Heat-resistant notched oriented silicon steel three-dimensional wound core and annealing method and device thereof

Abstract

The present invention relates to the field of metal heat treatment technology, and specifically to an annealing method and device for a heat-resistant notched oriented silicon steel three-dimensional wound core. The annealing method for the heat-resistant notched oriented silicon steel three-dimensional wound core provided by the present invention comprises the following operations: (1) placing the three-dimensional wound core to be annealed under high temperature conditions of 860°C to 910°C, and heat treating it for 5 to 15 minutes to obtain a first intermediate product; (2) cooling the first intermediate product to 350°C to 400°C, and keeping it at a constant temperature to obtain a second intermediate product; (3) electromagnetically induction heating the second intermediate product to 480°C to 530°C, and keeping it at a constant temperature to obtain a third intermediate product; (4) cooling the third intermediate product to room temperature to obtain an annealed three-dimensional wound core. The annealing method can effectively reduce the loss value of the three-dimensional wound core without damaging the internal structure of the heat-resistant notched oriented silicon steel three-dimensional wound core, and can also shorten the annealing time and improve the manufacturing efficiency of the three-dimensional wound core finished product.

Description

Technical Field

[0001] The invention relates to the technical field of metal heat treatment, and in particular to a heat-resistant notched oriented silicon steel three-dimensional wound core and an annealing method and device thereof. Background Art

[0002] Compared with traditional flat laminated core transformers, three-dimensional wound core transformers have outstanding advantages such as balanced three-phase magnetic circuit, low no-load loss and load loss, and low operating noise. Using low-loss heat-resistant notched oriented silicon steel to develop ultra-high energy-efficient three-dimensional wound core transformers to significantly improve energy efficiency levels and reduce carbon emissions is one of the important development directions of transformers in the future.

[0003] The magnetic domain refinement effect of traditional low-loss laser-scored oriented silicon steel will disappear at the stress relief annealing temperature of the three-dimensional wound core, so it is not suitable for manufacturing three-dimensional wound core transformers. In recent years, domestic and foreign companies such as China Baosteel, Nippon Steel, and South Korea's Posco have adopted special laser scoring, mechanical scoring, and chemical etching technology routes to develop low-loss heat-resistant scored oriented silicon steel with an iron loss P1.7 / 50 below 0.80W / kg for three-dimensional wound core manufacturing.

[0004] Heat-resistant notched oriented silicon steel will produce obvious internal stress during shearing (curved cutting or stripping) and winding into three-dimensional wound cores. These internal stresses will have a negative impact on the magnetic properties of the three-dimensional wound cores, such as iron loss and magnetic conductivity degradation. In order to eliminate these internal stresses and restore the original magnetic properties of the steel, it is necessary to perform stress relief annealing on the three-dimensional wound cores sheared and wound from heat-resistant notched oriented silicon steel.

[0005] In the production process of three-dimensional wound core, annealing process is one of the core processes, which directly affects the performance of three-dimensional wound core. Reasonable annealing process can effectively reduce the loss value of three-dimensional wound core. If the process is improperly controlled, the loss value of three-dimensional wound core will be high to varying degrees, and even the three-dimensional wound core will be scrapped. However, in the process of realizing the present invention, the inventor found that the annealing method disclosed in the prior art is still not ideal for reducing the loss value of heat-resistant notched oriented silicon steel three-dimensional wound core. Summary of the invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the annealing method in the prior art is not ideal for reducing the loss value of the heat-resistant notched oriented silicon steel three-dimensional rolled core, thereby providing an annealing method and device for a heat-resistant notched oriented silicon steel three-dimensional rolled core that is more effective in reducing the loss value.

[0007] To this end, the present invention provides an annealing method for a heat-resistant notched oriented silicon steel three-dimensional wound core, comprising the following operations:

[0008] (1) placing the three-dimensional wound core to be annealed at a high temperature of 860° C. to 910° C. for heat treatment for 5 to 15 minutes to obtain a first intermediate product;

[0009] (2) cooling the first intermediate product to 350° C. to 400° C. and keeping the product at a constant temperature to obtain a second intermediate product;

[0010] (3) electromagnetic induction heating the second intermediate product to 480° C. to 530° C. and maintaining the temperature to obtain a third intermediate product;

[0011] (4) The third intermediate product is cooled to room temperature to obtain an annealed three-dimensional wound core.

[0012] Optionally, in operation (2), the cooling time is 15 to 20 minutes, and the constant temperature standing time is 30 to 60 minutes.

[0013] Optionally, in operation (3), the electromagnetic induction heating time is 20 to 40 minutes, and the constant temperature insulation time is 120 to 150 minutes.

[0014] Optionally, in operation (4), cooling the third intermediate product to room temperature comprises:

[0015] Cooling the third intermediate product to below 300° C. to obtain a fourth intermediate product, wherein the cooling time is 200 to 300 minutes;

[0016] The fourth intermediate product is naturally cooled in the furnace to below 150° C. to obtain a fifth intermediate product;

[0017] The fifth intermediate product is naturally cooled in air to room temperature to obtain an annealed three-dimensional wound core.

[0018] Optionally, operations (1) to (4) are performed in an inert atmosphere, wherein the inert gas in the inert atmosphere is selected from any one of nitrogen, argon or helium.

[0019] The present invention also provides an annealing device for a heat-resistant notched oriented silicon steel three-dimensional wound core, comprising a heat treatment chamber, a first cooling chamber, an electromagnetic induction heating chamber and a second cooling chamber arranged in sequence, a heating resistance wire is arranged inside the heat treatment chamber, and the heating resistance wire is used to heat the internal environment of the heat treatment chamber; an electromagnetic induction heating coil is arranged inside the electromagnetic induction heating chamber, and the electromagnetic induction heating coil is used to perform electromagnetic induction heating on the three-dimensional wound core located in its inner circle.

[0020] Optionally, a first isolation plate that can be opened and closed is provided between the outlet of the heat treatment chamber and the inlet of the first cooling chamber, a second isolation plate that can be opened and closed is provided between the outlet of the first cooling chamber and the inlet of the electromagnetic induction heating chamber, and a third isolation plate that can be opened and closed is provided between the outlet of the electromagnetic induction heating chamber and the inlet of the second cooling chamber;

[0021] Optionally, the annealing device further comprises a vacuum-pumping and gas-filling preparation chamber, wherein a fourth isolation plate which can be opened and closed is provided between the outlet of the vacuum-pumping and gas-filling preparation chamber and the inlet of the heat treatment chamber; a vacuum-pumping device and a gas-filling device are provided inside the vacuum-pumping and gas-filling preparation chamber, wherein the vacuum-pumping device is used to vacuumize the interior of the annealing device, and the gas-filling device is used to fill the interior of the annealing device with an inert gas;

[0022] Optionally, a fifth isolation plate that can be opened and closed is provided at the entrance of the vacuum and inflation preparation chamber, and a sixth isolation plate that can be opened and closed is provided at the exit of the second cooling chamber.

[0023] Optionally, in the annealing device, the isolation plates at the inlet and outlet of each working chamber can isolate each working chamber separately and form a closed working chamber respectively.

[0024] Optionally, the annealing device further comprises at least one conveying device, which is respectively arranged at the bottom of the vacuum filling preparation chamber, the heat treatment chamber, the first cooling chamber, the electromagnetic induction heating chamber or the second cooling chamber, and each of the conveying devices can rotate independently of each other. Exemplarily, the bottom of the vacuum filling preparation chamber, the heat treatment chamber, the first cooling chamber, the electromagnetic induction heating chamber and the second cooling chamber is respectively provided with a conveying device, and each of the conveying devices is arranged at the same horizontal height. The conveying device can be a conveyor belt or a conveyor shaft.

[0025] Optionally, the heating resistance wire is arranged on the inner wall of the heat treatment chamber. Exemplarily, relative to the direction from the entrance to the exit of the heat treatment chamber, the heating resistance wire is arranged on the upper inner wall, the lower inner wall, the left inner wall and the right inner wall of the heat treatment chamber. The heating resistance wire is used to heat the internal environment of the heat treatment chamber, and can also be used to maintain the temperature of the internal environment of the heat treatment chamber constant. Exemplarily, the heating resistance wire can heat the internal environment of the heat treatment chamber to 860℃~910℃ when powered on, and maintain the internal environment of the heat treatment chamber stable at 860℃~910℃.

[0026] Optionally, the inner ring of the electromagnetic induction heating coil extends in the same direction as the direction from the entrance to the exit of the electromagnetic induction heating chamber, and the inner ring of the electromagnetic induction heating coil is located on the same straight line as the entrance and exit of the electromagnetic induction heating chamber. The inner ring of the electromagnetic induction heating coil can accommodate the passage of the three-dimensional wound core, and perform electromagnetic induction heating on the three-dimensional wound core in its inner ring, and can also be used to maintain a constant temperature of the three-dimensional wound core in the inner ring. Exemplarily, the electromagnetic induction heating coil can evenly heat the three-dimensional wound core in the inner ring to 480°C to 530°C when powered on, and maintain the overall temperature of the three-dimensional wound core in the inner ring stable at 480°C to 530°C.

[0027] Optionally, a fan is provided inside the first cooling chamber, and a water cooling jacket is provided outside the first cooling chamber, and the water cooling jacket is covered on the outer wall of the first cooling chamber. The fan is used to circulate the air inside the first cooling chamber and transfer the heat to the external water cooling jacket, so as to achieve the purpose of rapid cooling, and the circulation speed of the air inside the first cooling chamber is controlled by controlling the fan speed, so as to control the cooling speed of the three-dimensional wound core inside the first cooling chamber.

[0028] Optionally, a fan is provided inside the second cooling chamber, and at least one gas circulation pipe is provided outside, and the two ends of each gas circulation pipe are connected to the top and bottom of the second cooling chamber respectively. The fan is used to circulate the air inside the second cooling chamber in the second cooling chamber and the gas circulation pipe, and the high-temperature gas enters the gas circulation pipe and is cooled, and then flows into the second cooling chamber. When the fan is started, the second cooling chamber is used to quickly cool the three-dimensional wound core, and the circulation speed of the air is controlled by controlling the fan speed, thereby controlling the cooling speed of the three-dimensional wound core inside the second cooling chamber; when the fan is turned off, the second cooling chamber is used to naturally cool the three-dimensional wound core along with the furnace.

[0029] The present invention also provides a heat-resistant notched oriented silicon steel three-dimensional wound core, which is obtained by annealing by any of the above-mentioned annealing methods for a heat-resistant notched oriented silicon steel three-dimensional wound core.

[0030] The present invention also provides a three-dimensional wound core transformer, comprising at least one of the above-mentioned heat-resistant notched oriented silicon steel three-dimensional wound cores.

[0031] The technical solution of the present invention has the following advantages:

[0032] 1. The heat-resistant notched oriented silicon steel three-dimensional coil core annealing method provided by the present invention is to first directly place the three-dimensional coil core to be annealed under high temperature conditions of 860℃~910℃ for heat treatment for 5~15min. The high temperature heat treatment process can drive the microstructure of the burrs on the surface of the three-dimensional coil core to recover or recrystallize quickly, thereby effectively eliminating the burr stress on the surface of the three-dimensional coil core. At the same time, the short heat treatment time can ensure that the internal structure of the three-dimensional coil core is at a lower temperature during the heat treatment process, avoiding the microstructure of the internal notched area from changing due to high temperature during the heat treatment process and affecting the magnetic properties; in addition, after cooling, the constant temperature is allowed to stand still, which can ensure that the inside and outside of the three-dimensional coil core are at the same temperature. After the standing still, electromagnetic induction heating is used to ensure that the inside and outside of the three-dimensional coil core are uniformly heated at the same time, so that all parts of the three-dimensional coil core are at the annealing temperature at the same time, thereby fully eliminating the internal winding stress of the three-dimensional coil core (the high-density dislocations in the winding deformation zone disappear in the form of recovery). Therefore, the annealing method of the present invention can effectively reduce the loss value of the three-dimensional coil core without damaging the internal structure of the three-dimensional coil core.

[0033] 2. The three-dimensional wound core annealing method provided by the present invention has an annealing cycle of 18-20 hours, which significantly shortens the annealing cycle. It not only improves the processing efficiency of the three-dimensional wound core, but also reduces the power loss during the annealing process, effectively reduces the manufacturing cost, and lays a foundation for the large-scale promotion and application of the three-dimensional wound core.

[0034] 3. The three-dimensional wound core annealing device provided by the present invention has various working chambers that can work in coordination and continuously, and can realize a refined and continuous three-dimensional wound core annealing process, laying a foundation for mass production of three-dimensional wound cores. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 A schematic diagram of an annealing device for a three-dimensional wound core according to the present invention is exemplarily shown;

[0037] Figure 2 The process curve diagram of the annealing method of the three-dimensional wound core of the present invention is exemplified.

[0038] Reference numerals:

[0039] 1- Heat treatment chamber 2- First cooling chamber

[0040] 3-Electromagnetic induction heating chamber 4-Second cooling chamber

[0041] 5-Vacuuming and filling the preparation chamber 6-First isolation plate

[0042] 7- Second isolation board 8- Third isolation board

[0043] 9-Fourth isolation board 10-Fifth isolation board

[0044] 11-sixth isolation plate 12-heating resistance wire

[0045] 13-Electromagnetic induction heating coil 14-Fan

[0046] 15-Transmission device DETAILED DESCRIPTION

[0047] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0048] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0049] Figure 1 A schematic diagram of an annealing device for a heat-resistant notched oriented silicon steel three-dimensional wound core according to the present invention is shown as an example. Figure 1 As shown, the annealing device may include a heat treatment chamber 1, a first cooling chamber 2, an electromagnetic induction heating chamber 3, a second cooling chamber 4 and a vacuum and gas filling preparation chamber 5, a first isolation plate 6 that can be opened and closed is provided between the outlet of the heat treatment chamber 1 and the inlet of the first cooling chamber 2, a second isolation plate 7 that can be opened and closed is provided between the outlet of the first cooling chamber 2 and the inlet of the electromagnetic induction heating chamber 3, a third isolation plate 8 that can be opened and closed is provided between the outlet of the electromagnetic induction heating chamber 3 and the inlet of the second cooling chamber 4, a fourth isolation plate 9 that can be opened and closed is provided between the outlet of the vacuum and gas filling preparation chamber 5 and the inlet of the heat treatment chamber 1, a fifth isolation plate 10 that can be opened and closed is provided at the inlet of the vacuum and gas filling preparation chamber 5, and a sixth isolation plate 11 that can be opened and closed is provided at the outlet of the second cooling chamber 4.

[0050] A heating resistor wire 12 is arranged on the inner wall of the heat treatment chamber 1, an electromagnetic induction heating coil 13 is arranged inside the electromagnetic induction heating chamber 3, a vacuuming device and an air-filling device are arranged inside the vacuuming and air-filling preparation chamber 5, a fan 14 is arranged inside the first cooling chamber 2, and a water-cooling jacket is arranged outside, and a fan 14 is arranged inside the second cooling chamber 4, and a gas circulation pipeline is arranged outside. A conveying device 15 is respectively arranged at the bottom of the vacuuming and air-filling preparation chamber 5, the heat treatment chamber 1, the first cooling chamber 2, the electromagnetic induction heating chamber 3, and the second cooling chamber 4.

[0051] Figure 1 The annealing apparatus shown works as follows:

[0052] Before annealing the three-dimensional rolled core, evacuate the interior of the annealing device to a vacuum degree lower than 13Pa, fill it with an inert gas with a purity higher than 99.99%, and close all isolation plates; use the heating resistor 12 to raise the internal ambient temperature of the heat treatment chamber 1 to 860°C~910°C and maintain a constant temperature; open the fifth isolation plate 10, transfer the three-dimensional rolled core on the transport trolley to the vacuum and gas filling preparation chamber 5, and close the fifth isolation plate 10; evacuate the interior of the vacuum and gas filling preparation chamber 5 to a vacuum degree lower than 13Pa, and fill it with an inert gas with a purity higher than 99.99%; open the fourth isolation plate 9, transfer the three-dimensional rolled core to the heat treatment chamber 1, close the fourth isolation plate 9, and heat treat for 5~15 minutes; open the first isolation plate 6, transfer the three-dimensional rolled core to the first cooling chamber 2, close the first isolation plate 6, start the fan 14, and wait for the three-dimensional rolled core to be heated. After the surface temperature of the wound core drops to 350°C~400°C, turn off the fan 14 and let it stand at a constant temperature; after standing, open the second isolation plate 7, transfer the three-dimensional wound core to the inner circle of the electromagnetic induction heating coil 13 in the electromagnetic induction heating chamber 3, close the second isolation plate 7, and use the electromagnetic induction heating coil 13 to evenly heat the three-dimensional wound core to 480°C~530°C, and then keep it at a constant temperature of 480°C~530°C; after the insulation is completed, open the third isolation plate 8, transfer the three-dimensional wound core to the second cooling chamber 4, close the third isolation plate 8, turn on the fan 14, cool the three-dimensional wound core to below 300°C, turn off the fan 14, and allow the three-dimensional wound core to naturally cool to below 150°C with the furnace; open the sixth isolation plate 11, transfer the three-dimensional wound core to the outside of the annealing device, and naturally air-cool it to room temperature in the air to obtain the annealed three-dimensional wound core.

[0053] The heat-resistant notch-oriented silicon steel three-dimensional wound core involved in the embodiments and comparative examples of the present invention is processed and provided by Haihong Electric Co., Ltd., with a model of 10kV / 400kVA. The heat-resistant notch-oriented silicon steel used is produced and provided by Baosteel Co., Ltd., with a model of B23HS080.

[0054] Example 1

[0055] use Figure 1The annealing device shown in the figure performs annealing treatment on the heat-resistant notched oriented silicon steel three-dimensional wound core according to the following operations:

[0056] (1) The interior of the annealing device is evacuated to a vacuum degree of less than 13 Pa, filled with nitrogen with a purity of more than 99.99%, all isolation plates are closed, and then the ambient temperature inside the heat treatment chamber is raised to 870° C. and maintained at a constant temperature;

[0057] (2) Using a transport trolley, transport the three three-dimensional coiled cores to be annealed to the front of the fifth isolation plate, open the fifth isolation plate, transfer the three three-dimensional coiled cores to be annealed to the vacuum filling preparation chamber, close the fifth isolation plate, evacuate the inside of the vacuum filling preparation chamber to a vacuum degree lower than 13 Pa, and fill it with nitrogen with a purity higher than 99.99%;

[0058] (3) opening the fourth isolation plate, transferring the three three-dimensional wound cores to be annealed to the heat treatment chamber, closing the fourth isolation plate, and subjecting the three-dimensional wound cores to be annealed to heat treatment at a high temperature of 870° C. for 15 min to obtain a first intermediate product;

[0059] (4) After the heat treatment is completed, the first isolation plate is opened, the first intermediate product is transferred to the first cooling chamber, the first isolation plate is closed, the fan is started, and the fan speed is controlled so that the surface temperature of the first intermediate product drops to 360° C. within 15 minutes, the fan is turned off, and the product is kept at a constant temperature of 360° C. for 35 minutes to obtain a second intermediate product;

[0060] (5) After the standing period is completed, the second isolation plate is opened, and the second intermediate product is transferred to the inner circle of the electromagnetic induction heating coil in the electromagnetic induction heating chamber. The second isolation plate is closed, and the power of the electromagnetic induction heating coil is controlled so that the temperature of the second intermediate product is evenly increased to 490° C. within 25 minutes, and the temperature is kept constant at 490° C. for 150 minutes to obtain a third intermediate product;

[0061] (6) After the heat preservation is completed, the third isolation plate is opened, the third intermediate product is transferred to the second cooling chamber, the third isolation plate is closed, the fan is turned on, and the fan speed is controlled so that the temperature of the third intermediate product is cooled to less than 300° C. within 240 minutes, and the fan is turned off to obtain the fourth intermediate product;

[0062] (7) allowing the fourth intermediate product to be naturally cooled in the second cooling chamber to a temperature below 150° C., thereby obtaining a fifth intermediate product;

[0063] (8) Open the sixth isolation plate, transfer the fifth intermediate product to the outside of the second cooling chamber, and naturally cool it to room temperature in the air to obtain an annealed three-dimensional wound core.

[0064] Example 2

[0065] use Figure 1The annealing device shown in the figure performs annealing treatment on the heat-resistant notched oriented silicon steel three-dimensional wound core according to the following operations:

[0066] (1) The interior of the annealing device is evacuated to a vacuum degree of less than 13 Pa, filled with nitrogen with a purity of more than 99.99%, all isolation plates are closed, and then the ambient temperature inside the heat treatment chamber is raised to 890° C. and maintained at a constant temperature;

[0067] (2) Using a transport trolley, transport the three three-dimensional coiled cores to be annealed to the front of the fifth isolation plate, open the fifth isolation plate, transfer the three three-dimensional coiled cores to be annealed to the vacuum filling preparation chamber, close the fifth isolation plate, evacuate the inside of the vacuum filling preparation chamber to a vacuum degree lower than 13 Pa, and fill it with nitrogen with a purity higher than 99.99%;

[0068] (3) opening the fourth isolation plate, transferring the three three-dimensional wound cores to be annealed to the heat treatment chamber, closing the fourth isolation plate, and subjecting the three-dimensional wound cores to annealing to heat treatment at a high temperature of 890° C. for 12 minutes to obtain a first intermediate product;

[0069] (4) After the heat treatment is completed, the first isolation plate is opened, the first intermediate product is transferred to the first cooling chamber, the first isolation plate is closed, the fan is started, and the fan speed is controlled so that the surface temperature of the first intermediate product drops to 370° C. within 20 minutes, the fan is turned off, and the product is kept at a constant temperature of 370° C. for 45 minutes to obtain a second intermediate product;

[0070] (5) After the standing period is completed, the second isolation plate is opened, and the second intermediate product is transferred to the inner circle of the electromagnetic induction heating coil in the electromagnetic induction heating chamber. The second isolation plate is closed, and the power of the electromagnetic induction heating coil is controlled so that the temperature of the second intermediate product is evenly increased to 510° C. within 30 minutes, and the temperature is kept constant at 510° C. for 130 minutes to obtain a third intermediate product;

[0071] (6) After the heat preservation is completed, the third isolation plate is opened, the third intermediate product is transferred to the second cooling chamber, the third isolation plate is closed, the fan is turned on, and the fan speed is controlled so that the temperature of the third intermediate product is cooled to less than 300° C. within 270 min, and the fan is turned off to obtain the fourth intermediate product;

[0072] (7) allowing the fourth intermediate product to be naturally cooled in the second cooling chamber to a temperature below 150° C., thereby obtaining a fifth intermediate product;

[0073] (8) Open the sixth isolation plate, transfer the fifth intermediate product to the outside of the second cooling chamber, and naturally cool it to room temperature in the air to obtain an annealed three-dimensional wound core.

[0074] Example 3

[0075] use Figure 1The annealing device shown in the figure performs annealing treatment on the heat-resistant notched oriented silicon steel three-dimensional wound core according to the following operations:

[0076] (1) The interior of the annealing device is evacuated to a vacuum degree of less than 13 Pa, filled with nitrogen with a purity of more than 99.99%, all isolation plates are closed, and then the ambient temperature inside the heat treatment chamber is raised to 910° C. and maintained at a constant temperature;

[0077] (2) Using a transport trolley, transport the three three-dimensional coiled cores to be annealed to the front of the fifth isolation plate, open the fifth isolation plate, transfer the three three-dimensional coiled cores to be annealed to the vacuum filling preparation chamber, close the fifth isolation plate, evacuate the inside of the vacuum filling preparation chamber to a vacuum degree lower than 13 Pa, and fill it with nitrogen with a purity higher than 99.99%;

[0078] (3) opening the fourth isolation plate, transferring the three three-dimensional wound cores to be annealed to the heat treatment chamber, closing the fourth isolation plate, and subjecting the three-dimensional wound cores to be annealed to heat treatment at a high temperature of 910° C. for 7 min to obtain a first intermediate product;

[0079] (4) After the heat treatment is completed, the first isolation plate is opened, the first intermediate product is transferred to the first cooling chamber, the first isolation plate is closed, the fan is started, and the fan speed is controlled so that the surface temperature of the first intermediate product drops to 400° C. within 20 minutes, the fan is turned off, and the product is kept at a constant temperature of 400° C. for 50 minutes to obtain a second intermediate product;

[0080] (5) After the standing period is completed, the second isolation plate is opened, and the second intermediate product is transferred to the inner circle of the electromagnetic induction heating coil in the electromagnetic induction heating chamber. The second isolation plate is closed, and the power of the electromagnetic induction heating coil is controlled so that the temperature of the second intermediate product is evenly increased to 530° C. within 40 minutes, and the temperature is kept constant at 530° C. for 120 minutes to obtain a third intermediate product;

[0081] (6) After the insulation is completed, the third isolation plate is opened, the third intermediate product is transferred to the second cooling chamber, the third isolation plate is closed, the fan is turned on, and the fan speed is controlled so that the temperature of the third intermediate product is cooled to less than 300° C. within 300 min, and the fan is turned off to obtain a fourth intermediate product;

[0082] (7) allowing the fourth intermediate product to be naturally cooled in the second cooling chamber to a temperature below 150° C., thereby obtaining a fifth intermediate product;

[0083] (8) Open the sixth isolation plate, transfer the fifth intermediate product to the outside of the second cooling chamber, and naturally cool it to room temperature in the air to obtain an annealed three-dimensional wound core.

[0084] Example 4

[0085] use Figure 1The annealing device shown in the figure performs annealing treatment on the heat-resistant notched oriented silicon steel three-dimensional wound core according to the following operations:

[0086] (1) The interior of the annealing device is evacuated to a vacuum degree of less than 13 Pa, filled with nitrogen with a purity of more than 99.99%, all isolation plates are closed, and then the ambient temperature inside the heat treatment chamber is raised to 860° C. and maintained at a constant temperature;

[0087] (2) Using a transport trolley, transport the three three-dimensional coiled cores to be annealed to the front of the fifth isolation plate, open the fifth isolation plate, transfer the three three-dimensional coiled cores to be annealed to the vacuum filling preparation chamber, close the fifth isolation plate, evacuate the inside of the vacuum filling preparation chamber to a vacuum degree lower than 13 Pa, and fill it with nitrogen with a purity higher than 99.99%;

[0088] (3) opening the fourth isolation plate, transferring the three three-dimensional wound cores to be annealed to the heat treatment chamber, closing the fourth isolation plate, and subjecting the three-dimensional wound cores to be annealed to heat treatment at a high temperature of 860° C. for 5 minutes to obtain a first intermediate product;

[0089] (4) After the heat treatment is completed, the first isolation plate is opened, the first intermediate product is transferred to the first cooling chamber, the first isolation plate is closed, the fan is started, and the fan speed is controlled so that the surface temperature of the first intermediate product drops to 350° C. within 15 minutes, the fan is turned off, and the product is kept at a constant temperature of 350° C. for 60 minutes to obtain a second intermediate product;

[0090] (5) After the standing period is completed, the second isolation plate is opened, and the second intermediate product is transferred to the inner circle of the electromagnetic induction heating coil in the electromagnetic induction heating chamber. The second isolation plate is closed, and the power of the electromagnetic induction heating coil is controlled so that the temperature of the second intermediate product is evenly increased to 480° C. within 20 minutes, and the temperature is kept constant at 480° C. for 140 minutes to obtain a third intermediate product;

[0091] (6) After the heat preservation is completed, the third isolation plate is opened, the third intermediate product is transferred to the second cooling chamber, the third isolation plate is closed, the fan is turned on, and the fan speed is controlled so that the temperature of the third intermediate product is cooled to less than 300° C. within 200 min, and the fan is turned off to obtain the fourth intermediate product;

[0092] (7) allowing the fourth intermediate product to be naturally cooled in the second cooling chamber to a temperature below 150° C., thereby obtaining a fifth intermediate product;

[0093] (8) Open the sixth isolation plate, transfer the fifth intermediate product to the outside of the second cooling chamber, and naturally cool it to room temperature in the air to obtain an annealed three-dimensional wound core.

[0094] Comparative Example 1

[0095] The heat-resistant notched oriented silicon steel three-dimensional wound core was annealed according to the method of Example 1, except that the ambient temperature inside the heat treatment chamber of this comparative example was kept constant at 820°C, and the heat treatment temperature in operation (3) was 820°C.

[0096] Comparative Example 2

[0097] The heat-resistant notched oriented silicon steel three-dimensional wound core was annealed according to the method of Example 1, except that the ambient temperature inside the heat treatment chamber of this comparative example was kept constant at 920°C, the heat treatment temperature in operation (3) was 920°C, and the heat treatment time was 10 minutes.

[0098] Comparative Example 3

[0099] use Figure 1 The annealing device shown in the figure performs annealing treatment on the heat-resistant notched oriented silicon steel three-dimensional wound core according to the following operations:

[0100] (1) Evacuate the interior of the annealing device to a vacuum degree lower than 13 Pa, fill it with nitrogen with a purity higher than 99.99%, and close all isolation plates;

[0101] (2) Using a transport trolley, transport the three three-dimensional coiled cores to be annealed to the front of the fifth isolation plate, open the fifth isolation plate, transfer the three three-dimensional coiled cores to be annealed to the vacuum filling preparation chamber, close the fifth isolation plate, evacuate the inside of the vacuum filling preparation chamber to a vacuum degree lower than 13 Pa, and fill it with nitrogen with a purity higher than 99.99%;

[0102] (3) opening the fourth isolation plate, transferring the three three-dimensional coiled cores to be annealed to the heat treatment chamber, closing the fourth isolation plate, raising the internal ambient temperature of the heat treatment chamber to 870° C. within 120 min using a heating resistance wire, and heat treating at a high temperature of 870° C. for 15 min to obtain a first intermediate product;

[0103] (4) After the heat treatment is completed, the first isolation plate is opened, the first intermediate product is transferred to the first cooling chamber, the first isolation plate is closed, the fan is started, and the fan speed is controlled so that the surface temperature of the first intermediate product drops to 360° C. within 15 minutes, the fan is turned off, and the product is kept at a constant temperature of 360° C. for 35 minutes to obtain a second intermediate product;

[0104] (5) After the standing period is completed, the second isolation plate is opened, and the second intermediate product is transferred to the inner circle of the electromagnetic induction heating coil in the electromagnetic induction heating chamber. The second isolation plate is closed, and the power of the electromagnetic induction heating coil is controlled so that the temperature of the second intermediate product is evenly increased to 490° C. within 25 minutes, and the temperature is kept constant at 490° C. for 150 minutes to obtain a third intermediate product;

[0105] (6) After the heat preservation is completed, the third isolation plate is opened, the third intermediate product is transferred to the second cooling chamber, the third isolation plate is closed, the fan is turned on, and the fan speed is controlled so that the temperature of the third intermediate product is cooled to less than 300° C. within 240 minutes, and the fan is turned off to obtain the fourth intermediate product;

[0106] (7) allowing the fourth intermediate product to be naturally cooled in the second cooling chamber to a temperature below 150° C., thereby obtaining a fifth intermediate product;

[0107] (8) Open the sixth isolation plate, transfer the fifth intermediate product to the outside of the second cooling chamber, and naturally cool it to room temperature in the air to obtain an annealed three-dimensional wound core.

[0108] Experimental example

[0109] For each heat-resistant notched oriented silicon steel three-dimensional wound core involved in Examples 1-4 and Comparative Examples 1-3, the loss value of each three-dimensional wound core was measured before and after annealing, and the measuring method was as follows:

[0110] The power analyzer (precision power analyzer (WT3000-YOKOGAWA)) is used to measure the current of the primary excitation winding of the three-dimensional wound core, which corresponds to the magnetic field strength inside the three-dimensional wound core; the power analyzer is used to measure the voltage of the secondary induction winding of the three-dimensional wound core, which corresponds to the magnetic polarization strength inside the three-dimensional wound core. The loss value of the three-dimensional wound core corresponds to the area enclosed by the hysteresis loop composed of the magnetic field strength H(t) and the magnetic polarization strength J(t). The loss value P s Calculate according to formula (1):

[0111]

[0112] Where: P s is the core loss value of the three-dimensional coil, ρ m is the material density of the three-dimensional wound core, f is the magnetizing frequency, T is the magnetizing period, N2 is the number of turns of the secondary coil, A is the cross-sectional area of ​​the three-dimensional wound core, U2(t) is the secondary induced voltage, and H(t) is the magnetic field strength.

[0113] The measurement results are shown in Table 1.

[0114] Table 1 Loss measurement results of each three-dimensional wound core before and after annealing in the embodiment and the comparative example

[0115]

[0116] It can be seen from Table 1 that the loss of each three-dimensional coiled core in Examples 1-4 is significantly reduced. Compared with before annealing, the loss reduction ratio ranges from 30.0% to 35.3%; the annealing cycle is 18 to 20 hours, which significantly shortens the heat treatment cycle and improves the processing efficiency of the coiled core, while the cycle of the traditional heat treatment method is 30 to 40 hours. In Comparative Example 1, the core loss reduction ratio is relatively low. The reason is that during the annealing process to eliminate the burr stress at the edge of the coiled core, the temperature is too low and the time is too short, which is not enough to drive the microstructure of the deformation burr area to recrystallize or recover quickly, resulting in an insignificant loss reduction effect at the edge of the core. In Comparative Example 2, the core loss reduction ratio is also relatively low. The reason is that during the annealing process to eliminate the burr stress at the edge of the core, due to the high temperature, the structure of the heat-resistant notched steel strip inside the coiled core changes to varying degrees, the magnetic domain width of the notch line micro-area increases, and the magnetic domain refinement loss reduction effect is weakened.

[0117] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for annealing a heat-resistant notched oriented silicon steel three-dimensional wound core, characterized in that: The following operations are included: (1) placing the three-dimensional wound core to be annealed at a high temperature of 860° C. to 910° C. for heat treatment for 5 to 15 minutes to obtain a first intermediate product; (2) cooling the first intermediate product to 350° C. to 400° C. and keeping the product at a constant temperature to obtain a second intermediate product; (3) electromagnetically induction heating the second intermediate product to 480° C. to 530° C. and maintaining the temperature to obtain a third intermediate product; (4) The third intermediate product is cooled to room temperature to obtain an annealed three-dimensional wound core.

2. The annealing method according to claim 1, characterized in that: In operation (2), the cooling time is 15 to 20 minutes, and the constant temperature standing time is 30 to 60 minutes.

3. The annealing method according to claim 1, characterized in that: In operation (3), the electromagnetic induction heating time is 20 to 40 minutes, and the constant temperature insulation time is 120 to 150 minutes.

4. The annealing method according to any one of claims 1 to 3, characterized in that: In operation (4), cooling the third intermediate product to room temperature comprises: Cooling the third intermediate product to below 300° C. to obtain a fourth intermediate product, wherein the cooling time is 200 to 300 minutes; The fourth intermediate product is naturally cooled in the furnace to below 150° C. to obtain a fifth intermediate product; The fifth intermediate product is naturally cooled in air to room temperature to obtain an annealed three-dimensional wound core.

5. The annealing method according to any one of claims 1 to 3, characterized in that: Operations (1) to (4) are carried out in an inert atmosphere, wherein the inert gas in the inert atmosphere is selected from any one of nitrogen, argon or helium.

6. The annealing method according to claim 1, characterized in that: The annealing device used in the annealing method includes a heat treatment chamber, a first cooling chamber, an electromagnetic induction heating chamber and a second cooling chamber arranged in sequence. A heating resistance wire is arranged inside the heat treatment chamber, and the heating resistance wire is used to heat the internal environment of the heat treatment chamber; an electromagnetic induction heating coil is arranged inside the electromagnetic induction heating chamber, and the electromagnetic induction heating coil is used to perform electromagnetic induction heating on the three-dimensional wound iron core located in its inner circle.

7. The annealing method according to claim 6, characterized in that: A first isolation plate that can be opened and closed is provided between the outlet of the heat treatment chamber and the inlet of the first cooling chamber, a second isolation plate that can be opened and closed is provided between the outlet of the first cooling chamber and the inlet of the electromagnetic induction heating chamber, and a third isolation plate that can be opened and closed is provided between the outlet of the electromagnetic induction heating chamber and the inlet of the second cooling chamber; And / or, the annealing device further comprises a vacuum-pumping and gas-filling preparation chamber, a fourth isolation plate which can be opened and closed is provided between the outlet of the vacuum-pumping and gas-filling preparation chamber and the inlet of the heat treatment chamber; a vacuum-pumping device and a gas-filling device are provided inside the vacuum-pumping and gas-filling preparation chamber, the vacuum-pumping device is used to evacuate the inside of the annealing device, and the gas-filling device is used to fill the inside of the annealing device with an inert gas; And / or, a fifth isolation plate that can be opened and closed is provided at the entrance of the vacuum and inflation preparation chamber, and a sixth isolation plate that can be opened and closed is provided at the exit of the second cooling chamber.

8. The annealing method according to claim 7, characterized in that: The annealing device further comprises at least one conveying device, which is respectively arranged at the bottom of the vacuum filling preparation chamber, the heat treatment chamber, the first cooling chamber, the electromagnetic induction heating chamber and the second cooling chamber, and each of the conveying devices can rotate independently of each other; And / or, a fan is provided inside the first cooling chamber, and a water cooling jacket is provided outside the first cooling chamber, and the water cooling jacket is covered on the outer wall of the first cooling chamber; And / or, a fan is provided inside the second cooling chamber, and at least one gas circulation pipe is provided outside the second cooling chamber, and both ends of each of the gas circulation pipes are respectively connected to the top and the bottom of the second cooling chamber.

9. A heat-resistant notched oriented silicon steel three-dimensional wound core, characterized in that: The invention is obtained by annealing the heat-resistant notched oriented silicon steel three-dimensional wound core according to any one of claims 1 to 5.

10. A three-dimensional wound core transformer, characterized in that: The invention comprises at least one heat-resistant notched oriented silicon steel three-dimensional wound core as claimed in claim 9.

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