Method for improving the stable operation of a strip seam in a gas cushion furnace

Abstract

The application provides a method for improving the stable operation of a strip seam in an air cushion furnace, which comprises a seam detection position arranged at a roller way in front of an air cushion furnace entrance, and a PLC controller connected with a seam detector and a tension roller group of the seam detection position; when the strip seam passes through the seam detection position, the PLC controller acquires the tension values of the front and rear strip coils through a tension detection sensor at the tension roller group, and adjusts the motor working condition of the tension roller group before the seam enters the air cushion furnace, so that the tension output of the tension roller is adjusted in a gradient control mode, the tension value of the front strip coil is gradually adjusted, and the tension value of the front strip coil is consistent with that of the rear strip coil; the application can gradually change the strip tension according to the tension difference between the front and rear strip coils before the seam enters the furnace.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal processing, and particularly relates to a method for improving stable operation of a strip seam in a gas cushion furnace. BACKGROUND

[0002] If a normal product of a strip is connected in sequence by splicing multiple strips, there may be a situation that the tension of the front strip and the tension of the rear strip are inconsistent during the continuous annealing line production. That is, the total tension of the front strip and the total tension of the rear strip are inconsistent. Since the strip in the gas cushion furnace is very sensitive to the change of the tension, the strip is very easy to deviate and scratch the furnace wall, thereby causing the strip to break in the furnace. At this time, the tension control logic under the traditional mode needs to be increased or decreased to the tension value of the rear strip at the moment when the seam enters the gas cushion furnace.

[0003] However, it is found in actual operation that the tension should not be changed instantaneously when the seam passes through the front of the gas cushion furnace, the rear of the gas cushion furnace and the middle of the furnace cavity of the gas cushion furnace, and the tension should be changed gradually before the seam enters the furnace. However, it is difficult to ensure that each strip is processed accurately according to the same process by relying on manual operation. Therefore, the present application provides a method for improving stable operation of a strip seam in a gas cushion furnace. SUMMARY

[0004] The present application provides a method for improving stable operation of a strip seam in a gas cushion furnace, which can change the tension of the strip gradually before the seam enters the furnace according to the difference in the tension of the strip before and after the seam.

[0005] A method for improving stable operation of a strip seam in a gas cushion furnace, the strip is connected and formed by a front strip and a rear strip at the seam, and is sent to the gas cushion furnace by a roller table with a tension roller group to perform annealing treatment. Before the seam enters the gas cushion furnace, the tension values of the front strip and the rear strip are different. The method comprises a seam detection position arranged at the roller table in front of the inlet of the gas cushion furnace, and further comprises a seam detector of the seam detection position, a PLC controller connected with the seam detector and the tension roller group. When the seam of the strip passes through the seam detection position, the PLC controller obtains the tension values of the front strip and the rear strip through a tension detection sensor at the tension roller group, and adjusts the working condition of the motor of the tension roller group before the seam enters the gas cushion furnace, so as to adjust the tension output of the tension roller in a gradient control mode and gradually adjust the tension value of the front strip, so that the tension value of the front strip is consistent with the tension value of the rear strip.

[0006] The tension roller group comprises a first tension roller group located in front of a B point of the inlet of the gas cushion furnace, and further comprises a second tension roller group located behind a C point of the outlet of the gas cushion furnace.

[0007] The first tension roller group and the second tension roller group are used for adjusting the tension of the strip at the gas cushion furnace, and both of the tension roller groups use an alternating current motor as a power source.

[0008] The first tension roller set and the second tension roller set each comprise a tension roller, a speed reducer and an alternating current motor, the alternating current motor being used to drive the tension roller to rotate; the speed reducer adjusts the output torque by adjusting the rotating speed of the alternating current motor; the tension roller applies tension to the strip by applying resistance to the strip when the strip passes through.

[0009] The first tension roller set comprises a No.1-1 tension roller and a No.1-2 tension roller arranged in sequence in the strip conveying direction; the second tension roller set comprises a No.2-1 tension roller, a No.2-2 tension roller, a No.2-3 tension roller and a No.2-4 tension roller arranged in sequence in the strip conveying direction; after the splicing joint passes through the air cushion furnace for annealing treatment, the splicing joint reaches a stable state when running to the D point of the No.2-2 tension roller;

[0010] The splicing joint detector is arranged at the A point of the No.1-1 tension roller; a tension meter is arranged at the No.1-2 tension roller, the tension meter comprising a tension controller and a plurality of tension detection sensors;

[0011] The tension detection sensors are arranged on the roller seats on the operating side and the transmission side of the No.1-2 tension roller, and are used to detect the tension value of the roller seats along the strip direction;

[0012] The tension controller is connected with the tension detection sensors, the PLC controller and the alternating current motors of the tension roller sets, and is used to receive and convert the tension value detected by the tension detection sensors, and send the converted tension value to the PLC controller; meanwhile, the tension controller can receive the tension given value of the PLC controller, and control the alternating current motor of the No.1-2 tension roller according to the tension given value to adjust the tension output of the tension roller.

[0013] The PLC controller calculates the tension given value of the No.1-2 tension roller by using the PID control method, and the calculation method of the proportional coefficient Kp value of the PID control method comprises the following steps:

[0014] Step S1: when the PLC controller detects the position of the splicing joint at the A point, the time t1 required for the splicing joint to run to the B point at the inlet of the air cushion furnace is set as L1 / V1; the time t2 required for the splicing joint to pass through the entire air cushion furnace from the B point at the inlet to the C point at the outlet of the air cushion furnace; the time t3 required for the splicing joint to reach the stable position D point after passing through the air cushion furnace;

[0015] Step S2: the PLC controller detects the tension of the strip before and after the splicing joint through the tension detection sensors; the tension value of the front winding strip is set as N1, and the tension value of the rear winding strip is set as N2; then the following formula is used to calculate:

[0016] N1=W1*T1*n1;

[0017] N2 = W2 * T2 * n2;

[0018] Kp = (N1 - N2) / (t1 + t2 + t3) ;

[0019] Kp = (W1 * T1 * n1 - W2 * T2 * n2) / (t1 + t2 + t3) ;

[0020] Step S3, when Kp > 0, the rotation condition of the motor is controlled by the PLC controller, and then the tension is increased from N1 to N2;

[0021] When Kp = 0, the tension remains unchanged;

[0022] When Kp < 0, the rotation condition of the motor is controlled by the PLC controller, and then the tension is decreased from N1 to N2;

[0023] In the above formula:

[0024] L1 is the position of the suture port detection position from the air cushion furnace inlet, unit: m;

[0025] L2 is the length of the air cushion furnace, unit: m;

[0026] L3 is the position of the air cushion furnace outlet to the safety area, unit: m;

[0027] V1 is the process speed of the front roll, unit: m / min;

[0028] V2 is the process speed of the rear roll, unit: m / min;

[0029] n1 is the process unit tension value of the front roll, unit: N;

[0030] n2 is the process unit tension value of the front roll, unit: N;

[0031] W1 is the width of the front roll strip, unit: mm;

[0032] W2 is the width of the rear roll strip, unit: mm;

[0033] T1 is the thickness of the front roll strip, unit: mm;

[0034] T2 is the thickness of the rear roll strip, unit: mm;

[0035] Kp is the proportion value in the PID tension control of the air cushion furnace tension control.

[0036] The air cushion furnace outlet C point and the 2-1 tension roller are provided with a deviation correction roller for controlling the attitude of the strip in the air cushion furnace; when the strip in the air cushion furnace deviates, the deviation correction roller moves to the equipment operation side or the transmission side to ensure that the strip runs in the center line range of the air cushion furnace;

[0037] The strip with the seam of the annealing treatment performed by the air cushion furnace has a superimposed seam structure of the front and rear coil strips, and the thickness of the seam is different from the thickness of the strip in front of and behind the seam;

[0038] The seam detector comprises a detection surface parallel to the surface of the strip formed by at least two laser measuring devices, and the arrangement direction of the two laser measuring devices is perpendicular to the running direction of the strip.

[0039] The method for detecting the seam by the PLC through the seam detector is as follows: when the strip passes through the detection area of the seam detector, if the distance between the detection surface of the seam detector and the surface of the strip is constant and the duration of the condition is greater than threshold A, it is determined that no seam passes through the seam detector; if the distance between the detection surface of the seam detector and the surface of the strip is suddenly changed and the duration of the condition is greater than threshold B, it is determined that a seam passes through the seam detector, and threshold A is much greater than threshold B.

[0040] The present application can change the tension gradually before, during and after the seam of the strip passes through the air cushion furnace, so that the posture and position of the strip are more stable when the strip passes through the air cushion furnace and is lifted by the air cushion in the furnace. BRIEF DESCRIPTION OF DRAWINGS

[0041] The present application will be further described in detail below in combination with the drawings and specific embodiments:

[0042] The accompanying drawings are schematic diagrams of the present application; Figure 1

[0043] The accompanying drawings are schematic diagrams of the present application; Figure 2 The accompanying drawings are schematic diagrams of the present application; DETAILED DESCRIPTION

[0044] ​As shown in the figure, a method for improving the stable operation of the seam of the strip in the air cushion furnace, the strip is connected and formed by the front and rear coil strips at the seam, and is sent to the air cushion furnace by the roller table of the tension roller group to perform annealing treatment, the tension values of the front and rear coil strips are different before the seam is sent to the air cushion furnace, the method comprises a seam detection position provided at the roller table before the entrance of the air cushion furnace, and further comprises a seam detector of the seam detection position, a PLC controller connected with the seam detector and the tension roller group, when the seam passes through the seam detection position, the PLC controller obtains the tension values of the front and rear coil strips through the tension detection sensor at the tension roller group, and adjusts the working condition of the motor of the tension roller group before the seam enters the air cushion furnace, so as to adjust the tension output of the tension roller in a gradient control mode, and gradually adjust the tension value of the front coil strip, so that the tension value of the front coil strip is consistent with the tension of the rear coil strip.

[0045] The tension roller group comprises a first tension roller group located before the entrance B point of the air cushion furnace, and a second tension roller group located behind the exit C point of the air cushion furnace;

[0046] The first and second tension roller groups are used to adjust the tension of the strip at the air cushion furnace, and both use an alternating current motor as a power source;

[0047] The first and second tension roller groups each comprise a tension roller, a speed reducer and an alternating current motor, the alternating current motor is used to drive the rotation of the tension roller, the speed reducer adjusts the output torque by adjusting the rotating speed of the alternating current motor, and the tension roller applies tension to the strip by applying resistance to the strip when the strip passes through.

[0048] The first tension roller group comprises a No. 1-1 tension roller and a No. 1-2 tension roller arranged in sequence in the conveying direction of the strip, the second tension roller group comprises a No. 2-1 tension roller, a No. 2-2 tension roller, a No. 2-3 tension roller and a No. 2-4 tension roller arranged in sequence in the conveying direction of the strip, and the seam reaches a stable state when running to the D point of the No. 2-2 tension roller after the annealing treatment in the air cushion furnace;

[0049] The seam detector is arranged at the A point of the No. 1-1 tension roller, and a tension meter is arranged at the No. 1-2 tension roller, the tension meter comprises a tension controller and a plurality of tension detection sensors;

[0050] The tension detection sensors are arranged on the roller seats on the operating side and the transmission side of the No. 1-2 tension roller, and are used to detect the tension value of the roller seat along the direction of the strip;

[0051] The tension controller is connected with the tension detection sensor, the PLC controller and the AC motor of the tension roller group, used for receiving and converting the tension value detected by the tension detection sensor, and sending the converted tension value to the PLC controller, and receiving the tension given value of the PLC controller, and controlling the AC motor of the No.1-2 tension roller according to the tension given value to adjust the tension output of the tension roller.

[0052] The PLC controller calculates the tension given value of the No.1-2 tension roller by the PID control method, and the calculation method of the proportional coefficient Kp value of the PID control method comprises the following steps:

[0053] Step S1, when the PLC controller detects the position of the seam at point A, at this time, the time t1 required for the seam to run to the air cushion furnace inlet point B is set as L1 / V1; the time t2 for the seam to pass through the entire air cushion furnace from the air cushion furnace inlet point B to the air cushion furnace outlet point C; the time t3 for the seam to pass through the air cushion furnace to the stable position D point;

[0054] Step S2, the PLC controller detects the strip tension before and after the seam through the tension detection sensor; the detected front coil strip tension value is N1, and the rear coil strip tension value is N2; then the formula is calculated to obtain:

[0055] N1=W1*T1*n1;

[0056] N2=W2*T2*n2;

[0057] Kp=(N1-N2) / (t1+t2+t3);

[0058] Kp=(W1*T1*n1-W2*T2*n2) / (t1+t2+t3);

[0059] Step S3, when Kp>0, the rotation working condition of the motor is controlled through the PLC controller, and then the tension is increased from N1 to N2;

[0060] When Kp=0, the tension remains unchanged;

[0061] When Kp<0, the rotation working condition of the motor is controlled through the PLC controller, and then the tension is decreased from N1 to N2;

[0062] In the above formula:

[0063] L1 is the position of the seam detection position away from the air cushion furnace inlet, with the unit of m;

[0064] L2 is the length of the air cushion furnace, with the unit of m;

[0065] L3 is the position of the air cushion furnace outlet to the safe area, with the unit of m;

[0066] V1 is the process speed of the front roll, in m / min;

[0067] V2 is the process speed of the back roll, in m / min;

[0068] n1 is the process unit tension value of the front roll, in N;

[0069] n2 is the process unit tension value of the back roll, in N;

[0070] W1 is the width of the front roll strip, in mm;

[0071] W2 is the width of the back roll strip, in mm;

[0072] T1 is the thickness of the front roll strip, in mm;

[0073] T2 is the thickness of the back roll strip, in mm;

[0074] Kp is the proportional value in the PID tension control of the air cushion furnace tension control.

[0075] A deviation correcting roller is arranged between the C point at the air cushion furnace outlet and the No. 2-1 tension roller, for controlling the attitude of the strip in the air cushion furnace; when the strip in the air cushion furnace deviates, the deviation correcting roller moves to the equipment operation side or the transmission side, to ensure that the strip runs in the center line range of the air cushion furnace.

[0076] The strip sent into the air cushion furnace for annealing treatment has a spliced joint of the superimposed splicing structure of the front roll strip and the back roll strip, and the thickness of the spliced joint is different from the thickness of the strip in front of and behind the spliced joint.

[0077] The spliced joint detector includes a detection surface parallel to the surface of the strip, which is formed by at least two laser measuring devices; the arrangement direction of the two laser measuring devices is perpendicular to the running direction of the strip; the PLC detects the distance between the detection surface of the spliced joint detector and the surface of the strip through the two laser measuring devices.

[0078] The method for detecting the spliced joint by the PLC through the spliced joint detector is as follows: when the strip passes through the detection area of the spliced joint detector, if the distance between the detection surface of the spliced joint detector and the surface of the strip is unchanged and the situation lasts for a time longer than a threshold value A, it is determined that no spliced joint passes through the spliced joint detector; if the distance between the detection surface of the spliced joint detector and the surface of the strip suddenly changes and the situation lasts for a time longer than a threshold value B, it is determined that a spliced joint passes through the spliced joint detector, and the threshold value A is much larger than the threshold value B.

[0079] Embodiment:

[0080] In this example, according to the speed of the strip in the process section, combined with the length of the air cushion furnace, and the actual production experience, the specific needs of the gradient control tension change, the proportion Kp value in the PID tension control is calculated.

[0081] In this example, the tension roller is a device that provides power through rotation, which can stretch or compress objects to generate tension. The motor of the tension roller converts rotational energy into mechanical energy and delivers this energy to the material passing through the tension roller (aluminum strip) through a large rubber or metal wheel (normally a rubber roller is used in aluminum processing).

[0082] The tension roller device and control mechanism include

[0083] On-site setup: tension roller (rubber roller) + reducer + AC motor

[0084] ① Tension roller (rubber roller): load the strip to generate tension. When the material passes through the tension roller, it needs to overcome the resistance exerted by the tension roller, thus generating tension.

[0085] ② Reducer: reduces motor speed while increasing output torque;

[0086] ③ AC motor: rotates to drive the roller;

[0087] Control mechanism: PLC controller + transmission device

[0088] PLC controller: set various parameters, such as sending commands to the transmission device for controlling the logic, speed, torque, etc. of the motor rotation

[0089] Transmission device: controls the AC motor by changing the frequency of the motor's working power supply;

[0090] The tension meter consists of two tension detection sensors and two tension controller modules

[0091] Tension detection sensor: on the roller seat of the operating side and the transmission side, detects the tension value of the roller seat along the direction of the strip;

[0092] Tension controller: used to receive and convert the tension value detected by the tension detection sensor, while having the function of sending the tension value to the PLC controller and receiving the tension set value from the PLC controller.

[0093] In this example, the motor transmission device controls the rotation of the AC motor, and the motor transmission device uses the S120 or G120 series from Siemens.

[0094] The PLC controller uses the 400 series from Siemens or similar, which is used for logic calculation and control of the operation of the device, and the initial value of the device operation constant can be set in the PLC.

[0095] A tension meter is used to detect the tension value of the strip between the air cushion furnaces.

[0096] The air cushion furnace is used for heating, holding, cooling the strip, and suspending the strip.

[0097] The stitch hole detection device is used to detect the actual position of the stitch hole (to determine whether the current position is the stitch hole).

[0098] The deviation correction roller is used to control the movement along the equipment operation side or the transmission side when the strip in the air cushion furnace deviates, so as to ensure that the strip is within the center line range.

Claims

1. A method for improving the stable operation of a seam at a strip in a gas cushion furnace, the strip being formed by joining a front coil of strip and a rear coil of strip at the seam, the strip being fed to the gas cushion furnace for annealing treatment on a roller table with a set of tension rolls, the front coil of strip and the rear coil of strip having different tension values before being fed to the gas cushion furnace, characterized in that: The method comprises a seam detection position arranged at a roller table in front of an air cushion furnace entrance, and further comprises a seam detector of the seam detection position, a PLC controller connected with a tension roller set, when the seam of the strip passes through the seam detection position, the PLC controller acquires the tension values of the front coil strip and the rear coil strip through the tension detection sensors at the tension roller set, and before the seam enters the air cushion furnace, the motor working condition of the tension roller set is adjusted, the tension output of the tension roller is adjusted in a gradient control mode, and the tension value of the front coil strip is gradually adjusted, so that the tension value of the front coil strip is consistent with the tension of the rear coil strip. ​ 2. The method of claim 1, wherein the method further comprises: The tension roller set comprises a first tension roller set located in front of the air cushion furnace entrance B point, and a second tension roller set located behind the air cushion furnace exit C point; ​ The first tension roller set and the second tension roller set are used for adjusting the tension of the strip at the air cushion furnace, and both of them use an alternating current motor as a power source; The first tension roller set and the second tension roller set both comprise a tension roller, a speed reducer and an alternating current motor, the alternating current motor is used for driving the tension roller to rotate, the speed reducer adjusts the output torque of the alternating current motor by adjusting the rotating speed of the alternating current motor, and the tension roller applies tension to the strip by applying resistance to the strip when the strip passes through.

3. The method of claim 2, wherein the method further comprises: providing a plurality of gas jets to the gap between the first and second rollers. The first tension roller set comprises a No.1-1 tension roller and a No.1-2 tension roller arranged in sequence in the strip conveying direction, the second tension roller set comprises a No.2-1 tension roller, a No.2-2 tension roller, a No.2-3 tension roller and a No.2-4 tension roller arranged in sequence in the strip conveying direction, and the seam reaches a stable state when running to a D point of the No.2-2 tension roller after the annealing treatment of the seam through the air cushion furnace. The seam detector is arranged at an A point of the No.1-1 tension roller, a tension meter is arranged at the No.1-2 tension roller, and the tension meter comprises a tension controller and a plurality of tension detection sensors; The tension detection sensors are arranged on the roller seats on the operating side and the transmission side of the No.1-2 tension roller, and are used for detecting the tension value of the roller seat along the strip direction; The tension controller is connected with the tension detection sensors, the PLC controller and the alternating current motor of the tension roller set, is used for receiving and converting the tension value detected by the tension detection sensors, and sends the converted tension value to the PLC controller, and can receive the tension given value of the PLC controller, and controls the alternating current motor of the No.1-2 tension roller according to the tension given value to adjust the tension output of the tension roller.

4. The method of claim 3, wherein the method further comprises: The PLC controller calculates the tension given value of the No.1-2 tension roller by using a PID control method, and the calculation method of a proportional coefficient Kp value of the PID control method comprises the following steps: Step S1, when the PLC controller detects the position of the seam at the A point, at this time, the time t1 required for the seam to run to the B point of the air cushion furnace entrance is set as L1 / V1, the time t2 required for the seam to pass through the entire air cushion furnace from the air cushion furnace entrance B point to the air cushion furnace exit C point is L2 / V2, and the time t3 required for the seam to reach the stable position D point from the air cushion furnace is L3 / V2. Step S2, the PLC controller detects the strip tension before and after the seam through the tension detection sensor; the detected front coiled strip tension value is N1, and the rear coiled strip tension value is N2; then the formula is used to calculate, and N1=W1*T1*n1, N2=W2*T2*n2, Kp=(N1-N2) / (t1+t2+t3), Kp=(W1*T1*n1-W2*T2*n2) / (t1+t2+t3) are obtained. Step S3, when Kp>0, the rotation condition of the motor is controlled through the PLC controller, and then the tension is controlled to decrease from N1 to N2; when Kp=0, the tension is kept unchanged; when Kp<0, the rotation condition of the motor is controlled through the PLC controller, and then the tension is controlled to increase from N1 to N2. In the above formulae: L1 is the position of the seam detection position away from the air cushion furnace inlet, and the unit is m; L2 is the length of the air cushion furnace, and the unit is m; L3 is the position of the air cushion furnace outlet to the safe area, and the unit is m; V1 is the process speed of the front coiled, and the unit is m / min; V2 is the process speed of the rear coiled, and the unit is m / min; n1 is the process unit tension value of the front coiled, and the unit is N; n2 is the process unit tension value of the rear coiled, and the unit is N; W1 is the width of the front coiled strip, and the unit is mm; W2 is the width of the rear coiled strip, and the unit is mm; T1 is the thickness of the front coiled strip, and the unit is mm; T2 is the thickness of the rear coiled strip, and the unit is mm; Kp is the proportion value in the PID tension control of the air cushion furnace tension control. The air cushion furnace outlet C point and the 2-1 number tension roller are provided with a deviation correction roller for controlling the attitude of the strip in the air cushion furnace; when the strip in the air cushion furnace deviates, the deviation correction roller moves to the equipment operation side or the transmission side to ensure that the strip runs in the center line range of the air cushion furnace. The strip sent into the air cushion furnace for annealing treatment has a superimposed seam structure of the front coiled strip and the rear coiled strip, and the seam thickness is different from the thickness of the strip before and after the seam; The seam detector includes a detection surface parallel to the surface of the strip formed by at least two laser measuring devices, and the arrangement direction of the two laser measuring devices is perpendicular to the running direction of the strip; the PLC detects the distance between the detection surface of the seam detector and the surface of the strip through the two laser measuring devices. The method for detecting the seam by the PLC through the seam detector is that when the strip passes through the detection area of the seam detector, if the distance between the detection surface of the seam detector and the surface of the strip is unchanged and the situation lasts for a time longer than threshold A, it is determined that no seam passes through the seam detector; if the distance between the detection surface of the seam detector and the surface of the strip changes suddenly and the situation lasts for a time longer than threshold B, it is determined that the seam passes through the seam detector, and threshold A is greater than threshold B.

5. The method of claim 3, wherein the method further comprises: providing a plurality of gas jets to the gap between the first and second rollers. ​ 6. The method of claim 2, wherein the method further comprises: providing a gas curtain between the first and second gas curtains. ​ ​ 7. The method of claim 2, wherein: the method further comprises: providing a plurality of gas jets; and positioning the plurality of gas jets to direct a flow of gas at the gap between the first and second strips. 5 ​

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