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Preparation method for cold crucible for directionally solidifying neodymium iron boron cast ingot

A directional solidification, neodymium iron boron technology, applied in self-solidification method, crucible furnace, chemical instruments and methods, etc., can solve the problem of low magnetic performance, achieve the effect of improving performance and reducing melt pollution

Active Publication Date: 2013-04-03
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] In view of the problem of low magnetic properties of existing NdFeB permanent magnet materials, and the problem that the market has put forward higher requirements for the magnetic energy product and coercive force of NdFeB permanent magnet materials, the present invention provides a directionally solidified neodymium The cold crucible preparation method of iron boron ingot can effectively improve the performance of NdFeB permanent magnet material

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  • Preparation method for cold crucible for directionally solidifying neodymium iron boron cast ingot
  • Preparation method for cold crucible for directionally solidifying neodymium iron boron cast ingot
  • Preparation method for cold crucible for directionally solidifying neodymium iron boron cast ingot

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Embodiment 1

[0038] The method of the present invention is completed by electromagnetic cold crucible constrained forming and directional solidification equipment, which mainly includes the following components: (1) electromagnetic field melting system; (2) motion system; (3) vacuum system; (4) cooling system; (5) Control system. Among them, the electromagnetic field melting system mainly includes water-cooled copper crucible and induction coil. The cooling system mainly includes the water cooling of the crucible and the furnace body and the cooling of the NdFeB alloy by the Ga-In coolant during the solidification process. Together with the motion system, they constitute the entire equipment. The main part is the forming crystallization part; the real control system is composed of diffusion pump, vacuum pump and vacuum chamber; the control system is responsible for precise control of parameters such as heating power, vacuum degree, and moving speed of upper and lower rods during the directi...

Embodiment 2

[0068] The difference between this embodiment and Embodiment 1 is that the water-cooled copper crucible used in the method described in this embodiment is provided with a trapezoidal boss 13 on its inner wall, such as Figure 14As shown, the trapezoidal boss is placed in the induction area of ​​the induction coil, the trapezoidal boss has an upper inclined surface and a lower inclined surface, and the included angles between the upper inclined surface, the lower inclined surface and the horizontal plane are all 45° Of course, it can also be set to 30 degrees, 45 degrees, 50 degrees or 60 degrees according to needs, and the degrees of inclination of the upper and lower inclined surfaces can be equal or unequal. The upper inclined surface will generate an upward thrust, increase the quality of the melting zone, provide a large volume of melt, reduce the disturbance to the lower liquid hump, and improve the surface quality of the ingot.

[0069] The downward sloping surface will ...

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Abstract

The invention provides a preparation method for a cold crucible for directionally solidifying a neodymium iron boron cast ingot to solve the problems that the conventional neodymium iron boron permanent magnet material has low magnetic performance and the market has higher requirement on the magnetic energy product and the coercive force of the neodymium iron boron permanent magnet material. According to the preparation method, a crystallizer accommodating a coolant material is placed under a water-cooling copper crucible; a backing material is fixed at the upper end of a lower drawing rod arranged in the crystallizer; the heating power of an electromagnetic induction coil is 45 to 50 kW; and the drawing speed of the lower drawing rod is 0.5 to 1.2 mm / min. According to a cold crucible directional solidification technology, soft contact between a melt and the crucible is realized through an electromagnetic thrust, so that melt pollution in the casting process of the neodymium iron boron can be effectively reduced and the performance of the neodymium iron boron permanent material can be improved.

Description

technical field [0001] The invention relates to a method for directionally solidifying NdFeB alloy ingots. Background technique [0002] Since NdFeB permanent magnet alloy came out in 1983, due to its high performance and low price, it has played a role in promoting the development of biomedical equipment and new energy vehicles. The industry of NdFeB has developed rapidly and has been widely used It is used in high-tech fields such as information, medical treatment and energy saving. Although the domestic NdFeB industry started late, due to my country's abundant rare earth resource reserves and strong market demand, it has developed very rapidly, and its output has been increasing year by year. At present, my country has become an important exporter of NdFeB permanent magnet alloy materials, and its total output ranks first in the world. However, the development of my country's NdFeB permanent magnet material industry still faces huge obstacles. On the one hand, because ...

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Application Information

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IPC IPC(8): B22D23/06C30B11/00B22D11/00B22D27/04F27B14/06F27B14/10
Inventor 丁宏升冯魁王永喆
Owner HARBIN INST OF TECH