Metal pipe section roundness correction method and correction die

Abstract

The invention relates to a metal pipe section roundness correction method and a correction die. The correction method comprises the steps of forcing a pipe to be corrected to pass through a convex polygonal die in a drawing manner, and enabling the cross section of the pipe to be locally bent and deformed in order to adapt to a polygon, so that the roundness of the pipe is improved. The correction die comprises a die body and at least three movable die sections, wherein the die sections are provided with working faces; the working faces of the die sections are arranged around the center of the die and form a convex polygon; the distance from the corner of the polygon to the center of the die is larger than the radius of the pipe; and the radial distance from the die sections to the center of the die is adjustable. According to the correction method and the correction die provided by the invention, the roundness of the pipe can be improved under the condition that the diameter, the wall thickness nominal size and the performance of the metal pipe are not changed.

Description

technical field [0001] The invention belongs to the field of correction of metal pipes, and in particular relates to a correction method and a correction mold for the roundness of the cross section of metal pipes. Background technique [0002] Metal pipes are indispensable and important materials in the fields of national economy and national defense and military industry. When the pipe is used, it needs to be assembled and connected with other equipment or components such as pipe joints. In most cases, there are certain requirements for the dimensional accuracy of the pipe, especially the roundness of the section. In individual assembly cases, the application has a high requirement for the roundness of the section. [0003] Metal pipes are generally formed by drawing, rolling and other methods. On the one hand, the dimensional accuracy that can be achieved in the conventional processing process, including the roundness of the section, is limited, which may not meet the req...

AI Technical Summary

Problems solved by technology

Correction by drawing requires drawing of the "head", which increases the process and waste of the pipe head, and the accuracy that can be achieved by drawing correction is limited; the correction by rolling method takes more time for the process. Long, the process of rolling through the mandrel may also scratch the inner surface of the pipe

Moreover, the above two correction methods may cause the following problems: First, although the deformation is small, the size of the pipe, such as the wall thickness and diameter, may be changed, which may cause the size of some products that were originally qualified to exceed Second, it is necessary to add a cleaning process to remove the lubricating grease attached to the pipe due to correction; Third, if the correction process is not well controlled, there may be a possibility of performance change or size out of tolerance

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