CN113751509A - Control method for pressing time of tail pressing roller of continuous rolling mill - Google Patents
Control method for pressing time of tail pressing roller of continuous rolling mill Download PDFInfo
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- CN113751509A CN113751509A CN202110974012.4A CN202110974012A CN113751509A CN 113751509 A CN113751509 A CN 113751509A CN 202110974012 A CN202110974012 A CN 202110974012A CN 113751509 A CN113751509 A CN 113751509A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
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Abstract
A control method for the pressing time of a tail pressing roller of a tandem mill belongs to the technical field of automatic control of aluminum processing. The invention controls the action of the tail pressing roller by establishing the mathematical relationship between the time of the tail of the coiled material leaving the finishing mill group and the action time of the tail pressing roller so as to achieve the aims of improving the yield and reducing the labor. For a rolling control system with a PLC, the invention can input a time delay formula into the PLC, and the system carries out calculation and automatic control to realize accurate control of the tail roller pressing and leaning time. The method has obvious adaptability to the diversity of coiled material orders, can greatly improve the yield of the coiled materials, and reduces the waste of manpower and material resources.
Description
Technical Field
The invention relates to the technical field of rolling, in particular to a method for controlling the pressing time of a tail pressing roller of a 1+4 aluminothermic continuous rolling mill.
Background
The aluminum coiled material is usually rolled and produced by adopting a 1+4 hot continuous rolling mode, wherein the 1 represents a roughing mill, and a strip blank after hot rolling by the roughing mill is called an intermediate blank; "4" represents a continuous rolling mill having 4 stands, through which continuous hot finish rolling the intermediate slab into an aluminum strip and finally forming a coil on a coiler. In the continuous hot finish rolling process, the speed difference exists between the coiling machine and the continuous rolling mill, so that coiling tension is formed, and the coiling tension can reach 67T/MPa at most. When the tail of the strip leaves the last rolling mill, a tail cast will occur: under the effect of coiling tension, the tail of the coiled material can be rebounded violently, severe scratch can be generated between layers of the coiled material, and the tail of the rebounded coiled material can also cause collision injury to surrounding people and equipment. In order to ensure the product quality and the safety of personnel and equipment, the coiled material tail throwing prevention is necessary.
At present, a tail-throwing prevention measure which is commonly adopted is that a tail-pressing roller is adopted to press a coiled material, the measure needs to send a pressing signal to the tail-pressing roller arranged above a coiling machine at a proper time, so that the tail-pressing roller can press the tail part of the coiled material at a proper time after walking for a period of time, the tail part of a strip material is ensured to be tightly attached to a coiling surface, and the coiled material is ensured not to be loosened. If the pressing time of the tail pressing roller is too long, the length of the coiled material contacted with the tail pressing roller is long, the coiled material is cut off due to poor surface quality, and the yield is reduced; if the time that the tail roller pressed is too late, firstly the tail can be thrown, secondly the outer lane of coiled material can't directly get into the packaging process because of the pine layer easily, must amputate the coiled material on outside pine layer, and this has reduced the lumber recovery equally, has still caused the waste on the manpower and materials.
For an aluminothermic continuous rolling production line, the distances between four rolling mills of a continuous rolling mill are 5-6 meters, but because the rolling speed is very high, the rolling speed of the last rolling mill (the fourth rolling mill) is usually 3-4 meters/second, a tail pressing roller needs to move to one side of a coiled material after the tail of a strip leaves the third rolling mill and before the tail of the strip enters the fourth rolling mill, the reaction time given to an operator is less than 2 seconds, and the operator needs to estimate the movement time advance required by the tail pressing roller to abut against the coiled material according to the diameter of the current coiled material, which is a challenge for the operator, so that the manual control is difficult to stably and accurately control the timing of the tail pressing roller.
For rolling of single-variety aluminum coils, the pressing time of the tail pressing roller can be controlled by a sensor delay method, but orders of coils have diversity, and the pressing time of the tail pressing roller is difficult to estimate manually due to the difference of the blanking amount, the width, the thickness and the coiling speed of an intermediate billet, so that a control method based on a mathematical model needs to be established to guide the pressing time of the tail pressing roller in real time.
Disclosure of Invention
In order to overcome the defects in the background art, the invention discloses a control method for the pressing time of a tail pressing roller of a tandem mill, which aims to: a mathematical model-based control method is established to guide the pressing timing of the tail pressing roller in real time.
In order to achieve the purpose, the invention adopts the following technical scheme:
a control method for the pressing and leaning time of a tail pressing roller of a continuous rolling mill is provided, the continuous rolling mill is provided with N rolling mills, and is characterized in that: a sensor is arranged on the first rolling mill, and when the tail of the strip breaks away from the roll gap of the first rolling mill, the sensor sends a signal to the tail pressing roll; delaying for t seconds after the tail pressing roller obtains the signal, and then starting pressing action; the calculation formula of the delay time t is as follows:
in the formula, T1: roll gap size of the first stand rolling mill; t2: roll gap size of the second stand rolling mill; tn-2: the roll gap size of the N-2 th rolling mill; tn-1: the roll gap size of the N-1 th rolling mill; tn: the roll gap size of the Nth rolling mill; l1: the distance between the first stand rolling mill and the second stand rolling mill; l2: the distance between the second rolling mill and the third rolling mill; ln-2: the distance between the (N-2) th rolling mill and the (N-1) th rolling mill; ln-1: the distance between the (N-1) th rolling mill and the (N) th rolling mill; and Vn: the rolling speed of the Nth rolling mill; s: the movement speed of the tail pressing roller; r: the radius of the winding mandrel; l: the length of the intermediate blank; t0: the thickness of the intermediate blank; h: the vertical distance between the tail pressing roller and the axis of the reeling mandrel.
The technical scheme is further improved, and the sensor is a rolling force sensor.
Further improving the technical scheme, the continuous rolling mill is provided with four rolling mills, wherein the calculation formula of the delay time t is as follows:
in the formula, T1: roll gap size of the first stand rolling mill; t2: roll gap size of the second stand rolling mill; t3: roll gap size of a third rolling mill; t4: the roll gap size of the fourth rolling mill; l1: the distance between the first stand rolling mill and the second stand rolling mill; l2: the distance between the second rolling mill and the third rolling mill; l3: the distance between the third rolling mill and the fourth rolling mill; v4: rolling speed of the fourth rolling mill.
The technical scheme is further improved, wherein N is more than or equal to N, 3 and less than or equal to 7.
The technical scheme is further improved, and the control method is realized through a PLC (programmable logic controller).
Further improving the technical scheme, wherein the calculation formula of the delay time t is as follows:
in the formula, K is a correction parameter of the delay time, and K is more than 0.1s and less than 1 s.
Due to the adoption of the technical scheme, compared with the background technology, the invention has the following beneficial effects:
the invention can effectively prevent the phenomenon of tail throwing on the premise of ensuring the high yield of the coiled material, and the reliability is kept above 98 percent.
For a rolling control system with a PLC, the invention can input a time delay formula into the PLC, and the system carries out calculation and automatic control to realize accurate control of the tail roller pressing and leaning time. The method has obvious adaptability to the diversity of coiled material orders, can greatly improve the yield of the coiled materials, reduces the waste of manpower and material resources, and has huge economic value.
Drawings
FIG. 1 is a schematic structural diagram of the present invention.
In the figure: 1. a first stand rolling mill; 2. a second stand rolling mill; 3. a third rolling mill; 4. a fourth rolling mill; 5. a tail pressing roller; 6. coiling a mandrel; 7. a strip of material.
Detailed Description
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention.
Example 1:
a control method of the pressing time of a tail pressing roller 5 of a tandem mill is used for rolling an aluminum coiled material. As shown in FIG. 1, the aluminum coil is usually produced by 1+4 hot continuous rolling, and after rough rolling, the width B of the intermediate blank is 1200mm, the thickness T0 is 35mm, and the length L is 57 m. And a four-tandem mill is adopted for finish rolling, and the final rolling thickness of the aluminum coiled material is 2 mm. In the four-stand rolling mill, the distance between the first stand rolling mill 1 and the second stand rolling mill 2 is L1, the distance between the second stand rolling mill 2 and the third stand rolling mill 3 is L2, the distance between the third stand rolling mill 3 and the fourth stand rolling mill 4 is L3, and L1 ═ L2 ═ L3 ═ 5.5 m. The roll gap size T1 of the first stand rolling mill 1 was 17.6mm, the roll gap size T2 of the second stand rolling mill 2 was 8.2mm, the roll gap size T3 of the third stand rolling mill 3 was 3.5mm, the roll gap size T4 of the fourth stand rolling mill 4 was 2mm, and the rolling speed V4 of the fourth stand rolling mill 4 was 4 m/s.
In order to collect signals conveniently, a rolling force sensor is arranged on the first rolling mill 1 of the four-tandem mill, and when the tail of the strip 7 is separated from the roll gap of the first rolling mill 1, the rolling force sensor loaded on the working roll can obtain obvious signals.
According to the principle that the rolling volume is not changed, the volume of the intermediate billet is equal to that of the finally obtained aluminum coil. Because the change of the band width is not large in the rolling process, the rolling process can be regarded as equal-width rolling, and the rolling gap of the coiled material is not counted, the volume V0 of the intermediate billet exists,
V0＝L*B*T0＝πR2*B-πr2*B
in the formula, R: the radius of the coil; r: the radius of the winding mandrel 6.
As can be inferred from the above equation, when the intermediate slab is completely rolled into a coil, the diameter of the coil
Then the time t1 required for the tail roller 5 to press against the web is: t1 ═ H-R)/S, where S is the running speed of the tail nip, H: the vertical distance between the tail pressing roller 5 and the axis of the winding mandrel 6. In this embodiment, the moving speed S of the tail roller is 0.1m/S, the vertical distance H between the tail roller 5 and the axis of the winding mandrel 6 is 1m, and the radius r of the winding mandrel 6 is 0.2 m.
Similarly, when the tail of the strip 7 is separated from the roll gap of the first stand rolling mill 1, the section of the strip 7 between the first stand rolling mill 1 and the fourth stand rolling mill 4 flows out at the rolling thickness and the rolling speed of the fourth stand rolling mill 4 regardless of the thickness and the length of the strip, and then the time t2 from the separation of the tail of the strip 7 from the roll gap of the first stand rolling mill 1 to the entrance of the tail of the strip 7 into the roll gap of the fourth stand rolling mill 4 is the period of time t2
In order to achieve precise control of the timing of the tail roller 5, the tail roller 5 needs to be moved early and pressed against the coil before the tail of the strip 7 comes out of the gap of the fourth rolling mill 4. Therefore, the optimum pressing timing of the pinch roll 5 is set to t seconds after the rolling force sensor sends a signal to the pinch roll 5, and the pressing operation is started after t2-t 1. Substituting t1 and t2 obtains the formula of delay time:
the values are substituted, and the delay time t is 20.14-8.76-11.38 s.
That is, after the tail roller 5 receives the signal, the pressing action is started after a delay of 11.38 seconds, and the tail of the strip 7 is pressed against the strip just after the tail is released from the gap of the third rolling mill 3 and before the tail is released from the gap of the fourth rolling mill 4. For increasing the security and reliability, the delay time t can be rounded to 12 seconds by a rounding-up function. And a delay time correction parameter K can be added into the formula to perform adaptive adjustment according to the actual operation condition.
For a rolling control system with a PLC (programmable logic controller), a time delay formula can be input into the PLC, and the system performs calculation and automatic control to realize accurate control of the pressing time of the tail pressing roller 5. The method has obvious adaptability to the diversity of the order of the coiled materials, and can greatly improve the yield of the coiled materials.
Example 2:
unlike example 1, the intermediate slab after rough rolling had a width B of 1340mm, a thickness T0 of 50mm and a length L of 45 m. And a four-tandem mill is adopted for finish rolling, and the final rolling thickness of the aluminum coiled material is 5 mm. The roll gap size T1 of the first stand rolling mill 1 was 30.54mm, the roll gap size T2 of the second stand rolling mill 2 was 16.14mm, the roll gap size T3 of the third stand rolling mill 3 was 8.99mm, the roll gap size T4 of the fourth stand rolling mill 4 was 5mm, and the rolling speed V4 of the fourth stand rolling mill 4 was 3 m/s.
Substituting the formula of the delay time:
the delay time t is 20.41-8.53-11.88 s.
In practice it has been found that each time the tail rolls 5 are pressed against the coil, the distance between the tail of the strip 7 and the roll gap of the fourth rolling mill 4 is about 3m, i.e. the pressing time of the tail rolls 5 is advanced by about 1 second, which increases the cut-off by about 3m and reduces the yield of the strip. At this time, a correction formula may be used:
where K is a correction parameter of the delay time, and K is 0.7s, then the delay time t is 11.18 seconds. Therefore, on the basis of ensuring the pressing reliability, the cutting-off amount of the strip tail of about 2.1 meters is reduced, and the yield of the strip is improved.
The details of which are not described in the prior art. Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (6)
1. A control method for the pressing and leaning time of a tail pressing roller of a continuous rolling mill is provided, the continuous rolling mill is provided with N rolling mills, and is characterized in that: a sensor is arranged on the first rolling mill, and when the tail of the strip breaks away from the roll gap of the first rolling mill, the sensor sends a signal to the tail pressing roll; delaying for t seconds after the tail pressing roller obtains the signal, and then starting pressing action; the calculation formula of the delay time t is as follows:
in the formula, T1: roll gap size of the first stand rolling mill; t2: roll gap size of the second stand rolling mill; tn-2: the roll gap size of the N-2 th rolling mill; tn-1: the roll gap size of the N-1 th rolling mill; tn: the roll gap size of the Nth rolling mill; l1: the distance between the first stand rolling mill and the second stand rolling mill; l2: the distance between the second rolling mill and the third rolling mill; ln-2: the distance between the (N-2) th rolling mill and the (N-1) th rolling mill; ln-1: the distance between the (N-1) th rolling mill and the (N) th rolling mill; and Vn: the rolling speed of the Nth rolling mill; s: the movement speed of the tail pressing roller; r: the radius of the winding mandrel; l: the length of the intermediate blank; t0: the thickness of the intermediate blank; h: the vertical distance between the tail pressing roller and the axis of the reeling mandrel.
2. The method for controlling the pressing timing of the pinch rolls of the tandem mill as claimed in claim 1, wherein:
the sensor is a rolling force sensor.
3. The method for controlling the pressing timing of the pinch rolls of the tandem mill as claimed in claim 1, wherein:
the continuous rolling mill is provided with four rolling mills, wherein the calculation formula of the delay time t is as follows:
in the formula, T1: roll gap size of the first stand rolling mill; t2: roll gap size of the second stand rolling mill; t3: roll gap size of a third rolling mill; t4: the roll gap size of the fourth rolling mill; l1: the distance between the first stand rolling mill and the second stand rolling mill; l2: the distance between the second rolling mill and the third rolling mill; l3: the distance between the third rolling mill and the fourth rolling mill; v4: rolling speed of the fourth rolling mill.
4. The method for controlling the pressing timing of the pinch rolls of the tandem mill as claimed in claim 1, wherein:
n is more than or equal to 3 and less than or equal to 7.
5. The method for controlling the pressing timing of the pinch rolls of the tandem mill as claimed in claim 1, wherein:
the control method is realized by a PLC controller.
6. The method for controlling the pressing timing of the pinch rolls of the tandem mill as claimed in claim 1, wherein:
the calculation formula of the delay time t is as follows:
in the formula, K is a correction parameter of the delay time, and K is more than 0.1s and less than 1 s.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110974012.4A CN113751509A (en) | 2021-08-24 | 2021-08-24 | Control method for pressing time of tail pressing roller of continuous rolling mill |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110974012.4A CN113751509A (en) | 2021-08-24 | 2021-08-24 | Control method for pressing time of tail pressing roller of continuous rolling mill |
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| CN113751509A true CN113751509A (en) | 2021-12-07 |
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| CN202110974012.4A Withdrawn CN113751509A (en) | 2021-08-24 | 2021-08-24 | Control method for pressing time of tail pressing roller of continuous rolling mill |
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Application publication date: 20211207 |