A method for predicting the thermal crown of a cold-rolling and skin-passing process roll
By establishing models of plastic deformation heat and frictional heat, combined with a roll temperature field model, the problem of inaccurate prediction of thermal crown during cold rolling leveling was solved, achieving accurate prediction of roll thermal crown and improving the strip shape quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TANGSHAN IRON & STEEL GROUP
- Filing Date
- 2026-03-19
- Publication Date
- 2026-06-19
AI Technical Summary
Existing technologies fail to adequately consider the dynamic changes in frictional heat along the roll length and contact arc length during cold rolling leveling, resulting in inaccurate thermal crown prediction and affecting the strip shape quality.
By collecting key equipment characteristic parameters, rolling process parameters, and process lubrication system parameters of the cold rolling leveling unit, a plastic deformation heat and friction heat model is established. Combined with the roll temperature field model, the roll surface temperature is calculated, and the roll thermal crown is predicted.
It enables accurate prediction of the thermal crown of the rolls during the cold rolling leveling process, thereby improving the control accuracy of the finished sheet shape quality.
Smart Images
Figure CN122244973A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of cold rolling leveling technology, specifically relating to a method for predicting the thermal crown of rolls during the cold rolling leveling process. Background Technology
[0002] With the growth of the domestic economy and the formulation of "dual carbon" targets, the steel industry is gradually moving towards high-end, intelligent, and green development, with high-quality steel becoming a key product in the market. Cold rolling leveling is a crucial process for improving the surface quality of strip steel, enhancing its mechanical properties, and controlling its shape. During this process, the intense friction between the rolls and the strip steel, as well as the plastic deformation of the strip steel itself, generates a large amount of heat, causing a significant increase in the surface temperature of the rolls. Due to uneven cooling conditions, contact states, and compressive stress distribution along the length of the rolls, the temperature field of the rolls exhibits a non-uniform distribution. The resulting difference in thermal expansion forms thermal crown, which has a significant impact on the strip steel's shape quality. Good strip steel shape quality plays a vital role in the efficiency of the production line.
[0003] Previous studies have mostly simplified the heat source to a single interfacial frictional heat, neglecting the internal heat generated by the strip in the deformation zone due to intense plastic deformation. During the leveling process, although the deformation amount is small, the stress state in the deformation zone is complex, and the power density of plastic deformation is high, so the heat generated cannot be ignored. Furthermore, the treatment of frictional heat usually adopts the average heat flux density or simple distribution, without fully considering the dynamic changes of frictional heat along the length of the roll and the contact arc length. Summary of the Invention
[0004] The purpose of this invention is to provide a simple and rationally designed method for predicting the thermal crown of rolls in the cold rolling leveling process in order to solve the above-mentioned problems.
[0005] The present invention achieves the above objectives through the following technical solutions: A method for predicting the thermal crown of rolls during cold rolling leveling includes the following steps: Step 1, collecting characteristic parameters; Step 2, collecting rolling process parameters; Step 3, collecting process lubrication system parameters; Step 4, calculating rolling pressure; Step 5, calculating heat of plastic deformation; Step 6, calculating heat energy of sliding friction; Step 7, establishing a temperature field calculation model for the roll system; Step 8, calculating thermal crown; and Step 9, predicting the thermal crown of rolls. In step one above, the key equipment characteristic parameters of the cold rolling leveling unit are first collected. In step two above, after the data collection in step one is completed, the rolling process parameters continue to be collected. In step three above, after the rolling process parameters in step two are collected, the relevant parameters of the process lubrication system are collected. In step four above, after the parameters from step three are collected, the rolling pressure of the cold rolling leveling mill is calculated. The expression for the rolling pressure is shown in equation (1): (1) in: In the formula: L is the contact arc length of the rolling deformation zone; f is the unit rolling force; The coefficient of friction; This represents the initial resistance to strip deformation. , , This is the influence coefficient of equivalent deformation resistance; , The coefficient representing the influence of the contact arc length in the rolling deformation range; In step five above, the heat energy generated by the plastic deformation of the strip during the cold rolling process is calculated based on the plastic deformation of the strip during the rolling process, and is expressed by equation (3): (3) In step six above, based on the friction mechanism, the heat energy generated by the relative sliding friction between the strip and the roll during the cold rolling leveling process is calculated and expressed by equation (4): (4) In the formula: The heat energy generated by friction. Where V is the coefficient of friction and V is the rolling speed. For rolling pressure; In step seven above, based on the calculations of the main heat sources generated during the cold rolling leveling process, a calculation model of the temperature field of the rolling mill roll system is established, and the roll boundary conditions are set: Rolling conditions of the rolls: Conditions of the non-rolled portion of the rolls: (6) The heat conduction equations for the temperature distribution of the roll along the axial and radial directions are shown in equation (7): In step eight above, based on the above calculation of the roll temperature field, a roll thermal crown prediction model is established during the cold rolling leveling process, and the thermal crown of the cold rolling leveling roll is calculated as shown in equation (8): (8) In step nine above, the thermal crown of the rolls during the cold rolling leveling process is output, thus completing the prediction of the thermal crown of the rolls during the cold rolling leveling process.
[0006] Preferably, in step one, the characteristic parameters include the working roll radius R, elastic modulus E, and Poisson's ratio.
[0007] Preferably, in step two, the rolling process parameters include the strip entry thickness. Export thickness of strip Strip width B, strip elongation Critical rolling pressure And rolling speed V.
[0008] Preferably, in step three, the relevant parameters of the process lubrication regime include l being the leveling fluid flow rate. c represents the leveling solution temperature and c represents the leveling solution concentration.
[0009] Preferably, in step four, The work roll's elastic flattening radius, , Elongation; ; , Foretension and backtension.
[0010] Preferably, in step five, the formula is: The heat energy generated by the plastic deformation of the rolled piece. For the strip entry thickness, , This represents the average contact stress. , This refers to absorption efficiency.
[0011] Preferably, in step seven, the formula is: For the specific heat of the work roll, The density of the rolls, The thermal conductivity of the roll. For the temperature of the rolling mill rolls, For strip temperature, The heat transfer coefficient between the rolls and the leveling fluid. This refers to the temperature of the leveling liquid.
[0012] Preferably, in step eight, the formula is: The coefficient of thermal expansion is... Let R be the Poisson's ratio of the work roll material, R be the work roll radius, r be the radial coordinate value on the roll, and z be the axial coordinate of the roll. The temperature distribution along the axial direction of the roller body, This represents the initial temperature distribution of the rolls.
[0013] The beneficial effects of this invention are as follows: Unlike existing technologies, this invention collects key equipment characteristic parameters, rolling process parameters, and process lubrication system parameters of the cold rolling leveling unit. Based on these parameters, it establishes models of plastic deformation heat, frictional heat, and roll temperature field, calculates the roll surface temperature during the rolling process, and completes the calculation of roll thermal crown during cold rolling leveling. This allows for accurate prediction of roll thermal crown, ensuring the quality of the finished sheet shape. Compared to the traditional approach that simplifies the heat source to a single interface frictional heat, this invention fully considers the dynamic changes of frictional heat along the roll length and contact arc length, achieving accurate prediction of roll thermal crown during cold rolling leveling and improving the accuracy of the prediction. Attached Figure Description
[0014] Figure 1 This is a flowchart of the method for predicting the thermal crown of rolls during the cold rolling leveling process according to the present invention; Figure 2 This is a schematic diagram of the calculation results of the roll temperature field of the present invention; Figure 3 This is a schematic diagram of the calculation results of the roll thermal crown of the present invention; Figure 4 This is a schematic diagram of the calculation results of the roll temperature field of the present invention; Figure 5 This is a schematic diagram of the calculation results of the roll thermal crown of the present invention. Detailed Implementation
[0015] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.
[0016] Example 1: Taking a steel grade with a specification of 0.63mm × 930mm as an example, calculations are performed.
[0017] Please see Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5A method for predicting the thermal crown of rolls during cold rolling leveling includes the following steps: Step 1, collecting characteristic parameters; Step 2, collecting rolling process parameters; Step 3, collecting process lubrication system parameters; Step 4, calculating rolling pressure; Step 5, calculating heat of plastic deformation; Step 6, calculating heat energy of sliding friction; Step 7, establishing a temperature field calculation model for the roll system; Step 8, calculating thermal crown; and Step 9, predicting the thermal crown of rolls. In step one above, the key equipment characteristic parameters of the leveling unit are collected, mainly including: work roll radius R=220mm; elastic modulus E=206GPa; Poisson's ratio ν=0.3; In step two above, relevant rolling process parameters are collected, mainly including: the entry thickness of the strip. =0.63mm, strip exit thickness =0.62mm, strip width B=930mm, strip initial deformation resistance =251MPa and rolling speed V=261m / min; In step three above, relevant parameters of the process lubrication regime are collected, mainly including: leveling fluid flow rate l = 33 L·min -1 Leveling liquid temperature =29 ℃; leveling solution concentration c=2.4%; In step four above, according to the formula: A calculation model for rolling pressure in a cold rolling leveling mill is used to calculate relevant parameter values. The contact arc length in the rolling deformation zone is selected as a relevant parameter: the influence coefficient of the contact arc length in the rolling deformation zone. =0.2、 =0.01, then the contact arc length L of the rolling deformation zone is 3.65; select the deformation resistance influence coefficient, =0.1、 =0.04、 =1.1, initial deformation resistance =251MPa, pretension =47kN, back tension =52kN, then the equivalent deformation resistance =276.27MPa; Selected parameters related to unit rolling force: friction coefficient =0.0126, combined with the parameters given above, the unit rolling force f = 1027.58kN; considering the unit rolling force and the contact arc length of the rolling deformation zone, the rolling pressure P = 3834.59kN; In step five above, according to the formula: A thermal model of plastic deformation during cold rolling and leveling was used to calculate relevant parameter values: a thermal efficiency correction coefficient of 0.9 was selected, and the following parameters related to average pressure were chosen: strip width B = 930 mm, contact arc length of the rolling deformation zone L = 3.65. The average contact stress was then calculated. =1129.66MPa, calculate the true strain based on the strip inlet and outlet thicknesses. =0.016, select volumetric flow rate related parameters, strip outlet thickness =0.62mm, rolling speed V=261m / min, then the volumetric flow rate =0.0025 Calculate the total heat power of plastic deformation by combining the average contact stress, true strain, and volumetric flow rate. =30.95kW; In step six above, according to the formula: The frictional heat model of the cold rolling leveling process in the paper is used to calculate the friction coefficient by selecting relevant parameters. =0.026, rolling pressure P=3784.35kN, rolling speed V=4.35m / s, then the heat energy generated by the relative sliding friction between the strip and the rolls is... =11.13kW; In step seven above, based on the calculations of the main heat sources generated during the cold rolling and leveling process, according to the formula: The established rolling process roll system temperature field calculation model is used to solve the working roll temperature field. The formula calculates the temperature value at the highest point. The calculation process uses the roll segment calculation. Heat transferred to the work roller: =0.15*(30.95+11.13)=8.416kW, where The heat distribution coefficient represents the balance between the heat absorbed by the rolls and the heat carried away by the leveling fluid under steady-state rolling conditions. , For leveling liquid temperature, For the surface temperature of the rolls, convective heat transfer system =3500 For effective cooling area =1.285 Then the surface temperature of the roll is: =29 + 8416 / 4497.5 = 30.4℃, the calculated result of the axial surface temperature of the roll is as follows. Figure 2 As shown; In step eight above, based on the calculation of the roll temperature field described above, according to the formula: In the cold rolling leveling process, a model for predicting the thermal crown of rolls was used. Relevant parameters were selected to calculate the thermal crown of the rolls. The roll temperature field values were selected as shown in Figure (1). The initial temperature of the rolls was 25℃; the radius of the work rolls was R=220mm; the material Poisson's ratio was 0.3; and the coefficient of thermal expansion was 0.3. Then, by simplifying equation (8), we get... Solve for the thermal crown of the roll, and the calculation results are as follows: Figure 3 As shown; In step nine above, the prediction of the thermal crown of the rolls during the cold rolling leveling process is completed.
[0018] Example 2: Taking a sample with dimensions of 0.54mm × 960mm as an example, calculations are performed.
[0019] Please see Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 A method for predicting the thermal crown of rolls during cold rolling leveling includes the following steps: Step 1, collecting characteristic parameters; Step 2, collecting rolling process parameters; Step 3, collecting process lubrication system parameters; Step 4, calculating rolling pressure; Step 5, calculating heat of plastic deformation; Step 6, calculating heat energy of sliding friction; Step 7, establishing a temperature field calculation model for the roll system; Step 8, calculating thermal crown; and Step 9, predicting the thermal crown of rolls. In step one above, key equipment characteristic parameters of the leveling unit are collected, mainly including: work roll radius R = 220 mm; elastic modulus E = 206 GPa; Poisson's ratio. =0.3; In step two above, relevant rolling process parameters are collected, mainly including: the entry thickness of the strip. =0.54mm; Export thickness of strip =0.52mm; strip width B=960mm; initial deformation resistance of strip =246MPa; Rolling speed V=253m / min; In step three above, relevant parameters of the process lubrication regime are collected, mainly including: leveling fluid flow rate l = 33 L·min -1 Leveling liquid temperature =30 ℃; leveling solution concentration c=2.7%; In step four above, according to the formula: , The calculation model of rolling pressure in the cold rolling leveling mill is used to calculate relevant parameter values and select the contact arc length related parameters in the rolling deformation zone: the influence coefficient of contact arc length in the rolling deformation zone. =0.5、 =0.008, then the contact arc length L of the rolling deformation zone is 3.53; select the deformation resistance influence coefficient, =0.1、 =0.03、 =1.1, initial deformation resistance =246MPa, pretension =49kN, back tension =42kN, then the equivalent deformation resistance =270.77MPa; Selected parameters related to unit rolling force: friction coefficient =0.0126, and combining the parameters given above, the unit rolling force is... =997.08kN; Considering the unit rolling force and the contact arc length of the rolling deformation zone, the rolling pressure P=3516.94kN; In step five above, according to the formula: The thermal model of plastic deformation in the cold rolling and leveling process was used to calculate relevant parameter values: a thermal efficiency correction coefficient of 0.9 was selected; the average pressure parameters were selected as follows: strip width B = 960 mm, contact arc length of the rolling deformation zone L = 3.53, and the average contact stress was calculated. =1037.81MPa; Calculate the true strain based on the strip inlet and outlet thicknesses. =0.038; Select relevant parameters for volumetric flow rate, strip outlet thickness =0.62mm, rolling speed V=253m / min, then the volumetric flow rate =0.0021 Calculate the total heat power of plastic deformation by combining the average contact stress, true strain, and volumetric flow rate. =66.2kW; In step six above, according to the formula: The frictional heat model of the cold rolling leveling process in the paper is used to calculate the friction coefficient by selecting relevant parameters. =0.026, rolling pressure P=3516.94kN, rolling speed V=4.22m / s, then the heat energy generated by the relative sliding friction between the strip and the rolls is... =10.03kW; In step seven above, based on the calculations of the main heat sources generated during the cold rolling and leveling process, according to the formula: The established rolling process roll system temperature field calculation model is used to solve the work roll temperature field. The formula expresses the temperature value at the highest point. The calculation process uses the roll segment calculation. Heat transferred to the work roller: =0.15*(66.2+10.03)=11.43kW. Where... The heat distribution coefficient represents the balance between the heat absorbed by the rolls and the heat carried away by the leveling fluid under steady-state rolling conditions. ,in For leveling liquid temperature, The surface temperature of the roll is the convective heat transfer coefficient. =3500 For effective cooling area =1.327 Then the surface temperature of the roll is: =30 + 8416 / 4497.5 = 32.46℃. The calculated result for the axial surface temperature of the roll is as follows: Figure 4 As shown; In step eight above, based on the calculation of the roll temperature field described above, according to the formula: A model for predicting the thermal crown of rolls during cold rolling leveling was established. Relevant parameters were selected, and the thermal crown of the rolls was calculated. The roll temperature field values were selected as shown in Figure (1); the initial roll temperature was 25℃; the work roll radius R = 220mm; the material Poisson's ratio was 0.3; and the coefficient of thermal expansion was... Then, by simplifying equation (8), we get... Solve for the thermal crown of the roll. The calculation results are as follows: Figure 5 As shown; In step nine above, the prediction of the thermal crown of the rolls during the cold rolling leveling process is completed.
[0020] It should be noted that this method for predicting the thermal crown of rolls during the cold rolling leveling process involves collecting characteristic parameters of key equipment in the cold rolling leveling unit, rolling process parameters, and relevant parameters of the process lubrication regime. Based on these parameters, a model of plastic deformation heat, frictional heat, and a roll temperature field model are established. The surface temperature of the rolls during the rolling process is calculated, and the thermal crown of the rolls during the cold rolling leveling process is calculated. This allows for accurate prediction of the roll's thermal crown, ensuring the quality of the finished sheet shape. Compared to the traditional method that simplifies the heat source to a single interface frictional heat, this method fully considers the dynamic changes of frictional heat along the roll length and contact arc length, achieving accurate prediction of the roll's thermal crown during the cold rolling leveling process and improving the accuracy of the prediction.
[0021] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.
Claims
1. A method for predicting the thermal crown of rolls during cold rolling leveling, comprising: Step 1, collecting characteristic parameters; Step 2, collecting rolling process parameters; Step 3, collecting process lubrication system parameters; Step 4, calculating rolling pressure; Step 5, calculating heat of plastic deformation; Step 6, calculating heat energy of sliding friction; Step 7, establishing a calculation model of the roll system temperature field; Step 8, calculating thermal crown; Step 9, predicting the thermal crown of rolls; characterized in that: In step one above, the key equipment characteristic parameters of the cold rolling leveling unit are first collected. In step two above, after the data collection in step one is completed, the rolling process parameters continue to be collected. In step three above, after the rolling process parameters in step two are collected, the relevant parameters of the process lubrication system are collected. In step four above, after the parameters from step three are collected, the rolling pressure of the cold rolling leveling mill is calculated. The expression for the rolling pressure is shown in equation (1): (1) in: (2) In the formula: L is the contact arc length of the rolling deformation zone; f is the unit rolling force; Equivalent deformation resistance; The coefficient of friction; This represents the initial resistance to strip deformation. , , This is the influence coefficient of equivalent deformation resistance; , The coefficient representing the influence of the contact arc length in the rolling deformation range; In step five above, the heat energy generated by the plastic deformation of the strip during the cold rolling process is calculated based on the plastic deformation of the strip during the rolling process, and is expressed by equation (3): (3) In step six above, based on the friction mechanism, the heat energy generated by the relative sliding friction between the strip and the roll during the cold rolling leveling process is calculated and expressed by equation (4): (4) In the formula: The heat energy generated by friction. Where V is the coefficient of friction and V is the rolling speed. For rolling pressure; In step seven above, based on the calculations of the main heat sources generated during the cold rolling leveling process, a calculation model of the temperature field of the rolling mill roll system is established, and the roll boundary conditions are set: Rolling conditions of the rolls: (5) Conditions of the non-rolled portion of the rolls: (6) The heat conduction equations for the temperature distribution of the roll along the axial and radial directions are shown in equation (7): In step eight above, based on the above calculation of the roll temperature field, a roll thermal crown prediction model is established during the cold rolling leveling process, and the thermal crown of the cold rolling leveling roll is calculated as shown in equation (8): ； (8) In step nine above, the thermal crown of the rolls during the cold rolling leveling process is output, thus completing the prediction of the thermal crown of the rolls during the cold rolling leveling process.
2. The method for predicting the thermal crown of rolls in the cold rolling leveling process according to claim 1, characterized in that: In step one, the characteristic parameters include the working roll radius R, elastic modulus E, and Poisson's ratio.
3. The method for predicting the thermal crown of rolls in the cold rolling leveling process according to claim 1, characterized in that: In step two, the rolling process parameters include the strip entry thickness. Export thickness of strip Strip width B, strip elongation strip yield strength Critical rolling pressure And rolling speed V.
4. The method for predicting the thermal crown of rolls in the cold rolling leveling process according to claim 1, characterized in that: In step three, the relevant parameters of the process lubrication system include l, which is the leveling fluid flow rate. c represents the leveling solution temperature and c represents the leveling solution concentration.
5. The method for predicting the thermal crown of rolls in the cold rolling leveling process according to claim 1, characterized in that: In step four, The work roll's elastic flattening radius, , Elongation; This is the coefficient of influence of deformation resistance; , Foretension and backtension.
6. The method for predicting the thermal crown of rolls in the cold rolling leveling process according to claim 1, characterized in that: In step five, the formula is: The heat energy generated by the plastic deformation of the rolled piece. For the strip entry thickness, For the export thickness of the strip, This represents the average contact stress. Volumetric flow rate, This refers to absorption efficiency.
7. The method for predicting the thermal crown of rolls in the cold rolling leveling process according to claim 1, characterized in that: In step seven, the formula is: For the specific heat of the work roll, The density of the rolls, The thermal conductivity of the roll. For the temperature of the rolling mill rolls, The heat transfer coefficient of the rolling portion on the roll body. For strip temperature, The heat transfer coefficient between the rolls and the leveling fluid. This refers to the temperature of the leveling liquid.
8. The method for predicting the thermal crown of rolls in the cold rolling leveling process according to claim 1, characterized in that: In step eight, the formula is: Roll thermal crown, The coefficient of thermal expansion is... Let R be the Poisson's ratio of the work roll material, R be the work roll radius, r be the radial coordinate value on the roll, and z be the axial coordinate of the roll. The temperature distribution along the axial direction of the roller body, This represents the initial temperature distribution of the rolls.