Combination bending upper die structure for nuclear power main pipe forming

Abstract

The invention relates to a combined bending upper-die structure for forming a nuclear power main pipe. Two bending die sections are fixedly connected through tightening screws and combined into a complete upper die, two fixing plates are fixed to bending modules through screws, the fixing plates enable the combined bending modules to be fixed to an upper die plate through bolts, and the complete upper die is assembled. Before a pipe blank is bent, through a matching plane of the lower end of the upper die and a lower die, centring and alignment of a die are conducted; in a forming process, the forming working surface of the split die can not only guarantee forming of a corresponding arc surface of a pipe fitting but also control distortion of the section shape of the bending portion of the pipe fitting, and forming precision of the pipe fitting is improved; after bending forming is finished, the bolts are disassembled firstly so as to separate the bending modules from the upper die plate, then the tightening screws are disassembled so as to separate the two die sections, and disassembly of the upper die is completed after the nuclear power main pipe is bent. The combined bending upper-die structure is simple, easy and convenient to assemble and disassemble, safe, reliable, and capable of forming the pipe fitting with a complex shape, guarantees forming quality of the bending portion as much as possible, and prevents the die from having interference in a pipe joint nozzle on the pipe fitting during die release.

Description

technical field [0001] The invention relates to a pressing die for bending and forming pipes, in particular to a combined bending upper die structure for a nuclear power main pipe with a spout. Background technique [0002] At present, the AP1000 third-generation nuclear power technology introduced by the US Westinghouse Company in my country has increased its design life to 60 years, so the safety performance indicators of nuclear power plants have also been greatly improved. According to the design requirements, the nuclear power main pipeline is manufactured by integral forging method, and the nozzle and the main pipeline are required to be integrally forged. However, the two overall forged nozzles with a relative angle of 45° on the main pipe will inevitably lead to complicated shapes of the pipe fittings. When performing cold bending, problems such as difficulty in aligning the upper and lower dies with the existing structure of the upper die, difficulty in disassembli...

AI Technical Summary

Problems solved by technology

However, two overall forged nozzles with a relative angle of 45° on the main pipe will inevitably lead to complicated shapes of pipe fittings

When performing cold bending, problems such as difficulty in aligning the upper and lower dies with the existing structure of the upper die, difficulty in disassembling the upper die after bending, and distortion of the cross-sectional shape of the bent part of the tube billet will occur. Tubes posed great difficulties

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