Stainless steel strip breakage control method for eighteen-roller five-rack tandem cold rolling mill

Abstract

The invention belongs to the technical field of stainless steel cold rolling, and provides a stainless steel strip breakage control method for an eighteen-roller five-rack tandem cold mill, which comprises the following steps of: controlling and adjusting deformation and rolling force; the roll bending value of each rack is adjusted to realize plate shape and edge drop control; the forward slip value and the tension fluctuation are controlled when the width and the thickness of rolled stainless steel are changed; controlling the rolling of the welding seam when the welding seam passes through a continuous mill; and finally, the replacement of the working roller is controlled. According to the method, the problem of large tension fluctuation caused by thickness and width changes and stopping and starting in the continuous rolling process of the stainless steel cold-rolled strip steel is solved through parameter setting and process adjustment of the continuous rolling mill, the strip breakage rate of the continuous rolling mill is reduced, and stable production operation is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of stainless steel cold rolling, and relates to a stainless steel strip break control method, in particular to a stainless steel strip break control method for an 18-roller five-stand cold rolling mill. Background Art

[0002] With the development of stainless steel cold rolling technology, 18-roller cold rolling mills are now widely used in the field of stainless steel cold rolling. On the one hand, strip breakage in the rolling mill is the main cause of accidents that affect the production efficiency of the unit. In the cold rolling production of stainless steel strips, due to the change in raw material thickness and width at the connection section and during the shutdown and start-up process, the actual tension of the strip is quite different from the set tension. At the same time, when the weld passes through the rolling mill, the tension will fluctuate violently, and it is very easy for the local force on the edge of the strip to be excessive, causing the strip to tear and break, which has a great impact on the continuous production of the rolling mill. Summary of the invention

[0003] The purpose of the present invention is to provide a stainless steel strip breakage control method for an 18-roller five-stand cold rolling mill, which can control the problem of large tension fluctuations caused by changes in thickness and width and stopping and starting of the stainless steel cold-rolled strip during the continuous rolling process by setting parameters of the continuous rolling mill and adjusting the process, thereby reducing the strip breakage rate of the continuous rolling mill and ensuring stable production operation.

[0004] The technical solution adopted by the present invention to achieve the above-mentioned purpose is:

[0005] A method for controlling stainless steel strip breakage in an 18-roller five-stand cold rolling mill, comprising:

[0006] S1. By adjusting the deformation and rolling force control, the total rolling deformation is controlled between 70% and 83%;

[0007] S2, realize plate shape and edge drop control by adjusting the bending roll value of each frame;

[0008] S3, control the fluctuation of the forward slip value when the width and thickness of the rolled stainless steel change;

[0009] S4, control tension fluctuations when the width and thickness of rolled stainless steel changes;

[0010] S5. Control the rolling of the weld when it passes through the continuous rolling mill;

[0011] S6. Control of work roll replacement;

[0012] Furthermore, the specific control method of S1 is:

[0013] When the rolled steel is ferritic stainless steel, the parameters of the 1# stand are set to deformation: 20-24%, rolling force 6000-7000kN; the parameters of the 2# stand are set to deformation: 22-26%, rolling force 6500-7500kN; the parameters of the 3# stand are set to deformation: 25-29%, rolling force 6500-7500kN; the parameters of the 4# stand are set to deformation: 25-29%, rolling force 5000-5500kN; the parameters of the 5# stand are set to deformation: 14-18%, rolling force 4000-4500kN;

[0014] When the rolled steel is austenitic stainless steel, the parameters of the 1# stand are set as deformation: 30-35%, rolling force 9000-10000 kN; the parameters of the 2# stand are set as deformation: 30-35%, rolling force 10000-11000 kN; the parameters of the 3# stand are set as deformation: 25-30%, rolling force 11500-12500 kN; the parameters of the 4# stand are set as deformation: 20-25%, rolling force 10000-11000 kN; the parameters of the 5# stand are set as deformation: 20-25%, rolling force 9000-10000 kN;

[0015] When the width of the rolled austenitic stainless steel is ≥1500mm and the thickness is ≤1.0mm, manually adjusting the deformation of the 1# rack to less than 28% can effectively control the appearance of strip surface defects and reduce the risk of strip breakage.

[0016] Furthermore, the specific control method of S2 is:

[0017] When the rolled steel is austenitic stainless steel, the parameters of the 1# stand are set to a bending roll value of 82-86%, the parameters of the 2# stand are set to a bending roll value of 47-51%, the parameters of the 3# stand are set to a bending roll value of 49-53%, the parameters of the 4# stand are set to a bending roll value of 52-56%, and the parameters of the 5# stand are set to a bending roll value of 62-64%;

[0018] When the rolled steel type is ferritic stainless steel, the parameters of the 1# stand are set to a bending roll value of -70--66%, the parameters of the 2# stand are set to a bending roll value of -15--10%, the parameters of the 3# stand are set to a bending roll value of -5-0%, the parameters of the 4# stand are set to a bending roll value of -50--45%, and the parameters of the 5# stand are set to a bending roll value of 10-15%.

[0019] Furthermore, the specific control method of S3 is:

[0020] Under normal rolling conditions, the forward slip value is required to be controlled between 0-1%. During the fluctuation of the forward slip value, the rolling speed is kept less than 50m / min, and the time when the forward slip value is less than 2% is less than or equal to 5s, otherwise the continuous rolling is stopped immediately.

[0021] Furthermore, the specific control method of S4 is:

[0022] The unit tension rule for the 5# rack is set as follows: the finished strip thickness is 0.8mm, and the unit tension of the 5# rack is controlled at 190-220N / mm 2 ; The finished strip thickness is 1.0mm, and the unit tension of the 5# rack is controlled at 200-220N / mm 2 ; The finished strip thickness is 1.2mm, and the unit tension of the 5# rack is controlled at 200-220N / mm 2 ; The finished strip thickness is 1.5mm, and the unit tension of the 5# rack is controlled at 180-205N / mm 2 ; Strip finished product thickness 2.0mm, 5# rack unit tension controlled at 175-195N / mm 2 ; The finished strip thickness is 2.5mm, and the unit tension of the 5# rack is controlled at 160-180N / mm 2 ; The finished strip thickness is 3.0mm, and the unit tension of the 5# rack is controlled at 155-175N / mm 2 When rolling ferritic stainless steel with a thickness below 1.2 mm, the unit tension at the 5# stand outlet will be 220 N / mm when the thickness or width of the steel plate is excessive or the plate shape fluctuates. 2 Reduced to 200N / mm 2 , and resume after stabilization;

[0023] The maximum width specification change is 400mm. Different tension control measures are formulated according to the transition width:

[0024] Width changes by 100mm, 5# rack outlet unit tension decreases by 25N / mm 2 ;

[0025] Width changes by 200mm, 5# rack outlet unit tension decreases by 30N / mm 2 ;

[0026] The width changes by 300mm, and the unit tension of the 5# rack outlet decreases by 35N / mm 2 ;

[0027] Width changes by 400mm, 5# rack outlet unit tension decreases by 40N / mm 2 ;

[0028] The maximum change in thickness specification is no more than 0.5mm. When the thickness specification changes, the unit tension of the 5# rack outlet is reduced by 40N / mm 2 After stopping and restarting, the unit tension of the strip steel is reduced by 40N / mm 2 .

[0029] Furthermore, the specific control method of S5 is: when the weld passes through the continuous rolling mill, the half-rolling mode is adopted, the rolling force is reduced by 20%, the bending roll value is manually increased by 5-10%, and the deviation value exceeds 20mm and then stops and adjusts.

[0030] Furthermore, the specific control method of S6 is: when the forward slip value is less than or equal to -0.5% for a long time or when the plate shape is abnormal at the outlet of the 5# frame, the working roll is replaced.

[0031] The beneficial effects of the present invention are:

[0032] (1) Improve production efficiency;

[0033] Reduce downtime. Belt breakage will cause the production line to stop, and it takes a long time to deal with the belt breakage accident. Controlling belt breakage can significantly reduce downtime and improve operation rate; increase production, stabilize the production process, reduce production interruptions caused by belt breakage, and enable the rolling mill to continue to operate efficiently and increase production.

[0034] (2) Reduce production costs;

[0035] Reduce scrap rate. Belt breakage produces scrap. Controlling belt breakage can reduce scrap rate and improve product yield rate. Reduce roll consumption. Belt breakage often causes roll damage. Controlling belt breakage can reduce roll replacement frequency, reduce roll consumption and maintenance costs. Reduce energy consumption. Stabilize production, reduce energy waste and improve energy efficiency.

[0036] (3) Improve product quality;

[0037] Ensure product dimensional accuracy. Belt breakage is often accompanied by dimensional deviation. Controlling belt breakage helps maintain product dimensional accuracy and meet customer requirements; improve surface quality and reduce surface defects caused by belt breakage, such as scratches and indentations.

[0038] (4) Ensure equipment safety;

[0039] Reduce equipment damage. Belt breakage may cause equipment damage. Controlling belt breakage can extend the service life of the equipment; reduce maintenance costs and reduce the number and cost of equipment maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is the production parameter table of 304 stainless steel with a width of 1550mm and a thickness of 4.5mm;

[0041] Figure 2 This is the production parameter table of 430 stainless steel with a width of 1250mm and a thickness of 3.0mm. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail. It should be understood that the specific implementation methods and embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0043] A method for controlling stainless steel strip breakage in an 18-roller five-stand cold rolling mill, comprising:

[0044] S1. By adjusting the deformation and rolling force control, the total rolling deformation is controlled between 70% and 83%;

[0045] When the rolled steel is ferritic stainless steel, the parameters of the 1# stand are set to deformation: 20-24%, rolling force 6000-7000kN; the parameters of the 2# stand are set to deformation: 22-26%, rolling force 6500-7500kN; the parameters of the 3# stand are set to deformation: 25-29%, rolling force 6500-7500kN; the parameters of the 4# stand are set to deformation: 25-29%, rolling force 5000-5500kN; the parameters of the 5# stand are set to deformation: 14-18%, rolling force 4000-4500kN;

[0046] When the rolled steel is austenitic stainless steel, the parameters of the 1# stand are set as deformation: 30-35%, rolling force 9000-10000 kN; the parameters of the 2# stand are set as deformation: 30-35%, rolling force 10000-11000 kN; the parameters of the 3# stand are set as deformation: 25-30%, rolling force 11500-12500 kN; the parameters of the 4# stand are set as deformation: 20-25%, rolling force 10000-11000 kN; the parameters of the 5# stand are set as deformation: 20-25%, rolling force 9000-10000 kN;

[0047] When the width of the rolled austenitic stainless steel is ≥1500mm and the thickness is ≤1.0mm, manually adjusting the deformation of the 1# rack to less than 28% can effectively control the appearance of strip surface defects and reduce the risk of strip breakage.

[0048] S2, realize plate shape and edge drop control by adjusting the bending roll value of each frame;

[0049] When the rolled steel is austenitic stainless steel, the parameters of the 1# stand are set to a bending roll value of 82-86%, the parameters of the 2# stand are set to a bending roll value of 47-51%, the parameters of the 3# stand are set to a bending roll value of 49-53%, the parameters of the 4# stand are set to a bending roll value of 52-56%, and the parameters of the 5# stand are set to a bending roll value of 62-64%;

[0050] When the rolled steel type is ferritic stainless steel, the parameters of the 1# frame are set to a bending roll value of -70--66%, the parameters of the 2# frame are set to a bending roll value of -15--10%, the parameters of the 3# frame are set to a bending roll value of -5-0%, the parameters of the 4# frame are set to a bending roll value of -50--45%, and the parameters of the 5# frame are set to a bending roll value of 10-15%.

[0051] S3, control the fluctuation of the forward slip value when the width and thickness of the rolled stainless steel change;

[0052] Under normal rolling conditions, the forward slip value is required to be controlled between 0-1%. During the fluctuation of the forward slip value, the rolling speed is kept less than 50m / min, and the time when the forward slip value is less than 2% is less than or equal to 5s, otherwise the continuous rolling is stopped immediately.

[0053] S4, control tension fluctuations when the width and thickness of rolled stainless steel changes;

[0054] The unit tension rule for the 5# rack is set as follows: the finished strip thickness is 0.8mm, and the unit tension of the 5# rack is controlled at 190-220N / mm 2 ; The finished strip thickness is 1.0mm, and the unit tension of the 5# rack is controlled at 200-220N / mm 2 ; The finished strip thickness is 1.2mm, and the unit tension of the 5# rack is controlled at 200-220N / mm 2 ; The finished strip thickness is 1.5mm, and the unit tension of the 5# rack is controlled at 180-205N / mm 2 ; Strip finished product thickness 2.0mm, 5# rack unit tension controlled at 175-195N / mm 2 ; The finished strip thickness is 2.5mm, and the unit tension of the 5# rack is controlled at 160-180N / mm 2 ; The finished strip thickness is 3.0mm, and the unit tension of the 5# rack is controlled at 155-175N / mm 2 When rolling ferritic stainless steel with a thickness below 1.2 mm, the unit tension at the 5# stand outlet will be 220 N / mm when the thickness or width of the steel plate is excessive or the plate shape fluctuates. 2 Reduced to 200N / mm 2 , and resume after stabilization;

[0055] The maximum width specification change is 400mm. Different tension control measures are formulated according to the transition width:

[0056] Width changes by 100mm, 5# rack outlet unit tension decreases by 25N / mm 2 ;

[0057] Width changes by 200mm, 5# rack outlet unit tension decreases by 30N / mm 2 ;

[0058] The width changes by 300mm, and the unit tension of the 5# rack outlet decreases by 35N / mm 2 ;

[0059] Width changes by 400mm, 5# rack outlet unit tension decreases by 40N / mm 2 ;

[0060] The maximum change in thickness specification is no more than 0.5mm. When the thickness specification changes, the unit tension of the 5# rack outlet is reduced by 40N / mm 2 After stopping and restarting, the unit tension of the strip steel is reduced by 40N / mm 2 .

[0061] S5. Control the rolling of the weld when it passes through the continuous rolling mill;

[0062] When the weld passes through the continuous rolling mill, adopt the half-rolling mode, reduce the rolling force by 20%, manually increase the bending roll value by 5-10%, and stop the mill before adjusting if the deviation value exceeds 20mm.

[0063] S6. Control of work roll replacement;

[0064] When the forward slip value is less than or equal to -0.5% for a long time or when the plate shape at the outlet of the 5# frame is abnormal, replace the working roll.

[0065] Example 1

[0066] Production of 1550mm width, 4.5mm thickness 304 stainless steel Figure 1 After the production is completed, the strip steel with a width of 1350mm and a thickness of 4.5mm will be produced. To ensure the smooth rolling of the width transition section, the strip steel unit tension of the 5# stand is increased from 219N / mm 2 , reduced to 189N / mm 2 The rolling pressure of each stand is adjusted routinely according to the width change.

[0067] Example 2

[0068] The parameters for producing 430 stainless steel with a width of 1250mm and a thickness of 3.0mm are as follows Figure 2 Parameter table for production, production is completed with the same 1250 width, 2.5mm thickness 430 transition, the 5# stand rolling mill unit tension from 175N / mm 2 Reduced to 135N / mm 2 The rolling pressure of each stand is adjusted routinely according to the thickness change.

[0069] The production process is controlled by parameter setting and process adjustment of the continuous rolling mill to solve the problem of large tension fluctuations caused by changes in thickness and width and stopping and starting of the stainless steel cold-rolled strip during the continuous rolling process, thereby reducing the strip breakage rate of the continuous rolling mill and ensuring stable production operation.

[0070] The above descriptions are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling stainless steel strip breakage in an 18-roller five-stand cold rolling mill, characterized in that: include: S1. By adjusting the deformation and rolling force control, the total rolling deformation is controlled between 70% and 83%; S2, realize plate shape and edge drop control by adjusting the bending roll value of each frame; S3, control the fluctuation of the forward slip value when the width and thickness of the rolled stainless steel change; S4, control tension fluctuations when the width and thickness of rolled stainless steel changes; S5. Control the rolling of the weld when it passes through the continuous rolling mill; S6. Control of working roll replacement.

2. The method for controlling stainless steel strip breakage in an 18-high five-stand cold rolling mill according to claim 1, characterized in that: The specific control method of S1 is: When the rolled steel is ferritic stainless steel, the parameters of the 1# stand are set to deformation: 20-24%, rolling force 6000-7000kN; the parameters of the 2# stand are set to deformation: 22-26%, rolling force 6500-7500kN; the parameters of the 3# stand are set to deformation: 25-29%, rolling force 6500-7500kN; the parameters of the 4# stand are set to deformation: 25-29%, rolling force 5000-5500kN; the parameters of the 5# stand are set to deformation: 14-18%, rolling force 4000-4500kN; When the rolled steel is austenitic stainless steel, the parameters of the 1# stand are set as deformation: 30-35%, rolling force 9000-10000 kN; the parameters of the 2# stand are set as deformation: 30-35%, rolling force 10000-11000 kN; the parameters of the 3# stand are set as deformation: 25-30%, rolling force 11500-12500 kN; the parameters of the 4# stand are set as deformation: 20-25%, rolling force 10000-11000 kN; the parameters of the 5# stand are set as deformation: 20-25%, rolling force 9000-10000 kN; When the width of the rolled austenitic stainless steel is ≥1500mm and the thickness is ≤1.0mm, manually adjusting the deformation of the 1# rack to less than 28% can effectively control the appearance of strip surface defects and reduce the risk of strip breakage.

3. The method for controlling stainless steel strip breakage in an 18-high five-stand cold rolling mill according to claim 1, characterized in that: The specific control method of S2 is: When the rolled steel is austenitic stainless steel, the parameters of the 1# stand are set to a bending roll value of 82-86%, the parameters of the 2# stand are set to a bending roll value of 47-51%, the parameters of the 3# stand are set to a bending roll value of 49-53%, the parameters of the 4# stand are set to a bending roll value of 52-56%, and the parameters of the 5# stand are set to a bending roll value of 62-64%; When the rolled steel type is ferritic stainless steel, the parameters of the 1# frame are set to a bending roll value of -70--66%, the parameters of the 2# frame are set to a bending roll value of -15--10%, the parameters of the 3# frame are set to a bending roll value of -5-0%, the parameters of the 4# frame are set to a bending roll value of -50--45%, and the parameters of the 5# frame are set to a bending roll value of 10-15%.

4. The method for controlling stainless steel strip breakage in an 18-high five-stand cold rolling mill according to claim 1, characterized in that: The specific control method of S3 is: Under normal rolling conditions, the forward slip value is required to be controlled between 0-1%. During the fluctuation of the forward slip value, the rolling speed is kept less than 50m / min, and the time when the forward slip value is less than 2% is less than or equal to 5s, otherwise the continuous rolling is stopped immediately.

5. The method for controlling stainless steel strip breakage in an 18-high five-stand cold rolling mill according to claim 1, characterized in that: The specific control method of S4 is: The unit tension rule for the 5# rack is set as follows: the finished strip thickness is 0.8mm, and the unit tension of the 5# rack is controlled at 190-220N / mm2; When the thickness of the finished strip is 1.0mm, the unit tension of the 5# frame is controlled at 200-220N / mm2; when the thickness of the finished strip is 1.2mm, the unit tension of the 5# frame is controlled at 200-220N / mm2; when the thickness of the finished strip is 1.5mm, the unit tension of the 5# frame is controlled at 180-205N / mm2; when the thickness of the finished strip is 2.0mm, the unit tension of the 5# frame is controlled at 175-195N / mm2; when the thickness of the finished strip is 2.5mm, the unit tension of the 5# frame is controlled at 160-180N / mm2; when the thickness of the finished strip is 3.0mm, the unit tension of the 5# frame is controlled at 155-175N / mm2; when rolling ferritic stainless steel below 1.2mm, the unit tension of the 5# frame outlet will be reduced from 220N / mm2 to 200N / mm2 when the thickness and width of the steel plate are excessive or the plate shape fluctuates, and then restored after stabilization; The maximum width specification change is 400mm. Different tension control measures are formulated according to the transition width: The width changes by 100mm, and the unit tension at the 5# rack outlet decreases by 25N / mm2; The width changes by 200mm, and the unit tension at the outlet of the 5# rack is reduced by 30N / mm2; The width changes by 300mm, and the unit tension at the 5# rack outlet decreases by 35N / mm2; The width changes by 400mm, and the unit tension at the 5# rack outlet decreases by 40N / mm2; The maximum change in thickness specification does not exceed 0.5mm. When the thickness specification transitions, the unit tension at the 5# rack outlet is reduced by 40N / mm2. The unit tension of the strip will be reduced by 40N / mm2 during the process of stopping and restarting the machine.

6. The method for controlling stainless steel strip breakage in an 18-high five-stand cold rolling mill according to claim 1, characterized in that: The specific control method of S5 is: when the weld passes through the continuous rolling mill, the half-rolling mode is adopted, the rolling force is reduced by 20%, the bending roll value is manually increased by 5-10%, and the deviation value exceeds 20mm, and the mill is stopped first and then adjusted.

7. The method for controlling stainless steel strip breakage in an 18-high five-stand cold rolling mill according to claim 1, characterized in that: The specific control method of S6 is: when the forward slip value is less than or equal to -0.5% for a long time or when the plate shape is abnormal at the outlet of the 5# frame, the working roll is replaced.

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