MN, switch back to position control mode: the position is opened to h en +h0+remaining value, and at the same time, the No. 4 looper looper device falls to the low position. According to the above control mode, after the looper falls to the low position, the previous frame executes the throwing frame according to the same logic until the F2 throwing frame is completed, and F1 forms tension with the winding machine.

[0010] Furthermore, the formula for calculating the real-time thickness h of the strip is as follows:

[0011]

[0012] Among them: the mill stiffness coefficient Cg, the mill roll gap reading Gap, the mill rolling force F, and the cumulative roll wear S accumulated by process automation. wear , Roll thermal expansion S the .

[0013] Furthermore, the formula for calculating the unloaded roll gap h0 of the aforementioned roll contact is as follows:

[0014]

[0015] Wherein: the stiffness coefficient Cg of the rolling mill.

[0016] Furthermore, the above-mentioned method for calculating strip speed is as follows: the rotational speed of the looper rolls is detected by the angular velocity encoder at the end of the looper rolls between the rolling mills, and the strip linear speed is calculated based on the looper roll diameter and angular velocity.

[0017] Furthermore, the above-mentioned method for calculating strip speed is as follows: V is calculated using the front and rear slip coefficients and the finishing mill speed. ex and rolling V en .

[0018] Furthermore, the aforementioned V ex and rolling V en The calculation formula is:

[0019] V ex =V·K lead

[0020] V en =V·K lag

[0021] Where V is the mill speed K lead K represents the forward slip value during the rolling process. lag Slip value after rolling process.

[0022] Furthermore, in the aforementioned dynamic mill stand control, the formula for mill speed control is:

[0023] Speed ​​correction V = (V5 - V) 5en )·K

[0024] Among them, the launcher coefficient K ranges from 0 to 100%; after the launcher starts, it integrates from 0 to 100%.

[0025]

[0026] Wherein, time t.

[0027] Furthermore, the mill before the stand-off is controlled by the last activated stand as the master speed control; after the stand-off timing is started, the master speed is moved forward to the previous stand to ensure that the stand-off process does not affect the production status of the upstream stand.

[0028] Compared with the prior art, the present invention has the following outstanding advantages:

[0029] 1. When the continuous casting and rolling production line is in the steel coil production mode and is urgently switched to the slab production mode, the swing shear is used for shearing and cutting, and the finishing mill throws the strip steel out of the mill one by one from back to front, thus directly meeting the ready conditions, shortening the accident handling time by 15 minutes / time, and improving the operation efficiency.

[0030] 2. Reduce scrap steel production to avoid direct economic losses. Detailed Implementation

[0031] The present invention will be further described below with reference to specific embodiments.

[0032] For the purposes of the following detailed description, it should be understood that the invention may take various alternative variations and sequences of steps unless explicitly stated otherwise. Furthermore, except in any operational instance or where otherwise indicated, all figures representing quantities of ingredients as used, for example, in the specification and claims, should in all cases be understood to be modified by the term “about.” At least, and without attempting to limit the application of the principle of equivalents to the scope of the claims, each numerical parameter should be understood at least according to the number of significant figures reported and by applying common rounding techniques.

[0033] Although the numerical ranges and parameters illustrating the broad scope of the invention are approximate, the values ​​described in the specific examples are reported as precisely as possible. However, any numerical value inherently contains some error that is necessarily caused by the standard deviation found in its corresponding test measurement.

[0034] It should also be understood that any range of values ​​stated herein is intended to include all subranges included therein. For example, the range “1 to 10” is intended to include all subranges between (and including) the stated minimum value of 1 and the stated maximum value of 10, that is, a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.

[0035] In this application, unless otherwise specified, the use of the singular includes the plural and the plural encompasses the singular. Additionally, in this application, unless otherwise expressly stated, the use of "or" means "and / or," even if "and / or" may be explicitly used in certain circumstances. Furthermore, in this application, unless otherwise specified, the use of "a" or "an" means "at least one / a." For example, "an" first material, "an" coating composition, etc., refer to one or more of any of these items.

[0036] This invention is used in continuous casting and rolling production lines to switch urgently to slab production mode when producing steel coils. The shear performs cutting and slitting, and the finishing mill throws the strip out of the mill one stand at a time from back to front, thus directly achieving the ready conditions.

[0037] This invention is used in continuous casting and rolling production lines. A looper device is installed between the finishing mills to maintain the tension between the stands and detect the amount of strip. An angular velocity encoder is installed at the end of the looper roll to detect the rotational speed of the looper roll and to calculate the strip line speed.

[0038] This invention relates to a method for tailings removal during thin-gauge switching production in a continuous casting and rolling line, specifically comprising:

[0039] 1. Calculate the real-time strip thickness and unloaded roll gap.

[0040] (1) Real-time thickness h of the strip

[0041] Given the mill's stiffness coefficient Cg, the mill's roll gap reading (after calibration with 1000 tons of rolling force) Gap, the mill's rolling force F, and the cumulative roll wear S accumulated during the automated process. wear , Roll thermal expansion S the The real-time thickness h of the strip is calculated using the following thickness measurement equation:

[0042]

[0043] (2) The unloaded roll gap h0 of the roll contact

[0044]

[0045] Current rack inlet thickness h en The exit thickness h of the previous stand rolling ex , such as hex1 =h en2 .

[0046] The inlet thickness h of each rolling mill is obtained. en and export thickness h ex :

[0047]

[0048]

[0049]

[0050]

[0051]

[0052] 2. Calculate the strip speed

[0053] The first finishing mill stand, F1, is closest to the roughing mill. The remaining finishing mill stands are numbered F1, F2, F3, F4, and F5, respectively. The mills before the scrambling stand are controlled by the last activated stand as the master speed. After initiating the scrambling stand sequence, the master speed is moved forward to the previous stand to ensure that the scrambling stand process does not affect the production status of the upstream stands.

[0054] After the strip speed is started, the strip speed is calculated by detecting the rotational speed of the looper rolls at the ends of the looper rolls between the rolling mills, and then calculating the strip linear speed based on the looper roll diameter and angular velocity. The calculation formula for this part is existing technology and will not be elaborated here.

[0055] However, the method described in this application is designed for emergencies such as sudden quality or equipment problems. If the looper encoder malfunctions, the aforementioned angular velocity measurement method becomes unreliable. In this case, the front and rear slip coefficients and the finishing mill speed are used to calculate the mill inlet and outlet speeds. Details are as follows:

[0056] (1) Calculate the strip speed V at the mill exit. ex :

[0057] V ex =V·K lead

[0058] (2) Calculate the strip velocity V at the mill inlet. en :

[0059] V en =V·K lag

[0060] Where V represents the speed of the F1-5 rolling mill, V1, V2…V5, and K… lead K represents the forward slip value during the rolling process. lag Slip value after rolling process.

[0061] The strip speed V at the exit of each rolling mill is calculated one by one. ex and the strip speed V at the mill inlet en .

[0062] 3. Dynamic throwing frame control

[0063] In case of abnormality, the roughing mill operator manually triggers the swing shear to cut the shear. The tail of the virtual track is 7-12 meters away from the F1 mill, and the F5 stand starts the throwing frame function.

[0064] (1) Rolling mill speed control

[0065] Speed ​​correction V = (V5 - V) 5en )·K

[0066] Among them, the launcher coefficient K ranges from 0 to 100%; after the launcher starts, it integrates from 0 to 100%.

[0067]

[0068] Wherein, time t.

[0069] (2) Switching of roll gap control logic mode

[0070] In the continuous casting and rolling production line, when producing steel coils, the mill roll gap control is in position control mode. After starting the blasting stand sequence, the roll gap control switches to rolling force control mode, and the rolling force is reduced.

[0071] After the rolling mill is completed, the rolling force is 0, and the total decrease in rolling force ΔF is equal to the actual rolling force value recorded at the time of the rolling mill's logical start.

[0072] During the rolling mill process, the total decrease in rolling force ΔF increases with time. When the actual rolling force decreases to 1MN, the system switches back to position control mode: the position is opened to h. en +h0+remaining value, and at the same time, the 4# looper device falls to the low position, at which point F4 and the winding machine automatically form tension.

[0073] In this embodiment, the specific steps are: opening to h at a speed of 2mm / s. en +h0+20mm.

[0074] According to the above control mode, after the looper falls to the low position, the previous frame executes the throwing frame according to the same logic until the F2 throwing frame is completed, and F1 forms tension with the winding machine.

[0075] It should be noted that the specific embodiments of the present invention have been described in detail. For those skilled in the art, various obvious changes made to it without departing from the spirit and scope of the present invention are within the protection scope of the present invention.

Claims

1. A method for tailings removal during thin-gauge switching production mode in a continuous casting and rolling production line, characterized in that: include: (1) Calculate the real-time strip thickness h and the unloaded roll gap h0: Calculate the entrance thickness h of each mill one by one. en and export thickness h ex ; (2) Calculate the strip speed: Calculate the strip speed V at the exit of each rolling mill. ex and the strip speed V at the mill inlet en ; (3) Dynamic shearing control: In case of abnormality, the swing shear is manually triggered, and the tail of the virtual track is 17-12 meters away from the first finishing mill. The fifth finishing mill F5 starts the shearing function; the mill roll gap control switches from position control mode to rolling force control mode, and the rolling force decreases; when the actual rolling force decreases to 1MN, it switches back to position control mode: the position is opened to h. en +h0+remaining value, and at the same time, the looper device of looper No. 4 falls to the low position. According to the above control mode, after the looper falls to the low position, the previous stand executes the throwing stand according to the same logic until the second finishing mill F2 throwing stand is completed, and F1 forms tension with the coiler.

2. The tailings removal method for switching thin-gauge production modes in a continuous casting and rolling production line according to claim 1, characterized in that: The formula for calculating the real-time thickness h of the strip is: ， Among them: the mill stiffness coefficient Cg, the mill roll gap reading Gap, the mill rolling force F, and the cumulative roll wear S accumulated by process automation. wear , Roll thermal expansion S the .

3. The tailings removal method for switching thin-gauge production modes in a continuous casting and rolling production line according to claim 1, characterized in that: The formula for calculating the unloaded roll gap h0 of the roll contact is: ， Wherein: the stiffness coefficient Cg of the rolling mill.

4. The tail-end removal method for switching thin-gauge production modes in a continuous casting and rolling production line according to claim 1, characterized in that: The method for calculating the strip speed is as follows: the rotational speed of the looper rolls is detected by the angular velocity encoder at the end of the looper rolls between the rolling mills, and the strip linear speed is calculated based on the looper roll diameter and angular velocity.

5. The tail-end removal method for switching thin-gauge production modes in a continuous casting and rolling production line according to claim 1, characterized in that: The method for calculating the strip speed is as follows: V is calculated using the front and rear slip coefficients and the finishing mill speed. ex and rolling V en .

6. The tail-end removal method for switching thin-gauge production modes in a continuous casting and rolling production line according to claim 5, characterized in that: The V mentioned ex and rolling V en The calculation formula is: Vex = V·K lead Ven=V·K lag Where V is the mill speed, K lead K represents the forward slip value during the rolling process. lag Slip value after rolling process.

7. The tail-end removal method for switching thin-gauge production modes in a continuous casting and rolling production line according to claim 1, characterized in that: In the aforementioned dynamic rolling mill stand control, the formula for mill speed control is: Speed ​​correction V = (V5 - V) 5en )·K Where V5 is the mill speed of the fifth finishing mill F5, V 5en The strip speed at the entrance of the fifth finishing mill (F5), and the shovel coefficient K, ranges from 0 to 100%; after the shovel is started, the coefficient increases from 0 to 100%. ， Wherein, time t.

8. The tail-end removal method for switching thin-gauge production modes in a continuous casting and rolling production line according to claim 1, characterized in that: The mill before the stand-off is controlled by the last activated stand as the master speed control. After the stand-off timing is started, the master speed is moved forward to the previous stand to ensure that the stand-off process does not affect the production status of the upstream stand.

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