Expansion pipe necking method

Abstract

The invention provides an expansion pipe necking method. A workpiece is hit by a die to form an inwards overturned and necked expansion pipe, the workpiece is heated, thereby being softened, and forceof each time of hitting is smaller than 100 kilogram force. The end of the expansion pipe is heated and softened and then is hit by the die, when hitting force is larger than 100 kilogram force, theexpansion pipe is liable to be twisted, when force is too small, machining efficiency of an inner necked opening of the expansion pipe is too low, meanwhile the second time of plastic deformation canbe conducted on the expansion pipe, the density of the end of the expansion pipe can be improved, connection strength between the expansion pipe and the inner necked opening and structural strength ofthe inner necked opening are improved effectively, connection strength of the expansion pipe and an outer connector can be improved conveniently, the expansion pipe is rotated while the inner neckedopening is machined, the thickening uniformity of the inner necked opening can be improved conveniently, attractiveness of the end of the inner necked opening of the expansion pipe is achieved conveniently, and machining quality can be improved conveniently.

Description

technical field [0001] The invention relates to the technical field of necking processing, in particular to a necking method of an expansion tube. Background technique [0002] Necked workpieces are widely used in daily life. With the advancement and development of science and technology, the requirements for the application and technology of various technologies are getting higher and higher. Necked workpieces are used more and more in fracturing devices. Generally, The necking forming method of the pressure vessel head is spinning. The spinning forming is easy to cause the roundness of the necking to be low (that is, elliptical), which brings difficulties to the later assembly of the pressure vessel. [0003] For example, patent CN200710185660.1 is a method of necking process commonly used to manufacture pressure vessels at present. After the double-end screw compression mouth is processed and formed, quenching and tempering are carried out for heat preservation. The proce...

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Problems solved by technology

[0007] However, in the process of processing pipes or workpieces in this method, when the end of the workpiece is processed for inner necking, the thickness of the inner necking is uneven, or the workpiece is twisted due to excessive extrusion force, which affects the processing quality. The processed product has insufficient structural strength and is prone to breakage, which in turn affects the connection and sealing effect between the workpiece and the external connector

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