Method for controlling the coiling tension of a cold rolled strip
By dividing the coiling process into three stages and adjusting the tension according to different factors, the problem of improper tension control during the coiling of cold-rolled strip steel was solved, and the coiling quality was improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 武汉钢铁有限公司
- Filing Date
- 2023-04-21
- Publication Date
- 2026-05-15
AI Technical Summary
In the current cold-rolled strip steel coiling process, improper tension control can easily lead to defects such as coiling scratches, loose coils, and coil collapses. In particular, the lack of detailed control for different specifications of products affects the coiling quality.
The coiling process is divided into an initial stage, a transition stage, and a tension steady-state stage. Different coiling tension control methods are adopted, including additional tension in the initial stage, tension reduction in the transition stage, and constant tension in the steady-state stage. The tension is adjusted according to factors such as the carbon content, strength, width, and thickness of the strip.
It improves winding quality, avoids defects such as loose winding, collapse winding and scratches, and ensures the winding stability and quality of products of different specifications.
Smart Images
Figure CN116673344B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of cold rolling production technology, and in particular to a method for controlling the coiling tension of cold-rolled strip steel. Background Technology
[0002] In steel production enterprises, cold-rolled products are generally produced by coiling steel strips into neat and compact coils for easy storage, transportation, and packaging. Typical delivery weights range from 6 to 20 tons, with inner coil diameters of Φ508mm or Φ610mm and outer coil diameters of Φ1100 to Φ2000mm. The coiling process is the final step in finished product manufacturing and is crucial for ensuring the quality of cold-rolled steel strips.
[0003] With intensifying competition in the steel industry, the specifications of strip steel products are becoming increasingly diverse. Existing cold-rolled steel products range in thickness from 0.22 to 1.6 mm and width from 800 to 1700 mm. Coupled with the low surface friction coefficient of cold-rolled steel, it is more prone to defects such as coiling scratches, loose coiling, and coil collapse due to improper tension selection compared to other coils. Thin steel strips have weak core support in their coils, making them susceptible to collapse during uncoiling or transportation, resulting in inability to be coiled in subsequent processes or generating a large amount of scrap. Excessive tension, on the other hand, easily causes scratches and coiling deformation. Furthermore, existing technologies are primarily designed for specific product types. While they calculate initial tension and control coiling tension in segments based on coiling length, they lack differentiation for different product specifications, and the tension is fixed, resulting in inadequate control over coiling quality. Summary of the Invention
[0004] The main objective of this invention is to provide a method for controlling the coiling tension of cold-rolled strip steel, which aims to select different coiling tensions according to different stages of coiling in order to improve the coiling quality.
[0005] To achieve the above objectives, the present invention provides a method for controlling the coiling tension of cold-rolled strip steel, comprising the following steps:
[0006] The coiling tension t is designed based on the required carbon content, strength, coil width, and coil thickness of the coiled strip.
[0007] Calculate the steady-state tension T0 based on the winding tension t;
[0008] Based on the coiling height, the coiling process is divided into an initial stage, a transition stage, and a tension steady-state stage. In the initial stage, the coiling tension is T1 = T0 × (1 + δ), where δ is the additional tension coefficient. In the transition stage, the coiling tension decreases from T1 to the steady-state tension T0. In the tension steady-state stage, the coiling tension is the steady-state tension T0. The coiling tension of the coiling machine is adjusted according to the three stages to obtain the steel coil.
[0009] Preferably, when the current height of the steel coil is between the start of coiling and the point where the coiled strip reaches the first preset height h1, the coiling tension T1 = T0 * (1 + δ) is controlled, where δ is the additional tension coefficient and T0 is the steady-state pressure.
[0010] When the current height of the steel coil is between the first preset height h1 and the second preset height h2, the coiling tension is controlled as T2 = T1 - (T1 - T0) × (h - h1) / (h2 - h1), where δ is the additional tension coefficient and h is the current coiling height of the steel coil.
[0011] When the current height of the steel coil is greater than the second preset height h2, control the coiling tension T3 = T0.
[0012] Preferably, the additional tension coefficient is between 0.1 and 0.5, depending on the condition of the cold rolling production line equipment.
[0013] Preferably, the steady-state tension T0 is calculated using the following formula:
[0014] T0 = t × W × h;
[0015] Where W is the strip width, h is the strip thickness, and t is the coiling tension.
[0016] Preferably, the winding tension is 21 N / mm. 2 ~35N / mm 2 .
[0017] Preferably, when classifying the coiling tension according to the carbon content and strength of the strip steel, the strip steel is divided into P steel, deep drawing mild steel, low alloy high strength steel, and high strength steel. According to the yield strength level, the higher the yield strength, the greater the coiling tension.
[0018] Preferably, when the winding tension is graded according to the thickness of the steel coil, the winding tension is negatively correlated with the thickness of the steel coil.
[0019] Preferably, during the strip winding process, the winding acceleration does not exceed 0.23 m / s². 2 .
[0020] This invention proposes a method for controlling the coiling tension of cold-rolled strip steel. Addressing the challenges of existing cold-rolling production lines producing a wide variety of products with significant variations in width and thickness, this method selects different coiling tensions for different products, employs a high-tension start-up, and maintains stable tension in the tension transition zone, thus ensuring coiling quality. This invention divides the coiling tension model into three stages: the initial additional tension zone, the transition stage during tension reduction, and the tension steady-state stage. It selects and controls the coiling tension based on the different strengths, widths, and thicknesses of cold-rolled products, including setting the unit coiling tension ratio, additional tension, and transition zone, ensuring coiling quality. Attached Figure Description
[0021] Figure 1 This is a flowchart illustrating the method for controlling the coiling tension of cold-rolled strip steel according to the present invention.
[0022] Figure 2 This is a diagram showing the change in coiling tension according to an embodiment of the method for controlling the coiling tension of cold-rolled strip steel according to the present invention;
[0023] Figure 3 This is a schematic diagram illustrating the change in coiling tension with height in one embodiment of the method for controlling the coiling tension of cold-rolled strip steel according to the present invention.
[0024] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0025] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
[0026] It should be noted that in the description of this invention, the terms "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0027] Reference Figure 1 This invention proposes a method for controlling the coiling tension of cold-rolled strip steel, comprising the following steps:
[0028] Step S10: Design the coiling tension t of the steel coil according to the required carbon content, strength, width and thickness of the coiled steel strip;
[0029] Step S20: Calculate the steady-state tension T0 based on the winding tension ratio t;
[0030] Step S30: According to the coiling height of the steel coil, the coiling process is divided into an initial stage, a transition stage, and a tension steady-state stage. In the initial stage, the coiling tension is T1 = T0 × (1 + δ), where δ is the additional tension coefficient. In the transition stage, the coiling tension decreases from T1 to the steady-state tension T0. In the tension steady-state stage, the coiling tension is the steady-state tension T0. The coiling tension of the coiling machine is adjusted according to the three stages to obtain the steel coil.
[0031] Step S30 specifically includes the following processes:
[0032] When the current height of the steel coil is between the start of coiling and the time when the coiled strip reaches the first preset height h1 (which can be selected as approximately 150mm), the coiling tension T1 = T0 * (1 + δ) is controlled, where δ is the additional tension coefficient and T0 is the steady-state pressure.
[0033] When the current height of the steel coil is between the first preset height h1 and the second preset height h2 (which can be selected as approximately 300mm), the coiling tension is controlled as follows: T = T1 - (T1 - T0) / (h2 - h1) × (h - h1), where δ is the additional tension coefficient and h is the current coiling height of the steel coil.
[0034] When the current height of the steel coil is greater than the second preset height h2, control the coiling tension T3 = T0.
[0035] An additional tension coefficient is applied, and its value is taken between 0.1 and 0.5 depending on the equipment condition of the cold rolling production line. The steady-state tension T0 is calculated using the following formula:
[0036] T0 = t × W × h;
[0037] Where W is the strip width, h is the strip thickness, and t is the coiling tension. Different coiling tensions are designed to suit different rolling mills, different product specifications, and even different raw material conditions.
[0038] Specifically, the winding tension is 21 N / mm. 2 ~35N / mm 2 .
[0039] When coiling tension is graded based on the carbon content and strength of the strip steel, the strip steel is classified into P-type steel, deep-drawing mild steel, low-alloy high-strength steel, and high-strength steel. According to the yield strength level, the higher the yield strength, the greater the coiling tension. When coiling tension is graded based on the coil thickness, the coiling tension is negatively correlated with the coil thickness.
[0040] Specifically, the process of selecting the winding tension ratio includes the following steps:
[0041] 1. Based on carbon content and strength, different steel grades are divided into four levels: S0, S1, S2, and S3, which correspond to ordinary P-type steel, deep-drawing mild steel, low-alloy high-strength steel, and high-strength steel, respectively. According to the yield strength level, the higher the yield strength, the greater the tensile strength per unit area. For example, the tensile strength per unit area of S1 is 26 MPa / mm². 2 s2 unit tension 28 MPa / mm 2 ;
[0042] 2. Classified according to the thickness of cold-rolled products: h≤0.5mm, 0.5mm<h≤0.6mm, 0.6mm<h≤0.7mm, 0.7mm<h≤0.85mm, 0.85mm<h≤1.0mm, h≥1.0mm;
[0043] 3. Classified according to the width of cold-rolled products: W < 900mm, 900mm ≤ W < 1000mm, 1000mm ≤ W < 1100mm, 1100mm ≤ W < 1200mm, 1200mm ≤ W < 1300mm, 1300mm ≤ W < 1400mm, 1400mm ≤ W < 1500mm, W ≥ 1500mm.
[0044] Based on empirical tests and calculations, the set values of coiling tension (unit tension) for different steel grades were obtained, as shown in Table 1 for the coiling tension of S1.
[0045] Table 1: Coiling Tension Ratio for S1 Steel Grades with Different Thicknesses and Widths
[0046]
[0047]
[0048] Using the winding tension ratio in Table 1 for production line winding tension control is more precise, basically eliminating defects such as loose winding and collapse winding that are easily caused by improper tension control, and winding scratches and abrasions caused by improper selection are also within the control range.
[0049] During the coiling process, the system acquires data on the thickness, strength, and other properties of the incoming strip. The program automatically determines and transmits the corresponding threading tension setpoint to the tension parameter variable. Based on the tension setpoint, internal adjustments are made to achieve the appropriate threading tension for the strip of the corresponding specifications. In this way, by controlling the threading tension of the coiler, the tension variation in the transition zone, and the steady-state tension value, coiling defects caused by improper threading tension are effectively avoided.
[0050] During the strip coiling process, the coiling acceleration shall not exceed 0.23 m / s². 2 In the starting and braking processes of an electric drive system, the driving torque must overcome both the load torque and the accelerating torque. For a coiler, to maintain a constant tension in the strip, the effect of the accelerating torque on the tension must be eliminated. Therefore, the accelerating torque must be calculated and used as part of the total torque setpoint to control the torque, thus achieving constant tension control.
[0051] Reference Figure 2 and Figure 3 The following description uses a specific embodiment as an example.
[0052] The coiler has a drum diameter of Φ610mm, a strip steel specification of 0.6mm×1250mm, a steel grade of DC01, and a coil outer diameter of Φ1250mm.
[0053] From the start of winding until the roll diameter reaches Φ910mm, control the unit winding tension at 25N / mm. 2 ×1.3=32.5N / mm 2 ,
[0054] When the diameter of the coiled steel strip is between Φ910mm and Φ1150mm, the coiling tension is controlled and adjusted according to the formula T2=T1-(T1-T0)×(h-h1) / (h2-h1) so that the coiling tension gradually decreases from T1 to T0.
[0055] When the diameter of the steel coil exceeds Φ1150mm, the unit winding tension setting is 25N / mm. 2 Continue winding until the end of production.
[0056] After threading is complete, the winding speed is set at a maximum acceleration of 0.23 m / s². 2 Increase the speed to 350 m / min, then gradually decrease the tension to T1 (32.5 N / mm). 2 Run at this speed until the roll diameter reaches Φ910mm, then wind at the normal speed until the end of production.
[0057] This invention proposes a method for controlling the coiling tension of cold-rolled strip steel. Addressing the challenges of existing cold-rolling production lines producing a wide variety of products with significant variations in width and thickness, this method selects different coiling tensions for different products, employs a high-tension start-up, and maintains stable tension in the tension transition zone, thus ensuring coiling quality. This invention divides the coiling tension model into three stages: the initial additional tension zone, the transition stage during tension reduction, and the tension steady-state stage. It selects and controls the coiling tension based on the different strengths, widths, and thicknesses of cold-rolled products, including setting the unit coiling tension ratio, additional tension, and transition zone, ensuring coiling quality.
[0058] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.
Claims
1. A method for controlling the coiling tension of cold-rolled strip steel, characterized in that, Includes the following steps: The coiling tension t is designed based on the required carbon content, strength, coil width, and coil thickness of the coiled strip. Calculate the steady-state tension T0 based on the winding tension t; Based on the coiling height, the coiling process is divided into an initial stage, a transition stage, and a tension steady-state stage. In the initial stage, the coiling tension is T1 = T0 * (1 + δ), where δ is the additional tension coefficient. In the transition stage, the coiling tension decreases from T1 to the steady-state tension T0. In the tension steady-state stage, the coiling tension is the steady-state tension T0. The coiling tension of the coiling machine is adjusted according to these three stages to obtain the steel coil. The additional tension coefficient is taken as between 0.3 and 0.5 based on the equipment conditions of the cold rolling production line. During the coiling process of the strip steel, the coiling acceleration does not exceed 0.23 m / s². 2 ; When the coiling tension is graded according to the carbon content and strength of the strip steel, the strip steel is divided into P steel, deep drawing mild steel, low alloy high strength steel and high strength steel. According to the yield strength level, the higher the yield strength, the greater the coiling tension. When the coiling tension is graded according to the width and thickness of the steel coil, the coiling tension is negatively correlated with the width and thickness of the steel coil.
2. The method for controlling the coiling tension of cold-rolled strip steel as described in claim 1, characterized in that, When the current height of the steel coil is between the start of coiling and the first preset height h1 of the coiled strip, the coiling tension is controlled as T1 = T0 × (1 + δ), where δ is the additional tension coefficient and T0 is the steady-state pressure. When the current height of the steel coil is between the first preset height h1 and the second preset height h2, the coiling tension is controlled as T1-(T1-T0)×(h-h1) / (h2-h1), where δ is the additional tension coefficient and h is the current coiling height of the steel coil. When the current height of the steel coil is greater than the second preset height h2, control the coiling tension T3 = T0.
3. The method for controlling the coiling tension of cold-rolled strip steel as described in claim 1, characterized in that, The steady-state tension T0 is calculated using the following formula: T0 = t × W × h; Where W is the strip width, h is the strip thickness, and t is the coiling tension.
4. The method for controlling the coiling tension of cold-rolled strip steel as described in claim 1, characterized in that, The winding tension is 21 N / mm. 2 ~35N / mm 2 .