Useful wrinkle prefabrication method for improving internal high-pressure forming limit in pipe

Abstract

The invention discloses a useful wrinkle prefabrication method for improving the internal high-pressure forming limit in a pipe, and belongs to the technical field of pipe hydraulic forming. The useful wrinkle prefabrication method can solve the problems that control difficulty and mutual restriction of wrinkles exist in the useful wrinkle high-pressure forming high-expansion-rate pipe fittings made of low-plasticity materials. An induction heating device is used for locally heating a wrinkle-required position of a low-plasticity pipe blank, and after the local temperature of the pipe blank meets the requirement, bending and plastic instability occur in the pipe blank at the heated position under the action of axial material supplementation or under the combined action of internal pressureand axial material supplementation, thus forming the local wrinkles, and the forming continues in such manner until the preforming of all the wrinkles are completed. A useful wrinkle pipe blank is placed into an inner high-pressure forming die, and then pressurized and shaped until the prefabricated wrinkles are completely ironed, attached to dies and formed into final pipe fittings. According tothe useful wrinkle prefabrication method, the dependence on the die structure is avoided, materials are pre-gathered in the inner high-pressure forming areas through the useful wrinkle prefabricating, the limit expansion rate of the pipe fittings is larger after the wrinkles are ironed, and accordingly the distribution of wall thickness is more uniform.

Description

technical field [0001] The invention belongs to the technical field of pipe hydroforming, and in particular relates to a beneficial wrinkle prefabrication method for increasing the limit of high-pressure forming in pipes. Background technique [0002] Lightweight alloy pipes, such as aluminum alloys, magnesium alloys and even titanium alloys, due to their low plasticity at room temperature, are prone to wall thickness reduction or even instability and cracking under the action of bidirectional tensile stress during internal high pressure forming. For this reason, researchers at home and abroad have proposed a variety of methods to improve the formability of high-expansion high-pressure formed pipe fittings in light alloy pipes. Among them, beneficial wrinkle internal high pressure forming refers to the method of pre-accumulating and distributing material in the bulging zone by using the axial instability wrinkling behavior of the pipe, and then flattening it in the shaping s...

AI Technical Summary

Problems solved by technology

[0004] The present invention aims at the problems of difficulty in wrinkle control and mutual restriction existing in high-expansion rate pipe fittings with beneficial wrinkles in low-plastic materials, and provides a beneficial wrinkle prefabrication method for improving the limit of high-pressure forming in pipes

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