Research Of Nuclear Power Material SS508-3Steel Inhomogeneous Hot Deformation Experiment And Numerical Simulation

Nuclear power pressure vessels is a key component of the nuclear powerequipment, which takes the function of fixing and inclusiving the reactor coreand reactor components to confine nuclear fuel fission reaction in a sealedspace, therefore, it is called the "heart" equipment of pressurized waterreactor nuclear power plant.Based on the previous research results, the paper take the commonlyused nuclear pressure vessel material SA508-3steel as study object, utilizeGleeble1500thermal simulation testing machine to complete the hotcompression simulation experiments below950℃. The high temperatureflow stress curve of the material below950℃is obtained. The flow stressmodel suitable for the material in the temperature range is obtained byregressing the experiment data according to the characteristics of the flowstress of the stage. The flow stress calculated by the model is consistent withthe experimental results, which means the model can be used in numericalsimulation of the material’s thermal deformation and provide determinantsfor the thermal processing.The grain growth laws of SA508-3steel under different temperaturesand holding time was studied by the insulation experiment, the initial forgingtemperature of the material is determined and the grain growth model of thematerial during insulation stage is established which provide basis for theinitial forging temperature determination in the forging process and the initialmicrostructure setting in the numerical simulation.The SA508-3steel inhomogeneous hot deformation experiments werecarried out by using320tons hydraulic machines and box-type resistancefurnace, and the load of the experiment were recorded. Recrystallization grain size and microhardness of given position were measured bymetallographic experiment and microhardness experiment. Make secondarydevelopment on the SA508-3steel dynamic recrystallization model obtainedby Fubo, and used in the numerical simulation of inhomogeneous hotdeformation experiment. Then comparing the results of microstructureobtained by physical experiments and numerical simulation respectively,the trend of grain size distribution is basically agreed, grain sizes areconsistent with the numerical simulation results, which reveal the influencelaw of strain, strain rate and temperature on dynamic recrystallization,meanwhile, which verify the validity of the secondary developed program ondynamic recrystallization.The secondary developed program were used in numerical simulation ofCAP1400evaporator head1:1.5forming process, microstructural evolutionand dynamic recrystallization fraction of evaporator head forming processwere obtained through the simulation. Analysis was executed combining withmulti-physics field. The results have certain guiding significance to thedevelopment of actual production process.