Quick-change forming die for preparing large-diameter magnesium alloy pipes

Abstract

The invention discloses a quick-change type forming die for preparing a large-caliber magnesium alloy tubular product. The quick-change type forming die comprises a base with an inner hole. A materialcylinder right opposite to the inner hole is formed in the upper side of the base. A squeezing cavity for storing a blank is formed in the middle of the material cylinder. A squeezing rod for squeezing the blank and moving up and down along the squeezing cavity is arranged on the squeezing cavity. A heating device for heating the blank is arranged in the material cylinder. A female die at a holeopening of the inner hole is detachably connected with the bottom of the material cylinder. A squeezing pin comprises a flow guide rod, a forming piece and a guide rod which are sequentially in threaded connection from top to bottom, wherein a squeezing channel for performing continuous squeezing and cutting and pipe expanding and shaping on the blank is formed between the outer side face of the forming piece and the inner wall of the female die. A cooling device for cooling the formed blank is arranged on one side of the base, and the blank is rapidly cooled by the cooling device after dynamic crystallizing of magnesium alloy is completed through the squeezing channel to form the magnesium alloy tubular product when the blank is squeezed by the squeezing rod.

Description

technical field [0001] The invention relates to the technical field of forming thin-walled pipes, in particular to a quick-change forming die for preparing large-diameter magnesium alloy pipes. Background technique [0002] In industrial production, large plastic deformation technology (SPD) is widely used to prepare various profiles. The traditional light alloy plastic deformation process includes multiple stages such as ingot preparation, ingot treatment, billet heating, and thermoplastic deformation. The processing of magnesium alloy pipes is mainly through the extrusion molding of quick-change molding dies. [0003] For the preparation of ultra-fine-grained alloy (light alloy) pipes, especially thin-walled and high-precision light alloy pipes, at present, extrusion is mainly used for forming. During the extrusion process, the metal is subjected to three-dimensional stress to make the forming The pipe has excellent performance. [0004] The traditional extrusion produc...

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Problems solved by technology

[0004] The traditional extrusion production process is generally forward extrusion, but during forward extrusion, the friction between the billet and the extrusion cylinder is relatively large, the metal flow is uneven, and the forward extrusion will form a band along the extrusion direction of the pipe. Organization and strong basal texture, resulting in anisotropy of the pipe, thereby reducing the mechanical properties of the formed pipe

These formed basal textures are also easy to cause defects such as shrinkage cavities and porosity in the light alloy casting structure in the secondary processing of thin tubes, which makes the processing accuracy of tubes, especially thin tubes, worse.

Moreover, the transverse cross-sectional structure of light alloy pipes after traditional forward extrusion is equiaxed grains, and the longitudinal cross-sectional structure after extrusion becomes elongated grains, which has a great influence on its mechanical properties

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