Differential pressure expansion method of pipe

Abstract

The invention relates to a differential pressure forming method specially aiming at improving the formability of a pipe. In order to solve the problem that a material far away from a material supplementary position is easy to crack under the action of a bi-directional tensile stress during a pipe high-pressure forming process, the invention provides the method characterized by applying a certain liquid pressure on the outer part of a part on the basis of an original process so as to improve the formability of the pipe. The preparation method mainly comprises the steps of manufacturing a special female mold for differential pressure expansion; calculating a wall thickness reduction parameter and an external pressure value; carrying out differential pressure expansion; and unloading and obtaining a final part. After forming, the inner pressure of the pipe is unloaded, and the mold is opened to obtain the final hollow part with large deformation and relatively uniform wall thickness. According to the method provided by the invention, when the forming processing is carried out on the pipe, an internal and external pressure difference of a pipe blank is controlled to improve a stress state during pipe blank forming, so that the sufficiency in forming is realized, the occurrence of the phenomena such as expansion cracks and folds during a forming process is reduced, and the problem that the pipe blank is cracked or excessively thinned during the forming process is finally alleviated to a certain degree.

Description

technical field [0001] The invention belongs to the technical field of metal hollow parts manufacturing and relates to a differential pressure forming method specially aimed at improving the formability of pipes. Background technique [0002] Hollow structural parts are widely used in automobiles, machinery, ships and aerospace industries, and are also an indispensable part of various equipment pipeline connections. With the development of industry, the lightweight, toughness and low-consumption and high-efficiency precision forming technology of products has become the development trend of modern manufacturing technology. The use of hollow structure can not only reduce weight and save materials, but also make full use of the strength and rigidity of materials. It is against this background that tube bulging is developed as an advanced manufacturing technology for manufacturing hollow light-body components. It realizes the "substituting space for solid" in the structure of ...

AI Technical Summary

Problems solved by technology

[0007] The purpose of this invention is to solve the problem that the material at the position far away from the feeding position is easy to crack under the action of bidirectional tensile stress in the high pressure forming process of the pipe, and propose a method of applying a certain liquid pressure on the outside of the part on the basis of the original technology. Method to improve the formability of pipes

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