Method for preventing rear-end collision of strip steel in coiling area

Abstract

The invention relates to a method for preventing rear-end collision of strip steel in a coiling area. The method comprises the steps of collecting data, calculating safety time, feeding back the safety time, adjusting the speed of a finishing mill and the like. According to the method for preventing the rear-end collision of the strip steel in the coiling area, the traditional mode that the rolling rhythm is given depending on artificial experience is changed, only the preparation time of coiling field equipment is accurately calculated, the steel feeding condition is automatically judged, the fastest rhythm does not need to be given manually, the dependence on manpower is changed, and the production efficiency is improved. And the labor intensity of operators is reduced, the automatic steel rolling level is improved, and meanwhile, steel scrap accidents caused by inaccurate rolling rhythm calculation are avoided. Through a process control program, accurate tracking of the head and tail positions of the strip steel is achieved, automatic speed keeping or speed reduction is achieved through program judgment, effective automatic feedback control is provided for uncertainty of process control, and deep promotion of the extreme cost of a company on the production line is boosted.

Description

Technical Field

[0001] The invention relates to a method for preventing strip steel from rear-ending in a coiling area, and belongs to the technical field of hot rolling. Background Art

[0002] In the process of hot rolling production of strip steel, in order to pursue ultimate efficiency and reduce costs, the production line will continuously improve the rolling rhythm of the production line, resulting in the gap time between the two pieces of steel becoming shorter and shorter. However, as the gap time shortens, the tail of the upper piece of steel and the head of the lower piece of steel can easily appear on the laminar cooling roller at the same time. Since the tail of the previous piece of steel needs to be reduced to a certain speed to enter the coiler for tail setting, and the speed of the next piece of steel continues to move according to the set speed of finishing rolling, the distance between the two pieces of steel on the laminar cooling roller becomes shorter and shorter, which may cause the head of the next piece of steel to catch up with the tail of the previous piece of steel. Even if it cannot catch up with the previous piece of steel, it may also cause insufficient equipment preparation time for the other coiler, resulting in steel stringing.

[0003] There are two traditional methods. One is to set a sufficient interval time for the finishing mill to catch up with the previous piece of steel, but this method may cause waste due to too long protection time; the other is to manually reduce the speed of the finishing mill when the next piece of steel is on the laminar cooling roller table and judge that it may be rear-ended, but this method requires a high sense of responsibility and experience of the operator and is not easy to implement. Once rear-end collision or steel stringing occurs, scrap steel will be generated, resulting in scrap steel from the finishing mill to the coiler, which is extremely difficult to handle and generally takes more than 2 hours to handle. Summary of the invention

[0004] The technical problem to be solved by the present invention is: to overcome the disadvantages of the above-mentioned technology and provide a method for automatically calculating the safety distance and performing feedback to control the finishing mill in real time, thereby avoiding the rear-end collision of the strip in the coiling area.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: a method for preventing the strip from rear-ending in the coiling area, comprising the following steps: (1) When the tail of the first steel piece leaves the finishing mill stand, collect the following data: the distance L1 between the tail of the first steel piece and the finishing mill stand, the width W1 of the first steel piece, the reel speed V of the other coiler DC2 , the speed of the pinch roll of the other coiler is V PR2 , the speed V of the auxiliary roll of the other coiler WR2 , the position of the pinch roll of the other coiler P PR2 , the width of the next piece of steel W2, the distance between the head of the next piece of steel and the finishing mill stand L2, the speed of the finishing mill stand of the next piece of steel V FMX ; (2) The side guide setting time is recorded as t1. When W2-W1≤0mm, t1=0 seconds. When W2-W1>0mm, t1=(W2-W1) / x1, where x1 is the slope of the side guide position loop. The time for the pinch roller to descend is t2, t2=P PR2 / x2, where x2 is the action slope of the pinch roller position ring; The time for the reel to increase speed is recorded as t3, t3=(V DC2 -V0) / a DC , where a DC is the reel lifting rate, V0 is the standby speed of the reel; The time for the pinch roller to increase its speed is recorded as t4, t4=(V PR2 -V1) / a PR , where a PR is the pinch roller lifting rate, V1 is the standby speed of the pinch roller; The time for the auxiliary roll to increase its speed is recorded as t5, t5=(V WR2 - V2) / a WR , where a WR is the lifting rate of the auxiliary winding roller, V2 is the standby speed of the auxiliary winding roller; (3) Take the maximum value T max (t1, t2, t3, t4, t5); (4) When the next piece of steel starts to bite the steel in the finishing mill, calculate the distance between the tail of the previous piece of steel and the head of the next piece of steel, that is, △L=L1-L2, and set T S Recorded as the safety time of the two steel pieces, T S =△L / V FMX ; If T S >T max +2 seconds, the finishing speed remains unchanged; If T max <T S ≤T max +2 seconds, the finishing speed remains unchanged and speed increase is prohibited; If T S ≤T max , then the finishing mill stand is a FM The deceleration rate is used to reduce the speed, and T is calculated continuously during this process. S Is it greater than T max , until T S Greater than T max Then stop decelerating, where a FM It is a fixed deceleration slope set for the system.

[0006] The present invention provides a method for preventing the strip from rear-ending in the coiling area, which changes the traditional method of relying on manual experience to set the rolling rhythm, and only accurately calculates the preparation time of the coiling site equipment to realize automatic judgment of the steel feeding conditions, without the need to manually set the fastest rhythm. It not only changes the dependence on manual labor, reduces the labor intensity of operators, and improves the level of automated steel rolling, but also prevents the occurrence of scrap steel accidents caused by inaccurate calculation of the rolling rhythm. Through the process control program, the precise tracking of the head and tail positions of the strip is achieved, and the automatic speed maintenance or speed reduction is achieved by relying on program judgment, which provides effective automatic feedback control for the uncertainty of process control, and promotes the company's extreme cost in-depth promotion in the production line. Implementation

[0007] Embodiment: The method for preventing the strip from rear-ending in the coiling area of ​​this embodiment comprises the following steps: (1) When the tail of the first steel piece leaves the finishing mill stand, collect the following data: the distance L1 between the tail of the first steel piece and the finishing mill stand, the width W1 of the first steel piece, the reel speed V of the other coiler DC2 , the speed of the pinch roll of the other coiler is V PR2 , the speed V of the auxiliary roll of the other coiler WR2 , the position of the pinch roll of the other coiler P PR2 , the width of the next piece of steel W2, the distance between the head of the next piece of steel and the finishing mill stand L2, the speed of the finishing mill stand of the next piece of steel V FMX ; (2) The side guide setting time is recorded as t1. When W2-W1≤0mm, t1=0 seconds. When W2-W1>0mm, t1=(W2-W1) / x1, where x1 is the slope of the side guide position loop. The time for the pinch roller to descend is t2, t2=P PR2 / x2, where x2 is the action slope of the pinch roller position ring; The time for the reel to increase speed is recorded as t3, t3=(V DC2 -V0) / a DC , where a DC is the reel lifting rate, V0 is the standby speed of the reel; The time for the pinch roller to increase its speed is recorded as t4, t4=(V PR2 -V1) / a PR , where a PR is the pinch roller lifting rate, V1 is the standby speed of the pinch roller; The time for the auxiliary roll to increase its speed is recorded as t5, t5=(V WR2 - V2) / a WR , where a WR is the lifting rate of the auxiliary winding roller, V2 is the standby speed of the auxiliary winding roller; (3) Take the maximum value T max (t1, t2, t3, t4, t5); (4) When the next piece of steel starts to bite the steel in the finishing mill, calculate the distance between the tail of the previous piece of steel and the head of the next piece of steel, that is, △L=L1-L2, and set T S Recorded as the safety time of the two steel pieces, T S =△L / V FMX ; If T S >T max +2 seconds, the finishing speed remains unchanged; If T max <T S ≤T max +2 seconds, the finishing speed remains unchanged and speed increase is prohibited; If T S ≤T max , then the finishing mill stand is a FM The deceleration rate is used to reduce the speed, and T is calculated continuously during this process. S Is it greater than T max , until T S Greater than T max Then stop decelerating, where a FM It is a fixed deceleration slope set for the system.

[0008] A specific application case is used as an example to illustrate.

[0009] Take the ordinary cold-rolled product AP1361C1 of Meishan Steel 1422 hot-rolled specifications of 3.0mm*950mm and 2.5mm*1100mm as an example.

[0010] Step 1: The data acquisition module collects the following strip data: the distance between the tail of the first piece of steel and the finishing mill stand is 90m, the coil speed is 7.5m / s, the width is 950mm, the coil speed of another coiler is 2m / s, the pinch roller speed of another coiler is 2m / s, the auxiliary coiling roller speed of another coiler is 2m / s, the width of the next piece of steel is 1100mm, the pinch roller position of another coiler is 250mm, the distance between the head of the second piece of steel and the finishing mill stand is 3m, and the finishing mill stand speed of the second piece of steel is 11m / s.

[0011] Step 2: Calculate the following data in real time based on the strip data collected in step 1: ① Side guide setting time (t1), when W2-W1≤0mm, the side guide setting time is recorded as 0 seconds, when W2-W1>0mm=Xmm, the side guide time is recorded as t1, t1=X / x1, where x1 is the slope of the side guide position loop; at this time, the applicable rule is W2-W1>0mm, that is, 1100mm-950mm=150mm, the side guide action rate is 50mm / second, then t1=150 / 50=3 seconds.

[0012] ② Pinch roller descending time (t2), t2=P PR2 / x2, where x2 is the action slope of the pinch roller position ring; the pinch roller position is 250mm, the action slope is 50mm / second, then t2=250 / 50=5 seconds.

[0013] ③ Roll speed up time (t3), V DC2 -V0=a DC *t3, where a DC is the roll lifting rate, then t3=(V DC2 -V0) / a DC The standby speed of the reel is 2m / s, and the bite speed of the next steel piece is set to 110% of the speed of the final stand of the finishing rolling mill. The set speed is 11*110%, and the reel lifting rate is 1.5m / S 2 , then t3=(11*110%-2) / 1.5=6.73 seconds.

[0014] ④ Pinch roller speed-up time (t4), V PR2 -V0=a PR *t4, where a PR is the pinch roller lifting rate, then t4=(V PR2 -V0) / a PR The standby speed of the pinch roller is 2m / s, and the bite speed of the next steel piece is set to 110% of the speed of the final stand of the finishing rolling mill. The set speed is 11*110%, and the coil lifting rate is 2.0m / S 2 , then t4=(11*110%-2) / 2=5.05 seconds.

[0015] ⑤ Winding roller speed up time (t5), V WR2 -V0=a WR *t5, where a WR is the lifting rate of the auxiliary winding roller, then t5=(V WR2 -V0) / a WR The standby speed of the auxiliary roll is 2m / s, the bite speed of the next steel piece is set to 150% of the speed of the final stand of the finishing rolling mill, then the set speed is 11*170%, and the roll lifting rate is 2.0m / S 2 , then t5=(11*150%-2) / 2=8.35 seconds.

[0016] In this embodiment, V0=V1=V2, and therefore V0 is used instead.

[0017] Step 3: After all the data in step 2 are calculated, take the maximum value T max (t1, t2, t3, t4, t5); the maximum value T obtained based on the above data max (3, 5, 6.73, 5.05, 8.35) is 8.35 seconds.

[0018] Step 4: When the next piece of steel starts to bite the steel in the finishing mill, the distance between the tail of the previous piece of steel and the head of the next piece of steel is calculated in real time, that is, L △L = L1-L2, T S Recorded as the safety time of the two pieces of steel, the ultimate safety time is, T S =L △L / V FMX When F6 bites the steel, the head tracking is recorded as 0m, and the tail tracking of the previous piece is 90m. At this time, the distance between the two steel pieces is 90m, and the maximum safety time is T S =L △L / V FMX =90 / 11=8.18 seconds.

[0019] Step 5: Calculate T in real time when the next piece of steel finishing mill starts biting steel S ; If T S >T max +2 seconds, the finishing speed control remains unchanged; If T max <T S ≤T max +2 seconds, the finishing speed is locked at the current speed and speed increase is prohibited; If T S ≤T max , then the finishing mill stand is a FM The deceleration rate is used to reduce the speed, and T is calculated continuously during this process. S Is it greater than T max , until T S Greater than T max Then stop decelerating, where a FM It is a fixed deceleration slope set for the system.

[0020] At this time T S = 8.18 seconds, T S (8.18 seconds)<T max (8.35 seconds), the finishing speed is triggered to slow down. At this time, the finishing mill group is running at 1m / S 2 The acceleration starts to decelerate and decelerates to T S= (91-1) / 10.9 = 8.35 seconds, and the speed is maintained until the coiler bites the steel.

[0021] The present invention is not limited to the above embodiments. Any technical solution formed by equivalent replacement falls within the protection scope required by the present invention.

Claims

1. A method for preventing strip steel from rear-ending in a coiling area, characterized in that: The steps include: (1) When the tail of the first steel piece leaves the finishing mill stand, collect the following data: the distance L1 between the tail of the first steel piece and the finishing mill stand, the width W1 of the first steel piece, the reel speed V of the other coiler DC2 , the speed of the pinch roll of the other coiler is V PR2 , the speed V of the auxiliary roll of the other coiler WR2 , the position of the pinch roll of the other coiler P PR2 , the width of the next piece of steel W2, the distance between the head of the next piece of steel and the finishing mill stand L2, the speed of the finishing mill stand of the next piece of steel V FMX ; (2) The side guide setting time is recorded as t1. When W2-W1≤0mm, t1=0 seconds. When W2-W1>0mm, t1=(W2-W1) / x1, where x1 is the slope of the side guide position loop. The time for the pinch roller to descend is t2, t2=P PR2 / x2, where x2 is the action slope of the pinch roller position ring; The time for the reel to increase speed is recorded as t3, t3=(V DC2 -V0) / a DC , where a DC is the reel lifting rate, V0 is the standby speed of the reel; The time for the pinch roller to increase its speed is recorded as t4, t4=(V PR2 -V1) / a PR , where a PR is the pinch roller lifting rate, V1 is the standby speed of the pinch roller; The time for the auxiliary roll to increase its speed is recorded as t5, t5=(V WR2 - V2) / a WR , where a WR is the lifting rate of the auxiliary winding roller, V2 is the standby speed of the auxiliary winding roller; (3) Take the maximum value T max (t1, t2, t3, t4, t5); (4) When the next piece of steel starts to bite the steel in the finishing mill, calculate the distance between the tail of the previous piece of steel and the head of the next piece of steel, that is, △L=L1-L2, and set T S Recorded as the safety time of the two steel pieces, T S =△L / V FMX ; If T S >T max +2 seconds, the finishing speed remains unchanged; If T max <T S ≤T max +2 seconds, the finishing speed remains unchanged and speed increase is prohibited; If T S ≤T max , then the finishing mill stand is a FM The deceleration rate is used to reduce the speed, and T is calculated continuously during this process. S Is it greater than T max , until T S Greater than T max Then stop decelerating, where a FM It is a fixed deceleration slope set for the system.