Heat treatment method for rapidly solidifying high silicon steel ultrathin strip and ultrathin strip

Abstract

The invention provides a heat treatment method for rapidly solidifying a high-silicon steel ultrathin strip, which comprises the following steps: providing a high-silicon steel ultrathin strip prepared by rapid solidification, and coiling the ultrathin strip into a strip coil stock, so that a certain gap exists between the strip coil stock layers; the strip coil stock is placed in a heat treatment furnace pipe in a room temperature state, and then the heat treatment furnace pipe is treated till the pressure of the heat treatment furnace pipe is smaller than a preset pressure value; heating the heat treatment furnace pipe according to a preset heating rate until the temperature in the heat treatment furnace pipe reaches a first preset temperature value, and then stopping vacuumizing; and carrying out heat preservation treatment on the strip coil material in the heat treatment furnace pipe for preset time, and then carrying out furnace cooling on the strip coil material until the temperature in the heat treatment furnace pipe is smaller than a second preset temperature value, so as to obtain the ultrathin strip after heat treatment. The problem that in the prior art, the strip performance is affected by a heat treatment mode of ultrathin high silicon steel prepared through a rapid solidification method is solved.

Description

Technical Field

[0001] The invention relates to the technical field of strip manufacturing, and in particular to a heat treatment method for a rapidly solidified high-silicon steel ultra-thin strip and the ultra-thin strip. Background Art

[0002] The ultra-thin high silicon steel (Fe-6.5wt.%Si) strip (thickness about 0.035mm) produced by rapid solidification method has too fine grains and too large internal stress due to its too fast cooling speed, which eventually leads to a certain gap between the magnetic properties and the theoretical value. Therefore, it is necessary to heat treat it to make its grains grow, reduce its internal stress, and restore its magnetic properties.

[0003] At present, ultra-thin high-silicon steel strips are generally treated in a heat treatment method similar to that of traditional silicon steel. Before heat treatment, a layer of magnesium oxide is first coated on the surface of the strip as an isolation layer to prevent adhesion between the strip layers, and the residual magnesium oxide is cleaned after heat treatment. This method is not only complicated and costly, but also magnesium oxide reacts with silicon in the strip to a certain extent at high temperatures, affecting the performance of the strip. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a heat treatment method for rapidly solidified high-silicon steel ultra-thin strip, aiming to solve the problem in the prior art that the heat treatment method of ultra-thin high-silicon steel produced by rapid solidification method affects the strip performance.

[0005] The embodiment of the present invention is implemented as follows:

[0006] A heat treatment method for rapidly solidified high silicon steel ultra-thin strip, characterized in that the method comprises:

[0007] Providing a high silicon steel ultra-thin strip made by rapid solidification, and rolling the ultra-thin strip into a strip coil so that there is a certain gap between the strip coil layers;

[0008] Placing the strip coil in a heat treatment furnace at room temperature, and then treating the heat treatment furnace until the pressure of the heat treatment furnace is less than a preset pressure value;

[0009] The heat treatment furnace is heated at a preset heating rate until the temperature inside the heat treatment furnace reaches a first preset temperature value and then vacuuming is stopped;

[0010] The strip coil is subjected to heat preservation treatment in the heat treatment furnace for a preset time, and then the strip coil is cooled with the furnace until the temperature in the heat treatment furnace is less than a second preset temperature value to obtain a heat-treated ultra-thin strip.

[0011] Furthermore, in the above-mentioned heat treatment method for rapidly solidified high-silicon steel ultra-thin strip, the lamination coefficient of the strip coil is 0.75 to 0.85.

[0012] Furthermore, in the above-mentioned heat treatment method for rapidly solidified high-silicon steel ultra-thin strip, the preset pressure value is 100Pa.

[0013] Furthermore, in the above-mentioned heat treatment method for rapidly solidified high-silicon steel ultra-thin strip, the preset heating rate is less than 5°C / min.

[0014] Furthermore, in the above-mentioned heat treatment method for rapidly solidified high-silicon steel ultra-thin strip, the first preset temperature value is 800°C to 900°C.

[0015] Furthermore, in the above-mentioned heat treatment method for rapidly solidified high-silicon steel ultra-thin strip, the insulation treatment time is 1.5 hours to 3 hours.

[0016] Furthermore, in the above-mentioned heat treatment method for rapidly solidified high-silicon steel ultra-thin strip, the second preset temperature value is 100°C.

[0017] Furthermore, in the above-mentioned heat treatment method for rapidly solidified high silicon steel ultra-thin strip, the steps of placing the strip coil in a heat treatment furnace at room temperature and then treating the heat treatment furnace until the pressure of the heat treatment furnace is less than a preset pressure value include:

[0018] The strip coil is placed in a heat treatment furnace at room temperature, and then the heat treatment furnace is evacuated or filled with protective gas until the pressure of the heat treatment furnace is less than a preset pressure value.

[0019] Furthermore, in the above-mentioned heat treatment method for rapidly solidified high-silicon steel ultra-thin strip, the protective gas is high-purity argon.

[0020] Another object of the present invention is to provide a rapidly solidified high silicon steel ultra-thin strip, which is obtained by heat treatment using the above-mentioned heat treatment method for rapidly solidified high silicon steel ultra-thin strip.

[0021] Compared with the prior art: the embodiment of the present invention adopts the method of providing an ultra-thin strip of high silicon steel made by rapid solidification, and rolling the ultra-thin strip into a strip coil so that there is a certain gap between the strip coil layers; placing the strip coil in a heat treatment furnace at room temperature, and then treating the heat treatment furnace until the pressure of the heat treatment furnace is less than a preset pressure value; heating the heat treatment furnace at a preset heating rate until the temperature in the heat treatment furnace reaches a first preset temperature value and then stopping vacuuming; heat-treating the strip coil in the heat treatment furnace for a preset time, and then cooling the strip coil with the furnace until the temperature in the heat treatment furnace is less than a second preset temperature value to obtain a heat-treated ultra-thin strip, wherein there is no need to first coat a layer of magnesium oxide on the surface of the strip as an isolation layer to prevent adhesion between the strip layers, and to avoid a certain degree of reaction between magnesium oxide and silicon in the strip at high temperature, which affects the performance of the strip. The problem that the heat treatment method of ultra-thin high silicon steel made by rapid solidification in the prior art affects the performance of the strip is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flow chart of a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in one embodiment of the present invention;

[0023] Figure 2 The microstructure diagram of the ultra-thin strip prepared at a heat treatment temperature of 400° C. in the heat treatment method for the rapid solidification high-silicon steel ultra-thin strip proposed in one embodiment of the present invention;

[0024] Figure 3 The microstructure diagram of the ultra-thin strip prepared at a heat treatment temperature of 500° C. in the heat treatment method for the rapid solidification high-silicon steel ultra-thin strip proposed in one embodiment of the present invention;

[0025] Figure 4 This is a microstructure diagram of an ultra-thin strip prepared at a heat treatment temperature of 600° C. in a heat treatment method for a rapidly solidified high-silicon steel ultra-thin strip proposed in an embodiment of the present invention;

[0026] Figure 5 The microstructure diagram of the ultra-thin strip prepared at a heat treatment temperature of 700° C. in the heat treatment method for the rapidly solidified high-silicon steel ultra-thin strip proposed in one embodiment of the present invention;

[0027] Figure 6 The microstructure diagram of the ultra-thin strip prepared at a heat treatment temperature of 800° C. in the heat treatment method for the rapidly solidified high-silicon steel ultra-thin strip proposed in one embodiment of the present invention;

[0028] Figure 7 This is a microstructure diagram of an ultra-thin strip prepared at a heat treatment temperature of 900° C. in a heat treatment method for a rapidly solidified high-silicon steel ultra-thin strip proposed in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0031] In addition, the term "and / or" as used herein includes any and all combinations of one or more related listed items. In the detailed description and claims, a list of items connected by the term "one of" may mean any of the listed items. For example, if items A and B are listed, the phrase "one of A and B" means only A or only B. In another example, if items A, B, and C are listed, the phrase "one of A, B, and C" means only A; only B; or only C. Item A may contain a single element or multiple elements. Item B may contain a single element or multiple elements. Item C may contain a single element or multiple elements. In the detailed description and claims, a list of items connected by the terms "at least one of", "at least one of" or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, the phrase "at least one of A and B" or "at least one of A or B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, the phrase "at least one of A, B, and C" or "at least one of A, B, or C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may include a single element or multiple elements. Item B may include a single element or multiple elements. Item C may include a single element or multiple elements.

[0032] The present invention aims to solve the problem that the heat treatment method of ultra-thin high silicon steel produced by rapid solidification method affects the performance of the strip, and proposes a heat treatment method for ultra-thin strip of rapid solidification high silicon steel. Figure 1 , wherein the method comprises:

[0033] Step S10, providing an ultra-thin strip of high silicon steel made by rapid solidification, and rolling the ultra-thin strip into a strip coil, so that there is a certain gap between the layers of the strip coil;

[0034] Step 11, placing the strip coil in a heat treatment furnace at room temperature, and then treating the heat treatment furnace until the pressure of the heat treatment furnace is less than a preset pressure value;

[0035] Step S12, heating the heat treatment furnace according to a preset heating rate until the temperature inside the heat treatment furnace reaches a first preset temperature value and then stopping vacuuming;

[0036] Step S13, heat-insulating the strip coil in the heat treatment furnace for a preset time, and then cooling the strip coil with the furnace until the temperature in the heat treatment furnace is less than a second preset temperature value to obtain a heat-treated ultra-thin strip.

[0037] The strip is rolled into a coil so that there is a certain gap between the layers, and the stacking coefficient (filling coefficient) is 0.75-0.85. If the stacking coefficient is too high, it is easy to cause adhesion between the layers, and if it is too low, it is easy to cause unevenness. When the temperature in the heat treatment furnace is room temperature, the strip coil is placed in the furnace, and the heat treatment furnace is evacuated or filled with protective gas, such as high-purity argon. When the strip is placed in the air, the surface of the strip is prone to severe oxidation. When the pressure in the furnace is less than 100Pa, the power is turned on for heating, and the heating rate is less than 5℃ / min. The heating rate in the furnace is too high, which makes the internal stress of the strip unevenly released, so that the strip plate shape becomes uneven. For example, when the temperature in the furnace reaches 800-900℃, stop evacuating and start keeping warm for 1.5-3 hours. When the keeping warm time is reached, disconnect the heating power supply and stop heating. The strip coils cool with the furnace. The stress generated inside the strip varies with the cooling speed. Due to the existence of internal stress, the magnetic domain reversal is affected, thereby affecting the magnetic properties of the strip. When the temperature in the furnace is less than 100℃, air is introduced into the furnace. When the air pressure inside and outside the furnace is the same, open the furnace door, and the strip coils are taken out of the furnace to complete the heat treatment process.

[0038] On the other hand, the present invention further provides a rapidly solidified high silicon steel ultra-thin strip, which is obtained by heat treatment using the above-mentioned heat treatment method for rapidly solidified high silicon steel ultra-thin strip.

[0039] In order to facilitate understanding of the present invention, several embodiments of the present invention are provided below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0040] Example 1

[0041] Providing ultra-thin strips of high silicon steel made by rapid solidification, and rolling the ultra-thin strips into strip coils, wherein the lamination factor is 0.8, so that there is a certain gap between the layers of the strip coils;

[0042] The strip coil is placed in a heat treatment furnace at room temperature, and then the heat treatment furnace is vacuum treated until the pressure of the heat treatment furnace is less than 100 Pa;

[0043] The heat treatment furnace is heated at a heating rate of 5°C / min until the temperature inside the heat treatment furnace reaches 900°C, and then vacuuming is stopped;

[0044] The strip coil is subjected to insulation treatment in the heat treatment furnace for 1.5 hours, and then the strip coil is cooled along with the furnace until the temperature in the heat treatment furnace is less than 100° C., thereby obtaining a heat-treated ultra-thin strip.

[0045] Example 2

[0046] This embodiment also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this embodiment and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0047] The stacking coefficient is 0.7, the heat treatment temperature is 700℃, and the holding time is 3h.

[0048] Example 3

[0049] This embodiment also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this embodiment and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0050] The stacking coefficient is 0.8, the heat treatment temperature is 700℃, and the holding time is 3h.

[0051] Example 4

[0052] This embodiment also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this embodiment and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0053] The stacking coefficient is 0.9, the heat treatment temperature is 700℃, and the holding time is 3h.

[0054] Example 5

[0055] This embodiment also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this embodiment and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0056] The stacking coefficient is 0.7, the heat treatment temperature is 800℃, and the holding time is 3h.

[0057] Example 6

[0058] This embodiment also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this embodiment and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0059] The stacking coefficient is 0.8, the heat treatment temperature is 700℃, and the holding time is 3h.

[0060] Example 7

[0061] This embodiment also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this embodiment and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0062] The stacking coefficient is 0.9, the heat treatment temperature is 800℃, and the holding time is 3h.

[0063] Example 8

[0064] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0065] The stacking coefficient is 0.7 and the insulation time is 1.5h.

[0066] Example 9

[0067] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0068] The stacking coefficient is 0.7 and the insulation time is 2h.

[0069] Example 10

[0070] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0071] The stacking coefficient is 0.7 and the insulation time is 3h.

[0072] Embodiment 11

[0073] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0074] The stacking coefficient is 0.8 and the insulation time is 2h.

[0075] Example 12

[0076] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0077] The stacking coefficient is 0.8 and the insulation time is 3h.

[0078] Example 13

[0079] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0080] The stacking coefficient is 0.9 and the insulation time is 1.5h.

[0081] Embodiment 14

[0082] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0083] The stacking coefficient is 0.9 and the insulation time is 2h.

[0084] Embodiment 15

[0085] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0086] The lamination coefficient is 0.9 and the insulation time is 3h.

[0087] Example 16

[0088] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0089] The heating rate was 10°C / min.

[0090] Embodiment 17

[0091] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0092] The heating rate was 20°C / min.

[0093] Embodiment 18

[0094] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0095] The cooling method is open-cover cooling.

[0096] Embodiment 19

[0097] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0098] The cooling method is to open the cover and blow air to cool.

[0099] Embodiment 20

[0100] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0101] The stacking coefficient is 0.7, the heat treatment temperature is 400℃, and the holding time is 3h.

[0102] Embodiment 21

[0103] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0104] The stacking coefficient is 0.7, the heat treatment temperature is 500°C, and the holding time is 3h.

[0105] Embodiment 22

[0106] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0107] The stacking coefficient is 0.7, the heat treatment temperature is 600℃, and the holding time is 3h.

[0108] Embodiment 23

[0109] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0110] The stacking coefficient is 0.8, the heat treatment temperature is 400°C, and the holding time is 3h.

[0111] Embodiment 24

[0112] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0113] The stacking coefficient is 0.8, the heat treatment temperature is 500°C, and the holding time is 3h.

[0114] Embodiment 25

[0115] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0116] The stacking coefficient is 0.8, the heat treatment temperature is 600℃, and the holding time is 3h.

[0117] Embodiment 26

[0118] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0119] The stacking coefficient is 0.9, the heat treatment temperature is 400°C, and the holding time is 3h.

[0120] Embodiment 27

[0121] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0122] The stacking coefficient is 0.9, the heat treatment temperature is 500°C, and the holding time is 3h.

[0123] Embodiment 28

[0124] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0125] The stacking coefficient is 0.9, the heat treatment temperature is 600℃, and the holding time is 3h.

[0126] Embodiment 29

[0127] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0128] Air is introduced during heat treatment.

[0129] Embodiment 30

[0130] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0131] High purity argon gas is introduced during heat treatment.

[0132] Embodiment 31

[0133] This comparative example also proposes a heat treatment method for a rapidly solidified high silicon steel ultra-thin strip. The difference between the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in this comparative example and the heat treatment method for a rapidly solidified high silicon steel ultra-thin strip proposed in Example 1 is that:

[0134] Industrial argon gas was introduced during heat treatment.

[0135] Please refer to the following Table 1, which shows the parameters corresponding to the above embodiments 1-31 of the present invention. As shown in the following Table 1, it should be noted that in order to ensure the accuracy of the experiment, the other process parameters in the above embodiments are consistent.

[0136] Table 1

[0137]

[0138]

[0139] Also, see Figures 2 to 7 , which is the organizational diagram of the high silicon steel thin strip prepared at different heat treatment temperatures in the embodiments of the present invention, specifically, the organizational diagram of the high silicon steel thin strip prepared under the conditions of stacking factor of 0.8, holding temperature of 400-800°C, holding time of 3 hours, heating rate of 5°C / minute, strip environment of vacuum, and cooling method of furnace cooling, and the organizational diagram of the high silicon steel thin strip prepared under the conditions of stacking factor of 0.8, holding temperature of 900°C, holding time of 1.5 hours, heating rate of 5°C / minute, strip environment of vacuum, and cooling method of furnace cooling.

[0140] It can be clearly seen that after the heat treatment under low temperature conditions, there is no obvious change in the grain size of the strip, and there is no adhesion between the layers of the strip coil, that is, there is no obvious migration of atoms between the strip layers at low temperature. In addition, in combination with Examples 20 to 28, the iron loss P, coercive force and relative magnetic permeability are analyzed, and the magnetic performance indicators are almost the same, maintaining the iron loss P at 23W / Kg (400Hz1000mT), the coercive force Hc at 124A / m, and the relative magnetic permeability at a level of only 3000.

[0141] It can be clearly seen from Examples 2 to 4 that during the heat treatment at 700°C, the grains of the strip grew slightly, and there was no adhesion between the layers of the strip coils, that is, there was no obvious migration of atoms between the layers of the strip at 700°C. Similarly, the magnetic performance indicators were almost the same, maintaining the iron loss P at 20W / Kg (400Hz1000mT), the coercive force Hc at 115A / m, and the relative magnetic permeability at 3600.

[0142] It can be clearly seen from Examples 5 to 7 that during the heat treatment at 800°C, the grains of the strip material grow significantly. When the lamination coefficient of the strip material coil is 0.9, there is slight adhesion between the layers, that is, when the lamination coefficient is 0.9 at 800°C, there is a small amount of atomic migration between the strip layers; when the lamination coefficient is 0.7 and 0.8, there is no adhesion between the layers; when the lamination coefficient is 0.7, due to the low tension of the strip material coil and the stress release during the heat treatment, the strip material plate shape becomes uneven, affecting the quality of the strip;

[0143] It can be clearly seen from Examples 8 to 15 that during the heat treatment at 900°C, the grains of the strip have grown slightly. Similarly, the magnetic performance indicators are almost the same, maintaining the iron loss P of only 8.6W / Kg (400Hz1000mT), the coercive force Hc of only 45A / m, and the relative magnetic permeability of 10300. When the lamination coefficient of the strip coil is 0.9, there is severe adhesion between the layers, which is most serious when the insulation time is 3 hours, that is, there is a large amount of atomic migration between the strip layers; when the lamination coefficient is 0.8 and the insulation time is 1.5 hours, there is almost no adhesion between the layers, and there is almost no atomic migration between the strip layers; when the lamination coefficient is 0.8 and the insulation time is 2.0 hours, there is a certain amount of adhesion between the layers, and there is a certain amount of atomic migration between the strip layers;

[0144] When the stacking coefficient is 0.8 and the holding time is 3.0 hours, there is serious adhesion between the layers, and there is a lot of atomic migration between the strip layers; when the stacking coefficient is 0.7 and the holding time is 1.5 hours and 2 hours, there is almost no adhesion between the layers, and there is almost no atomic migration between the strip layers; when the stacking coefficient is 0.7 and the holding time is 3 hours, there is a small amount of adhesion between the layers, and there is a small amount of atomic migration between the strip layers;

[0145] When the lamination coefficient is 0.7, the strip material has an uneven shape due to the small coil tension and stress release during the heat treatment process. This phenomenon is more serious than that in Example 3 and seriously affects the quality of the strip.

[0146] Combining Example 1, Example 16, and Example 17, it can be clearly seen that when the heating rate is 10°C / min, the strip shape has a slight unevenness phenomenon. This is because during the heating process, the temperature gradient in the furnace is large, which makes the internal stress release of the strip uneven, resulting in an uneven strip shape. When the heating rate is 20°C / min, the unevenness of the strip shape is more serious than when the heating rate is 10°C / min. This is because the temperature gradient in the furnace is larger, which makes the internal stress release of the strip more uneven, resulting in a more serious unevenness of the strip shape.

[0147] It can be clearly seen from Example 1, Example 18, and Example 19 that when the furnace body is opened for cooling, the magnetic properties decrease relative to cooling with the furnace, the iron loss P reaches 9.2W / Kg (400Hz1000mT), the coercive force Hc reaches 50A / m, and the relative magnetic permeability is only 9500. When the furnace body is opened for cooling with air blowing, the magnetic properties decrease more relative to cooling with the furnace body opened for cooling, the iron loss P reaches 9.6W / Kg (400Hz1000mT), the coercive force Hc reaches 53A / m, and the relative magnetic permeability is only 9000. The reason for this result is that the stress generated inside the strip varies with the cooling speed, and the existence of internal stress affects the reversal of magnetic domains, thereby affecting the magnetic properties of the strip.

[0148] It can be clearly seen from Example 1 and Examples 29 to 30 that when the strip is placed in the air, the strip surface is severely oxidized. When the strip is placed in industrial argon, the strip also oxidizes. This is because the industrial argon is not pure enough and still contains a small amount of oxygen. At high temperature, the oxidation reaction between the iron in the strip and the oxygen in the argon is accelerated. Comparing the results of the strip placed in vacuum and the strip placed in high-purity argon, although the two are equivalent in terms of the performance of the strip, the cost of using high-purity argon is significantly increased, which is contrary to the purpose of the present invention. The purpose of the present invention is not only to ensure the performance of the product, but also to minimize its cost. Therefore, the use of high-purity argon or other protective gases still belongs to the protection scope of the present invention.

[0149] In summary, the embodiment of the present invention adopts the method of providing an ultra-thin strip of high silicon steel made by rapid solidification, and rolling the ultra-thin strip into a strip coil so that there is a certain gap between the strip coil layers; placing the strip coil in a heat treatment furnace at room temperature, and then treating the heat treatment furnace until the pressure of the heat treatment furnace is less than a preset pressure value; heating the heat treatment furnace at a preset heating rate until the temperature in the heat treatment furnace reaches a first preset temperature value and then stopping vacuuming; heat-treating the strip coil in the heat treatment furnace for a preset time, and then cooling the strip coil with the furnace until the temperature in the heat treatment furnace is less than a second preset temperature value to obtain a heat-treated ultra-thin strip, wherein there is no need to first coat a layer of magnesium oxide on the surface of the strip as an isolation layer to prevent adhesion between the strip layers, and to avoid a certain degree of reaction between magnesium oxide and silicon in the strip at high temperature, which affects the performance of the strip. The problem that the heat treatment method of ultra-thin high silicon steel made by rapid solidification in the prior art affects the performance of the strip is solved.

[0150] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A heat treatment method for rapidly solidified high silicon steel ultra-thin strip, characterized in that: The method comprises: Providing a high silicon steel ultra-thin strip made by rapid solidification, and rolling the ultra-thin strip into a strip coil so that there is a certain gap between the strip coil layers; Placing the strip coil in a heat treatment furnace at room temperature, and then treating the heat treatment furnace until the pressure of the heat treatment furnace is less than a preset pressure value; The heat treatment furnace is heated at a preset heating rate until the temperature inside the heat treatment furnace reaches a first preset temperature value and then vacuuming is stopped; The strip coil is subjected to heat preservation treatment in the heat treatment furnace for a preset time, and then the strip coil is cooled with the furnace until the temperature in the heat treatment furnace is less than a second preset temperature value to obtain a heat-treated ultra-thin strip.

2. The heat treatment method for rapidly solidified high silicon steel ultra-thin strip according to claim 1, characterized in that: The lamination coefficient of the strip coil is 0.75-0.

85.

3. The heat treatment method for rapidly solidified high silicon steel ultra-thin strip according to claim 1, characterized in that: The preset pressure value is 100Pa.

4. The heat treatment method for rapidly solidified high silicon steel ultra-thin strip according to claim 1, characterized in that: The preset heating rate is less than 5°C / min.

5. The heat treatment method for rapidly solidified high silicon steel ultra-thin strip according to claim 1, characterized in that: The first preset temperature value is 800°C to 900°C.

6. The heat treatment method for rapidly solidified high silicon steel ultra-thin strip according to claim 1, characterized in that: The heat preservation treatment time is 1.5 hours to 3 hours.

7. The heat treatment method for rapidly solidified high silicon steel ultra-thin strip according to claim 1, characterized in that: The second preset temperature value is 100°C.

8. The heat treatment method for rapidly solidified high silicon steel ultra-thin strip according to claim 1, characterized in that: The steps of placing the strip coil in a heat treatment furnace at room temperature and then treating the heat treatment furnace until the pressure of the heat treatment furnace is less than a preset pressure value include: The strip coil is placed in a heat treatment furnace at room temperature, and then the heat treatment furnace is evacuated or filled with protective gas until the pressure of the heat treatment furnace is less than a preset pressure value.

9. The heat treatment method for rapidly solidified high silicon steel ultra-thin strip according to claim 8, characterized in that: The protective gas is high-purity argon.

10. A rapidly solidified high silicon steel ultra-thin strip, characterized in that: The product is obtained by heat treatment using the heat treatment method for rapidly solidified high silicon steel ultra-thin strip according to any one of claims 1 to 9.

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