Cold rolling method of extremely thin and low iron loss oriented silicon steel

Abstract

The application discloses a cold rolling method of an extremely thin and low-iron-loss oriented silicon steel, and comprises the following steps: the thickness of a steel coil before cold rolling is 2.0-2.6 mm, normalizing and pickling are performed; a one-time cold rolling method is adopted to perform five-pass continuous reversible cold rolling: coarse surface work rolls are adopted in the first four passes, the surface roughness of the work rolls is controlled to be 2.5-3.2 mu m, fine surface work rolls are adopted in the last pass, the surface roughness of the work rolls is controlled to be 0.2-0.4 mu m; the reduction of the first pass is controlled to be 35-40 %, the reduction of the second, third and fourth passes is controlled to be 35-43 %, and the reduction of the last pass is controlled to be 25-35 %; the rolling force of each pass is controlled to be 200-600 T; the entry side tension of each pass is controlled to be 2-25 kg / mm 2 , the unit exit side tension is controlled to be 10-35 kg / mm 2 ; the speed of the first pass is controlled to be 300-390 m / min, the speed of the second pass is controlled to be 400-550 m / min, and the speed of other passes is controlled to be 700-800 m / min; and the thickness of the rolled product is 0.19-0.22 mm. The method solves the problem of low rolling efficiency of the extremely thin oriented silicon steel with a specification of 0.19-0.22 mm in large-scale industrial production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicon steel rolling, in particular to a cold rolling method of extremely thin and low iron loss oriented silicon steel. BACKGROUND

[0002] In recent years, energy-saving transformers have been widely promoted in the field of power transmission, and the market demand for extremely low iron loss oriented silicon steel has shown explosive growth. Reducing the thickness of steel strip is a key measure to manufacture extremely low iron loss oriented silicon steel. However, the rolling of extremely thin oriented silicon steel is extremely difficult, with many rolling passes, high risk of strip breakage, and long time-consuming for single roll rolling. Therefore, the production efficiency of extremely thin oriented silicon steel is low, and the output is low, which cannot meet the demand of explosive growth of the market, and the cold rolling process becomes the biggest bottleneck.

[0003] The typical product thickness specification of extremely thin oriented silicon steel is 0.19mm and 0.22mm, which is usually cold-rolled to the target thickness by a single-stand 20-roll mill in 6-8 passes. In the invention patent with the authorization announcement number CN 106583448 B, a cold rolling method of extremely thin specification high magnetic induction oriented silicon steel is disclosed, the main feature of which is that the thickness before rolling is 2.0mm-2.5mm, and the continuous reversible seven-pass cold rolling is carried out by one-time cold rolling method, which greatly improves the production efficiency of extremely thin specification high-end silicon steel, and the product has no shape quality defects and good surface quality, solving the low efficiency problem of two-time cold rolling method of extremely thin oriented silicon steel. However, the maximum hourly output of this method is 15.7 tons / hour, which still cannot meet the demand of production line capacity balance and market contract quantity. Therefore, it is imperative to continue to improve the cold rolling production efficiency of extremely thin oriented silicon steel. SUMMARY

[0004] In order to overcome the deficiencies in the prior art, the present application aims to provide a cold rolling method of extremely thin and low iron loss oriented silicon steel. The problem of low rolling efficiency of 0.19-0.22mm oriented silicon steel of extremely thin specification in large-scale industrial production is solved.

[0005] To achieve the above-mentioned purpose, the present application realizes the following technical scheme:

[0006] A cold rolling method of extremely thin and low iron loss oriented silicon steel, comprising:

[0007] The thickness of the steel coil before cold rolling is 2.0-2.6mm, and normalizing and pickling are carried out;

[0008] The steel coil is subjected to continuous reversible five-pass cold rolling by one-time cold rolling method, specifically as follows:

[0009] The first four passes adopt coarse surface work rolls, and the surface roughness of the work rolls is controlled at 2.5-3.2um, and the last pass adopts fine surface work rolls, and the surface roughness of the work rolls is controlled at 0.2-0.4um;

[0010] The reduction ratio of the first pass is controlled at 35-40%, the reduction ratio of the second, third and fourth passes is controlled at 35-43%, and the reduction ratio of the last pass is controlled at 25-35%;

[0011] The process lubrication and cooling are carried out by spraying emulsion; the plate temperature is gradually increased to 100-200°C in the first three passes; the fourth pass is rolled at a reduced temperature; and the last pass is rolled at normal temperature, with the plate temperature controlled at 65-75°C;

[0012] The plate shape is manually controlled in the first and second passes, and automatically controlled in the remaining passes;

[0013] The rolling force of each pass is controlled at 200-600T; the entry side tension of each pass is controlled at 2-25kg / mm 2 , and the exit side unit tension is controlled at 10-35kg / mm 2 ;

[0014] The speed of the first pass is controlled at 300-390m / min, the speed of the second pass is controlled at 400-550m / min, and the speed of the other passes is controlled at 700-800m / min;

[0015] The thickness of the rolled product is 0.19-0.22mm.

[0016] Preferably, the concentration of the emulsion is controlled at 3.0-4.5%, the temperature is controlled at 40-60°C, single side spraying is used in the first pass, and double side spraying is used in the last four passes; the emulsion flow rate of the entry side in the first pass is controlled at 3000-6000L / min, and the emulsion flow rate of the exit side is completely closed.

[0017] Preferably, the plate shape is manually controlled in the first and second passes, and a six-time function target plate shape curve is used, with the plate shape of the edge of the steel strip controlled at 35-+80I; the six-time function is:

[0018] F(x)=a1x+a2x 2 +a4x 4 +a6x 6

[0019] In the formula, F(x) is the target plate shape curve, a1, a2, a4 and a6 are the coefficients of the first, second, fourth and sixth items; x is the transverse coordinate, and after regularization, the middle part of the strip is taken as 0, the edge part of the driving side is taken as 8, and the edge part of the operating side is taken as 10.

[0020] Preferably, the entry side unit tension of the first pass is controlled at 2-8kg / mm 2 , and the exit side unit tension is controlled at 16-30kg / mm 2 ; the entry side unit tension of the last pass is controlled at 12-22kg / mm 2The unit tension on the exit side is controlled at 14-32 kg / mm 2 .

[0021] Preferably, the last pass rolling force is controlled at 200-350T.

[0022] Preferably, a Sendzimir 20-roll mill is used for rolling.

[0023] Compared with the prior art, the present application has the following advantages:

[0024] The present application controls the first pass work roll roughness to be 2.5-3.2 μm by increasing the roughness of the roughing roll, and increases the unit tension on the exit side by 10-35 kg / mm 2 , thereby reducing the risk of slipping and breaking the strip caused by the increase of the reduction rate.

[0025] The present application reduces the first pass reduction rate to be controlled at 35-40% by breaking the conventional reduction rate distribution mode, and reduces the risk of slipping in the first pass in multiple dimensions, thereby creating conditions for subsequent production.

[0026] The present application controls the target strip shape curve in each pass accurately, so that the edge of the steel strip is kept slightly warped, and the risk of edge cracking and breaking the strip caused by the increase of the silicon content and the reduction rate is reduced.

[0027] The present application controls the rolling deformation temperature in the first three passes to be 100-200℃ by reasonably setting the emulsion flow, so that plastic deformation is dominant, the risk of brittle fracture is reduced, and the aging rolling of high-magnetic-induction oriented silicon steel is realized.

[0028] The present application further improves the production efficiency of the extremely thin high-magnetic-induction oriented silicon steel in industrial production, and the hourly output of the extremely thin oriented silicon steel is increased from 15.7 tons / hour to 17.4 tons / hour, and the production efficiency is increased by 10%. The product has no strip shape quality defects and good surface quality. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the technical solutions of the present application, the preferred embodiments of the present application are described below in combination with specific examples, but it should not be understood as a limitation on the patent, but only as an example.

[0030] The test methods or test methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified.

[0031] The present application provides a cold rolling method of extremely thin and extremely low iron loss oriented silicon steel, comprising the following steps:

[0032] 1) The thickness of the steel coil before cold rolling is 2.0-2.6 mm, and normalizing and pickling are performed;

[0033] 2) using one cold rolling method, continuous reversible five pass cold rolling (the following sub-steps are not in order):

[0034] 2.1) the first four passes use rough working rolls, the working roll surface roughness is increased to 2.5-3.2 μm, reducing the risk of slip caused by reducing the pass reduction rate; the last pass uses fine working rolls, the working roll surface roughness is controlled at 0.2-0.4 μm;

[0035] 2.2) break the conventional pass reduction rate distribution mode, control the first pass reduction rate at 35%-40%, ensure the first pass front slip value is positive; avoid the risk of slip, the second, third and fourth passes use large reduction, control the reduction rate at 35%-43%, so that the grains are fully broken; control the reduction rate of the last pass at 25%-35%, ensure the flatness of the finished strip steel;

[0036] 2.3) use emulsion spraying for process lubrication and cooling; control the plate temperature to gradually increase to 100-200°C in the first three passes, ensure that the plate shape curve does not jump during rolling, meet the rolling speed; the fourth pass is rolled at a lower temperature; the last pass is rolled at room temperature, the plate temperature is controlled at 65-75°C;

[0037] 2.4) manually control the shape of the first and second passes, and automatically control the shape of the remaining passes;

[0038] 2.5) control the rolling force of each pass at 200-600T, among which, the rolling force of the last pass is controlled at 200-350T, to ensure that the strip steel will not be pressed thin and broken due to excessive rolling force when starting to roll in each pass; the entry side tension is controlled at 2-25 kg / mm 2 , and the unit tension at the exit is controlled at 10-35 kg / mm 2 ; which can effectively ensure the stability of the rolling process, improve the shape of the strip steel and reduce the rolling force.

[0039] 2.6) control the first pass speed at 300-390 m / min, effectively improve the first pass slip and reduce the risk of slip; control the second pass speed at 400-550 m / min, and the speed of other passes at 700-800 m / min, which can fully develop the potential of the equipment and ensure the rolling efficiency;

[0040] 2.7) the thickness of the product after rolling is 0.19-0.22 mm;

[0041] 3) follow the conventional post-process.

[0042] In step 2.3), the concentration of the emulsion is controlled at 3.0% to 4.5%, the temperature is controlled at 40°C to 60°C, single-side spraying is used in the first pass, and double-side spraying is used in the last four passes; the flow rate of the emulsion into the first pass is controlled at 3000 to 6000 L / min, and the flow rate of the emulsion out of the first pass is completely closed.

[0043] In step 2.4), the first and second passes are manually controlled by a plate shape, a six-time function target plate shape curve is used, and the plate shape of the edge of the steel strip is controlled at 35 to +80I, so that the edge of the steel strip is raised to avoid edge cracks caused by excessive control of the edge of the steel strip.

[0044] F(x) = a1x + a2x 2 + a4x 4 + a6x 6

[0045] In the formula, F(x) is the target plate shape curve, a1, a2, a4, and a6 are the coefficients of the first, second, fourth, and sixth items, x is the transverse coordinate, the middle of the steel strip is taken as 0 after normalization, the driving side edge is taken as 8, and the operating side edge is taken as 10.

[0046] Preferably, in step 2.5), the unit tension into the first pass is controlled at 2 to 8 kg / mm 2 , the unit tension out of the first pass is controlled at 16 to 30 kg / mm 2 , the unit tension into the last pass is controlled at 12 to 22 kg / mm 2 , and the unit tension out of the last pass is controlled at 14 to 32 kg / mm 2 .

[0047] Preferably, in step 2), a Sendzimir 20-roller mill is used for rolling.

[0048] The cold rolling method of the present application will be described in detail below in conjunction with Examples 1-4.

[0049] Example 1

[0050] A Sendzimir 20-roller mill is used to roll 3.21% Si oriented silicon steel, and the specific steps and control parameters are as follows:

[0051] 1) The conventional production method of oriented silicon steel is used for smelting, continuous casting, and hot rolling, the silicon steel coil is normalized and pickled before cold rolling, and the thickness of the silicon steel coil before cold rolling is 2.3 mm.

[0052] 2) A one-time cold rolling method is used to perform continuous reversible five-pass cold rolling (the following sub-steps are not in any particular order):

[0053] 2.1) The first four passes use rough working rolls (Φ68mm) with surface roughness controlled at 2.7μm; the last pass uses fine working rolls (Φ66mm) with surface roughness controlled at 0.3μm;

[0054] 2.2) The reduction is controlled at 20%~43%, wherein the first pass reduction is 39.13%, the last pass reduction is 26.1%, and the reduction of the other passes is controlled at 20%~43%. The specific reduction of each pass in this embodiment is shown in Table 1.

[0055] 2.3) The process is lubricated and cooled by spraying emulsion, the concentration of which is controlled at 3.6%, and the emulsion temperature is 48°C; the first pass uses single-side spraying, the entry-side emulsion flow is controlled at 4000L / min, and the exit-side emulsion flow is completely closed; the last four passes use double-side spraying; the plate temperature is gradually increased to 180°C in the first three passes; the fourth pass is rolled at a decreasing temperature; and the last pass is rolled at normal temperature, with the plate temperature controlled at 67°C.

[0056] 2.4) The first and second passes are manually controlled in terms of plate shape, and the following six-time function target plate shape curve is used:

[0057] F(x) = a1x + a2x 2 + a4x 4 + a6x 6

[0058] In the formula, F(x) is the target plate shape curve, a1, a2, a4, a6 are the first, second, fourth, and sixth item coefficients; x is the transverse coordinate, which is normalized, with the center of the strip taken as 0, the drive side taken as 8, and the operation side taken as 10; the plate shape of the strip edge is controlled at +70I, and the strip edge is slightly warped.

[0059] 2.5) Since it is reversible rolling, the rolling is performed simultaneously with coiling; the rolling force of each pass is controlled at 200~600T; the entry-side unit tension of each pass is controlled at 2~25kg / mm 2 , and the exit-side unit tension is controlled at 10~35kg / mm 2 , wherein the entry-side unit tension of the first pass is 2~8kg / mm 2 , and the exit-side unit tension is 16~30kg / mm 2 ; the entry-side unit tension of the finished product pass is controlled at 12~22kg / mm 2 , and the exit-side unit tension is controlled at 14~32kg / mm 2 . The specific unit tension of each pass in this embodiment is shown in Table 1.

[0060] 2.6) Stabilize the rolling speed, the first pass speed is controlled at 360 m / min, the second pass speed is controlled at 470 m / min, and the other pass speeds are controlled at 750 m / min, and the thickness of the rolled product is 0.22 mm;

[0061] 3) The post-process is performed according to the routine.

[0062] The final product of this example has excellent physical quality, the magnetic induction B800 reaches 1.89 T, the iron loss P17 / 50 is 0.68 W, and the hourly output reaches 17.4 tons.

[0063] Table 1

[0064]

[0065] Example 2

[0066] The 3.21% Si oriented silicon steel is rolled by a Sendzimir twenty-roller mill, and the specific steps and control parameters are as follows:

[0067] 1) The smelting, continuous casting and hot rolling are performed according to the routine production method of oriented silicon steel, the silicon steel coil has a thickness of 2.6 mm before cold rolling, and is normalized and pickled;

[0068] 2) The one-time cold rolling method is adopted to perform continuous reversible five-pass cold rolling (the following sub-steps are not in any particular order):

[0069] 2.1) The first four passes adopt coarse working rollers (Φ67.5 mm), and the working roller surface roughness is controlled at 3.1 μm; the last pass adopts fine working rollers (Φ67 mm), and the working roller surface roughness is controlled at 0.4 μm;

[0070] 2.2) The reduction is controlled at 20-43%, wherein the reduction of the first pass is 39.2%, the reduction of the last pass is 29%, and the reductions of the other passes are 20-43%, and the specific reductions of the passes of this example are shown in Table 2;

[0071] 2.3) The process lubrication and cooling are performed by spraying emulsion, the concentration of the emulsion is controlled at 3.0%, the emulsion temperature is 48°C; the first pass adopts single-side spraying, the inboard emulsion flow is controlled at 3800 L / min, and the outboard emulsion flow is completely closed; the last four passes adopt double-side spraying; the plate temperature is gradually increased to 190°C in the first three passes; the fourth pass is rolled at a reduced temperature; and the last pass is rolled at normal temperature, and the plate temperature is controlled at 68°C;

[0072] 2.4) The first and second passes are manually controlled in terms of the plate shape, and the following six-time function target plate shape curve is adopted:

[0073] F(x) = a1x + a2x 2 +a4x4 +a6x 6

[0074] In the formula, F(x) is the target plate shape curve, a1, a2, a4, a6 are the first, second, fourth, sixth term coefficients; x is the transverse coordinate, after the regularization treatment, the middle of the strip is taken as 0, the driving side edge is taken as 8, and the operating side edge is taken as 10; the plate shape control of the strip edge is +78I, and the strip edge is slightly warped;

[0075] 2.5) Since it is reversible rolling, the rolling is carried out at the same time as the coiling; the rolling force of each pass is controlled at 200-600T; the unit tension of the entry side of each pass is controlled at 2-25kg / mm 2 , and the unit tension of the exit side is controlled at 10-35kg / mm 2 ; wherein the unit tension of the entry side of the first pass is 2-8kg / mm 2 , and the unit tension of the exit side is 16-30kg / mm 2 ; the unit tension of the entry side of the finished pass is controlled at 12-22kg / mm 2 , and the unit tension of the exit side is controlled at 14-32kg / mm 2 ; the specific unit tension of each pass of the embodiment is shown in Table 2;

[0076] 2.6) The rolling speed is stable, the speed of the first pass is controlled at 330m / min, the speed of the second pass is controlled at 455m / min, and the speed of the other passes is controlled at 740m / min, and the thickness of the rolled product is 0.22mm;

[0077] 3) The post-process is carried out according to the conventional method.

[0078] The physical quality of the final product of the embodiment is excellent, the magnetic induction B800 reaches 1.91T, the iron loss P17 / 50 is 0.65W, and the hourly output reaches 17.6 tons.

[0079] Table 2

[0080]

[0081]

[0082] Example 3

[0083] A Sendzimir 20-roll mill is used to roll 3.21% Si oriented silicon steel, and the specific steps and control parameters are as follows:

[0084] 1) The smelting, continuous casting and hot rolling follow the conventional production method of oriented silicon steel, and the silicon steel coil is cold rolled to a thickness of 2.3mm, and is normalized and pickled;

[0085] 2) Adopting one-time cold rolling method, carrying out continuous reversible five-pass cold rolling (the following sub-steps are not in order):

[0086] 2.1) Adopting coarse surface work roll (Φ66.7mm) for the first four passes, and controlling the work roll surface roughness at 2.9μm; adopting fine surface work roll (Φ67.4mm) for the last pass, and controlling the work roll surface roughness at 0.35μm;

[0087] 2.2) Controlling the reduction rate at 20%~43%, wherein the reduction rate of the first pass is 39.1%, the reduction rate of the last pass is 29.6%, and the reduction rate of the rest passes is at 20%~43%; the specific reduction rate of each pass in this embodiment is shown in Table 3;

[0088] 2.3) Adopting emulsion spraying for process lubrication and cooling, and controlling the emulsion concentration at 3.4%, and the emulsion temperature at 50℃; adopting single-side spraying for the first pass, and controlling the emulsion flow rate at the entry side at 4300L / min, and completely closing the emulsion flow rate at the exit side; adopting double-side spraying for the last four passes; controlling the strip temperature to gradually increase to 190℃ for the first three passes; decreasing the temperature for the fourth pass; and rolling at normal temperature for the last pass, and controlling the strip temperature at 70℃;

[0089] 2.4) Manually controlling the strip shape for the first and second passes, and adopting the following six-time function target strip shape curve:

[0090] F(x) = a1x + a2x 2 + a4x 4 + a6x 6

[0091] In the formula, F(x) is the target strip shape curve, a1, a2, a4, a6 are the first, second, fourth and sixth term coefficients; x is the transverse coordinate, and after normalization, the middle part of the strip is 0, the transmission side edge part is 8, and the operation side edge part is 10; the strip shape control at the edge of the strip is +74I, and the strip edge is slightly warped;

[0092] 2.5) Since it is reversible rolling, the rolling is carried out at the same time as the coiling; the rolling force of each pass is controlled at 200~600T; the unit tension at the entry side of each pass is controlled at 2~25kg / mm 2 , and the unit tension at the exit side is controlled at 10~35kg / mm 2 , wherein the unit tension at the entry side of the first pass is 2~8kg / mm 2 , and the unit tension at the exit side is 16~30kg / mm 2 ; the unit tension at the entry side of the finished pass is controlled at 12~22kg / mm 2 , and the unit tension at the exit side is controlled at 14~32kg / mm 2 ; the specific unit tension of each pass in this embodiment is shown in Table 3;

[0093] 2.6) The rolling speed is stabilized. The speed of the first pass is controlled at 390 m / min, the speed of the second pass is controlled at 550 m / min, and the speed of other passes is controlled at 800 m / min. The thickness of the rolled product is 0.19 mm.

[0094] 3) Perform subsequent processes according to standard procedures.

[0095] The final product of this embodiment has excellent physical quality, with a magnetic induction B800 of 1.97T, an iron loss P17 / 50 of 0.62W, and an hourly output of 17.7 tons.

[0096] Table 3

[0097]

[0098] Example 4

[0099] The following are the specific steps and control parameters for rolling 3.21% Si oriented silicon steel using a Sendzimir 20-roll mill:

[0100] 1) The smelting, continuous casting, and hot rolling processes follow the conventional production methods for grain-oriented silicon steel. The thickness of the silicon steel coil before cold rolling is 2.0 mm, and it undergoes normalizing pickling.

[0101] 2) A single-pass cold rolling process is adopted, consisting of five continuous and reversible cold rolling passes (the following sub-steps are not in any particular order):

[0102] 2.1) The first four passes use rough-surfaced work rolls (Φ68.2mm), with the surface roughness of the work rolls controlled at 2.6μm; the last pass uses fine-surfaced work rolls (Φ69.1mm), with the surface roughness of the work rolls controlled at 0.32μm.

[0103] 2.2) The reduction rate is controlled between 20% and 43%, of which the reduction rate of the first pass is 37.5%, the reduction rate of the last pass is 30.9%, and the reduction rate of the remaining passes is between 20% and 43%. The specific reduction rates of each pass in this embodiment are shown in Table 4.

[0104] 2.3) Emulsion spraying is used for process lubrication and cooling. The concentration of the emulsion is controlled at 3.8%, and the emulsion temperature is 49℃. The first pass uses single-sided spraying, with the emulsion flow rate on the inlet side controlled at 4100L / min, and the emulsion flow rate on the outlet side completely shut off. The following four passes use double-sided spraying. The plate temperature is gradually increased to 194℃ in the first three passes. The fourth pass is cooled rolling. The last pass is room temperature rolling, with the plate temperature controlled at 71℃.

[0105] 2.4) The first and second manual plate shape control uses the following sixth-order function target plate shape curve:

[0106] F(x) = a1x + a2x2 +a4x 4 +a6x 6

[0107] In the formula, F(x) is the target plate shape curve, a1, a2, a4, a6 are the first, second, fourth, sixth term coefficients; x is the transverse coordinate, after the regularization processing, the middle of the strip is taken as 0, the driving side edge is taken as 8, and the operating side edge is taken as 10; the plate shape control of the strip edge is +28I, and the strip edge is slightly warped;

[0108] 2.5) Since it is reversible rolling, the rolling is carried out at the same time as the coiling; the rolling force of each pass is controlled at 200-600T; the unit tension of the entry side of each pass is controlled at 2-25kg / mm 2 , and the unit tension of the exit side is controlled at 10-35kg / mm 2 , wherein the unit tension of the entry side of the first pass is 2-8kg / mm 2 , and the unit tension of the exit side is 16-30kg / mm 2 ; the unit tension of the entry side of the finished pass is controlled at 12-22kg / mm 2 , and the unit tension of the exit side is controlled at 14-32kg / mm 2 . The specific unit tension of each pass of the embodiment is shown in Table 4;

[0109] 2.6) The stable rolling speed is controlled at 300m / min for the first pass, 400m / min for the second pass, and 700m / min for the other passes, and the thickness of the product after rolling is 0.19mm;

[0110] 3) The post-process is carried out according to the convention.

[0111] The physical quality of the final product of the embodiment is excellent, the magnetic induction B800 reaches 1.95T, the iron loss P17 / 50 is 0.63W, and the hourly output reaches 17.5 tons.

[0112] Table 4

[0113]

[0114]

[0115] In summary, the extremely thin oriented silicon steel after cold rolling according to the processes in embodiments 1-4 has a plate shape value controlled at 0-+5I, the strip is flat, the thickness precision is ±2μm, the physical quality of the product is good, the magnetic properties reach the high magnetic induction and low iron loss indexes, and the product has been used in Changji-Guquan ±1100kV, Baihetan-Jiangsu ±800kV, etc. large-scale ultra-high voltage direct current projects in China, which has effectively supported the construction of national key projects and completely replaced the imported oriented silicon steel.

[0116] The above merely illustrates the specific embodiments of the present application, and it should be noted that any changes or replacements within the technical scope disclosed by the present application can be easily conceived by any person skilled in the art, and should be covered within the protection scope of the present application, and the rest of the prior art is not described in detail.

Claims

1. A cold rolling method for ultra-thin, ultra-low iron loss grain-oriented silicon steel, characterized in that, include: The steel coils are 2.0–2.6 mm thick before cold rolling and undergo normalizing pickling. The steel coils are subjected to a single-pass cold rolling process, involving five continuous and reversible cold rolling passes, as detailed below: The first four passes use rough-surfaced work rolls with a surface roughness controlled between 2.5 and 3.2 μm, while the last pass uses fine-surfaced work rolls with a surface roughness controlled between 0.2 and 0.4 μm. The reduction rate of the first pass is controlled at 35-40%, the reduction rate of the second, third and fourth passes is controlled at 35-43%, and the reduction rate of the last pass is controlled at 25-35%. Emulsion spraying is used for process lubrication and cooling; the plate temperature is gradually increased to 100-200℃ in the first three passes; the fourth pass is cooled rolling; and the last pass is rolled at room temperature with the plate temperature controlled at 65-75℃. The first and second passes are manually controlled to control the plate shape, while the remaining passes are automatically controlled to control the plate shape. The first and second passes manually control the strip shape, using a sixth-order function target strip shape curve, with the strip edge shape controlled between 35° and +80°. The sixth-order function is: F(x)=a1x+a2x 2 +a4x 4 +a6x 6 In the formula, F(x) is the target strip shape curve, a1, a2, a4, a6 are the coefficients of the first, second, fourth, and sixth degree terms, respectively; x is the horizontal coordinate, which is 0 in the middle of the strip, 8 in the transmission side, and 10 in the operation side after regularization. The rolling force for each pass is controlled between 200 and 600 tons; the inlet tension for each pass is controlled between 2 and 25 kg / mm. 2 The unit tension on the output side is controlled between 10 and 35 kg / mm. 2 ; The speed for the first pass should be controlled at 300–390 m / min, the speed for the second pass at 400–550 m / min, and the speed for the other passes at 700–800 m / min. The thickness of the rolled product is 0.19–0.22 mm.

2. The cold rolling method for ultra-thin, ultra-low iron loss grain-oriented silicon steel according to claim 1, characterized in that, The concentration of the emulsion is controlled at 3.0-4.5%, and the temperature is controlled at 40-60℃. The first pass uses single-sided spraying, and the subsequent four passes use double-sided spraying. The flow rate of the emulsion entering the first pass is controlled at 3000-6000 L / min, and the flow rate of the emulsion exiting the first pass is completely shut off.

3. The cold rolling method for ultra-thin, ultra-low iron loss grain-oriented silicon steel according to claim 1, characterized in that, The initial inlet tension should be controlled at 2–8 kg / mm². 2 The unit tension on the output side is controlled at 16-30 kg / mm. 2 The unit tension for the final pass on the inlet side is controlled at 12–22 kg / mm². 2 The unit tension on the output side is controlled between 14 and 32 kg / mm. 2 .

4. The cold rolling method for ultra-thin, ultra-low iron loss grain-oriented silicon steel according to claim 1, characterized in that, The rolling force in the final pass is controlled between 200 and 350T.

5. The cold rolling method for ultra-thin, ultra-low iron loss grain-oriented silicon steel according to claim 1, characterized in that, The rolling process was carried out using a Sendzimir 20-roll mill.

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