A method for controlling the speed of a weld seam rolling mill of a pickling and rolling combined unit

Abstract

The application discloses a kind of weld seam over-rolling mill speed control methods of pickling rolling mill combined unit, the method uses two-step speed reduction, first step speed reduction is executed when weld seam to rolling mill entrance, second step speed reduction is executed when weld seam is in the rolling mill rack transition to 3 rack;The rolling parameters of the weld seam in the rack speed reduction under the conventional roll mode of the rolling mill, the dynamic variable-gauge roll mode of the rolling mill, the conventional roll mode of the inspection sampling and the dynamic variable-gauge roll mode of the inspection sampling are optimized in the method, the welding seam over-rolling mill speed can be significantly improved, and the production efficiency and capacity are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel rolling process control, in particular to a welding seam over-rolling mill speed control method of a pickling rolling mill combined unit. BACKGROUND

[0002] The production process of a five-stand six-roll continuous cold rolling mill unit is as follows: a hot-rolled raw material coil with two ends welded is continuously rolled through multiple stands to form a cold-rolled steel coil meeting the size and performance requirements. At present, the method for the continuous cold rolling mill unit to pass through the welding seam at low speed in the industry all adopts the method of reducing the welding seam to the shearing speed at the entrance of the rolling mill, maintaining a low constant speed through the rolling mill, and shearing the coil at the drum shear. However, the welding seam maintains a low constant speed through the rolling mill for a long time, which restricts the play of the continuous rolling mill unit capacity and affects the rolling mill production efficiency.

[0003] Therefore, it is necessary to develop a new method for improving the welding seam over-rolling mill speed of the five-stand six-roll continuous cold rolling mill unit, which can reduce the running time, improve the rolling mill production efficiency, and improve the capacity. SUMMARY

[0004] The purpose of the present application is to provide a welding seam over-rolling mill speed control method of a pickling rolling mill combined unit, and more specifically, to provide an innovative rolling mill welding seam speed operation mechanism of a cold rolling pickling rolling mill combined production unit, so as to improve the welding seam over-rolling mill speed, improve the production efficiency and capacity.

[0005] To this end, the present application adopts the following technical solutions:

[0006] The present application provides a welding seam over-rolling mill speed control method of a pickling rolling mill combined unit, comprising the following steps:

[0007] Two-step speed reduction is adopted, the first step speed reduction is performed when the welding seam enters the entrance of the rolling mill, and the second step speed reduction is performed when the welding seam transitions to the third stand in the rolling mill stand.

[0008] Further preferably, the following steps are included:

[0009] The first step speed reduction is to reduce to V1 before the welding seam enters the rolling mill, and the second step speed reduction is to complete the speed reduction to the set speed V2 at the rolling mill exit shearing when the welding seam is rolled to the third stand in the stand, V2 < V1.

[0010] Further preferably, the above V1 is the maximum shearing speed V max of the rolling mill exit drum shear, and the V max is 250 m / min.

[0011] In the embodiments of the present application, the working modes of the method of the present application include a mill conventional strip dividing mode, a mill dynamic gauge changing strip dividing mode, an inspection sampling conventional strip dividing mode and an inspection sampling dynamic gauge changing strip dividing mode.

[0012] Further preferably, the specific steps in the mill conventional strip dividing mode are as follows:

[0013] First step: the strip before and after the weld has the same gauge, the weld is first reduced in speed to the maximum shearing speed of the mill exit roller shears, 250 m / min;

[0014] Second step: the weld is further reduced to the set shearing speed of the mill exit, 100-200 m / min, when it reaches the third stand, and the speed is completed when it reaches the fifth stand, the head and tail of the weld are rolled at a low speed between the third and fifth stands, so as to ensure that the plate shape and the weld rolling quality are controlled.

[0015] Further preferably, the specific steps in the mill dynamic gauge changing strip dividing mode are as follows:

[0016] The strip before and after the weld has different gauges, and the dynamic gauge changing is performed for different process steel grades; the weld is first reduced in speed to the maximum shearing speed of the mill exit roller shears, 250 m / min;

[0017] The speed is completed when the weld reaches the third stand, and the speed of the mill exit shears is set to 130 m / min, which can prevent the weld at the edge punching part from being opened by the mill;

[0018] The speed is completed when the weld reaches the third stand, and the speed of the mill exit shears is set to 130 m / min, which can prevent the weld at the edge punching part from being opened by the mill;

[0019] Preferably, when the edge is punched by the disc shears, the weld is rolled at a low speed, the speed is completed when the weld reaches the third stand, and the speed of the mill exit shears is set to 130 m / min, which can prevent the weld at the edge punching part from being opened by the mill;

[0020] When the edge is not punched by the disc shears, the weld is rolled at a high speed, the speed is completed when the weld reaches the third stand, and the speed of the mill exit shears is set to 150 m / min.

[0021] Further preferably, the specific steps in the inspection sampling conventional strip dividing mode are as follows:

[0022] First step: the weld is reduced in speed to the set speed of the exit shears in the conventional shearing mode, 200 m / min, at the mill entrance;

[0023] Second step: the weld is further reduced to the set speed of the exit shears, 100 m / min, when it reaches the third stand, and the head and tail of the weld are rolled at a low speed between the third and fifth stands, so as to ensure that the plate shape and the weld rolling quality are controlled, and the maximum speed of the inspection table for the 10-meter head / tail is 100 m / min.

[0024] Further preferably, the specific steps in the inspection sampling dynamic gauge changing strip dividing mode are as follows:

[0025] First step: the weld to the mill entrance speed to the conventional shear dynamic variable gauge mode speed 150 m / min or 130 m / min;

[0026] Second step: the weld to 3 machine frame, and then to the set speed 100 m / min at the exit shear, the weld head and tail in 3 to five 5 machine frame at low speed rolling, to ensure the product shape and weld rolling quality controlled, and meet the strip head / tail 10 meters on the inspection table maximum speed 100 m / min.

[0027] The method theory and technical explanation:

[0028] (1) The implementation method is to optimize and improve the automatic speed reduction function of the shear when the strip is cut into a roll by combining the production line automation technology, and to innovate the weld speed operation mechanism in the mill. The automatic speed reduction function of the weld into the mill is divided into two steps. The first step is executed when the weld enters the mill, and the second step is executed when the weld transitions to three machine frames in the mill, to ensure that the weld is less affected by the alternating load of the mill at low speed, and to ensure that the weld has good shape and does not cause quality defects such as poor inner circle shape caused by excessive inner circle shape due to excessive roll speed.

[0029] (2) The 1-5 machine frames of the cold continuous rolling mill correspond to the rolling parameters such as rolling force, tension, and bending roll. To ensure the distribution of deformation, 1 and 2 machine frames bear a larger deformation, and the shape and thickness deviation of the strip head and tail will also affect the smooth progress of the rolling process. The 4 and 5 machine frames are close to the mill exit, and the speed reduction time is too short, and the 5 machine frame is responsible for the strip shape control, finished product thickness deviation control, and finished product roughness control, etc. Therefore, the 3 machine frame is selected as the execution point of the second step.

[0030] (3) Optimize the rolling parameters of the weld speed reduction in the machine frame. By comparing the deformation, rolling force, tension, and other rolling parameters of each machine frame of the mill, the deformation of the 3 machine frame is appropriately adjusted to the 1 and 2 machine frames, and the rolling speed adjustment is performed when the weld reaches the 3 machine frame. Under the relatively small deformation, the risk of strip breakage can be effectively reduced. The optimized mill speed reduction shape control function pre-adjusts the additional tension of each machine frame and the bending of each machine frame work roll, effectively eliminating the shape impact of adjusting the speed at the 3 machine frame.

[0031] (4) The maximum sampling speed of the on-line inspection table of the 1550 pickling and rolling mill unit of Zhanjiang Iron and Steel is 100 m / min (mill outlet speed), and the sampling strip steel is 10 meters per block. The welding seam into the mill speed is reduced to 100 m / min from 250 m / min, and the large speed reduction slope will cause large tension difference and rolling force fluctuation, which is easy to cause strip breakage and other risks. Therefore, in the conventional division mode of inspection sampling, the second step operation is performed when the welding seam is reduced to the conventional shearing mode outlet set speed to the third rack.

[0032] (5) The hot-rolled coil before and after the dynamic variable gauge welding seam is of different steel grades, different widths and different thicknesses, which causes the produced cold-rolled coil to also be of different specifications. Therefore, when changing from one specification to another, there is inevitably a wedge-shaped transition zone, and the roll gap, roll speed, tension, bending roll and other set values of each rack gradually change with the movement of the wedge-shaped transition zone. Therefore, the welding seam needs to run at a lower speed in the mill to complete the dynamic variable gauge, and when the welding seam is edge-punched by the disc shear, the roll gap, roll speed, tension and bending roll fluctuate greatly. Therefore, the speed needs to run in a lower range, and bending roll compensation and other measures are taken to prevent the occurrence of opening.

[0033] Compared with the prior art, the beneficial effects of the present application are:

[0034] By adopting the welding seam over-mill speed control method of the pickling and rolling mill combined unit of the present application, the welding seam speed operation mechanism in the mill is improved. The present application method optimizes the welding seam speed operation mechanism in the mill under the automatic rolling operation of the intelligent manufacturing and production line automation technology in the conventional division and inspection sampling division modes, significantly improves the welding seam over-mill speed, thereby shortens the production time and improves the production capacity of the pickling and rolling mill combined unit. DETAILED DESCRIPTION

[0035] The specific embodiments of the technical solutions of the present application are further described below. These embodiments are for the detailed description of the technical solutions of the present application, and are not intended to limit the technical solutions of the present application. Based on the embodiments in the present description, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present description.

[0036] Embodiment 1

[0037] This embodiment takes the cold rolling 1550 pickling and rolling mill unit of Zhanjiang Iron and Steel as an example.

[0038] The welding seam over-mill speed control method of the above-mentioned cold rolling 1550 pickling and rolling mill unit is:

[0039] The first step of reducing speed is performed when the weld seam enters the rolling mill, the second step of reducing speed is performed when the weld seam is transitioned to the third stand in the rolling mill, and then the weld seam is kept at a low speed to pass through the rolling mill, and the coil is cut at the roll shear.

[0040] In the conventional coil dividing mode of the rolling mill, the weld seam is first reduced to the maximum shearing speed of 250 m / min at the exit roll shear of the rolling mill, and then reduced to the set shearing speed of 200 m / min at the exit shear of the rolling mill, and then kept at a constant speed to pass through the rolling mill, and the coil is cut at the roll shear.

[0041] In the dynamic variable gauge coil dividing mode of the rolling mill, the weld seam is first reduced to the maximum shearing speed of 250 m / min at the exit roll shear of the rolling mill, and then reduced to the set shearing speed of 130 m / min at the exit shear of the rolling mill, and then kept at a constant speed to pass through the rolling mill, and the coil is cut at the roll shear.

[0042] In the inspection sampling conventional coil dividing mode, the weld seam is first reduced to the set speed of 200 m / min at the exit shear of the conventional shearing mode, and then reduced to the set speed of 100 m / min at the exit shear, and then kept at a constant speed to pass through the rolling mill, and the coil is cut at the roll shear.

[0043] In the inspection sampling dynamic variable gauge coil dividing mode, the weld seam is first reduced to the set speed of 150 m / min at the exit shear of the conventional shearing dynamic variable gauge mode, and then reduced to the set speed of 100 m / min at the exit shear, and then kept at a constant speed to pass through the rolling mill, and the coil is cut at the roll shear.

[0044] The weld seam passing speed control method of the present application significantly improves the weld seam passing speed of the rolling mill, reduces the time of various mode shearing and dividing, and improves the production capacity, and the results are as follows:

[0045] 1) Under the assistance of the present method, the production capacity of Zhanjiang 1550 pickling and rolling mill group in 2021 is increased by about 5.58 million tons compared with that in 2020 under the condition of basically consistent material gauge;

[0046] 2) After the implementation of the present method, the hourly production of the mill is increased from 205.803 t / h to 219.445 t / h;

[0047] 3) Taking the conventional mode shearing and dividing as an example, the average production time of each coil can be shortened by 10 seconds, and according to the monthly average daily material condition in 2021, the average AGC mode is 180 coils per day, and the production efficiency can be improved by 30 minutes per day, and the production capacity can be improved by 30*29 (30 days / month) / 60 = 14.5 hours per month. The hourly production is 200 tons / hour, the production capacity can be improved by 2900 tons per month, and the production capacity can be improved by 3.48 million tons per year.

[0048] 4) Taking the dynamic variable specification shearing and rewinding mode as an example, the average production time per roll can be shortened by 6 seconds. Based on the average daily material conditions in 2021, with an average of 50 rolls produced per day in FGC mode, the production efficiency can be increased by 5 minutes per day, and the monthly capacity can be increased by 5*29(30 days / month) / 60=2.4 hours. With an hourly output of 200 tons / hour, the monthly capacity efficiency can be increased by 480 tons, and the annual capacity can be increased by 5760 tons.

[0049] 5) Taking the conventional shearing and rewinding mode of inspection and sampling as an example, the average production time per roll can be shortened by 20 seconds. Based on the average daily material conditions in 2021, this mode has an average of 30 shearing and sampling times per day, which can save 10 minutes. The hourly output is 200 tons / hour, and the monthly capacity can be increased by 10*29(30 days / month) / 60=4.8 hours. The time saved can increase the monthly capacity efficiency by 960 tons, and the annual capacity can be increased by about 11,500 tons.

[0050] 6) Taking the dynamic specification change mode of inspection and sampling as an example, the average production time per roll can be shortened by 10 seconds. Based on the average daily material conditions in 2021, the average number of shearing and sampling times per day under this mode is 20, which can save 3.3 minutes. The hourly output is 200 tons / hour, and the monthly production capacity can be increased by 3.3*29(30 days / month) / 60=1.6 hours. The time saved can increase the production capacity efficiency by 320 tons per month, and the annual production capacity can be increased by about 3,800 tons.

[0051] This invention uses the automatic speed reduction function of the rolling mill during shearing and coiling in a five-stand, six-roll cold continuous rolling mill as the optimized control variable. At the same time, it optimizes and controls the rolling process parameters such as rolling force, tension, and bending rolls of each stand. It also takes into account the strip shape and weld rolling quality control issues. While achieving the optimal exit strip shape, it innovates the weld speed operation mechanism in the rolling mill, increases the weld speed through the rolling mill, and shortens the weld running time in the rolling mill as the control objective, thereby shortening the overall production time of each coil.

[0052] This invention develops an innovative speed operation mechanism for weld seams within a combined cold rolling and pickling mill unit, increasing the speed at which weld seams pass through the mill and thus boosting production capacity. This improves the unit's actual production efficiency and brings considerable economic benefits to the company. The application of this invention at Baosteel Zhanjiang Iron & Steel Cold Rolling Plant demonstrates its feasibility and potential for further promotion within the company or to other similar cold rolling mill units nationwide, indicating a broad prospect for its application.

[0053] Although embodiments of the present description have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present description, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method of controlling the speed of a weld roll in a pickling and rolling tandem unit, characterized by, The method comprises the following steps: adopting two-step speed reduction, the first step is performed when the weld enters the rolling mill, and the second step is performed when the weld is transitioned to the third stand in the rolling mill stand; the first step is to reduce to V1 before the weld enters the rolling mill, and the second step is to reduce to the set speed V2 at the exit shearing of the rolling mill when the weld is rolled to the third stand in the rolling mill stand, and V2 < V1; V1 is the maximum shearing speed Vmax of the exit roller shears of the rolling mill, and Vmax is 250 m / min; the working mode of the method comprises a normal strip division mode of the rolling mill, a dynamic variable-gauge strip division mode of the rolling mill, a normal sampling inspection strip division mode, and a dynamic variable-gauge sampling inspection strip division mode; the specific steps in the normal strip division mode of the rolling mill are as follows: first step: the strip before and after the weld has the same gauge, and the weld is reduced to the maximum shearing speed 250 m / min of the exit roller shears of the rolling mill when entering the rolling mill; second step: the weld is reduced to the set speed 100-200 m / min of the exit shearing of the rolling mill when leaving the third stand, and the weld is reduced to the set speed when leaving the third stand, and the weld head and tail are rolled at a low speed between the third stand and the fifth stand, so that the plate shape and the weld rolling quality of the product are controlled; the specific steps in the dynamic variable-gauge strip division mode of the rolling mill are as follows: first step: the strip before and after the weld has different gauges, and the weld is reduced to the maximum shearing speed 250 m / min of the exit roller shears of the rolling mill when entering the rolling mill; second step: when there is edge punching of the disc shears, the weld is reduced to the set speed 130 m / min of the exit shearing of the rolling mill when leaving the third stand; when there is no edge punching of the disc shears, the weld is reduced to the set speed 150 m / min of the exit shearing of the rolling mill when leaving the third stand; the specific steps in the normal sampling inspection strip division mode are as follows: first step: the weld is reduced to the exit speed 200 m / min of the normal shearing mode when entering the rolling mill; second step: the weld is reduced to the set speed 100 m / min of the exit shearing when leaving the third stand, and the weld head and tail are rolled at a low speed between the third stand and the fifth stand, so that the plate shape and the weld rolling quality of the product are controlled, and the maximum speed 100 m / min of the 10-meter upper inspection table of the strip head / tail is met; the specific steps in the dynamic variable-gauge sampling inspection strip division mode are as follows: first step: the weld is reduced to the speed 150 m / min or 130 m / min of the dynamic variable-gauge normal shearing mode when entering the rolling mill; second step: the weld is reduced to the set speed 100 m / min of the exit shearing when leaving the third stand, and the weld head and tail are rolled at a low speed between the third stand and the fifth stand, so that the plate shape and the weld rolling quality of the product are controlled, and the maximum speed 100 m / min of the 10-meter upper inspection table of the strip head / tail is met. ​