Forward and backward extrusion forming die and method for curved generatrix type shell

Abstract

The invention discloses a forward and backward extrusion forming die and method for a curved generatrix type shell. Forward extrusion forming space is formed in the bottom of an extrusion female die forming cavity, when an extrusion male die moves downwards, a blank at the lower end of the extrusion male die mainly flows in the forward direction, the forward extrusion forming space is preferentially filled, forward flowing of materials is promoted, and the dependent variable of the materials in a dead area is increased; and when the extrusion male die continues to move downwards, after the forward extrusion forming space is filled, the blank at the lower end of the extrusion male die mainly flows reversely and fills the forming cavity. An overflow groove is formed in the upper portion of abackward extrusion forming cavity, the extrusion male die is pressed downwards into the overflow groove, the blank is extruded in the forming cavity in a closed mode, the blank flows forwards and backwards at the same time, forward flowing of the materials at an opening is promoted, the dependent variable of the materials in a rigid translation area is increased, and therefore uniform material strain of different parts of the shell is achieved, the problems that after an existing curved generatrix type shell is formed, deformation is uneven, and the difference of mechanical properties of different parts and in different directions is large are solved.

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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