Method for eliminating black line in short-process production of magnetic yoke steel

Abstract

This invention belongs to the field of steel production technology and discloses a method for eliminating black lines during the coiling of magnetic yoke steel in short-process production, including: 1) control of the finishing mill work rolls, controlling the rolling amount of the work rolls to ≤1200 tons and the local high point of the strip to ≤12μm; 2) control of the unit coiling tension, controlling the unit coiling tension to 20~30N / mm. 2 3) Gradual control of winding tension, including the head threading tension stage, the coil tension stage, the tension reduction stage, and the tail tension stage; 4) Winding tension distribution control, controlling the tension distribution between the pinch rolls and the drum to be 25~35%; 5) Leveler unwinding process control, controlling the unwinding speed to be 30~50 m / min, the single-sided pressure of the work roll to be 15~23 kN; the initial value of the unwinding unit tension is 8~12 N / mm. 2 As the unwinding length increases, the change is 0.3~0.8 N / mm. 2 The rate of increase in m is increased to the target value of 20~22 N / mm. 2 This invention solves the problem of winding black wire in the short-process production of DCR600 magnetic yoke steel, and realizes the high-quality, high-stability large-scale production of magnetic yoke steel in a short process.

Description

Technical Field

[0001] This invention belongs to the field of steel production technology, and specifically relates to a method for eliminating the black wire in the winding of magnetic yoke steel during short-process production. Background Technology

[0002] During the rolling of magnetic yoke steel on the CSP finishing mill, various factors such as unreasonable rolling schedule arrangement, roll wear, and mill leakage can create local high points on the strip cross-section. These local high points transform the originally uniform interlayer contact into localized line contact or even point contact between the high point and the upper or lower strip layers, drastically reducing the contact area. This results in a doubling of the actual contact stress in that area, far exceeding that of the surrounding area. Simultaneously, the coiling of magnetic yoke steel requires a reasonable coiling tension to ensure tight coiling and prevent defects such as flattened coils or misaligned layers. However, in the aforementioned local high point areas, during high-tension coiling, the radial pressure of the coil increases with the coiling diameter. Under this pressure, the iron oxide scale on the surfaces of the upper and lower strip layers is pressed tightly together, undergoing elastic or plastic deformation, resulting in a tighter interlocking, and potentially even microscopic mechanical interlocking or "cold welding." During the subsequent uncoiling process, areas with severe iron oxide scale adhesion may tear, forming black lines. These black lines affect the product's appearance, leading to downgrading and reclassification. Further processing and manufacturing by downstream users will also expose the problem, impacting the final product's surface quality and mechanical properties. Therefore, resolving the black line problem on the surface of magnetic yoke steel is a pressing technical challenge in this field. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address the shortcomings of the existing technology by providing a method for eliminating the black wire winding of magnetic yoke steel in short-process production, so as to solve the quality defect of black wire winding on the surface of magnetic yoke steel, improve the surface quality, and thus realize the high-quality, high-stability large-scale production of magnetic yoke steel in short-process production.

[0004] To address the technical problem proposed in this invention, this invention provides a method for eliminating black lines during the winding of magnetic yoke steel in short-process production, including control of the finishing mill work roll, control of unit winding tension, control of winding tension step control, control of winding tension distribution, and control of the leveling machine unwinding process.

[0005] In the above scheme, the magnetic yoke steel is DCR600 with a thickness of 2~3mm.

[0006] In the above scheme, the control of the finishing work roll includes controlling the rolling amount of the work roll to be ≤1200 tons, the local high point of the strip to be ≤12μm, and replacing the work roll when it exceeds the limit.

[0007] Furthermore, when the finished strip thickness is 2.0 ≤ 2.5 mm, the rolling amount of the work roll is ≤ 1000 tons, and the local high point of the strip is ≤ 12 μm.

[0008] Furthermore, when the finished strip thickness is 2.5 < 3.0 mm, the rolling amount of the work roll is ≤ 1200 tons, and the local high point of the strip is ≤ 10 μm.

[0009] In the above scheme, the unit winding tension is controlled at 20~30N / mm. 2 .

[0010] Furthermore, when the strip thickness is 2.0 ≤ strip thickness ≤ 2.5 mm, the unit coiling tension is 26~30 N / mm. 2 .

[0011] Furthermore, when 2.5 < strip thickness ≤ 3.0 mm, the unit coiling tension is 20~25 N / mm. 2 .

[0012] In the above scheme, the winding tension step control includes the head threading tension stage, the coil tension stage, the tension reduction stage, and the tail tension stage.

[0013] Furthermore, the head threading tension stage begins when the strip exits the finishing mill stand and ends when the coil is tensioned; the preset target value of the coil tension in this stage is the head threading tension, which is 100-120% of the unit winding tension.

[0014] Furthermore, when the strip thickness is 2.0 ≤ strip thickness < 2.5 mm, the head threading tension is 110~120% of the unit winding tension.

[0015] Furthermore, when the strip thickness is 2.5 ≤ strip thickness < 2.8 mm, the head threading tension is 105~110% of the unit winding tension.

[0016] Furthermore, when the strip thickness is 2.8 ≤ strip thickness ≤ 3.0 mm, the head threading tension is 100~105% of the unit winding tension.

[0017] Furthermore, the coil tension stage begins after the coil is tensioned and ends when the calculated diameter of the coil reaches the constant tension conversion diameter; this stage is the constant tension stage, in which the coiling tension is the unit coiling tension and the constant tension conversion diameter is 1000~1200mm.

[0018] Furthermore, when the strip thickness is 2.0 ≤ strip thickness < 2.5 mm, the constant tension conversion diameter is 1170~1200 mm.

[0019] Furthermore, when the strip thickness is 2.5 ≤ strip thickness < 2.8 mm, the constant tension conversion diameter is 1080~1120 mm.

[0020] Furthermore, when the strip thickness is 2.8 ≤ strip thickness ≤ 3.0 mm, the constant tension conversion diameter is 1000~1030 mm.

[0021] Furthermore, the tension reduction stage begins when the calculated diameter of the steel coil reaches the constant tension conversion diameter and ends when the steel is ejected at F1 of the finishing mill; this stage is the constant torque stage, in which the coiling tension decreases as the coil diameter increases, while keeping the torque constant, and the torque = 0.5 × constant tension conversion diameter × unit coiling tension × strip cross-sectional area.

[0022] Furthermore, the tail tension stage begins when the steel is thrown out at F1 of the finishing mill and ends when the steel coil is fully wound; this stage uses a fixed tail unit tension value of 10~12 N / mm. 2 The purpose is to reduce the total tension at the tail and improve the curl shape.

[0023] In the above scheme, the tension distribution control between the pinch roller and the drum (the percentage of tension between the pinch roller and the drum to the total winding tension) is 25-35%.

[0024] Furthermore, when the strip thickness is 2.0 ≤ strip thickness < 2.5 mm, the tension distribution between the pinch roll and the drum is 33~35%.

[0025] Furthermore, when the strip thickness is 2.5 ≤ strip thickness < 2.8 mm, the tension distribution between the pinch roll and the drum is 28~32%.

[0026] Furthermore, when the strip thickness is 2.8 ≤ strip thickness ≤ 3.0 mm, the tension distribution between the pinch roll and the drum is 25~27%.

[0027] In the above scheme, the unwinding speed of the leveling machine is controlled at 30~50 m / min, and the pressure on one side of the work roll is 15~23 kN to achieve light pressing.

[0028] In the above scheme, the initial value of the unwinding unit tension during the leveling machine unwinding process is 8~12 N / mm. 2 As the unwinding length increases, the change is 0.3~0.8 N / mm. 2 The rate of increase in m is increased to the target value of 20~22 N / mm. 2 .

[0029] Furthermore, when the strip thickness is 2.0 ≤ strip thickness ≤ 2.5 mm, the uncoiling speed is 30~40 m / min, the single-sided pressure of the work roll is 15~18 kN, and the initial value of the uncoiling unit tension is 8~10 N / mm. 2 The growth rate is 0.3~0.5 N / mm 2 ·m.

[0030] Furthermore, when the strip thickness is 2.5 < 3.0 mm, the uncoiling speed is 40~50 m / min, the single-sided pressure of the work roll is 20~23 kN, and the initial value of the uncoiling unit tension is 10~12 N / mm.2 The growth rate is 0.6~0.8 N / mm 2 ·m.

[0031] The role and mechanism of the main processes in this invention: The reason this invention controls uneven wear of the finishing work rolls is that uneven wear of the rolls often results in severe wear at the roll positions corresponding to the strip edges, forming wear grooves. This uneven wear directly leads to uneven roll gaps, causing localized high points in the subsequently rolled strip at the locations of uneven wear. This creates stress superposition, and during uncoiling in subsequent processes, the high-point areas are forcibly separated. The iron oxide scale, already damaged, broken, and adhered under high stress, is torn apart along both sides of the high point under the peeling force, ultimately appearing as black lines. Therefore, the rolling weight of the work rolls is controlled to ≤1200 tons, and the localized high point of the strip is controlled to ≤12μm. If these limits are exceeded, the work rolls are replaced. Furthermore, for 2.0~2.5mm strip steel, a local high point of 12μm corresponds to approximately 0.5% of the strip steel thickness, resulting in greater interlayer stress during coiling. Therefore, the rolling amount needs to be more strictly controlled to avoid exacerbating wear on the rolls and aggravating the high point. For 2.5~3.0mm strip steel, a local high point of 10μm corresponds to 0.3~0.4% of the thickness, with a smaller impact compared to thinner specifications. Production practice has also shown that it is feasible to appropriately relax the rolling amount requirements, taking into account production efficiency.

[0032] The reason this invention controls the unit tension during coiling is that excessive coiling tension increases the radial pressure on the steel coil. Under this immense pressure, the iron oxide scale on the surfaces of the upper and lower strips is tightly pressed together, potentially leading to elastoplastic deformation or even microscopic "cold welding." During the subsequent uncoiling process, the iron oxide scale is peeled off the strip surface, forming black lines. The magnetic yoke steel DCR600 itself has a high yield strength. For thin sections of 2.0~3.0mm, conventional coiling processes typically employ high-tension coiling, with a unit tension generally ranging from 36~50 N / mm. 2 This is to ensure the coil shape is normal and that flattening does not occur. However, through production practice, high-tension winding can cause black lines on the surface, so the unit tension needs to be reduced, and therefore controlled at 20~30N / mm. 2 Different thicknesses require different optimal unit tensions; too high a tension will result in black line defects, while too low a tension may result in flattened roll defects.

[0033] The reason this invention employs different winding tension step controls is to adjust the tension appropriately based on different thicknesses, ensuring that coil shape abnormalities such as flattening and misalignment are avoided, while simultaneously preventing excessive radial pressure on the steel coil. Thinner strips require greater unit tension and a longer overall constant tension process, while thicker strips require the opposite. Simultaneously, the constant tension process must not be too high; otherwise, the overall tension during winding will be too high, resulting in a shorter duration of the subsequent tension reduction phase, which is detrimental to interlayer pressure and the formation of black lines. Conventional winding processes involve constant tension and high tension winding. This solution replaces this with staged tension reduction control, primarily controlling the length of the constant tension phase. For 2.0~2.5mm thin strips, threading is difficult, requiring 110~120% high tension to ensure the inner coil does not collapse. A longer constant tension phase also prevents premature tension reduction, which can cause loosening and lifting of the coil at the mid-to-tail. For 2.5~2.8mm thick strips, threading is correspondingly less difficult, allowing for a reduction in threading tension and a shorter constant tension phase, thus reducing the duration of high tension and interlayer pressure. Thicker strip steel (2.8~3.0mm) is less prone to inner ring collapse. Reducing the diameter during the threading tension and constant tension transition can shorten the high tension stage to the greatest extent, thus inhibiting the cold welding of iron oxide scale from the coiling source.

[0034] The reason this invention controls tension distribution is that the DCR600 magnetic yoke steel itself has high strength, and compared to other steel grades of the same thickness, the unit tension setting is relatively small, which may lead to some coil shape defects during the winding process. Considering both the incoming material waviness and the high strength of the strip itself, different tension distributions are needed to offset the impact of small unit tension, ensuring acceptable coil shape and not affecting the generation of black lines. Therefore, the tension distribution between the pinch rolls and the drum is controlled at 25-35%. The essence of tension distribution is the proportion of tension from the pinch rolls to the drum, which determines the force distribution on the strip during winding. The higher the proportion, the greater the traction force of the pinch rolls on the strip, and the smaller the interlayer radial pressure. For 2.0-2.5mm strip, interlayer slippage is prone to occur during winding, requiring a relatively high pinch roll proportion. Through the active traction of the pinch rolls, the interlayer pressure of the drum on the strip is reduced. For 2.5-2.8mm strip, a moderate tension distribution is selected to balance coil shape and pinch roll traction effect. 2.8~3.0mm reduces the pressure of the pinch rolls on the strip, avoiding the potential for localized high points caused by uneven wear of the pinch rolls.

[0035] The reason this invention controls the uncoiling process of the leveling machine is to form a full-process tension matching system with the aforementioned unit tension and constant tension conversion diameter control in the winding stage: In the winding stage, differentiated tension control reduces interlayer adhesion of iron oxide scale; in the leveling and uncoiling stage, low-tension gradual control prevents the adhesion area from tearing into black lines, achieving a dual effect of "source control + end-of-line avoidance." This solves the industry's technical blind spot where existing technologies only focus on winding and neglect the amplification of black lines in the uncoiling process. Specifically: 1) Controlling the initial uncoiling unit tension: This avoids the forced tearing of the iron oxide scale adhesion area between steel coil layers during conventional high-tension uncoiling, preventing the appearance and expansion of black line defects from the uncoiling end. Simultaneously, it matches the high-strength characteristics of DCR600 to prevent strip deviance and waviness during uncoiling. The yield strength of magnetic yoke steel DCR600 is ≥600MPa, far exceeding that of conventional hot-rolled steel grades. If the uncoiling tension is lower than 8N / mm... 2 The rigidity of the strip itself can easily cause uncoiling deviation and interlayer misalignment; exceeding 12 N / mm 2 This would directly tear the area where the iron oxide scale is bonded, therefore the setting is 8~12 N / mm. 2 Furthermore, the initial uncoiling unit tension for graded design is as follows: For thin strip steel with a stiffness of 2.0~2.5mm, if the initial uncoiling tension is too high, plastic deformation and waviness of the strip steel are likely to occur. (8~10 N / mm) 2 To balance the critical values ​​of "low-tension tear resistance" and "deformation resistance," 2.5~3.0mm thick strip steel is used to increase rigidity, allowing it to withstand slightly higher initial tension (10~12N / mm). 2 (This ensures efficient unbooking)

[0036] 2) Gradual tension control: using 0.3~0.8 N / mm 2 • Gradual tension control avoids sudden increases in interlayer stress caused by instantaneous tension changes, allowing the slightly adhered iron oxide scale to separate naturally rather than being violently torn, fundamentally reducing the formation of black lines. During the winding stage, 2.0~2.5mm thin strip steel uses a higher winding tension, and the interlayer iron oxide scale adhesion is slightly higher than that of thicker strip steel. Therefore, the initial unwinding tension can be lower and the gradual change rate can be slower (0.3~0.5N / mm). 2 •m), allowing for more natural separation time in the occlusal area; thicker strip steel has lower coiling tension and a lighter degree of occlusion, allowing for a more appropriate increase in the gradient rate (0.6~0.8N / mm). 2 (m), balancing quality and production efficiency.

[0037] 3) Control the working roll pressure: Implement a light pressure of 15~23 kN to reduce mechanical crushing of the strip surface during uncoiling and prevent iron oxide scale at local high points from being pressed into the strip matrix; thin strip has low rigidity and can use a low pressure of 15~18 kN to avoid the working roll from creating new local high points; thick strip has high rigidity and requires a slightly higher pressure of 20~23 kN to ensure smooth strip traction and prevent slippage.

[0038] 4) Control the uncoiling speed: Control the uncoiling speed to 30~50 m / min. Thin strip steel is prone to slippage under low tension, and a low speed of 30~40 m / min can improve operational stability; for thick strip steel with high rigidity, the speed can be increased to 40~50 m / min to avoid excessive reduction in production efficiency.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention solves the problem of black wire coiling in the short-process production of DCR600 magnetic yoke steel by controlling the finishing work rolls, unit coiling tension, coiling tension step control, coiling tension distribution control, and leveling machine uncoiling process control, thus achieving high-quality, high-stability, and large-scale production of magnetic yoke steel in a short process. This method requires no equipment modification during implementation; existing equipment and controls can be used, making it simple, easy to operate, and highly practical. Attached Figure Description

[0040] Figure 1 This is a display image showing the black lines on the surface of the DCR600 magnetic yoke steel produced as a comparative example. Detailed Implementation

[0041] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0042] The following embodiments employ methods to eliminate the black wire winding process in the short-process production of magnetic yoke steel, including the following control measures: 1) Finishing mill work roll control The rolling amount of the work rolls is controlled to be ≤1200 tons, the local high point of the strip is ≤12μm, and different requirements are set for strips of different thicknesses: When the finished strip thickness is 2.0 ≤ 2.5 mm, the rolling amount of the work roll is ≤ 1000 tons, and the local high point of the strip is ≤ 12 μm; 2.5 When the finished strip thickness is less than or equal to 3.0 mm, the rolling amount of the work roll is less than or equal to 1200 tons, and the local high point of the strip is less than or equal to 10 μm. 2) Unit winding tension control Unit winding tension controlled at 20~30N / mm 2 Different unit winding tensions are set for strips of different thicknesses: When the strip thickness is 2.0 ≤ strip thickness ≤ 2.5 mm, the unit coiling tension is 26~30 N / mm. 2 ; 2.5 < strip thickness ≤ 3.0 mm, the unit coiling tension is 20~25 N / mm 2 ; 3) Winding tension step control This includes the head tensioning stage, the coil tensioning stage, the tension reduction stage, and the tail tensioning stage. The head threading tension stage begins when the strip exits the finishing mill stand and ends when the coil is fully tensioned. During this stage, the head threading tension is 100-120% of the unit coiling tension, and different head threading tensions are set for strips of different thicknesses. When the strip thickness is 2.0 ≤ strip thickness < 2.5 mm, the threading tension at the head should be 110~120% of the unit winding tension; When the strip thickness is 2.5 ≤ strip thickness < 2.8 mm, the threading tension at the head should be 105~110% of the unit winding tension; When the strip thickness is ≤3.0mm, the tension at the head of the strip should be 100-105% of the unit winding tension. The coil tension stage begins after the coil is fully tensioned and ends when the calculated diameter of the coil reaches the constant tension conversion diameter. During this stage, the coiling tension is the unit coiling tension, and the constant tension conversion diameter is 1000~1200mm. Different constant tension conversion diameters are set for different thicknesses of strip steel. When the strip thickness is 2.0 ≤ strip thickness < 2.5 mm, the constant tension conversion diameter is 1170~1200 mm; When the strip thickness is 2.5 ≤ strip thickness < 2.8 mm, the constant tension conversion diameter is 1080~1120 mm; When the strip thickness is ≤ 3.0 mm, the constant tension conversion diameter is 1000~1030 mm; The tension reduction stage begins when the calculated diameter of the steel coil reaches the constant tension conversion diameter and ends when the steel is ejected at F1 of the finishing mill. During this stage, the coiling tension decreases as the coil diameter increases, while the torque remains constant. Torque = 0.5 × constant tension conversion diameter × unit coiling tension × strip cross-sectional area. The tail tension stage begins when the steel is thrown out at F1 of the finishing mill and ends when the coil is fully wound; this stage uses a fixed tail unit tension value of 10~12 N / mm. 2 ; 4) Winding tension distribution control The tension distribution between the pinch rolls and the drum is controlled at 25-35%, and different tension distributions are set for strips of different thicknesses: When the strip thickness is 2.0 ≤ strip thickness < 2.5 mm, the tension distribution between the pinch rolls and the drum is 33~35%; When the strip thickness is 2.5 ≤ strip thickness < 2.8 mm, the tension distribution between the pinch rolls and the drum is 28~32%; When the strip thickness is 2.8 ≤ strip thickness ≤ 3.0 mm, the tension distribution between the pinch rolls and the drum is 25~27%; 5) Leveling machine uncoiling process control Control the unwinding speed to 30~50 m / min, and the single-sided pressure of the work roll to 15~23 kN; the initial value of the unwinding unit tension is 8~12 N / mm. 2 As the unwinding length increases, the change is 0.3~0.8 N / mm. 2 The rate of increase in m is increased to the target value of 20~22 N / mm. 2 Different controls are applied to strips of different thicknesses: When the strip thickness is 2.0 ≤ strip thickness ≤ 2.5 mm, the uncoiling speed is 30~40 m / min, the single-sided pressure of the work roll is 15~18 kN, and the initial value of the uncoiling unit tension is 8~10 N / mm. 2 The growth rate is 0.3~0.5 N / mm 2 ·m; 2.5 < strip thickness ≤ 3.0 mm, the uncoiling speed is 40~50 m / min, the single-sided pressure of the work roll is 20~23 kN, and the initial value of the uncoiling unit tension is 10~12 N / mm. 2 The growth rate is 0.6~0.8 N / mm 2 ·m.

[0043] Example 1 and Comparative Example 1 The following control parameters are used to produce DCR600 magnetic yoke steel with a thickness of 2.0mm and a width of 1200mm:

[0044] Production Results: Example 1 produced 48 rolls, none of which had black threads during winding. Comparative Example 1 produced 10 rolls, with 7 rolls exhibiting black threads during winding.

[0045] Example 2 and Comparative Example 2 The following control parameters are used to produce DCR600 magnetic yoke steel with a thickness of 2.5mm and a width of 1200mm:

[0046] Production Results: Example 2 produced 26 rolls, none of which had black threads during winding. Comparative Example 2 produced 7 rolls, with 5 rolls exhibiting black threads during winding.

[0047] Example 3 and Comparative Example 3 The following control parameters are used to produce DCR600 magnetic yoke steel with a thickness of 3.0mm and a width of 1245mm:

[0048] Production Results: Example 3 produced 15 rolls, none of which had black threads during winding. Comparative Example 3 produced 5 rolls, with 3 rolls exhibiting black threads during winding.

[0049] The above embodiments are merely examples for clear illustration and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations, and any obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for eliminating the black wire winding process in the short-process production of magnetic yoke steel, characterized in that, Including the following control measures: 1) Finishing mill work roll control The rolling amount of the work rolls should be controlled to be ≤1200 tons, and the local high point of the strip should be ≤12μm; 2) Unit winding tension control Unit winding tension controlled at 20~30N / mm 2 ; 3) Winding tension step control This includes the head tensioning stage, the coil tensioning stage, the tension reduction stage, and the tail tensioning stage. The head threading tension stage begins when the strip exits the finishing mill stand and ends when the coil is fully tensioned; the head threading tension during this stage is 100-120% of the unit coiling tension. The coil tension stage begins after the coil is fully tensioned and ends when the calculated diameter of the coil reaches the constant tension conversion diameter. During this stage, the coiling tension is the unit coiling tension, and the constant tension conversion diameter is 1000~1200mm. 4) Winding tension distribution control The tension distribution between the pinch rollers and the drum is controlled to be 25-35%; 5) Leveling machine uncoiling process control Control the unwinding speed to 30~50 m / min, and the single-sided pressure of the work roll to 15~23 kN; the initial value of the unwinding unit tension is 8~12 N / mm. 2 As the unwinding length increases, the change is 0.3~0.8 N / mm. 2 The rate of increase in m is increased to the target value of 20~22 N / mm. 2 .

2. The method for eliminating the black wire winding in the short-process production of magnetic yoke steel according to claim 1, characterized in that, In step 1), different requirements are set for strip steel of different thicknesses: when the finished strip steel thickness is 2.0 ≤ 2.5 mm, the rolling amount of the work roll is ≤ 1000 tons, and the local high point of the strip steel is ≤ 12 μm; when the finished strip steel thickness is 2.5 < 3.0 mm, the rolling amount of the work roll is ≤ 1200 tons, and the local high point of the strip steel is ≤ 10 μm.

3. The method for eliminating the black wire winding in the short-process production of magnetic yoke steel according to claim 1, characterized in that, In step 2), different unit winding tensions are set for strips of different thicknesses: when 2.0 ≤ strip thickness ≤ 2.5 mm, the unit winding tension is 26~30 N / mm. 2 2.5 < strip thickness ≤ 3.0 mm, the unit coiling tension is 20~25 N / mm. 2 .

4. The method for eliminating the black wire winding in the short-process production of magnetic yoke steel according to claim 1, characterized in that, In step 3), different head threading tensions are set for strips of different thicknesses: when 2.0 ≤ strip thickness < 2.5 mm, the head threading tension is 110~120% of the unit winding tension; when 2.5 ≤ strip thickness < 2.8 mm, the head threading tension is 105~110% of the unit winding tension; when 2.8 ≤ strip thickness ≤ 3.0 mm, the head threading tension is 100~105% of the unit winding tension.

5. The method for eliminating the black wire winding process in the short-process production of magnetic yoke steel according to claim 1, characterized in that, In step 3), different constant tension conversion diameters are set for strips of different thicknesses: when 2.0 ≤ strip thickness < 2.5 mm, the constant tension conversion diameter is 1170~1200 mm; when 2.5 ≤ strip thickness < 2.8 mm, the constant tension conversion diameter is 1080~1120 mm; when 2.8 ≤ strip thickness ≤ 3.0 mm, the constant tension conversion diameter is 1000~1030 mm.

6. The method for eliminating the black wire winding in the short-process production of magnetic yoke steel according to claim 1, characterized in that, The tension reduction stage begins when the calculated diameter of the steel coil reaches the constant tension conversion diameter and ends when the steel is ejected at F1 of the finishing mill. During this stage, the coiling tension decreases as the coil diameter increases, while the torque remains constant. The torque is calculated as 0.5 × constant tension conversion diameter × unit coiling tension × strip cross-sectional area.

7. The method for eliminating the black wire winding in the short-process production of magnetic yoke steel according to claim 1, characterized in that, The tail tension stage begins when the steel is thrown out at F1 of the finishing mill and ends when the steel coil is coiled; this stage uses a fixed tail unit tension value of 10~12 N / mm. 2 .

8. The method for eliminating the black wire winding in the short-process production of magnetic yoke steel according to claim 1, characterized in that, In step 4), different tension distributions are set for strips of different thicknesses: when the strip thickness is 2.0 ≤ strip thickness < 2.5 mm, the tension distribution between the pinch roll and the drum is 33~35%; when the strip thickness is 2.5 ≤ strip thickness < 2.8 mm, the tension distribution between the pinch roll and the drum is 28~32%; when the strip thickness is 2.8 ≤ strip thickness ≤ 3.0 mm, the tension distribution between the pinch roll and the drum is 25~27%.

9. The method for eliminating the black wire winding in the short-process production of magnetic yoke steel according to claim 1, characterized in that, In step 5), different controls are applied for strips of different thicknesses: when the strip thickness is 2.0 ≤ 2.5 mm, the uncoiling speed is 30~40 m / min, the single-sided pressure of the work roll is 15~18 kN, and the initial value of the uncoiling unit tension is 8~10 N / mm. 2 The growth rate is 0.3~0.5 N / mm 2 When the strip thickness is 2.5 < 3.0 mm, the uncoiling speed is 40~50 m / min, the single-sided pressure of the work roll is 20~23 kN, and the initial value of the uncoiling unit tension is 10~12 N / mm. 2 The growth rate is 0.6~0.8 N / mm 2 ·m.

10. The method for eliminating the black wire winding in the short-process production of magnetic yoke steel according to claim 1, characterized in that, The magnetic yoke steel is DCR600 with a thickness of 2~3mm.

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