Research On Shaped Process And Microstructure Control Of Large Rpv Head On Top With Unequal Wall Thickness

With the deepening of the global energy crisis,the existing level of energy production in countries has been unable to meet the pace of domestic economic growth,the increasingly prominent internal contradictions make the optimization of capacity structure has become a critical issue.Among the many available energy sources,nuclear energy as a clean and efficient new energy gradually sought after by people.The integrated head of this paper is the key equipment in the nuclear power plant.The quality of the performance directly determines the energy efficiency of the whole nuclear power plant.No safe and efficient operation.Therefore,we need to carry out the formation of this kind of forging and the overall study.In this paper,based on the physical model of the material,the forming process of the integrated head is studied and discussed by the combination of experimental operation and numerical simulation:After a series of heating and thermal insulation experiments,the reasonable forging temperature range of SA508-3CL steel was determined from 1200℃ to 900℃,and the mathematical model of grain growth was established according to the experimental results.At the same time,According to the True stress-True strain curve obtained by thermal simulation compression test,the high temperature flow stress model and the static and dynamic recrystallization model under certain deformation conditions were established.According to the thermoplastic deformation properties of the material,designed two sets of forming the integrated head of the effective forging process-die forging and drawing,rational design based on the size of the two sets of tooling in the process,using the finite element simulation software was head forming plastic deformation process and forming after the end of the organization step by step research and comparison the results are as follows:in the aspect of forming effect,the forging of the two sets of processes can meet the requirements of the size of the nuclear head.However,in the actual production,drawing complex slab needed by rotary table,to get through the basin and process,is applicable to such forging rotary Taiwan has yet widely used in China’s major factories,so drawing difficult to be used in actual production.In the aspect of microstructure,the final average grain size of the 2 schemes is too thick,so the control of the internal structure can only be accomplished by the subsequent heat treatment process.To sum up,we are more inclined to adopt the die forging process for the production of this kind of forgings.