CN-116532476-B - Method for preventing strip steel from breaking

CN116532476BCN 116532476 BCN116532476 BCN 116532476BCN-116532476-B

Abstract

The application provides a method for preventing strip steel from breakage, which comprises the steps of welding a former strip steel and a latter strip steel, controlling the former strip steel and the latter strip steel to pass through a withdrawal and straightening machine in sequence for withdrawal and straightening, pickling in a pickling tank for pickling, rolling by a cold continuous rolling mill, and finally performing coiling separation and cutting operations to finish rolling of the strip steel. The scheme provided by the application solves the problems that the strip steel is easy to break and deviate in a welding line area in the dynamic change process of the specification because the specification and the yield strength of the previous strip steel and the next strip steel span greatly in the existing cold rolling production process, and the scheme provided by the application optimizes the mode of controlling the thickness of a rolling mill by adjusting the production process parameters in the dynamic change process of the strip steel specification, thereby preventing the strip steel break and deviation accidents in the welding line area in the dynamic change process of the specification, greatly improving the strip steel production efficiency and yield and effectively ensuring the product quality.

Inventors

SUN YONGJUN
WU YUNTAO
LU YAN
ZHAN HAIBING
SONG HAOYUAN
PAN YIYONG
XIANG YUANMAO
YU HAILONG
HU JIAXIN
MA KAI
HAO YAO

Assignees

北京首钢冷轧薄板有限公司

Dates

Publication Date: 20260512
Application Date: 20230509

Claims (10)

1. A method of preventing strip breakage, the method comprising: When a welding line at the welding position of the front coil of strip steel and the rear coil of strip steel passes through the tension leveler, controlling a set bending unit of the tension leveler to lift, controlling the tension of the tension leveler to be a first preset tension, and controlling the speed of the tension leveler to be a first preset speed; When the welding line enters the first pickling section, controlling the pickling speed of the strip steel to be a second preset speed, and when the welding line exits the third pickling section, controlling the pickling speed of the strip steel to be increased to the third preset speed; When the welding seam is rolled, sequentially passing through a first frame to a fifth frame, if the yield strength of the former strip steel is larger than that of the latter strip steel, and when the welding seam reaches a rolling mill inlet, adjusting a rolling mill shearing and rolling mode to a non-welding seam shearing mode, controlling the rolling speed of each frame from the first frame to the fifth frame to be a fourth preset speed, and controlling the tension between each frame from the first frame to the fourth frame to be reduced by 10% on the basis of the actual tension; After the welding seam reaches the second frame, the rolling force of the third frame is adjusted to the first preset rolling force, meanwhile, the front tension of the third frame is adjusted to the third preset tension, and the front tension of the fourth frame is adjusted to the fourth preset tension; After the welding seam reaches the third frame, controlling the rolling force of the fourth frame to be a second preset rolling force, and simultaneously controlling the front tension of the fourth frame to be reduced by 5% -10% on the basis of the fourth preset tension; after the welding seam reaches the fourth frame, controlling the working roll bending force and the middle roll bending force of the fourth frame to be increased by 10% -15% on the basis of setting the bending force; After the welding line passes through the fifth stand and reaches the outlet pinch roll, controlling the rolling speed of each stand from the first stand to the fifth stand to be a fifth preset speed, and executing the operations of coil separation and cutting to finish rolling of the strip steel.
2. The method of claim 1, wherein before the weld at the weld of the preceding roll of strip steel and the subsequent roll of strip steel passes through the withdrawal and straightening machine, the method further comprises: and shearing the tail part of the previous roll of strip steel and the head part of the next roll of strip steel according to the preset length, and welding the sheared previous roll of strip steel and the sheared next roll of strip steel.
3. The method of claim 2, wherein after welding the sheared previous roll of strip steel and the sheared subsequent roll of strip steel, the method further comprises: When the width of the front roll of strip steel is larger than that of the rear roll of strip steel and the width difference between the front roll of strip steel and the rear roll of strip steel is smaller than the preset width, the crescent moon is not cut off; And cutting off a crescent when the width of the front coil of strip steel is smaller than the width of the rear coil of strip steel or the width difference between the front coil of strip steel and the rear coil of strip steel is larger than or equal to the preset width, wherein the depth of the crescent is the preset depth.
4. The method of claim 1, wherein the first preset speed is 100m/min to 120m/min.
5. The method of claim 1, wherein the second preset speed is 80m/min to 100m/min.
6. The method of claim 1, wherein the third preset speed is 120m/min to 150m/min.
7. The method of claim 1, wherein the fourth preset speed is 100m/min to 120m/min.
8. The method of claim 1, wherein the fifth preset speed is 80m/min to 100m/min.
9. The method according to claim 1, wherein the method further comprises: If the yield strength of the former strip steel is smaller than that of the latter strip steel, when the welding line reaches the inlet of the rolling mill, controlling the rolling speed of each frame from the first frame to the fifth frame to be a sixth preset speed, and controlling the tension between each frame from the first frame to the fourth frame to be increased by 10% -15% on the basis of the actual tension; After the welding seam reaches the first frame, reducing the front tension of the first frame by 10% -15% on the basis of the first actual tension; after the welding seam reaches the second frame, controlling the front tension of the first frame to be adjusted to a first set tension, and simultaneously reducing the front tension of the second frame by 10% -15% on the basis of the second actual tension; after the welding seam reaches the third frame, controlling the front tension of the second frame to be adjusted to a second set tension, and simultaneously reducing the front tension of the third frame by 10% -15% on the basis of the third actual tension; after the welding seam reaches the fourth frame, controlling the front tension of the third frame to be adjusted to a third set tension, and simultaneously reducing the front tension of the fourth frame by 15% -20% on the basis of the fourth actual tension; and after the welding seam passes through the fifth stand and reaches the outlet pinch roll, controlling the front tension of the fourth stand to be a fourth set tension, and executing the operations of coiling and cutting to finish rolling the strip steel.
10. The method of claim 9, wherein the sixth preset speed is 120m/min to 150m/min.

Description

Method for preventing strip steel from breaking Technical Field The application belongs to the technical field of steel rolling, and particularly relates to a method for preventing strip steel from breakage. Background The production of the modern cold continuous rolling unit is influenced by planned production and stock of raw materials, the front and back coil specifications and the yield strength span are large in the cold rolling production process, the strip breakage of the rolling mill is caused, the production line is forced to stop, the effective operation rate of the rolling mill is reduced, waste products and roller damage are generated after strip breakage, and the product quality is also influenced. Based on the method, how to prevent the strip steel from breaking and deviating in the welding line area in the dynamic change process of the specification, improve the efficiency and the yield of strip steel production and ensure the quality of products is a technical problem to be solved urgently. Disclosure of Invention The application aims to provide a method for preventing strip breakage, which solves the problems that the strip breakage and deviation of a welding line area are easy to occur in the dynamic change process of the specification of strip steel due to large specification and yield strength span of a former strip steel and a latter strip steel in the existing cold rolling production process. Specifically, the application adopts the following technical scheme: When a welding line at the welding position of a front roll of strip steel and a rear roll of strip steel passes through a tension leveler, controlling a set bending unit of the tension leveler to lift, controlling the tension of the tension leveler to be a first preset tension, and controlling the speed of the tension leveler to be a first preset speed; When the welding line enters the first pickling section, controlling the pickling speed of the strip steel to be a second preset speed, and when the welding line exits the third pickling section, controlling the pickling speed of the strip steel to be increased to the third preset speed; When the welding seam is rolled, sequentially passing through a first frame to a fifth frame, if the yield strength of the former strip steel is larger than that of the latter strip steel, and when the welding seam reaches a rolling mill inlet, adjusting a rolling mill shearing and rolling mode to a non-welding seam shearing mode, controlling the rolling speed of each frame from the first frame to the fifth frame to be a fourth preset speed, and controlling the tension between each frame from the first frame to the fourth frame to be reduced by 10% on the basis of the actual tension; After the welding seam reaches the second frame, the rolling force of the third frame is adjusted to the first preset rolling force, meanwhile, the front tension of the third frame is adjusted to the third preset tension, and the front tension of the fourth frame is adjusted to the fourth preset tension; After the welding seam reaches the third frame, controlling the rolling force of the fourth frame to be a second preset rolling force, and simultaneously controlling the front tension of the fourth frame to be reduced by 5% -10% on the basis of the fourth preset tension; after the welding seam reaches the fourth frame, controlling the working roll bending force and the middle roll bending force of the fourth frame to be increased by 10% -15% on the basis of setting the bending force; After the welding line passes through the fifth stand and reaches the outlet pinch roll, controlling the rolling speed of each stand from the first stand to the fifth stand to be a fifth preset speed, and executing the operations of coil separation and cutting to finish rolling of the strip steel. In some embodiments of the application, based on the foregoing, the method further comprises shearing the tail portion of the preceding roll of strip steel and the head portion of the following roll of strip steel according to a preset length before the weld joint at the welding position of the preceding roll of strip steel and the following roll of strip steel passes through the withdrawal and straightening machine, and welding the sheared preceding roll of strip steel and the sheared following roll of strip steel. In some embodiments of the present application, based on the foregoing scheme, after welding the sheared previous roll of strip steel and the sheared subsequent roll of strip steel, the method further includes cutting off the crescent when the width of the previous roll of strip steel is greater than the width of the subsequent roll of strip steel and the width difference between the previous roll of strip steel and the subsequent roll of strip steel is less than a preset width, and cutting off the crescent when the width of the previous roll of strip steel is less than the width of the subsequent roll of strip steel or the width di