Control methods for eliminating protruding defects in low-grade silicon steel
By dynamically calculating the power of the edge heaters and the roll shifting control strategy, the rolling sequence and roll changing scheme were optimized, which solved the problem of convex edge defects in low-grade silicon steel on the hot continuous rolling production line and improved the yield.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANXI TAIGANG STAINLESS STEEL CO LTD
- Filing Date
- 2025-06-20
- Publication Date
- 2026-06-30
AI Technical Summary
On the 1549mm hot continuous rolling production line, low-grade silicon steel is prone to ridge defects during the mixed rolling process with grain-oriented silicon steel, which leads to folded scrap during cold rolling and affects the yield.
By dynamically calculating the edge heater power of oriented silicon steel and low-grade silicon steel, and combining it with a large-step, long-stroke roll shifting control strategy, the roll shifting position of stands F4 to F6 is adjusted, the rolling sequence and roll changing scheme are optimized, and uneven edge wear is reduced.
It effectively eliminates the protruding edge defects of low-grade silicon steel, improves the cold rolling yield, and avoids cold rolling crease defects.
Smart Images
Figure CN120619074B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of steel rolling technology, and in particular to a method for controlling the elimination of protruding ridge defects in low-grade silicon steel. Background Technology
[0002] refer to Figure 1 The existing 1549mm hot continuous rolling production line includes a furnace area, a roughing mill area, a finishing mill area, a laminar flow cooling area, and a coiling area arranged in sequence. The furnace area includes four heating furnaces arranged in sequence. The roughing mill area includes a high-pressure water descaling box, a roughing vertical roll mill (VE0), a roughing horizontal roll mill (R0), and a heat insulation cover arranged in sequence. The finishing mill area includes a rotary drum-type flying shear, a 7-stand finishing mill (F0 to F6 stands), a crown gauge and a straightness gauge, as well as a width gauge and a thickness gauge arranged in sequence. The laminar flow cooling area is equipped with laminar flow cooling equipment. The coiling area has two coilers (C1 and C2). The main production process of the 1549mm hot continuous rolling production line is as follows: The slab is first heated in a heating furnace at the temperature specified by the process. After reaching the target temperature, it enters the roughing mill for rolling. The vertical rolls control the width, and the horizontal rolls control the thickness. Reversible rolling is performed in the roughing mill, generally in 5 to 7 passes. After rolling in the roughing mill, the strip reaches the preset target thickness, width, and temperature. Then, it enters the finishing mill for seven-stand continuous rolling to achieve the preset target thickness, temperature, crown, and straightness. Afterward, the strip is cooled by laminar flow control to reach the target coiling temperature. Finally, the strip is formed into a coil by a coiler.
[0003] Low-grade silicon steel is the most widely used electrical steel sheet and one of the important materials in the power industry, widely used in the manufacture of core components for power equipment. Currently, when producing low-grade silicon steel using a 1549mm hot continuous rolling production line, significant ridge defects appear when the steel is transported to the cold rolling process after hot rolling. These ridge defects are located 30-80mm from the edge, and in severe cases, they form creases, rendering the product unusable and resulting in scrap.
[0004] The protruding ridge defect in low-grade silicon steel is mainly related to the production organization method. In the process of producing silicon steel using a 1549mm hot continuous rolling production line, low-grade silicon steel and grain-oriented silicon steel are usually mixed and rolled. The low-grade silicon steel is wide material, with a width range of 1100-1170mm (including the upper and lower boundaries), while the grain-oriented silicon steel is narrow material, with a width range of 1010-1050mm (including the upper and lower boundaries). The low-grade silicon steel and grain-oriented silicon steel are usually mixed and rolled irregularly in a ratio of 3:1 or 2:1 (production is scheduled according to the rolling plan, and the overall production method is irregular mixed rolling).
[0005] refer to Figure 2-3 , Figure 2This is a schematic diagram of the rolling pressure on strip steel during the finishing rolling process. Figure 3 This diagram illustrates the wear of finishing rolls during the mixed rolling of low-grade silicon steel and grain-oriented silicon steel. During the finishing rolling process, the strip experiences high rolling pressure at the edges, decreasing towards the center. This pressure is transmitted to the strip via the work rolls. Roll wear is primarily concentrated at the contact points between the strip edges and the rolls, with less wear closer to the center. Due to uneven roll wear, the wear is greatest at the edges where the grain-oriented silicon steel contacts the rolls. In the mixed rolling process of low-grade silicon steel (wide strip) and grain-oriented silicon steel (narrow strip), after rolling a certain number of strips, a distinct concave area will form on the roll diameter within a certain region at the edge where the grain-oriented silicon steel contacts the rolls. When the rolls exhibit the aforementioned wear pattern, during subsequent rolling of low-grade silicon steel wide stock, local thickening will occur in the areas with significant wear, resulting in a pointed or convex phenomenon. This pointed or convex phenomenon will manifest as a raised ridge during cold rolling, and in severe cases, it will lead to folded-mark scrap, which will significantly restrict cold rolling production. Summary of the Invention
[0006] To address some or all of the technical problems existing in the prior art, the present invention provides a control method for eliminating protruding defects in low-grade silicon steel.
[0007] The technical solution of the present invention is as follows:
[0008] A method for controlling the elimination of protruding ridge defects in low-grade silicon steel is provided, including:
[0009] Determine the number of oriented silicon steel blocks and the number of low-grade silicon steel blocks in the current batch of rolling units. Determine the stand roll changing scheme based on the number of oriented silicon steel blocks. Determine the rolling sequence of oriented silicon steel and low-grade silicon steel based on the stand roll changing scheme. Determine the rolling sequence of each piece of steel in the current batch of rolling units under the F4 to F6 stands of the finishing mill.
[0010] Using the preset head power calculation formula and tail power calculation formula for oriented silicon steel, as well as the head power calculation formula and tail power calculation formula for low grade silicon steel, the head power and tail power of the edge heater corresponding to each piece of oriented silicon steel, as well as the head power and tail power of the edge heater corresponding to each piece of low grade silicon steel are calculated and determined.
[0011] Based on the rolling sequence of each piece of steel under the F4 to F6 stands of the finishing mill, and the pre-set roll shifting positions of the F4 to F6 stands under different rolling sequences, determine the roll shifting positions of each piece of steel corresponding to the F4 to F6 stands.
[0012] Based on the head and tail power of the edge heater corresponding to each piece of grain-oriented silicon steel, the head and tail power of the edge heater corresponding to each piece of low-grade silicon steel, and the position of the shifting rolls of the F4 to F6 stands corresponding to each piece of steel, the edge heaters and the position of the shifting rolls of the F4 to F6 stands are adjusted accordingly to perform rolling of the current batch of rolling units.
[0013] In some implementations, the formula for calculating the head power corresponding to grain-oriented silicon steel is expressed as follows:
[0014] P head1 =△T1*h1*coff1;
[0015] Among them, P head1 The value represents the head power corresponding to the grain-oriented silicon steel, △T1 represents the temperature to be raised by the edge heater of the grain-oriented silicon steel head, h1 represents the roughing exit thickness of the grain-oriented silicon steel, and coff1 represents the preset head steel grade coefficient.
[0016] In some implementations, the formula for calculating the tail power of grain-oriented silicon steel is expressed as follows:
[0017] P tail1 =△T2*h1*coff2;
[0018] Among them, P tail1 ΔT2 represents the tail power corresponding to the grain-oriented silicon steel, ΔT2 represents the temperature to be increased by the edge heater at the tail of the grain-oriented silicon steel, and coff2 represents the preset tail steel grade coefficient.
[0019] In some implementations, the formula for calculating the head power corresponding to low-grade silicon steel is expressed as:
[0020] P head2 =△T3*h2*coff1;
[0021] △T3=(k*n+10);
[0022] Among them, P head2 The value represents the head power corresponding to low-grade silicon steel, △T3 represents the temperature to be increased by the edge heater of the low-grade silicon steel head, h2 represents the roughing exit thickness of the low-grade silicon steel, k represents the preset temperature growth coefficient, and n represents the rolling sequence of the low-grade silicon steel.
[0023] In some implementations, the formula for calculating the tail power of low-grade silicon steel is expressed as follows:
[0024] P tail2 =△T4*h2*coff2;
[0025] △T4=(k*n+21);
[0026] Among them, P tail2 This indicates the tail power corresponding to low-grade silicon steel, and △T4 indicates the temperature to be raised by the side heater at the tail of the low-grade silicon steel.
[0027] In some implementations, the head steel grade coefficient coff1 is set to 1.0, and the tail steel grade coefficient coff2 is set to 1.1.
[0028] In some implementations, the temperature growth factor k is set to 1.154.
[0029] In some implementations, the positions of the shifting rolls in stands F4 to F6 under different rolling sequences are set as follows:
[0030]
[0031]
[0032] In this context, F4 represents the F4 stand of the finishing mill, F5 represents the F5 stand of the finishing mill, and F6 represents the F6 stand of the finishing mill.
[0033] In some implementations, the roll changing scheme is determined based on the number of grain-oriented silicon steel blocks in the following manner:
[0034] When the number of grain-oriented silicon steel blocks is ≤15, roll changing is not required;
[0035] When 15 < number of grain-oriented silicon steel blocks ≤ 18, replace the work roll of F6 stand after rolling the 15th grain-oriented silicon steel block.
[0036] When the number of grain-oriented silicon steel blocks is greater than 18, after the 15th grain-oriented silicon steel block is rolled, replace the work rolls of the F5 stand and the F6 stand.
[0037] In some implementations, the rolling sequence of oriented silicon steel is numbered sequentially from 1 according to the rolling order of all oriented silicon steel, and the rolling sequence of low-grade silicon steel is numbered sequentially from 1 according to the rolling order of all low-grade silicon steel.
[0038] If the work rolls are replaced on a stand during the rolling process in the rolling unit, the rolling sequence of the grain-oriented silicon steel after the work rolls are replaced will be renumbered from 1 according to the rolling sequence of the grain-oriented silicon steel.
[0039] If the work rolls are replaced on a stand during the rolling process in the rolling unit, the rolling sequence of the low-grade silicon steel after the work rolls are replaced shall be renumbered from 1 according to the rolling sequence of the low-grade silicon steel.
[0040] If a work roll is replaced on a stand during the rolling process in a rolling unit, the rolling sequence under the stand where the work roll was replaced will be renumbered starting from 1.
[0041] The main advantages of the technical solution of this invention are as follows:
[0042] The control method for eliminating protruding edge defects in low-grade silicon steel of the present invention dynamically calculates the head and tail edge heater power corresponding to oriented silicon steel and the head and tail edge heater power corresponding to low-grade silicon steel using different calculation methods. This improves edge wear and reduces protruding edge defects in low-grade silicon steel during mixed rolling. By adopting a large-step, long-stroke roll shifting control strategy and setting the roll shifting positions of F4 to F6 stands under different rolling sequences, the wear area can be maximized, uneven wear can be improved, edge roll wear can be reduced, and the number of rolled blocks with protruding edge defects can be delayed. By determining whether to change rolls during rolling based on the number of oriented silicon steel blocks, the protruding edge defects in low-grade silicon steel during mixed rolling can be further reduced.
[0043] The control method for eliminating protruding defects in low-grade silicon steel according to the present invention can fundamentally eliminate protruding defects in low-grade silicon steel, thereby eliminating cold rolling crease defects and significantly improving the yield of cold-rolled silicon steel. Attached Figure Description
[0044] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and constitute a part of this invention, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:
[0045] Figure 1 This is a schematic diagram of the equipment layout for an existing 1549mm hot strip mill production line.
[0046] Figure 2 This is a schematic diagram of the rolling pressure on strip steel during the finishing rolling process;
[0047] Figure 3 A schematic diagram showing the wear of finishing rolls during the mixed rolling of low-grade silicon steel and grain-oriented silicon steel;
[0048] Figure 4 A flowchart illustrating a control method for eliminating protruding defects in low-grade silicon steel, provided as an embodiment of the present invention. Detailed Implementation
[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0050] The technical solutions provided by the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0051] refer to Figure 4 This invention provides a method for controlling the elimination of protruding ridge defects in low-grade silicon steel. This method is used in a 1549mm hot continuous rolling production line and includes the following steps:
[0052] Step 1: Determine the number of oriented silicon steel blocks and the number of low-grade silicon steel blocks in the current batch of rolling units. Determine the stand roll changing scheme based on the number of oriented silicon steel blocks. Determine the rolling sequence of oriented silicon steel and low-grade silicon steel based on the stand roll changing scheme. Also, determine the rolling sequence of each piece of steel in the current batch of rolling units under the F4 to F6 stands of the finishing mill.
[0053] Step 2: Using the preset head power calculation formula and tail power calculation formula for oriented silicon steel, as well as the head power calculation formula and tail power calculation formula for low grade silicon steel, calculate and determine the head power and tail power of the edge heater for each piece of oriented silicon steel, as well as the head power and tail power of the edge heater for each piece of low grade silicon steel.
[0054] Step 3: Determine the roll position of each piece of steel in the F4-F6 stands of the finishing mill according to the rolling sequence of each piece of steel and the roll position of the F4-F6 stands under different preset rolling sequences.
[0055] Step 4: Based on the head and tail power of the edge heater corresponding to each piece of grain-oriented silicon steel, the head and tail power of the edge heater corresponding to each piece of low-grade silicon steel, and the position of the shifting rolls of the F4 to F6 stands corresponding to each piece of steel, adjust the position of the edge heater and the position of the shifting rolls of the F4 to F6 stands accordingly, and perform rolling of the current batch of rolling units.
[0056] In the hot rolling process of the existing 1549mm hot continuous rolling production line, the power calculation of the edge heaters for low-grade silicon steel and oriented silicon steel is usually determined using the same calculation method and the same calculation parameters. When the edge heater power is determined using the same algorithm, the low-grade silicon steel will exhibit a convex edge phenomenon when about 10 pieces of oriented silicon steel are rolled. Currently, in the mixed rolling of low-grade silicon steel and oriented silicon steel, the F0-F3 stands typically use high-speed steel rolls without roll shifting devices, while the F4-F6 stands use ordinary high-nickel-chromium rolls with roll shifting devices. High-speed steel rolls have strong wear resistance, less wear, and less uneven wear, while the ordinary high-nickel-chromium rolls in the F4-F6 stands are prone to uneven wear. In the mixed rolling of low-grade silicon steel and oriented silicon steel, the current roll shifting control strategy mainly focuses on strip shape optimization, and the same method is usually used for roll shifting control of different stands, without considering the different working conditions of different stands. At the same time, the current rolling method only replaces the work rolls of the F0-F6 stands before the entire rolling unit is completed, without changing the rolls during the rolling process. All work rolls of the F0-F6 stands are replaced only after the strip of the entire rolling unit is completed.
[0057] The control method for eliminating protruding edge defects in low-grade silicon steel provided in this invention dynamically calculates the head and tail edge heater power corresponding to oriented silicon steel and the head and tail edge heater power corresponding to low-grade silicon steel using different calculation methods. This improves edge wear and reduces protruding edge defects in low-grade silicon steel during mixed rolling. By adopting a large-step, long-stroke roll shifting control strategy and setting the roll shifting positions of stands F4 to F6 under different rolling sequences, the wear area can be maximized, uneven wear can be improved, edge roll wear can be reduced, and the number of rolled blocks with protruding edge defects can be delayed. By determining whether to change rolls during rolling based on the number of oriented silicon steel blocks, the protruding edge defects in low-grade silicon steel during mixed rolling can be further reduced.
[0058] The control method for eliminating protruding defects in low-grade silicon steel provided in this invention can fundamentally eliminate protruding defects in low-grade silicon steel, thereby eliminating cold rolling crease defects and significantly improving the yield of cold-rolled silicon steel.
[0059] Furthermore, in this embodiment of the invention, the formula for calculating the head power corresponding to oriented silicon steel is expressed as follows:
[0060] P head1 =△T1*h1*coff1;
[0061] Among them, P head1The value represents the head power corresponding to the grain-oriented silicon steel, △T1 represents the temperature to be raised by the edge heater of the grain-oriented silicon steel head, h1 represents the roughing exit thickness of the grain-oriented silicon steel, and coff1 represents the preset head steel grade coefficient.
[0062] The formula for calculating the tail power of grain-oriented silicon steel is as follows:
[0063] P tail1 =△T2*h1*coff2;
[0064] Among them, P tail1 ΔT2 represents the tail power corresponding to the grain-oriented silicon steel, ΔT2 represents the temperature to be increased by the edge heater at the tail of the grain-oriented silicon steel, and coff2 represents the preset tail steel grade coefficient.
[0065] In this embodiment of the invention, the power of the edge heater corresponding to the oriented silicon steel is determined by the head power calculation formula and tail power calculation formula set above. Under the premise of meeting the cold rolling edge reduction requirements, the heating power of the edge heater of the oriented silicon steel can be increased as much as possible, thereby reducing the edge hardness of the oriented silicon steel and reducing edge wear through edge heating.
[0066] Furthermore, in this embodiment of the invention, the formula for calculating the head power corresponding to low-grade silicon steel is expressed as follows:
[0067] P head2 =△T3*h2*coff1;
[0068] △T3=(k*n+10);
[0069] Among them, P head2 The value represents the head power corresponding to low-grade silicon steel, △T3 represents the temperature to be increased by the edge heater of the low-grade silicon steel head, h2 represents the roughing exit thickness of the low-grade silicon steel, k represents the preset temperature growth coefficient, and n represents the rolling sequence of the low-grade silicon steel.
[0070] The formula for calculating the tail power of low-grade silicon steel is as follows:
[0071] P tail2 =△T4*h2*coff2;
[0072] △T4=(k*n+21);
[0073] Among them, P tail2 This indicates the tail power corresponding to low-grade silicon steel, and △T4 indicates the temperature to be raised by the side heater at the tail of the low-grade silicon steel.
[0074] In this embodiment of the invention, the edge heater power for low-grade silicon steel is determined using the aforementioned head and tail power calculation formulas. This allows the edge heater power to be increased gradually in the rolling sequence, reducing edge drop (excessive edge drop can easily cause protrusions in the cold rolling process) and increasing edge wear during initial rolling, thus improving the uniformity of roll wear. Simultaneously, as rolling progresses, edge wear in the oriented silicon steel causes a gradual tendency for protrusions to form in the low-grade silicon steel at positions 30-80mm. In this case, gradually increasing the edge heater power can effectively mitigate the occurrence of protrusions.
[0075] In this embodiment of the invention, in order to further improve the effect of power control of the side heater, the head steel grade coefficient coff1 is set to 1.0, the tail steel grade coefficient coff2 is set to 1.1, and the temperature growth coefficient k is set to 1.154.
[0076] The existing 1549mm hot strip mill production line generally uses flat roll rolling. The F0 to F3 stands of the finishing mill are rolled with high-speed steel rolls, which have very little wear and no roll shifting device. The F4 to F6 stands of the finishing mill use high-chromium-nickel rolls, which have great wear and uneven wear. The F4 to F6 stands have roll shifting devices, which can improve the uneven wear phenomenon.
[0077] In this embodiment of the invention, a large step size and long stroke roll shifting control strategy is adopted, which can maximize the wear area, thereby reducing edge roll wear and delaying the number of rolled blocks with protruding edges. After repeated experiments and analysis, it was determined that the roll shifting control effect is optimal when the maximum initial step size is 30mm and the roll shifting limit is ±140mm (equipment limit is ±150mm).
[0078] Specifically, in this embodiment of the invention, the roll shifting positions of stands F4 to F6 under different rolling sequences are set as follows:
[0079]
[0080]
[0081] In this context, F4 represents the F4 stand of the finishing mill, F5 represents the F5 stand of the finishing mill, and F6 represents the F6 stand of the finishing mill.
[0082] Furthermore, after adopting the aforementioned edge heater power calculation and control method and roll shifting control method, and analyzing the cold rolling ridge defect pattern, it was found that when low-grade silicon steel and grain-oriented silicon steel are mixed-rolled, ridge defects are basically not observed when the number of grain-oriented silicon steel rolling blocks is less than 15. Therefore, in this embodiment of the invention, the roll changing scheme is determined based on the number of grain-oriented silicon steel blocks using the following method:
[0083] When the number of grain-oriented silicon steel blocks is ≤15, roll changing is not required;
[0084] When 15 < number of grain-oriented silicon steel blocks ≤ 18, replace the work roll of F6 stand after rolling the 15th grain-oriented silicon steel block.
[0085] When the number of grain-oriented silicon steel blocks is greater than 18, after the 15th grain-oriented silicon steel block is rolled, replace the work rolls of the F5 stand and the F6 stand.
[0086] In this embodiment of the invention, after the 15th piece of grain-oriented silicon steel is rolled, the work roll is replaced before the subsequent silicon steel rolling is carried out, which can ensure that no protruding defects occur during the rolling of subsequent silicon steel.
[0087] Furthermore, in this embodiment of the invention, in order to facilitate the calculation and determination of relevant parameters and rolling control, the rolling sequence of oriented silicon steel is numbered sequentially from 1 according to the rolling sequence of all oriented silicon steel, and the rolling sequence of low-grade silicon steel is numbered sequentially from 1 according to the rolling sequence of all low-grade silicon steel.
[0088] If the work rolls are replaced on a stand during the rolling process in the rolling unit, the rolling sequence of the grain-oriented silicon steel after the work rolls are replaced will be renumbered from 1 according to the rolling sequence of the grain-oriented silicon steel.
[0089] If the work rolls are replaced on a stand during the rolling process in the rolling unit, the rolling sequence of the low-grade silicon steel after the work rolls are replaced shall be renumbered from 1 according to the rolling sequence of the low-grade silicon steel.
[0090] If a work roll is replaced on a stand during the rolling process in a rolling unit, the rolling sequence under the stand where the work roll was replaced will be renumbered starting from 1.
[0091] To make the above technical solutions of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0092] Example 1
[0093] In this embodiment, the rolling unit is a mixed rolling unit for low-grade silicon steel and oriented silicon steel, named 20140, with a total of 88 strips rolled. Among them, there are 4 strips of hot-rolled carbon steel of SPHC grade, 61 strips of low-grade silicon steel of DW60, DW60A, and DW60B grade, and 23 strips of oriented silicon steel of DQ grade.
[0094] The specific steps are as follows:
[0095] Step 1: Determine the number of oriented silicon steel blocks and the number of low-grade silicon steel blocks in the current batch of rolling units. Determine the stand roll changing scheme based on the number of oriented silicon steel blocks. Determine the rolling sequence of oriented silicon steel and low-grade silicon steel based on the stand roll changing scheme. Also, determine the rolling sequence of each piece of steel in the current batch of rolling units under the F4 to F6 stands of the finishing mill.
[0096] Specifically, there are 23 pieces of grain-oriented silicon steel. After the 15th piece is rolled, there are 8 pieces remaining. Therefore, after the 15th piece is rolled, the F5 and F6 work rolls are replaced. According to the roll change plan, the rolling sequence of grain-oriented silicon steel and low-grade silicon steel, as well as the rolling sequence of each piece of steel under the F4 to F6 stands of the finishing mill, are determined as follows:
[0097]
[0098]
[0099]
[0100] Step 2: Using the preset head power calculation formula and tail power calculation formula for oriented silicon steel, as well as the head power calculation formula and tail power calculation formula for low grade silicon steel, calculate and determine the head power and tail power of the edge heater for each piece of oriented silicon steel, as well as the head power and tail power of the edge heater for each piece of low grade silicon steel.
[0101] Specifically, the value of h1 is determined based on the cooling value of h1 and the actual temperature; the value of coff1 is 1.0, and the value of coff2 is 1.1; ΔT1 is 65℃, and ΔT2 is 78℃.
[0102] Based on the head power calculation formula and tail power calculation formula for grain-oriented silicon steel, the head power and tail power for grain-oriented silicon steel are as follows:
[0103] P head1 =△T1*h1*coff1=65*h1;
[0104] P tail1 =△T2*h1*coff2=78*1.1*h=85.8*h1;
[0105] The h2 value is determined based on the refrigeration value of h2 and the actual temperature; coff1 is 1.0, coff2 is 1.1; and k is 1.154.
[0106] Based on the head power calculation formula and tail power calculation formula for low-grade silicon steel, the head power and tail power for low-grade silicon steel are as follows:
[0107] P head2=(k*n+10)*h2*coff1=(1.154*n+10)*h2;
[0108] P tail2 =(k*n+21)*h2*coff2=(1.154*n+21)*h2*1.1;
[0109] Based on the above calculations, substituting the specific values of h and n for each piece of steel, the power calculation for the head and tail of the edge heater for each piece of steel is as follows:
[0110]
[0111]
[0112]
[0113] Step 3: Determine the roll position of each piece of steel in the F4-F6 stands of the finishing mill according to the rolling sequence of each piece of steel and the roll position of the F4-F6 stands under different preset rolling sequences.
[0114] Specifically, based on the rolling sequence of each steel piece under the F4 to F6 stands of the finishing mill, and the preset roll shifting positions of the F4 to F6 stands under different rolling sequences, the roll shifting positions of each steel piece under the F4 to F6 stands are determined as follows:
[0115]
[0116]
[0117]
[0118] Step 4: Based on the head and tail power of the edge heater corresponding to each piece of grain-oriented silicon steel, the head and tail power of the edge heater corresponding to each piece of low-grade silicon steel, and the position of the shifting rolls of the F4 to F6 stands corresponding to each piece of steel, adjust the position of the edge heater and the position of the shifting rolls of the F4 to F6 stands accordingly, and perform rolling of the current batch of rolling units.
[0119] The rolling results of the current rolling unit were tested and analyzed. The rolling of the unit was stable, and the shape of the grain of the oriented silicon steel and the low grade silicon steel was normal. The cold rolling was tracked, and there were no protruding defects in the low grade silicon steel of the entire rolling unit.
[0120] Example 2
[0121] In this embodiment, the rolling unit is a mixed rolling unit for low-grade silicon steel and oriented silicon steel, with the rolling unit name being 20194. The total number of rolled strips is 72, including 4 strips of hot-rolled carbon steel of SPHC and Q195L, 54 strips of low-grade silicon steel of DW80A and DW60, and 14 strips of oriented silicon steel of DQ.
[0122] The specific steps are as follows:
[0123] Step 1: Determine the number of oriented silicon steel blocks and the number of low-grade silicon steel blocks in the current batch of rolling units. Determine the stand roll changing scheme based on the number of oriented silicon steel blocks. Determine the rolling sequence of oriented silicon steel and low-grade silicon steel based on the stand roll changing scheme. Also, determine the rolling sequence of each piece of steel in the current batch of rolling units under the F4 to F6 stands of the finishing mill.
[0124] Specifically, there are 14 pieces of grain-oriented silicon steel. Therefore, the rolling unit will not change rolls during the rolling process. The rolling sequence of grain-oriented silicon steel and low-grade silicon steel, as well as the rolling sequence of each piece of steel under stands F4 to F6 of the finishing mill, are determined as follows:
[0125]
[0126]
[0127] Step 2: Using the preset head power calculation formula and tail power calculation formula for oriented silicon steel, as well as the head power calculation formula and tail power calculation formula for low grade silicon steel, calculate and determine the head power and tail power of the edge heater for each piece of oriented silicon steel, as well as the head power and tail power of the edge heater for each piece of low grade silicon steel.
[0128] Specifically, the value of h1 is determined based on the cooling value of h1 and the actual temperature; the value of coff1 is 1.0, and the value of coff2 is 1.1; ΔT1 is 65℃, and ΔT2 is 78℃.
[0129] Based on the head power calculation formula and tail power calculation formula for grain-oriented silicon steel, the head power and tail power for grain-oriented silicon steel are as follows:
[0130] P head1 =△T1*h1*coff1=65*h1;
[0131] P tail1 =△T2*h1*coff2=78*1.1*h=85.8*h1;
[0132] The h2 value is determined based on the refrigeration value of h2 and the actual temperature; coff1 is 1.0, coff2 is 1.1; and k is 1.154.
[0133] Based on the head power calculation formula and tail power calculation formula for low-grade silicon steel, the head power and tail power for low-grade silicon steel are as follows:
[0134] P head2 =(k*n+10)*h2*coff1=(1.154*n+10)*h2;
[0135] P tail2 =(k*n+21)*h2*coff2=(1.154*n+21)*h2*1.1;
[0136] Based on the above calculations, substituting the specific values of h and n for each piece of steel, the power calculation for the head and tail of the edge heater for each piece of steel is as follows:
[0137]
[0138]
[0139] Step 3: Determine the roll position of each piece of steel in the F4-F6 stands of the finishing mill according to the rolling sequence of each piece of steel and the roll position of the F4-F6 stands under different preset rolling sequences.
[0140] Specifically, based on the rolling sequence of each steel piece under the F4 to F6 stands of the finishing mill, and the preset roll shifting positions of the F4 to F6 stands under different rolling sequences, the roll shifting positions of each steel piece under the F4 to F6 stands are determined as follows:
[0141]
[0142]
[0143] Step 4: Based on the head and tail power of the edge heater corresponding to each piece of grain-oriented silicon steel, the head and tail power of the edge heater corresponding to each piece of low-grade silicon steel, and the position of the shifting rolls of the F4 to F6 stands corresponding to each piece of steel, adjust the position of the edge heater and the position of the shifting rolls of the F4 to F6 stands accordingly, and perform rolling of the current batch of rolling units.
[0144] The rolling results of the current rolling unit were tested and analyzed. The rolling of the unit was stable, and the shape of the grain of the oriented silicon steel and the low grade silicon steel was normal. The cold rolling was tracked, and there were no protruding defects in the low grade silicon steel of the entire rolling unit.
[0145] As can be seen, the control method for eliminating protruding defects in low-grade silicon steel provided by the embodiments of the present invention can fundamentally eliminate protruding defects in low-grade silicon steel, thereby eliminating cold rolling crease defects and significantly improving the yield of cold-rolled silicon steel.
[0146] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Additionally, the terms "front," "back," "left," "right," "upper," and "lower" in this document refer to the placement shown in the accompanying drawings.
[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for controlling the protrusion defects in low-grade silicon steel, characterized in that, include: Determine the number of oriented silicon steel blocks and the number of low-grade silicon steel blocks in the current batch of rolling units. Determine the stand roll changing scheme based on the number of oriented silicon steel blocks. Determine the rolling sequence of oriented silicon steel and low-grade silicon steel based on the stand roll changing scheme. Determine the rolling sequence of each piece of steel in the current batch of rolling units under the F4 to F6 stands of the finishing mill. Using the preset head power calculation formula and tail power calculation formula for oriented silicon steel, as well as the head power calculation formula and tail power calculation formula for low grade silicon steel, the head power and tail power of the edge heater corresponding to each piece of oriented silicon steel, as well as the head power and tail power of the edge heater corresponding to each piece of low grade silicon steel are calculated and determined. Based on the rolling sequence of each piece of steel under the F4 to F6 stands of the finishing mill, and the pre-set roll shifting positions of the F4 to F6 stands under different rolling sequences, determine the roll shifting positions of each piece of steel corresponding to the F4 to F6 stands. Based on the head and tail power of the edge heater corresponding to each piece of grain-oriented silicon steel, the head and tail power of the edge heater corresponding to each piece of low-grade silicon steel, and the position of the shifting rolls of the F4 to F6 stands corresponding to each piece of steel, the edge heaters and the position of the shifting rolls of the F4 to F6 stands are adjusted accordingly to perform rolling of the current batch of rolling units.
2. The control method for eliminating protruding defects in low-grade silicon steel according to claim 1, characterized in that, The formula for calculating the head power of grain-oriented silicon steel is as follows: P head1 =△T1*h1*coff1; Among them, P head1 The value represents the head power corresponding to the grain-oriented silicon steel, △T1 represents the temperature to be raised by the edge heater of the grain-oriented silicon steel head, h1 represents the roughing exit thickness of the grain-oriented silicon steel, and coff1 represents the preset head steel grade coefficient.
3. The control method for eliminating protruding defects in low-grade silicon steel according to claim 2, characterized in that, The formula for calculating the tail power of grain-oriented silicon steel is as follows: P tail1 <△T2*h1*coff2; Among them, P tail1 ΔT2 represents the tail power corresponding to the grain-oriented silicon steel, ΔT2 represents the temperature to be increased by the edge heater at the tail of the grain-oriented silicon steel, and coff2 represents the preset tail steel grade coefficient.
4. The control method for eliminating protruding defects in low-grade silicon steel according to claim 3, characterized in that, The formula for calculating the head power of low-grade silicon steel is as follows: P head2 =△T3*h2*coff1; △T3=(k*n+10); Among them, P head2 The value represents the head power corresponding to low-grade silicon steel, △T3 represents the temperature to be increased by the edge heater of the low-grade silicon steel head, h2 represents the roughing exit thickness of the low-grade silicon steel, k represents the preset temperature growth coefficient, and n represents the rolling sequence of the low-grade silicon steel.
5. The control method for eliminating protruding defects in low-grade silicon steel according to claim 4, characterized in that, The formula for calculating the tail power of low-grade silicon steel is as follows: P tail2 =△T4*h2*coff2; △T4=(k*n+21); Among them, P tail2 This indicates the tail power corresponding to low-grade silicon steel, and △T4 indicates the temperature to be raised by the side heater at the tail of the low-grade silicon steel.
6. The control method for eliminating protruding defects in low-grade silicon steel according to claim 5, characterized in that, The steel grade coefficient coff1 for the head is set to 1.0, and the steel grade coefficient coff2 for the tail is set to 1.
1.
7. The control method for eliminating protruding defects in low-grade silicon steel according to claim 5, characterized in that, The temperature growth coefficient k is set to 1.
154.
8. The control method for eliminating protruding defects in low-grade silicon steel according to claim 1 or 5, characterized in that, The roll shifting positions of stands F4 to F6 under different rolling sequences are set as follows: In this context, F4 represents the F4 stand of the finishing mill, F5 represents the F5 stand of the finishing mill, and F6 represents the F6 stand of the finishing mill.
9. The control method for eliminating protruding defects in low-grade silicon steel according to claim 8, characterized in that, The roll changing scheme is determined based on the number of grain-oriented silicon steel blocks using the following method: When the number of grain-oriented silicon steel blocks is ≤15, roll changing is not required; When 15 < number of grain-oriented silicon steel blocks ≤ 18, replace the work roll of F6 stand after rolling the 15th grain-oriented silicon steel block. When the number of grain-oriented silicon steel blocks is greater than 18, after the 15th grain-oriented silicon steel block is rolled, replace the work rolls of the F5 stand and the F6 stand.
10. The control method for eliminating protruding defects in low-grade silicon steel according to claim 1 or 9, characterized in that, The rolling sequence of oriented silicon steel is numbered sequentially from 1 according to the rolling order of all oriented silicon steels. The rolling sequence of low-grade silicon steel is numbered sequentially from 1 according to the rolling order of all low-grade silicon steels. If the work rolls are replaced on a stand during the rolling process in the rolling unit, the rolling sequence of the grain-oriented silicon steel after the work rolls are replaced will be renumbered from 1 according to the rolling sequence of the grain-oriented silicon steel. If the work rolls are replaced on a stand during the rolling process in the rolling unit, the rolling sequence of the low-grade silicon steel after the work rolls are replaced shall be renumbered from 1 according to the rolling sequence of the low-grade silicon steel. If a work roll is replaced on a stand during the rolling process in a rolling unit, the rolling sequence under the stand where the work roll was replaced will be renumbered starting from 1.