Secondary torsion extrusion device and method for variable cross-section cavity with fine grain

Abstract

A secondary torsion extrusion device and method for refining crystal grains with a variable cross-section cavity, including: a punch part, a transmission mechanism, a power mechanism and a die part, wherein: the punch part cooperates with the die part, and the power mechanism It is connected with the transmission mechanism; the punch part includes the upper template and the upper mold, the concave mold part includes the upper cylinder, the upper plate and the main mold, the upper template is set on the upper mold, the upper mold is matched with the upper cylinder and the working state is in the hydraulic press Under the action of the slider, it enters the upper cylinder and the main mold. The upper cylinder is set on the upper plate, the main mold is set under the upper plate and connected with the upper cylinder, and the upper mold enters the upper cylinder when it is working. In the present invention, by changing the cross-sectional shape of the inner cavity of the rotating mold, the variable-section cavity mold is rotated at the same time of extrusion, and the material has both extrusion deformation and shear deformation caused by the rotation of the mold, thereby realizing severe plastic deformation and high forming force. Small, high deformation efficiency, can achieve good grain refinement effect.

Description

technical field [0001] The invention relates to a technology in the field of plastic processing for preparing ultra-fine-grained material rods, in particular to a secondary torsion extrusion device and method for a variable-section cavity with fine grains. Background technique [0002] Materials with ultrafine grains not only have good physical and mechanical properties, but can even achieve superplasticity under certain temperature and strain rate conditions when the grain size is less than 10 μm. The superplastic flow deformation resistance of the material is small, the fluidity and filling are excellent, and a large deformation can be obtained. An important condition for materials to be superplastic is to have ultra-fine grains, and a series of ultra-fine-grained materials with superior performance can be obtained by using large plastic deformation technology. [0003] Torsional extrusion is also a large plastic deformation process, but although the material grains produ...

AI Technical Summary

Problems solved by technology

[0003] Torsional extrusion is also a large plastic deformation process, but although the material grains produced by this process are refined, because the shear deformation is concentrated at the edge, there are differences in the size of the edge and core grains. have an adverse effect on the improvement of the performance of the material

In addition, the shear deformation of the material is mainly realized by the friction between the mold and the material. When the mold rotates at a high speed, there will be slippage and the torsion effect cannot be reflected.

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