AP1000Nuclear Power Main Pipe Bending Technology Research

Nuclear power plant main tube is large thick pipet that connected to the pressurevessel in reactor and the steam generator in a nuclear island, is the "main artery" ofnuclear steam supply system outputting reactor heat, is one of the key parts of the nuclearlevel of nuclear power plants. The main channel of APl000third-generation nuclear powertechnology require the use of the the overall forming method of manufacturing, andrequire that nozzles is one piece with the main tube. Pipe bending process is a bigdifficulty, there is no off-the-shelf manufacturing technology abroad. And they developedwith China in the same period. Therefore, to study and master the whole bendingtechnology of the main channel of nuclear power and to achieve localization are theproblems which are need to be solved urgently. In this paper, against the main pipebending process at room temperature, using the straight pipe tube through a theoreticalderivation, numerical simulation and1:10straight tube bending experiments, the rules thatthe reduction, mode radius of curvature, friction coefficient, eccentric tube affect formingquality are obtatined.In this article, the forming of the main tube use bending process bending. Accordingto local plastic deformation mechanism, the formula for critical die spacing is obtained.The formula for calculating the stroke was derived by an analysis of the geometricposition change of bending tube forming. On this basis, the numerical simulation forstraight pipe press-bending process was performed via MSC.Marc finite element analysis.The stress-strain state of the tube, forming quality and the reasons of quality out of thestandards are obtained.This article by numerical simulation of straight pipe tube forming. the rules that theprocess parameters and the design parameters of eccentric pipe affect forming quality areobtatined.Analysis: bending radius and bending angle respectively show the trend ofincreases and decreases as the coefficient of friction increases; getting the curvature radiusof the upper die and the springback compensation of upper die; at the same time definingthe design parameters of the eccentric pipe.A bending test mold, a straight tube and the eccentric pipe are produced according to the proportion of1:10. Straight-tube tube and eccentric tube bending experiments areaccomplished by bending test mold. The experimental results show that: the rules thatmode stroke, curvature radius of upper die and the design of the pipe impact pipe formingquality are consistent with the calculation results; forming quality of pipe that was bendedby eccentric tube met the standards. Through the whole research: getting reference valuesof the process parameters and the design parameters of eccentric pipe.