Research On Punching Performance Of A Zirconium Alloy Strip

With the continuous development of China's economy and society,the whole country's demand for energy is also growing day by day.Only nuclear power is stable and environmentally friendly among the world's existing sources of electricity.In nuclear power equipment,nuclear fuel assemblies are assembled and welded by a variety of strips.As an important part of nuclear fuel assembly,strip is mostly made by cold stamping.and needs to use the zirconium alloy material with better nuclear performance.But zirconium alloy property is more special,it is difficult to manufacture in cold stamping.Therefore,the whole manufacturing process to process parameters and layout and process layout requirements are more stringent.In this paper,the punching performance of a zirconium alloy strip in nuclear fuel assembly is studied.The research contents are as follows:(1)The anisotropy of the material is explained by the polar diagram analysis;The anisotropic properties of the materials were verified by mechanical property tests and the mechanical property parameters were calculated.The forming limit test was carried out to obtain the FLC which characterized the forming limit performance of the material.(2)The two key forming features in the strip were simulated and analyzed within the adjustable range of production conditions,and the process parameters were optimized.Through the single factor analysis,it is found that the change of blanking clearance has a relatively great influence on the maximum thinning rate,and the coupling relationship among various factors is obtained by the multi-factor coupling simulation analysis.The optimized process parameter ratio can reduce the maximum thinning rate and improve the safety margin of blanking.(3)The layout scheme and the layout of blanking process were designed,and the optimization results of single feature simulation were applied to the progressive simulation true analysis to evaluate the simulation effect,the feasibility of the layout scheme and the blanking performance of the product.In addition,the blanking direction,the layout scheme and the blanking process steps are also determined.The progressive blanking simulation is carried out by Autoform,and the conclusion that the strip manufacturing can meet the requirements under the proposed blanking process scheme is obtained.(4)Design the mold,debug the related equipment,and carry out the actual physical punching test and verification according to the parameter ratio,layout scheme and working procedure mentioned above to get the product.Then,the key dimensions are detected,and the conclusion of strip flushability is drawn by analyzing the data.In this paper,the punching ability of a zirconium alloy strip was investigated under the condition of existing production equipment.Through research and test,it is found that: by improving the default parameters of the equipment to the optimized parameters,the maximum thinning rate of the characteristics is reduced,the blanking margin is improved,and the product is successfully blanked through design layout and process layout;The key dimensions were tested,indicating that the strips had met the production requirements.