Research On Zirconium Alloys Pipe Straightening Mechanism And Its Equipment

Zirconium alloys pipe is used to be nuclear fuel cladding tube in nuclear reactor, and the thin-wall zirconium pipe manufacture precision is so high that manual straightening technology can not meet the requirements, and automatic precise straightening technology must be developed.Two basic problems about the straightening stroke calculation and the combination of press and support points in the pipe straightening technology were put forward according to the anti-bend leveling principle and analysis of pipe deformation characteristics. The pipe single step straightening calculation controlled by stroke had been built up from the elastic plastic theory. The pipe stress and strain in straightening deformation had been analyzed based on elastic-plastic theory, and the flatten rate computation formula was built from the plane displacement triangle series assumption. The simulation result expressed the flatten factor was hard effected by the load exerted on the pipe.The least square method was applied in level measuring system errors analysis. The reset spring rigidity optimization was performed by the bond graph. And the minimum measuring points around the pipe wall was decided in the quadratic discriminate analysis, and the level touch measuring system errors from the pipe radius was researched by the fitting function methods, and the level length optimization was performed.The hydraulic proportion serve system had been designed to meet the straightening press function. The system dynamic characteristics were calculated through the transfer function methods, and simulation experiments performed. Fuzzy logical PID control was presented to realize the press precise movement, and the positioning precision was less than0.02mm.The overall design scheme of the zirconium pipe straightening press was put forward based on the theory research and process design, some key main machine body such as main control system, hydraulic system, detecting system, straightening work bench, traverse table and the automatic feeding and unloading system were designed. And the experimental results expressed the Zirconium alloys pipe straightening whole set equipment well meet the actual requirements of the manufacture precision.