Composite electromagnetic stirring process of preparing semi-solid metal slurry continuously

Abstract

The present invention relates to semi-solid material preparing technology, and is composite electromagnetic stirring process of preparing semi-solid metal slurry continuously. Smelted overheat metal liquid is first poured into one preheated pouring basket continuously and the metal liquid inside the pouring basket is stirred electromagnetically for homogeneous cooling to temperature near the liquid phase line. The metal liquid is then led out of the pouring basket through duct strongly stirred electromagnetically and cooled to obtain equiaxial fined homogeneous semi-solid metal slurry; and the metal liquid is finally led into one heat retainer. The slurry after heat retaining treatment may be further formed rheologically or thixotropically. The present invention has the advantages of advanced technological process, simple apparatus, easy control, high practicability, low slurry cost, great output and high product quality.

Description

technical field [0001] The invention belongs to the technical field of semi-solid metal processing, and in particular relates to a method for continuously preparing semi-solid metal slurry by applying compound electromagnetic stirring. Background technique [0002] The concept of metal semi-solid processing was first proposed by American scientists in the 1970s. The basic principle of this method is to apply vigorous stirring during the solidification of liquid metal, and break the generated dendritic primary crystals to form near-spherical primary crystals and The alloy slurry with the characteristics of non-dendritic structure composed of the residual liquid phase, this slurry still has good fluidity under the action of force even when the solid phase fraction is large, and can be directly transported to the forming equipment. Rolling, die-casting, extrusion, die forging and other conventional processes for processing and forming. This method combines the characteristics ...

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Problems solved by technology

At present, the technology of preparing semi-solid processing billets by electromagnetic stirring method has several patents at home and abroad, but their common characteristics are: low efficiency, large power consumption, complex equipment structure, and relatively high cost of semi-solid slurry and billets. High, so that the industrial application of semi-solid slurry or billet prepared by electromagnetic stirring method is slow, and the advantages of applying electromagnetic field have not been fully reflected

The deficiencies of the existing electromagnetic stirring method for preparing semi-solid slurry and billet technology are mainly manifested in: 1) electromagnetic stirring is applied outside the pulping chamber, and due to the large volume of the pulping chamber, it is necessary to require a large electromagnetic stirring power, resulting in electromagnetic equipment Large size, increased energy consumption, slow transition from dendritic to non-dendritic, coarse grains, long time and low efficiency for preparing semi-solid slurry; 2) When the volume of the pulping chamber is large, there is the problem of uneven distribution of the stirring magnetic field, which makes The molten metal at the edge and center of the pulping chamber is not stirred evenly, and early coagulation at the edge is prone to occur; 3) Since the diameter of the pulping chamber and the diversion pipe are similar, the slurry flow only depends on gravity, which will cause the slurry flow to be discontinuous ; When the solid phase fraction of the slurry is high, the thixotropy of the semi-solid slurry cannot be fully exerted due to the lack of force that causes the semi-solid slurry to repeatedly shear, and the viscosity is relatively high, making it difficult to continuously transport the slurry 4) The process of stably preparing semi-solid slurry with ideal solid phase fraction is not yet mature, and the slurry cannot be directly used for rheological forming

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