Process method for improving high pressure forming limit in tube

Abstract

The invention relates to the field of machine manufacturing, in particular to a process method for improving high pressure forming limit in a tube. The invention adopts the technical scheme that the process method comprises the following steps of: firstly providing axial supplementation at the end part of a tube billet under relatively lower pressure, ensuring that the tube billet is smoothly conveyed to a bulging region to form tiny beneficial creases, and then stopping the axial supplementation; then raising pressure, re-shaping the tube billet in the bulging region until the tiny beneficial creases disappear, and then reducing the pressure; repeating the processes until a part contact die is formed; removing inner pressure, withdrawing a punch at the end part until the punch and a die cavity are completely separated, and opening the die, and taking out the part from the die. According to the method, the defects that unstability and corrugation are easily generated at the end part of the tube billet due to excessive friction force under the condition of performing axial supplementation and inner pressure reforming at the same time and the bulging region is easily broken because of insufficient supplementation and the beneficial creases can not be repeatedly utilized are avoided, therefore, the forming limit of the tube can be greatly improved, the steps of performing and thermal treatment are reduced, meanwhile, the abrasion of the die cavity is greatly reduced, and the die life is prolonged.

Description

Technical field: [0001] The invention relates to the field of mechanical manufacturing, in particular to a process method for increasing the limit of high-pressure forming in pipes. Background technique: [0002] In the past, a linear loading path was adopted in internal high pressure forming, and the characteristic of the loading path is that the amount of axial feeding and internal pressure increase monotonically at the same time, that is, the internal pressure continues to rise as the axial feeding proceeds. This loading method has a wide forming window when forming small expansion parts, and does not require high equipment control accuracy. However, when forming large expansion parts or complex cross-sectional shapes, the forming window is very narrow and the process is very difficult. The traditional method to improve the performance of high pressure forming at room temperature is to improve or restore the forming ability of the tube blank by precisely controlling...

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Problems solved by technology

[0003] The purpose of the present invention is to aim at the above-mentioned defects existing in the prior art, to provide a process method for increasing the limit of internal high-pressure forming of pipes, and to solve the significant difficulty in axial feeding in current high-expansion parts or low-plastic materials in internal high-pressure forming, Prone to problems such as destabilization, wrinkling and cracking

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