Manufacturing method of ultrathin oriented silicon steel with high lamination coefficient

Abstract

The invention discloses a manufacturing method of ultra-thin oriented silicon steel with a high lamination coefficient, and belongs to the technical field of ultra-thin oriented silicon steel. By controlling the cold rolling procedure and the annealing procedure, the reduction rate and the tensile stress of a rolling roller in the cold rolling process, the tension in the annealing process, the temperature and the tension after annealing and other factors are specifically controlled, the strip breakage rate is reduced, the strip shape of the steel strip is controlled, and meanwhile the magnetism of the steel strip is improved; a steel strip straightening procedure after annealing is added, the steel strip temperature, the applied tension and the steel strip speed in the straightening process are controlled, the strip shape of the steel strip is further adjusted, the magnetism of the steel strip is improved, and the stacking coefficient of the ultrathin oriented silicon steel strip is increased. Wherein the stacking coefficient can reach 96% or above, the magnetic performance B8 reaches 1.70 T or above, the iron loss P1.5 / 400 reaches 9 w / kg or below, and the ultrathin oriented silicon steel strip which is good and stable in plate shape, good in magnetic performance and good in iron loss performance and ranges from 0.03 mm to 0.08 mm is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of ultra-thin oriented silicon steel, and in particular relates to a method for manufacturing ultra-thin oriented silicon steel with a high lamination coefficient. Background Art

[0002] Ultra-thin oriented silicon steel refers to iron-silicon alloy strips with a thickness of ≤0.1mm, which are mainly used to make the cores of devices such as anode saturated reactors, choke coils, and inductor coils under medium and high frequency conditions of ≥400Hz. Ultra-thin oriented silicon steel is mainly processed and prepared using high magnetic induction oriented silicon steel finished products or bottom-free high magnetic induction oriented silicon steel as raw materials. Due to the large grain size of the raw materials, the strip itself is brittle and hard, and edge cracks and strip breaks are prone to occur during the strip rolling process, which seriously affects productivity. In addition, as the rolling progresses, the strip becomes thinner and thinner, and the strip shape becomes more difficult to control. It is easy to have plate shape problems such as edge waves and convex strips, resulting in poor plate shape of ultra-thin oriented silicon steel strips and low stacking coefficient, which leads to large losses and noise in the device core. Therefore, it is of great significance to improve the stacking coefficient of ultra-thin oriented silicon steel and obtain ultra-thin oriented silicon steel strips with excellent and stable plate shape of 0.03-0.10mm.

[0003] Patent CN111485089A proposes a method for manufacturing ultra-thin oriented silicon steel strips, comprising the following steps: using bottom-free oriented silicon steel with a thickness of 0.20-0.30 mm as raw material, after one rolling and one recrystallization annealing, coating with an insulating coating, and preparing ultra-thin oriented silicon steel strips with a thickness of 0.05-0.10 mm. This method realizes the manufacturing of ultra-thin oriented silicon steel strips with a short process, low cost, economy and environmental protection, but does not consider the plate shape of ultra-thin oriented silicon steel and the influence on the strip stacking coefficient.

[0004] Patent CN110241297A proposes an ultra-thin silicon steel strip and its preparation method. The bottom-free oriented silicon steel strip is cold rolled at a temperature of 200-350°C to obtain a cold-rolled strip, and then subjected to heating, insulation and cooling treatments to obtain an ultra-thin silicon steel strip. By coordinating the rolling temperature and the heating rate, warm strip rolling is used to prevent the strip from cracking during the rolling process, reduce the nucleation points per unit area in the subsequent annealing step, increase the grain size, and reduce the hysteresis loss of the strip. However, this method does not take into account the plate shape problem of ultra-thin oriented silicon steel and the impact on the strip stacking coefficient.

[0005] Patent CN111270063A discloses an ultra-thin silicon steel strip and its preparation method, wherein a oriented silicon steel strip with a thickness of 0.18-0.30 mm is subjected to three rolling processes to obtain a cold-rolled strip with a total reduction rate of 65%-80%; the reduction rate of any preceding rolling process in the cold rolling step is greater than or equal to the reduction rate of the adjacent subsequent rolling process, and the first reduction rate is greater than or equal to 40%. The strip is rolled in three passes, and the rolling reduction rate of each pass is combined with the rolling force and tensile stress to ensure that the silicon steel strip is flat and has no edge cracks, and the edge wave height is controlled to obtain an ultra-thin oriented silicon steel strip with a thickness of 0.1-0.035 mm, a thickness deviation of ±0.001 mm, an edge wave height of 0.2-0.4 mm, and a plate defect rate of less than 5%. Although this method takes into account the plate shape problem of ultra-thin oriented silicon steel, it does not take into account the influence on the strip stacking coefficient, and the stacking coefficient of the steel strip is still low.

[0006] Patent CN111004903A discloses a method for improving the η texture occupancy rate in an ultra-thin strip of oriented silicon steel, wherein a 0.18mm-0.35mm thick oriented silicon steel strip without a bottom layer is alkali washed, water washed and dried; during the rolling process, the temperature of the rolling lubricating emulsion is controlled to be 40°C to 80°C, the deformation amount of the first rolling pass is 32% to 46%, and a total of 4 to 6 passes are reciprocated and rolled to a thickness of 0.08mm to 0.03mm, and the rolling tension is less than or equal to 10KN; in the subsequent annealing process, the rolled thin strip is rapidly heated to above the recrystallization temperature at a temperature of 820°C to 860°C, ensuring that the η orientation selectively recrystallizes the nucleation more advantageously than other orientations to obtain a final high occupancy rate, so that the η texture occupancy rate reaches 76-85%, and the final ultra-thin strip has excellent magnetic properties, namely, high magnetic induction, low loss, low coercivity, and no coating magnetic induction intensity B 800 ≥1.82T, iron loss without coating P 1.5 / 400Hz ≤11W / kg. However, this method does not consider the plate shape of ultra-thin oriented silicon steel and its influence on the strip stacking coefficient.

[0007] Patent CN104831038A discloses a method for manufacturing ultra-thin oriented silicon steel strips, wherein ordinary oriented silicon steel with a thickness of 0.2-0.3 mm is subjected to two cold rolling and one intermediate annealing process, and the first cold rolling deformation is controlled to be 50-88%, and the thickness is rolled to 0.065-0.095 mm, and the second cold rolling deformation is 40-80%, and the thickness is rolled to 0.02 mm. After recrystallization annealing at 750-1150°C, an insulating coating is applied to obtain an ultra-thin oriented silicon steel strip with excellent magnetic properties of 0.02 mm thick. However, this method does not consider the plate shape of ultra-thin oriented silicon steel and the influence on the strip stacking coefficient.

[0008] Patent CN108315542A discloses a method for manufacturing an ultra-thin oriented silicon steel strip, wherein a 0.20-0.35 mm thick bottom-free oriented silicon steel sheet is subjected to 1-5 passes of cold rolling to obtain a cold-rolled sheet with a thickness of 0.01-0.1 mm, and then subjected to recrystallization annealing and coated with an insulating coating to obtain an ultra-thin oriented silicon steel strip with a thickness of 0.01-0.1 mm. By controlling the temperature, heating rate, and holding time of the recrystallization annealing, an ultra-thin oriented silicon steel strip with excellent magnetic properties is obtained, and the strip iron loss P is reduced. 1.5 / 400Hz 9-16W / kg, magnetic induction intensity B 800 It is 1.75-1.90T. However, this method does not consider the plate shape problem of ultra-thin oriented silicon steel and its influence on the strip stacking coefficient.

[0009] Therefore, it is of great significance to prepare ultra-thin oriented silicon steel strip with excellent and stable plate shape, improve its stacking coefficient and ensure good magnetic properties. Summary of the invention

[0010] The object of the present invention is to provide a method for manufacturing ultra-thin oriented silicon steel with a high stacking factor. By controlling the cold rolling process and the annealing process, an ultra-thin oriented silicon steel strip with excellent and stable plate shape is obtained, the stacking factor of the ultra-thin oriented silicon steel strip is improved, and excellent magnetic properties and iron loss performance are guaranteed.

[0011] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0012] A method for manufacturing ultra-thin oriented silicon steel with a high lamination coefficient is provided, comprising the following steps:

[0013] Using bottom-free oriented silicon steel with a thickness of 0.20-0.30 mm as raw material, after cold rolling, alkali washing, annealing, and coating with an insulating coating, an ultra-thin oriented silicon steel strip with a thickness of 0.03-0.08 mm is prepared; wherein:

[0014] During the cold rolling process, after 3-5 reciprocating rolling passes, the reduction rate of any subsequent rolling process is less than the reduction rate of the adjacent previous rolling process, and the reduction rate of each pass is controlled as follows:

[0015] The first pass reduction rate is 45-55%; the second pass reduction rate is 35-40%;

[0016] The reduction ratio of the 3rd to 5th pass satisfies the following relationship:

[0017] 1 / 2n×100%<η n <1 / (n+1)×100% (1)

[0018] In the relation (1): nIt is the reduction rate of the nth pass in the rolling process; n is the rolling pass, and its value is 3-5.

[0019] Where η=(1-h n / H n )×100%, where H n h is the initial thickness of the silicon steel strip before the nth rolling process, mm; n is the rolled thickness of the silicon steel strip after the nth rolling process, mm.

[0020] At the same time, the front tensile stress of the rolling roller in any subsequent rolling process is less than the front tensile stress of the rolling roller in the adjacent previous rolling process, that is: F n，前 <F n-1，前 ; and the front tensile stress F of the rolling roller in the nth rolling process n，前 There is the following relationship between the rolling pass n:

[0021] 30 - 4×n≤F n，前 ≤40 - 5×n (2)

[0022] The front tensile stress of the rolling roller in any rolling process must be greater than the rear tensile stress of the rolling roller, and the rear tensile stress F of the rolling roller in any rolling process n，后 and the tensile stress F before rolling n，前 The following relationship exists:

[0023] F n，后 = 70 ~ 90 % F n，前 (3)

[0024] In equations (2) and (3), n is 1-5.

[0025] A large reduction ratio is used in the first pass to make the grains undergo a large deformation at one time, which is conducive to obtaining more Gaussian textures. The reduction ratio is gradually reduced in the subsequent process to make the grains deform less and maintain the obtained Gaussian texture. According to the relationship (1), the reduction ratio after the third pass is controlled, and the reduction ratio of the nth pass must be less than the reduction ratio of the n-1th pass, that is, the reduction ratio of any subsequent rolling process should be less than the reduction ratio of the adjacent previous rolling process. This is conducive to controlling and stabilizing the shape of the steel strip, improving the stacking coefficient of the finished ultra-thin oriented silicon steel strip, stabilizing the grain size of the oriented silicon steel, stabilizing the magnetic properties of the finished ultra-thin oriented silicon steel strip, and finally obtaining ultra-thin oriented silicon steel with excellent magnetic properties.

[0026] The tensile stress F of the rolling roller in the nth rolling process n，前 Too large may cause the steel belt to break or convex strip defects. n，前 If the value is too small, it will cause the steel strip to have edge waves. The present invention controls the appropriate F according to the relationship (2). n，前As the rolling process progresses, the steel strip gradually becomes thinner, and it is necessary to control the front tension stress of the rolling roll in the subsequent rolling process to be less than the front tension stress of the rolling roll in the adjacent previous rolling process and the back tension stress F of the rolling roll in each rolling process. n，后 and the tensile stress F before rolling n，前 The relationship between satisfies formula (3) to stabilize the steel strip shape, ensure the stable control of the steel strip shape, avoid the steel strip breaking or convex strip defects during the rolling process, and improve the stacking coefficient of the finished ultra-thin oriented silicon steel strip.

[0027] A large number of pinned dislocations are generated during cold rolling. The more rolling passes, the more pinned dislocations are generated. Dislocations accumulate, resulting in lattice rotation and forming more deformation bands. The present invention controls the reduction rate of each rolling process and the front tensile stress F of the rolling roller according to the changes in the previous rolling pass and the state of each pass. n，前 and the post-tension stress F of the rolling roller n，后 , which is beneficial to control the change of grain orientation in the deformation band generated in each pass, so that the surface layer (110)

[001] component is strengthened, so that in the subsequent annealing process, the (110)

[001] grains are preferentially crystallized and grown tertiary, stabilizing the plate shape while improving the magnetic properties.

[0028] During annealing: the magnitude of the tension F applied to the steel strip 退 The relationship between the final thickness h of the steel strip after cold rolling is as follows:

[0029] 40×e 5×h <F 退 < 50×e 10×h (4)

[0030] After cold rolling, the steel strip has large deformation stress and strain, and the greater the rolling reduction rate, the greater the strain. At this time, recrystallization annealing can adjust the texture and recrystallized grain size in the oriented silicon steel on the one hand, and on the other hand, by applying tension during the annealing process, the plastic strain of the steel strip can be adjusted, and the shape of the steel strip can be further adjusted, thereby obtaining ultra-thin oriented silicon steel with a high lamination factor. The thinner the steel strip, the greater the tension F applied to the steel strip during the annealing process. 退 Should be smaller. 退 If the force is too large, the steel strip will break; if the force is too small, the force applied to the steel strip is insufficient to adjust the plastic strain of the steel strip, resulting in a poor shape of the steel strip. The present invention uses the relationship (4) to adjust the appropriate F according to the thickness h of the steel strip. 退 , which is beneficial to make the tension on the surface of the steel strip evenly distributed and improve the shape of the steel strip.

[0031] After annealing, keep the temperature of the steel strip after annealing not less than 300℃, use a straightening machine to straighten the steel strip and apply tension F 拉The force is 60-100N and the running speed of the steel belt is 30-60m / min to further adjust the shape of the steel belt.

[0032] Applying tension at a temperature not lower than 300°C is conducive to the refinement of magnetic domains inside oriented silicon steel, and improves the magnetic properties of steel strip while improving the shape of steel plate. Under the action of tensile stress, the magnetic domains inside the oriented silicon steel grains move. Under a sufficient stress level, the magnetic domains of the oriented silicon steel grains will spontaneously refine, thereby further reducing iron loss. 拉 It cannot be too small. If it is too small, the shape of the steel strip cannot be adjusted and the magnetic properties of the steel strip cannot be improved. If it is too large, the steel strip will break.

[0033] According to the above scheme, the cold rolling is as follows: using a 20-roll rolling mill, through 3-5 passes of reciprocating rolling, the 0.20-0.30mm bottom-free oriented silicon steel raw material is rolled to 0.03-0.08mm.

[0034] According to the above scheme, during the cold rolling process, the rolling speed is controlled to be 100-400 m / min, wherein the rolling speed of the first rolling process is 100-200 m / min.

[0035] The rolling process controls the rolling speed to be 100-400m / min. If it is too slow, it will affect the production efficiency, and if it is too fast, it will easily cause the steel strip to slip, which is not conducive to the stable control of the steel strip shape and reduces the stacking coefficient of the finished ultra-thin oriented silicon steel strip. At the same time, the rolling process controls the rolling speed of the first rolling process to be 100-200m / min. This is because for oriented silicon steel, the first pass has the largest reduction rate, and the first pass is also the most difficult to control the plate shape. Therefore, controlling the rolling speed of the first rolling process to be 100-200m / min is conducive to subsequent stable rolling, controlling the steel strip shape, and improving the stacking coefficient of the finished ultra-thin oriented silicon steel strip.

[0036] According to the above scheme, the annealing temperature is 800-950°C, the annealing time is 1-3 minutes, and the atmosphere is a nitrogen-hydrogen mixed gas.

[0037] According to the above scheme, the alkali washing is as follows: the cold-rolled strip is sent into an alkali washing tank for alkali washing to remove oil stains on the surface of the strip, then washed with water, and the strip is quickly dried with hot air at 40-50°C.

[0038] According to the above scheme, when applying the insulating coating, the coating drying and sintering temperature is 500-680°C.

[0039] The beneficial effects of the present invention are as follows:

[0040] The present invention provides a method for manufacturing ultra-thin oriented silicon steel with a high stacking coefficient, which reduces the strip breakage rate, controls the strip shape, and improves the magnetic properties of the steel strip by controlling the cold rolling process and the annealing process, specifically controlling the reduction rate, rolling roller tensile stress, and annealing process tension, temperature, tension, and other factors, thereby improving the magnetic properties of the steel strip. In addition, a steel strip straightening process is added after annealing to control the steel strip temperature, applied tension, and steel strip speed during the straightening process, further adjust the steel strip shape, improve the magnetic properties of the steel strip, and improve the stacking coefficient of ultra-thin oriented silicon steel strip with a thickness of 0.03-0.08 mm; wherein the stacking coefficient can reach more than 96%, the magnetic property B8 can reach more than 1.70T, and the iron loss P 1.5 / 400 Reaching below 9w / kg, an ultra-thin oriented silicon steel strip of 0.03-0.08mm with excellent and stable plate shape, excellent magnetic properties and iron loss performance was obtained. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the 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.

[0042] An embodiment of the present invention provides a method for manufacturing ultra-thin oriented silicon steel with a high lamination coefficient, comprising the following steps:

[0043] Using bottom-free oriented silicon steel with a thickness of 0.20-0.30 mm as raw material, after cold rolling, alkali washing, annealing, and coating with an insulating coating, an ultra-thin oriented silicon steel strip with a thickness of 0.03-0.08 mm is prepared; wherein:

[0044] During the cold rolling process, after 3-5 reciprocating rolling passes, the reduction rate of any subsequent rolling process is less than the reduction rate of the adjacent previous rolling process, and the reduction rate of each pass is controlled as follows:

[0045] The first pass reduction rate is 45-55%; the second pass reduction rate is 35-40%;

[0046] The reduction ratio of the 3rd to 5th pass satisfies the following relationship:

[0047] 1 / 2n×100%<η n <1 / (n+1)×100% (1)

[0048] In the relation (1): n is the reduction rate of the nth pass in the rolling process, that is, (1-h n / H n )×100%;H nh is the initial thickness of the silicon steel strip before the nth rolling process, mm; n is the rolled thickness of the silicon steel strip after the nth rolling process, in mm; n is the rolling pass, and its value is 3-5.

[0049] The front tensile stress of the rolling roller in any subsequent rolling process must be less than the front tensile stress of the rolling roller in the adjacent previous rolling process, that is: F n，前 <F n-1，前 , n is 1-5, and the front tensile stress F of the rolling roller in the nth rolling process of the rolling process n，前 There is the following relationship between the rolling pass n:

[0050] 30 - 4×n≤F n，前 ≤40 - 5×n (2)

[0051] In equation (2), n is 1-5.

[0052] The front tensile stress of the rolling roller in any rolling process must be greater than the rear tensile stress of the rolling roller, and the rear tensile stress F of the rolling roller in any rolling process n，后 and the tensile stress F before rolling n，前 The following relationship exists:

[0053] F n，后 = 70 ~ 90 % F n，前 (3)

[0054] In equation (3), n is 1-5.

[0055] During annealing:

[0056] The magnitude of the tension F applied to the steel strip during the annealing process 退 The relationship between the final thickness h of the steel strip after cold rolling is as follows:

[0057] 40×e 5×h <F 退 < 50×e 10×h (4)

[0058] After annealing, in order to further adjust the shape of the steel strip and keep the temperature of the steel strip after annealing not lower than 300℃, the steel strip is straightened by a straightening machine and a tension F is applied. 拉 The force is 60-100N and the running speed of the steel belt is 30-60m / min.

[0059] In one embodiment, during the annealing process, the annealing temperature is 800-950° C., the annealing time is 1-3 minutes, and the atmosphere is a nitrogen-hydrogen mixture.

[0060] In one embodiment, the cold rolling is: using a 20-roll rolling mill, through 3-5 passes of reciprocating rolling, the 0.20-0.30 mm bottom-free oriented silicon steel raw material is rolled to 0.03-0.08 mm.

[0061] In one embodiment, during the cold rolling process, the rolling speed is controlled to be 100-400 m / min, wherein the rolling speed of the first rolling process is 100-200 m / min.

[0062] In one embodiment, the alkali washing is as follows: the cold-rolled strip is sent into an alkali washing tank for alkali washing to remove oil stains on the surface of the strip, then washed with water, and the strip is quickly dried with hot air at 40-50°C.

[0063] In one embodiment, when applying the insulating coating, the coating drying and sintering temperature is 500-680°C.

[0064] The following are specific embodiments.

[0065] Example 1

[0066] The raw material is 0.27mm thick non-bottom oriented silicon steel, magnetic induction B 800 ≥1.89T, iron loss P 1.7 / 50 ≤1.10w / kg, after cold rolling, alkali washing, annealing, and coating with insulating coating, an ultra-thin oriented silicon steel strip with a thickness of 0.08mm is prepared.

[0067] During the cold rolling process, a 20-roll mill is used, and the rolling process in Table 1 is followed by three reciprocating rolling passes, wherein:

[0068] The first pass reduction rate is 45%, the rolling speed is 100m / min, and the front tensile stress F n，前 is 30KN, the post-tension stress F of the rolling roller n，后 It is 27KN.

[0069] The second pass reduction rate is 35%, the rolling speed is 200m / min, and the front tensile stress F n，前 is 25KN, the post-tension stress F of the rolling roller n，后 It is 17.5KN.

[0070] The third pass reduction rate is 18%, the rolling speed is 300m / min, and the front tensile stress F n，前 is 20KN, the post-tension stress F of the rolling roller n，后 It is 15KN.

[0071] The cold-rolled strip is sent to the alkali washing tank for alkali washing to remove the oil stains on the surface of the cold-rolled strip, and then washed with water, and the strip is quickly dried with hot air at 50°C.

[0072] Then annealing is carried out at 800℃×3min in a nitrogen-hydrogen mixture. The tension F applied to the steel strip during the annealing process 退 It is 110N.

[0073] After annealing, the temperature of the steel strip is maintained at 310°C, and the steel strip is straightened by a straightening machine, and a tension F is applied. 拉 The force is 60N and the running speed of the steel belt is 30m / min.

[0074] Finally, an insulating coating was applied, and the coating was dried and sintered at 600°C to obtain an ultra-thin oriented silicon steel strip with a thickness of 0.10 mm. The properties of the finished steel strip are shown in Table 2.

[0075] Table 1. Cold rolling process table of Example 1

[0076]

[0077] Example 2

[0078] The raw material is 0.23mm thick non-bottom oriented silicon steel, magnetic induction B 800 ≥1.89T, iron loss P 1.7 / 50 ≤1.10w / kg, after cold rolling, alkali washing, annealing, and coating with insulating coating, an ultra-thin oriented silicon steel strip with a thickness of 0.05mm is prepared.

[0079] A 20-roll mill is used, and the rolling process in Table 2 is followed by 4 reciprocating rolling passes, wherein:

[0080] The first pass reduction rate is 55%, the rolling speed is 100m / min, and the front tensile stress F n，前 is 35KN, the post-tension stress F of the rolling roller n，后 It is 31.5KN.

[0081] The second pass reduction rate is 35%, the rolling speed is 200m / min, and the front tensile stress F n，前 is 30KN, the post-tension stress F of the rolling roller n，后 It is 25.5KN.

[0082] The third pass reduction rate is 16.7%, the rolling speed is 300m / min, and the front tensile stress F n，前 is 25KN, the post-tension stress F of the rolling roller n，后 It is 20KN.

[0083] The fourth pass reduction rate is 12.5%, the rolling speed is 400m / min, and the front tensile stress F n，前 is 20KN, the post-tension stress F of the rolling roller n，后 It is 14KN.

[0084] The cold-rolled strip is sent to the alkali washing tank for alkali washing to remove the oil stains on the surface of the cold-rolled strip, and then washed with water, and the strip is quickly dried with hot air at 40°C.

[0085] Then annealing is carried out at a temperature of 950°C for 1 min in a nitrogen-hydrogen mixture. The magnitude of the tension F applied to the steel strip during the annealing process 退 It is 81N.

[0086] After annealing, the temperature of the steel strip is maintained at 315°C, and the steel strip is straightened by a straightening machine, and a tension F is applied. 拉 The force is 80N and the running speed of the steel belt is 60m / min.

[0087] Finally, an insulating coating was applied, and the coating was dried and sintered at 680°C to obtain an ultra-thin oriented silicon steel strip with a thickness of 0.05 mm. The properties of the finished steel strip are shown in Table 2.

[0088] Table 2. Cold rolling process rolling table of Example 2

[0089]

[0090] Example 3

[0091] The raw material is 0.20mm thick non-bottom oriented silicon steel, magnetic induction B 800 ≥1.89T, iron loss P 1.7 / 50 ≤1.10w / kg, after cold rolling, alkali washing, annealing, and coating with insulating coating, an ultra-thin oriented silicon steel strip with a thickness of 0.03mm is prepared.

[0092] A 20-roll mill is used, and the rolling process in Table 3 is followed by 5 reciprocating rolling passes, wherein:

[0093] The first pass reduction rate is 55%, the rolling speed is 200m / min, and the front tensile stress F n，前 is 26KN, the post-tension stress F of the rolling roller n，后 It is 22.1KN.

[0094] The second pass reduction rate is 40%, the rolling speed is 200m / min, and the front tensile stress F n，前 is 22KN, the post-tension stress F of the rolling roller n，后 It is 16.5KN.

[0095] The third pass reduction rate is 25%, the rolling speed is 300m / min, and the front tensile stress F n，前 is 18KN, the post-tension stress F of the rolling roller n，后 It is 15.3KN.

[0096] The fourth pass reduction rate is 15%, the rolling speed is 300m / min, and the front tensile stress Fn，前 is 14KN, the post-tension stress F of the rolling roller n，后 It is 11.9KN.

[0097] The fifth pass reduction rate is 14%, the rolling speed is 400m / min, and the front tensile stress F n，前 is 10KN, the post-tension stress F of the rolling roller n，后 It is 9KN.

[0098] The cold-rolled strip is sent to the alkali washing tank for alkali washing to remove the oil stains on the surface of the cold-rolled strip, and then washed with water, and the strip is quickly dried with hot air at 43°C.

[0099] Then annealing is carried out at a temperature of 920°C for 1 minute in a nitrogen-hydrogen mixture. The magnitude of the tension F applied to the steel strip during the annealing process 退 It is 47N.

[0100] After annealing, the temperature of the steel strip is maintained at 318°C, and the steel strip is straightened by a straightening machine, and a tension F is applied. 拉 The force is 100N and the running speed of the steel belt is 45m / min.

[0101] Finally, an insulating coating was applied, and the coating was dried and sintered at 500°C to obtain an ultra-thin oriented silicon steel strip with a thickness of 0.03 mm. The properties of the finished steel strip are shown in Table 2.

[0102] Table 3. Cold rolling process rolling table of Example 3

[0103]

[0104] Example 4

[0105] The raw material is 0.30mm thick non-bottom oriented silicon steel, magnetic induction B 800 ≥1.89T, iron loss P 1.7 / 50 ≤1.10w / kg, after cold rolling, alkali washing, annealing, and coating with insulating coating, an ultra-thin oriented silicon steel strip with a thickness of 0.08mm is prepared.

[0106] A 20-roll mill is used, and the rolling process in Table 4 is followed by three reciprocating rolling passes, wherein:

[0107] The first pass reduction rate is 45%, the rolling speed is 150m / min, and the front tensile stress F n，前 is 28KN, the post-tension stress F of the rolling roller n，后 It is 21KN.

[0108] The second pass reduction rate is 38%, the rolling speed is 200m / min, and the front tensile stress F n，前 is 25KN, the post-tension stress F of the rolling roller n，后It is 17.5KN.

[0109] The third pass reduction rate is 22%, the rolling speed is 300m / min, and the front tensile stress F n，前 is 20KN, the post-tension stress F of the rolling roller n，后 It is 15KN.

[0110] The cold-rolled strip is sent to the alkali washing tank for alkali washing to remove the oil stains on the surface of the cold-rolled strip, and then washed with water, and the strip is quickly dried with hot air at 48°C.

[0111] Then annealing is carried out at a temperature of 850°C for 2.5 minutes in a nitrogen-hydrogen mixture. The tension F applied to the steel strip during the annealing process 退 It is 60N.

[0112] After annealing, the temperature of the steel strip is maintained at 300°C, and the steel strip is straightened by a straightening machine, and a tension F is applied. 拉 The force is 100N and the running speed of the steel belt is 50m / min.

[0113] Finally, an insulating coating was applied, and the coating was dried and sintered at 550°C to obtain an ultra-thin oriented silicon steel strip with a thickness of 0.08 mm. The properties of the finished steel strip are shown in Table 2.

[0114] Table 4. Cold rolling process rolling table of Example 4

[0115]

[0116] Comparative Example 1

[0117] The raw material is 0.30mm thick non-bottom oriented silicon steel, magnetic induction B 800 ≥1.89T, iron loss P 1.7 / 50 ≤1.10w / kg, after cold rolling, alkali washing, annealing, and coating with insulating coating, an ultra-thin oriented silicon steel strip with a thickness of 0.08mm is prepared.

[0118] A 20-roll mill is used, and the rolling process in Table 5 is followed by three reciprocating rolling passes, wherein:

[0119] The first pass reduction rate is 63%, the rolling speed is 100m / min, and the front tensile stress F n，前 is 25KN, the post-tension stress F of the rolling roller n，后 It is 20KN.

[0120] The second pass reduction rate is 16%, the rolling speed is 200m / min, and the front tensile stress F n，前 is 21KN, the post-tension stress F of the rolling roller n，后 It is 19KN.

[0121] The third pass reduction rate is 15%, the rolling speed is 300m / min, and the front tensile stress F n，前 is 17KN, the post-tension stress F of the rolling roller n，后 It is 13KN.

[0122] The cold-rolled strip is sent to the alkali washing tank for alkali washing to remove the oil stains on the surface of the cold-rolled strip, and then washed with water, and the strip is quickly dried with hot air at 50°C.

[0123] Then annealing is carried out at 800℃×3min in a nitrogen-hydrogen mixture. The tension F applied to the steel strip during the annealing process 退 It is 55N.

[0124] After annealing, the temperature of the steel strip is maintained at 310°C, and the steel strip is straightened by a straightening machine, and a tension F is applied. 拉 The force is 60N and the running speed of the steel belt is 30m / min.

[0125] Finally, an insulating coating was applied, and the coating was dried and sintered at 600°C to obtain an ultra-thin oriented silicon steel strip with a thickness of 0.08 mm. The properties of the finished steel strip are shown in Table 2.

[0126] Table 5. Cold rolling process table of comparative example 1

[0127]

[0128]

[0129] Comparative Example 2

[0130] The raw material is 0.23mm thick non-bottom oriented silicon steel, magnetic induction B 800 ≥1.89T, iron loss P 1.7 / 50 ≤1.10w / kg, after cold rolling, alkali washing, annealing, and coating with insulating coating, an ultra-thin oriented silicon steel strip with a thickness of 0.05mm is prepared.

[0131] A 20-roll mill is used, and the rolling process in Table 6 is followed by 4 reciprocating rolling passes, wherein:

[0132] The first pass reduction rate is 55%, the rolling speed is 100m / min, and the front tensile stress F n，前 is 35KN, the post-tension stress F of the rolling roller n，后 It is 31.5KN.

[0133] The second pass reduction rate is 40%, the rolling speed is 200m / min, and the front tensile stress F n，前 is 30KN, the post-tension stress F of the rolling roller n，后 It is 25.5KN.

[0134] The third pass reduction rate is 15%, the rolling speed is 300m / min, and the front tensile stress F n，前 is 25KN, the post-tension stress F of the rolling roller n，后 It is 20KN.

[0135] The fourth pass reduction rate is 6%, the rolling speed is 400m / min, and the front tensile stress F n，前 is 20KN, the post-tension stress F of the rolling roller n，后 It is 14KN.

[0136] The cold-rolled strip is sent to the alkali washing tank for alkali washing to remove the oil stains on the surface of the cold-rolled strip, and then washed with water, and the strip is quickly dried with hot air at 40°C.

[0137] Then annealing is carried out at a temperature of 950°C for 1 min in a nitrogen-hydrogen mixture. The magnitude of the tension F applied to the steel strip during the annealing process 退 It is 50N.

[0138] After annealing, the temperature of the steel strip is maintained at 310°C, and the steel strip is straightened by a straightening machine, and a tension F is applied. 拉 The force is 60N and the running speed of the steel belt is 30m / min.

[0139] Finally, an insulating coating was applied, and the coating was dried and sintered at 680°C to obtain an ultra-thin oriented silicon steel strip with a thickness of 0.05 mm. The properties of the finished steel strip are shown in Table 2.

[0140] Table 6. Cold rolling process rolling table of comparative example 2

[0141]

[0142] Comparative Example 3

[0143] The raw material is 0.27mm thick non-bottom oriented silicon steel, magnetic induction B 800 ≥1.89T, iron loss P 1.7 / 50 ≤1.10w / kg, after cold rolling, alkali washing, annealing, and coating with insulating coating, an ultra-thin oriented silicon steel strip with a thickness of 0.08mm is prepared.

[0144] A 20-roll mill is used, and the rolling process in Table 1-7 is followed by three reciprocating rolling passes, wherein:

[0145] The first pass reduction rate is 48%, the rolling speed is 150m / min, and the front tensile stress F n，前 is 36KN, the post-tension stress F of the rolling roller n，后 It is 27KN.

[0146] The second pass reduction rate is 33%, the rolling speed is 200m / min, and the front tensile stress F n，前is 31KN, the post-tension stress F of the rolling roller n，后 It is 21.7KN.

[0147] The third pass reduction rate is 15%, the rolling speed is 300m / min, and the front tensile stress F n，前 is 26KN, the post-tension stress F of the rolling roller n，后 It is 19.5KN.

[0148] The cold-rolled strip is sent to the alkali washing tank for alkali washing to remove the oil stains on the surface of the cold-rolled strip, and then washed with water, and the strip is quickly dried with hot air at 48°C.

[0149] Then annealing is carried out at a temperature of 850°C for 2.5 minutes in a nitrogen-hydrogen mixture. The tension F applied to the steel strip during the annealing process 退 It is 115N.

[0150] Finally, an insulating coating was applied, and the coating was dried and sintered at 550°C to obtain an ultra-thin oriented silicon steel strip with a thickness of 0.08 mm. The properties of the finished steel strip are shown in Table 2.

[0151] Table 7. Cold rolling process table of comparative example 3

[0152]

[0153] Table 8. Properties of ultra-thin oriented silicon steel obtained in Examples 1-4 and Comparative Examples 1-3

[0154]

[0155]

[0156] It can be seen from Table 8 that when the cold rolling process meets the scope of the technical solution of the present invention and the tension applied to the steel strip by annealing after cold rolling meets the relationship (4) proposed by the present invention, the stacking coefficient of the ultra-thin oriented silicon steel strip is relatively high and can reach more than 96%, and at the same time, an ultra-thin oriented silicon steel strip product with excellent magnetic properties is obtained.

[0157] In Comparative Example 1, the first pass reduction ratio is too large, the second pass reduction ratio is too small, and the third pass reduction ratio does not satisfy the relationship (1) proposed by the present invention. The front tensile stress F n，前 Failure to satisfy the relationship (2) proposed by the present invention will result in the steel strip being easily broken, or having waves on the surface, making it difficult to adjust the plate shape, etc. The tension applied to the steel strip during annealing after cold rolling is too small, which ultimately results in a low stacking coefficient of the finished ultra-thin oriented silicon steel strip and increased iron loss.

[0158] In Comparative Example 2, the reduction rate from the third pass to the fourth pass does not satisfy the relationship (1) proposed in the present invention, the tension applied to the steel strip during annealing after cold rolling does not satisfy the relationship (4) proposed in the present invention, the tension applied during the annealing process is too small, and the steel strip is not straightened by a straightening machine after annealing, resulting in poor and unstable steel strip shape, a low stacking coefficient of the finished ultra-thin oriented silicon steel strip, reduced magnetic properties of the finished product, and a significant increase in iron loss.

[0159] In Comparative Example 3, the reduction ratio of the third pass does not satisfy the relationship (1) proposed in the present invention, and the front tensile stress F of the rolling roll in the rolling process is n，前 The relationship (2) proposed in the present invention is not satisfied. The tension applied to the steel strip during annealing after cold rolling does not satisfy the relationship (4) proposed in the present invention. The tension applied during the annealing process is too large. After the steel strip is annealed, a straightening machine is not used to straighten the steel strip, resulting in poor steel strip shape. The stacking coefficient of the finished ultra-thin oriented silicon steel strip is low, the magnetic properties of the finished product are also reduced, and the iron loss is significantly increased.

[0160] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A method for manufacturing ultra-thin oriented silicon steel with a high lamination coefficient, characterized in that: The following steps are involved: Using bottom-free oriented silicon steel with a thickness of 0.20-0.30 mm as raw material, after cold rolling, alkali washing, annealing, and coating with an insulating coating, an ultra-thin oriented silicon steel strip with a thickness of 0.03-0.08 mm is prepared; wherein: During the cold rolling process, after 3-5 reciprocating rolling passes, the reduction rate of any subsequent rolling process is less than the reduction rate of the adjacent previous rolling process, and the reduction rate of each pass is controlled as follows: The first pass reduction rate is 45-55%; the second pass reduction rate is 35-40%; The reduction ratio of the 3rd to 5th pass satisfies the following relationship: 1 / 2n×100%<η n <1 / (n+1)×100% (1) In the relation (1): n is the reduction rate of the nth pass in the rolling process; n is the rolling pass, and the value is 3-5; The front tensile stress of the rolling roller in any subsequent rolling process is less than the front tensile stress of the rolling roller in the adjacent previous rolling process, and the front tensile stress F of the rolling roller in the nth rolling process in the rolling process is n，前 There is the following relationship between the rolling pass n: 30 - 4×n≤F n，前 ≤40 - 5×n (2) The tensile stress F of the rolling roller in any rolling process n，前 Must be greater than the post-tension stress F of the rolling roller n，后 , and F n，后 With F n，前 The following relationship exists: F n，后 = 70 ~ 90 % F n，前 (3) In equations (2) and (3), n is 1-5; During the annealing process, the tension F applied to the steel strip 退 The relationship between the final thickness h of the steel strip after cold rolling is as follows: 40×e 5×h <F 退 < 50×e 10×h (4) After annealing, keep the temperature of the steel strip after annealing not less than 300℃, use a straightening machine to straighten the steel strip and apply tension F 拉 The force is 60-100N and the running speed of the steel belt is 30-60m / min.

2. The manufacturing method according to claim 1, characterized in that: The cold rolling is as follows: a 20-roll rolling mill is used to roll the bottom-free oriented silicon steel raw material of 0.20-0.30 mm to 0.03-0.08 mm through 3-5 reciprocating rollings.

3. The manufacturing method according to claim 1, characterized in that: During the cold rolling process, the rolling speed is controlled to be 100-400 m / min; wherein the rolling speed of the first rolling process is 100-200 m / min.

4. The manufacturing method according to claim 1, characterized in that: The alkali washing is as follows: the cold-rolled strip is sent into an alkali washing tank for alkali washing to remove oil stains on the surface of the strip, then washed with water, and the strip is quickly dried with hot air at 40-50°C.

5. The manufacturing method according to claim 1, characterized in that: When applying the insulating coating, the coating drying and sintering temperature is 500-680°C.

6. The manufacturing method according to claim 1, characterized in that: During the annealing process, the annealing temperature is 800-950° C., the annealing time is 1-3 minutes, and the atmosphere is a nitrogen-hydrogen mixed gas.

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