High-magnetic-induction non-oriented silicon steel ultra-thin strip with high content of P and S and preparation method of high-magnetic-induction non-oriented silicon steel ultra-thin strip

Abstract

The invention discloses a non-oriented silicon steel ultra-thin strip with high content of P and S and high magnetic performance. The non-oriented silicon steel ultra-thin strip comprises the following components in percentage by weight: 0.16 to 1.38 percent of P, 0.007 to 0.21 percent of S, 2 to 5 percent of Si, 0.001 to 0.03 percent of Al, not more than 0.02 percent of Mn and the balance of Fe. The production method comprises the following steps: carrying out spray casting and melt spinning under argon pressure during smelting; flattening is conducted; annealing is conducted under the argon protective atmosphere; and cooling to room temperature along with the furnace for later use. On the premise of ensuring that B50 of the non-oriented silicon steel thin strip is larger than or equal to 1.60 T and Pt1.0 / 400 is smaller than or equal to 17.43 W / kg, the non-oriented silicon steel thin strip with better surface quality and more uniform thickness can be obtained by improving the viscosity and fluidity of the melt through P and S elements, and the non-oriented silicon steel thin strip has good machinability in the subsequent process of preparing an iron core in the modes of lamination, welding, tabletting and the like. According to the method, the molten iron pretreatment and RH refining processes are omitted, and the non-oriented silicon steel ultra-thin strip with extremely small thickness and high S and P content can be obtained without hot rolling and cold rolling, so that the consumed time is shortened by not less than 20%, the cost is reduced by at least 30%, the pollution is small, and the operation is easy.

Description

Technical Field

[0001] The invention relates to a non-oriented silicon steel strip and a preparation method thereof, in particular to an extremely thin non-oriented silicon steel strip with high P and S content and high magnetic induction and a preparation method thereof. Background Art

[0002] Silicon steel is a key magnetic material and is indispensable for the manufacture of core components in power equipment. By reducing the thickness of silicon steel sheets, the energy loss caused by eddy currents can be significantly reduced, and the lightweight characteristics of silicon steel strips also meet the market demand for modern magnetic materials for energy conservation, environmental protection, weight reduction, and improved efficiency. However, the traditional process of producing non-oriented silicon steel ultra-thin strips requires multiple rolling and annealing processes to meet the ultra-thin strip thickness requirements. The entire process is cumbersome and the production cycle is extended, resulting in relatively high energy consumption and costs. S and P are common impurity elements in steel. S and P are easily segregated elements. The intergranular segregation of S is easy to form iron sulfide eutectics with a low melting point, resulting in hot brittleness, while the intergranular segregation of P will produce cold brittleness. In order to avoid rolling cracking, the traditional process has extremely strict control over S and P in silicon steel, requiring S not to be higher than 0.005% and P not to be higher than 0.02%, which greatly increases the smelting cost of silicon steel.

[0003] In addition, S and P also have a favorable effect on the magnetic properties of non-oriented silicon steel. The addition of S can optimize the texture of non-oriented silicon steel and increase the magnetic induction. The addition of P can increase the resistivity of non-oriented silicon steel, thereby reducing iron loss under high frequency. And S and P, as surface active elements, can effectively reduce the melting point and melt viscosity of silicon steel and improve the processing formability of thin-gauge non-oriented silicon steel. Compared with traditional processes, the ultra-fast solidification speed of plane flow casting can effectively inhibit the adverse effects of S and P due to segregation, and the addition of S and P can also achieve the optimization of the forming process of plane flow casting silicon steel thin strips. Therefore, the use of plane flow casting technology to prepare high S and high P non-oriented silicon steel ultra-thin strips can obtain excellent magnetic properties while significantly reducing the smelting and rolling costs of silicon steel, which plays an important role in promoting the development of the steel industry.

[0004] After searching:

[0005] The document with Chinese patent publication number CN112846118A discloses "A method for preparing phosphorus-containing silicon steel thin strip with high magnetic properties by strip spinning method". This document only uses single-roller strip spinning technology to prepare non-oriented silicon steel thin strip with high P content, and at the same time improves the resistivity of the thin strip, effectively reducing the iron loss of the thin strip. However, the document does not focus on S.

[0006] The document with Chinese patent publication number CN11814083A discloses "High silicon steel based on trace chromium doping, its ultra-thin strip and preparation method". This document uses rapid solidification technology to make ultra-thin alloy strips. By adding the alloying element chromium, a high silicon steel alloy ultra-thin strip with good surface quality, uniform thickness, good toughness, excellent magnetic properties and corrosion resistance is prepared. However, the composition requirements of the mother alloy are extremely strict, and the content of impurity elements such as P, S, N, and O needs to be controlled within an extremely low range. In addition, the Cr element increases the processing cost of the thin strip, resulting in a complex smelting process for silicon steel thin strips, high cost and energy consumption.

[0007] The document with Chinese patent publication number CN106282501A discloses "A boron-containing high silicon steel strip and its preparation method". This method reduces the melting point of silicon steel by adding boron to the alloy, improves the fluidity of the melt and improves the processing formability, making the molten steel easier to form and less likely to clog the nozzle. However, the addition of B refines the grains inside the organization, resulting in increased hysteresis loss and increased iron loss. In addition, the content of P and S elements is still controlled by complex means during the smelting process of the steel ingot to eliminate their influence on the performance of the silicon steel strip.

[0008] In summary, in the existing processing methods for preparing non-oriented silicon steel thin strips, the requirements for controlling the content of P and S elements are still extremely stringent.

[0009] In the process of preparing non-oriented silicon steel strips by plane flow casting, P and S can reduce the viscosity of the silicon steel melt and improve its fluidity in the plane flow casting process, thereby improving the surface quality of the silicon steel ultra-thin strip and improving its magnetic properties. Moreover, the addition of P and S does not cause high-temperature cracking and cold brittleness of the strip during the strip forming process. Therefore, the non-oriented silicon steel strip with a high content produced by the process prepared by the present invention not only avoids the deterioration of mechanical properties caused by P and S, but also has a favorable effect on the quality and magnetic properties of the strip through the introduction of P and S elements. The process of preparing non-oriented silicon steel strips by this method achieves the optimization of the process flow, reduces processing costs, reduces pollution, and conforms to the green and low-carbon development trend of the steel industry. Summary of the invention

[0010] The present invention aims to overcome the shortcomings of the prior art in the preparation of non-oriented silicon steel, such as the need to strictly control P and S to ensure magnetic properties, resulting in increased production costs, and to provide a non-oriented silicon steel strip with B 50 ≥1.60T, Pt 1.0 / 400Under the premise of ≤17.43W / kg, not only can the improvement of melt viscosity and fluidity by P and S elements be used to obtain non-oriented silicon steel thin strips with better surface quality and more uniform thickness, but also good processability can be achieved in the subsequent process of preparing the iron core by lamination, welding and pressing, so that the production process time can be shortened by no less than 20% and the cost can be reduced by at least 30% to obtain a high P and S content, high magnetic induction non-oriented silicon steel ultra-thin strip and preparation method.

[0011] Measures to achieve the above objectives:

[0012] The invention discloses an extremely thin non-oriented silicon steel strip with high P and S content and high magnetic performance. The components and weight percentage contents thereof are as follows: P: 0.16-1.38%, S: 0.007%-0.21%, Si: 2-5%, Al: 0.001-0.03%, Mn: not more than 0.02%, and the rest being iron and unavoidable impurities.

[0013] Preferably: the weight percentage of each component is: P: 0.21-1.23%, S: 0.009-0.18%, Mn: not more than 0.012%.

[0014] A method for preparing an ultra-thin strip of non-oriented silicon steel with high magnetic properties and high content of P and S, comprising the following steps:

[0015] 1) Smelting: conventionally, pure iron containing not less than 99.96% iron, pure silicon containing not less than 99.96% silicon, ferrophosphorus containing 22-24% phosphorus, and ferrosulphide containing 21-27% sulfur are smelted to a set composition, during which the smelting temperature is controlled at: 1495-1610°C;

[0017] 2) Spray casting under argon pressure, during which: the argon pressure is controlled at 20-45 kPa, the cooling roll is cooled to room temperature at a speed of 8-35 m / s, and the thickness of the strip is controlled not to exceed 150 μm; the nozzle length is controlled at 4-12

[0018] mm, the width of the nozzle does not exceed 3mm;

[0019] 3) Leveling: Control the leveling reduction rate between 2% and 8%;

[0020] 4) Annealing is carried out under argon protective atmosphere, during which: the vacuum degree of the annealing furnace is controlled not to exceed 15Pa, and the annealing temperature is

[0021] 800~1200℃, annealing time is 10~90min;

[0022] 5) Cool to room temperature in the furnace and set aside for use.

[0023] Preferably, the melting temperature is between 1520 and 1580°C.

[0024] Preferably, the argon pressure during the spray casting is 25-35 kPa.

[0025] Preferably, the vacuum degree of the annealing furnace is 8-12 Pa, the annealing temperature is 825-1175° C., and the annealing time is 25-65 min.

[0026] Functions and mechanisms of the components and main processes in the present invention

[0027] P: In non-oriented electrical steel, P is considered to be an important element that affects its performance. In the manufacturing process of traditional thin-gauge non-oriented silicon steel, it is generally believed that the P content can be maintained at no more than 0.1% in the steel to improve mechanical properties and increase resistivity, but too high a P content will cause P to segregate at the grain boundary, thereby increasing the brittleness of the alloy. The addition of P can be increased through the plane casting process, while ensuring solid solution strengthening and resistivity improvement, while avoiding cold brittleness caused by P segregation. At the same time, P optimizes the texture during annealing and improves the magnetic induction of the thin strip. The experimental results show that the best non-oriented silicon steel thin strip can be obtained when the P content is in the range of 0.16% to 1.38%. When the P content is lower than the specified range, it will not affect the viscosity and fluidity of the silicon steel melt, and bonding and uneven thickness are still prone to occur during the thin strip forming process. When the P content is higher than the specified range, a large number of broken strips appear in the finished thin strip. Excessive P content will still cause cold brittleness, and the finished thin strip cannot be used in subsequent processes.

[0028] S: In the manufacturing process of traditional thin-gauge non-oriented silicon steel, S is considered to be a harmful element. Its presence will cause hot brittleness of steel, reduce the mechanical properties of steel, and easily form fibrous MnS precipitates that inhibit grain growth during rolling, resulting in increased iron loss. However, the plane flow casting process directly forms strips without hot rolling, which inhibits the segregation of S and the formation of fibrous MnS precipitation phases. The improvement of the fluidity of the thin strip melt by S significantly optimizes the surface quality of the strip, and S has a beneficial effect on the development of beneficial textures in subsequent annealing, which significantly improves the magnetic induction of the thin strip. The experimental results show that the best non-oriented silicon steel thin strip can be obtained when the S content is in the range of 0.007% to 0.21%. When the S content is lower than the specified range, it cannot affect the silicon steel texture, and the magnetic induction will not be improved accordingly. When the S content is higher than the specified range, a large number of fine precipitation phases such as FeS and MnS will be formed inside the organization, the grains will be refined, and the movement of magnetic domains will be strongly hindered, resulting in an increase in iron loss.

[0029] Si: Si is the main alloying element in non-oriented silicon steel. The improvement of Si on resistivity can greatly reduce induced eddy currents and reduce eddy current losses of silicon steel. In addition, Si can reduce magnetic aging, increase magnetic induction intensity, and optimize the magnetic properties of silicon steel. However, too high Si content will lead to the appearance of ordered phases inside the organization, resulting in increased alloy brittleness of silicon steel and deterioration of processing performance. Experimental results show that non-oriented silicon steel strips with excellent magnetic properties can be obtained when the Si content is in the range of 2% to 5%. When the Si content is lower than the specified range, the improvement of the resistivity and saturation magnetic induction intensity of silicon steel is small, and the Si action mechanism is not significant. When the Si content is higher than the specified range, the brittleness of the finished strip will increase due to the generation of ordered phases, which is not conducive to subsequent processing and use.

[0030] The reason why the present invention controls the Al content range to be: 0.001% to 0.03% is that Al content higher than this content will cause nozzle clogging during the process of metal melt spraying to the cooling roller, affecting the quality of the strip, and limiting the Al content to below 0.001% will bring great difficulties in ingot melting due to the excessively high requirements for element content control.

[0031] The present invention controls the Mn content to be no more than 0.02%. Mn above this limited range will result in the formation of fine MnS precipitation phases inside the ribbon structure under ultra-fast cooling rate, which will hinder the movement of magnetic domains and deteriorate the magnetic properties of the ribbon.

[0032] The reason why the present invention controls the melting temperature range to be: 1495~1610℃, preferably the melting temperature is 1520~1580℃, is because this can ensure the complete melting of the experimental materials, thereby promoting the uniform distribution of the components. This uniform mixing plays a decisive role in accurately controlling the content of each component in the sample.

[0033] The reason why the present invention controls the argon flow rate range to be 0.05-0.15 L / min is that excessive gas flow rate will increase costs. Therefore, under the premise of ensuring that the argon environment is fully filled, protecting the gas within this flow range can effectively avoid oxidation during the cooling process of silicon steel.

[0034] The reason why the induction heating temperature range is controlled to be 1450-1550°C and argon protection is used throughout the process is that P and S effectively reduce the melting point of silicon steel. Heating within this temperature range can ensure that the melt is sprayed out at a certain superheat at a lower spray casting temperature. Under the protection of argon, uneven surface oxidation of the thin strip during cooling is avoided, and the surface quality of the thin strip is optimized.

[0035] The reason why the present invention controls the argon pressure at 20-45 kPa, cools to room temperature at a cooling roller speed of 8-35 m / s, and controls the casting strip thickness not to exceed 150 μm is that within this pressure range, the melt can quickly pass through the nozzle and uniformly contact the surface of the copper roller to complete instantaneous cooling, and the casting strip thickness within the roller speed range is uniform and less than 150 μm, which effectively reduces eddy current loss.

[0036] The reason why the flattening reduction ratio is controlled within the range of 2-8% in the present invention is that the surface can be initially flattened within this reduction ratio, the uniformity of thickness can be improved, and a prerequisite is provided for the development of a favorable texture in subsequent annealing.

[0037] The reason why the vacuum degree of the annealing furnace is controlled not to exceed 15Pa, the annealing temperature is 800-1100°C, and the annealing time is 10-90min is that the low negative pressure state can make the instrument more airtight and has no effect on the strip throwing process. Annealing within this temperature and time range can provide sufficient power for grain growth and effectively reduce dislocation density, reduce thin strip hysteresis loss, and optimize magnetic properties.

[0038] Compared with the prior art, the present invention ensures the B 50 ≥1.60T, Pt 1.0 / 400 Under the premise of ≤17.43W / kg, not only can the improvement of melt viscosity and fluidity by P and S elements be used to obtain non-oriented silicon steel strips with better surface quality and more uniform thickness, but also good processability can be achieved in the subsequent preparation of iron cores by lamination, welding and pressing. The present invention eliminates the process of desulfurization and dephosphorization by pretreatment of molten iron and RH refining in the traditional process, and can obtain non-oriented silicon steel ultra-thin strips with extremely small thickness and high S and P content without hot rolling and cold rolling, shortening the time consumption by no less than 20%, reducing the cost by at least 30%, with less pollution, easy operation and excellent finished product performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The non-oriented silicon steel ultra-thin strip with high P and S content prepared in the embodiment of the present invention;

[0040] Figure 2 This is a SEM image of the surface morphology of the ultra-thin strip of non-oriented silicon steel with high P and S content of the present invention;

[0041] Figure 3 This is the EBSD analysis diagram of the free surface of the ultra-thin strip of non-oriented silicon steel with high P and S content of the present invention;

[0042] Figure 4 The invention discloses a sample ring for detecting magnetic properties of an extremely thin strip of non-oriented silicon steel with high P and S contents. DETAILED DESCRIPTION

[0043] The present invention is described in detail below:

[0044] Example 1

[0045] A high-magnetic non-oriented silicon steel ultra-thin strip with high content of P and S, the components and weight percentages of which are: P: 0.16%, S: 0.008%, Si: 2.5%, Al: 0.005%, Mn: 0.002%, and the rest are iron and unavoidable impurities;

[0046] Production method:

[0047] A method for preparing an ultra-thin strip of non-oriented silicon steel with high magnetic properties and high content of P and S, comprising the following steps:

[0048] 1) Smelting: according to the routine, pure iron containing not less than 99.96% of iron, pure silicon containing not less than 99.96% of silicon, ferrophosphorus containing 22.4% of phosphorus, and ferrosulphide containing 21.2% of sulfur are placed in a quartz crucible with a nozzle at the bottom and smelted to a set composition, wherein the smelting temperature is 1525°C;

[0049] 2) Spray casting and strip casting are carried out under argon pressure, during which: the argon pressure is controlled at 27kPa and the cooling roller speed is

[0050] Cool to room temperature at 8m / s, and control the belt thickness to 150μm; control the nozzle length to 10mm, and the nozzle width to 3mm;

[0051] 3) Leveling: Control the leveling reduction rate within 3%;

[0052] 4) Annealing is performed under an argon protective atmosphere, during which: the vacuum degree of the annealing furnace is controlled to be 8Pa, the annealing temperature is 852°C, and the annealing time is 15min;

[0053] 5) Cool to room temperature in the furnace and set aside for use.

[0054] After testing and statistics, the magnetic properties of the thin strip produced are: B 50 =1.62T,Pt 1.0 / 400 =16.94W / kg, saving 36% of the desulfurization process time compared with the existing technology, and reducing the raw material and processing costs of steel ingot smelting by 41%.

[0055] Note: In this embodiment and the following embodiments, the raw materials are placed in a quartz crucible, which is then placed in a vacuum induction furnace for smelting, and then cooled and solidified into an ingot; the ingot is then cut into blocks, high-frequency heated, and then spray-casted and thrown to the product thickness.

[0056] Example 2

[0057] A high-magnetic non-oriented silicon steel ultra-thin strip with high content of P and S, the components and weight percentages of which are: P: 0.32%, S: 0.013%, Si: 3.1%, Al: 0.011%, Mn: 0.007%, and the rest are iron and unavoidable impurities;

[0058] Production method:

[0059] A method for preparing an ultra-thin strip of non-oriented silicon steel with high magnetic properties and high content of P and S, comprising the following steps:

[0060] 1) Smelting: according to the routine, pure iron containing not less than 99.98% of iron, pure silicon containing not less than 99.97% of silicon, ferrophosphorus containing 21.7% of phosphorus, and ferrosulphide containing 22.1% of sulfur are put into a quartz crucible and smelted to a set composition, during which the smelting temperature is 1537° C.;

[0061] 2) Spray casting and strip casting were carried out under argon pressure, during which: the argon pressure was controlled at 29 kPa and the cooling roller speed was

[0062] Cool to room temperature at 12 m / s, and control the belt thickness to 140 μm; control the nozzle length to 10 mm, and the nozzle width to 3 mm;

[0063] 3) Leveling: Control the leveling reduction rate to be within 3.3%;

[0064] 4) Annealing is performed under an argon protective atmosphere, during which: the vacuum degree of the annealing furnace is controlled at 10 Pa, the annealing temperature is at 893° C., and the annealing time is at 21 min;

[0065] 5) Cool to room temperature in the furnace and set aside for use.

[0066] After testing and statistics, the magnetic properties of the thin strip produced are: B 50 =1.61T,Pt 1.0 / 400 =16.87W / kg, saving 38% of the desulfurization process time compared with the existing technology, and reducing the raw material and processing costs of steel ingot smelting by 43%.

[0067] Example 3

[0068] A high-magnetic non-oriented silicon steel ultra-thin strip with high content of P and S, the components and weight percentages of which are: P: 0.61%, S: 0.017%, Si: 3.3%, Al: 0.016%, Mn: 0.011%, and the rest are iron and inevitable impurities;

[0069] Production method:

[0070] A method for preparing an ultra-thin strip of non-oriented silicon steel with high magnetic properties and high content of P and S, comprising the following steps:

[0071] 1) Smelting: according to the routine, pure iron containing not less than 99.99% of iron, pure silicon containing not less than 99.98% of silicon, ferrophosphorus containing 22.6% of phosphorus, and ferrosulphide containing 22.5% of sulfur are put into a quartz crucible and smelted to a set composition, during which the smelting temperature is 1546° C.;

[0072] 2) Spray casting and strip casting were carried out under argon pressure, during which: the argon pressure was controlled at 31.3 kPa and the cooling roller speed was

[0073] Cool to room temperature at 16.7 m / s, and control the strip thickness to 134 μm; control the nozzle length to 10 mm, and the nozzle width to 3 mm;

[0074] 3) Leveling: Control the leveling reduction rate to be within 3.7%;

[0075] 4) Annealing is performed under an argon protective atmosphere, during which: the vacuum degree of the annealing furnace is controlled at 13.2 Pa, the annealing temperature is at 941° C., and the annealing time is 33 min;

[0076] 5) Cool to room temperature in the furnace and set aside for use.

[0077] After testing and statistics, the magnetic properties of the thin strip produced are: B 50 =1.627T,Pt 1.0 / 400 =16.512W / kg, saving 40.2% of the desulfurization process time compared with the existing technology, and reducing the raw material and processing costs of steel ingot smelting by 44.5%.

[0078] Example 4

[0079] A high-magnetic non-oriented silicon steel ultra-thin strip with high content of P and S, the components and weight percentages of which are: P: 0.82%, S: 0.018%, Si: 3.5%, Al: 0.019%, Mn: 0.014%, and the rest are iron and unavoidable impurities;

[0080] Production method:

[0081] A method for preparing an ultra-thin strip of non-oriented silicon steel with high magnetic properties and high content of P and S, comprising the following steps:

[0082] 1) Smelting: according to the routine, pure iron containing not less than 99.96% of iron, pure silicon containing not less than 99.96% of silicon, ferrophosphorus containing 23.1% of phosphorus, and ferrosulphide containing 22.6% of sulfur are put into a quartz crucible and smelted to a set composition, wherein the smelting temperature is 1562° C.;

[0083] 2) Spray casting and strip casting were carried out under argon pressure, during which: the argon pressure was controlled at 33 kPa and the cooling roller speed was 21.4

[0084] m / s to cool to room temperature, and control the strip thickness to be 122μm; control the nozzle length to be 10mm, and the nozzle width to be 3mm;

[0085] 3) Leveling: Control the leveling reduction rate to be within 4.1%;

[0086] 4) Annealing is performed under an argon protective atmosphere, during which: the vacuum degree of the annealing furnace is controlled at 14.7 Pa, the annealing temperature is at 993° C., and the annealing time is at 46 min;

[0087] 5) Cool to room temperature in the furnace and set aside for use.

[0088] After testing and statistics, the magnetic properties of the thin strip produced are: B 50 =1.64T,Pt 1.0 / 400 =16.11W / kg, saving 41.6% of the desulfurization process time compared with the existing technology, and reducing the raw material and processing costs of steel ingot smelting by 45.2%.

[0089] Example 5

[0090] A high-magnetic non-oriented silicon steel ultra-thin strip with high content of P and S, the components and weight percentages of which are: P: 0.93%, S: 0.021%, Si: 4.2%, Al: 0.024%, Mn: 0.017%, and the rest are iron and unavoidable impurities;

[0091] Production method:

[0092] A method for preparing an ultra-thin strip of non-oriented silicon steel with high magnetic properties and high content of P and S, comprising the following steps:

[0093] 1) Smelting: according to the conventional method, pure iron containing not less than 99.97% of iron, pure silicon containing not less than 99.98% of silicon, ferrophosphorus containing 21.4% of phosphorus, and ferrosulphide containing 21.8% of sulfur are put into a quartz crucible and smelted to a set composition, wherein the smelting temperature is 1575° C.;

[0094] 2) Spray casting and strip casting were carried out under argon pressure, during which: the argon pressure was controlled at 37 kPa and the cooling roller speed was

[0095] Cool to room temperature at 25.8 m / s, and control the belt thickness to 110 μm; control the nozzle length to 10 mm, and the nozzle width to 3 mm;

[0096] 3) Leveling: Control the leveling reduction rate to be within 4.6%;

[0097] 4) Annealing is performed under an argon protective atmosphere, during which: the vacuum degree of the annealing furnace is controlled at 14.9 Pa, the annealing temperature is at 1055° C., and the annealing time is 65 min;

[0098] 5) Cool to room temperature in the furnace and set aside for use.

[0099] After testing and statistics, the magnetic properties of the thin strip produced are: B 50 =1.63T,Pt 1.0 / 400 =16.06W / kg, saving 41.9% of the desulfurization process time compared with the existing technology, and reducing the raw material and processing costs of steel ingot smelting by 45.7%.

[0100] This specific implementation is only the best example and is not a restrictive implementation of the technical solution of the present invention.

Claims

1. A high-magnetic non-oriented silicon steel ultra-thin strip with high content of P and S, the components and weight percentages of which are: P: 0.16~1.38%, S: 0.007%~0.21%, Si: 2~5%, Al: 0.001~0.03%, Mn: not more than 0.02%, and the rest are iron and unavoidable impurities.

2. The ultra-thin strip of non-oriented silicon steel with high P and S content and high magnetic properties as claimed in claim 1, characterized in that: The weight percentage of each component is: P: 0.21% to 1.23%, S: 0.009 to 0.18%, and Mn: not more than 0.012%.

3. The method for preparing a high-magnetic non-oriented silicon steel ultra-thin strip with high P and S content as claimed in claim 1, comprising the following steps: 1) Smelting: conventionally, pure iron containing not less than 99.96% iron, pure silicon containing not less than 99.96% silicon, ferrophosphorus containing 22-24% phosphorus, and ferrosulphide containing 21-27% sulfur are smelted to a set composition, during which the smelting temperature is controlled at: 1495-1610°C; 2) Spray casting under argon pressure, during which: the argon pressure is controlled at 20-45 kPa, the cooling roll is cooled to room temperature at a speed of 8-35 m / s, and the thickness of the strip is controlled not to exceed 150 μm; the nozzle length is controlled at 4-12 mm, the width of the nozzle does not exceed 3mm; 3) Leveling: Control the leveling reduction rate between 2% and 8%; 4) Annealing is carried out under argon protective atmosphere, during which: the vacuum degree of the annealing furnace is controlled not to exceed 15Pa, and the annealing temperature is 800~1200℃, annealing time is 10~90min; 5) Cool to room temperature in the furnace and set aside for use.

4. The method for preparing a high-P and high-S content high-magnetic non-oriented silicon steel ultra-thin strip according to claim 3, characterized in that: The melting temperature is between 1520 and 1580°C.

5. The method for preparing a high-P and high-S content high-magnetic non-oriented silicon steel ultra-thin strip according to claim 3, characterized in that: The argon pressure during the spray casting is 25-35 kPa.

6. The method for preparing a high-P and high-S content high-magnetic non-oriented silicon steel ultra-thin strip according to claim 3, characterized in that: The vacuum degree of the annealing furnace is 8-12 Pa, the annealing temperature is 825-1175° C., and the annealing time is 25-65 min.

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