Large Thick-walled Hemispherical Head Forming Process Theory And Experimental Research

Heavy forgings, as important basic components in technological equipments and major projects, are widely used in nuclear power, hydropower, thermal power and transportation. Its manufacturing capacity and the level directly influence the related equipment-manufacturing capacity and the level. However, there is a huge gap between China and other countries. Some advanced products, like heavy forgings used for large-scaled hydropower, nuclear power, thermal power and metallurgy industry are far beyond the demand quality, which has became the bottleneck blocking the key project constructions and important technological equipments.Objecting the forming technology of the Hydroecium head on the Nuclear evaporator,this paper uses the research method combined with the finite element numerical simulation and the experimental verification,mainly reseaches the law of materials plastic deformation and the optimization of process parameters in the drawing and local hole flanging ,and analyzes the main factors effecting the drawing and hole flanging forming,finally we summarize the effecting law of each process parameters in the forming,and determine the process project eventually.the research contents and conclusions of this paper are as follows:1) drawing deformation: Through to the semifinished materials shape of strip and the mold revision, and unifies the mold gap the adjustment and so on the different plan, in the solution initial plan spherical surface partial wall thickness non-uniform and straight wall partial wall thickness and backs up the position not to conform to forging chart questions and so on requirement, enables the spherical surface partial wall thickness thinnest spot in to achieve the forging chart request under the premise, strives for the drawing shell cover forming the most superior effect, has determined the reasonable craft parameter2) hole flanging: based on the sheet drawing forming and following the requirements, hole flanging forms two joint pipe sections in the designated spot to the Semi-spherical head.considering the wall-thickness and maximam flanging height of joint pipe sections, we optimize the factors of pre-processing hole diameter and hole profile,improve the phenomenon of retract waist,and determine the reasonable process parameters.Based on the optimized project and adopting the 1:3 experiment method to verify,the gathered experimental data can show the consistency of experimental result and numerical simulation result,verify the feasibility of the process project,and complete the numerical simulation analysis and 1:3 simulation experiment.Through the numerical simulation and 1:3 experimentalsimulation, this paper analyzes the process parameters effecting the head wall-thickness and controlling size,get the wall-thickness distribution law and the main process parameters effecting the joint pipe sections shape and size,and complete the plate shape structure and the die design of the blank as well as the die design of the hole flanging process.This topic research work is to improve the science and accuracy of the production process to the large-scale forging, provides the theory basis for the same type product production, and establishes the foundation for the try production of the Hydroecium head on the Nuclear evaporator,thus reaches the purpose of improving the enterprise economic benefic and enhancing technical reserve.