Continuous gradual expanding and rounding device and method for thick-wall metal longitudinal welded tube

Abstract

The invention belongs to the technical field of expanding and rounding of longitudinal welded pipes, and particularly relates to a continuous gradual expanding and rounding device and method for a thick-wall metal longitudinal welded tube. A continuous gradual expanding and rounding device for a thick-wall metal longitudinal welded tube comprises a left base and a right base, wherein a left rack and a right rack are arranged at the tops of the left base and the right base respectively, the left rack is hinged to the corresponding base, and bearing seats corresponding to each other are installed on the upper portion of the left rack and the upper portion of the right rack; and a variable-size core shaft is arranged in the two bearing seats. According to diameter expansion, the variable-size core shaft is sleeved with a tube, the tube makes contact with a working roller in the working process, the working roller rotates to drive the tube body to rotate, roundness treatment is conducted on the tube under the pressure action of the variable-size core shaft and the working roller, the variable-size core shaft is gradually opened in the process, and the diameter of the tube is expanded while the tube is expanded. The internal and external stress difference of the tube is eliminated, the tube Bauschinger effect is effectively reduced, and the internal residual stress of the tube is effectively reduced.

Description

technical field [0001] The invention belongs to the technical field of diameter expansion and rounding of straight seam welded pipes, and in particular relates to a continuous and gradual diameter expansion and rounding device and method for thick-walled metal straight seam welded pipes. Background technique [0002] Large-diameter thick-walled straight seam welded pipe, because of the use of JCOE forming technology, its end face shape is a nearly circular polygon, and the mechanical properties of the inner and outer walls of the pipe are quite different, so it will affect the application in petrochemical, offshore engineering, oil and gas transmission, infrastructure projects, etc. Widely used in the industry. At present, the general method is to use a mechanical expanding machine to gradually expand the diameter of the submerged arc welded pipe radially through the expanding tool to ensure the roundness, straightness and dimensional accuracy, but because the cross section ...

AI Technical Summary

Problems solved by technology

At present, the general method is to use a mechanical expanding machine to gradually expand the diameter of the submerged arc welded pipe radially through the expanding tool to ensure the roundness, straightness and dimensional accuracy, but because the cross section of the expanding head is circular , so the expansion is a uniform plastic deformation. Although part of the residual stress can be eliminated, the rounding effect is still not ideal, and the mechanical expansion machine requires a large force when processing thick-walled pipes, resulting in a large equipment structure. High energy consumption and high investment

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