Magnetic conductive insulating rod for induction coil of intermediate frequency furnace

Abstract

The invention discloses a magnetic conductive insulating rod for an induction coil of an intermediate frequency furnace in the technical field of induction materials of the intermediate frequency furnace. The magnetic conductive insulating rod comprises 77-86.5 wt% of nickel zinc ferrite magnetic powder; 10 to 15 wt% of fumed silica powder; 1 to 5 wt% of mica fine powder; 0.001 to 0.005 wt% of a modified glass fiber; 0.5 to 3 wt% of polyimide; the magnetic conductive insulating rod for the intermediate frequency furnace induction coil is high in mechanical strength, has magnetic conductivity, can improve the overall magnetic induction efficiency of the induction coil, and has a certain energy-saving effect.

Description

Technical Field

[0001] The present invention relates to the technical field of medium frequency induction furnace materials, in particular to a magnetic conductive insulating rod for a medium frequency furnace induction coil. Background Art

[0002] Medium-frequency induction furnaces are a type of high-temperature smelting equipment commonly used in the steel and foundry industries. They feature rapid heating rates, intermittent operation, ease of operation, minimal pollution, and high energy efficiency. To improve the magnetic efficiency of the induction coil, existing steel-shell furnaces typically use a magnetic yoke made of stacked silicon steel sheets wrapped around the outside of the induction coil, creating a closed magnetic loop.

[0003] Since the induction coil needs to be fixed with multiple epoxy rods around it, which takes up a lot of space, the magnetic yoke cannot be fully covered, and the coverage rate is only 80%. The ideal coverage rate is 100%, which is the best effect. Therefore, it is necessary to develop a magnetic insulating rod for the induction coil of the medium frequency furnace to replace the conventional epoxy rod that cannot conduct magnetism to fill this defect. Summary of the Invention

[0004] In order to overcome the deficiencies in the background technology, the present invention discloses a magnetic conductive insulating rod for an induction coil of a medium frequency furnace.

[0005] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions: A magnetic conductive insulating rod for an induction coil of a medium frequency furnace, comprising a powder and modified glass fiber accounting for 0.001 to 0.005 wt% of the powder; the powder comprises: 77 to 86.5 wt% of nickel-zinc ferrite magnetic powder; 10 to 15 wt% of fumed silica powder; 1 to 5 wt% of mica fine powder; and 0.5 to 3 wt% of polyimide. The preparation method comprises the following steps: mixing the raw materials uniformly, pressing and forming the raw materials, and then baking the raw materials to obtain the product.

[0006] Preferably, the nickel-zinc ferrite magnetic powder has a content of ≥98 wt% and a particle size of ≤100 μm.

[0007] Preferably, the content of the fumed silica powder is ≥99 wt% and the particle size is ≤0.1 μm.

[0008] Preferably, the content of the mica fine powder is ≥99wt%; and the particle size of the mica fine powder is ≤50μm.

[0009] Preferably, the glass fiber has a diameter of 10 to 24 μm and a length of 1 to 3 mm. Preferably, the binder is polyimide.

[0010] Preferably, the stirred material is poured into a mold and placed on a press, a pressure of 100 to 300 MPa is applied, and the molded rod is taken out after the pressure is maintained for 3 to 10 minutes. Preferably, the pressure-formed rods are baked in an oven at 300° C. for 1 hour and kept warm for 2 to 4 hours.

[0011] Due to the adoption of the above-mentioned technical solution, the present invention has the following beneficial effects: The present invention uses nickel-zinc ferrite soft magnetic powder as the main material, and its resistivity is relatively high among soft magnetic materials. 5 ~10 8 Ω / m. To further enhance resistivity, fumed silica and mica powder are added. After thorough stirring, they are evenly distributed around the ferrite powder, effectively increasing resistivity and improving the material's overall heat resistance. Modified glass fiber is added to enhance the material's mechanical properties, making it crack-resistant. Using polyimide as an adhesive offers superior mechanical properties and high-temperature resistance. The magnetically conductive insulating rod for the induction coil of a medium-frequency furnace disclosed herein can improve the overall magnetic induction efficiency of the induction coil, resulting in a certain energy-saving effect.

[0012] The present invention discloses a magnetic insulating rod for a medium frequency furnace induction coil, which has magnetic conductivity and fills the space occupied by the epoxy rod that cannot be covered by the magnetic yoke, thereby increasing the coverage area of ​​the magnetic conductor as a whole and significantly improving the magnetic induction efficiency. DETAILED DESCRIPTION

[0013] The present invention can be explained in detail by the following examples, the purpose of which is to disclose the present invention and to protect all technical improvements within the scope of the present invention. Example 1

[0014] 77 wt% of nickel-zinc ferrite magnetic powder, 15 wt% of fumed silica powder, 5 wt% of mica fine powder, 3 wt% of polyimide, and 0.005 wt% of modified glass fiber were mixed and stirred uniformly. The casting mold was placed on a press, and a pressure of 100 MPa was applied. After maintaining the pressure for 3 minutes, the formed rod was taken out and baked in an oven at 300°C for 1 hour and kept warm for 2 hours. Example 2

[0015] 82wt% nickel-zinc ferrite magnetic powder, 13wt% fumed silica powder, 3wt% mica fine powder, 2wt% polyimide, and 0.003wt% modified glass fiber are mixed and stirred evenly. After pouring into the mold, it is placed on a press and a pressure of 200MPa is applied. After maintaining the pressure for 7 minutes, the formed rod is taken out and baked in an oven at 300℃ for 1 hour and kept warm for 3 hours. Example 3

[0016] 86.5wt% nickel-zinc ferrite magnetic powder, 10wt% fumed silica powder, 2wt% mica fine powder, 1.5wt% polyimide, and 0.002wt% modified glass fiber are mixed and stirred evenly. After pouring into a mold, it is placed on a press and a pressure of 300MPa is applied. After maintaining the pressure for 10 minutes, the formed rod is taken out and baked in an oven at 300℃ for 1 hour and kept warm for 4 hours.

[0017] Comparative Example 1: existing medium frequency furnace epoxy rod.

[0018] It can be seen from Table 1 that compared with Comparative Example 1, Examples 1-3 not only have magnetic conductivity that the prior art does not have, but also have better temperature resistance, insulation and mechanical performance indicators.

[0019]

[0020] Table 1 Performance comparison of Examples 1-3 and Comparative Example 1 The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and it is intended that all changes that fall within the meaning and scope of equivalent elements are included in the present invention.

Claims

1. A magnetic insulating rod for an induction coil of a medium frequency furnace, characterized by: The invention comprises a powder and modified glass fiber accounting for 0.001 to 0.005 wt% of the powder; the powder comprises: 77 to 86.5 wt% of nickel-zinc ferrite magnetic powder; 10 to 15 wt% of fumed silica powder; 1 to 5 wt% of mica fine powder; and 0.5 to 3 wt% of polyimide. The preparation method comprises the following steps: mixing the raw materials uniformly, pressing and forming the raw materials, and then baking the raw materials to obtain the product.

2. The magnetic conductive insulating rod for the induction coil of a medium frequency furnace according to claim 1, characterized in that: The nickel-zinc ferrite magnetic powder has a content of ≥98wt% and a particle size of ≤100μm.

3. The magnetic conductive insulating rod for the induction coil of a medium frequency furnace according to claim 1, characterized in that: The content of the fumed silicon dioxide powder is ≥99wt% and the particle size is ≤0.1μm.

4. The magnetic conductive insulating rod for the induction coil of a medium frequency furnace according to claim 1, characterized in that: The content of the mica fine powder is ≥99wt%; and the particle size of the mica fine powder is ≤50μm.

5. The magnetic conductive insulating rod for the induction coil of a medium frequency furnace according to claim 1, characterized in that: The modified glass fiber has a diameter of 10 to 24 μm and a length of 1 to 3 mm.

6. The magnetic conductive insulating rod for the induction coil of a medium frequency furnace according to claim 1, characterized in that: The pressure molding is to pour the stirred material into a mold and then place it on a press, apply a pressure of 100 to 300 MPa, and maintain the pressure for 3 to 10 minutes.

7. The magnetic conductive insulating rod for the induction coil of a medium frequency furnace according to claim 1, characterized in that: The baking step is to take out the formed rods after press forming, bake them in an oven at 300° C. for 1 hour, and keep them warm for 2 to 4 hours.

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