Research On Forming Technique In Half Wave Resonance Superconducting Cavity

Clean nuclear fission energy and nuclear waste transmutation processing are important directions of our country’s future energy strategy, the core technology of ADS (Accelerator Driven Subcritical Nuclear Power System) is a Superconducting Proton Linac, and superconducting cavity is the key component of the superconducting accelerator, utilising pure niobium sheet metal to form a half wave resonance of the superconducting cavity technology, there is no domestic reference. In view of the above question, forming technology is studied systematically the half wave resonance of superconducting cavityFirstly, CATIA is utilised to draw the main components of the HWR(half wave resonance) superconducting cavity, which are the middle of the outer cavities mold, the inner cavities mold and cover plate mold. In order to meet the need of the finite element simulation, room temperature tensile test of the pure niobium sheet has been proceed, to measure material properties of pure niobium; and the circle compression test has been proceeded, to measure friction coefficients of dry friction, graphite lubricants, oil and perfluoropolyether grease. In order to find the best lubricant, the finite element simulation of sheet metal forming for the four friction coefficients has been proceeded, and the influence for wall thickness of the molding has been observed.Finite element simulation software ABAQUS is utilised to finish the forming process simulations of the middle of the outer cavities mold, the inner cavities mold and cover plate. Optimum size of sheet metal forming based on the quasi-static criterion has been found. The cover plate inner diameter is formed by stretch flanging, which leads to the wall thickness reduction phenomenon. Via modifying cover plate mold, simulation has been proceeded again, until to meet the size need of cover plate high frequency surface. The forming test of the main components for the HWR superconducting cavity has been proceeded which are based on the result of simulation, to finish the formings of the middle of the outer cavities mold, the inner cavities mold and cover plate, and under the same parameters, to form pieces of pure niobium.U-shaped free bend springback model is simulated, and U-shaped bend springback of the pure niobium plates is tested. The finite element simulation adopts dynamic explicit to simulate the plates forming process and static implicit to simulate the plates springback process. The influence factors of springback are analyzed, the smaller falling velocity, the higher springback simulation accuracy; the bigger the die round corners, the greater the springback value; the smaller the gap of pouch and die, the less the springback value. Via springback test checking the reliability of simulation results, and the forming of the superconducting cavities main components is springback simulated, for U-shaped parts, the control methods of springback are analyzed.