Method for reducing lateral differences in single stand cold rolling

Abstract

The present application relates to strip steel cold rolling technical field, including step one, determine horizontal roll gap;Step two, the installation and fixation of strip steel;Step three, determine the cross-sectional shape of the strip steel width direction;Step four, non-uniform extension rolling;Step five, uniform extension rolling.The single stand cold rolling method of the present application adopts non-uniform extension method to carry out cold rolling operation on strip steel through first pass and second pass, reduces the transverse thickness difference of cold rolled strip steel, can make subsequent third pass~fifth pass cold rolling more convenient, adopts uniform extension method to roll strip steel through third pass~fifth pass, can make the extension amount of each point in the width direction of strip steel as consistent as possible, so as to achieve the purpose of improving the shape, can reduce the transverse thickness difference of single stand cold rolling mill from 0.009mm~0.01mm to 0.007mm~0.008mm, through straightening when cold rolling the strip steel, can straighten the strip steel wave, is beneficial to the coiling and roll bite of strip steel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of strip steel cold rolling, in particular to a single-stand cold rolling method for reducing transverse difference. BACKGROUND

[0002] When the strip steel is cold-rolled, the transverse thickness difference is the thickness deviation in the width direction of the plate strip, that is, ΔH = H - h. The hot-rolled strip steel as a cold-rolled raw material has a large transverse thickness difference. After cold rolling, the transverse thickness difference is difficult to reduce to below 0.008 mm. Therefore, the single-stand cold rolling method for reducing transverse difference is needed.

[0003] After searching, the patent with the patent announcement number CN102029294B is a cold-rolled strip steel transverse thickness difference control method. The method is based on a profile gauge configured at the entrance of No. 1 stand to detect the cross section shape of the hot-rolled incoming material in real time to realize the feedforward control of the transverse thickness difference of the strip steel. The steps mainly include: (1) configuring a strip steel cross section shape detector at the entrance of No. 1 stand of the cold rolling mill to detect the cross section shape of the hot-rolled incoming material in real time; (2) calculating the characteristic value vector of the strip steel cross section at the entrance of No. 1 stand from the measured value of the cross section shape of the hot-rolled incoming material; (3) determining the compensation amount of the bending of the work roll, the bending of the intermediate roll, the tilting of the support roll, and the shifting of the upper and lower intermediate rolls according to the deviation between the actual value of the characteristic vector of the strip steel cross section at the entrance of No. 1 stand and the target value of the characteristic vector; and (4) taking the actual distribution of the roll gap exit flatness as a constraint condition when the transverse thickness difference control is output.

[0004] The existing single-stand cold rolling method for reducing transverse difference has the following defects:

[0005] The existing single-stand cold rolling method does not have a non-uniform extension cold rolling method for the strip steel at the first and second passes when the strip steel is cold-rolled, which cannot effectively reduce the transverse thickness difference of the strip steel and is not conducive to subsequent cold rolling operations, so that the strip steel still has a large thickness difference after cold rolling.

[0006] The existing single-stand cold rolling mill does not have a straightening function for the strip steel when the strip steel is cold-rolled, so that the strip steel is prone to upward bending during rolling, which is not conducive to coiling and roll bite into the rolled piece. SUMMARY

[0007] The present application aims to provide a single-stand cold rolling method for reducing transverse difference to solve the problems in the background art.

[0008] To achieve the above-mentioned purpose, the present application provides the following technical solution: a single-stand cold rolling method for reducing transverse difference, comprising the following steps: step one, determining the horizontal roll gap; step two, installing and fixing the strip steel; step three, determining the cross section shape in the width direction of the strip steel; step four, non-uniform extension rolling; and step five, uniform extension rolling.

[0009] In the above step one, after the new roll is installed, the zero position roll gap calibration program is started without the strip, the hydraulic press-down action of the rolling mill is performed, the roll stops rotating when the mill rolling force drops to 300t, the calibration is ended when the roll gap value reaches 8mm, and the deviation value of the two hydraulic cylinders at the calibration time is recorded. The purpose of this step is to determine the parallel position of the roll, which is used as a reference for the next adjustment.

[0010] In the above step two, the staff installs and fixes the strip on the rolling device according to the rolling requirements, passes one end of the strip between the rolling rolls, and fixes the end of the strip passing through the rolling rolls on the outside of the winding drum, which facilitates the winding of the strip during rolling.

[0011] In the above step three, after the strip is wound several turns on the coiler after passing through the rolling mill, the roll is pressed down, the closed-loop control of the plate shape instrument is started, the strip is started to run, and the rolling is started. After the plate shape measuring roll detects the plate shape of the strip, because the cross-sectional shape of the raw material is a combination of wedge shape and convex shape, the rolling mill plate shape adjustment follows the principle that each point in the width direction of the strip is uniformly extended. Therefore, when the plate shape of the strip is flat, the bending of the work roll, the inclination of the backup roll, and the axial movement position adjustment amount of the intermediate roll describe the roll gap shape of the current work roll, i.e. the cross-sectional shape in the width direction of the strip. At this time, the amount by which the inclination value of the hydraulic cylinder exceeds the calibration adjustment difference value is the difference between the high point and the low point of the cross-sectional thickness in the width direction of the strip, and the adjustment of the hydraulic bending roll also makes the actual work roll type have a slight bending deflection. The purpose of this step is to determine the degree of wedge shape and convex shape of the rolled piece, which provides a reference basis for the next step of reducing the transverse thickness difference adjustment.

[0012] In the above step four, when the plasticity of the rolled piece is large in the first pass and the second pass during the rolling of the strip, a non-uniform extension method is used to reduce the transverse thickness difference of the cold-rolled strip.

[0013] In the above step five, due to the use of the non-uniform extension method in the first pass and the second pass, the strip will have a wave shape. In the third pass to the fifth pass, a uniform extension method is used to make the extension amounts of each point in the width direction of the strip as consistent as possible, thereby achieving the purpose of improving the plate shape.

[0014] Preferably, in the above step one, when the hydraulic press-down action of the rolling mill is performed, the mill is rotated at a speed of 20m / min after the rolling force reaches 300t, and the average position of the two hydraulic cylinders at this time is set to zero by the computer when the rolling force reaches 600t. Roll gap horizontal adjustment is performed until the difference between the rolling forces on both sides is less than 10t. At this time, the difference between the positions of the two press-down hydraulic cylinders is the parallel position of the roll gap.

[0015] Preferably, the step three, when starting rolling, the strip shape is adjusted by computer feedback control of the work roll bending, the support roll inclination value and the intermediate roll axial movement position.

[0016] Preferably, the step three and the step four, when rolling the strip, one straightening roll S1 and S2 is added on each side of the rolling mill, the diameter of the straightening roll S1 and S2 is 150mm, the length is 1.9m-2m, during the rolling process, the straightening roll S1 and S2 is pressed down by the hydraulic cylinder, the pressing position is 5mm below the horizontal line of the strip, the action is to straighten the wave shape of the strip, which is beneficial to the coiling and the rolling bite.

[0017] Preferably, the step four adopts the non-uniform stretching method, the thickness of the strip in the width direction is relatively large, the pressing amount is relatively large, the stretching is relatively large, the thickness of the strip in the width direction is relatively small, the pressing amount is relatively small, and the stretching is relatively small.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] The single stand cold rolling method of the present application adopts the non-uniform stretching method to cold roll the strip in the first pass and the second pass, the briquetting reduces the transverse thickness difference of the cold rolled strip, which can make the subsequent third pass-fifth pass cold rolling more convenient, the uniform stretching method is adopted in the third pass-fifth pass to roll the strip, which can make the stretching amount of each point in the width direction of the strip as consistent as possible, so as to achieve the purpose of improving the plate shape, the transverse thickness difference of the single stand cold rolling mill rolled strip can be reduced from 0.009mm-0.01mm to 0.007mm-0.008mm, and the straightening can straighten the wave shape of the strip, which is beneficial to the coiling of the strip and the rolling bite. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The present application is a manufacturing step flow chart;

[0021] Figure 2 The present application is a single stand rolling mill structure diagram;

[0022] Figure 3 The present application is a strip rolling thickness diagram;

[0023] Figure 4 The present application is an intermediate roll movement diagram. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of the present application.

[0025] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0026] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "provided with", "connection" and the like should be broadly understood, for example, "connection" can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements. For a person of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0027] Please refer to Figure 1 The present application provides an embodiment:

[0028] Embodiment 1

[0029] The method for reducing the transverse difference of single-stand cold rolling includes the following steps: step one, determining the horizontal roll gap; step two, installing and fixing the strip steel; step three, determining the cross-sectional shape in the width direction of the strip steel; step four, non-uniform extension rolling; and step five, uniform extension rolling.

[0030] In the above step one, after the new roll is installed, the zero-position roll gap calibration program is started under the condition of no strip steel, the hydraulic pressure of the rolling mill is lowered, when the rolling force of the stand is reduced to 300t, the roll stops rotating, the roll gap value is continued to be raised, and when the roll gap value reaches 8mm, the calibration is ended, and the deviation value of the hydraulic cylinders on both sides at the time of calibration is recorded. The purpose of this step is to determine the parallel position of the roll, which serves as a reference for the next adjustment.

[0031] In the step two, the workers install and fix the strip steel on the rolling device according to the rolling requirement, pass one end of the strip steel between the rolling rollers, and fix the one end of the strip steel passing through the rolling rollers on the outside of the winding drum, so as to facilitate the winding of the strip steel during the rolling process.

[0032] In the step three, after the strip steel passes through the rolling mill and winds several turns on the coiler, the rolling rollers are pressed, the closed-loop control of the plate shape instrument is started, the strip steel is started to run, the rolling is started, and the plate shape measuring roller detects the plate shape of the strip steel. Because the cross-sectional shape of the raw material is a combination of wedge shape and convex shape, the rolling mill plate shape adjustment follows the principle that each point in the width direction of the strip steel is uniformly extended. Therefore, when the plate shape of the strip steel is flat, the bending of the work roll, the inclination of the support roll, and the axial movement position adjustment amount of the intermediate roll describe the roll gap shape of the current work roll, that is, the cross-sectional shape in the width direction of the strip steel. At this time, the amount of the inclination value of the hydraulic cylinder exceeding the calibration adjustment difference value is the difference between the high point and the low point of the cross-sectional thickness in the width direction of the strip steel. The adjustment of the hydraulic bending roll also makes the actual work roll type have a slight bending deflection. The purpose of this step is to determine the degree of wedge shape and convex shape of the rolled piece, and to provide a reference basis for the adjustment of reducing the transverse thickness difference in the next step.

[0033] In the step four, when the rolled piece is plastic in the first pass and the second pass, a non-uniform extension method is used to reduce the transverse thickness difference of the cold-rolled strip steel.

[0034] In the step five, because the non-uniform extension method is used in the first pass and the second pass, the strip steel will appear wavy. In the third pass to the fifth pass, a uniform extension method is used to make the extension amount of each point in the width direction of the strip steel as consistent as possible, so as to achieve the purpose of improving the plate shape.

[0035] Example 2

[0036] In step one, when the rolling force reaches 300t, the frame rotates at a speed of 20m / min, when the rolling force reaches 600t, the computer sets the average position of the two hydraulic cylinders as zero, and adjusts the roll gap horizontally until the difference of the rolling force is less than 10t, at this time, the difference of the two hydraulic cylinders is the parallel position of the roll gap, in step three, when the rolling starts, the computer feedback controls the bending of the work roll, the inclination of the support roll, and the axial movement of the intermediate roll to adjust the strip shape, in step three and step four, when the strip is rolled, one straightening roll S1 and S2 is added on each side of the rolling mill, the diameter of the straightening roll is 150mm, and the length is 1.9m-2m, during the rolling process, the straightening roll S1 and S2 are pressed down by the hydraulic cylinder, and the pressing position is 5mm below the horizontal line of the strip, the function is to straighten the strip and facilitate the winding and the rolling of the workpiece, in step four, the non-uniform extension method is adopted, the pressing amount of the place with large thickness in the width direction of the strip is relatively large, and the extension is relatively large, the pressing amount of the place with small thickness in the width direction of the strip is relatively small, and the extension is relatively small.

[0037] The parts not described in the present application are the known technology of those skilled in the art.

[0038] Finally, it should be pointed out that the above specific embodiments are only used to illustrate the technical solutions of the present application and are not limiting, although the present application has been described in detail with reference to the embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified and replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A method for reducing transverse differences in single-stand cold rolling, comprising: step one, determining the horizontal roll gap; step two, installing and fixing the strip; step three, determining the cross-sectional shape of the strip in the width direction; step four, non-uniform elongation rolling; and step five, uniform elongation rolling; characterized in that: In step one above, after the new roll is installed on the mill, the zero-position roll gap calibration program is started under the condition of no strip steel. The mill hydraulic pressure is pressed down. When the mill stand rolling force drops to 300t, the roll stops rotating. It continues to be lifted. When the roll gap value reaches 8mm, the calibration ends. The deviation values ​​of the hydraulic cylinders on both sides during calibration are recorded. The purpose of this step is to determine the parallel position of the roll, which will serve as a reference for the next adjustment. In step two above, the workers install and fix the strip steel on the rolling device according to the rolling requirements, pass one end of the strip steel through the rolling rolls, and fix the end of the strip steel that has passed through the rolling rolls to the outside of the winding drum, so as to facilitate the winding of the strip steel during the rolling process. In step three above, after the strip passes through the rolling mill and is wound around the coiler, it is pressed down on the rolls and put into the closed-loop control of the strip shape measuring instrument. The strip runs and rolling begins. After the strip shape measuring roll detects the strip shape, since the cross-sectional shape of the raw material is a combination of wedge and convex shape, the rolling mill shape adjustment follows the principle of uniform extension at all points in the width direction of the strip. Therefore, when the strip shape is straight, the tilt value of the bending roll of the work roll, the tilt value of the support roll, and the axial movement position adjustment of the intermediate roll describe the roll gap shape of the current work roll, that is, the cross-sectional shape in the width direction of the strip. At this time, the amount by which the tilt value of the hydraulic cylinder exceeds the calibrated adjustment difference is the difference between the high point and the low point of the cross-sectional thickness in the width direction of the strip. The adjustment of the hydraulic bending roll also makes the actual work roll shape have a slight bending deflection. The purpose of this step is to determine the degree of wedge and convex shape of the rolled piece, and to provide a reference for the next step of reducing the transverse thickness difference. In step four above, when rolling the strip steel, when the plasticity of the first and second passes is relatively large, a non-uniform elongation method is adopted to reduce the transverse thickness difference of the cold-rolled strip steel. In step five above, because the first and second passes use a non-uniform elongation method, the strip will have a wavy shape. When rolling the strip in the third to fifth passes, a uniform elongation method is used to make the elongation at each point in the width direction of the strip tend to be consistent, thereby achieving the purpose of improving the strip shape. When the rolling mill hydraulically presses down in step one, the stand rotates at a speed of 20 m / min after the rolling force reaches 300t. When the rolling force reaches 600t, the computer sets the average position of the hydraulic cylinders on both sides to zero and adjusts the roll gap horizontally until the difference between the two sides of the rolling force is less than 10t. At this time, the difference between the positions of the two pressing hydraulic cylinders is the parallel position of the roll gap. In step three, when rolling begins, the strip shape is adjusted by computer feedback control of the bending of the work roll, the inclination of the support roll, and the axial movement of the intermediate roll. In steps three and four, during the strip rolling process, a straightening roll S1 and a straightening roll S2 are added on each side of the mill. The straightening rolls have a diameter of 150mm and a length of 1.9m to 2m. During the rolling process, the straightening rolls S1 and S2 are pressed down by hydraulic cylinders. The pressing position is 5mm below the horizontal line of the strip. Their function is to straighten the strip's waviness, which is beneficial for coiling and for the rolls to bite into the workpiece.

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