Study On Simulation Of Forging Process For Nuclear Power Tube Plate

Nuclear power tube plate is a typical large round forging, and its internal cracks arejointly determined by the level of the material quality and forging process. For thefailure phenomenon of the tube plate flaw, the route of this paper was from the steelmaterial named18MnD5of the tube sheet to some of forging process parameters, inorder to analyse the reasons for the forging cracks of tube plate.The subject used the3D solid modeling software CATIA to construct three-dimensional solid model of the tube plate of the Nuclear Power,and use Hypermesh tomesh, DEFORM which is a finite element analysis software is used to analyse andcompute numerically the forging process of the Nuclear power tube plate. On the basisof the rigid viscoplastic FEM theory,and using130t Nuclear power tube plate for theobject of study, this paper used the combining method of the theoretical analysis andnumerical simulation to analyse.Firstly,this paper did numerical simulation and finiteelement analysis for the flat upsetting and cone-plate upsetting in the blank with orwithout segregation. Secondly, this paper did numerical simulation and finite elementanalysis for the forming process of the tube plate,and found the reasons causing cracksin the tube plate.The main contents of the paper is as follows:①This paper used the optical microscope, SEM, EDS to analyze the failed tubeplate material sampling of the forging state,and use Gleeble—1500D to do thehigh-temperature tensile test,and the result of the test gained the high-temperatureplasticity chart of18MnD5,and found the homogeneous deformation degree of thematerial before fracture.②This paper used the testing machine of TMTS thermal simulation to do staticand recrystallization experiment, and gained more conducive to clear the residual effectin the high deformation temperature for18MnD5in stopping forging at the pressure,compared to the effect of the lower deformation temperature in stopping forging at thepressure,and further deformation could be implemented on a new basis withoutregarding to pre-overlay,whcih provided a viable channel for us to change the pressurestrategy to the implementation of large deformation upsetting without inducing cracks.③Using the high temperature welding experiment on forging hammer,we found that static recrystallization is a quick process,and found the best time to stop forgingpacking,which had an important significance in guiding the actual production.④This paper did numerical simulation and calculation for the flat upsetting andcone-plate upsetting process of the Nuclear power tube plate, and researched thepresence of segregation could cause forging to crack and tendency on the flip in itsinternal and external surface.So it should be considered non-homogeneousmaterials,which provided practical significance for researching the forging crackproblem of the round forgings.⑤By numerical simulation of tube sheet in molding process,we found that itshould start the rotating flattening after the second cone-plate upsetting and stoppingforging pressure about30seconds,in order to avoid the emergence of cracks.The simulation and calculation developed a new idea for the study of the forgingcracks of the round forgings,and laid the foundation for deeply study the cracking of theforgings.