Method for controlling edge drop of silicon steel

Abstract

The invention relates to a thin-strip continuous casting silicon steel plate shape control technology, in particular to a method for controlling silicon steel edge drop. According to the invention, the roll shape of the double-roll cast-rolling crystallization roll is designed, and the roll shape of the crystallization roll is divided into an edge region and a middle region. The purpose of controlling the edge plate shape and the edge drop of the continuous casting thin strip steel is achieved by controlling the roll shape parameters of the edge area, and the edge drop of the hot-rolled silicon steel thin strip steel after one-pass hot rolling is effectively controlled. And meanwhile, the aim of coordinately controlling the edge drop of the thin strip steel of the hot-rolled silicon steel is achieved by controlling the thrust of a side sealing plate at the edge of a crystallization roller and the temperature of the thin strip steel before hot rolling. By means of the crystallization roller shape design, the edge drop of thin-strip continuous casting silicon steel thin strip steel, hot-rolled silicon steel thin strip steel and cold-rolled silicon steel thin strip steel is controlled, the rolling ability, the yield and the edge quality of cold rolling are improved, the value of the same-plate difference of cold-rolled silicon steel is reduced, and the plate shape quality of silicon steel is effectively improved.

Description

Technical Field

[0001] The invention belongs to the field of steel production, and in particular relates to a method for controlling edge drop of silicon steel. Background Art

[0002] The thin strip continuous casting silicon steel process is to pass the molten silicon steel water through the distribution system and into a pair of crystallization rollers rotating in opposite directions, and output thin strip steel as the crystallization rollers rotate. Subsequently, the thin strip steel is hot rolled into ultra-thin strip steel products.

[0003] The shape of continuous-cast silicon steel strip, especially the edge shape, has a direct impact on the edge drop of both hot-rolled and cold-rolled silicon steel. Excessive edge drop in the hot-rolled raw material can lead to uneven widthwise rolling reduction during cold rolling, which can cause edge cracking or damage, leading to severe cold-rolled strip breakage. Furthermore, large edge drop in the finished cold-rolled product can lead to poor sheet-to-sheet variation, severely impacting the yield rate and quality of silicon steel production.

[0004] Existing edge drop control for finished silicon steel products primarily focuses on the cold rolling process, without addressing the control of hot-rolled raw materials, let alone edge shape control for hot-rolled thin silicon steel strip produced using the twin-roll casting process. Patent document 201410337604.5 uses a five-stand cold-rolled silicon steel work roll shifting mill as a research object. Finite element analysis is used to determine the edge drop control efficiency coefficient for the shifting roll adjustment through elastic-plastic material settings, contact boundary configuration, and model meshing, thereby controlling edge thinning. Patent document 201810861619.X discloses a method for edge drop control in silicon steel production at Sendkimier. This method effectively controls edge drop by designing a cold-rolling intermediate roll profile function and implementing a shifting roll control strategy. Patent document 202210294922.2 utilizes segmented cold-roll roll profile design and control of runout parameters to reduce the roll chamfer change rate at the strip edge, homogenize edge stress, prevent strip breakage, and control edge drop. Patent document 202311466960.2 achieves high-speed and stable rolling of non-oriented silicon steel while meeting edge drop requirements by setting a cold rolling roll bending system, roll shifting system, roll process parameters, and rolling lubrication conditions. Patent document 201920454964.1 reduces silicon steel edge drop by controlling the arc segments and arc degrees formed at both ends of the cold rolling rolls. Patent document 202411733332.0 designs a control method for the intermediate roll profile, device, equipment, and media of a cold rolling mill to control the strip edge drop to no more than a preset edge drop threshold, thereby achieving the goal of controlling edge drop.

[0005] The existing technology cannot solve the problem of the edge shape of thin strip continuous casting silicon steel strip and hot rolled silicon steel strip, and does not involve solving the problem of large edge drop of thin strip continuous casting silicon steel strip and hot rolled silicon steel strip. It can be seen that how to control the edge drop of thin strip continuous casting silicon steel strip is still a gap in the existing technology. Summary of the Invention

[0006] The present invention aims to provide a production method for controlling the edge drop of thin-strip continuous casting silicon steel. By designing the roll profile of the twin-roll casting crystallization roll, the roll profile is divided into an edge region and a middle region. By controlling the roll profile parameters of the edge region, the edge shape of the continuously cast thin strip is controlled, thereby controlling the edge drop of the hot-rolled silicon steel thin strip after a single hot rolling pass. Simultaneously, by controlling the thrust of the side sealing plates at the edge of the crystallization roll and the temperature of the thin strip before hot rolling, the edge drop of the hot-rolled thin strip is coordinated and controlled.

[0007] The present invention solves the problems of edge cracking, edge loss and strip breakage of silicon steel with high silicon content during cold rolling by controlling the edge drop of hot-rolled silicon steel thin strip, effectively improves the cold rolling ability and cold rolling yield, and effectively controls the edge drop of cold-rolled silicon steel finished products and the difference between the same plate.

[0008] The present invention specifically adopts the following technical solutions:

[0009] According to a first aspect of the present invention, a method for controlling edge drop of silicon steel is provided, the method comprising:

[0010] 1) Thin strip continuous casting: Molten steel with qualified composition is obtained through steelmaking in an electric furnace or converter, with a Si content of at least 2.0 wt%, a Mn content of less than 0.5 wt%, an Al content of at least 0.6 wt%, and a ratio of Mn to Si content of less than 0.25. The molten steel is passed through a pair of counter-rotating crystallization rollers and continuously cast into thin strip steel. The thickness H of the cast thin strip steel is less than 2.2 mm.

[0011] 2) The end of the crystallization roller is closed by a side sealing plate to form a molten pool area, and a side sealing thrust F is applied to the back of the side sealing plate, and the value of F is less than 500N;

[0012] 3) Determine the crystallization roller shape:

[0013] The length of the crystallization roll is L. The roll shape of the crystallization roll is divided into three parts: the side roll shape and the middle roll shape. The side roll shapes on both sides are symmetrical with respect to the center line of the casting roll length. The length E of the side roll shape is the distance from the end of the crystallization roll to the center line of the casting roll length.

[0014] 4) The curve of the edge roller is:

[0015] y=A+8.1*10 -13 *x-0.54*10 -2 *x 2 -1.2*10 -17 *x 3 +A1*10 -8 *x 4 +6.52*10-23 *x 5 -

[0016] 1.3*10 -13 *x 6 -1.5*10 -28 *x 7 +1.55*10 -19 *x 8 +1.21*10 -34 *x 9 ,

[0017] Among them, A is the coefficient related to the thermal expansion performance of the crystallization roller, A1 is the correlation coefficient for controlling the edge drop of the silicon steel thin strip, x is the position value in the length direction of the crystallization roller, and y is the roll shape value of the crystallization roller at x;

[0018] 5) The curve of the middle roller is:

[0019] z=B+B1*10 -18 *x+B2*10 -4 *x 2 ,

[0020] Among them, B and B2 are the correlation coefficients for controlling the convexity of silicon steel thin strip, and B1 is the empirical parameter for controlling the flatness of silicon steel thin strip;

[0021] 6) The continuously cast thin strip steel is discharged from the rotating crystallization roller, and then fed into the hot box roller through the guide plate, and then subjected to one hot rolling process to be hot-rolled thin strip steel. The temperature of the thin strip steel before entering the hot rolling mill is T, and the hot-rolled thin strip steel is coiled into a coil by the coiler. The thickness h of the hot-rolled silicon steel thin strip steel is less than 1.6 mm;

[0022] 7) Hot-rolled thin strip steel is pickled to remove surface oxide scale, and then rolled into cold-rolled thin strip steel with a thickness of ≤0.5mm through continuous rolling or single-stand cold rolling, and then annealed and coated to form the final silicon steel coil.

[0023] According to the method for controlling silicon steel edge drop of the present invention, preferably, the ratio of the Mn element content to the Si element content in the silicon steel molten steel does not exceed 0.2.

[0024] According to the method for controlling silicon steel edge drop of the present invention, preferably, the length of the crystallization roller is between 500 and 2000 mm.

[0025] According to the method for controlling silicon steel edge drop of the present invention, preferably, the edge roll length E ranges from 100 to 500 mm.

[0026] According to the method for controlling silicon steel edge drop of the present invention, preferably, the value range of the side sealing thrust F does not exceed 470N.

[0027] According to the method for controlling silicon steel edge drop of the present invention, preferably, the value range of the edge roll curve parameter A is 600-1300.

[0028] According to the method for controlling silicon steel edge drop of the present invention, preferably, the value range of the edge roll curve parameter A1 is 4.02 to 4.07.

[0029] According to the method for controlling silicon steel edge drop of the present invention, preferably, the value range of the intermediate roll profile parameter B is 350-950.

[0030] According to the method for controlling silicon steel edge drop of the present invention, preferably, the value range of the intermediate roll profile parameter B1 is 2.05 to 9.50.

[0031] According to the method for controlling silicon steel edge drop of the present invention, preferably, the value range of the intermediate roll profile parameter B2 is 1.03 to 9.15.

[0032] According to the method for controlling silicon steel edge drop of the present invention, preferably, the temperature of the continuously cast thin strip steel before entering the hot rolling mill is below 1020°C.

[0033] According to the method for controlling silicon steel edge drop of the present invention, preferably, by controlling the roll profile of the crystallization roll and the side sealing thrust and the hot rolling temperature, the edge drop of the hot-rolled silicon steel thin strip is between -5 and 6 μm.

[0034] According to the method for controlling edge drop of silicon steel of the present invention, preferably, the edge drop of the cold-rolled thin strip steel is between -2 and 3 μm.

[0035] Beneficial technical effects

[0036] Compared with the prior art, the technical concept and corresponding technical solutions of the present invention can at least achieve the following beneficial technical effects:

[0037] The present invention fully considers the edge drop problem of silicon steel thin strip during the production process, and for the first time controls the plate shape of the continuously cast silicon steel thin strip during the continuous casting process, especially the control of the edge shape and edge drop. Through the targeted and individual design of the edge roll shape of the crystallization roller and the use of high-order curves, the flexible adjustment of the edge roll shape is achieved, thereby realizing the control of the edge shape and edge drop of the cast silicon steel thin strip. Considering the influence of the side sealing thrust of the crystallization roller end on the edge roll shape of the high-temperature crystallization roller during continuous casting, the side sealing thrust is controlled to further reduce the edge drop of the continuously cast silicon steel thin strip. By controlling the edge shape and edge drop of the cast silicon steel thin strip from the source, the edge drop control of hot-rolled and cold-rolled silicon steel thin strip is realized. By controlling the edge reduction of hot-rolled silicon steel thin strips, the problems of edge cracking, edge damage and strip breakage during cold rolling are solved, the rollability, yield rate and edge quality of cold rolling are improved, the difference between the same plate of cold-rolled silicon steel is reduced, and the plate shape and quality of silicon steel are effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments. Obviously, the drawings described below only relate to some embodiments of the present invention, and are not intended to limit the present invention.

[0039] Figure 1 It is a schematic diagram of the crystallization roller profile of thin strip continuous casting silicon steel thin strip.

[0040] Figure 2 It is a schematic diagram of the edge shape of the thin strip continuous casting silicon steel thin strip of the present invention.

[0041] Figure 3 It is a comparison chart. DETAILED DESCRIPTION

[0042] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Unless otherwise defined, technical or scientific terms used in the present invention shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0044] The following are embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments that can be obtained by ordinary technicians in this field without making any creative work are within the scope of protection of the present invention.

[0045] Example 1

[0046] Silicon steel molten steel with qualified composition is obtained through electric furnace or converter steelmaking, wherein the Si content of the molten steel is 2.3wt%, the Mn content is 0.3wt%, the Al content is 0.8wt%, and the ratio of the Mn content to the Si content in the molten steel is 0.13.

[0047] Molten steel passes through a pair of counter-rotating crystallization rollers and is continuously cast into thin strip steel. The thickness of the cast thin strip steel is 2.0 mm. The ends of the crystallization rollers are sealed with side sealing plates to form the molten pool area. The back of the side sealing plates applies a side sealing thrust F, with a value of F of 465 N.

[0048] The roller profile within 350mm of the edge of a 1400mm casting roller is:

[0049] y=1200+8.1*10 -13 *x-0.54*10 -2 *x 2 -1.2*10 -17 *x 3 +4.0467*10 -8 *x 4 +6.52*10 -

[0050] 23 *x 5 -1.3*10 -13 *x 6 -1.5*10 -28 *x 7 +1.55*10 -19 *x 8 +1.21*10 -34 *x 9 .

[0051] The middle roller shape is: z = 912 + 4.726 * 10- 18 *x+1.082*10 -4 *x 2 .

[0052] The continuously cast thin strip steel is discharged through the rotating crystallization roller, and then sent into the hot box roller through the guide plate. After one hot rolling, it is rolled into hot-rolled thin strip steel. The temperature of the thin strip steel before entering the hot rolling mill is 930℃.

[0053] The hot-rolled thin strip is coiled into a coil by a coiler. The thickness h of the hot-rolled silicon steel thin strip is 1.4 mm, and the edge reduction value is -3 μm.

[0054] The hot-rolled thin strip steel is pickled to remove the surface oxide scale, and then rolled into a cold-rolled thin strip steel with a thickness of 0.35mm through continuous rolling or single-stand cold rolling, and then annealed and coated to form the final silicon steel coil with an edge reduction of -1μm.

[0055] Example 2

[0056] Silicon steel molten steel with qualified composition is obtained through electric furnace or converter steelmaking, wherein the Si content of the molten steel is 2.7wt%, the Mn content is 0.2wt%, the Al content is above 1.0wt%, and the ratio of the Mn content to the Si content in the molten steel is 0.07.

[0057] Molten steel passes through a pair of counter-rotating crystallization rollers and is continuously cast into thin strip steel. The thickness of the cast thin strip steel is 1.8mm. The ends of the crystallization rollers are sealed with side sealing plates to form the molten pool area. The back of the side sealing plates applies a side sealing thrust F, with a value of F of 320N.

[0058] The roller profile within 450mm of the edge of a casting roller with a length of 1800mm is:

[0059] y=800+8.1*10 -13 *x-0.54*10 -2 *x 2 -1.2*10 -17 *x 3 +4.0497*10 -8 *x 4 +6.52*10 -

[0060] 23 *x 5 -1.3*10 -13 *x 6 -1.5*10 -28 *x 7 +1.55*10 -19 *x 8 +1.21*10 -34 *x 9 .

[0061] The middle roller shape is: z = 423 + 8.726 * 10- 18 *x+5.182*10 -4 *x 2 .

[0062] The continuously cast thin strip steel is discharged through the rotating crystallization roller, and then sent into the hot box roller through the guide plate. After one hot rolling, it is rolled into hot-rolled thin strip steel. The temperature of the thin strip steel before entering the hot rolling mill is 1015℃.

[0063] The hot-rolled thin strip is coiled into a coil by a coiler. The thickness h of the hot-rolled silicon steel thin strip is 1.1 mm, and the edge reduction value is 5 μm.

[0064] The hot-rolled thin strip steel is pickled to remove the surface oxide scale, and then rolled into a cold-rolled thin strip steel with a thickness of 0.5mm through continuous rolling or single-stand cold rolling, and then annealed and coated to form the final silicon steel coil with an edge reduction of 1μm.

[0065] Example 3

[0066] Silicon steel molten steel with qualified composition is obtained through electric furnace or converter steelmaking, wherein the Si content in the molten steel is 3.5wt%, the Mn content is 0.4wt%, the Al content is above 0.65wt%, and the ratio of the Mn content to the Si content in the molten steel is 0.11.

[0067] The molten steel passes through a pair of counter-rotating crystallization rollers to be continuously cast into thin strip steel, and the thickness H of the continuously cast thin strip steel is 2.1 mm. The end of the crystallization roller is closed by a side sealing plate to form a molten pool area, and a side sealing thrust F is applied to the back of the side sealing plate, and F is 280 N.

[0068] The roller profile in the range of 200 mm at the edge of the casting roller with a length of 900 mm is:

[0069] y = 950 + 8.1 * 10 -13 *x - 0.54 * 10 -2 *x 2 - 1.2 * 10 -17 *x 3 + 4.047 * 10 -8 *x 4 + 6.52 * 10 -

[0070] 23 *x 5 - 1.3 * 10 -13 *x 6 - 1.5 * 10 -28 *x 7 + 1.55 * 10 -19 *x 8 + 1.21 * 10 -34 *x 9 .

[0071] The intermediate roller profile is: z = 586 + 6.726 * 10 18 *x + 8.082 * 10 -4 *x 2 .

[0072] The continuously cast thin strip steel is guided out of the rotating crystallization roller, then is sent into a hot box roller through a guide plate, and then is rolled into hot-rolled thin strip steel through one pass hot rolling, and the temperature of the thin strip steel before entering the hot rolling mill is 860℃.

[0073] The hot-rolled thin strip steel is coiled into a coil through a coiler, and the thickness h of the hot-rolled silicon steel thin strip steel is 1.5 mm, and the edge drop value is 1 μm.

[0074] The hot-rolled thin strip steel is subjected to pickling to remove the surface oxide scale, is rolled into cold-rolled thin strip steel with a thickness of 0.27 mm through continuous rolling or single-stand cold rolling, and is subjected to annealing and coating treatment to become a final silicon steel coil, and the edge drop value is 2 μm.

[0075] The above is only a specific embodiment of the present application, and it should be pointed out that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the scope of protection of the present application.

Claims

1. A method for controlling silicon steel edge drop, characterized in that: The method comprises: 1) Thin strip continuous casting: Molten steel with qualified composition is obtained through steelmaking in an electric furnace or converter, with a Si content of at least 2.0 wt%, a Mn content of less than 0.5 wt%, an Al content of at least 0.6 wt%, and a ratio of Mn to Si content of less than 0.

25. The molten steel is passed through a pair of counter-rotating crystallization rollers and continuously cast into thin strip steel. The thickness H of the cast thin strip steel is less than 2.2 mm. 2) The end of the crystallization roller is closed by a side sealing plate to form a molten pool area, and a side sealing thrust F is applied to the back of the side sealing plate, and the value of F is less than 500N; 3) Determine the crystallization roller shape: The length of the crystallization roll is L. The roll shape of the crystallization roll is divided into three parts: the side roll shape and the middle roll shape. The side roll shapes on both sides are symmetrical with respect to the center line of the casting roll length. The length E of the side roll shape is the distance from the end of the crystallization roll to the center line of the casting roll length. 4) The curve of the edge roller is: y=A+8.1*10 -13 *x-0.54*10 -2 *x 2 -1.2*10 -17 *x 3 +A1*10 -8 *x 4 +6.52*10 -23 *x 5 - 1.3*10 -13 *x 6 -1.5*10 -28 *x 7 +1.55*10 -19 *x 8 +1.21*10 -34 *x 9 , Among them, A is the coefficient related to the thermal expansion performance of the crystallization roller, A1 is the correlation coefficient for controlling the edge drop of the silicon steel thin strip, x is the position value in the length direction of the crystallization roller, and y is the roll shape value of the crystallization roller at x; 5) The curve of the middle roller is: z=B+B1*10 -18 *x+B2*10 -4 *x 2 , Among them, B and B2 are the correlation coefficients for controlling the convexity of silicon steel thin strip, and B1 is the empirical parameter for controlling the flatness of silicon steel thin strip; 6) The continuously cast thin strip steel is discharged from the rotating crystallization roller, and then fed into the hot box roller through the guide plate, and then subjected to one hot rolling process to be hot-rolled thin strip steel. The temperature of the thin strip steel before entering the hot rolling mill is T, and the hot-rolled thin strip steel is coiled into a coil by the coiler. The thickness h of the hot-rolled silicon steel thin strip steel is less than 1.6 mm; 7) Hot-rolled thin strip steel is pickled to remove surface oxide scale, and then rolled into cold-rolled thin strip steel with a thickness of ≤0.5mm through continuous rolling or single-stand cold rolling, and then annealed and coated to form the final silicon steel coil.

2. The method for controlling silicon steel edge drop according to claim 1, wherein: The ratio of Mn element content to Si element content in silicon steel molten steel shall not exceed 0.

2.

3. The method for controlling silicon steel edge drop according to claim 1, wherein: The length of the crystallization roller is between 500 and 2000 mm.

4. The method for controlling silicon steel edge drop according to claim 1, wherein: The range of the edge roller length E is between 100 and 500 mm.

5. The method for controlling silicon steel edge drop according to claim 1, wherein: The value range of the side sealing thrust F shall not exceed 470N.

6. The method for controlling silicon steel edge drop according to claim 1, wherein: The value range of the edge roller curve parameter A is 600 to 1300.

7. The method for controlling silicon steel edge drop according to claim 1, wherein: The value range of the edge roller curve parameter A1 is 4.02 to 4.

07.

8. The method for controlling silicon steel edge drop according to claim 1, wherein: The value range of the intermediate roller profile parameter B is 350 to 950.

9. The method for controlling silicon steel edge drop according to claim 1, wherein: The value range of the intermediate roller profile parameter B1 is 2.05 to 9.

50.

10. The method for controlling silicon steel edge drop according to claim 1, wherein: The value range of the intermediate roller profile parameter B2 is 1.03 to 9.

15.

11. The method for controlling silicon steel edge drop according to claim 1, wherein: The temperature of the continuously cast thin strip steel before entering the hot rolling mill is below 1020℃.

12. The method for controlling silicon steel edge drop according to claim 1, wherein: By controlling the crystallization roll profile, side seal thrust, and hot rolling temperature, the edge drop of hot-rolled silicon steel thin strip is between -5 and 6μm.

13. The method for controlling silicon steel edge drop according to claim 1, wherein: The edge drop of cold rolled thin strip steel is between -2 and 3 μm.

Images