Heat treatment method for residual magnetism of iron-based nanocrystalline magnetic core

Abstract

The invention discloses a heat treatment method for residual magnetism of an iron-based nanocrystalline magnetic core, which comprises the following steps: S1, building a three-furnace transfer atmosphere annealing furnace mechanism and 2-3 four-furnace transfer composite magnetic field annealing furnace mechanisms, S2, firstly carrying out surface treatment on an iron-based nanocrystalline strip, then winding the strip into a magnetic core by using a constant tension winding machine, and S4, carrying out heat treatment on the magnetic core, carrying out heating treatment in a three-furnace transfer atmosphere annealing furnace mechanism, and then carrying out annealing treatment; and the heat treatment box annealed by the annealing furnace 3 in the step S2 is conveyed to a four-furnace transfer composite magnetic field annealing furnace mechanism for magnetic field heating annealing so as to eliminate residual magnetism. The problem of serious heat loss caused by large temperature change in each furnace body is solved, continuous reaction is achieved, and the heat treatment efficiency is higher.

Description

Technical Field

[0001] The invention relates to the technical field of heat treatment of residual magnetism of an iron-based nanocrystalline magnetic core, and in particular to a heat treatment method of residual magnetism of an iron-based nanocrystalline magnetic core. Background Art

[0002] Soft magnetic materials have magnetic properties such as low coercivity and high magnetic permeability. They are the raw materials for making magnetic cores of inductors, chokes, sensors, etc. They have been widely used in the power, motor and electronics industries. As an emerging material in this field, nanocrystalline alloy soft magnetic materials have the advantages of high saturation magnetic induction intensity, high magnetic permeability, low loss, high resistivity and high toughness, which have attracted the attention of many scientific researchers. They have been put into production and application since the early stage of research. In addition, their preparation process is simple, energy-saving and environmentally friendly. In a few fields, they have partially replaced traditional silicon steel and ferrite materials. With the maturity of technological development, nanocrystalline magnetic cores are increasingly widely used in inverter power supplies. However, in order to reduce the remanence of this magnetic core, the existing annealing process level can only be ≤10mT even through constant tension annealing, which affects the stable and reliable operation of the power system and accurate metering and measurement. Moreover, the entire reaction is carried out in two furnaces, and multiple heating and annealing cooling are required, and the time is relatively short, resulting in the furnace body. A lot of heat is consumed. Since the furnace body heats up and cools down quickly, the iron-based nanocrystalline magnetic cores accumulated in the furnace will have errors in cooling and heating up due to the uneven temperature in the furnace. The heat treatment effect on the residual magnetism will be different. For example, if the size of the furnace body is changed or the number of heated iron-based nanocrystalline magnetic cores is reduced, the generation efficiency will be low. Therefore, a continuous reaction furnace body structure is needed first. Under the condition of small furnace body temperature conversion, continuous heat treatment of residual magnetism is carried out to achieve efficient treatment, smaller error in treatment conditions of each iron-based nanocrystalline magnetic core, and lower energy loss. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, one purpose of the present invention is to provide a heat treatment method for the remanence of an iron-based nanocrystalline magnetic core, which solves the problems of large energy loss in the heat treatment of the remanence of an iron-based nanocrystalline magnetic core, errors in the heat treatment conditions of the remanence of different iron-based nanocrystalline magnetic cores when the treatment amount is large, and different treatment effects.

[0004] A heat treatment method for residual magnetism of an iron-based nanocrystalline magnetic core proposed in the present invention is characterized in that: the specific method is as follows:

[0005] S1: Build a three-furnace transfer atmosphere annealing furnace mechanism and 2-3 four-furnace transfer composite magnetic field annealing furnace mechanisms. The atmosphere annealing furnace mechanism and the input end of each three-furnace transfer composite magnetic field annealing furnace mechanism are gathered around a transfer machine. The three-furnace transfer atmosphere annealing furnace mechanism includes a feed inlet, a first heating and insulation furnace, a second heating and insulation furnace, and an annealing furnace. The four-furnace transfer composite magnetic field annealing furnace mechanism includes a second feed inlet, an atmosphere annealing furnace, an atmosphere heating and insulation furnace, a longitudinal magnetic field and a transverse magnetic field switching furnace, and a second annealing furnace.

[0006] S2: Firstly, the iron-based nanocrystalline strip is surface treated, and then the strip is wound into a magnetic core using a constant tension winding machine, and the magnetic cores are arranged in order in a heat treatment box. A robot is used to take the heat treatment box and put it into the box rack placed on the feeding inlet of the three-furnace transfer atmosphere annealing furnace mechanism, and then it is transferred to the first heating and insulation furnace for rapid heating for 15-20 minutes to 390-420°C, and then it is kept at 390-420°C for 15-20 minutes. After the insulation is completed, the new heat treatment box on the box rack placed on the feeding inlet is simultaneously transferred to the first heating and insulation furnace for the same insulation and heating, and at the same time, the heat treatment box in the first heating and insulation furnace is transferred to the second heating and insulation furnace. The box is first quickly heated up for 15-20 minutes to 450-470°C in the second heating and insulation furnace, and then kept at 450-470°C for 15-20 minutes. The heat-treated box after the second heating and insulation furnace is transported to the annealing furnace, and the temperature is automatically reduced for 15-20 minutes in the furnace to 300-350°C, and then the annealing furnace is cooled for 15-20 minutes to 180-200°C, and then transported to the feeding inlet position, and the first heating and insulation furnace and the second heating and insulation furnace are also cyclically operated according to the above method, and the feeding inlet, the first heating and insulation furnace, the second heating and insulation furnace and the annealing furnace are a four-station cyclic transfer station;

[0007] S3: After the heat treatment box annealed in the annealing furnace in step S2 is transported to the feeding inlet position, the heat treatment box after the annealing of the magnetic core is clamped by the robot and placed on the feeding inlet placement box rack of the second feeding inlet of a three-furnace transfer composite magnetic field annealing furnace mechanism, and then transferred to the atmosphere annealing furnace for 50-60 minutes of heating, heating to 480-520°C, and then kept at 480-520°C for 50-60 minutes, and the heat treatment box in the atmosphere annealing furnace is transported to the atmosphere heating and holding furnace, and first heated for 15-20 minutes to 55 0-570℃, keep warm for 80-100min, then transfer to the longitudinal magnetic field and transverse magnetic field switching furnace, apply longitudinal magnetic field treatment, turn off the longitudinal magnetic current after the temperature drops to 490-510℃, cool down for 15-20min, then start the transverse magnetic field in the longitudinal magnetic field and transverse magnetic field switching furnace, keep warm at 490-510℃ for 80-100min, transfer to the second annealing furnace for cooling, cool to 180-200℃, cool down for 100-120min, then transfer to the second feeding inlet, take out the heat treatment box of the nanocrystalline magnetic core, and cool it to room temperature quickly;

[0008] S4: Since the reaction time of a cycle of the four-furnace transfer composite magnetic field annealing furnace mechanism is more than twice that of the three-furnace transfer atmosphere annealing furnace mechanism, more than two four-furnace transfer composite magnetic field annealing furnace mechanisms are set up. When a heat treatment box comes out of the three-furnace transfer atmosphere annealing furnace mechanism again, it will be transferred to another four-furnace transfer composite magnetic field annealing furnace mechanism for demagnetization annealing treatment.

[0009] In some embodiments of the present invention, the three-furnace transfer atmosphere annealing furnace mechanism includes a circular running track, the feed inlet, the first heating and insulation furnace, the second heating and insulation furnace and the annealing furnace are respectively and evenly arranged on the circular running track, the feed inlet, the first heating and insulation furnace, the second heating and insulation furnace and the annealing furnace are respectively and evenly arranged on the circular running track, the feed inlet, the first heating and insulation furnace, the second heating and insulation furnace and the annealing furnace are provided with sealed channels, and the sealed channels at the inlet and outlet ends of the feed inlet, the first heating and insulation furnace, the second heating and insulation furnace and the annealing furnace are provided with channel blocking and opening components, a circular runner is provided on the circular running track, the upper surface of the circular runner is exposed to the upper surface of the circular running track, four feed inlets are arranged at equal intervals on the circular runner for placing box racks, an opening is provided on the circular running track at the feed inlet position to expose the bottom of the circular runner, a gear belt is provided at the bottom of the circular runner, a servo motor drives the gear plate to rotate, and the gear plate is engaged with the gear belt to drive the circular runner to rotate at a fixed distance;

[0010] The four-furnace transfer composite magnetic field annealing furnace mechanism also includes a circular running track with the same structure, but five material inlets are evenly arranged on the circular running track in the four-furnace transfer composite magnetic field annealing furnace mechanism for placing box racks, and the second material inlet, atmosphere annealing furnace, atmosphere heating and insulation furnace, longitudinal magnetic field and transverse magnetic field switching furnace and second annealing furnace are evenly arranged on the circular running track, and a sealing channel and a channel blocking and opening component are also arranged on the circular running track in the four-furnace transfer composite magnetic field annealing furnace mechanism;

[0011] The channel blocking and opening assembly includes two lifting cylinders, a pull plate and a blocking plate. The cylinder shaft ends of the two lifting cylinders are fixed at both ends of the pull plate. The bottom of the pull plate is connected to the top edge of the blocking plate through two connecting rods. The blocking plate is movably inserted into the sealing channel to block the sealing channel.

[0012] In some other embodiments of the present invention, the first heating and holding furnace is first heated to 250°C-280°C when it is turned on, and then the first heat treatment box is pushed in, and the heat treatment box is automatically heated for 8-10 minutes, and the first heating and holding furnace is quickly heated to 390-420°C, so that the heat treatment box is quickly heated to 390-420°C, and then kept warm for 15-20 minutes;

[0013] When the second heat treatment box enters the first heating and insulation furnace at room temperature, the temperature in the first heating and insulation furnace is 390-420℃. After entering, the first heating and insulation furnace is quickly cooled down to 250℃-280℃, and then kept warm for 6-7min, and then quickly heated up to 390-420℃, and then kept warm for 15-20min;

[0014] When the third heat treatment box enters the first heating and insulation furnace at room temperature, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is followed.

[0015] In some other embodiments of the present invention, when the first heat treatment box enters the second heating and holding furnace, the temperature inside the second heating and holding furnace is 390-420°C, and after water enters, the temperature is rapidly increased for 15-20 minutes to 450-470°C, and then kept at 450-470°C for 15-20 minutes;

[0016] When the second heat treatment box enters the second heating and holding furnace at room temperature, the second heating and holding furnace is rapidly cooled to 410-430°C, and then rapidly heated to 450-470°C for 10-15 minutes, and then kept at 450-470°C for 15-20 minutes;

[0017] When the third heat treatment box enters the second heating and insulation furnace at room temperature, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is followed.

[0018] In other embodiments of the present invention, when the first heat treatment box enters the annealing furnace, the temperature in the annealing furnace is 280-300°C, the first heat treatment box is naturally cooled in the furnace for 15-20 minutes, and then the annealing furnace temperature is quickly reduced to 180-200°C, and the first heat treatment box is cooled again to 180-200°C, and the cooling time is 15-20 minutes;

[0019] When the second heat treatment box enters the annealing furnace at room temperature, the temperature in the annealing furnace rises rapidly to 280-300°C, and the heat treatment box is cooled naturally. The annealing furnace is cooled rapidly by 180-200°C, and the heat treatment box continues to cool for 15-20 minutes.

[0020] When the third heat treatment box enters the annealing furnace at room temperature, it is cooled down according to the treatment method of the second heat treatment box, and the operation cycle of the second heat treatment box is followed.

[0021] In other embodiments of the present invention, when the first heat treatment box enters the atmosphere annealing furnace, the temperature in the atmosphere annealing furnace is 350-380°C, and then the first heat treatment box is pushed in, and the heat treatment box is automatically heated up for 15-20 minutes, and the atmosphere annealing furnace is heated to 480-520°C, and the heating time is 35-45 minutes, so that the heat treatment box is heated to 480-520°C, and then kept warm for 50-60 minutes;

[0022] When the second heat treatment box enters the atmosphere annealing furnace at room temperature, the temperature in the atmosphere annealing furnace is 480-520°C. After entering, the atmosphere annealing furnace is first cooled down rapidly to 350-380°C, and the heat treatment box is automatically heated up for 12-15 minutes. Then, the atmosphere annealing furnace is heated up to 480-520°C, and the heating time is 35-45 minutes, and then the temperature is kept for 50-60 minutes.

[0023] When the third heat treatment box enters the atmosphere annealing furnace at room temperature, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is performed.

[0024] In other embodiments of the present invention, the first heat treatment box enters the atmosphere heating and insulation furnace, the temperature in the atmosphere heating and insulation furnace is heated to 480-520°C, and the temperature is first increased for 15-20 minutes, the temperature is increased to 550-570°C, and the temperature is kept for 80-100 minutes, and then the box is transferred to the longitudinal magnetic field and transverse magnetic field switching furnace;

[0025] When the second heat treatment box enters the atmosphere heating and holding furnace, the temperature in the atmosphere heating and holding furnace quickly drops from 550-570℃ to 510-520℃, and then heats up for 12-18min to 550-570℃, keeps warm for 80-100min, and then is transferred to the longitudinal magnetic field and transverse magnetic field switching furnace;

[0026] When the third heat treatment box enters the atmosphere heating and insulation furnace, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is carried out.

[0027] In other embodiments of the present invention, the first heat treatment box enters the atmosphere heating and insulation furnace, the temperature in the atmosphere heating and insulation furnace is heated to 480-520°C, and the temperature is first increased for 15-20 minutes, the temperature is increased to 550-570°C, and the temperature is kept for 80-100 minutes, and then the box is transferred to the longitudinal magnetic field and transverse magnetic field switching furnace;

[0028] When the second heat treatment box enters the atmosphere heating and holding furnace, the temperature in the atmosphere heating and holding furnace quickly drops from 550-570℃ to 510-520℃, and then heats up for 12-18min to 550-570℃, keeps warm for 80-100min, and then is transferred to the longitudinal magnetic field and transverse magnetic field switching furnace;

[0029] When the third heat treatment box enters the atmosphere heating and insulation furnace, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is carried out.

[0030] In the present invention, each reaction step is carried out in an independent furnace. When a large temperature increase or temperature decrease is required, the reaction step is directly transferred to the next furnace body for temperature increase or temperature decrease, so as to reduce the serious heat loss caused by the large temperature change in each furnace body. At the same time, the problem of excessive accumulation of iron-based nanocrystalline magnetic cores in a large reaction furnace, resulting in poor temperature control in the furnace, fast temperature decrease and temperature increase near the furnace wall, and relatively slow temperature decrease and temperature increase of the iron-based nanocrystalline magnetic core in the center, resulting in different reaction conditions of an iron-based nanocrystalline magnetic core, is solved. In addition, continuous reaction is carried out, and the heat treatment efficiency is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0032] Figure 1 This is a schematic structural diagram of the three-furnace transfer atmosphere annealing furnace mechanism proposed by the present invention.

[0033] Figure 2This is a schematic structural diagram of the circular operating track and the circular rotating track proposed in the present invention.

[0034] Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure.

[0035] In the figure: 1. First heating and holding furnace; 2. Second heating and holding furnace; 3. Annealing furnace; 4. Sealed channel; 41. Annular running track; 42. Annular turntable; 5. Channel blocking and opening components; 51. Lifting cylinder; 52. Pull plate; 521. Blocking plate; 6. Feed inlet; 7. Servo motor; 71. Gear plate; 8. Box rack for placing the feed inlet. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0037] The present invention proposes a method for heat treatment of residual magnetism of an iron-based nanocrystalline magnetic core, and the specific method is as follows:

[0038] S1: Build a three-furnace transfer atmosphere annealing furnace mechanism and 2-3 four-furnace transfer composite magnetic field annealing furnace mechanisms, the atmosphere annealing furnace mechanism and the input end of each three-furnace transfer composite magnetic field annealing furnace mechanism are gathered around a transfer machine, the three-furnace transfer atmosphere annealing furnace mechanism includes a feed inlet 6, a first heating and insulation furnace 1, a second heating and insulation furnace 2 and an annealing furnace 3, and the four-furnace transfer composite magnetic field annealing furnace mechanism includes a second feed inlet, an atmosphere annealing furnace, an atmosphere heating and insulation furnace, a longitudinal magnetic field and a transverse magnetic field switching furnace and a second annealing furnace;

[0039] The heat treatment reaction is mainly carried out in two furnace bodies. The first heating annealing treatment is carried out in the three-furnace transfer atmosphere annealing furnace mechanism. After that, the longitudinal magnetic field and transverse magnetic field remanence heat treatment is required. The overall time of the four-furnace transfer composite magnetic field annealing furnace mechanism is relatively long. A 2-3 matching three-furnace transfer composite magnetic field annealing furnace mechanism is set up.

[0040] S2: Firstly, the iron-based nanocrystalline strip is surface treated, and then the constant tension winding machine is used to wind the strip into a magnetic core, and the magnetic core is orderly arranged in a heat treatment box, and the heat treatment box is taken by a robot and placed on the box rack 8 for placing the material inlet of the three-furnace transfer atmosphere annealing furnace mechanism, and then transferred to the first heating and insulation furnace 1, and the temperature is rapidly increased for 15-20 minutes to 390-420℃, and then kept at 390-420℃ for 15-20 minutes. After the insulation is completed, the new heat treatment box on the box rack 8 for placing the material inlet is simultaneously transferred to the first heating and insulation furnace 1 for the same insulation and heating, and at the same time, the heat treatment box in the first heating and insulation furnace 1 is transferred to the second heating and insulation furnace 2, and the heat treatment box is in The heat treatment box is transferred to the second heating and holding furnace 2 for 15-20 minutes of rapid heating to 450-470°C, and then kept at 450-470°C for 15-20 minutes. The heat treatment box after the second heating and holding furnace 2 is kept will be transferred to the annealing furnace 3, and the temperature in the furnace is automatically reduced for 15-20 minutes to 300-350°C, and then the annealing furnace 3 is cooled for 15-20 minutes to 180-200°C, and then transferred to the feeding inlet 6 position, and the first heating and holding furnace 1 and the second heating and holding furnace 2 are also cyclically operated according to the above method, and the feeding inlet 6, the first heating and holding furnace 1, the second heating and holding furnace 2 and the annealing furnace 3 are a four-station cyclic transfer station;

[0041] The three-furnace transfer atmosphere annealing furnace structure is divided into multiple temperature steps and is divided into four stations according to time periods. If conditions change, 5 stations can be set up.

[0042] S3: After the heat treatment box annealed in the annealing furnace 3 in step S2 is transported to the feeding inlet position, the heat treatment box after the annealing of the magnetic core is clamped by the robot and placed on the feeding inlet placement box rack of the second feeding inlet of a three-furnace transfer composite magnetic field annealing furnace mechanism, and then transferred to the atmosphere annealing furnace for 50-60 minutes of heating, heating to 480-520°C, and then kept at 480-520°C for 50-60 minutes, and the heat treatment box in the atmosphere annealing furnace is transported to the atmosphere heating and holding furnace, and first heated for 15-20 minutes to 55 0-570℃, keep warm for 80-100min, then transfer to the longitudinal magnetic field and transverse magnetic field switching furnace, apply longitudinal magnetic field treatment, turn off the longitudinal magnetic current after the temperature drops to 490-510℃, cool down for 15-20min, then start the transverse magnetic field in the longitudinal magnetic field and transverse magnetic field switching furnace, keep warm at 490-510℃ for 80-100min, transfer to the second annealing furnace for cooling, cool to 180-200℃, cool down for 100-120min, then transfer to the second feeding inlet, take out the heat treatment box of the nanocrystalline magnetic core, and cool it to room temperature quickly;

[0043] In the four-furnace transfer composite magnetic field annealing furnace, the mechanism time is longer, the reaction conditions vary more, and five stations are set, or six stations can be set as needed. Ensure that the reaction time of each station is the same.

[0044] S4: Since the reaction time of a cycle of the four-furnace transfer composite magnetic field annealing furnace mechanism is more than twice that of the three-furnace transfer atmosphere annealing furnace mechanism, more than two four-furnace transfer composite magnetic field annealing furnace mechanisms are set up. When a heat treatment box comes out of the three-furnace transfer atmosphere annealing furnace mechanism again, it will be transferred to another four-furnace transfer composite magnetic field annealing furnace mechanism for demagnetization annealing treatment.

[0045] The three-furnace transfer atmosphere annealing furnace mechanism includes a circular running track, the feed inlet 6, the first heating and insulation furnace 1, the second heating and insulation furnace 2 and the annealing furnace 3 are respectively and evenly arranged on the circular running track 41, the feed inlet 6, the first heating and insulation furnace 1, the second heating and insulation furnace 2 and the annealing furnace are provided with a sealed channel 4 on the circular running track 41 between the feed inlet 6, the first heating and insulation furnace 1, the second heating and insulation furnace 2 and the annealing furnace, and the feed inlet 6, the first heating and insulation furnace 1, the second heating and insulation furnace 2 and the annealing furnace are provided with channel plugging and Open the assembly 5, a circular runner 42 is provided on the circular running track 41, the upper surface of the circular runner 42 is exposed to the upper surface of the circular running track 41, four material feeding ports are arranged at equal intervals on the circular runner 42 to place the box rack 8, an opening is arranged at the bottom of the circular running track 41 at the position of the material feeding port 6 to expose the bottom of the circular runner 42, a gear belt is arranged at the bottom of the circular runner 42, a gear plate 71 is driven to rotate by a servo motor 7, and the gear plate 71 is meshed with the gear belt to drive the circular runner 42 to rotate at a fixed distance;

[0046] The circular turntable 42 on the circular operating track drives the gear plate 71 through the servo motor 7 to perform fixed-distance transfer, thereby realizing synchronous transfer of multiple workstations. Two channel blocking and opening components are also provided at the feed inlet 6. After each transfer, the sealed channels 4 on both sides of the feed inlet 6 can replace the inert gas to prevent part of the air from flowing into the furnace after entering.

[0047] The inner ring pitch of the gear belt should be smaller than the outer ring pitch, so the gear plate 71 should also be designed to appropriately change the pitch effect for driving.

[0048] The four-furnace transfer composite magnetic field annealing furnace mechanism also includes a circular running track with the same structure, but five material inlets are evenly arranged on the circular running track in the four-furnace transfer composite magnetic field annealing furnace mechanism for placing box racks, and the second material inlet, atmosphere annealing furnace, atmosphere heating and insulation furnace, longitudinal magnetic field and transverse magnetic field switching furnace and second annealing furnace are evenly arranged on the circular running track, and a sealing channel and a channel blocking and opening component are also arranged on the circular running track in the four-furnace transfer composite magnetic field annealing furnace mechanism;

[0049] The channel blocking and opening assembly includes two lifting cylinders 51, a pull plate 52 and a blocking plate 521. The cylinder shaft ends of the two lifting cylinders 51 are fixed to the two ends of the pull plate. The bottom of the pull plate 52 is connected to the top edge of the blocking plate 521 through two connecting rods. The blocking plate 521 is movably inserted into the sealing channel 4 to block the sealing channel 4. During each transfer, all the blocking plates 521 are opened at the same time, and are immediately blocked after the transfer is completed.

[0050] The first heating and insulation furnace 1 is first heated to 250°C-280°C when it is turned on, and then the first heat treatment box is pushed in, and the heat treatment box is automatically heated for 8-10 minutes, and the first heating and insulation furnace 1 is quickly heated to 390-420°C, so that the heat treatment box is quickly heated to 390-420°C, and then kept warm for 15-20 minutes;

[0051] When the second heat treatment box enters the first heating and insulation furnace 1 at room temperature, the temperature in the first heating and insulation furnace 1 is 390-420°C. After entering, the first heating and insulation furnace 1 is rapidly cooled to 250-280°C, then kept warm for 6-7 minutes, and then rapidly heated to 390-420°C, and then kept warm for 15-20 minutes;

[0052] When the third heat treatment box enters the first temperature rising and holding furnace 1 at room temperature, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is followed.

[0053] It is possible to achieve slight changes in the temperature inside the furnace without consuming too much energy to cool down or heat up, and then transfer to the next furnace to use the temperature inside the next furnace for further reaction.

[0054] When the first heat treatment box enters the second heating and holding furnace 2, the temperature in the second heating and holding furnace 2 is 390-420°C. After water enters, the temperature is rapidly increased for 15-20 minutes to 450-470°C, and then kept at 450-470°C for 15-20 minutes.

[0055] When the second heat treatment box enters the second heating and holding furnace 2 at room temperature, the second heating and holding furnace 2 is rapidly cooled to 410-430°C, then rapidly heated to 450-470°C for 10-15 minutes, and then kept at 450-470°C for 15-20 minutes;

[0056] When the third heat treatment box enters the second heating and insulation furnace 2 at room temperature, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is followed.

[0057] Likewise, slight changes in the furnace temperature can be achieved without consuming too much energy to cool or heat it, and it can be transferred to the next furnace and further reacted at the temperature of the next furnace.

[0058] When the first heat treatment box enters the annealing furnace 3, the temperature in the annealing furnace 3 is 280-300°C, the first heat treatment box is cooled naturally in the furnace for 15-20 minutes, and then the temperature of the annealing furnace 3 is quickly reduced to 180-200°C, and the first heat treatment box is cooled again to 180-200°C, and the cooling time is 15-20 minutes;

[0059] When the second heat treatment box enters the annealing furnace 3 at room temperature, the temperature in the annealing furnace 3 rises rapidly to 280-300°C, and the heat treatment box is cooled naturally. The annealing furnace is cooled rapidly by 180-200°C, and the heat treatment box continues to cool for 15-20 minutes.

[0060] After the third heat treatment box enters the annealing furnace 3 at room temperature, it is cooled down according to the treatment method of the second heat treatment box, and the operation cycle of the second heat treatment box is followed.

[0061] When the first heat treatment box enters the atmosphere annealing furnace, the temperature in the atmosphere annealing furnace is 350-380°C, and then the first heat treatment box is pushed in, and the heat treatment box is automatically heated up for 15-20 minutes, and the atmosphere annealing furnace is heated to 480-520°C. The heating time is 35-45 minutes, so that the heat treatment box is heated to 480-520°C, and then kept warm for 50-60 minutes;

[0062] When the second heat treatment box enters the atmosphere annealing furnace at room temperature, the temperature in the atmosphere annealing furnace is 480-520°C. After entering, the atmosphere annealing furnace is first cooled down rapidly to 350-380°C, and the heat treatment box is automatically heated up for 12-15 minutes. Then, the atmosphere annealing furnace is heated up to 480-520°C, and the heating time is 35-45 minutes, and then the temperature is kept for 50-60 minutes.

[0063] When the third heat treatment box enters the atmosphere annealing furnace at room temperature, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is performed.

[0064] The temperature in the furnace can be slightly changed without consuming too much energy to cool down or heat up, and then transferred to the next furnace for further reaction at the temperature in the next furnace. The temperature can be reduced without significantly reducing the temperature in the furnace, but only by a small change.

[0065] The first heat treatment box enters the atmosphere heating and insulation furnace, and the temperature in the atmosphere heating and insulation furnace is heated to 480-520℃. It is heated for 15-20 minutes, then heated to 550-570℃, and kept warm for 80-100 minutes, and then transferred to the longitudinal magnetic field and transverse magnetic field switching furnace;

[0066] When the second heat treatment box enters the atmosphere heating and holding furnace, the temperature in the atmosphere heating and holding furnace quickly drops from 550-570℃ to 510-520℃, and then heats up for 12-18min to 550-570℃, keeps warm for 80-100min, and then is transferred to the longitudinal magnetic field and transverse magnetic field switching furnace;

[0067] When the third heat treatment box enters the atmosphere heating and insulation furnace, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is carried out.

[0068] The first heat treatment box enters the longitudinal magnetic field and transverse magnetic field switching furnace, the temperature in the longitudinal magnetic field and transverse magnetic field switching furnace is heated to 550-570℃, the longitudinal magnetic field treatment is applied, the longitudinal magnetic current is turned off after the temperature drops to 490-510℃, the cooling treatment time is 15-20min, then the transverse magnetic field is started in the longitudinal magnetic field and transverse magnetic field switching furnace, after keeping the temperature at 490-510℃ for 80-100min, it is transferred to the second annealing furnace for cooling;

[0069] When the second heat treatment box enters the longitudinal magnetic field and transverse magnetic field switching furnace, the temperature in the longitudinal magnetic field and transverse magnetic field switching furnace is rapidly heated to 550-570°C, and at the same time, the longitudinal magnetic field treatment is applied. After the temperature drops to 490-510°C, the longitudinal magnetic current is turned off, and the cooling treatment time is 12-18 minutes. Then, the transverse magnetic field is started in the longitudinal magnetic field and transverse magnetic field switching furnace, and after keeping the temperature at 490-510°C for 80-100 minutes, it is transferred to the second annealing furnace for cooling;

[0070] When the third heat treatment box enters the longitudinal magnetic field and transverse magnetic field switching furnace, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is performed.

[0071] The temperature drop and temperature rise of each furnace in the four-furnace transfer composite magnetic field annealing furnace is small, which will not cause excessive energy loss. The mechanism principle is the same as that of the three-furnace transfer atmosphere annealing furnace.

[0072] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A heat treatment method for residual magnetism of an iron-based nanocrystalline magnetic core, characterized in that: The specific method is as follows: S1: Build a three-furnace transfer atmosphere annealing furnace mechanism and 2-3 four-furnace transfer composite magnetic field annealing furnace mechanisms, the atmosphere annealing furnace mechanism and the input end of each three-furnace transfer composite magnetic field annealing furnace mechanism are gathered around a transfer machine, the three-furnace transfer atmosphere annealing furnace mechanism includes a material feeding inlet (6), a first heating and insulation furnace (1), a second heating and insulation furnace (2) and an annealing furnace (3), and the four-furnace transfer composite magnetic field annealing furnace mechanism includes a second material feeding inlet, an atmosphere annealing furnace, an atmosphere heating and insulation furnace, a longitudinal magnetic field and a transverse magnetic field switching furnace and the second annealing furnace; S2: Firstly, the iron-based nanocrystalline strip is surface treated, and then the strip is wound into a magnetic core using a constant tension winding machine, and the magnetic cores are orderly arranged in a heat treatment box. The heat treatment box is taken by a robot and placed on the box rack (8) at the material inlet of the three-furnace transfer atmosphere annealing furnace mechanism, and then transferred to the first heating and insulation furnace (1), and the temperature is rapidly increased for 15-20 minutes to 390-420°C, and then the temperature is maintained at 390-420°C for 15-20 minutes. After the insulation is completed, the new heat treatment box on the box rack (8) at the material inlet is simultaneously transferred to the first heating and insulation furnace (1) for the same insulation and heating, and at the same time, the heat treatment box in the first heating and insulation furnace (1) is transferred to the second heating and insulation furnace (2). The heat treatment box is transferred to the first The second heating and holding furnace (2) is first heated up quickly for 15-20 minutes to 450-470°C, and then kept at 450-470°C for 15-20 minutes. The heat treatment box that has been kept in the second heating and holding furnace (2) is transferred to the annealing furnace (3), and the temperature is automatically reduced for 15-20 minutes in the furnace to 300-350°C, and then the annealing furnace (3) is cooled for 15-20 minutes to 180-200°C, and then transferred to the feeding port (6). The first heating and holding furnace (1) and the second heating and holding furnace (2) are also cyclically operated according to the above method. The feeding port (6), the first heating and holding furnace (1), the second heating and holding furnace (2) and the annealing furnace (3) form a four-station cyclic transfer station. S3: After the heat treatment box annealed in the annealing furnace (3) in step S2 is transported to the feed inlet position, the heat treatment box after annealing the magnetic core is clamped by a robot and placed on the box rack of the second feed inlet of a three-furnace transfer composite magnetic field annealing furnace mechanism, and is rapidly cooled to room temperature, and then transferred to the atmosphere annealing furnace for 50-60 minutes of heating, heating to 480-520°C, and then kept at 480-520°C for 50-60 minutes, and the heat treatment box in the atmosphere annealing furnace is transported to the atmosphere heating and holding furnace, and first heated for 15-20 minutes, and heated to 5 50-570℃, keep warm for 80-100min, then transfer to the longitudinal magnetic field and transverse magnetic field switching furnace, apply longitudinal magnetic field treatment, turn off the longitudinal magnetic current after the temperature drops to 490-510℃, cool down for 15-20min, then start the transverse magnetic field in the longitudinal magnetic field and transverse magnetic field switching furnace, keep warm at 490-510℃ for 80-100min, transfer to the second annealing furnace for cooling, cool to 180-200℃, cool down for 100-120min, then transfer to the second feeding inlet, take out the heat treatment box of the nanocrystalline magnetic core, and quench to room temperature; S4: Since the reaction time of a cycle of the four-furnace transfer composite magnetic field annealing furnace mechanism is more than twice that of the three-furnace transfer atmosphere annealing furnace mechanism, more than two four-furnace transfer composite magnetic field annealing furnace mechanisms are set up. When a heat treatment box comes out of the three-furnace transfer atmosphere annealing furnace mechanism again, it will be transferred to another four-furnace transfer composite magnetic field annealing furnace mechanism for demagnetization annealing treatment.

2. The heat treatment method for residual magnetism of an iron-based nanocrystalline magnetic core according to claim 1, characterized in that: The three-furnace transfer atmosphere annealing furnace mechanism comprises a circular running track, wherein the feed inlet (6), the first heating and insulation furnace (1), the second heating and insulation furnace (2) and the annealing furnace (3) are respectively and evenly arranged on the circular running track (41), and the feed inlet (6), the first heating and insulation furnace (1), the second heating and insulation furnace (2) and the annealing furnace are provided with a sealing channel (4) between the feed inlet (6), the first heating and insulation furnace (1), the second heating and insulation furnace (2) and the annealing furnace, and the sealing channels at the inlet and outlet ends of the feed inlet (6), the first heating and insulation furnace (1), the second heating and insulation furnace (2) and the annealing furnace (3) are provided with channel plugging and opening devices. An opening assembly (5) is provided on the annular running track (41), an annular turntable (42) is exposed on the upper surface of the annular turntable (42), four material inlet ports are provided at equal intervals on the annular turntable (42) to place a box frame (8), an opening is provided at the bottom of the annular running track (41) at the position of the material inlet port (6) to expose the bottom of the annular turntable (42), a gear belt is provided at the bottom of the annular turntable (42), a gear plate (71) is driven to rotate by a servo motor (7), and the gear plate (71) is meshed with the gear belt to drive the annular turntable (42) to rotate at a fixed distance; The four-furnace transfer composite magnetic field annealing furnace mechanism also includes a circular running track with the same structure, but five material inlets are evenly arranged on the circular running track in the four-furnace transfer composite magnetic field annealing furnace mechanism for placing box racks, and the second material inlet, atmosphere annealing furnace, atmosphere heating and insulation furnace, longitudinal magnetic field and transverse magnetic field switching furnace and second annealing furnace are evenly arranged on the circular running track, and a sealing channel and a channel blocking and opening component are also arranged on the circular running track in the four-furnace transfer composite magnetic field annealing furnace mechanism; The channel blocking and opening assembly comprises two lifting cylinders (51), a pull plate (52) and a blocking plate (521), the cylinder shaft ends of the two lifting cylinders (51) are fixed at both ends of the pull plate, the bottom of the pull plate (52) is connected to the top edge of the blocking plate (521) through two connecting rods, and the blocking plate (521) is movably inserted into the sealing channel (4) to block the sealing channel (4).

3. The heat treatment method for residual magnetism of an iron-based nanocrystalline magnetic core according to claim 1, characterized in that: When the first heating and insulation furnace (1) is turned on, it is first heated to 250°C-280°C, and then the first heat treatment box is pushed in, and the heat treatment box is automatically heated for 8-10 minutes, and the first heating and insulation furnace (1) is quickly heated to 390-420°C, so that the heat treatment box is quickly heated to 390-420°C, and then the temperature is kept for 15-20 minutes; When the second heat treatment box enters the first heating and insulation furnace (1) at room temperature, the temperature in the first heating and insulation furnace (1) is at 390-420°C. After entering, the first heating and insulation furnace (1) is firstly cooled down rapidly to 250-280°C, then kept at this temperature for 6-7 minutes, and then quickly heated up to 390-420°C, and then kept at this temperature for 15-20 minutes; When the third heat treatment box enters the first heating and insulation furnace (1) at room temperature, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is followed.

4. The heat treatment method for residual magnetism of an iron-based nanocrystalline magnetic core according to claim 1, characterized in that: When the first heat treatment box enters the second heating and holding furnace (2), the temperature in the second heating and holding furnace (2) is 390-420°C. After water enters, the temperature is rapidly increased for 15-20 minutes to 450-470°C, and then kept at 450-470°C for 15-20 minutes; After the second heat treatment box enters the second heating and insulation furnace (2) at room temperature, the second heating and insulation furnace (2) is rapidly cooled to 410-430° C., then rapidly heated to 450-470° C. for 10-15 minutes, and then kept at 450-470° C. for 15-20 minutes; When the third heat treatment box enters the second heating and insulation furnace (2) at room temperature, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is followed.

5. The heat treatment method for residual magnetism of an iron-based nanocrystalline magnetic core according to claim 1, characterized in that: When the first heat treatment box enters the annealing furnace (3), the temperature in the annealing furnace (3) is 280-300°C, the first heat treatment box is cooled naturally in the furnace for 15-20 minutes, and then the temperature of the annealing furnace (3) is quickly reduced to 180-200°C, and the first heat treatment box is cooled again to 180-200°C, and the cooling time is 15-20 minutes; When the second heat treatment box enters the annealing furnace (3) at room temperature, the temperature in the annealing furnace (3) is rapidly raised to 280-300°C, and the temperature of the heat treatment box is naturally lowered. The annealing furnace is then rapidly lowered by 180-200°C, and the heat treatment box continues to be lowered for 15-20 minutes. When the third heat treatment box enters the annealing furnace (3) at room temperature, it is subjected to a temperature reduction treatment in accordance with the treatment method of the second heat treatment box, and the operation cycle of the second heat treatment box is followed.

6. The heat treatment method for residual magnetism of an iron-based nanocrystalline magnetic core according to claim 1, characterized in that: When the first heat treatment box enters the atmosphere annealing furnace, the temperature in the atmosphere annealing furnace is 350-380°C, and then the first heat treatment box is pushed in, and the heat treatment box is automatically heated up for 15-20 minutes, and the atmosphere annealing furnace is heated to 480-520°C. The heating time is 35-45 minutes, so that the heat treatment box is heated to 480-520°C, and then kept warm for 50-60 minutes; When the second heat treatment box enters the atmosphere annealing furnace at room temperature, the temperature in the atmosphere annealing furnace is 480-520°C. After entering, the atmosphere annealing furnace is first cooled down rapidly to 350-380°C, and the heat treatment box is automatically heated up for 12-15 minutes. Then, the atmosphere annealing furnace is heated up to 480-520°C, and the heating time is 35-45 minutes, and then the temperature is kept for 50-60 minutes. When the third heat treatment box enters the atmosphere annealing furnace at room temperature, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is performed.

7. The heat treatment method for residual magnetism of an iron-based nanocrystalline magnetic core according to claim 1, characterized in that: The first heat treatment box enters the atmosphere heating and insulation furnace, and the temperature in the atmosphere heating and insulation furnace is heated to 480-520℃. It is heated for 15-20 minutes, then heated to 550-570℃, and kept warm for 80-100 minutes, and then transferred to the longitudinal magnetic field and transverse magnetic field switching furnace; When the second heat treatment box enters the atmosphere heating and holding furnace, the temperature in the atmosphere heating and holding furnace quickly drops from 550-570℃ to 510-520℃, and then heats up for 12-18min to 550-570℃, keeps warm for 80-100min, and then is transferred to the longitudinal magnetic field and transverse magnetic field switching furnace; When the third heat treatment box enters the atmosphere heating and insulation furnace, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is carried out.

8. The heat treatment method for residual magnetism of an iron-based nanocrystalline magnetic core according to claim 1, characterized in that: The first heat treatment box enters the longitudinal magnetic field and transverse magnetic field switching furnace, the temperature in the longitudinal magnetic field and transverse magnetic field switching furnace is heated to 550-570℃, the longitudinal magnetic field treatment is applied, the longitudinal magnetic current is turned off after the temperature drops to 490-510℃, the cooling treatment time is 15-20min, then the transverse magnetic field is started in the longitudinal magnetic field and transverse magnetic field switching furnace, after keeping the temperature at 490-510℃ for 80-100min, it is transferred to the second annealing furnace for cooling; When the second heat treatment box enters the longitudinal magnetic field and transverse magnetic field switching furnace, the temperature in the longitudinal magnetic field and transverse magnetic field switching furnace is rapidly heated to 550-570°C, and at the same time, the longitudinal magnetic field treatment is applied. After the temperature drops to 490-510°C, the longitudinal magnetic current is turned off, and the cooling treatment time is 12-18 minutes. Then, the transverse magnetic field is started in the longitudinal magnetic field and transverse magnetic field switching furnace, and after keeping the temperature at 490-510°C for 80-100 minutes, it is transferred to the second annealing furnace for cooling; When the third heat treatment box enters the longitudinal magnetic field and transverse magnetic field switching furnace, it is heated according to the treatment method of the second heat treatment box and the operation cycle of the second heat treatment box is followed.

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