Heat treatment method for ultra-thin strip steel of rapidly solidified high silicon steel and ultra-thin strip steel
The heat treatment method for ultra-thin high-silicon steel strips addresses performance issues by controlling furnace conditions and using a protective gas, achieving uniform stress release and restored magnetic properties without a magnesium oxide coating.
Patent Information
- Application Number
- JP2025121432
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-07-22
- Filing Date
- 2025-07-18
- Publication Date
- 2026-02-03
AI Technical Summary
The conventional heat treatment methods for ultra-thin high-silicon steel strips produced by rapid solidification affect the performance of the strips due to the reaction of magnesium oxide with silicon at high temperatures and result in uneven internal stress and magnetic property discrepancies.
A heat treatment method involving winding the ultra-thin strip into a coil with a predetermined gap, treating it in a furnace at controlled pressure and temperature, and using a protective gas like high-purity argon to avoid magnesium oxide coating, ensuring uniform stress release and magnetic property restoration.
The method effectively grows crystal grains, reduces internal stress, and maintains magnetic properties without the need for a magnesium oxide coating, thus enhancing the performance of the ultra-thin high-silicon steel strips.
Smart Images
Figure 2026016339000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to the technical field of steel strip manufacturing, and more particularly to a method for heat treating an extremely thin steel strip made of rapidly solidified high-silicon steel, and to an extremely thin steel strip. [Background technology]
[0002] Ultra-thin high-silicon steel (Fe-6.5 wt.% Si) strip steel (approximately 0.035 mm thick) manufactured by rapid solidification has a cooling rate that is too fast, resulting in the crystal grains becoming too fine and the internal stress becoming too large, ultimately resulting in a certain gap between the magnetic properties and the theoretical values. Therefore, heat treatment is required to grow the crystal grains, reduce the internal stress, and restore the magnetic properties.
[0003] Currently, ultra-thin high-silicon steel strips are generally treated using a heat treatment method similar to that used for conventional silicon steels, in which a layer of magnesium oxide is coated on the surface of the strip before heat treatment as an insulating layer to prevent adhesion between the strip layers, and the remaining magnesium oxide is washed away after heat treatment. This method is not only complicated and expensive, but also has the disadvantage that the magnesium oxide reacts to a certain extent with the silicon in the strip at high temperatures, which affects the performance of the strip. Summary of the Invention [Problem to be solved by the invention]
[0004] Therefore, an object of the present invention is to provide a method for heat treating an extremely thin strip of rapidly solidified high-silicon steel, which aims to solve the problem that the heat treatment method for extremely thin strip of high-silicon steel produced by the conventional rapid solidification method affects the performance of the strip. [Means for solving the problem]
[0005] An embodiment of the present invention is implemented as follows.
[0006] A method for heat treating an ultra-thin strip of rapidly solidified high-silicon steel, the method comprising: providing an ultra-thin strip of high-silicon steel produced by a rapid solidification method, and winding the ultra-thin strip around a coiled steel strip so that a predetermined gap exists between the layers of the coiled steel strip; placing the strip steel coil material in a heat treatment furnace at room temperature and treating the heat treatment furnace until the pressure in the heat treatment furnace is less than a preset pressure value; heating the heat treatment furnace at a preset heating rate, and stopping evacuation after the temperature in the heat treatment furnace reaches a first preset temperature value; and a step of warming the coiled steel strip in the heat treatment furnace for a preset time, and then cooling the coiled steel strip together with the furnace until the temperature in the heat treatment furnace becomes less than a second preset temperature value, thereby obtaining a heat-treated ultra-thin strip steel.
[0007] Furthermore, in the above-mentioned method for heat treating an extremely thin strip of rapidly solidified high-silicon steel, the stacking factor of the strip steel coil material is 0.75 to 0.85.
[0008] Furthermore, in the above-mentioned method for heat treating ultra-thin strip steel of rapidly solidified high-silicon steel, the preset pressure value is 100 Pa.
[0009] Furthermore, in the above-mentioned method for heat treating ultra-thin strip steel of rapidly solidified high-silicon steel, the preset heating rate is less than 5°C / min.
[0010] Furthermore, in the above-mentioned heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel, the first preset temperature value is 800°C to 900°C.
[0011] Furthermore, in the above-mentioned heat treatment method for ultra-thin strip steel of rapidly solidified high-silicon steel, the temperature-retaining treatment time is 1.5 hours to 3 hours.
[0012] Furthermore, in the above-mentioned method for heat treating an extremely thin strip of rapidly solidified high-silicon steel, the second preset temperature value is 100°C.
[0013] Furthermore, in the above-mentioned method for heat treating an extremely thin strip of rapidly solidified high-silicon steel, the step of placing the strip steel coil material in a heat treatment furnace at room temperature and treating the inside of the heat treatment furnace until the pressure inside the heat treatment furnace becomes less than a preset pressure value includes: The method includes placing the strip steel coil material in a heat treatment furnace at room temperature, and treating the material by evacuating the heat treatment furnace or filling the heat treatment furnace with a protective gas until the pressure in the heat treatment furnace becomes less than a preset pressure value.
[0014] Furthermore, in the above-mentioned method for heat treating an extremely thin strip of rapidly solidified high-silicon steel, the protective gas is high-purity argon gas.
[0015] Another object of the present invention is to provide an extremely thin strip of rapidly solidified high-silicon steel obtained by heat treating using the above-mentioned method for heat treating an extremely thin strip of rapidly solidified high-silicon steel. [Effects of the Invention]
[0016] Compared with the prior art, an embodiment of the present invention provides an ultra-thin high-silicon steel strip produced by a rapid solidification method, and heat-treating the steel strip using a method including the steps of: winding the ultra-thin steel strip into a steel strip coil so that a certain gap exists between the layers of the steel strip; placing the steel strip in a heat treatment furnace at room temperature and treating it in the heat treatment furnace until the pressure in the heat treatment furnace is less than a preset pressure value; heating the heat treatment furnace at a preset heating rate and stopping the evacuation after the temperature in the heat treatment furnace reaches a first preset temperature value; holding the steel strip in the heat treatment furnace for a preset time, and then cooling the steel strip together with the furnace until the temperature in the heat treatment furnace is less than a second preset temperature value, thereby obtaining a heat-treated ultra-thin steel strip, wherein there is no need to coat a layer of magnesium oxide on the surface of the steel strip as an insulating layer to prevent adhesion between the steel strip layers, thereby avoiding the magnesium oxide reacting to a certain extent with the silicon in the steel strip at high temperatures and affecting the performance of the steel strip. This solves the problem that the heat treatment method of ultra-thin high-silicon steel produced by the conventional rapid solidification method affects the performance of the strip steel. [Brief explanation of the drawings]
[0017] [Figure 1] 1 is a flow chart of a heat treatment method for a rapidly solidified high-silicon steel strip provided by an embodiment of the present invention. [Figure 2] 1 is a structural diagram of an ultra-thin strip steel produced at a heat treatment temperature of 400°C in a heat treatment method for a rapidly solidified high-silicon steel ultra-thin strip provided by an embodiment of the present invention. [Figure 3] 1 is a structural diagram of an ultra-thin strip steel produced at a heat treatment temperature of 500°C in a heat treatment method for a rapidly solidified high-silicon steel ultra-thin strip provided by an embodiment of the present invention. [Figure 4] 1 is a structural diagram of an ultra-thin strip steel produced at a heat treatment temperature of 600°C in a heat treatment method for a rapidly solidified high-silicon steel ultra-thin strip provided by an embodiment of the present invention. [Figure 5] 1 is a structural diagram of an ultra-thin strip steel produced at a heat treatment temperature of 700°C in a heat treatment method for a rapidly solidified high-silicon steel ultra-thin strip provided by an embodiment of the present invention. [Figure 6] 1 is a structural diagram of an ultra-thin strip steel produced at a heat treatment temperature of 800°C in a heat treatment method for a rapidly solidified high-silicon steel ultra-thin strip provided by an embodiment of the present invention. [Figure 7] 1 is a structural diagram of an ultra-thin strip steel produced at a heat treatment temperature of 900°C in a heat treatment method for a rapidly solidified high-silicon steel ultra-thin strip provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION
[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used in the specification of the present invention herein are for the purpose of describing specific examples only and are not intended to limit the present invention.
[0019] Furthermore, as used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. In the detailed description and claims, a list of items linked with the term "one of" may mean any one of the listed items. For example, if items A and B are listed, the phrase "one of A and B" means A only or B only. In another example, if items A, B, and C are listed, the phrase "one of A, B, and C" means A only, B only, or C only. 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. In the detailed description and claims, a list of items linked with "at least one of," "at least one of," or other similar terminology 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 A only, B only, or A and B. In other instances, 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 A only, or B only, or C only, or A and B (excluding C), or A and C (excluding B), or 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.
[0020] The present invention focuses on the problem that the heat treatment method for ultra-thin high-silicon steel strips produced by the current rapid solidification method affects the performance of the steel strip, and provides a heat treatment method for ultra-thin high-silicon steel strips produced by rapid solidification. Referring to FIG. 1, the method includes: A step S10 of providing an ultra-thin strip of high silicon steel produced by a rapid solidification method, and winding the ultra-thin strip around the coiled steel strip so that a certain gap exists between the layers of the coiled steel strip; Step 11: placing the strip steel coil material in a heat treatment furnace at room temperature and treating the heat treatment furnace until the pressure in the heat treatment furnace is less than a preset pressure value; a step S12 of heating the heat treatment furnace at a preset heating rate, and stopping evacuation after the temperature in the heat treatment furnace reaches a first preset temperature value; and a step S13 of heat-treating the coiled steel strip in the heat treatment furnace for a preset time, and then cooling the coiled steel strip together with the furnace until the temperature in the heat treatment furnace becomes less than a second preset temperature value, thereby obtaining a heat-treated ultra-thin strip steel.
[0021] The steel strip is wound into a coil with a certain gap between the layers, with a stacking factor of 0.75 to 0.85. If the stacking factor is too high, the layers are more likely to stick together; if it is too low, the result is unevenness. Once the heat treatment furnace reaches room temperature, the steel strip coil is placed in the furnace. The furnace is then evacuated or filled with a protective gas such as high-purity argon. If the steel strip is placed in air, the surface of the steel strip is more likely to oxidize. If the pressure inside the furnace is less than 100 Pa, the power is turned on and the heating rate must be less than 5°C / min. If the furnace heating rate is too fast, the internal stress of the steel strip will be unevenly released, resulting in an uneven shape of the steel strip. When the furnace temperature reaches 800-900°C, the evacuation is stopped and the temperature is maintained for 1.5 to 3 hours. Once the holding time is reached, the heating power is turned off and the steel strip coil is cooled along with the furnace. Different cooling rates result in different internal stresses. If internal stress exists, magnetic domain reversal will be affected, affecting the magnetic properties of the steel strip. When the temperature inside the furnace drops below 100°C, air is introduced into the furnace. Once the air pressure inside and outside the furnace is equal, the furnace door is opened and the steel strip coil material is removed from the furnace, completing the heat treatment process.
[0022] On the other hand, the present invention further provides an extremely thin strip of rapidly solidified high-silicon steel obtained by heat treatment using the above-mentioned method for heat treating an extremely thin strip of rapidly solidified high-silicon steel.
[0023] To facilitate understanding of the present invention, several examples of the present invention are set forth below. However, the present invention may be embodied in many different forms and is not limited to the examples set forth herein. Rather, these examples are provided to make the disclosure of the present invention more thorough and complete.
[0024] Example 1 An ultra-thin strip of high-silicon steel produced by a rapid solidification method was provided, and the ultra-thin strip was wound around a coiled steel strip. Since the space factor was 0.8, there were certain gaps between the layers of the coiled steel strip. The steel strip coil material was placed in a heat treatment furnace at room temperature, and the inside of the heat treatment furnace was evacuated until the pressure inside the heat treatment furnace became less than 100 Pa. The heat treatment furnace was heated at a heating rate of 5°C / min, and after the temperature inside the heat treatment furnace reached 1900°C, evacuation was stopped. The coiled steel strip was kept at a constant temperature in the heat treatment furnace for 1.5 hours, and then cooled together with the furnace. When the temperature in the heat treatment furnace became less than 100°C, the heat-treated ultra-thin steel strip was obtained.
[0025] Example 2 This example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.7, the heat treatment temperature is 700°C, and the heat-holding time is 3 hours.
[0026] Example 3 This example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.8, the heat treatment temperature is 700°C, and the heat-holding time is 3 hours.
[0027] Example 4 This example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.9, the heat treatment temperature is 700°C, and the heat-holding time is 3 hours.
[0028] Example 5 This example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.7, the heat treatment temperature is 800°C, and the heat-holding time is 3 hours.
[0029] Example 6 This example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.8, the heat treatment temperature is 700°C, and the heat-holding time is 3 hours.
[0030] Example 7 This example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.9, the heat treatment temperature is 800°C, and the heat-holding time is 3 hours.
[0031] Example 8 This comparative example also provides a heat treatment method for an ultra-thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for an ultra-thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for an ultra-thin strip of rapidly solidified high-silicon steel provided in Example 1 is that the space factor is 0.7 and the heat retention time is 1.5 hours.
[0032] Example 9 This comparative example also provides a heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 is that the space factor is 0.7 and the heat retention time is 2 hours.
[0033] Example 10 This comparative example also provides a heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 is that the space factor is 0.7 and the heat retention time is 3 hours.
[0034] Example 11 This comparative example also provides a heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 is that the space factor is 0.8 and the heat retention time is 2 hours.
[0035] Example 12 This comparative example also provides a heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 is that the space factor is 0.8 and the heat retention time is 3 hours.
[0036] Example 13 This comparative example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 is that the space factor is 0.9 and the heat retention time is 1.5 hours.
[0037] Example 14 This comparative example also provides a heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 is that the space factor is 0.9 and the heat retention time is 2 hours.
[0038] Example 15 This comparative example also provides a heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 is that the space factor is 0.9 and the heat retention time is 3 hours.
[0039] Example 16 This comparative example also provides a heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 is that the heating rate is 10°C / min.
[0040] Example 17 This comparative example also provides a heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 is that the heating rate is 20°C / min.
[0041] Example 18 This comparative example also provides a heat treatment method for an ultra-thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for an ultra-thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for an ultra-thin strip of rapidly solidified high-silicon steel provided in Example 1 is that the cooling method is performed with the cover open.
[0042] Example 19 This comparative example also provides a heat treatment method for an ultra-thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for an ultra-thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for an ultra-thin strip of rapidly solidified high-silicon steel provided in Example 1 is that the cooling method is air-cooling with the cover open.
[0043] Example 20 This comparative example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.7, the heat treatment temperature is 400°C, and the heat-holding time is 3 hours.
[0044] Example 21 This comparative example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.7, the heat treatment temperature is 500°C, and the heat-holding time is 3 hours.
[0045] Example 22 This comparative example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.7, the heat treatment temperature is 600°C, and the heat-holding time is 3 hours.
[0046] Example 23 This comparative example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.8, the heat treatment temperature is 400°C, and the heat-holding time is 3 hours.
[0047] Example 24 This comparative example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.8, the heat treatment temperature is 500°C, and the heat-holding time is 3 hours.
[0048] Example 25 This comparative example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.8, the heat treatment temperature is 600°C, and the heat-holding time is 3 hours.
[0049] Example 26 This comparative example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.9, the heat treatment temperature is 400°C, and the heat-holding time is 3 hours.
[0050] Example 27 This comparative example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.9, the heat treatment temperature is 500°C, and the heat-holding time is 3 hours.
[0051] Example 28 This comparative example also provides a heat treatment method for extremely thin strip of rapidly solidified high-silicon steel. The differences between the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 are that the space factor is 0.9, the heat treatment temperature is 600°C, and the heat-holding time is 3 hours.
[0052] Example 29 This comparative example also provides a heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 is that air is introduced into the heat treatment.
[0053] Example 30 This comparative example also provides a heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 is that high-purity argon gas is introduced during the heat treatment.
[0054] Example 31 This comparative example also provides a heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel. The difference between the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in this comparative example and the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel provided in Example 1 is that industrial argon gas is introduced during the heat treatment.
[0055] Please refer to Table 1 below, which shows the parameters corresponding to the above Examples 1 to 31 of the present invention. It should be noted that the other process parameters of the above Examples are consistent as shown in Table 1 below, in order to ensure the accuracy of the experiment.
[0056] Table 1 JPEG2026016339000002.jpg222170
[0057] 2 to 7, there are shown microstructures of high-silicon steel strips produced at different heat treatment temperatures according to examples of the present invention. Specifically, these are microstructures of high-silicon steel strips produced under conditions of a space factor of 0.8, a holding temperature of 400 to 800°C, a holding time of 3 hours, a heating rate of 5°C / min, a vacuum strip environment, and a cooling method in conjunction with a furnace, and also are microstructures of high-silicon steel strips produced under conditions of a space factor of 0.8, a holding temperature of 900°C, a holding time of 1.5 hours, a heating rate of 5°C / min, a vacuum strip environment, and a cooling method in conjunction with a furnace.
[0058] It is clearly seen that the grain size of the steel strip does not change significantly during the heat treatment under low temperature conditions, and there is no adhesion between the layers of the steel strip coil material, that is, there is no obvious transition of atoms between the steel strip layers at low temperatures. In addition, based on Examples 20 to 28, the iron loss P, coercive force and relative permeability were analyzed, and the magnetic performance indexes were almost the same, with the iron loss P being 23W / Kg (400Hz 1000mT), the coercive force Hc being 124A / m, and the relative permeability only remaining at the level of 3000.
[0059] From Examples 2 to 4, it is clear that during the heat treatment at 700°C, the crystal grains of the steel strip grew slightly, and no adhesion was observed between the layers of the steel strip coil material. In other words, no obvious atomic transition was observed between the steel strip layers at 700°C. Similarly, the magnetic performance indexes were also almost the same, with the iron loss P being 20W / Kg (400Hz 1000mT), the coercive force Hc being 115A / m, and the relative permeability being maintained at the 3600 level.
[0060] From Examples 5 to 7, it is clear that during the heat treatment at 800°C, the crystal grains of the steel strip grow large, and when the space factor of the steel strip coil material is 0.9, slight adhesion is observed between the layers; that is, when the space factor is 0.9 at 800°C, slight atomic transition is observed between the steel strip layers, and when the space factor is 0.7 or 0.8, no adhesion is observed between the layers, and when the space factor is 0.7, the tension of the steel strip coil material is too low and stress is released during the heat treatment, resulting in an uneven shape of the steel strip sheet and affecting the quality of the steel strip.
[0061] It can be clearly seen from Examples 8 to 15 that the crystal grains of the steel strip also grew slightly. Similarly, the magnetic performance indexes were almost the same, with the iron loss P being only 8.6 W / Kg (400 Hz 1000 mT), the coercive force Hc being only 45 A / m, and the relative permeability remaining at a level of 10,300. When the space factor of the steel strip coil material was 0.9, there was significant adhesion between the layers, and the most serious condition was observed when the temperature retention time was 3 hours, i.e., there was a lot of atomic transition between the steel strip layers. When the space factor was 0.8 and the temperature retention time was 1.5 hours, there was almost no adhesion between the layers and almost no atomic transition between the steel strip layers. When the space factor was 0.8 and the temperature retention time was 2.0 hours, there was some adhesion between the layers and some atomic transition between the steel strip layers.
[0062] When the space factor was 0.8 and the heat retention time was 3.0 hours, there was significant adhesion between the layers and more atomic transition between the strip steel layers. When the space factor was 0.7 and the heat retention time was 1.5 hours and 2 hours, there was almost no adhesion between the layers and almost no atomic transition between the strip steel layers. When the space factor was 0.7 and the heat retention time was 3 hours, there was slight adhesion between the layers and slight atomic transition between the strip steel layers.
[0063] When the space factor is 0.7, the tension of the steel strip coil is too small, and the stress is released during the heat treatment process, resulting in an uneven shape of the steel strip. This phenomenon is more serious than in Example 3, and has a serious impact on the quality of the steel strip.
[0064] Based on Examples 1, 16, and 17, it can be clearly seen that when the heating rate is 10°C / min, the shape of the steel strip becomes slightly non-uniform, which is due to the large temperature gradient in the furnace during the heating process, which causes the internal stress of the steel strip to be released non-uniformly, resulting in the shape of the steel strip becoming non-uniform. When the heating rate is 20°C / min, the shape of the steel strip becomes more non-uniform than when the heating rate is 10°C / min, which is due to the larger temperature gradient in the furnace, which causes the internal stress of the steel strip to be released non-uniformly, resulting in the shape of the steel strip becoming non-uniform.
[0065] Based on Examples 1, 18, and 19, it is clear that cooling with the furnace cover open results in a decrease in magnetic properties compared to cooling with the furnace, with iron loss P reaching 9.2 W / Kg (400 Hz 1000 mT), coercive force Hc reaching 50 A / m, and relative permeability being only 9,500. Air-cooling with the furnace cover open results in a greater decrease in magnetic properties than cooling with the furnace cover open, with iron loss P reaching 9.6 W / Kg (400 Hz 1000 mT), coercive force Hc reaching 53 A / m, but relative permeability being only 9,000. The reason for this result is that the cooling rates are different, and the stresses generated inside the steel strip are also different. The presence of internal stress affects the magnetic domain reversal, thereby affecting the magnetic properties of the steel strip.
[0066] It is clear from Examples 1 and 29-30 that when the steel strip was placed in air, the surface of the steel strip was severely oxidized. When the steel strip was placed in industrial argon gas, the steel strip was also oxidized. This is because the purity of industrial argon gas is insufficient and contains trace amounts of oxygen. At high temperatures, the oxidation reaction between the iron in the steel strip and the oxygen in the argon gas is accelerated. Comparing the results of placing the steel strip in a vacuum and placing the steel strip in high-purity argon gas, while both have similar effects on the performance of the steel strip, the cost of using high-purity argon gas is significantly increased, which is contrary to the objective of the present invention, which is to not only ensure product performance but also minimize costs. Therefore, the use of high-purity argon gas and other protective gases is also within the scope of protection of the present invention.
[0067] In summary, an embodiment of the present invention provides an ultra-thin high-silicon steel strip produced by a rapid solidification method, and heat-treating the steel strip using a method including the steps of: winding the ultra-thin steel strip into a steel strip coil so that a certain gap exists between the layers of the steel strip; placing the steel strip in a heat treatment furnace at room temperature and treating it in the heat treatment furnace until the pressure in the heat treatment furnace is less than a preset pressure value; heating the heat treatment furnace at a preset heating rate and stopping the evacuation after the temperature in the heat treatment furnace reaches a first preset temperature value; holding the steel strip in the heat treatment furnace for a preset time, and then cooling the steel strip together with the furnace until the temperature in the heat treatment furnace is less than a second preset temperature value, thereby obtaining a heat-treated ultra-thin steel strip, wherein there is no need to coat a layer of magnesium oxide as an insulating layer on the surface of the steel strip to prevent adhesion between the steel strip layers, and this avoids the magnesium oxide reacting to a certain extent with the silicon in the steel strip at high temperatures and affecting the performance of the steel strip. This solves the problem that the heat treatment method of ultra-thin high-silicon steel produced by the conventional rapid solidification method affects the performance of the strip steel.
[0068] The above examples merely represent some embodiments of the present invention, and although the descriptions are relatively specific and detailed, they should not be understood as limiting the patent scope of the present invention. It should be noted that those skilled in the art can make some modifications and improvements without departing from the concept of the present invention, all of which are within the scope of protection of the present invention. Therefore, the patent scope of the present invention shall be based on the appended claims.
Claims
1. A method for heat treating an ultra-thin strip of rapidly solidified high-silicon steel, comprising: The method comprises: providing an ultra-thin strip of high-silicon steel produced by a rapid solidification method, and winding the ultra-thin strip around a coiled steel strip so that a predetermined gap exists between the layers of the coiled steel strip; placing the strip steel coil material in a heat treatment furnace at room temperature and treating the heat treatment furnace until the pressure in the heat treatment furnace is less than a preset pressure value; heating the heat treatment furnace at a preset heating rate, and stopping evacuation after the temperature in the heat treatment furnace reaches a first preset temperature value; and a step of: warming the coiled steel strip in the heat treatment furnace for a preset time, and then cooling the coiled steel strip together with the furnace, so that when the temperature in the heat treatment furnace becomes less than a second preset temperature value, a heat-treated ultra-thin steel strip is obtained.
2. 2. The method for heat treating an extremely thin strip of rapidly solidified high-silicon steel according to claim 1, wherein the space factor of the strip coil material is 0.75 to 0.
85.
3. 2. The method for heat treating ultra-thin strip steel of rapidly solidified high-silicon steel according to claim 1, wherein the preset pressure value is 100 Pa.
4. 2. The method for heat treating a rapidly solidified high-silicon steel strip as claimed in claim 1, wherein the preset heating rate is less than 5[deg.] C. / min.
5. 2. The method for heat treating a rapidly solidified high-silicon steel strip according to claim 1, wherein the first preset temperature is 800 to 900°C.
6. 2. The method for heat treating ultra-thin strip steel of rapidly solidified high-silicon steel according to claim 1, wherein the heat-retaining treatment time is 1.5 to 3 hours.
7. 2. The method for heat treating a rapidly solidified, ultra-thin strip of high-silicon steel according to claim 1, wherein the second preset temperature is 100°C.
8. The step of placing the strip steel coil material in a heat treatment furnace at room temperature and treating the heat treatment furnace until the pressure in the heat treatment furnace is less than a preset pressure value includes:
2. The method for heat treating ultra-thin strip steel of rapidly solidified high-silicon steel according to claim 1, further comprising placing the strip steel coil material in a heat treatment furnace at room temperature, and treating the material by evacuating the heat treatment furnace to a vacuum or filling the heat treatment furnace with a protective gas until the pressure in the heat treatment furnace becomes less than a preset pressure value.
9. 9. The method for heat treating ultra-thin strip steel of rapidly solidified high-silicon steel according to claim 8, wherein the protective gas is high-purity argon gas.
10. 10. An extremely thin strip of rapidly solidified high-silicon steel, characterized in that the extremely thin strip of rapidly solidified high-silicon steel is obtained by heat treating using the heat treatment method for an extremely thin strip of rapidly solidified high-silicon steel according to any one of claims 1 to 9.