Method for improving low-grade non-oriented silicon steel edge rib

Abstract

The invention discloses a method for improving low-grade non-oriented silicon steel edge ribs, which is characterized by comprising the following steps: rolling at the temperature of 1030-870 DEG C with the rolling thickness of 2.7-2.9 mm and the coiling temperature of 730 + / -15 DEG C; the convexity and wedge shape control in the hot rolling process must follow the principle that the wedge shape is smaller than the convexity, the wedge shape is controlled according to-10-10 microns, and the convexity is controlled according to 25 + / -10 microns; and 5, a rack acid continuous rolling procedure: S1, rolling according to a flat roll, S2, rolling according to a conical roll, and rolling according to flat rolls for other roll types. After the method for improving the non-oriented silicon steel edge rib is adopted, the size precision, the structure uniformity, the magnetic performance and the like are remarkably improved, specifically, in the aspect of the size precision, the height of the optimized edge rib is smaller than 0.2 mm, the edge rib is free of wave-shaped defects after being uncoiled, and the geometric consistency of a product is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical materials technology, and particularly relates to a method for improving the edge reinforcement of low-grade non-oriented silicon steel. Background Technology

[0002] Currently, patent application number 202311213767.8 discloses a method for controlling edge rib formation in non-oriented silicon steel and the resulting non-oriented silicon steel, focusing on controlling the composition and rolling temperature of the non-oriented silicon steel to avoid edge rib formation. This invention emphasizes requirements for crown, wedge shape control and their corresponding relationships, as well as the design and arrangement of acid-concentrated rolls, in addition to temperature control. Based on the design scheme, the problem of edge rib formation in low-grade non-oriented silicon steel is solved, and the difference between grades within the same sheet is kept at a low level.

[0003] Non-oriented silicon steel, a core material in the electrical industry, is widely used in the manufacture of equipment such as motors and transformers. Its performance directly affects the power conversion efficiency and the operational stability of the equipment. However, the prevalent edge rib problem in the current production process of non-oriented silicon steel seriously restricts the improvement of product quality. Edge rib defects not only lead to a decrease in the dimensional accuracy of silicon steel sheets, but may also cause a series of negative effects such as uneven magnetic properties and increased processing difficulty, thus failing to meet the market demand for high-quality silicon steel products. Summary of the Invention

[0004] The purpose of this invention is to provide an effective method for improving the edge reinforcement of non-oriented silicon steel, so as to solve many problems existing in the existing technology and production process, thereby significantly improving the overall performance of silicon steel.

[0005] This invention proposes a systematic solution by optimizing raw material selection, precisely controlling production process parameters, and improving heat treatment processes.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] This invention discloses a method for improving the edge reinforcement of low-grade non-oriented silicon steel, comprising:

[0008] Rolling is carried out at a temperature between 1030℃ and 870℃, with a rolling thickness of 2.7 to 2.9 mm and a coiling temperature of 730±15℃.

[0009] In the hot rolling process, the control of crown and wedge shape must follow the principle that the wedge shape is smaller than the crown shape, with the wedge shape controlled at -10 to 10 μm and the crown shape controlled at 25 ± 10 μm.

[0010] 5. Continuous acid rolling process: S1 roll type is rolled as flat roll, S2 as tapered roll, and other roll types are rolled as flat roll.

[0011] Furthermore, the chemical composition of the low-grade non-oriented silicon steel edge reinforcement by mass percentage is as follows: C: ≤0.0030%, Si: 0.25~0.35%, Mn: 0.25~0.35%, P: 0.050~0.065%, S: ≤0.004%, Als: 0.25~0.40%, N: ≤0.0020%, O≤0.0015%, Ti: ≤0.0025%, with the remainder being Fe and unavoidable impurities, totaling 100% by mass.

[0012] Furthermore, the chemical composition of the low-grade non-oriented silicon steel edge reinforcement by mass percentage is as follows: C: 0.0030%, Si: 0.33%, Mn: 0.28%, P: 0.062%, S: 0.003%, Als: 0.36%, N: 0.0017%, O: 0.0012%, Ti: 0.0023%, with the remainder being Fe and unavoidable impurities.

[0013] Furthermore, the hot-rolled exit temperature is <1030℃, and after 7 consecutive rolling, it is rolled to 2.75mm, with a final rolling temperature of 878℃, a coiling temperature of 745℃, a wedge shape of 8μm, and a crown of 17μm.

[0014] In the acid continuous rolling mill, S1 is a flat roll, S2 is a tapered roll, and the others are flat rolls; a bending roll and shifting roll system is implemented, and the rolling forces are as follows:

[0015]

[0016] After annealing, unwind the coil to check for edge waviness and edge ridges. After coiling, use a bulging gauge to inspect.

[0017] Furthermore, the chemical composition of the low-grade non-oriented silicon steel edge reinforcement by mass percentage is as follows: C: 0.0025%, Si: 0.31%, Mn: 0.28%, P: 0.058%, S: 0.003%, Als: 0.32%, N: 0.0018%, O: 0.0009%, Ti: 0.0024%, with the remainder being Fe and unavoidable impurities.

[0018] Furthermore, the hot-rolled exit temperature is <1030℃, and after 7 consecutive rolling, it is rolled to 2.80mm, with a final rolling temperature of 876℃, a coiling temperature of 742℃, a wedge shape of 5μm, and a crown of 23μm;

[0019] In the acid continuous rolling mill, S1 is a flat roll, S2 is a tapered roll, and the others are flat rolls; a bending roll and shifting roll system is implemented, and the rolling forces are as follows:

[0020]

[0021] After annealing, unwind the coil to check for edge waviness and edge ridges. After coiling, use a bulging gauge to inspect.

[0022] Furthermore, the chemical composition of the low-grade non-oriented silicon steel edge reinforcement by mass percentage is as follows: C: 0.0026%, Si: 0.34%, Mn: 0.32%, P: 0.058%, S: 0.003%, Als: 0.35%, N: 0.0017%, O: 0.0009%, Ti: 0.0023%, with the remainder being Fe and unavoidable impurities.

[0023] Furthermore, the hot-rolled exit temperature is <1030℃, and after 7 consecutive rolling, it is rolled to 2.85mm, with a final rolling temperature of 881℃, a coiling temperature of 748℃, a wedge shape of -7μm, and a crown of 12μm;

[0024] In the acid continuous rolling mill, S1 is a flat roll, S2 is a tapered roll, and the others are flat rolls; a bending roll and shifting roll system is implemented, and the rolling forces are as follows:

[0025]

[0026] Step d: After annealing, unwind the coil and observe for edge waviness and edge ribs. After coiling, use a bulging gauge to check.

[0027] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0028] The method for improving the edge reinforcement of non-oriented silicon steel proposed in this invention has achieved significant improvements in dimensional accuracy, microstructure uniformity, and magnetic properties. Specifically, in terms of dimensional accuracy, the optimized edge reinforcement height is less than 0.2 mm, and there are no waviness defects after uncoiling, significantly improving the geometric consistency of the product. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings.

[0030] Figure 1 A photograph of the low-grade non-oriented silicon steel without edge reinforcement produced in Example 1;

[0031] Figure 2 A photograph of the low-grade non-oriented silicon steel without edge reinforcement produced in Example 2;

[0032] Figure 3 Photograph of the low-grade non-oriented silicon steel produced in Example 3 without edge reinforcement. Detailed Implementation

[0033] The technical solution adopted by this invention to solve its technical problem is as follows: Chemical composition by mass percentage: C: ≤0.0030%, Si: 0.25~0.35%, Mn: 0.25~0.35%, P: 0.050~0.065%, S: ≤0.004%, Als: 0.25~0.40%, N: ≤0.0020%, O ≤0.0015%, Ti: ≤0.0025%, with the remainder being Fe and unavoidable impurities, totaling 100% by mass. To effectively improve the edge reinforcement problem of non-oriented silicon steel, this invention proposes a comprehensive technical method covering multiple key aspects such as raw material selection, production process adjustment, and heat treatment process optimization. Regarding raw material selection, the content of elements such as silicon and carbon must be strictly controlled. Studies have shown that silicon content has a significant impact on the magnetic properties of non-oriented silicon steel; excessively high or low silicon content can lead to uneven microstructure in the edge reinforcement area. Therefore, in this method, the silicon content is precisely controlled within the range of 0.25% to ensure the uniformity of the edge structure and the stability of the magnetic properties. Meanwhile, carbon, as a crucial factor affecting recrystallization behavior, must have its content limited to extremely low levels (≤0.0030%, or even lower) to avoid adverse effects on grain growth and texture formation.

[0034] Regarding process adjustments, this method further optimizes the processing performance of the edge reinforcement area through precise control of key parameters such as rolling temperature, rolling speed, and reduction. The selection of rolling temperature is particularly crucial; excessively low temperatures may lead to insufficient recrystallization of the edge microstructure, while excessively high temperatures may cause abnormal grain growth, thus exacerbating the edge reinforcement problem. Therefore, this method recommends rolling within the range of 1030℃ to 870℃, with a rolling thickness of 2.7–2.9 mm and a coiling temperature of 730±15℃, combined with dynamic adjustments to rolling speed and reduction to achieve uniform edge microstructure. Furthermore, the crown and wedge shape control in the hot rolling process must adhere to the principle that the wedge shape is smaller than the crown shape, with the wedge shape controlled at -10 to 10 μm and the crown shape at 25±10 μm. In the continuous acid rolling process on the 5-stand mill, to ensure comprehensive control of plate thickness variation and edge reinforcement, S1 roll type is rolled as flat roll, S2 as tapered roll, and other roll types as flat roll.

[0035] The present invention will be further described in conjunction with the embodiments:

[0036] The test material was a low-grade non-oriented silicon steel sample with the following chemical composition: C: ≤0.0030%, Si: 0.25-0.35%, Mn: 0.25-0.35%, P: 0.050-0.065%, S: ≤0.004%, Als: 0.25-0.40%, N: ≤0.0020%, O ≤0.0015%, Ti: ≤0.0025%, with the remainder being Fe and unavoidable impurities, totaling 100% by mass. Examples 1-3 illustrate the process steps used in the method for preparing very low-grade non-oriented silicon steel edge reinforcement according to the present invention.

[0037] Example 1

[0038] Step a: Smelting is carried out in a converter, followed by vacuum treatment in RH. The content of elements such as carbon and silicon is strictly controlled to avoid uneven grain size. The composition is: C: 0.0030%, Si: 0.33%, Mn: 0.28%, P: 0.062%, S: 0.003%, Als: 0.36%, N: 0.0017%, O: 0.0012%, Ti: 0.0023%.

[0039] Step b: The hot rolling furnace exit temperature is <1030℃, and after 7 consecutive rolling, it is rolled to 2.75mm. The final rolling temperature is 878℃, the coiling temperature is 745℃, the wedge shape is 8μm, and the crown is 17μm.

[0040] Step c: In the acid continuous rolling mill, S1 is a flat roll, S2 is a tapered roll, and the others are flat rolls. The bending roll and shifting roll systems are implemented, and the rolling forces are as follows:

[0041]

[0042] Step d: The annealing line is switched to the CTF tube cold section. The power of fans #1 to #4 are 45W, 56W, 62W, and 84W respectively, to reduce internal stress. The annealing temperature is controlled as follows:

[0043]

[0044] Step e: After annealing, use a bulging gauge to check the edge ribs of the steel coil. The bulging gauge height is 0.2mm, and the edge waviness is approximately 0.11mm. Uncoil and observe for any edge waviness or ribs. Use a 1m level to measure; the level should make seamless contact with the surface of the steel coil, and the edge should be flat. This indicates the absence of edge ribs.

[0045] Step f: Detect magnetic properties: iron loss 5.13 W / kg, magnetic induction 1.743 T.

[0046] Example 2

[0047] Step a: Smelting is carried out in a converter, followed by vacuum treatment with RH to strictly control the nitrogen and oxygen content and suppress the formation of brittle oxide phases. The composition is: C: 0.0025%, Si: 0.31%, Mn: 0.28%, P: 0.058%, S: 0.003%, Als: 0.32%, N: 0.0018%, O: 0.0009%, Ti: 0.0024%.

[0048] Step b: The hot rolling furnace exit temperature is <1030℃, and after 7 consecutive rolling, it is rolled to 2.80mm. The final rolling temperature is 876℃, the coiling temperature is 742℃, the wedge shape is 5μm, and the crown is 23μm.

[0049] Step c: In the acid continuous rolling mill, S1 is a flat roll, S2 is a tapered roll, and the others are flat rolls. The bending roll and shifting roll systems are implemented, and the rolling forces are as follows:

[0050]

[0051] Step d: The annealing line is switched to the CTF tube cold section. The power of fans #1 to #4 are 48W, 58W, 65W, and 88W respectively, to reduce internal stress. The annealing temperature is controlled as follows:

[0052]

[0053] Step e: After annealing, use a bulging gauge to check the edge ribs of the steel coil. The bulging gauge height is 0.2mm, and the edge waviness is approximately 0.13mm. Uncoil and observe for any edge waviness or ribs. Use a 1m level to measure; the level should make seamless contact with the surface of the steel coil, and the edge should be flat. This indicates the absence of edge ribs.

[0054] Step f: Detect magnetic properties: iron loss 5.21 W / kg, magnetic induction 1.745 T.

[0055] Example 3

[0056] Step a: Smelting is carried out in a converter, followed by vacuum treatment with RH to strictly control the nitrogen and oxygen content and suppress the formation of brittle oxide phases. The composition is: C: 0.0026%, Si: 0.34%, Mn: 0.32%, P: 0.058%, S: 0.003%, Als: 0.35%, N: 0.0017%, O: 0.0009%, Ti: 0.0023%.

[0057] Step b: The hot rolling furnace exit temperature is <1030℃, and after 7 consecutive rolling, it is rolled to 2.85mm. The final rolling temperature is 881℃, the coiling temperature is 748℃, the wedge shape is -7μm, and the crown is 12μm.

[0058] Step c: In the acid continuous rolling mill, S1 is a flat roll, S2 is a tapered roll, and the others are flat rolls. The bending roll and shifting roll systems are implemented, and the rolling forces are as follows:

[0059]

[0060] Step d: The annealing line is switched to the CTF tube cold section. Fans #1 through #4 have power ratings of 50W, 62W, 68W, and 83W respectively to reduce internal stress. Annealing temperature control is as follows:

[0061]

[0062]

[0063] Step e: After annealing, use a bulging gauge to check the edge ribs of the steel coil. The bulging gauge height is 0.2mm, and the edge waviness is approximately 0.12mm. Uncoil and observe for any edge waviness or ribs. Use a 1m level to measure; the level should make seamless contact with the surface of the steel coil, and the edge should be flat. This indicates the absence of edge ribs.

[0064] Step f: Detect magnetic properties: iron loss 5.16 W / kg, magnetic induction 1.744 T.

[0065] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for improving the edge reinforcement of low-grade non-oriented silicon steel, characterized in that, include: Rolling is carried out at a temperature between 1030℃ and 870℃, with a rolling thickness of 2.7 to 2.9 mm and a coiling temperature of 730±15℃. In the hot rolling process, the control of crown and wedge shape must follow the principle that the wedge shape is smaller than the crown shape, with the wedge shape controlled at -10 to 10 μm and the crown shape controlled at 25 ± 10 μm.

5. Continuous acid rolling process: S1 roll type is rolled as flat roll, S2 as tapered roll, and other roll types are rolled as flat roll.

2. The method for improving the edge reinforcement of low-grade non-oriented silicon steel according to claim 1, characterized in that, The chemical composition of the low-grade non-oriented silicon steel edge reinforcement by mass percentage is as follows: C: ≤0.0030%, Si: 0.25~0.35%, Mn: 0.25~0.35%, P: 0.050~0.065%, S: ≤0.004%, Als: 0.25~0.40%, N: ≤0.0020%, O≤0.0015%, Ti: ≤0.0025%, with the remainder being Fe and unavoidable impurities, totaling 100% by mass.

3. The method for improving the edge reinforcement of low-grade non-oriented silicon steel according to claim 1, characterized in that, The chemical composition of the low-grade non-oriented silicon steel edge reinforcement by mass percentage is as follows: C: 0.0030%, Si: 0.33%, Mn: 0.28%, P: 0.062%, S: 0.003%, Als: 0.36%, N: 0.0017%, O: 0.0012%, Ti: 0.0023%, with the remainder being Fe and unavoidable impurities.

4. The method for improving the edge reinforcement of low-grade non-oriented silicon steel according to claim 3, characterized in that, The hot-rolled exit temperature is <1030℃. After 7 consecutive rolling, it is rolled to 2.75mm. The final rolling temperature is 878℃, the coiling temperature is 745℃, the wedge shape is 8μm, and the crown is 17μm. In the acid continuous rolling mill, S1 is a flat roll, S2 is a tapered roll, and the others are flat rolls; a bending roll and shifting roll system is implemented, and the rolling forces are as follows: After annealing, unwind the coil to check for edge waviness and edge ridges. After coiling, use a bulging gauge to inspect.

5. The method for improving the edge reinforcement of low-grade non-oriented silicon steel according to claim 1, characterized in that, The chemical composition of the low-grade non-oriented silicon steel edge reinforcement by mass percentage is as follows: C: 0.0025%, Si: 0.31%, Mn: 0.28%, P: 0.058%, S: 0.003%, Als: 0.32%, N: 0.0018%, O: 0.0009%, Ti: 0.0024%, with the remainder being Fe and unavoidable impurities.

6. The method for improving the edge reinforcement of low-grade non-oriented silicon steel according to claim 5, characterized in that, The hot-rolled exit temperature is <1030℃, and after 7 consecutive rolling, it is rolled to 2.80mm. The final rolling temperature is 876℃, the coiling temperature is 742℃, the wedge shape is 5μm, and the crown is 23μm. In the acid continuous rolling mill, S1 is a flat roll, S2 is a tapered roll, and the others are flat rolls; a bending roll and shifting roll system is implemented, and the rolling forces are as follows: After annealing, unwind the coil to check for edge waviness and edge ridges. After coiling, use a bulging gauge to inspect.

7. The method for improving the edge reinforcement of low-grade non-oriented silicon steel according to claim 1, characterized in that, The chemical composition of the low-grade non-oriented silicon steel edge reinforcement by mass percentage is as follows: C: 0.0026%, Si: 0.34%, Mn: 0.32%, P: 0.058%, S: 0.003%, Als: 0.35%, N: 0.0017%, O: 0.0009%, Ti: 0.0023%, with the remainder being Fe and unavoidable impurities.

8. The method for improving the edge reinforcement of low-grade non-oriented silicon steel according to claim 7, characterized in that, The hot-rolled furnace exit temperature is <1030℃, and after 7 consecutive rolling, it is rolled to 2.85mm. The final rolling temperature is 881℃, the coiling temperature is 748℃, the wedge shape is -7μm, and the crown is 12μm. In the acid continuous rolling mill, S1 is a flat roll, S2 is a tapered roll, and the others are flat rolls; a bending roll and shifting roll system is implemented, and the rolling forces are as follows: Step d: After annealing, unwind the coil and observe for edge waviness and edge ribs. After coiling, use a bulging gauge to check.

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