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Large diameter straight seam welded pipe cold expansion

Date:2018-03-06    View:479      Tag:Large diameter straight seam welded pipe cold expansion
Large diameter straight seam welded pipe cold expansion is the use of hydraulic or mechanical means, the steel pipe from the steel wall radially outward expansion of the pressure forming process. Compared with the mechanical hydraulic method, the equipment is simple, high efficiency and high precision machining conditions more precise use of steel, emptying large diameter straight seam pipe in the reservoir do not need to use, and now the world's most advanced large diameter straight seam pipe using an expansion process, the process is as follows:


Mechanical bulging is the use of sub-part of the expanded diameter of the expansion of the radial expansion of the longitudinal tube-level step by step, so that the entire length of the pipe to achieve plastic deformation process. It is divided into five stages.
1, a round of the initial stage. The sections are opened until all the sections are exposed to the tube wall, at which time the step lengths in the range of each tube radius are approximately the same in range and the steel is initially rounded.
2, the nominal stage diameter. The Anterior section reduces the speed of movement from the starting position until the desired position is reached, which is the quality requirement for the circumferential position within the finished tube.
3, rebound compensation stage. Segment 2 is at a further slow speed at the beginning until it reaches the desired position, which is the circumferential position of the pipe before the elastic recovery is required during the design.
4, pressure stability level. Segmented before playing complex inner tube position to maintain a certain period of time unchanged, which is stable phase packaging equipment and to expand the process requirements.
5, uninstall the return stage. The starting position of the circumferential section is quickly retracted from the front of the inner tube before reaching the initial diameter of the inner tube, which is the minimum diameter required by the expansion process.

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