A short-process production method for strong λ texture non-oriented silicon steel

Abstract

The present invention belongs to the technical field of iron and steel metallurgy, and relates to a short-process production method of non-oriented silicon steel with strong λ texture. The method of the present invention comprises: (1) smelting molten steel and producing cast strips through ultra-thin strip continuous casting equipment, with superheat of 50 to 100°C and thickness of 1.7 to 2.3 mm; (2) hot rolling after equalization to obtain hot-rolled plates with a thickness of 0.54 to 1.26 mm; (3) directly cold rolling the hot-rolled plates to 0.3 to 0.50 mm; (4) annealing, with an annealing temperature of 900 to 1050°C and an annealing time of 3 to 10 minutes. The non-oriented silicon steel produced by the present invention has a strong λ texture, including a strong Cube texture, a rotated Cube texture and a partially rotated Goss texture, and its iron loss P 1.5 / 50 The value is 1.4 to 2.1 W / kg. The present invention optimizes the casting and rolling processes and utilizes the heredity and preferential nucleation-growth characteristics of the λ texture to significantly improve the occupancy rate and strength of the λ texture. The method is energy-efficient and efficient and is convenient for industrial application.

Description

Technical Field

[0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a short-process production method of strong lambda texture non-oriented silicon steel. Background Art

[0002] Non-oriented silicon steel is an important soft magnetic material, which is used to make the iron core of motors, generators and other equipment. With the annual increase in national electricity consumption, especially the continuous expansion of the new energy vehicle market, the requirements for non-oriented electrical steel are also increasing, requiring it to have lower iron loss and higher magnetic induction.

[0003] The λ texture ({100}) has the advantages of preferential nucleation and selective growth, and has a uniform easy magnetization direction in the circumferential direction. <100> , which can effectively improve the magnetic induction of non-oriented silicon steel, reduce iron loss and magnetic anisotropy. In the traditional thick slab continuous casting and thin slab continuous casting and rolling process, since the thickness of the initial cast strip wants to reach the ideal thickness, the reduction rate will be increased, which will lead to <111> / / ND increases, thereby reducing the ideal values ​​of iron loss and magnetic induction. Therefore, it is of great significance to produce non-oriented silicon steel with strong λ texture.

[0004] As a new process, ultra-thin strip-sub-rapid solidification technology has inherent advantages in the production of non-oriented silicon steel. It can be directly solidified into a cast strip of 1 to 5 mm, with excellent initial texture and a short process flow. The thickness advantage directly reduces the hot rolling power, has the advantages of energy saving and emission reduction, and has obvious advantages in forming λ texture. However, there are still problems such as inclusion nodules and weak inheritance of λ texture. Therefore, it is particularly important to reduce inclusions during casting and form a stronger λ texture and retain the texture as much as possible in subsequent processes.

[0005] At present, the production process of non-oriented silicon steel or even non-oriented silicon steel is generally: smelting-casting-hot rolling-normalizing treatment-pickling-cold rolling-annealing; such as the contents disclosed in documents CN114293100A and CN114369761A. Although this technology can obtain products with performance that can meet existing needs, it obviously has problems such as too long process and too high energy consumption.

[0006] In summary, the goal of developing the next generation of non-oriented silicon steel is to produce a steel with a strong λ initial texture and retain as much texture as possible in subsequent processes while meeting the requirements of energy saving, emission reduction, and short process. Summary of the invention

[0007] In order to solve the above-mentioned technical problems, the purpose of the present invention is to provide a method for producing non-oriented silicon steel with a short process and a product having a strong λ texture. The method of the present invention can reduce iron loss and inclusion nodules, reduce energy consumption, and increase the proportion of λ texture in initial and annealed plates.

[0008] In order to achieve the above object, a first aspect of the present invention provides a short-process production method for strong λ texture non-oriented silicon steel, the short-process production method comprising the following steps:

[0009] Step 1:

[0010] Molten steel is smelted according to the set composition, and then the superheat is controlled to cast the strip to obtain a cast strip with a thickness of 1.7 to 2.3 mm. The superheat of the molten steel during casting is 50 to 100°C.

[0011] The chemical composition of molten steel is expressed in mass percentage:

[0012] C: ≤0.003%, Si: 2.0~3.5%, Al: 0.003~0.8%, Mn: 0.2~0.4%, P: 0.003~0.03%, S: 0.001~0.003%, the rest is Fe and unavoidable impurities;

[0013] Step 2:

[0014] The cast strip obtained in step 1 is heated and kept warm, and then hot-rolled in a single pass to obtain a hot-rolled plate with a thickness of 0.54 to 1.26 mm and a reduction rate of 30% to 75%;

[0015] Step 3:

[0016] The hot-rolled sheet obtained in step 2 is cold-rolled to obtain a cold-rolled sheet with a thickness of 0.3 to 0.5 mm;

[0017] Step 4:

[0018] The cold-rolled sheet obtained in step 3 is annealed to obtain a thin strip of strong λ texture non-oriented silicon steel, wherein the annealing temperature is controlled at 950-1050° C. and the holding time is controlled at 3-8 min.

[0019] According to the short-process production method of strong λ texture non-oriented silicon steel of the present invention, preferably, in step 1, the superheat of the molten steel during casting is further controlled to be 50-80°C.

[0020] According to the short-process production method of strong λ texture non-oriented silicon steel of the present invention, preferably, in step 1, the Al element is further fine-tuned and controlled to be 0.003-0.6% by mass.

[0021] According to the short-process production method of strong λ texture non-oriented silicon steel of the present invention, preferably, in step 2, heating and heat preservation are performed followed by hot rolling, wherein the heating temperature is 1100±30° C. and the heat preservation time is 3 to 5 min.

[0022] According to the short-process production method of strong λ texture non-oriented silicon steel of the present invention, preferably, in step 2, the hot rolling temperature is controlled at 700±30 to 1000±30°C.

[0023] According to the short-process production method of strong λ texture non-oriented silicon steel of the present invention, preferably, in step 2, the hot rolling temperature is controlled at 750-950°C.

[0024] According to the short-process production method of strong λ texture non-oriented silicon steel of the present invention, preferably, in step 2, the reduction ratio of hot rolling is further controlled to be 30% to 70%.

[0025] According to the short-process production method of strong λ texture non-oriented silicon steel of the present invention, preferably, in step 2, the reduction ratio of hot rolling is further controlled to be 50% to 70%.

[0026] According to the short-process production method of strong λ texture non-oriented silicon steel of the present invention, preferably, in step 3, the hot-rolled sheet does not need to be normalized, but is directly cold-rolled to a thickness of 0.35-0.5 mm.

[0027] According to the short-process production method of strong λ texture non-oriented silicon steel of the present invention, preferably, in step 4, the annealing temperature is controlled to be 950-1000° C., and the holding time is 4-5 min.

[0028] The second aspect of the present invention further provides a strong λ texture non-oriented silicon steel, wherein the strong λ texture non-oriented silicon steel is produced according to the aforementioned short-process production method.

[0029] According to the strong λ texture non-oriented silicon steel of the present invention, preferably, after step 4, the non-oriented silicon steel annealed sheet is mainly of λ texture, and the λ texture includes Cube texture and rotated Cube texture.

[0030] According to the strong λ texture non-oriented silicon steel of the present invention, preferably, the sum of the volume fractions of the Cube texture and the rotational Cube texture is 20-31%.

[0031] According to the strong λ texture non-oriented silicon steel of the present invention, preferably, after step 4, the longitudinal iron loss value P of the non-oriented silicon steel annealed sheet is 1.0 / 50 At 0.8~1.1W / kg, P 1.5 / 50 Between 1.4 and 2.1 W / kg.

[0032] Beneficial technical effects

[0033] Compared with the prior art, the technical advantages and beneficial technical effects of the present invention are briefly summarized as follows:

[0034] The design idea of ​​the present invention is to reduce inclusion nodules and improve the efficiency of strip formation by regulating the composition of molten steel used in ultra-thin strip continuous casting. Then, based on the ultra-thin strip continuous casting process, a strong λ texture and thin non-oriented silicon steel strip is produced. By regulating the rolling process, the initial λ texture is retained as much as possible, and the λ texture is obtained again by utilizing its nucleation advantage. Finally, through a reasonable annealing process, the nucleation and growth of strong λ texture are realized, and grain growth and homogenization are achieved.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows: by optimizing the composition of molten steel, inclusion nodules are reduced, and at the same time, the strength and proportion of the λ initial texture are improved; in addition, the normalizing process is omitted, and a single-pass hot rolling-cold rolling is directly carried out, which well introduces a deformation band that is beneficial to the nucleation of the subsequent Cube texture, and at the same time retains the λ texture as much as possible, and produces non-oriented silicon steel with a strong λ texture; more importantly, the magnetic properties of the annealed plate non-oriented electrical steel are improved, especially the iron loss is significantly reduced, so that the magnetic property advantages of the non-oriented silicon steel are perfectly reflected. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly introduce the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments. Obviously, the drawings in the following description only relate to some implementation cases of the present invention, and are not intended to limit the present invention.

[0037] Figure 1 The microstructure of the non-oriented silicon steel casting strip produced according to Example 1 of the present invention.

[0038] Figure 2 This is the texture of the non-oriented silicon steel cast strip produced according to Example 1 of the present invention.

[0039] Figure 3 The microstructure of the non-oriented silicon steel annealed sheet produced according to Example 1 of the present invention.

[0040] Figure 4 This is the texture of the non-oriented silicon steel annealed sheet produced according to Example 1 of the present invention.

[0041] Figure 5 This is the microstructure of the non-oriented silicon steel casting strip produced according to Example 3 of the present invention.

[0042] Figure 6 This is the texture of the non-oriented silicon steel cast strip produced according to Example 3 of the present invention.

[0043] Figure 7 This is the microstructure of the non-oriented silicon steel annealed sheet produced according to Example 3 of the present invention.

[0044] Figure 8 This is the texture of the non-oriented silicon steel annealed sheet produced according to Example 3 of the present invention.

[0045] Fig. 9 The microstructure and texture of the non-oriented silicon steel cast strip produced according to Comparative Example 1.

[0046] Fig.10 The microstructure and texture of the non-oriented silicon steel casting strip produced according to Comparative Example 2.

[0047] Fig.11 The microstructure and texture of the non-oriented silicon steel cast strip produced according to Comparative Example 3.

[0048] Fig.12 The microstructure and texture of the non-oriented silicon steel cast strip produced according to Comparative Example 4. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment 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.

[0050] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one of ordinary skill in the art to which the present invention belongs.

[0051] The present invention is based on the ultra-thin strip continuous casting process to produce a 1.7-2.3 mm thick non-oriented silicon steel cast strip by adjusting casting parameters, directly performing single-pass hot rolling and cold rolling to a thickness of 0.35-0.5 mm, and then performing annealing, and this process controls the hot rolling temperature, reduction rate, and annealing temperature and time. Specifically, the production method includes the following steps.

[0052] Step 1: Molten Steel Smelting

[0053] In this step, molten steel is smelted and cast into a casting strip.

[0054] The composition of the molten steel is consistent with that of the cast strip and the final annealed sheet. Specifically, the ultra-thin strip equipment is used for casting, and the chemical composition is:

[0055] C: ≤0.003%, Si: 2.0-3.5%, Al: 0.003-0.8%, Mn: 0.2-0.4%, P: 0.003-0.03%, S: 0.001-0.003%, the rest is Fe and inevitable impurities; the casting strip with a thickness of 1.7-2.3 mm is obtained by using the simulated ultra-thin strip equipment, and the superheat of the molten steel during casting is 50-100°C;

[0056] Step 2: Hot rolling

[0057] In this step, the cast strip obtained in step 1 is uniformly heated and then hot-rolled in a single pass to obtain a hot-rolled plate.

[0058] The hot rolling temperature is controlled at 750±30~950±30℃, and the hot rolled plate is rolled into a thickness of 0.54~1.26mm, and the single pass reduction rate is 30%~70%; the total hot rolling deformation is 30%~70%;

[0059] In this way, by controlling the hot rolling temperature and the hot rolling reduction rate, the grain size, deformation band formation and texture inheritance can be well controlled. In this way, compared with the prior art, hot rolling can better control and facilitate texture inheritance. The hot-rolled plate obtained in this embodiment has excellent texture components and machinability, so as to reduce the difficult-to-roll and unfavorable texture components in the cold rolling process.

[0060] Step 3 Cold rolling

[0061] In this step, the hot-rolled sheet obtained in step 2 is directly cold-rolled.

[0062] The hot-rolled plate obtained in step 2 is cold-rolled to a cold-rolled plate with a thickness of 0.3 to 0.5 mm using a reversible rolling mill; the total deformation amount of the cold-rolling process is 10% to 51% relative to the hot-rolled plate.

[0063] Step 4: Annealing

[0064] In this step, the cold rolled sheet obtained in step 3 is annealed.

[0065] The cold rolled sheet obtained in step 3 is annealed at a temperature of 950-1050° C. and a holding time of 3-8 minutes. By controlling the annealing temperature and annealing time, a good state of organization and texture can be ensured, and the performance of the non-oriented silicon steel annealed sheet can be improved.

[0066] In combination with the above, it can be seen that compared with the prior art, the present implementation method, based on the chemical composition of medium-high silicon content and low aluminum content, combines hot rolling, cold rolling and annealing and other process means. On the one hand, hot rolling is beneficial to texture inheritance and reduces the rolling difficulty of the cold rolling process; on the other hand, the single-pass hot rolling and the entire short process successfully reduce energy consumption, reduce costs, and improve the magnetic properties of the final non-oriented silicon steel, so that the magnetic property advantages of non-oriented electrical steel are perfectly demonstrated.

[0067] In this embodiment, the longitudinal iron loss value P of the non-oriented silicon steel annealed sheet is 1.0 / 50 At 0.8~1.1W / kg, P 1.5 / 50 In the present invention, the iron loss value P 1.0 / 50It is the iron loss per unit weight when the frequency is 50 Hz and the waveform is sinusoidal and the peak value of magnetic induction is 1.0 T. In the present invention, the iron loss value P 1.5 / 50 It is the iron loss per unit weight when the frequency is 50HZ and the waveform is sinusoidal with a peak magnetic induction of 1.5T.

[0068] The following provides embodiments of the present invention to further illustrate the technical solution of the present invention. Of course, these embodiments are only a part of the many variations of the present invention, but not all.

[0069] Example 1

[0070] Provided is a non-oriented silicon steel, which is prepared into an annealed sheet by the following method:

[0071] (1) Molten steel smelting

[0072] The molten steel is cast into a strip, and the chemical composition of the molten steel is (wt%): C0.0015%, Si 3.43%, Al0.6%, Mn0.267%, P≤0.03%, S≤0.003%, and the rest is Fe and inevitable impurities; a 1.8 mm thick cast strip is obtained, the superheat degree of the molten steel during casting is 90°C, the average grain size of the cast strip is 658 μm, and it is mainly composed of λ texture, including {001}<1-30>, {001}<-1-30>, Cube and rotated Cube textures.

[0073] (2) Hot rolling

[0074] The cast strip obtained in step 1 is heated at 1100° C. and then hot rolled at 950° C. with a reduction rate of 50% (ie, the total hot rolling reduction rate is 50%), the rolled thickness is 0.9 mm, and the single-pass reduction rate is 50%.

[0075] (3) Cold rolling

[0076] The hot-rolled sheet obtained in step 2 is cold-rolled to a cold-rolled sheet with a thickness of 0.35 mm using a reversing rolling mill.

[0077] (4) Annealing

[0078] The cold-rolled sheet obtained in step 3 is annealed at a temperature of 1000° C. for a holding time of 4 min, wherein an argon atmosphere is used during the annealing.

[0079] In the present embodiment, the obtained non-oriented silicon steel annealed sheet was subjected to metallographic structure detection and magnetic property detection, and it can be seen that the grain size is uniform, about 130 μm, and has a strong λ texture, including Cube ({001} <010> ), {001}<1-30>, {001}<-1-30> and partially rotated Goss textures ({110} <001> ), the volume fraction of the λ texture component is 30.9%. Longitudinal iron loss value P of non-oriented silicon steel annealed sheet 1.0 / 50 0.8091W / kg, P 1.5 / 50 It is 1.474W / kg.

[0080] Example 2

[0081] Provided is a non-oriented silicon steel, which is prepared into an annealed sheet by the following method:

[0082] (1) Molten steel smelting

[0083] The molten steel is cast into a strip, the chemical composition of the molten steel is (wt%): C 0.0015%, Si 3.43%, Al 0.6%, Mn 0.267%, P ≤ 0.03%, S ≤ 0.003%, and the rest is Fe and inevitable impurities; a 1.8 mm thick cast strip is obtained, and the superheat degree of the molten steel during casting is 90° C.;

[0084] (2) Hot rolling

[0085] The cast strip obtained in step 1 was homogenized at 1100° C., and then hot rolled at 950° C. with a reduction rate of 30% (ie, the total hot rolling reduction rate was 30%), the rolled thickness was 1.26 mm, and the single-pass reduction rate was 30%.

[0086] (3) Cold rolling

[0087] The hot-rolled sheet obtained in step 2 is cold-rolled to a cold-rolled sheet with a thickness of 0.35 mm using a reversing rolling mill.

[0088] (4) Annealing

[0089] The cold-rolled sheet obtained in step 3 is annealed at a temperature of 1000° C. for a holding time of 4 min, wherein an argon atmosphere is used during the annealing.

[0090] In the present embodiment, the obtained non-oriented silicon steel annealed sheet was subjected to metallographic structure detection and magnetic property detection, and it can be seen that the grain size is uniform, about 125 μm, and has a strong λ texture, including Cube ({001} <010> ), {001}<1-40> and {001}<-1-20>, the volume fraction of the λ texture component is 28.8%. Longitudinal iron loss value P of non-oriented silicon steel annealed sheet 1.0 / 50 0.8975W / kg, P1.5 / 50 It is 1.549W / kg.

[0091] Example 3

[0092] Provided is a non-oriented silicon steel, which is prepared into an annealed sheet by the following method:

[0093] (1) Molten steel smelting

[0094] The molten steel is cast into a strip, and the chemical composition of the molten steel is (wt%): C 0.0022%, Si 2.45%, Al0.006%, Mn 0.276%, P≤0.03%, S≤0.003%, and the rest is Fe and inevitable impurities; a 1.8 mm thick cast strip is obtained, the superheat degree of the molten steel during casting is 50°C, the average grain size of the cast strip is 580 μm, and the main texture is λ, which is a rotated Cube texture.

[0095] (2) Hot rolling

[0096] The cast strip obtained in step 1 was uniformly heated at 1100° C., and then hot rolled at 950° C. with a reduction rate of 70% (ie, the total hot rolling reduction rate was 70%), the rolled thickness was 0.54 mm, and the single-pass reduction rate was 35%.

[0097] (3) Cold rolling

[0098] The hot-rolled sheet obtained in step 2 is cold-rolled to a cold-rolled sheet with a thickness of 0.35 mm using a reversing rolling mill.

[0099] (4) Annealing

[0100] The cold-rolled sheet obtained in step 3 is annealed at a temperature of 1000° C. for a holding time of 4 min, wherein an argon atmosphere is used during the annealing.

[0101] In this embodiment, the non-oriented silicon steel annealed sheet is subjected to metallographic structure detection and magnetic property detection, and it can be seen that the grain size is uniform, about 110 μm, and has a strong λ texture, including rotating Cube ({001}<1-10>, {001}<-1-10>), {001}<1-20> and {001}<-1-20>, and the volume fraction of the λ texture component is 23%. The longitudinal iron loss value P of the non-oriented silicon steel annealed sheet is 1.0 / 50 0.9722W / kg, P 1.5 / 50 During the technical development process, it was found that within the composition range defined in the present invention, the content of Si has a significant effect on the iron loss value P of the product. 1.0 / 50 and P 1.5 / 50 There is a certain influence. The basic situation is: the higher the Si content, the lower the iron loss value of the product.

[0102] Example 4

[0103] Provided is a non-oriented silicon steel, which is prepared into an annealed sheet by the following method:

[0104] (1) Molten steel smelting

[0105] Casting the molten steel into a strip, the chemical composition of the molten steel being (wt%): C 0.0022%, Si 2.45%, Al 0.006%, Mn 0.276%, P ≤ 0.03%, S ≤ 0.003%, and the remainder being Fe and unavoidable impurities; obtaining a 1.8 mm thick cast strip, the superheat degree of the molten steel during casting being 50° C.;

[0106] (2) Hot rolling

[0107] The cast strip obtained in step 1 was homogenized at 1100° C., and then hot rolled at 950° C. with a reduction rate of 30% (ie, the total hot rolling reduction rate was 30%), the rolled thickness was 1.26 mm, and the single-pass reduction rate was 30%.

[0108] (3) Cold rolling

[0109] The hot-rolled sheet obtained in step 2 is cold-rolled to a cold-rolled sheet with a thickness of 0.35 mm using a reversing rolling mill.

[0110] (4) Annealing

[0111] The cold-rolled sheet obtained in step 3 is annealed at a temperature of 1000° C. for a holding time of 4 min, wherein an argon atmosphere is used during the annealing.

[0112] In this embodiment, the non-oriented silicon steel annealed sheet obtained is subjected to metallographic structure detection and magnetic property detection, and it can be seen that its grain size is uniform, about 100 μm, and has a strong λ texture, including rotating Cube ({001}<1-10>, {001}<-1-10>), {001}<1-20> and {001}<-1-20>, and the volume fraction of the λ texture component is 26.4%. Non-oriented silicon steel annealed sheet longitudinal iron loss value P 1.0 / 50 0.9831W / kg, P 1.5 / 50 It is 2.0132W / kg.

[0113] Comparative Example 1

[0114] Provided is a non-oriented silicon steel, wherein the non-oriented silicon steel is produced into a cast strip by the following method:

[0115] (1) Molten steel smelting

[0116] The molten steel is cast into a strip, the chemical composition of the molten steel is (wt%): C 0.0015%, Si 3.43%, Al 0.6%, Mn 0.267%, P ≤ 0.03%, S ≤ 0.003%, and the rest is Fe and inevitable impurities; a 1.8 mm thick cast strip is obtained, and the superheat degree of the molten steel during casting is 20° C.;

[0117] (2) In the present embodiment, the obtained non-oriented silicon steel cast strip is subjected to metallographic structure detection and texture characterization, and it can be seen that the grains have more nuclei and are relatively small in size, with an average size of about 400 μm, and a loose texture. In addition to the λ texture, there is also a {11l} texture, and the λ texture strength is relatively weak; this will be detrimental to the subsequent process and the improvement of magnetic properties.

[0118] Comparative Example 2

[0119] Provided is a non-oriented silicon steel, wherein the non-oriented silicon steel is produced into a cast strip by the following method:

[0120] (1) Molten steel smelting

[0121] The molten steel is cast into a strip, the chemical composition of the molten steel is (wt%): C 0.0015%, Si 3.43%, Al 0.6%, Mn 0.267%, P ≤ 0.03%, S ≤ 0.003%, and the rest is Fe and inevitable impurities; a 1.8 mm thick cast strip is obtained, and the superheat degree of the molten steel during casting is 175°C;

[0122] (2) In the present embodiment, the obtained non-oriented silicon steel cast strip is subjected to metallographic structure detection and texture characterization, and it can be seen that the grains have more nuclei and are relatively small in size, with an average size of about 350 μm. The texture is gradually complicated. In addition to the λ texture, there is also a {11l} texture, and the λ texture strength is relatively weak. This will be unfavorable for the subsequent process and the improvement of magnetic properties.

[0123] Comparative Example 3

[0124] Provided is a non-oriented silicon steel, which is prepared into an annealed sheet by the following method:

[0125] (1) Molten steel smelting

[0126] Casting the molten steel into a strip, the chemical composition of the molten steel being (wt%): C 0.0022%, Si 2.45%, Al 0.006%, Mn 0.276%, P ≤ 0.03%, S ≤ 0.003%, and the remainder being Fe and unavoidable impurities; obtaining a 1.8 mm thick cast strip, the superheat degree of the molten steel during casting being 15° C.;

[0127] (2) In the present embodiment, the obtained non-oriented silicon steel cast strip is subjected to metallographic structure detection and texture characterization, and it can be seen that it is mainly composed of equiaxed grains with an average size of about 180 μm, and the texture is extremely scattered, with almost no λ texture formed and the texture strength formed is weak; this will be detrimental to the subsequent process and the improvement of magnetic properties.

[0128] Comparative Example 4

[0129] Provided is a non-oriented silicon steel, which is prepared into an annealed sheet by the following method:

[0130] (1) Molten steel smelting

[0131] The molten steel is cast into a strip, the chemical composition of the molten steel is (wt%): C 0.0022%, Si 2.45%, Al 0.006%, Mn 0.276%, P ≤ 0.03%, S ≤ 0.003%, and the rest is Fe and inevitable impurities; a 1.8 mm thick cast strip is obtained, and the superheat degree of the molten steel during casting is 153° C.;

[0132] (2) In the present embodiment, the obtained non-oriented silicon steel cast strip is subjected to metallographic structure detection and texture characterization. The grains are mainly columnar crystals, but the grain size is uneven, with an average size of about 500 μm, the texture is complex, and no λ texture is formed; this will be detrimental to the subsequent process and the improvement of magnetic properties.

[0133] The above description is only a specific implementation of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A short-process production method for strong λ texture non-oriented silicon steel, characterized in that: The short-process production method comprises the following steps: Step 1: Molten steel is smelted according to the set composition, and then the superheat is controlled to cast the strip to obtain a cast strip with a thickness of 1.7~2.3mm. The superheat of the molten steel during casting is 50~100℃. The chemical composition of molten steel is expressed in mass percentage: C: ≤0.003%, Si: 2.45~3.5%, Al: 0.003~0.8%, Mn: 0.2~0.4%, P: 0.003~0.03%, S: 0.001~0.003%, the rest are Fe and unavoidable impurities; Step 2: The cast strip obtained in step 1 is heated at a temperature of 1100±30°C for a holding time of 3-5 minutes, and then hot-rolled in a single pass to obtain a hot-rolled plate with a thickness of 0.54-1.26 mm, wherein the hot-rolling temperature is controlled at 700-1000°C and the reduction rate is 30%-75%; Step 3: The hot-rolled sheet obtained in step 2 is cold-rolled to obtain a cold-rolled sheet with a thickness of 0.3 to 0.5 mm; Step 4: The cold-rolled sheet obtained in step 3 is annealed to obtain a thin strip of strong λ texture non-oriented silicon steel, wherein the annealing temperature is controlled to be 950-1050° C. and the holding time is controlled to be 3-5 min.

2. The short-process production method of strong λ texture non-oriented silicon steel according to claim 1, characterized in that: In step 1, the superheat of the molten steel during casting is further controlled to be 50~80℃.

3. The short-process production method of strong λ texture non-oriented silicon steel according to claim 1, characterized in that: In step 1, the Al element is further fine-tuned and controlled within a range of 0.003-0.6% by mass.

4. The short-process production method of strong λ texture non-oriented silicon steel according to claim 3, characterized in that: In step 1, the Al element is further fine-tuned and controlled within a range of 0.003-0.006% by mass.

5. The short-process production method of strong λ texture non-oriented silicon steel according to claim 1, characterized in that: In step 2, the hot rolling temperature is controlled at 700-950°C.

6. The short-process production method of strong λ texture non-oriented silicon steel according to claim 5, characterized in that: In step 2, the hot rolling temperature is controlled at 750-950°C.

7. The short-process production method of strong λ texture non-oriented silicon steel according to claim 1, characterized in that: In step 2, the hot rolling reduction rate is further controlled to 30% to 70%.

8. The short-process production method of strong λ texture non-oriented silicon steel according to claim 7, characterized in that: In step 2, the reduction ratio of hot rolling is further controlled to 50% to 70%.

9. The short-process production method of strong λ texture non-oriented silicon steel according to claim 1, characterized in that: In step 3, the hot-rolled plate is directly cold-rolled without normalization to a thickness of 0.35-0.5 mm.

10. The short-process production method of strong λ texture non-oriented silicon steel according to claim 1, characterized in that: In step 4, the annealing temperature is controlled at 950-1000° C., and the holding time is 4-5 min.

11. A strong λ texture non-oriented silicon steel, characterized by: The strong λ texture non-oriented silicon steel is produced according to the short process production method described in any one of claims 1 to 10.

12. The strong λ texture non-oriented silicon steel according to claim 11, characterized in that: After step 4, the non-oriented silicon steel annealed sheet mainly has a λ texture, and the λ texture includes a Cube texture and a rotated Cube texture.

13. The strong λ texture non-oriented silicon steel according to claim 12, characterized in that: The sum of the volume fractions of Cube texture and rotated Cube texture is 20~31%.

14. The strong λ texture non-oriented silicon steel according to any one of claims 11 to 13, characterized in that: After step 4, the longitudinal iron loss value of non-oriented silicon steel annealed sheet P 1.0 / 50 At 0.8~1.1W / kg, P 1.5 / 50 Between 1.4 and 2.1 W / kg.

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