Method for driving molten metal to flow three-dimensionally and periodically based on permanent spiral magnetic field

Abstract

The invention relates to a method for driving the molten metal to flow three-dimensionally and periodically based on a permanent spiral magnetic field and belongs to the technical field of metallurgical industry. A spiral magnetic field body is manufactured and composed of a plurality of permanent magnet units which are coaxially mounted and are rings, each of the permanent magnet units is composed of a plurality of permanent magnets and a support frame, the plurality of the permanent magnets are evenly embedded in the support frames, magnetization directions of adjacent permanent magnets are opposite, the permanent magnets of adjacent permanent magnet units are staggered at a certain horizontal angle beta successively along an anticlockwise or a clockwise direction, and a rise angle of a composed spiral magnetic field is alpha, so that the molten metal can be placed in a cavity of the spiral magnetic field, the spiral magnetic field rotates at a certain angular speed, rotation directions change alternatively at a certain period, and the molten metal is driven to flow three-dimensionally and periodically. According to the method, various defects in molten metal solidification can be reduced effectively, and the method is applicable in improving the metal solidification process.

Description

technical field [0001] The invention relates to a method for driving a three-dimensional periodic flow of a metal melt based on a permanent helical magnetic field, and belongs to the technical field of the metallurgical industry. Background technique [0002] Using electromagnetic methods to drive and control the flow of molten metal is an important research direction of electromagnetic metallurgy, such as electromagnetic stirring, electromagnetic braking and other technologies. [0003] At present, the electromagnetic metallurgical process can be divided into traveling wave magnetic field and rotating magnetic field according to the form of magnetic field movement. The above two forms of magnetic field movement can be realized by using permanent magnets and multi-phase alternating current coils. Due to the continuous improvement of the magnetic material performance of rare earth permanent magnet materials, it is another possibility to provide a moving magnetic field by usi...

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Problems solved by technology

Generally speaking, due to the application of traveling wave magnetic field, rotating magnetic field or helical magnetic field, the movement form of electromagnetic force acting on the solidification front of the metal is fixed, and the melt precipitation process will proceed in a fixed mode, so that the precipitation process of the melt at the solidification front will change over time. The change is very small, so the application of a magnetic field not only cannot improve the concentration segregation, but also has a tendency to increase the concentration segregation

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