CN-115475950-B - Flake crushing device of vacuum induction melting furnace and application thereof

Abstract

The invention relates to the auxiliary field of vacuum induction smelting furnace production, in particular to a device for crushing scales of a vacuum induction smelting furnace and application thereof, the device comprises a grinding roller and a grinding roller rotating shaft, the grinding roller rotating shaft is connected with the grinding roller, the roller rotating shaft is connected to the fixed platform through the height adjusting mechanism, and the height adjusting mechanism can be adjusted in a self-adaptive mode to change the distance between the roller and the cooling disc, and the fixed platform is fixed to the induction melting furnace. The grinding roller is fully contacted with the alloy flakes, so that the effect of fully crushing the flakes can be achieved, smaller-sized flakes are provided for the subsequent powder process, and the charging amount and the hydrogen absorption effect of hydrogen embrittlement treatment in the powder process are improved.

Inventors

• LI WEI
• SHAO MEIZHU
• SONG SHULIN
• CHEN HAIDONG
• WANG XUTAO
• HAO CHANGJUN

Assignees

• 南通正海磁材有限公司
• 烟台正海磁性材料股份有限公司

Dates

Publication Date

20260508

Application Date

20221025

Claims (10)

1. 1. A method for preparing an Nd-Fe-B permanent magnet by adopting a vacuum induction melting furnace with a flake breaking device is characterized by comprising the following steps: The vacuum induction smelting furnace with the flake breaking device comprises a furnace body, a cooling disc and the flake breaking device; the scale crushing device comprises a roller and a roller rotating shaft, the roller rotating shaft is connected to the roller, the roller rotating shaft is connected to a fixed platform through a height adjusting mechanism, the height adjusting mechanism can be used for adaptively adjusting the height so as to change the distance between the roller and a cooling disc, the roller in the scale crushing device is positioned at the top of the cooling disc, and the fixed platform is connected to a furnace body; The method comprises the following steps: s1, adding raw materials into a vacuum induction melting furnace for melting and casting to obtain alloy flakes; S2, placing alloy flakes on a cooling disc; s3, crushing alloy flakes on the cooling disc by using a plurality of plow-shaped devices and a flake crushing device to obtain fragments; s4, sequentially carrying out hydrogen crushing and air flow grinding on the fragments to obtain powder; S5, molding the powder in an orientation magnetic field, and sintering to obtain the Nd-Fe-B permanent magnet.
2. 2. The method of claim 1, wherein the height adjustment mechanism comprises a mounting vertical beam and a rotating shaft connecting arm, wherein the top end of the mounting vertical beam is connected with the fixed platform, the bottom end is rotatably connected with the rotating shaft connecting arm, and the end of the rotating shaft connecting arm away from the mounting vertical beam is connected with the rotating shaft of the grinding roller.
3. 3. The method of claim 2, wherein the mill roll shaft is connected to a shaft connection arm by a shaft clamp.
4. 4. The method of claim 2, wherein the shaft connecting arm is connected to the shaft clamp by a fixing member, and the roller shaft is clamped or sleeved to the shaft clamp.
5. 5. The method according to claim 2, wherein a mounting slot is provided at the connection position of the mounting vertical beam and the rotating shaft connecting arm, the top end of the rotating shaft connecting arm is embedded into the mounting slot, a self-locking nut passes through the mounting slot to fix the rotating shaft connecting arm, and the rotating shaft connecting arm can rotate with the self-locking nut as an axis to adaptively adjust the distance between the rotating shaft of the grinding roller and the fixed platform.
6. 6. The method according to any one of claims 1 to 5, wherein the roller shaft is inserted into the roller, and both ends of the roller shaft protrude from the roller, and the roller shaft is inserted into a lower portion of the roller.
7. 7. The method of claim 6, wherein the roller shaft is inserted into the roller at a position between one-fourth and one-half of the roller in a lateral center and a longitudinal direction of both ends of the roller.
8. 8. The method according to any one of claims 1 to 5, characterized in that the bottom of the grinding roller is in contact with the upper surface of the cooling disc of the vacuum induction melting furnace, that the grinding roller is provided with crushing teeth comprising toothed ring portions and spacer ring portions, that the spacer ring portions are arranged between adjacent toothed ring portions, that the outer periphery of the toothed ring portions is provided with crushing blades.
9. 9. The method of claim 8, wherein the crushing blade has a trapezoidal or triangular longitudinal cross section, and the blade has an end angle of 15-60 ° when triangular.
10. 10. The method according to any one of claims 1 to 5, wherein the smelting furnace further comprises a plurality of plow devices, the plurality of plow devices being located above the cooling disc and being movable up and down relative to the cooling disc.

Description

Flake crushing device of vacuum induction melting furnace and application thereof Technical Field The invention relates to the auxiliary field of vacuum induction smelting furnace production, in particular to a device for breaking scales by a vacuum induction smelting furnace and application thereof. Background The neodymium-iron-boron rare earth permanent magnet material has excellent magnetic property, is widely applied to the fields of medical nuclear magnetic resonance imaging, computer hard disk drive, sound equipment, mobile phones, household appliances, automobiles, wind power generation and the like, and has increasingly increased demand along with the rapid development of low-carbon, environment-friendly and economic and electronic technologies. The production process of the neodymium-iron-boron rare earth permanent magnet material comprises smelting, ingot casting, powder preparation and sintering, wherein the smelting is to melt various metals through heating, to become molten liquid and to be homogenized to form alloy liquid, the ingot casting is to cast the molten alloy liquid into a certain shape and size to form an alloy ingot with a certain microstructure, namely alloy flakes, the powder preparation is to crush the alloy flakes and perform air flow grinding treatment to form alloy powder, and the alloy powder is pressed into blanks and sintered to obtain the neodymium-iron-boron rare earth permanent magnet material (also called Nd-Fe-B permanent magnet). A large number of practices prove that the microstructure of the alloy ingot has important influence on the structure and performance of the finally obtained Nd-Fe-B permanent magnet, if dendritic alpha-Fe and isolated massive Nd-rich phases appear in the alloy ingot, the defects of different ingredients of powder produced in the early, middle and later stages, excessive residual powder, uneven powder particle size, irregular powder appearance and the like in the air stream grinding treatment process are caused, so that only a part of liquid phase sintering is caused in the product during sintering, the isolated massive Nd-rich phases are unevenly distributed along grain boundaries, the grain size is uneven, the magnetic performance of the d-Fe-B permanent magnet is reduced, the consistency is poor, and the qualification rate of the prepared Nd-Fe-B permanent magnet is low. In order to solve the problems, a vacuum induction melting furnace is widely used for producing alloy flakes to replace alloy ingots prepared by melting and ingot casting, and the microstructure of the alloy flakes meets the following requirements that alpha-Fe and massive Nd-rich phases do not appear in the alloy flakes of the vacuum induction melting furnace, the Nd-rich phases are uniformly distributed along a flaky grain boundary of an Nd 2Fe14 B phase, an amorphous area or an ultrafine (< 0.1 mu m) isometric crystal area does not exist, columnar crystals are arranged inside the alloy flakes of the vacuum induction melting furnace, and the alloy flakes are penetrating fine columnar crystals, so that the qualification rate of Nd-Fe-B permanent magnets can be effectively improved. In order to facilitate the hydrogen embrittlement crushing treatment of powder making in the production process of a vacuum induction melting furnace, the alloy flakes separated from the quenching roller are required to be crushed into a small-size structure in the smelting, pouring and cooling processes, a plurality of plow-shaped devices shown in fig. 1 are adopted to crush the alloy flakes, and the plow-shaped devices move up and down at a fixed speed to be matched with the rotation of a cooling disc to crush the alloy flakes. However, as the contact area between the crushing device and the alloy flake is smaller, the crushing effect is poorer, a large amount of alloy flakes are difficult to crush to the standard size, the hydrogen embrittlement crushing treatment in the powder process has the problems of lower furnace loading amount, poorer hydrogen absorption effect, lower powder process efficiency and the like. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides the flake crushing device of the vacuum induction smelting furnace, which is characterized in that the grinding roller is arranged behind the quenching roller of the smelting furnace, and is driven to rotate by the cooling disc, so that the grinding roller is fully contacted with alloy flakes (hereinafter called flakes) to achieve the effect of fully crushing the flakes, small-size flakes are provided for the subsequent powder making process, and the charging quantity and the hydrogen absorption effect of hydrogen embrittlement treatment in the powder making process are improved. The invention aims to provide a scale crushing device of a vacuum induction melting furnace, which comprises a grinding roller and a grinding roller rotating shaft, wherein the grinding roller rotating shaft