Novel female die structure for necking pipe fittings

Abstract

The invention provides a novel female die structure for necking pipe fittings, which can prevent the bulging and wrinkling of the pipe fittings and the thinning of pipe walls due to extrusion in the necking process of the pipe fittings effectively, overcome the defect that the necked pipe fittings are bent due to the materials of welding lines of high-frequency welding pipes effectively when the pipe fittings are used as the high-frequency welding pipes, solve the problem that rear ends of the pipe fittings are bulged due to relatively long necking lengths of the pipe fittings and large friction extrusion force between necking sections and a female die cavity and ensure the necking accuracy of the welding pipe fittings. The female die structure comprises a necked female die body and is characterized in that: a hard alloy sleeve is inlaid at the inlet end of an inner hole of the necked female die body and comprises an inlet end pre-reducing section and a reducing section which are in arc transition connection with each other.

Description

technical field [0001] The invention relates to the technical field of pipe fitting processing, in particular to a novel die structure for pipe shrinking processing. Background technique [0002] The general shrinking processing of pipe fittings is to directly squeeze the pipe fittings through the shrinking die to achieve the purpose of shrinking. Each point on the die arc extrudes the material of the pipe fittings. The pipe fittings are easy to bulge or wrinkle during the extrusion process, and it is easy to cause the material to become thinner and affect the quality of the pipe fittings. Therefore, the pipe fittings usually need to be shaped after shrinking processing. Its processing accuracy is low and processing efficiency is low; when the pipe fittings are high-frequency welded pipes, because the material in the weld area is in a quenched state, the extrusion elongation of the material in the quenched area is greatly different from that in other areas during the shrinka...

AI Technical Summary

Problems solved by technology

[0002] The general shrinking processing of pipe fittings is to directly squeeze the pipe fittings through the shrinking die to achieve the purpose of shrinking. Each point on the die arc extrudes the material of the pipe fittings. The pipe fittings are easy to bulge or wrinkle during the extrusion process, and it is easy to cause the material to become thinner and affect the quality of the pipe fittings. Therefore, the pipe fittings usually need to be shaped after shrinking processing. Its processing accuracy is low and processing efficiency is low; when the pipe fittings are high-frequency welded pipes, because the material in the weld area is in a quenched state, the extrusion elongation of the material in the quenched area is greatly different from that in other areas during the shrinkage deformation process. When the material elongation in other areas is greater than the elongation of the material in the quenched state, the reduced diameter pipe will bend in a circular arc toward the weld, causing a large error in the concentricity between the reduced diameter and the unreduced area of ​​the pipe, and in The arc shape error at the weld is not easy to shape, and its processing accuracy is poor and the processing efficiency is low; in addition, when the pipe fittings have a long shrinkage length, the pipe fittings with a reduced diameter will have a large impact on the cavity wall of the shrinking concave model during the shrinking process. frictional extrusion force, when the frictional extrusion force is greater than the yield strength of the pipe material, the rear end is prone to bulging deformation before entering the cavity of the concave mold, which deteriorates the working state of diameter reduction

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