A kind of positive and negative extrusion forming die and forming method of curved generatrix shell

Abstract

The invention discloses a forward and reverse extrusion forming die and forming method of a curved generatrix type shell. By extruding the bottom of the forming cavity of the concave die, the forming space is positively extruded. When the extrusion punch moves downward, the lower end of the extrusion punch is extruded. The billet at the center is dominated by positive flow, and the positive extrusion forming space is filled preferentially to promote the positive flow of the material and increase the strain of the material in the dead zone; when the extrusion punch continues to move downward, the positive extrusion forming space is filled. , the blank at the lower end of the extrusion punch is dominated by reverse flow and fills the forming cavity. An overflow groove is set on the upper part of the reverse extrusion forming cavity, and the extrusion punch is pressed down into the overflow groove, and the blank is closed and extruded in the forming cavity, and the blank flows forward and reverse at the same time, which promotes the positive flow of the mouth material. Flow, increase the strain of the material in the rigid translation zone, so as to achieve uniform material strain in different parts of the shell, and solve the problems of uneven deformation and large differences in mechanical properties between different parts and directions after the existing curved generatrix shell is formed. .

Description

technical field [0001] The invention belongs to the technical field of forming and processing, and in particular relates to a positive and negative extrusion forming die and a forming method of a curved generatrix type shell. Background technique [0002] Extrusion forming is a forging forming process. The blank is subjected to three-dimensional compressive stress, and its circumferential mechanical properties are uniform. It is suitable for forming difficult-to-deform metal materials. During the extrusion process, the billet and the mold move relative to each other, and the material flows out in the same direction as the extrusion axis, which is called positive extrusion; [0003] It is recorded in the patent application number CN201710544672.2 that when the grid changes in each stage of traditional forward extrusion, the grid change inside the billet is divided into three areas: Zone I is the metal dead zone, which is close to the end face of the punch, Conical. The size...

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Problems solved by technology

[0008] The technical problem to be solved by the present invention is to provide a positive and negative extrusion forming die and forming method for curved generatrix shells, so as to solve the problems of uneven deformation and large differences in mechanical properties of existing curved generatrix shells after forming

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